1 // SPDX-License-Identifier: GPL-2.0
3 * ring buffer based function tracer
5 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
8 * Originally taken from the RT patch by:
9 * Arnaldo Carvalho de Melo <acme@redhat.com>
11 * Based on code from the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
15 #include <linux/ring_buffer.h>
16 #include <generated/utsrelease.h>
17 #include <linux/stacktrace.h>
18 #include <linux/writeback.h>
19 #include <linux/kallsyms.h>
20 #include <linux/security.h>
21 #include <linux/seq_file.h>
22 #include <linux/irqflags.h>
23 #include <linux/debugfs.h>
24 #include <linux/tracefs.h>
25 #include <linux/pagemap.h>
26 #include <linux/hardirq.h>
27 #include <linux/linkage.h>
28 #include <linux/uaccess.h>
29 #include <linux/vmalloc.h>
30 #include <linux/ftrace.h>
31 #include <linux/module.h>
32 #include <linux/percpu.h>
33 #include <linux/splice.h>
34 #include <linux/kdebug.h>
35 #include <linux/string.h>
36 #include <linux/mount.h>
37 #include <linux/rwsem.h>
38 #include <linux/slab.h>
39 #include <linux/ctype.h>
40 #include <linux/init.h>
41 #include <linux/panic_notifier.h>
42 #include <linux/poll.h>
43 #include <linux/nmi.h>
45 #include <linux/trace.h>
46 #include <linux/sched/clock.h>
47 #include <linux/sched/rt.h>
48 #include <linux/fsnotify.h>
49 #include <linux/irq_work.h>
50 #include <linux/workqueue.h>
52 #include <asm/setup.h> /* COMMAND_LINE_SIZE */
55 #include "trace_output.h"
58 * On boot up, the ring buffer is set to the minimum size, so that
59 * we do not waste memory on systems that are not using tracing.
61 bool ring_buffer_expanded;
63 #ifdef CONFIG_FTRACE_STARTUP_TEST
65 * We need to change this state when a selftest is running.
66 * A selftest will lurk into the ring-buffer to count the
67 * entries inserted during the selftest although some concurrent
68 * insertions into the ring-buffer such as trace_printk could occurred
69 * at the same time, giving false positive or negative results.
71 static bool __read_mostly tracing_selftest_running;
74 * If boot-time tracing including tracers/events via kernel cmdline
75 * is running, we do not want to run SELFTEST.
77 bool __read_mostly tracing_selftest_disabled;
79 void __init disable_tracing_selftest(const char *reason)
81 if (!tracing_selftest_disabled) {
82 tracing_selftest_disabled = true;
83 pr_info("Ftrace startup test is disabled due to %s\n", reason);
87 #define tracing_selftest_running 0
88 #define tracing_selftest_disabled 0
91 /* Pipe tracepoints to printk */
92 static struct trace_iterator *tracepoint_print_iter;
93 int tracepoint_printk;
94 static bool tracepoint_printk_stop_on_boot __initdata;
95 static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
97 /* For tracers that don't implement custom flags */
98 static struct tracer_opt dummy_tracer_opt[] = {
103 dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
109 * To prevent the comm cache from being overwritten when no
110 * tracing is active, only save the comm when a trace event
113 static DEFINE_PER_CPU(bool, trace_taskinfo_save);
116 * Kill all tracing for good (never come back).
117 * It is initialized to 1 but will turn to zero if the initialization
118 * of the tracer is successful. But that is the only place that sets
121 static int tracing_disabled = 1;
123 cpumask_var_t __read_mostly tracing_buffer_mask;
126 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
128 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
129 * is set, then ftrace_dump is called. This will output the contents
130 * of the ftrace buffers to the console. This is very useful for
131 * capturing traces that lead to crashes and outputing it to a
134 * It is default off, but you can enable it with either specifying
135 * "ftrace_dump_on_oops" in the kernel command line, or setting
136 * /proc/sys/kernel/ftrace_dump_on_oops
137 * Set 1 if you want to dump buffers of all CPUs
138 * Set 2 if you want to dump the buffer of the CPU that triggered oops
141 enum ftrace_dump_mode ftrace_dump_on_oops;
143 /* When set, tracing will stop when a WARN*() is hit */
144 int __disable_trace_on_warning;
146 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
147 /* Map of enums to their values, for "eval_map" file */
148 struct trace_eval_map_head {
150 unsigned long length;
153 union trace_eval_map_item;
155 struct trace_eval_map_tail {
157 * "end" is first and points to NULL as it must be different
158 * than "mod" or "eval_string"
160 union trace_eval_map_item *next;
161 const char *end; /* points to NULL */
164 static DEFINE_MUTEX(trace_eval_mutex);
167 * The trace_eval_maps are saved in an array with two extra elements,
168 * one at the beginning, and one at the end. The beginning item contains
169 * the count of the saved maps (head.length), and the module they
170 * belong to if not built in (head.mod). The ending item contains a
171 * pointer to the next array of saved eval_map items.
173 union trace_eval_map_item {
174 struct trace_eval_map map;
175 struct trace_eval_map_head head;
176 struct trace_eval_map_tail tail;
179 static union trace_eval_map_item *trace_eval_maps;
180 #endif /* CONFIG_TRACE_EVAL_MAP_FILE */
182 int tracing_set_tracer(struct trace_array *tr, const char *buf);
183 static void ftrace_trace_userstack(struct trace_array *tr,
184 struct trace_buffer *buffer,
185 unsigned int trace_ctx);
187 #define MAX_TRACER_SIZE 100
188 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
189 static char *default_bootup_tracer;
191 static bool allocate_snapshot;
192 static bool snapshot_at_boot;
194 static char boot_instance_info[COMMAND_LINE_SIZE] __initdata;
195 static int boot_instance_index;
197 static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata;
198 static int boot_snapshot_index;
200 static int __init set_cmdline_ftrace(char *str)
202 strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
203 default_bootup_tracer = bootup_tracer_buf;
204 /* We are using ftrace early, expand it */
205 ring_buffer_expanded = true;
208 __setup("ftrace=", set_cmdline_ftrace);
210 static int __init set_ftrace_dump_on_oops(char *str)
212 if (*str++ != '=' || !*str || !strcmp("1", str)) {
213 ftrace_dump_on_oops = DUMP_ALL;
217 if (!strcmp("orig_cpu", str) || !strcmp("2", str)) {
218 ftrace_dump_on_oops = DUMP_ORIG;
224 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
226 static int __init stop_trace_on_warning(char *str)
228 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
229 __disable_trace_on_warning = 1;
232 __setup("traceoff_on_warning", stop_trace_on_warning);
234 static int __init boot_alloc_snapshot(char *str)
236 char *slot = boot_snapshot_info + boot_snapshot_index;
237 int left = sizeof(boot_snapshot_info) - boot_snapshot_index;
242 if (strlen(str) >= left)
245 ret = snprintf(slot, left, "%s\t", str);
246 boot_snapshot_index += ret;
248 allocate_snapshot = true;
249 /* We also need the main ring buffer expanded */
250 ring_buffer_expanded = true;
254 __setup("alloc_snapshot", boot_alloc_snapshot);
257 static int __init boot_snapshot(char *str)
259 snapshot_at_boot = true;
260 boot_alloc_snapshot(str);
263 __setup("ftrace_boot_snapshot", boot_snapshot);
266 static int __init boot_instance(char *str)
268 char *slot = boot_instance_info + boot_instance_index;
269 int left = sizeof(boot_instance_info) - boot_instance_index;
272 if (strlen(str) >= left)
275 ret = snprintf(slot, left, "%s\t", str);
276 boot_instance_index += ret;
280 __setup("trace_instance=", boot_instance);
283 static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
285 static int __init set_trace_boot_options(char *str)
287 strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
290 __setup("trace_options=", set_trace_boot_options);
292 static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
293 static char *trace_boot_clock __initdata;
295 static int __init set_trace_boot_clock(char *str)
297 strscpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
298 trace_boot_clock = trace_boot_clock_buf;
301 __setup("trace_clock=", set_trace_boot_clock);
303 static int __init set_tracepoint_printk(char *str)
305 /* Ignore the "tp_printk_stop_on_boot" param */
309 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
310 tracepoint_printk = 1;
313 __setup("tp_printk", set_tracepoint_printk);
315 static int __init set_tracepoint_printk_stop(char *str)
317 tracepoint_printk_stop_on_boot = true;
320 __setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop);
322 unsigned long long ns2usecs(u64 nsec)
330 trace_process_export(struct trace_export *export,
331 struct ring_buffer_event *event, int flag)
333 struct trace_entry *entry;
334 unsigned int size = 0;
336 if (export->flags & flag) {
337 entry = ring_buffer_event_data(event);
338 size = ring_buffer_event_length(event);
339 export->write(export, entry, size);
343 static DEFINE_MUTEX(ftrace_export_lock);
345 static struct trace_export __rcu *ftrace_exports_list __read_mostly;
347 static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled);
348 static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled);
349 static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled);
351 static inline void ftrace_exports_enable(struct trace_export *export)
353 if (export->flags & TRACE_EXPORT_FUNCTION)
354 static_branch_inc(&trace_function_exports_enabled);
356 if (export->flags & TRACE_EXPORT_EVENT)
357 static_branch_inc(&trace_event_exports_enabled);
359 if (export->flags & TRACE_EXPORT_MARKER)
360 static_branch_inc(&trace_marker_exports_enabled);
363 static inline void ftrace_exports_disable(struct trace_export *export)
365 if (export->flags & TRACE_EXPORT_FUNCTION)
366 static_branch_dec(&trace_function_exports_enabled);
368 if (export->flags & TRACE_EXPORT_EVENT)
369 static_branch_dec(&trace_event_exports_enabled);
371 if (export->flags & TRACE_EXPORT_MARKER)
372 static_branch_dec(&trace_marker_exports_enabled);
375 static void ftrace_exports(struct ring_buffer_event *event, int flag)
377 struct trace_export *export;
379 preempt_disable_notrace();
381 export = rcu_dereference_raw_check(ftrace_exports_list);
383 trace_process_export(export, event, flag);
384 export = rcu_dereference_raw_check(export->next);
387 preempt_enable_notrace();
391 add_trace_export(struct trace_export **list, struct trace_export *export)
393 rcu_assign_pointer(export->next, *list);
395 * We are entering export into the list but another
396 * CPU might be walking that list. We need to make sure
397 * the export->next pointer is valid before another CPU sees
398 * the export pointer included into the list.
400 rcu_assign_pointer(*list, export);
404 rm_trace_export(struct trace_export **list, struct trace_export *export)
406 struct trace_export **p;
408 for (p = list; *p != NULL; p = &(*p)->next)
415 rcu_assign_pointer(*p, (*p)->next);
421 add_ftrace_export(struct trace_export **list, struct trace_export *export)
423 ftrace_exports_enable(export);
425 add_trace_export(list, export);
429 rm_ftrace_export(struct trace_export **list, struct trace_export *export)
433 ret = rm_trace_export(list, export);
434 ftrace_exports_disable(export);
439 int register_ftrace_export(struct trace_export *export)
441 if (WARN_ON_ONCE(!export->write))
444 mutex_lock(&ftrace_export_lock);
446 add_ftrace_export(&ftrace_exports_list, export);
448 mutex_unlock(&ftrace_export_lock);
452 EXPORT_SYMBOL_GPL(register_ftrace_export);
454 int unregister_ftrace_export(struct trace_export *export)
458 mutex_lock(&ftrace_export_lock);
460 ret = rm_ftrace_export(&ftrace_exports_list, export);
462 mutex_unlock(&ftrace_export_lock);
466 EXPORT_SYMBOL_GPL(unregister_ftrace_export);
468 /* trace_flags holds trace_options default values */
469 #define TRACE_DEFAULT_FLAGS \
470 (FUNCTION_DEFAULT_FLAGS | \
471 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
472 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
473 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
474 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | \
477 /* trace_options that are only supported by global_trace */
478 #define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
479 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
481 /* trace_flags that are default zero for instances */
482 #define ZEROED_TRACE_FLAGS \
483 (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
486 * The global_trace is the descriptor that holds the top-level tracing
487 * buffers for the live tracing.
489 static struct trace_array global_trace = {
490 .trace_flags = TRACE_DEFAULT_FLAGS,
493 LIST_HEAD(ftrace_trace_arrays);
495 int trace_array_get(struct trace_array *this_tr)
497 struct trace_array *tr;
500 mutex_lock(&trace_types_lock);
501 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
508 mutex_unlock(&trace_types_lock);
513 static void __trace_array_put(struct trace_array *this_tr)
515 WARN_ON(!this_tr->ref);
520 * trace_array_put - Decrement the reference counter for this trace array.
521 * @this_tr : pointer to the trace array
523 * NOTE: Use this when we no longer need the trace array returned by
524 * trace_array_get_by_name(). This ensures the trace array can be later
528 void trace_array_put(struct trace_array *this_tr)
533 mutex_lock(&trace_types_lock);
534 __trace_array_put(this_tr);
535 mutex_unlock(&trace_types_lock);
537 EXPORT_SYMBOL_GPL(trace_array_put);
539 int tracing_check_open_get_tr(struct trace_array *tr)
543 ret = security_locked_down(LOCKDOWN_TRACEFS);
547 if (tracing_disabled)
550 if (tr && trace_array_get(tr) < 0)
556 int call_filter_check_discard(struct trace_event_call *call, void *rec,
557 struct trace_buffer *buffer,
558 struct ring_buffer_event *event)
560 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
561 !filter_match_preds(call->filter, rec)) {
562 __trace_event_discard_commit(buffer, event);
570 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
571 * @filtered_pids: The list of pids to check
572 * @search_pid: The PID to find in @filtered_pids
574 * Returns true if @search_pid is found in @filtered_pids, and false otherwise.
577 trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
579 return trace_pid_list_is_set(filtered_pids, search_pid);
583 * trace_ignore_this_task - should a task be ignored for tracing
584 * @filtered_pids: The list of pids to check
585 * @filtered_no_pids: The list of pids not to be traced
586 * @task: The task that should be ignored if not filtered
588 * Checks if @task should be traced or not from @filtered_pids.
589 * Returns true if @task should *NOT* be traced.
590 * Returns false if @task should be traced.
593 trace_ignore_this_task(struct trace_pid_list *filtered_pids,
594 struct trace_pid_list *filtered_no_pids,
595 struct task_struct *task)
598 * If filtered_no_pids is not empty, and the task's pid is listed
599 * in filtered_no_pids, then return true.
600 * Otherwise, if filtered_pids is empty, that means we can
601 * trace all tasks. If it has content, then only trace pids
602 * within filtered_pids.
605 return (filtered_pids &&
606 !trace_find_filtered_pid(filtered_pids, task->pid)) ||
608 trace_find_filtered_pid(filtered_no_pids, task->pid));
612 * trace_filter_add_remove_task - Add or remove a task from a pid_list
613 * @pid_list: The list to modify
614 * @self: The current task for fork or NULL for exit
615 * @task: The task to add or remove
617 * If adding a task, if @self is defined, the task is only added if @self
618 * is also included in @pid_list. This happens on fork and tasks should
619 * only be added when the parent is listed. If @self is NULL, then the
620 * @task pid will be removed from the list, which would happen on exit
623 void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
624 struct task_struct *self,
625 struct task_struct *task)
630 /* For forks, we only add if the forking task is listed */
632 if (!trace_find_filtered_pid(pid_list, self->pid))
636 /* "self" is set for forks, and NULL for exits */
638 trace_pid_list_set(pid_list, task->pid);
640 trace_pid_list_clear(pid_list, task->pid);
644 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
645 * @pid_list: The pid list to show
646 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
647 * @pos: The position of the file
649 * This is used by the seq_file "next" operation to iterate the pids
650 * listed in a trace_pid_list structure.
652 * Returns the pid+1 as we want to display pid of zero, but NULL would
653 * stop the iteration.
655 void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
657 long pid = (unsigned long)v;
662 /* pid already is +1 of the actual previous bit */
663 if (trace_pid_list_next(pid_list, pid, &next) < 0)
668 /* Return pid + 1 to allow zero to be represented */
669 return (void *)(pid + 1);
673 * trace_pid_start - Used for seq_file to start reading pid lists
674 * @pid_list: The pid list to show
675 * @pos: The position of the file
677 * This is used by seq_file "start" operation to start the iteration
680 * Returns the pid+1 as we want to display pid of zero, but NULL would
681 * stop the iteration.
683 void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
689 if (trace_pid_list_first(pid_list, &first) < 0)
694 /* Return pid + 1 so that zero can be the exit value */
695 for (pid++; pid && l < *pos;
696 pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
702 * trace_pid_show - show the current pid in seq_file processing
703 * @m: The seq_file structure to write into
704 * @v: A void pointer of the pid (+1) value to display
706 * Can be directly used by seq_file operations to display the current
709 int trace_pid_show(struct seq_file *m, void *v)
711 unsigned long pid = (unsigned long)v - 1;
713 seq_printf(m, "%lu\n", pid);
717 /* 128 should be much more than enough */
718 #define PID_BUF_SIZE 127
720 int trace_pid_write(struct trace_pid_list *filtered_pids,
721 struct trace_pid_list **new_pid_list,
722 const char __user *ubuf, size_t cnt)
724 struct trace_pid_list *pid_list;
725 struct trace_parser parser;
733 if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
737 * Always recreate a new array. The write is an all or nothing
738 * operation. Always create a new array when adding new pids by
739 * the user. If the operation fails, then the current list is
742 pid_list = trace_pid_list_alloc();
744 trace_parser_put(&parser);
749 /* copy the current bits to the new max */
750 ret = trace_pid_list_first(filtered_pids, &pid);
752 trace_pid_list_set(pid_list, pid);
753 ret = trace_pid_list_next(filtered_pids, pid + 1, &pid);
763 ret = trace_get_user(&parser, ubuf, cnt, &pos);
771 if (!trace_parser_loaded(&parser))
775 if (kstrtoul(parser.buffer, 0, &val))
780 if (trace_pid_list_set(pid_list, pid) < 0) {
786 trace_parser_clear(&parser);
789 trace_parser_put(&parser);
792 trace_pid_list_free(pid_list);
797 /* Cleared the list of pids */
798 trace_pid_list_free(pid_list);
802 *new_pid_list = pid_list;
807 static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu)
811 /* Early boot up does not have a buffer yet */
813 return trace_clock_local();
815 ts = ring_buffer_time_stamp(buf->buffer);
816 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
821 u64 ftrace_now(int cpu)
823 return buffer_ftrace_now(&global_trace.array_buffer, cpu);
827 * tracing_is_enabled - Show if global_trace has been enabled
829 * Shows if the global trace has been enabled or not. It uses the
830 * mirror flag "buffer_disabled" to be used in fast paths such as for
831 * the irqsoff tracer. But it may be inaccurate due to races. If you
832 * need to know the accurate state, use tracing_is_on() which is a little
833 * slower, but accurate.
835 int tracing_is_enabled(void)
838 * For quick access (irqsoff uses this in fast path), just
839 * return the mirror variable of the state of the ring buffer.
840 * It's a little racy, but we don't really care.
843 return !global_trace.buffer_disabled;
847 * trace_buf_size is the size in bytes that is allocated
848 * for a buffer. Note, the number of bytes is always rounded
851 * This number is purposely set to a low number of 16384.
852 * If the dump on oops happens, it will be much appreciated
853 * to not have to wait for all that output. Anyway this can be
854 * boot time and run time configurable.
856 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
858 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
860 /* trace_types holds a link list of available tracers. */
861 static struct tracer *trace_types __read_mostly;
864 * trace_types_lock is used to protect the trace_types list.
866 DEFINE_MUTEX(trace_types_lock);
869 * serialize the access of the ring buffer
871 * ring buffer serializes readers, but it is low level protection.
872 * The validity of the events (which returns by ring_buffer_peek() ..etc)
873 * are not protected by ring buffer.
875 * The content of events may become garbage if we allow other process consumes
876 * these events concurrently:
877 * A) the page of the consumed events may become a normal page
878 * (not reader page) in ring buffer, and this page will be rewritten
879 * by events producer.
880 * B) The page of the consumed events may become a page for splice_read,
881 * and this page will be returned to system.
883 * These primitives allow multi process access to different cpu ring buffer
886 * These primitives don't distinguish read-only and read-consume access.
887 * Multi read-only access are also serialized.
891 static DECLARE_RWSEM(all_cpu_access_lock);
892 static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
894 static inline void trace_access_lock(int cpu)
896 if (cpu == RING_BUFFER_ALL_CPUS) {
897 /* gain it for accessing the whole ring buffer. */
898 down_write(&all_cpu_access_lock);
900 /* gain it for accessing a cpu ring buffer. */
902 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
903 down_read(&all_cpu_access_lock);
905 /* Secondly block other access to this @cpu ring buffer. */
906 mutex_lock(&per_cpu(cpu_access_lock, cpu));
910 static inline void trace_access_unlock(int cpu)
912 if (cpu == RING_BUFFER_ALL_CPUS) {
913 up_write(&all_cpu_access_lock);
915 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
916 up_read(&all_cpu_access_lock);
920 static inline void trace_access_lock_init(void)
924 for_each_possible_cpu(cpu)
925 mutex_init(&per_cpu(cpu_access_lock, cpu));
930 static DEFINE_MUTEX(access_lock);
932 static inline void trace_access_lock(int cpu)
935 mutex_lock(&access_lock);
938 static inline void trace_access_unlock(int cpu)
941 mutex_unlock(&access_lock);
944 static inline void trace_access_lock_init(void)
950 #ifdef CONFIG_STACKTRACE
951 static void __ftrace_trace_stack(struct trace_buffer *buffer,
952 unsigned int trace_ctx,
953 int skip, struct pt_regs *regs);
954 static inline void ftrace_trace_stack(struct trace_array *tr,
955 struct trace_buffer *buffer,
956 unsigned int trace_ctx,
957 int skip, struct pt_regs *regs);
960 static inline void __ftrace_trace_stack(struct trace_buffer *buffer,
961 unsigned int trace_ctx,
962 int skip, struct pt_regs *regs)
965 static inline void ftrace_trace_stack(struct trace_array *tr,
966 struct trace_buffer *buffer,
967 unsigned long trace_ctx,
968 int skip, struct pt_regs *regs)
974 static __always_inline void
975 trace_event_setup(struct ring_buffer_event *event,
976 int type, unsigned int trace_ctx)
978 struct trace_entry *ent = ring_buffer_event_data(event);
980 tracing_generic_entry_update(ent, type, trace_ctx);
983 static __always_inline struct ring_buffer_event *
984 __trace_buffer_lock_reserve(struct trace_buffer *buffer,
987 unsigned int trace_ctx)
989 struct ring_buffer_event *event;
991 event = ring_buffer_lock_reserve(buffer, len);
993 trace_event_setup(event, type, trace_ctx);
998 void tracer_tracing_on(struct trace_array *tr)
1000 if (tr->array_buffer.buffer)
1001 ring_buffer_record_on(tr->array_buffer.buffer);
1003 * This flag is looked at when buffers haven't been allocated
1004 * yet, or by some tracers (like irqsoff), that just want to
1005 * know if the ring buffer has been disabled, but it can handle
1006 * races of where it gets disabled but we still do a record.
1007 * As the check is in the fast path of the tracers, it is more
1008 * important to be fast than accurate.
1010 tr->buffer_disabled = 0;
1011 /* Make the flag seen by readers */
1016 * tracing_on - enable tracing buffers
1018 * This function enables tracing buffers that may have been
1019 * disabled with tracing_off.
1021 void tracing_on(void)
1023 tracer_tracing_on(&global_trace);
1025 EXPORT_SYMBOL_GPL(tracing_on);
1028 static __always_inline void
1029 __buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event)
1031 __this_cpu_write(trace_taskinfo_save, true);
1033 /* If this is the temp buffer, we need to commit fully */
1034 if (this_cpu_read(trace_buffered_event) == event) {
1035 /* Length is in event->array[0] */
1036 ring_buffer_write(buffer, event->array[0], &event->array[1]);
1037 /* Release the temp buffer */
1038 this_cpu_dec(trace_buffered_event_cnt);
1039 /* ring_buffer_unlock_commit() enables preemption */
1040 preempt_enable_notrace();
1042 ring_buffer_unlock_commit(buffer);
1045 int __trace_array_puts(struct trace_array *tr, unsigned long ip,
1046 const char *str, int size)
1048 struct ring_buffer_event *event;
1049 struct trace_buffer *buffer;
1050 struct print_entry *entry;
1051 unsigned int trace_ctx;
1054 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
1057 if (unlikely(tracing_selftest_running && tr == &global_trace))
1060 if (unlikely(tracing_disabled))
1063 alloc = sizeof(*entry) + size + 2; /* possible \n added */
1065 trace_ctx = tracing_gen_ctx();
1066 buffer = tr->array_buffer.buffer;
1067 ring_buffer_nest_start(buffer);
1068 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
1075 entry = ring_buffer_event_data(event);
1078 memcpy(&entry->buf, str, size);
1080 /* Add a newline if necessary */
1081 if (entry->buf[size - 1] != '\n') {
1082 entry->buf[size] = '\n';
1083 entry->buf[size + 1] = '\0';
1085 entry->buf[size] = '\0';
1087 __buffer_unlock_commit(buffer, event);
1088 ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
1090 ring_buffer_nest_end(buffer);
1093 EXPORT_SYMBOL_GPL(__trace_array_puts);
1096 * __trace_puts - write a constant string into the trace buffer.
1097 * @ip: The address of the caller
1098 * @str: The constant string to write
1099 * @size: The size of the string.
1101 int __trace_puts(unsigned long ip, const char *str, int size)
1103 return __trace_array_puts(&global_trace, ip, str, size);
1105 EXPORT_SYMBOL_GPL(__trace_puts);
1108 * __trace_bputs - write the pointer to a constant string into trace buffer
1109 * @ip: The address of the caller
1110 * @str: The constant string to write to the buffer to
1112 int __trace_bputs(unsigned long ip, const char *str)
1114 struct ring_buffer_event *event;
1115 struct trace_buffer *buffer;
1116 struct bputs_entry *entry;
1117 unsigned int trace_ctx;
1118 int size = sizeof(struct bputs_entry);
1121 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
1124 if (unlikely(tracing_selftest_running || tracing_disabled))
1127 trace_ctx = tracing_gen_ctx();
1128 buffer = global_trace.array_buffer.buffer;
1130 ring_buffer_nest_start(buffer);
1131 event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
1136 entry = ring_buffer_event_data(event);
1140 __buffer_unlock_commit(buffer, event);
1141 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
1145 ring_buffer_nest_end(buffer);
1148 EXPORT_SYMBOL_GPL(__trace_bputs);
1150 #ifdef CONFIG_TRACER_SNAPSHOT
1151 static void tracing_snapshot_instance_cond(struct trace_array *tr,
1154 struct tracer *tracer = tr->current_trace;
1155 unsigned long flags;
1158 trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
1159 trace_array_puts(tr, "*** snapshot is being ignored ***\n");
1163 if (!tr->allocated_snapshot) {
1164 trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n");
1165 trace_array_puts(tr, "*** stopping trace here! ***\n");
1166 tracer_tracing_off(tr);
1170 /* Note, snapshot can not be used when the tracer uses it */
1171 if (tracer->use_max_tr) {
1172 trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n");
1173 trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
1177 local_irq_save(flags);
1178 update_max_tr(tr, current, smp_processor_id(), cond_data);
1179 local_irq_restore(flags);
1182 void tracing_snapshot_instance(struct trace_array *tr)
1184 tracing_snapshot_instance_cond(tr, NULL);
1188 * tracing_snapshot - take a snapshot of the current buffer.
1190 * This causes a swap between the snapshot buffer and the current live
1191 * tracing buffer. You can use this to take snapshots of the live
1192 * trace when some condition is triggered, but continue to trace.
1194 * Note, make sure to allocate the snapshot with either
1195 * a tracing_snapshot_alloc(), or by doing it manually
1196 * with: echo 1 > /sys/kernel/tracing/snapshot
1198 * If the snapshot buffer is not allocated, it will stop tracing.
1199 * Basically making a permanent snapshot.
1201 void tracing_snapshot(void)
1203 struct trace_array *tr = &global_trace;
1205 tracing_snapshot_instance(tr);
1207 EXPORT_SYMBOL_GPL(tracing_snapshot);
1210 * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
1211 * @tr: The tracing instance to snapshot
1212 * @cond_data: The data to be tested conditionally, and possibly saved
1214 * This is the same as tracing_snapshot() except that the snapshot is
1215 * conditional - the snapshot will only happen if the
1216 * cond_snapshot.update() implementation receiving the cond_data
1217 * returns true, which means that the trace array's cond_snapshot
1218 * update() operation used the cond_data to determine whether the
1219 * snapshot should be taken, and if it was, presumably saved it along
1220 * with the snapshot.
1222 void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1224 tracing_snapshot_instance_cond(tr, cond_data);
1226 EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1229 * tracing_cond_snapshot_data - get the user data associated with a snapshot
1230 * @tr: The tracing instance
1232 * When the user enables a conditional snapshot using
1233 * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
1234 * with the snapshot. This accessor is used to retrieve it.
1236 * Should not be called from cond_snapshot.update(), since it takes
1237 * the tr->max_lock lock, which the code calling
1238 * cond_snapshot.update() has already done.
1240 * Returns the cond_data associated with the trace array's snapshot.
1242 void *tracing_cond_snapshot_data(struct trace_array *tr)
1244 void *cond_data = NULL;
1246 local_irq_disable();
1247 arch_spin_lock(&tr->max_lock);
1249 if (tr->cond_snapshot)
1250 cond_data = tr->cond_snapshot->cond_data;
1252 arch_spin_unlock(&tr->max_lock);
1257 EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1259 static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
1260 struct array_buffer *size_buf, int cpu_id);
1261 static void set_buffer_entries(struct array_buffer *buf, unsigned long val);
1263 int tracing_alloc_snapshot_instance(struct trace_array *tr)
1267 if (!tr->allocated_snapshot) {
1269 /* allocate spare buffer */
1270 ret = resize_buffer_duplicate_size(&tr->max_buffer,
1271 &tr->array_buffer, RING_BUFFER_ALL_CPUS);
1275 tr->allocated_snapshot = true;
1281 static void free_snapshot(struct trace_array *tr)
1284 * We don't free the ring buffer. instead, resize it because
1285 * The max_tr ring buffer has some state (e.g. ring->clock) and
1286 * we want preserve it.
1288 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
1289 set_buffer_entries(&tr->max_buffer, 1);
1290 tracing_reset_online_cpus(&tr->max_buffer);
1291 tr->allocated_snapshot = false;
1295 * tracing_alloc_snapshot - allocate snapshot buffer.
1297 * This only allocates the snapshot buffer if it isn't already
1298 * allocated - it doesn't also take a snapshot.
1300 * This is meant to be used in cases where the snapshot buffer needs
1301 * to be set up for events that can't sleep but need to be able to
1302 * trigger a snapshot.
1304 int tracing_alloc_snapshot(void)
1306 struct trace_array *tr = &global_trace;
1309 ret = tracing_alloc_snapshot_instance(tr);
1314 EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1317 * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
1319 * This is similar to tracing_snapshot(), but it will allocate the
1320 * snapshot buffer if it isn't already allocated. Use this only
1321 * where it is safe to sleep, as the allocation may sleep.
1323 * This causes a swap between the snapshot buffer and the current live
1324 * tracing buffer. You can use this to take snapshots of the live
1325 * trace when some condition is triggered, but continue to trace.
1327 void tracing_snapshot_alloc(void)
1331 ret = tracing_alloc_snapshot();
1337 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1340 * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
1341 * @tr: The tracing instance
1342 * @cond_data: User data to associate with the snapshot
1343 * @update: Implementation of the cond_snapshot update function
1345 * Check whether the conditional snapshot for the given instance has
1346 * already been enabled, or if the current tracer is already using a
1347 * snapshot; if so, return -EBUSY, else create a cond_snapshot and
1348 * save the cond_data and update function inside.
1350 * Returns 0 if successful, error otherwise.
1352 int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
1353 cond_update_fn_t update)
1355 struct cond_snapshot *cond_snapshot;
1358 cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
1362 cond_snapshot->cond_data = cond_data;
1363 cond_snapshot->update = update;
1365 mutex_lock(&trace_types_lock);
1367 ret = tracing_alloc_snapshot_instance(tr);
1371 if (tr->current_trace->use_max_tr) {
1377 * The cond_snapshot can only change to NULL without the
1378 * trace_types_lock. We don't care if we race with it going
1379 * to NULL, but we want to make sure that it's not set to
1380 * something other than NULL when we get here, which we can
1381 * do safely with only holding the trace_types_lock and not
1382 * having to take the max_lock.
1384 if (tr->cond_snapshot) {
1389 local_irq_disable();
1390 arch_spin_lock(&tr->max_lock);
1391 tr->cond_snapshot = cond_snapshot;
1392 arch_spin_unlock(&tr->max_lock);
1395 mutex_unlock(&trace_types_lock);
1400 mutex_unlock(&trace_types_lock);
1401 kfree(cond_snapshot);
1404 EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1407 * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
1408 * @tr: The tracing instance
1410 * Check whether the conditional snapshot for the given instance is
1411 * enabled; if so, free the cond_snapshot associated with it,
1412 * otherwise return -EINVAL.
1414 * Returns 0 if successful, error otherwise.
1416 int tracing_snapshot_cond_disable(struct trace_array *tr)
1420 local_irq_disable();
1421 arch_spin_lock(&tr->max_lock);
1423 if (!tr->cond_snapshot)
1426 kfree(tr->cond_snapshot);
1427 tr->cond_snapshot = NULL;
1430 arch_spin_unlock(&tr->max_lock);
1435 EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1437 void tracing_snapshot(void)
1439 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1441 EXPORT_SYMBOL_GPL(tracing_snapshot);
1442 void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1444 WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
1446 EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1447 int tracing_alloc_snapshot(void)
1449 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1452 EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1453 void tracing_snapshot_alloc(void)
1458 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1459 void *tracing_cond_snapshot_data(struct trace_array *tr)
1463 EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1464 int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
1468 EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1469 int tracing_snapshot_cond_disable(struct trace_array *tr)
1473 EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1474 #define free_snapshot(tr) do { } while (0)
1475 #endif /* CONFIG_TRACER_SNAPSHOT */
1477 void tracer_tracing_off(struct trace_array *tr)
1479 if (tr->array_buffer.buffer)
1480 ring_buffer_record_off(tr->array_buffer.buffer);
1482 * This flag is looked at when buffers haven't been allocated
1483 * yet, or by some tracers (like irqsoff), that just want to
1484 * know if the ring buffer has been disabled, but it can handle
1485 * races of where it gets disabled but we still do a record.
1486 * As the check is in the fast path of the tracers, it is more
1487 * important to be fast than accurate.
1489 tr->buffer_disabled = 1;
1490 /* Make the flag seen by readers */
1495 * tracing_off - turn off tracing buffers
1497 * This function stops the tracing buffers from recording data.
1498 * It does not disable any overhead the tracers themselves may
1499 * be causing. This function simply causes all recording to
1500 * the ring buffers to fail.
1502 void tracing_off(void)
1504 tracer_tracing_off(&global_trace);
1506 EXPORT_SYMBOL_GPL(tracing_off);
1508 void disable_trace_on_warning(void)
1510 if (__disable_trace_on_warning) {
1511 trace_array_printk_buf(global_trace.array_buffer.buffer, _THIS_IP_,
1512 "Disabling tracing due to warning\n");
1518 * tracer_tracing_is_on - show real state of ring buffer enabled
1519 * @tr : the trace array to know if ring buffer is enabled
1521 * Shows real state of the ring buffer if it is enabled or not.
1523 bool tracer_tracing_is_on(struct trace_array *tr)
1525 if (tr->array_buffer.buffer)
1526 return ring_buffer_record_is_on(tr->array_buffer.buffer);
1527 return !tr->buffer_disabled;
1531 * tracing_is_on - show state of ring buffers enabled
1533 int tracing_is_on(void)
1535 return tracer_tracing_is_on(&global_trace);
1537 EXPORT_SYMBOL_GPL(tracing_is_on);
1539 static int __init set_buf_size(char *str)
1541 unsigned long buf_size;
1545 buf_size = memparse(str, &str);
1547 * nr_entries can not be zero and the startup
1548 * tests require some buffer space. Therefore
1549 * ensure we have at least 4096 bytes of buffer.
1551 trace_buf_size = max(4096UL, buf_size);
1554 __setup("trace_buf_size=", set_buf_size);
1556 static int __init set_tracing_thresh(char *str)
1558 unsigned long threshold;
1563 ret = kstrtoul(str, 0, &threshold);
1566 tracing_thresh = threshold * 1000;
1569 __setup("tracing_thresh=", set_tracing_thresh);
1571 unsigned long nsecs_to_usecs(unsigned long nsecs)
1573 return nsecs / 1000;
1577 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1578 * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
1579 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1580 * of strings in the order that the evals (enum) were defined.
1585 /* These must match the bit positions in trace_iterator_flags */
1586 static const char *trace_options[] = {
1594 int in_ns; /* is this clock in nanoseconds? */
1595 } trace_clocks[] = {
1596 { trace_clock_local, "local", 1 },
1597 { trace_clock_global, "global", 1 },
1598 { trace_clock_counter, "counter", 0 },
1599 { trace_clock_jiffies, "uptime", 0 },
1600 { trace_clock, "perf", 1 },
1601 { ktime_get_mono_fast_ns, "mono", 1 },
1602 { ktime_get_raw_fast_ns, "mono_raw", 1 },
1603 { ktime_get_boot_fast_ns, "boot", 1 },
1604 { ktime_get_tai_fast_ns, "tai", 1 },
1608 bool trace_clock_in_ns(struct trace_array *tr)
1610 if (trace_clocks[tr->clock_id].in_ns)
1617 * trace_parser_get_init - gets the buffer for trace parser
1619 int trace_parser_get_init(struct trace_parser *parser, int size)
1621 memset(parser, 0, sizeof(*parser));
1623 parser->buffer = kmalloc(size, GFP_KERNEL);
1624 if (!parser->buffer)
1627 parser->size = size;
1632 * trace_parser_put - frees the buffer for trace parser
1634 void trace_parser_put(struct trace_parser *parser)
1636 kfree(parser->buffer);
1637 parser->buffer = NULL;
1641 * trace_get_user - reads the user input string separated by space
1642 * (matched by isspace(ch))
1644 * For each string found the 'struct trace_parser' is updated,
1645 * and the function returns.
1647 * Returns number of bytes read.
1649 * See kernel/trace/trace.h for 'struct trace_parser' details.
1651 int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1652 size_t cnt, loff_t *ppos)
1659 trace_parser_clear(parser);
1661 ret = get_user(ch, ubuf++);
1669 * The parser is not finished with the last write,
1670 * continue reading the user input without skipping spaces.
1672 if (!parser->cont) {
1673 /* skip white space */
1674 while (cnt && isspace(ch)) {
1675 ret = get_user(ch, ubuf++);
1684 /* only spaces were written */
1685 if (isspace(ch) || !ch) {
1692 /* read the non-space input */
1693 while (cnt && !isspace(ch) && ch) {
1694 if (parser->idx < parser->size - 1)
1695 parser->buffer[parser->idx++] = ch;
1700 ret = get_user(ch, ubuf++);
1707 /* We either got finished input or we have to wait for another call. */
1708 if (isspace(ch) || !ch) {
1709 parser->buffer[parser->idx] = 0;
1710 parser->cont = false;
1711 } else if (parser->idx < parser->size - 1) {
1712 parser->cont = true;
1713 parser->buffer[parser->idx++] = ch;
1714 /* Make sure the parsed string always terminates with '\0'. */
1715 parser->buffer[parser->idx] = 0;
1728 /* TODO add a seq_buf_to_buffer() */
1729 static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1733 if (trace_seq_used(s) <= s->seq.readpos)
1736 len = trace_seq_used(s) - s->seq.readpos;
1739 memcpy(buf, s->buffer + s->seq.readpos, cnt);
1741 s->seq.readpos += cnt;
1745 unsigned long __read_mostly tracing_thresh;
1747 #ifdef CONFIG_TRACER_MAX_TRACE
1748 static const struct file_operations tracing_max_lat_fops;
1750 #ifdef LATENCY_FS_NOTIFY
1752 static struct workqueue_struct *fsnotify_wq;
1754 static void latency_fsnotify_workfn(struct work_struct *work)
1756 struct trace_array *tr = container_of(work, struct trace_array,
1758 fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY);
1761 static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
1763 struct trace_array *tr = container_of(iwork, struct trace_array,
1765 queue_work(fsnotify_wq, &tr->fsnotify_work);
1768 static void trace_create_maxlat_file(struct trace_array *tr,
1769 struct dentry *d_tracer)
1771 INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
1772 init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
1773 tr->d_max_latency = trace_create_file("tracing_max_latency",
1776 &tracing_max_lat_fops);
1779 __init static int latency_fsnotify_init(void)
1781 fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
1782 WQ_UNBOUND | WQ_HIGHPRI, 0);
1784 pr_err("Unable to allocate tr_max_lat_wq\n");
1790 late_initcall_sync(latency_fsnotify_init);
1792 void latency_fsnotify(struct trace_array *tr)
1797 * We cannot call queue_work(&tr->fsnotify_work) from here because it's
1798 * possible that we are called from __schedule() or do_idle(), which
1799 * could cause a deadlock.
1801 irq_work_queue(&tr->fsnotify_irqwork);
1804 #else /* !LATENCY_FS_NOTIFY */
1806 #define trace_create_maxlat_file(tr, d_tracer) \
1807 trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \
1808 d_tracer, tr, &tracing_max_lat_fops)
1813 * Copy the new maximum trace into the separate maximum-trace
1814 * structure. (this way the maximum trace is permanently saved,
1815 * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
1818 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1820 struct array_buffer *trace_buf = &tr->array_buffer;
1821 struct array_buffer *max_buf = &tr->max_buffer;
1822 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1823 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1826 max_buf->time_start = data->preempt_timestamp;
1828 max_data->saved_latency = tr->max_latency;
1829 max_data->critical_start = data->critical_start;
1830 max_data->critical_end = data->critical_end;
1832 strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1833 max_data->pid = tsk->pid;
1835 * If tsk == current, then use current_uid(), as that does not use
1836 * RCU. The irq tracer can be called out of RCU scope.
1839 max_data->uid = current_uid();
1841 max_data->uid = task_uid(tsk);
1843 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1844 max_data->policy = tsk->policy;
1845 max_data->rt_priority = tsk->rt_priority;
1847 /* record this tasks comm */
1848 tracing_record_cmdline(tsk);
1849 latency_fsnotify(tr);
1853 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1855 * @tsk: the task with the latency
1856 * @cpu: The cpu that initiated the trace.
1857 * @cond_data: User data associated with a conditional snapshot
1859 * Flip the buffers between the @tr and the max_tr and record information
1860 * about which task was the cause of this latency.
1863 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
1869 WARN_ON_ONCE(!irqs_disabled());
1871 if (!tr->allocated_snapshot) {
1872 /* Only the nop tracer should hit this when disabling */
1873 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1877 arch_spin_lock(&tr->max_lock);
1879 /* Inherit the recordable setting from array_buffer */
1880 if (ring_buffer_record_is_set_on(tr->array_buffer.buffer))
1881 ring_buffer_record_on(tr->max_buffer.buffer);
1883 ring_buffer_record_off(tr->max_buffer.buffer);
1885 #ifdef CONFIG_TRACER_SNAPSHOT
1886 if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data)) {
1887 arch_spin_unlock(&tr->max_lock);
1891 swap(tr->array_buffer.buffer, tr->max_buffer.buffer);
1893 __update_max_tr(tr, tsk, cpu);
1895 arch_spin_unlock(&tr->max_lock);
1899 * update_max_tr_single - only copy one trace over, and reset the rest
1901 * @tsk: task with the latency
1902 * @cpu: the cpu of the buffer to copy.
1904 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1907 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1914 WARN_ON_ONCE(!irqs_disabled());
1915 if (!tr->allocated_snapshot) {
1916 /* Only the nop tracer should hit this when disabling */
1917 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1921 arch_spin_lock(&tr->max_lock);
1923 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu);
1925 if (ret == -EBUSY) {
1927 * We failed to swap the buffer due to a commit taking
1928 * place on this CPU. We fail to record, but we reset
1929 * the max trace buffer (no one writes directly to it)
1930 * and flag that it failed.
1931 * Another reason is resize is in progress.
1933 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1934 "Failed to swap buffers due to commit or resize in progress\n");
1937 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1939 __update_max_tr(tr, tsk, cpu);
1940 arch_spin_unlock(&tr->max_lock);
1943 #endif /* CONFIG_TRACER_MAX_TRACE */
1945 static int wait_on_pipe(struct trace_iterator *iter, int full)
1947 /* Iterators are static, they should be filled or empty */
1948 if (trace_buffer_iter(iter, iter->cpu_file))
1951 return ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file,
1955 #ifdef CONFIG_FTRACE_STARTUP_TEST
1956 static bool selftests_can_run;
1958 struct trace_selftests {
1959 struct list_head list;
1960 struct tracer *type;
1963 static LIST_HEAD(postponed_selftests);
1965 static int save_selftest(struct tracer *type)
1967 struct trace_selftests *selftest;
1969 selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
1973 selftest->type = type;
1974 list_add(&selftest->list, &postponed_selftests);
1978 static int run_tracer_selftest(struct tracer *type)
1980 struct trace_array *tr = &global_trace;
1981 struct tracer *saved_tracer = tr->current_trace;
1984 if (!type->selftest || tracing_selftest_disabled)
1988 * If a tracer registers early in boot up (before scheduling is
1989 * initialized and such), then do not run its selftests yet.
1990 * Instead, run it a little later in the boot process.
1992 if (!selftests_can_run)
1993 return save_selftest(type);
1995 if (!tracing_is_on()) {
1996 pr_warn("Selftest for tracer %s skipped due to tracing disabled\n",
2002 * Run a selftest on this tracer.
2003 * Here we reset the trace buffer, and set the current
2004 * tracer to be this tracer. The tracer can then run some
2005 * internal tracing to verify that everything is in order.
2006 * If we fail, we do not register this tracer.
2008 tracing_reset_online_cpus(&tr->array_buffer);
2010 tr->current_trace = type;
2012 #ifdef CONFIG_TRACER_MAX_TRACE
2013 if (type->use_max_tr) {
2014 /* If we expanded the buffers, make sure the max is expanded too */
2015 if (ring_buffer_expanded)
2016 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
2017 RING_BUFFER_ALL_CPUS);
2018 tr->allocated_snapshot = true;
2022 /* the test is responsible for initializing and enabling */
2023 pr_info("Testing tracer %s: ", type->name);
2024 ret = type->selftest(type, tr);
2025 /* the test is responsible for resetting too */
2026 tr->current_trace = saved_tracer;
2028 printk(KERN_CONT "FAILED!\n");
2029 /* Add the warning after printing 'FAILED' */
2033 /* Only reset on passing, to avoid touching corrupted buffers */
2034 tracing_reset_online_cpus(&tr->array_buffer);
2036 #ifdef CONFIG_TRACER_MAX_TRACE
2037 if (type->use_max_tr) {
2038 tr->allocated_snapshot = false;
2040 /* Shrink the max buffer again */
2041 if (ring_buffer_expanded)
2042 ring_buffer_resize(tr->max_buffer.buffer, 1,
2043 RING_BUFFER_ALL_CPUS);
2047 printk(KERN_CONT "PASSED\n");
2051 static int do_run_tracer_selftest(struct tracer *type)
2056 * Tests can take a long time, especially if they are run one after the
2057 * other, as does happen during bootup when all the tracers are
2058 * registered. This could cause the soft lockup watchdog to trigger.
2062 tracing_selftest_running = true;
2063 ret = run_tracer_selftest(type);
2064 tracing_selftest_running = false;
2069 static __init int init_trace_selftests(void)
2071 struct trace_selftests *p, *n;
2072 struct tracer *t, **last;
2075 selftests_can_run = true;
2077 mutex_lock(&trace_types_lock);
2079 if (list_empty(&postponed_selftests))
2082 pr_info("Running postponed tracer tests:\n");
2084 tracing_selftest_running = true;
2085 list_for_each_entry_safe(p, n, &postponed_selftests, list) {
2086 /* This loop can take minutes when sanitizers are enabled, so
2087 * lets make sure we allow RCU processing.
2090 ret = run_tracer_selftest(p->type);
2091 /* If the test fails, then warn and remove from available_tracers */
2093 WARN(1, "tracer: %s failed selftest, disabling\n",
2095 last = &trace_types;
2096 for (t = trace_types; t; t = t->next) {
2107 tracing_selftest_running = false;
2110 mutex_unlock(&trace_types_lock);
2114 core_initcall(init_trace_selftests);
2116 static inline int run_tracer_selftest(struct tracer *type)
2120 static inline int do_run_tracer_selftest(struct tracer *type)
2124 #endif /* CONFIG_FTRACE_STARTUP_TEST */
2126 static void add_tracer_options(struct trace_array *tr, struct tracer *t);
2128 static void __init apply_trace_boot_options(void);
2131 * register_tracer - register a tracer with the ftrace system.
2132 * @type: the plugin for the tracer
2134 * Register a new plugin tracer.
2136 int __init register_tracer(struct tracer *type)
2142 pr_info("Tracer must have a name\n");
2146 if (strlen(type->name) >= MAX_TRACER_SIZE) {
2147 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
2151 if (security_locked_down(LOCKDOWN_TRACEFS)) {
2152 pr_warn("Can not register tracer %s due to lockdown\n",
2157 mutex_lock(&trace_types_lock);
2159 for (t = trace_types; t; t = t->next) {
2160 if (strcmp(type->name, t->name) == 0) {
2162 pr_info("Tracer %s already registered\n",
2169 if (!type->set_flag)
2170 type->set_flag = &dummy_set_flag;
2172 /*allocate a dummy tracer_flags*/
2173 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
2178 type->flags->val = 0;
2179 type->flags->opts = dummy_tracer_opt;
2181 if (!type->flags->opts)
2182 type->flags->opts = dummy_tracer_opt;
2184 /* store the tracer for __set_tracer_option */
2185 type->flags->trace = type;
2187 ret = do_run_tracer_selftest(type);
2191 type->next = trace_types;
2193 add_tracer_options(&global_trace, type);
2196 mutex_unlock(&trace_types_lock);
2198 if (ret || !default_bootup_tracer)
2201 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
2204 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
2205 /* Do we want this tracer to start on bootup? */
2206 tracing_set_tracer(&global_trace, type->name);
2207 default_bootup_tracer = NULL;
2209 apply_trace_boot_options();
2211 /* disable other selftests, since this will break it. */
2212 disable_tracing_selftest("running a tracer");
2218 static void tracing_reset_cpu(struct array_buffer *buf, int cpu)
2220 struct trace_buffer *buffer = buf->buffer;
2225 ring_buffer_record_disable(buffer);
2227 /* Make sure all commits have finished */
2229 ring_buffer_reset_cpu(buffer, cpu);
2231 ring_buffer_record_enable(buffer);
2234 void tracing_reset_online_cpus(struct array_buffer *buf)
2236 struct trace_buffer *buffer = buf->buffer;
2241 ring_buffer_record_disable(buffer);
2243 /* Make sure all commits have finished */
2246 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
2248 ring_buffer_reset_online_cpus(buffer);
2250 ring_buffer_record_enable(buffer);
2253 /* Must have trace_types_lock held */
2254 void tracing_reset_all_online_cpus_unlocked(void)
2256 struct trace_array *tr;
2258 lockdep_assert_held(&trace_types_lock);
2260 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2261 if (!tr->clear_trace)
2263 tr->clear_trace = false;
2264 tracing_reset_online_cpus(&tr->array_buffer);
2265 #ifdef CONFIG_TRACER_MAX_TRACE
2266 tracing_reset_online_cpus(&tr->max_buffer);
2271 void tracing_reset_all_online_cpus(void)
2273 mutex_lock(&trace_types_lock);
2274 tracing_reset_all_online_cpus_unlocked();
2275 mutex_unlock(&trace_types_lock);
2279 * The tgid_map array maps from pid to tgid; i.e. the value stored at index i
2280 * is the tgid last observed corresponding to pid=i.
2282 static int *tgid_map;
2284 /* The maximum valid index into tgid_map. */
2285 static size_t tgid_map_max;
2287 #define SAVED_CMDLINES_DEFAULT 128
2288 #define NO_CMDLINE_MAP UINT_MAX
2290 * Preemption must be disabled before acquiring trace_cmdline_lock.
2291 * The various trace_arrays' max_lock must be acquired in a context
2292 * where interrupt is disabled.
2294 static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
2295 struct saved_cmdlines_buffer {
2296 unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
2297 unsigned *map_cmdline_to_pid;
2298 unsigned cmdline_num;
2300 char *saved_cmdlines;
2302 static struct saved_cmdlines_buffer *savedcmd;
2304 static inline char *get_saved_cmdlines(int idx)
2306 return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
2309 static inline void set_cmdline(int idx, const char *cmdline)
2311 strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
2314 static int allocate_cmdlines_buffer(unsigned int val,
2315 struct saved_cmdlines_buffer *s)
2317 s->map_cmdline_to_pid = kmalloc_array(val,
2318 sizeof(*s->map_cmdline_to_pid),
2320 if (!s->map_cmdline_to_pid)
2323 s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);
2324 if (!s->saved_cmdlines) {
2325 kfree(s->map_cmdline_to_pid);
2330 s->cmdline_num = val;
2331 memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
2332 sizeof(s->map_pid_to_cmdline));
2333 memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
2334 val * sizeof(*s->map_cmdline_to_pid));
2339 static int trace_create_savedcmd(void)
2343 savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
2347 ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
2357 int is_tracing_stopped(void)
2359 return global_trace.stop_count;
2363 * tracing_start - quick start of the tracer
2365 * If tracing is enabled but was stopped by tracing_stop,
2366 * this will start the tracer back up.
2368 void tracing_start(void)
2370 struct trace_buffer *buffer;
2371 unsigned long flags;
2373 if (tracing_disabled)
2376 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
2377 if (--global_trace.stop_count) {
2378 if (global_trace.stop_count < 0) {
2379 /* Someone screwed up their debugging */
2381 global_trace.stop_count = 0;
2386 /* Prevent the buffers from switching */
2387 arch_spin_lock(&global_trace.max_lock);
2389 buffer = global_trace.array_buffer.buffer;
2391 ring_buffer_record_enable(buffer);
2393 #ifdef CONFIG_TRACER_MAX_TRACE
2394 buffer = global_trace.max_buffer.buffer;
2396 ring_buffer_record_enable(buffer);
2399 arch_spin_unlock(&global_trace.max_lock);
2402 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
2405 static void tracing_start_tr(struct trace_array *tr)
2407 struct trace_buffer *buffer;
2408 unsigned long flags;
2410 if (tracing_disabled)
2413 /* If global, we need to also start the max tracer */
2414 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
2415 return tracing_start();
2417 raw_spin_lock_irqsave(&tr->start_lock, flags);
2419 if (--tr->stop_count) {
2420 if (tr->stop_count < 0) {
2421 /* Someone screwed up their debugging */
2428 buffer = tr->array_buffer.buffer;
2430 ring_buffer_record_enable(buffer);
2433 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2437 * tracing_stop - quick stop of the tracer
2439 * Light weight way to stop tracing. Use in conjunction with
2442 void tracing_stop(void)
2444 struct trace_buffer *buffer;
2445 unsigned long flags;
2447 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
2448 if (global_trace.stop_count++)
2451 /* Prevent the buffers from switching */
2452 arch_spin_lock(&global_trace.max_lock);
2454 buffer = global_trace.array_buffer.buffer;
2456 ring_buffer_record_disable(buffer);
2458 #ifdef CONFIG_TRACER_MAX_TRACE
2459 buffer = global_trace.max_buffer.buffer;
2461 ring_buffer_record_disable(buffer);
2464 arch_spin_unlock(&global_trace.max_lock);
2467 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
2470 static void tracing_stop_tr(struct trace_array *tr)
2472 struct trace_buffer *buffer;
2473 unsigned long flags;
2475 /* If global, we need to also stop the max tracer */
2476 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
2477 return tracing_stop();
2479 raw_spin_lock_irqsave(&tr->start_lock, flags);
2480 if (tr->stop_count++)
2483 buffer = tr->array_buffer.buffer;
2485 ring_buffer_record_disable(buffer);
2488 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2491 static int trace_save_cmdline(struct task_struct *tsk)
2495 /* treat recording of idle task as a success */
2499 tpid = tsk->pid & (PID_MAX_DEFAULT - 1);
2502 * It's not the end of the world if we don't get
2503 * the lock, but we also don't want to spin
2504 * nor do we want to disable interrupts,
2505 * so if we miss here, then better luck next time.
2507 * This is called within the scheduler and wake up, so interrupts
2508 * had better been disabled and run queue lock been held.
2510 lockdep_assert_preemption_disabled();
2511 if (!arch_spin_trylock(&trace_cmdline_lock))
2514 idx = savedcmd->map_pid_to_cmdline[tpid];
2515 if (idx == NO_CMDLINE_MAP) {
2516 idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
2518 savedcmd->map_pid_to_cmdline[tpid] = idx;
2519 savedcmd->cmdline_idx = idx;
2522 savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
2523 set_cmdline(idx, tsk->comm);
2525 arch_spin_unlock(&trace_cmdline_lock);
2530 static void __trace_find_cmdline(int pid, char comm[])
2536 strcpy(comm, "<idle>");
2540 if (WARN_ON_ONCE(pid < 0)) {
2541 strcpy(comm, "<XXX>");
2545 tpid = pid & (PID_MAX_DEFAULT - 1);
2546 map = savedcmd->map_pid_to_cmdline[tpid];
2547 if (map != NO_CMDLINE_MAP) {
2548 tpid = savedcmd->map_cmdline_to_pid[map];
2550 strscpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
2554 strcpy(comm, "<...>");
2557 void trace_find_cmdline(int pid, char comm[])
2560 arch_spin_lock(&trace_cmdline_lock);
2562 __trace_find_cmdline(pid, comm);
2564 arch_spin_unlock(&trace_cmdline_lock);
2568 static int *trace_find_tgid_ptr(int pid)
2571 * Pairs with the smp_store_release in set_tracer_flag() to ensure that
2572 * if we observe a non-NULL tgid_map then we also observe the correct
2575 int *map = smp_load_acquire(&tgid_map);
2577 if (unlikely(!map || pid > tgid_map_max))
2583 int trace_find_tgid(int pid)
2585 int *ptr = trace_find_tgid_ptr(pid);
2587 return ptr ? *ptr : 0;
2590 static int trace_save_tgid(struct task_struct *tsk)
2594 /* treat recording of idle task as a success */
2598 ptr = trace_find_tgid_ptr(tsk->pid);
2606 static bool tracing_record_taskinfo_skip(int flags)
2608 if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
2610 if (!__this_cpu_read(trace_taskinfo_save))
2616 * tracing_record_taskinfo - record the task info of a task
2618 * @task: task to record
2619 * @flags: TRACE_RECORD_CMDLINE for recording comm
2620 * TRACE_RECORD_TGID for recording tgid
2622 void tracing_record_taskinfo(struct task_struct *task, int flags)
2626 if (tracing_record_taskinfo_skip(flags))
2630 * Record as much task information as possible. If some fail, continue
2631 * to try to record the others.
2633 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task);
2634 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task);
2636 /* If recording any information failed, retry again soon. */
2640 __this_cpu_write(trace_taskinfo_save, false);
2644 * tracing_record_taskinfo_sched_switch - record task info for sched_switch
2646 * @prev: previous task during sched_switch
2647 * @next: next task during sched_switch
2648 * @flags: TRACE_RECORD_CMDLINE for recording comm
2649 * TRACE_RECORD_TGID for recording tgid
2651 void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
2652 struct task_struct *next, int flags)
2656 if (tracing_record_taskinfo_skip(flags))
2660 * Record as much task information as possible. If some fail, continue
2661 * to try to record the others.
2663 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev);
2664 done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next);
2665 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev);
2666 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next);
2668 /* If recording any information failed, retry again soon. */
2672 __this_cpu_write(trace_taskinfo_save, false);
2675 /* Helpers to record a specific task information */
2676 void tracing_record_cmdline(struct task_struct *task)
2678 tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
2681 void tracing_record_tgid(struct task_struct *task)
2683 tracing_record_taskinfo(task, TRACE_RECORD_TGID);
2687 * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
2688 * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
2689 * simplifies those functions and keeps them in sync.
2691 enum print_line_t trace_handle_return(struct trace_seq *s)
2693 return trace_seq_has_overflowed(s) ?
2694 TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
2696 EXPORT_SYMBOL_GPL(trace_handle_return);
2698 static unsigned short migration_disable_value(void)
2700 #if defined(CONFIG_SMP)
2701 return current->migration_disabled;
2707 unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
2709 unsigned int trace_flags = irqs_status;
2712 pc = preempt_count();
2715 trace_flags |= TRACE_FLAG_NMI;
2716 if (pc & HARDIRQ_MASK)
2717 trace_flags |= TRACE_FLAG_HARDIRQ;
2718 if (in_serving_softirq())
2719 trace_flags |= TRACE_FLAG_SOFTIRQ;
2720 if (softirq_count() >> (SOFTIRQ_SHIFT + 1))
2721 trace_flags |= TRACE_FLAG_BH_OFF;
2723 if (tif_need_resched())
2724 trace_flags |= TRACE_FLAG_NEED_RESCHED;
2725 if (test_preempt_need_resched())
2726 trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
2727 return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) |
2728 (min_t(unsigned int, migration_disable_value(), 0xf)) << 4;
2731 struct ring_buffer_event *
2732 trace_buffer_lock_reserve(struct trace_buffer *buffer,
2735 unsigned int trace_ctx)
2737 return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx);
2740 DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
2741 DEFINE_PER_CPU(int, trace_buffered_event_cnt);
2742 static int trace_buffered_event_ref;
2745 * trace_buffered_event_enable - enable buffering events
2747 * When events are being filtered, it is quicker to use a temporary
2748 * buffer to write the event data into if there's a likely chance
2749 * that it will not be committed. The discard of the ring buffer
2750 * is not as fast as committing, and is much slower than copying
2753 * When an event is to be filtered, allocate per cpu buffers to
2754 * write the event data into, and if the event is filtered and discarded
2755 * it is simply dropped, otherwise, the entire data is to be committed
2758 void trace_buffered_event_enable(void)
2760 struct ring_buffer_event *event;
2764 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2766 if (trace_buffered_event_ref++)
2769 for_each_tracing_cpu(cpu) {
2770 page = alloc_pages_node(cpu_to_node(cpu),
2771 GFP_KERNEL | __GFP_NORETRY, 0);
2775 event = page_address(page);
2776 memset(event, 0, sizeof(*event));
2778 per_cpu(trace_buffered_event, cpu) = event;
2781 if (cpu == smp_processor_id() &&
2782 __this_cpu_read(trace_buffered_event) !=
2783 per_cpu(trace_buffered_event, cpu))
2790 trace_buffered_event_disable();
2793 static void enable_trace_buffered_event(void *data)
2795 /* Probably not needed, but do it anyway */
2797 this_cpu_dec(trace_buffered_event_cnt);
2800 static void disable_trace_buffered_event(void *data)
2802 this_cpu_inc(trace_buffered_event_cnt);
2806 * trace_buffered_event_disable - disable buffering events
2808 * When a filter is removed, it is faster to not use the buffered
2809 * events, and to commit directly into the ring buffer. Free up
2810 * the temp buffers when there are no more users. This requires
2811 * special synchronization with current events.
2813 void trace_buffered_event_disable(void)
2817 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2819 if (WARN_ON_ONCE(!trace_buffered_event_ref))
2822 if (--trace_buffered_event_ref)
2826 /* For each CPU, set the buffer as used. */
2827 smp_call_function_many(tracing_buffer_mask,
2828 disable_trace_buffered_event, NULL, 1);
2831 /* Wait for all current users to finish */
2834 for_each_tracing_cpu(cpu) {
2835 free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2836 per_cpu(trace_buffered_event, cpu) = NULL;
2839 * Make sure trace_buffered_event is NULL before clearing
2840 * trace_buffered_event_cnt.
2845 /* Do the work on each cpu */
2846 smp_call_function_many(tracing_buffer_mask,
2847 enable_trace_buffered_event, NULL, 1);
2851 static struct trace_buffer *temp_buffer;
2853 struct ring_buffer_event *
2854 trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
2855 struct trace_event_file *trace_file,
2856 int type, unsigned long len,
2857 unsigned int trace_ctx)
2859 struct ring_buffer_event *entry;
2860 struct trace_array *tr = trace_file->tr;
2863 *current_rb = tr->array_buffer.buffer;
2865 if (!tr->no_filter_buffering_ref &&
2866 (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED))) {
2867 preempt_disable_notrace();
2869 * Filtering is on, so try to use the per cpu buffer first.
2870 * This buffer will simulate a ring_buffer_event,
2871 * where the type_len is zero and the array[0] will
2872 * hold the full length.
2873 * (see include/linux/ring-buffer.h for details on
2874 * how the ring_buffer_event is structured).
2876 * Using a temp buffer during filtering and copying it
2877 * on a matched filter is quicker than writing directly
2878 * into the ring buffer and then discarding it when
2879 * it doesn't match. That is because the discard
2880 * requires several atomic operations to get right.
2881 * Copying on match and doing nothing on a failed match
2882 * is still quicker than no copy on match, but having
2883 * to discard out of the ring buffer on a failed match.
2885 if ((entry = __this_cpu_read(trace_buffered_event))) {
2886 int max_len = PAGE_SIZE - struct_size(entry, array, 1);
2888 val = this_cpu_inc_return(trace_buffered_event_cnt);
2891 * Preemption is disabled, but interrupts and NMIs
2892 * can still come in now. If that happens after
2893 * the above increment, then it will have to go
2894 * back to the old method of allocating the event
2895 * on the ring buffer, and if the filter fails, it
2896 * will have to call ring_buffer_discard_commit()
2899 * Need to also check the unlikely case that the
2900 * length is bigger than the temp buffer size.
2901 * If that happens, then the reserve is pretty much
2902 * guaranteed to fail, as the ring buffer currently
2903 * only allows events less than a page. But that may
2904 * change in the future, so let the ring buffer reserve
2905 * handle the failure in that case.
2907 if (val == 1 && likely(len <= max_len)) {
2908 trace_event_setup(entry, type, trace_ctx);
2909 entry->array[0] = len;
2910 /* Return with preemption disabled */
2913 this_cpu_dec(trace_buffered_event_cnt);
2915 /* __trace_buffer_lock_reserve() disables preemption */
2916 preempt_enable_notrace();
2919 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2922 * If tracing is off, but we have triggers enabled
2923 * we still need to look at the event data. Use the temp_buffer
2924 * to store the trace event for the trigger to use. It's recursive
2925 * safe and will not be recorded anywhere.
2927 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2928 *current_rb = temp_buffer;
2929 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2934 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2936 static DEFINE_RAW_SPINLOCK(tracepoint_iter_lock);
2937 static DEFINE_MUTEX(tracepoint_printk_mutex);
2939 static void output_printk(struct trace_event_buffer *fbuffer)
2941 struct trace_event_call *event_call;
2942 struct trace_event_file *file;
2943 struct trace_event *event;
2944 unsigned long flags;
2945 struct trace_iterator *iter = tracepoint_print_iter;
2947 /* We should never get here if iter is NULL */
2948 if (WARN_ON_ONCE(!iter))
2951 event_call = fbuffer->trace_file->event_call;
2952 if (!event_call || !event_call->event.funcs ||
2953 !event_call->event.funcs->trace)
2956 file = fbuffer->trace_file;
2957 if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
2958 (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
2959 !filter_match_preds(file->filter, fbuffer->entry)))
2962 event = &fbuffer->trace_file->event_call->event;
2964 raw_spin_lock_irqsave(&tracepoint_iter_lock, flags);
2965 trace_seq_init(&iter->seq);
2966 iter->ent = fbuffer->entry;
2967 event_call->event.funcs->trace(iter, 0, event);
2968 trace_seq_putc(&iter->seq, 0);
2969 printk("%s", iter->seq.buffer);
2971 raw_spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2974 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
2975 void *buffer, size_t *lenp,
2978 int save_tracepoint_printk;
2981 mutex_lock(&tracepoint_printk_mutex);
2982 save_tracepoint_printk = tracepoint_printk;
2984 ret = proc_dointvec(table, write, buffer, lenp, ppos);
2987 * This will force exiting early, as tracepoint_printk
2988 * is always zero when tracepoint_printk_iter is not allocated
2990 if (!tracepoint_print_iter)
2991 tracepoint_printk = 0;
2993 if (save_tracepoint_printk == tracepoint_printk)
2996 if (tracepoint_printk)
2997 static_key_enable(&tracepoint_printk_key.key);
2999 static_key_disable(&tracepoint_printk_key.key);
3002 mutex_unlock(&tracepoint_printk_mutex);
3007 void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
3009 enum event_trigger_type tt = ETT_NONE;
3010 struct trace_event_file *file = fbuffer->trace_file;
3012 if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event,
3013 fbuffer->entry, &tt))
3016 if (static_key_false(&tracepoint_printk_key.key))
3017 output_printk(fbuffer);
3019 if (static_branch_unlikely(&trace_event_exports_enabled))
3020 ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT);
3022 trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer,
3023 fbuffer->event, fbuffer->trace_ctx, fbuffer->regs);
3027 event_triggers_post_call(file, tt);
3030 EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
3035 * trace_buffer_unlock_commit_regs()
3036 * trace_event_buffer_commit()
3037 * trace_event_raw_event_xxx()
3039 # define STACK_SKIP 3
3041 void trace_buffer_unlock_commit_regs(struct trace_array *tr,
3042 struct trace_buffer *buffer,
3043 struct ring_buffer_event *event,
3044 unsigned int trace_ctx,
3045 struct pt_regs *regs)
3047 __buffer_unlock_commit(buffer, event);
3050 * If regs is not set, then skip the necessary functions.
3051 * Note, we can still get here via blktrace, wakeup tracer
3052 * and mmiotrace, but that's ok if they lose a function or
3053 * two. They are not that meaningful.
3055 ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs);
3056 ftrace_trace_userstack(tr, buffer, trace_ctx);
3060 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
3063 trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
3064 struct ring_buffer_event *event)
3066 __buffer_unlock_commit(buffer, event);
3070 trace_function(struct trace_array *tr, unsigned long ip, unsigned long
3071 parent_ip, unsigned int trace_ctx)
3073 struct trace_event_call *call = &event_function;
3074 struct trace_buffer *buffer = tr->array_buffer.buffer;
3075 struct ring_buffer_event *event;
3076 struct ftrace_entry *entry;
3078 event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
3082 entry = ring_buffer_event_data(event);
3084 entry->parent_ip = parent_ip;
3086 if (!call_filter_check_discard(call, entry, buffer, event)) {
3087 if (static_branch_unlikely(&trace_function_exports_enabled))
3088 ftrace_exports(event, TRACE_EXPORT_FUNCTION);
3089 __buffer_unlock_commit(buffer, event);
3093 #ifdef CONFIG_STACKTRACE
3095 /* Allow 4 levels of nesting: normal, softirq, irq, NMI */
3096 #define FTRACE_KSTACK_NESTING 4
3098 #define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING)
3100 struct ftrace_stack {
3101 unsigned long calls[FTRACE_KSTACK_ENTRIES];
3105 struct ftrace_stacks {
3106 struct ftrace_stack stacks[FTRACE_KSTACK_NESTING];
3109 static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
3110 static DEFINE_PER_CPU(int, ftrace_stack_reserve);
3112 static void __ftrace_trace_stack(struct trace_buffer *buffer,
3113 unsigned int trace_ctx,
3114 int skip, struct pt_regs *regs)
3116 struct trace_event_call *call = &event_kernel_stack;
3117 struct ring_buffer_event *event;
3118 unsigned int size, nr_entries;
3119 struct ftrace_stack *fstack;
3120 struct stack_entry *entry;
3124 * Add one, for this function and the call to save_stack_trace()
3125 * If regs is set, then these functions will not be in the way.
3127 #ifndef CONFIG_UNWINDER_ORC
3132 preempt_disable_notrace();
3134 stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
3136 /* This should never happen. If it does, yell once and skip */
3137 if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING))
3141 * The above __this_cpu_inc_return() is 'atomic' cpu local. An
3142 * interrupt will either see the value pre increment or post
3143 * increment. If the interrupt happens pre increment it will have
3144 * restored the counter when it returns. We just need a barrier to
3145 * keep gcc from moving things around.
3149 fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
3150 size = ARRAY_SIZE(fstack->calls);
3153 nr_entries = stack_trace_save_regs(regs, fstack->calls,
3156 nr_entries = stack_trace_save(fstack->calls, size, skip);
3159 event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
3160 struct_size(entry, caller, nr_entries),
3164 entry = ring_buffer_event_data(event);
3166 entry->size = nr_entries;
3167 memcpy(&entry->caller, fstack->calls,
3168 flex_array_size(entry, caller, nr_entries));
3170 if (!call_filter_check_discard(call, entry, buffer, event))
3171 __buffer_unlock_commit(buffer, event);
3174 /* Again, don't let gcc optimize things here */
3176 __this_cpu_dec(ftrace_stack_reserve);
3177 preempt_enable_notrace();
3181 static inline void ftrace_trace_stack(struct trace_array *tr,
3182 struct trace_buffer *buffer,
3183 unsigned int trace_ctx,
3184 int skip, struct pt_regs *regs)
3186 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
3189 __ftrace_trace_stack(buffer, trace_ctx, skip, regs);
3192 void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
3195 struct trace_buffer *buffer = tr->array_buffer.buffer;
3197 if (rcu_is_watching()) {
3198 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3202 if (WARN_ON_ONCE(IS_ENABLED(CONFIG_GENERIC_ENTRY)))
3206 * When an NMI triggers, RCU is enabled via ct_nmi_enter(),
3207 * but if the above rcu_is_watching() failed, then the NMI
3208 * triggered someplace critical, and ct_irq_enter() should
3209 * not be called from NMI.
3211 if (unlikely(in_nmi()))
3214 ct_irq_enter_irqson();
3215 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3216 ct_irq_exit_irqson();
3220 * trace_dump_stack - record a stack back trace in the trace buffer
3221 * @skip: Number of functions to skip (helper handlers)
3223 void trace_dump_stack(int skip)
3225 if (tracing_disabled || tracing_selftest_running)
3228 #ifndef CONFIG_UNWINDER_ORC
3229 /* Skip 1 to skip this function. */
3232 __ftrace_trace_stack(global_trace.array_buffer.buffer,
3233 tracing_gen_ctx(), skip, NULL);
3235 EXPORT_SYMBOL_GPL(trace_dump_stack);
3237 #ifdef CONFIG_USER_STACKTRACE_SUPPORT
3238 static DEFINE_PER_CPU(int, user_stack_count);
3241 ftrace_trace_userstack(struct trace_array *tr,
3242 struct trace_buffer *buffer, unsigned int trace_ctx)
3244 struct trace_event_call *call = &event_user_stack;
3245 struct ring_buffer_event *event;
3246 struct userstack_entry *entry;
3248 if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
3252 * NMIs can not handle page faults, even with fix ups.
3253 * The save user stack can (and often does) fault.
3255 if (unlikely(in_nmi()))
3259 * prevent recursion, since the user stack tracing may
3260 * trigger other kernel events.
3263 if (__this_cpu_read(user_stack_count))
3266 __this_cpu_inc(user_stack_count);
3268 event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
3269 sizeof(*entry), trace_ctx);
3271 goto out_drop_count;
3272 entry = ring_buffer_event_data(event);
3274 entry->tgid = current->tgid;
3275 memset(&entry->caller, 0, sizeof(entry->caller));
3277 stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
3278 if (!call_filter_check_discard(call, entry, buffer, event))
3279 __buffer_unlock_commit(buffer, event);
3282 __this_cpu_dec(user_stack_count);
3286 #else /* CONFIG_USER_STACKTRACE_SUPPORT */
3287 static void ftrace_trace_userstack(struct trace_array *tr,
3288 struct trace_buffer *buffer,
3289 unsigned int trace_ctx)
3292 #endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
3294 #endif /* CONFIG_STACKTRACE */
3297 func_repeats_set_delta_ts(struct func_repeats_entry *entry,
3298 unsigned long long delta)
3300 entry->bottom_delta_ts = delta & U32_MAX;
3301 entry->top_delta_ts = (delta >> 32);
3304 void trace_last_func_repeats(struct trace_array *tr,
3305 struct trace_func_repeats *last_info,
3306 unsigned int trace_ctx)
3308 struct trace_buffer *buffer = tr->array_buffer.buffer;
3309 struct func_repeats_entry *entry;
3310 struct ring_buffer_event *event;
3313 event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS,
3314 sizeof(*entry), trace_ctx);
3318 delta = ring_buffer_event_time_stamp(buffer, event) -
3319 last_info->ts_last_call;
3321 entry = ring_buffer_event_data(event);
3322 entry->ip = last_info->ip;
3323 entry->parent_ip = last_info->parent_ip;
3324 entry->count = last_info->count;
3325 func_repeats_set_delta_ts(entry, delta);
3327 __buffer_unlock_commit(buffer, event);
3330 /* created for use with alloc_percpu */
3331 struct trace_buffer_struct {
3333 char buffer[4][TRACE_BUF_SIZE];
3336 static struct trace_buffer_struct __percpu *trace_percpu_buffer;
3339 * This allows for lockless recording. If we're nested too deeply, then
3340 * this returns NULL.
3342 static char *get_trace_buf(void)
3344 struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
3346 if (!trace_percpu_buffer || buffer->nesting >= 4)
3351 /* Interrupts must see nesting incremented before we use the buffer */
3353 return &buffer->buffer[buffer->nesting - 1][0];
3356 static void put_trace_buf(void)
3358 /* Don't let the decrement of nesting leak before this */
3360 this_cpu_dec(trace_percpu_buffer->nesting);
3363 static int alloc_percpu_trace_buffer(void)
3365 struct trace_buffer_struct __percpu *buffers;
3367 if (trace_percpu_buffer)
3370 buffers = alloc_percpu(struct trace_buffer_struct);
3371 if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer"))
3374 trace_percpu_buffer = buffers;
3378 static int buffers_allocated;
3380 void trace_printk_init_buffers(void)
3382 if (buffers_allocated)
3385 if (alloc_percpu_trace_buffer())
3388 /* trace_printk() is for debug use only. Don't use it in production. */
3391 pr_warn("**********************************************************\n");
3392 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3394 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
3396 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
3397 pr_warn("** unsafe for production use. **\n");
3399 pr_warn("** If you see this message and you are not debugging **\n");
3400 pr_warn("** the kernel, report this immediately to your vendor! **\n");
3402 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3403 pr_warn("**********************************************************\n");
3405 /* Expand the buffers to set size */
3406 tracing_update_buffers();
3408 buffers_allocated = 1;
3411 * trace_printk_init_buffers() can be called by modules.
3412 * If that happens, then we need to start cmdline recording
3413 * directly here. If the global_trace.buffer is already
3414 * allocated here, then this was called by module code.
3416 if (global_trace.array_buffer.buffer)
3417 tracing_start_cmdline_record();
3419 EXPORT_SYMBOL_GPL(trace_printk_init_buffers);
3421 void trace_printk_start_comm(void)
3423 /* Start tracing comms if trace printk is set */
3424 if (!buffers_allocated)
3426 tracing_start_cmdline_record();
3429 static void trace_printk_start_stop_comm(int enabled)
3431 if (!buffers_allocated)
3435 tracing_start_cmdline_record();
3437 tracing_stop_cmdline_record();
3441 * trace_vbprintk - write binary msg to tracing buffer
3442 * @ip: The address of the caller
3443 * @fmt: The string format to write to the buffer
3444 * @args: Arguments for @fmt
3446 int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
3448 struct trace_event_call *call = &event_bprint;
3449 struct ring_buffer_event *event;
3450 struct trace_buffer *buffer;
3451 struct trace_array *tr = &global_trace;
3452 struct bprint_entry *entry;
3453 unsigned int trace_ctx;
3457 if (unlikely(tracing_selftest_running || tracing_disabled))
3460 /* Don't pollute graph traces with trace_vprintk internals */
3461 pause_graph_tracing();
3463 trace_ctx = tracing_gen_ctx();
3464 preempt_disable_notrace();
3466 tbuffer = get_trace_buf();
3472 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
3474 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
3477 size = sizeof(*entry) + sizeof(u32) * len;
3478 buffer = tr->array_buffer.buffer;
3479 ring_buffer_nest_start(buffer);
3480 event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
3484 entry = ring_buffer_event_data(event);
3488 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
3489 if (!call_filter_check_discard(call, entry, buffer, event)) {
3490 __buffer_unlock_commit(buffer, event);
3491 ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
3495 ring_buffer_nest_end(buffer);
3500 preempt_enable_notrace();
3501 unpause_graph_tracing();
3505 EXPORT_SYMBOL_GPL(trace_vbprintk);
3509 __trace_array_vprintk(struct trace_buffer *buffer,
3510 unsigned long ip, const char *fmt, va_list args)
3512 struct trace_event_call *call = &event_print;
3513 struct ring_buffer_event *event;
3515 struct print_entry *entry;
3516 unsigned int trace_ctx;
3519 if (tracing_disabled)
3522 /* Don't pollute graph traces with trace_vprintk internals */
3523 pause_graph_tracing();
3525 trace_ctx = tracing_gen_ctx();
3526 preempt_disable_notrace();
3529 tbuffer = get_trace_buf();
3535 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
3537 size = sizeof(*entry) + len + 1;
3538 ring_buffer_nest_start(buffer);
3539 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3543 entry = ring_buffer_event_data(event);
3546 memcpy(&entry->buf, tbuffer, len + 1);
3547 if (!call_filter_check_discard(call, entry, buffer, event)) {
3548 __buffer_unlock_commit(buffer, event);
3549 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 6, NULL);
3553 ring_buffer_nest_end(buffer);
3557 preempt_enable_notrace();
3558 unpause_graph_tracing();
3564 int trace_array_vprintk(struct trace_array *tr,
3565 unsigned long ip, const char *fmt, va_list args)
3567 if (tracing_selftest_running && tr == &global_trace)
3570 return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args);
3574 * trace_array_printk - Print a message to a specific instance
3575 * @tr: The instance trace_array descriptor
3576 * @ip: The instruction pointer that this is called from.
3577 * @fmt: The format to print (printf format)
3579 * If a subsystem sets up its own instance, they have the right to
3580 * printk strings into their tracing instance buffer using this
3581 * function. Note, this function will not write into the top level
3582 * buffer (use trace_printk() for that), as writing into the top level
3583 * buffer should only have events that can be individually disabled.
3584 * trace_printk() is only used for debugging a kernel, and should not
3585 * be ever incorporated in normal use.
3587 * trace_array_printk() can be used, as it will not add noise to the
3588 * top level tracing buffer.
3590 * Note, trace_array_init_printk() must be called on @tr before this
3594 int trace_array_printk(struct trace_array *tr,
3595 unsigned long ip, const char *fmt, ...)
3603 /* This is only allowed for created instances */
3604 if (tr == &global_trace)
3607 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
3611 ret = trace_array_vprintk(tr, ip, fmt, ap);
3615 EXPORT_SYMBOL_GPL(trace_array_printk);
3618 * trace_array_init_printk - Initialize buffers for trace_array_printk()
3619 * @tr: The trace array to initialize the buffers for
3621 * As trace_array_printk() only writes into instances, they are OK to
3622 * have in the kernel (unlike trace_printk()). This needs to be called
3623 * before trace_array_printk() can be used on a trace_array.
3625 int trace_array_init_printk(struct trace_array *tr)
3630 /* This is only allowed for created instances */
3631 if (tr == &global_trace)
3634 return alloc_percpu_trace_buffer();
3636 EXPORT_SYMBOL_GPL(trace_array_init_printk);
3639 int trace_array_printk_buf(struct trace_buffer *buffer,
3640 unsigned long ip, const char *fmt, ...)
3645 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3649 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
3655 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3657 return trace_array_vprintk(&global_trace, ip, fmt, args);
3659 EXPORT_SYMBOL_GPL(trace_vprintk);
3661 static void trace_iterator_increment(struct trace_iterator *iter)
3663 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
3667 ring_buffer_iter_advance(buf_iter);
3670 static struct trace_entry *
3671 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
3672 unsigned long *lost_events)
3674 struct ring_buffer_event *event;
3675 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
3678 event = ring_buffer_iter_peek(buf_iter, ts);
3680 *lost_events = ring_buffer_iter_dropped(buf_iter) ?
3681 (unsigned long)-1 : 0;
3683 event = ring_buffer_peek(iter->array_buffer->buffer, cpu, ts,
3688 iter->ent_size = ring_buffer_event_length(event);
3689 return ring_buffer_event_data(event);
3695 static struct trace_entry *
3696 __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
3697 unsigned long *missing_events, u64 *ent_ts)
3699 struct trace_buffer *buffer = iter->array_buffer->buffer;
3700 struct trace_entry *ent, *next = NULL;
3701 unsigned long lost_events = 0, next_lost = 0;
3702 int cpu_file = iter->cpu_file;
3703 u64 next_ts = 0, ts;
3709 * If we are in a per_cpu trace file, don't bother by iterating over
3710 * all cpu and peek directly.
3712 if (cpu_file > RING_BUFFER_ALL_CPUS) {
3713 if (ring_buffer_empty_cpu(buffer, cpu_file))
3715 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
3717 *ent_cpu = cpu_file;
3722 for_each_tracing_cpu(cpu) {
3724 if (ring_buffer_empty_cpu(buffer, cpu))
3727 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
3730 * Pick the entry with the smallest timestamp:
3732 if (ent && (!next || ts < next_ts)) {
3736 next_lost = lost_events;
3737 next_size = iter->ent_size;
3741 iter->ent_size = next_size;
3744 *ent_cpu = next_cpu;
3750 *missing_events = next_lost;
3755 #define STATIC_FMT_BUF_SIZE 128
3756 static char static_fmt_buf[STATIC_FMT_BUF_SIZE];
3758 char *trace_iter_expand_format(struct trace_iterator *iter)
3763 * iter->tr is NULL when used with tp_printk, which makes
3764 * this get called where it is not safe to call krealloc().
3766 if (!iter->tr || iter->fmt == static_fmt_buf)
3769 tmp = krealloc(iter->fmt, iter->fmt_size + STATIC_FMT_BUF_SIZE,
3772 iter->fmt_size += STATIC_FMT_BUF_SIZE;
3779 /* Returns true if the string is safe to dereference from an event */
3780 static bool trace_safe_str(struct trace_iterator *iter, const char *str,
3783 unsigned long addr = (unsigned long)str;
3784 struct trace_event *trace_event;
3785 struct trace_event_call *event;
3787 /* Ignore strings with no length */
3791 /* OK if part of the event data */
3792 if ((addr >= (unsigned long)iter->ent) &&
3793 (addr < (unsigned long)iter->ent + iter->ent_size))
3796 /* OK if part of the temp seq buffer */
3797 if ((addr >= (unsigned long)iter->tmp_seq.buffer) &&
3798 (addr < (unsigned long)iter->tmp_seq.buffer + PAGE_SIZE))
3801 /* Core rodata can not be freed */
3802 if (is_kernel_rodata(addr))
3805 if (trace_is_tracepoint_string(str))
3809 * Now this could be a module event, referencing core module
3810 * data, which is OK.
3815 trace_event = ftrace_find_event(iter->ent->type);
3819 event = container_of(trace_event, struct trace_event_call, event);
3820 if ((event->flags & TRACE_EVENT_FL_DYNAMIC) || !event->module)
3823 /* Would rather have rodata, but this will suffice */
3824 if (within_module_core(addr, event->module))
3830 static const char *show_buffer(struct trace_seq *s)
3832 struct seq_buf *seq = &s->seq;
3834 seq_buf_terminate(seq);
3839 static DEFINE_STATIC_KEY_FALSE(trace_no_verify);
3841 static int test_can_verify_check(const char *fmt, ...)
3848 * The verifier is dependent on vsnprintf() modifies the va_list
3849 * passed to it, where it is sent as a reference. Some architectures
3850 * (like x86_32) passes it by value, which means that vsnprintf()
3851 * does not modify the va_list passed to it, and the verifier
3852 * would then need to be able to understand all the values that
3853 * vsnprintf can use. If it is passed by value, then the verifier
3857 vsnprintf(buf, 16, "%d", ap);
3858 ret = va_arg(ap, int);
3864 static void test_can_verify(void)
3866 if (!test_can_verify_check("%d %d", 0, 1)) {
3867 pr_info("trace event string verifier disabled\n");
3868 static_branch_inc(&trace_no_verify);
3873 * trace_check_vprintf - Check dereferenced strings while writing to the seq buffer
3874 * @iter: The iterator that holds the seq buffer and the event being printed
3875 * @fmt: The format used to print the event
3876 * @ap: The va_list holding the data to print from @fmt.
3878 * This writes the data into the @iter->seq buffer using the data from
3879 * @fmt and @ap. If the format has a %s, then the source of the string
3880 * is examined to make sure it is safe to print, otherwise it will
3881 * warn and print "[UNSAFE MEMORY]" in place of the dereferenced string
3884 void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
3887 const char *p = fmt;
3891 if (WARN_ON_ONCE(!fmt))
3894 if (static_branch_unlikely(&trace_no_verify))
3897 /* Don't bother checking when doing a ftrace_dump() */
3898 if (iter->fmt == static_fmt_buf)
3907 /* We only care about %s and variants */
3908 for (i = 0; p[i]; i++) {
3909 if (i + 1 >= iter->fmt_size) {
3911 * If we can't expand the copy buffer,
3914 if (!trace_iter_expand_format(iter))
3918 if (p[i] == '\\' && p[i+1]) {
3923 /* Need to test cases like %08.*s */
3924 for (j = 1; p[i+j]; j++) {
3925 if (isdigit(p[i+j]) ||
3928 if (p[i+j] == '*') {
3940 /* If no %s found then just print normally */
3944 /* Copy up to the %s, and print that */
3945 strncpy(iter->fmt, p, i);
3946 iter->fmt[i] = '\0';
3947 trace_seq_vprintf(&iter->seq, iter->fmt, ap);
3950 * If iter->seq is full, the above call no longer guarantees
3951 * that ap is in sync with fmt processing, and further calls
3952 * to va_arg() can return wrong positional arguments.
3954 * Ensure that ap is no longer used in this case.
3956 if (iter->seq.full) {
3962 len = va_arg(ap, int);
3964 /* The ap now points to the string data of the %s */
3965 str = va_arg(ap, const char *);
3968 * If you hit this warning, it is likely that the
3969 * trace event in question used %s on a string that
3970 * was saved at the time of the event, but may not be
3971 * around when the trace is read. Use __string(),
3972 * __assign_str() and __get_str() helpers in the TRACE_EVENT()
3973 * instead. See samples/trace_events/trace-events-sample.h
3976 if (WARN_ONCE(!trace_safe_str(iter, str, star, len),
3977 "fmt: '%s' current_buffer: '%s'",
3978 fmt, show_buffer(&iter->seq))) {
3981 /* Try to safely read the string */
3983 if (len + 1 > iter->fmt_size)
3984 len = iter->fmt_size - 1;
3987 ret = copy_from_kernel_nofault(iter->fmt, str, len);
3991 ret = strncpy_from_kernel_nofault(iter->fmt, str,
3995 trace_seq_printf(&iter->seq, "(0x%px)", str);
3997 trace_seq_printf(&iter->seq, "(0x%px:%s)",
3999 str = "[UNSAFE-MEMORY]";
4000 strcpy(iter->fmt, "%s");
4002 strncpy(iter->fmt, p + i, j + 1);
4003 iter->fmt[j+1] = '\0';
4006 trace_seq_printf(&iter->seq, iter->fmt, len, str);
4008 trace_seq_printf(&iter->seq, iter->fmt, str);
4014 trace_seq_vprintf(&iter->seq, p, ap);
4017 const char *trace_event_format(struct trace_iterator *iter, const char *fmt)
4019 const char *p, *new_fmt;
4022 if (WARN_ON_ONCE(!fmt))
4025 if (!iter->tr || iter->tr->trace_flags & TRACE_ITER_HASH_PTR)
4029 new_fmt = q = iter->fmt;
4031 if (unlikely(q - new_fmt + 3 > iter->fmt_size)) {
4032 if (!trace_iter_expand_format(iter))
4035 q += iter->fmt - new_fmt;
4036 new_fmt = iter->fmt;
4041 /* Replace %p with %px */
4045 } else if (p[0] == 'p' && !isalnum(p[1])) {
4056 #define STATIC_TEMP_BUF_SIZE 128
4057 static char static_temp_buf[STATIC_TEMP_BUF_SIZE] __aligned(4);
4059 /* Find the next real entry, without updating the iterator itself */
4060 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
4061 int *ent_cpu, u64 *ent_ts)
4063 /* __find_next_entry will reset ent_size */
4064 int ent_size = iter->ent_size;
4065 struct trace_entry *entry;
4068 * If called from ftrace_dump(), then the iter->temp buffer
4069 * will be the static_temp_buf and not created from kmalloc.
4070 * If the entry size is greater than the buffer, we can
4071 * not save it. Just return NULL in that case. This is only
4072 * used to add markers when two consecutive events' time
4073 * stamps have a large delta. See trace_print_lat_context()
4075 if (iter->temp == static_temp_buf &&
4076 STATIC_TEMP_BUF_SIZE < ent_size)
4080 * The __find_next_entry() may call peek_next_entry(), which may
4081 * call ring_buffer_peek() that may make the contents of iter->ent
4082 * undefined. Need to copy iter->ent now.
4084 if (iter->ent && iter->ent != iter->temp) {
4085 if ((!iter->temp || iter->temp_size < iter->ent_size) &&
4086 !WARN_ON_ONCE(iter->temp == static_temp_buf)) {
4088 temp = kmalloc(iter->ent_size, GFP_KERNEL);
4093 iter->temp_size = iter->ent_size;
4095 memcpy(iter->temp, iter->ent, iter->ent_size);
4096 iter->ent = iter->temp;
4098 entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);
4099 /* Put back the original ent_size */
4100 iter->ent_size = ent_size;
4105 /* Find the next real entry, and increment the iterator to the next entry */
4106 void *trace_find_next_entry_inc(struct trace_iterator *iter)
4108 iter->ent = __find_next_entry(iter, &iter->cpu,
4109 &iter->lost_events, &iter->ts);
4112 trace_iterator_increment(iter);
4114 return iter->ent ? iter : NULL;
4117 static void trace_consume(struct trace_iterator *iter)
4119 ring_buffer_consume(iter->array_buffer->buffer, iter->cpu, &iter->ts,
4120 &iter->lost_events);
4123 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
4125 struct trace_iterator *iter = m->private;
4129 WARN_ON_ONCE(iter->leftover);
4133 /* can't go backwards */
4138 ent = trace_find_next_entry_inc(iter);
4142 while (ent && iter->idx < i)
4143 ent = trace_find_next_entry_inc(iter);
4150 void tracing_iter_reset(struct trace_iterator *iter, int cpu)
4152 struct ring_buffer_iter *buf_iter;
4153 unsigned long entries = 0;
4156 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = 0;
4158 buf_iter = trace_buffer_iter(iter, cpu);
4162 ring_buffer_iter_reset(buf_iter);
4165 * We could have the case with the max latency tracers
4166 * that a reset never took place on a cpu. This is evident
4167 * by the timestamp being before the start of the buffer.
4169 while (ring_buffer_iter_peek(buf_iter, &ts)) {
4170 if (ts >= iter->array_buffer->time_start)
4173 ring_buffer_iter_advance(buf_iter);
4176 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = entries;
4180 * The current tracer is copied to avoid a global locking
4183 static void *s_start(struct seq_file *m, loff_t *pos)
4185 struct trace_iterator *iter = m->private;
4186 struct trace_array *tr = iter->tr;
4187 int cpu_file = iter->cpu_file;
4192 mutex_lock(&trace_types_lock);
4193 if (unlikely(tr->current_trace != iter->trace)) {
4194 /* Close iter->trace before switching to the new current tracer */
4195 if (iter->trace->close)
4196 iter->trace->close(iter);
4197 iter->trace = tr->current_trace;
4198 /* Reopen the new current tracer */
4199 if (iter->trace->open)
4200 iter->trace->open(iter);
4202 mutex_unlock(&trace_types_lock);
4204 #ifdef CONFIG_TRACER_MAX_TRACE
4205 if (iter->snapshot && iter->trace->use_max_tr)
4206 return ERR_PTR(-EBUSY);
4209 if (*pos != iter->pos) {
4214 if (cpu_file == RING_BUFFER_ALL_CPUS) {
4215 for_each_tracing_cpu(cpu)
4216 tracing_iter_reset(iter, cpu);
4218 tracing_iter_reset(iter, cpu_file);
4221 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
4226 * If we overflowed the seq_file before, then we want
4227 * to just reuse the trace_seq buffer again.
4233 p = s_next(m, p, &l);
4237 trace_event_read_lock();
4238 trace_access_lock(cpu_file);
4242 static void s_stop(struct seq_file *m, void *p)
4244 struct trace_iterator *iter = m->private;
4246 #ifdef CONFIG_TRACER_MAX_TRACE
4247 if (iter->snapshot && iter->trace->use_max_tr)
4251 trace_access_unlock(iter->cpu_file);
4252 trace_event_read_unlock();
4256 get_total_entries_cpu(struct array_buffer *buf, unsigned long *total,
4257 unsigned long *entries, int cpu)
4259 unsigned long count;
4261 count = ring_buffer_entries_cpu(buf->buffer, cpu);
4263 * If this buffer has skipped entries, then we hold all
4264 * entries for the trace and we need to ignore the
4265 * ones before the time stamp.
4267 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
4268 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
4269 /* total is the same as the entries */
4273 ring_buffer_overrun_cpu(buf->buffer, cpu);
4278 get_total_entries(struct array_buffer *buf,
4279 unsigned long *total, unsigned long *entries)
4287 for_each_tracing_cpu(cpu) {
4288 get_total_entries_cpu(buf, &t, &e, cpu);
4294 unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
4296 unsigned long total, entries;
4301 get_total_entries_cpu(&tr->array_buffer, &total, &entries, cpu);
4306 unsigned long trace_total_entries(struct trace_array *tr)
4308 unsigned long total, entries;
4313 get_total_entries(&tr->array_buffer, &total, &entries);
4318 static void print_lat_help_header(struct seq_file *m)
4320 seq_puts(m, "# _------=> CPU# \n"
4321 "# / _-----=> irqs-off/BH-disabled\n"
4322 "# | / _----=> need-resched \n"
4323 "# || / _---=> hardirq/softirq \n"
4324 "# ||| / _--=> preempt-depth \n"
4325 "# |||| / _-=> migrate-disable \n"
4326 "# ||||| / delay \n"
4327 "# cmd pid |||||| time | caller \n"
4328 "# \\ / |||||| \\ | / \n");
4331 static void print_event_info(struct array_buffer *buf, struct seq_file *m)
4333 unsigned long total;
4334 unsigned long entries;
4336 get_total_entries(buf, &total, &entries);
4337 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
4338 entries, total, num_online_cpus());
4342 static void print_func_help_header(struct array_buffer *buf, struct seq_file *m,
4345 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4347 print_event_info(buf, m);
4349 seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? " TGID " : "");
4350 seq_printf(m, "# | | %s | | |\n", tgid ? " | " : "");
4353 static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file *m,
4356 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4357 static const char space[] = " ";
4358 int prec = tgid ? 12 : 2;
4360 print_event_info(buf, m);
4362 seq_printf(m, "# %.*s _-----=> irqs-off/BH-disabled\n", prec, space);
4363 seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space);
4364 seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space);
4365 seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space);
4366 seq_printf(m, "# %.*s||| / _-=> migrate-disable\n", prec, space);
4367 seq_printf(m, "# %.*s|||| / delay\n", prec, space);
4368 seq_printf(m, "# TASK-PID %.*s CPU# ||||| TIMESTAMP FUNCTION\n", prec, " TGID ");
4369 seq_printf(m, "# | | %.*s | ||||| | |\n", prec, " | ");
4373 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
4375 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
4376 struct array_buffer *buf = iter->array_buffer;
4377 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
4378 struct tracer *type = iter->trace;
4379 unsigned long entries;
4380 unsigned long total;
4381 const char *name = type->name;
4383 get_total_entries(buf, &total, &entries);
4385 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
4387 seq_puts(m, "# -----------------------------------"
4388 "---------------------------------\n");
4389 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
4390 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
4391 nsecs_to_usecs(data->saved_latency),
4395 preempt_model_none() ? "server" :
4396 preempt_model_voluntary() ? "desktop" :
4397 preempt_model_full() ? "preempt" :
4398 preempt_model_rt() ? "preempt_rt" :
4400 /* These are reserved for later use */
4403 seq_printf(m, " #P:%d)\n", num_online_cpus());
4407 seq_puts(m, "# -----------------\n");
4408 seq_printf(m, "# | task: %.16s-%d "
4409 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
4410 data->comm, data->pid,
4411 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
4412 data->policy, data->rt_priority);
4413 seq_puts(m, "# -----------------\n");
4415 if (data->critical_start) {
4416 seq_puts(m, "# => started at: ");
4417 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
4418 trace_print_seq(m, &iter->seq);
4419 seq_puts(m, "\n# => ended at: ");
4420 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
4421 trace_print_seq(m, &iter->seq);
4422 seq_puts(m, "\n#\n");
4428 static void test_cpu_buff_start(struct trace_iterator *iter)
4430 struct trace_seq *s = &iter->seq;
4431 struct trace_array *tr = iter->tr;
4433 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
4436 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
4439 if (cpumask_available(iter->started) &&
4440 cpumask_test_cpu(iter->cpu, iter->started))
4443 if (per_cpu_ptr(iter->array_buffer->data, iter->cpu)->skipped_entries)
4446 if (cpumask_available(iter->started))
4447 cpumask_set_cpu(iter->cpu, iter->started);
4449 /* Don't print started cpu buffer for the first entry of the trace */
4451 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
4455 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
4457 struct trace_array *tr = iter->tr;
4458 struct trace_seq *s = &iter->seq;
4459 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
4460 struct trace_entry *entry;
4461 struct trace_event *event;
4465 test_cpu_buff_start(iter);
4467 event = ftrace_find_event(entry->type);
4469 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4470 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4471 trace_print_lat_context(iter);
4473 trace_print_context(iter);
4476 if (trace_seq_has_overflowed(s))
4477 return TRACE_TYPE_PARTIAL_LINE;
4480 if (tr->trace_flags & TRACE_ITER_FIELDS)
4481 return print_event_fields(iter, event);
4482 return event->funcs->trace(iter, sym_flags, event);
4485 trace_seq_printf(s, "Unknown type %d\n", entry->type);
4487 return trace_handle_return(s);
4490 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
4492 struct trace_array *tr = iter->tr;
4493 struct trace_seq *s = &iter->seq;
4494 struct trace_entry *entry;
4495 struct trace_event *event;
4499 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
4500 trace_seq_printf(s, "%d %d %llu ",
4501 entry->pid, iter->cpu, iter->ts);
4503 if (trace_seq_has_overflowed(s))
4504 return TRACE_TYPE_PARTIAL_LINE;
4506 event = ftrace_find_event(entry->type);
4508 return event->funcs->raw(iter, 0, event);
4510 trace_seq_printf(s, "%d ?\n", entry->type);
4512 return trace_handle_return(s);
4515 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
4517 struct trace_array *tr = iter->tr;
4518 struct trace_seq *s = &iter->seq;
4519 unsigned char newline = '\n';
4520 struct trace_entry *entry;
4521 struct trace_event *event;
4525 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4526 SEQ_PUT_HEX_FIELD(s, entry->pid);
4527 SEQ_PUT_HEX_FIELD(s, iter->cpu);
4528 SEQ_PUT_HEX_FIELD(s, iter->ts);
4529 if (trace_seq_has_overflowed(s))
4530 return TRACE_TYPE_PARTIAL_LINE;
4533 event = ftrace_find_event(entry->type);
4535 enum print_line_t ret = event->funcs->hex(iter, 0, event);
4536 if (ret != TRACE_TYPE_HANDLED)
4540 SEQ_PUT_FIELD(s, newline);
4542 return trace_handle_return(s);
4545 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
4547 struct trace_array *tr = iter->tr;
4548 struct trace_seq *s = &iter->seq;
4549 struct trace_entry *entry;
4550 struct trace_event *event;
4554 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4555 SEQ_PUT_FIELD(s, entry->pid);
4556 SEQ_PUT_FIELD(s, iter->cpu);
4557 SEQ_PUT_FIELD(s, iter->ts);
4558 if (trace_seq_has_overflowed(s))
4559 return TRACE_TYPE_PARTIAL_LINE;
4562 event = ftrace_find_event(entry->type);
4563 return event ? event->funcs->binary(iter, 0, event) :
4567 int trace_empty(struct trace_iterator *iter)
4569 struct ring_buffer_iter *buf_iter;
4572 /* If we are looking at one CPU buffer, only check that one */
4573 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4574 cpu = iter->cpu_file;
4575 buf_iter = trace_buffer_iter(iter, cpu);
4577 if (!ring_buffer_iter_empty(buf_iter))
4580 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4586 for_each_tracing_cpu(cpu) {
4587 buf_iter = trace_buffer_iter(iter, cpu);
4589 if (!ring_buffer_iter_empty(buf_iter))
4592 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4600 /* Called with trace_event_read_lock() held. */
4601 enum print_line_t print_trace_line(struct trace_iterator *iter)
4603 struct trace_array *tr = iter->tr;
4604 unsigned long trace_flags = tr->trace_flags;
4605 enum print_line_t ret;
4607 if (iter->lost_events) {
4608 if (iter->lost_events == (unsigned long)-1)
4609 trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n",
4612 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
4613 iter->cpu, iter->lost_events);
4614 if (trace_seq_has_overflowed(&iter->seq))
4615 return TRACE_TYPE_PARTIAL_LINE;
4618 if (iter->trace && iter->trace->print_line) {
4619 ret = iter->trace->print_line(iter);
4620 if (ret != TRACE_TYPE_UNHANDLED)
4624 if (iter->ent->type == TRACE_BPUTS &&
4625 trace_flags & TRACE_ITER_PRINTK &&
4626 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4627 return trace_print_bputs_msg_only(iter);
4629 if (iter->ent->type == TRACE_BPRINT &&
4630 trace_flags & TRACE_ITER_PRINTK &&
4631 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4632 return trace_print_bprintk_msg_only(iter);
4634 if (iter->ent->type == TRACE_PRINT &&
4635 trace_flags & TRACE_ITER_PRINTK &&
4636 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4637 return trace_print_printk_msg_only(iter);
4639 if (trace_flags & TRACE_ITER_BIN)
4640 return print_bin_fmt(iter);
4642 if (trace_flags & TRACE_ITER_HEX)
4643 return print_hex_fmt(iter);
4645 if (trace_flags & TRACE_ITER_RAW)
4646 return print_raw_fmt(iter);
4648 return print_trace_fmt(iter);
4651 void trace_latency_header(struct seq_file *m)
4653 struct trace_iterator *iter = m->private;
4654 struct trace_array *tr = iter->tr;
4656 /* print nothing if the buffers are empty */
4657 if (trace_empty(iter))
4660 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4661 print_trace_header(m, iter);
4663 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
4664 print_lat_help_header(m);
4667 void trace_default_header(struct seq_file *m)
4669 struct trace_iterator *iter = m->private;
4670 struct trace_array *tr = iter->tr;
4671 unsigned long trace_flags = tr->trace_flags;
4673 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
4676 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
4677 /* print nothing if the buffers are empty */
4678 if (trace_empty(iter))
4680 print_trace_header(m, iter);
4681 if (!(trace_flags & TRACE_ITER_VERBOSE))
4682 print_lat_help_header(m);
4684 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
4685 if (trace_flags & TRACE_ITER_IRQ_INFO)
4686 print_func_help_header_irq(iter->array_buffer,
4689 print_func_help_header(iter->array_buffer, m,
4695 static void test_ftrace_alive(struct seq_file *m)
4697 if (!ftrace_is_dead())
4699 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
4700 "# MAY BE MISSING FUNCTION EVENTS\n");
4703 #ifdef CONFIG_TRACER_MAX_TRACE
4704 static void show_snapshot_main_help(struct seq_file *m)
4706 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
4707 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4708 "# Takes a snapshot of the main buffer.\n"
4709 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
4710 "# (Doesn't have to be '2' works with any number that\n"
4711 "# is not a '0' or '1')\n");
4714 static void show_snapshot_percpu_help(struct seq_file *m)
4716 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
4717 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
4718 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4719 "# Takes a snapshot of the main buffer for this cpu.\n");
4721 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
4722 "# Must use main snapshot file to allocate.\n");
4724 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
4725 "# (Doesn't have to be '2' works with any number that\n"
4726 "# is not a '0' or '1')\n");
4729 static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
4731 if (iter->tr->allocated_snapshot)
4732 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
4734 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
4736 seq_puts(m, "# Snapshot commands:\n");
4737 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4738 show_snapshot_main_help(m);
4740 show_snapshot_percpu_help(m);
4743 /* Should never be called */
4744 static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
4747 static int s_show(struct seq_file *m, void *v)
4749 struct trace_iterator *iter = v;
4752 if (iter->ent == NULL) {
4754 seq_printf(m, "# tracer: %s\n", iter->trace->name);
4756 test_ftrace_alive(m);
4758 if (iter->snapshot && trace_empty(iter))
4759 print_snapshot_help(m, iter);
4760 else if (iter->trace && iter->trace->print_header)
4761 iter->trace->print_header(m);
4763 trace_default_header(m);
4765 } else if (iter->leftover) {
4767 * If we filled the seq_file buffer earlier, we
4768 * want to just show it now.
4770 ret = trace_print_seq(m, &iter->seq);
4772 /* ret should this time be zero, but you never know */
4773 iter->leftover = ret;
4776 print_trace_line(iter);
4777 ret = trace_print_seq(m, &iter->seq);
4779 * If we overflow the seq_file buffer, then it will
4780 * ask us for this data again at start up.
4782 * ret is 0 if seq_file write succeeded.
4785 iter->leftover = ret;
4792 * Should be used after trace_array_get(), trace_types_lock
4793 * ensures that i_cdev was already initialized.
4795 static inline int tracing_get_cpu(struct inode *inode)
4797 if (inode->i_cdev) /* See trace_create_cpu_file() */
4798 return (long)inode->i_cdev - 1;
4799 return RING_BUFFER_ALL_CPUS;
4802 static const struct seq_operations tracer_seq_ops = {
4810 * Note, as iter itself can be allocated and freed in different
4811 * ways, this function is only used to free its content, and not
4812 * the iterator itself. The only requirement to all the allocations
4813 * is that it must zero all fields (kzalloc), as freeing works with
4814 * ethier allocated content or NULL.
4816 static void free_trace_iter_content(struct trace_iterator *iter)
4818 /* The fmt is either NULL, allocated or points to static_fmt_buf */
4819 if (iter->fmt != static_fmt_buf)
4823 kfree(iter->buffer_iter);
4824 mutex_destroy(&iter->mutex);
4825 free_cpumask_var(iter->started);
4828 static struct trace_iterator *
4829 __tracing_open(struct inode *inode, struct file *file, bool snapshot)
4831 struct trace_array *tr = inode->i_private;
4832 struct trace_iterator *iter;
4835 if (tracing_disabled)
4836 return ERR_PTR(-ENODEV);
4838 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
4840 return ERR_PTR(-ENOMEM);
4842 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
4844 if (!iter->buffer_iter)
4848 * trace_find_next_entry() may need to save off iter->ent.
4849 * It will place it into the iter->temp buffer. As most
4850 * events are less than 128, allocate a buffer of that size.
4851 * If one is greater, then trace_find_next_entry() will
4852 * allocate a new buffer to adjust for the bigger iter->ent.
4853 * It's not critical if it fails to get allocated here.
4855 iter->temp = kmalloc(128, GFP_KERNEL);
4857 iter->temp_size = 128;
4860 * trace_event_printf() may need to modify given format
4861 * string to replace %p with %px so that it shows real address
4862 * instead of hash value. However, that is only for the event
4863 * tracing, other tracer may not need. Defer the allocation
4864 * until it is needed.
4869 mutex_lock(&trace_types_lock);
4870 iter->trace = tr->current_trace;
4872 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
4877 #ifdef CONFIG_TRACER_MAX_TRACE
4878 /* Currently only the top directory has a snapshot */
4879 if (tr->current_trace->print_max || snapshot)
4880 iter->array_buffer = &tr->max_buffer;
4883 iter->array_buffer = &tr->array_buffer;
4884 iter->snapshot = snapshot;
4886 iter->cpu_file = tracing_get_cpu(inode);
4887 mutex_init(&iter->mutex);
4889 /* Notify the tracer early; before we stop tracing. */
4890 if (iter->trace->open)
4891 iter->trace->open(iter);
4893 /* Annotate start of buffers if we had overruns */
4894 if (ring_buffer_overruns(iter->array_buffer->buffer))
4895 iter->iter_flags |= TRACE_FILE_ANNOTATE;
4897 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4898 if (trace_clocks[tr->clock_id].in_ns)
4899 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4902 * If pause-on-trace is enabled, then stop the trace while
4903 * dumping, unless this is the "snapshot" file
4905 if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
4906 tracing_stop_tr(tr);
4908 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
4909 for_each_tracing_cpu(cpu) {
4910 iter->buffer_iter[cpu] =
4911 ring_buffer_read_prepare(iter->array_buffer->buffer,
4914 ring_buffer_read_prepare_sync();
4915 for_each_tracing_cpu(cpu) {
4916 ring_buffer_read_start(iter->buffer_iter[cpu]);
4917 tracing_iter_reset(iter, cpu);
4920 cpu = iter->cpu_file;
4921 iter->buffer_iter[cpu] =
4922 ring_buffer_read_prepare(iter->array_buffer->buffer,
4924 ring_buffer_read_prepare_sync();
4925 ring_buffer_read_start(iter->buffer_iter[cpu]);
4926 tracing_iter_reset(iter, cpu);
4929 mutex_unlock(&trace_types_lock);
4934 mutex_unlock(&trace_types_lock);
4935 free_trace_iter_content(iter);
4937 seq_release_private(inode, file);
4938 return ERR_PTR(-ENOMEM);
4941 int tracing_open_generic(struct inode *inode, struct file *filp)
4945 ret = tracing_check_open_get_tr(NULL);
4949 filp->private_data = inode->i_private;
4953 bool tracing_is_disabled(void)
4955 return (tracing_disabled) ? true: false;
4959 * Open and update trace_array ref count.
4960 * Must have the current trace_array passed to it.
4962 int tracing_open_generic_tr(struct inode *inode, struct file *filp)
4964 struct trace_array *tr = inode->i_private;
4967 ret = tracing_check_open_get_tr(tr);
4971 filp->private_data = inode->i_private;
4977 * The private pointer of the inode is the trace_event_file.
4978 * Update the tr ref count associated to it.
4980 int tracing_open_file_tr(struct inode *inode, struct file *filp)
4982 struct trace_event_file *file = inode->i_private;
4985 ret = tracing_check_open_get_tr(file->tr);
4989 mutex_lock(&event_mutex);
4991 /* Fail if the file is marked for removal */
4992 if (file->flags & EVENT_FILE_FL_FREED) {
4993 trace_array_put(file->tr);
4996 event_file_get(file);
4999 mutex_unlock(&event_mutex);
5003 filp->private_data = inode->i_private;
5008 int tracing_release_file_tr(struct inode *inode, struct file *filp)
5010 struct trace_event_file *file = inode->i_private;
5012 trace_array_put(file->tr);
5013 event_file_put(file);
5018 static int tracing_mark_open(struct inode *inode, struct file *filp)
5020 stream_open(inode, filp);
5021 return tracing_open_generic_tr(inode, filp);
5024 static int tracing_release(struct inode *inode, struct file *file)
5026 struct trace_array *tr = inode->i_private;
5027 struct seq_file *m = file->private_data;
5028 struct trace_iterator *iter;
5031 if (!(file->f_mode & FMODE_READ)) {
5032 trace_array_put(tr);
5036 /* Writes do not use seq_file */
5038 mutex_lock(&trace_types_lock);
5040 for_each_tracing_cpu(cpu) {
5041 if (iter->buffer_iter[cpu])
5042 ring_buffer_read_finish(iter->buffer_iter[cpu]);
5045 if (iter->trace && iter->trace->close)
5046 iter->trace->close(iter);
5048 if (!iter->snapshot && tr->stop_count)
5049 /* reenable tracing if it was previously enabled */
5050 tracing_start_tr(tr);
5052 __trace_array_put(tr);
5054 mutex_unlock(&trace_types_lock);
5056 free_trace_iter_content(iter);
5057 seq_release_private(inode, file);
5062 static int tracing_release_generic_tr(struct inode *inode, struct file *file)
5064 struct trace_array *tr = inode->i_private;
5066 trace_array_put(tr);
5070 static int tracing_single_release_tr(struct inode *inode, struct file *file)
5072 struct trace_array *tr = inode->i_private;
5074 trace_array_put(tr);
5076 return single_release(inode, file);
5079 static int tracing_open(struct inode *inode, struct file *file)
5081 struct trace_array *tr = inode->i_private;
5082 struct trace_iterator *iter;
5085 ret = tracing_check_open_get_tr(tr);
5089 /* If this file was open for write, then erase contents */
5090 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
5091 int cpu = tracing_get_cpu(inode);
5092 struct array_buffer *trace_buf = &tr->array_buffer;
5094 #ifdef CONFIG_TRACER_MAX_TRACE
5095 if (tr->current_trace->print_max)
5096 trace_buf = &tr->max_buffer;
5099 if (cpu == RING_BUFFER_ALL_CPUS)
5100 tracing_reset_online_cpus(trace_buf);
5102 tracing_reset_cpu(trace_buf, cpu);
5105 if (file->f_mode & FMODE_READ) {
5106 iter = __tracing_open(inode, file, false);
5108 ret = PTR_ERR(iter);
5109 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
5110 iter->iter_flags |= TRACE_FILE_LAT_FMT;
5114 trace_array_put(tr);
5120 * Some tracers are not suitable for instance buffers.
5121 * A tracer is always available for the global array (toplevel)
5122 * or if it explicitly states that it is.
5125 trace_ok_for_array(struct tracer *t, struct trace_array *tr)
5127 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
5130 /* Find the next tracer that this trace array may use */
5131 static struct tracer *
5132 get_tracer_for_array(struct trace_array *tr, struct tracer *t)
5134 while (t && !trace_ok_for_array(t, tr))
5141 t_next(struct seq_file *m, void *v, loff_t *pos)
5143 struct trace_array *tr = m->private;
5144 struct tracer *t = v;
5149 t = get_tracer_for_array(tr, t->next);
5154 static void *t_start(struct seq_file *m, loff_t *pos)
5156 struct trace_array *tr = m->private;
5160 mutex_lock(&trace_types_lock);
5162 t = get_tracer_for_array(tr, trace_types);
5163 for (; t && l < *pos; t = t_next(m, t, &l))
5169 static void t_stop(struct seq_file *m, void *p)
5171 mutex_unlock(&trace_types_lock);
5174 static int t_show(struct seq_file *m, void *v)
5176 struct tracer *t = v;
5181 seq_puts(m, t->name);
5190 static const struct seq_operations show_traces_seq_ops = {
5197 static int show_traces_open(struct inode *inode, struct file *file)
5199 struct trace_array *tr = inode->i_private;
5203 ret = tracing_check_open_get_tr(tr);
5207 ret = seq_open(file, &show_traces_seq_ops);
5209 trace_array_put(tr);
5213 m = file->private_data;
5219 static int show_traces_release(struct inode *inode, struct file *file)
5221 struct trace_array *tr = inode->i_private;
5223 trace_array_put(tr);
5224 return seq_release(inode, file);
5228 tracing_write_stub(struct file *filp, const char __user *ubuf,
5229 size_t count, loff_t *ppos)
5234 loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
5238 if (file->f_mode & FMODE_READ)
5239 ret = seq_lseek(file, offset, whence);
5241 file->f_pos = ret = 0;
5246 static const struct file_operations tracing_fops = {
5247 .open = tracing_open,
5249 .read_iter = seq_read_iter,
5250 .splice_read = copy_splice_read,
5251 .write = tracing_write_stub,
5252 .llseek = tracing_lseek,
5253 .release = tracing_release,
5256 static const struct file_operations show_traces_fops = {
5257 .open = show_traces_open,
5259 .llseek = seq_lseek,
5260 .release = show_traces_release,
5264 tracing_cpumask_read(struct file *filp, char __user *ubuf,
5265 size_t count, loff_t *ppos)
5267 struct trace_array *tr = file_inode(filp)->i_private;
5271 len = snprintf(NULL, 0, "%*pb\n",
5272 cpumask_pr_args(tr->tracing_cpumask)) + 1;
5273 mask_str = kmalloc(len, GFP_KERNEL);
5277 len = snprintf(mask_str, len, "%*pb\n",
5278 cpumask_pr_args(tr->tracing_cpumask));
5283 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
5291 int tracing_set_cpumask(struct trace_array *tr,
5292 cpumask_var_t tracing_cpumask_new)
5299 local_irq_disable();
5300 arch_spin_lock(&tr->max_lock);
5301 for_each_tracing_cpu(cpu) {
5303 * Increase/decrease the disabled counter if we are
5304 * about to flip a bit in the cpumask:
5306 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5307 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5308 atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5309 ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
5310 #ifdef CONFIG_TRACER_MAX_TRACE
5311 ring_buffer_record_disable_cpu(tr->max_buffer.buffer, cpu);
5314 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5315 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5316 atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5317 ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
5318 #ifdef CONFIG_TRACER_MAX_TRACE
5319 ring_buffer_record_enable_cpu(tr->max_buffer.buffer, cpu);
5323 arch_spin_unlock(&tr->max_lock);
5326 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
5332 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
5333 size_t count, loff_t *ppos)
5335 struct trace_array *tr = file_inode(filp)->i_private;
5336 cpumask_var_t tracing_cpumask_new;
5339 if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
5342 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
5346 err = tracing_set_cpumask(tr, tracing_cpumask_new);
5350 free_cpumask_var(tracing_cpumask_new);
5355 free_cpumask_var(tracing_cpumask_new);
5360 static const struct file_operations tracing_cpumask_fops = {
5361 .open = tracing_open_generic_tr,
5362 .read = tracing_cpumask_read,
5363 .write = tracing_cpumask_write,
5364 .release = tracing_release_generic_tr,
5365 .llseek = generic_file_llseek,
5368 static int tracing_trace_options_show(struct seq_file *m, void *v)
5370 struct tracer_opt *trace_opts;
5371 struct trace_array *tr = m->private;
5375 mutex_lock(&trace_types_lock);
5376 tracer_flags = tr->current_trace->flags->val;
5377 trace_opts = tr->current_trace->flags->opts;
5379 for (i = 0; trace_options[i]; i++) {
5380 if (tr->trace_flags & (1 << i))
5381 seq_printf(m, "%s\n", trace_options[i]);
5383 seq_printf(m, "no%s\n", trace_options[i]);
5386 for (i = 0; trace_opts[i].name; i++) {
5387 if (tracer_flags & trace_opts[i].bit)
5388 seq_printf(m, "%s\n", trace_opts[i].name);
5390 seq_printf(m, "no%s\n", trace_opts[i].name);
5392 mutex_unlock(&trace_types_lock);
5397 static int __set_tracer_option(struct trace_array *tr,
5398 struct tracer_flags *tracer_flags,
5399 struct tracer_opt *opts, int neg)
5401 struct tracer *trace = tracer_flags->trace;
5404 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
5409 tracer_flags->val &= ~opts->bit;
5411 tracer_flags->val |= opts->bit;
5415 /* Try to assign a tracer specific option */
5416 static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
5418 struct tracer *trace = tr->current_trace;
5419 struct tracer_flags *tracer_flags = trace->flags;
5420 struct tracer_opt *opts = NULL;
5423 for (i = 0; tracer_flags->opts[i].name; i++) {
5424 opts = &tracer_flags->opts[i];
5426 if (strcmp(cmp, opts->name) == 0)
5427 return __set_tracer_option(tr, trace->flags, opts, neg);
5433 /* Some tracers require overwrite to stay enabled */
5434 int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
5436 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
5442 int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
5446 if ((mask == TRACE_ITER_RECORD_TGID) ||
5447 (mask == TRACE_ITER_RECORD_CMD))
5448 lockdep_assert_held(&event_mutex);
5450 /* do nothing if flag is already set */
5451 if (!!(tr->trace_flags & mask) == !!enabled)
5454 /* Give the tracer a chance to approve the change */
5455 if (tr->current_trace->flag_changed)
5456 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
5460 tr->trace_flags |= mask;
5462 tr->trace_flags &= ~mask;
5464 if (mask == TRACE_ITER_RECORD_CMD)
5465 trace_event_enable_cmd_record(enabled);
5467 if (mask == TRACE_ITER_RECORD_TGID) {
5469 tgid_map_max = pid_max;
5470 map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
5474 * Pairs with smp_load_acquire() in
5475 * trace_find_tgid_ptr() to ensure that if it observes
5476 * the tgid_map we just allocated then it also observes
5477 * the corresponding tgid_map_max value.
5479 smp_store_release(&tgid_map, map);
5482 tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
5486 trace_event_enable_tgid_record(enabled);
5489 if (mask == TRACE_ITER_EVENT_FORK)
5490 trace_event_follow_fork(tr, enabled);
5492 if (mask == TRACE_ITER_FUNC_FORK)
5493 ftrace_pid_follow_fork(tr, enabled);
5495 if (mask == TRACE_ITER_OVERWRITE) {
5496 ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled);
5497 #ifdef CONFIG_TRACER_MAX_TRACE
5498 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
5502 if (mask == TRACE_ITER_PRINTK) {
5503 trace_printk_start_stop_comm(enabled);
5504 trace_printk_control(enabled);
5510 int trace_set_options(struct trace_array *tr, char *option)
5515 size_t orig_len = strlen(option);
5518 cmp = strstrip(option);
5520 len = str_has_prefix(cmp, "no");
5526 mutex_lock(&event_mutex);
5527 mutex_lock(&trace_types_lock);
5529 ret = match_string(trace_options, -1, cmp);
5530 /* If no option could be set, test the specific tracer options */
5532 ret = set_tracer_option(tr, cmp, neg);
5534 ret = set_tracer_flag(tr, 1 << ret, !neg);
5536 mutex_unlock(&trace_types_lock);
5537 mutex_unlock(&event_mutex);
5540 * If the first trailing whitespace is replaced with '\0' by strstrip,
5541 * turn it back into a space.
5543 if (orig_len > strlen(option))
5544 option[strlen(option)] = ' ';
5549 static void __init apply_trace_boot_options(void)
5551 char *buf = trace_boot_options_buf;
5555 option = strsep(&buf, ",");
5561 trace_set_options(&global_trace, option);
5563 /* Put back the comma to allow this to be called again */
5570 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
5571 size_t cnt, loff_t *ppos)
5573 struct seq_file *m = filp->private_data;
5574 struct trace_array *tr = m->private;
5578 if (cnt >= sizeof(buf))
5581 if (copy_from_user(buf, ubuf, cnt))
5586 ret = trace_set_options(tr, buf);
5595 static int tracing_trace_options_open(struct inode *inode, struct file *file)
5597 struct trace_array *tr = inode->i_private;
5600 ret = tracing_check_open_get_tr(tr);
5604 ret = single_open(file, tracing_trace_options_show, inode->i_private);
5606 trace_array_put(tr);
5611 static const struct file_operations tracing_iter_fops = {
5612 .open = tracing_trace_options_open,
5614 .llseek = seq_lseek,
5615 .release = tracing_single_release_tr,
5616 .write = tracing_trace_options_write,
5619 static const char readme_msg[] =
5620 "tracing mini-HOWTO:\n\n"
5621 "# echo 0 > tracing_on : quick way to disable tracing\n"
5622 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
5623 " Important files:\n"
5624 " trace\t\t\t- The static contents of the buffer\n"
5625 "\t\t\t To clear the buffer write into this file: echo > trace\n"
5626 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
5627 " current_tracer\t- function and latency tracers\n"
5628 " available_tracers\t- list of configured tracers for current_tracer\n"
5629 " error_log\t- error log for failed commands (that support it)\n"
5630 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
5631 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
5632 " trace_clock\t\t- change the clock used to order events\n"
5633 " local: Per cpu clock but may not be synced across CPUs\n"
5634 " global: Synced across CPUs but slows tracing down.\n"
5635 " counter: Not a clock, but just an increment\n"
5636 " uptime: Jiffy counter from time of boot\n"
5637 " perf: Same clock that perf events use\n"
5638 #ifdef CONFIG_X86_64
5639 " x86-tsc: TSC cycle counter\n"
5641 "\n timestamp_mode\t- view the mode used to timestamp events\n"
5642 " delta: Delta difference against a buffer-wide timestamp\n"
5643 " absolute: Absolute (standalone) timestamp\n"
5644 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
5645 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
5646 " tracing_cpumask\t- Limit which CPUs to trace\n"
5647 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
5648 "\t\t\t Remove sub-buffer with rmdir\n"
5649 " trace_options\t\t- Set format or modify how tracing happens\n"
5650 "\t\t\t Disable an option by prefixing 'no' to the\n"
5651 "\t\t\t option name\n"
5652 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
5653 #ifdef CONFIG_DYNAMIC_FTRACE
5654 "\n available_filter_functions - list of functions that can be filtered on\n"
5655 " set_ftrace_filter\t- echo function name in here to only trace these\n"
5656 "\t\t\t functions\n"
5657 "\t accepts: func_full_name or glob-matching-pattern\n"
5658 "\t modules: Can select a group via module\n"
5659 "\t Format: :mod:<module-name>\n"
5660 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
5661 "\t triggers: a command to perform when function is hit\n"
5662 "\t Format: <function>:<trigger>[:count]\n"
5663 "\t trigger: traceon, traceoff\n"
5664 "\t\t enable_event:<system>:<event>\n"
5665 "\t\t disable_event:<system>:<event>\n"
5666 #ifdef CONFIG_STACKTRACE
5669 #ifdef CONFIG_TRACER_SNAPSHOT
5674 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
5675 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
5676 "\t The first one will disable tracing every time do_fault is hit\n"
5677 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
5678 "\t The first time do trap is hit and it disables tracing, the\n"
5679 "\t counter will decrement to 2. If tracing is already disabled,\n"
5680 "\t the counter will not decrement. It only decrements when the\n"
5681 "\t trigger did work\n"
5682 "\t To remove trigger without count:\n"
5683 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
5684 "\t To remove trigger with a count:\n"
5685 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
5686 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
5687 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
5688 "\t modules: Can select a group via module command :mod:\n"
5689 "\t Does not accept triggers\n"
5690 #endif /* CONFIG_DYNAMIC_FTRACE */
5691 #ifdef CONFIG_FUNCTION_TRACER
5692 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
5694 " set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n"
5697 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5698 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
5699 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
5700 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
5702 #ifdef CONFIG_TRACER_SNAPSHOT
5703 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
5704 "\t\t\t snapshot buffer. Read the contents for more\n"
5705 "\t\t\t information\n"
5707 #ifdef CONFIG_STACK_TRACER
5708 " stack_trace\t\t- Shows the max stack trace when active\n"
5709 " stack_max_size\t- Shows current max stack size that was traced\n"
5710 "\t\t\t Write into this file to reset the max size (trigger a\n"
5711 "\t\t\t new trace)\n"
5712 #ifdef CONFIG_DYNAMIC_FTRACE
5713 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
5716 #endif /* CONFIG_STACK_TRACER */
5717 #ifdef CONFIG_DYNAMIC_EVENTS
5718 " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
5719 "\t\t\t Write into this file to define/undefine new trace events.\n"
5721 #ifdef CONFIG_KPROBE_EVENTS
5722 " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
5723 "\t\t\t Write into this file to define/undefine new trace events.\n"
5725 #ifdef CONFIG_UPROBE_EVENTS
5726 " uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
5727 "\t\t\t Write into this file to define/undefine new trace events.\n"
5729 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) || \
5730 defined(CONFIG_FPROBE_EVENTS)
5731 "\t accepts: event-definitions (one definition per line)\n"
5732 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
5733 "\t Format: p[:[<group>/][<event>]] <place> [<args>]\n"
5734 "\t r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
5736 #ifdef CONFIG_FPROBE_EVENTS
5737 "\t f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
5738 "\t t[:[<group>/][<event>]] <tracepoint> [<args>]\n"
5740 #ifdef CONFIG_HIST_TRIGGERS
5741 "\t s:[synthetic/]<event> <field> [<field>]\n"
5743 "\t e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>] [if <filter>]\n"
5744 "\t -:[<group>/][<event>]\n"
5745 #ifdef CONFIG_KPROBE_EVENTS
5746 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
5747 "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"
5749 #ifdef CONFIG_UPROBE_EVENTS
5750 " place (uprobe): <path>:<offset>[%return][(ref_ctr_offset)]\n"
5752 "\t args: <name>=fetcharg[:type]\n"
5753 "\t fetcharg: (%<register>|$<efield>), @<address>, @<symbol>[+|-<offset>],\n"
5754 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
5755 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
5756 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5757 "\t <argname>[->field[->field|.field...]],\n"
5759 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5762 "\t $stack<index>, $stack, $retval, $comm,\n"
5764 "\t +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
5765 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, char, string, symbol,\n"
5766 "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
5767 "\t symstr, <type>\\[<array-size>\\]\n"
5768 #ifdef CONFIG_HIST_TRIGGERS
5769 "\t field: <stype> <name>;\n"
5770 "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
5771 "\t [unsigned] char/int/long\n"
5773 "\t efield: For event probes ('e' types), the field is on of the fields\n"
5774 "\t of the <attached-group>/<attached-event>.\n"
5776 " events/\t\t- Directory containing all trace event subsystems:\n"
5777 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
5778 " events/<system>/\t- Directory containing all trace events for <system>:\n"
5779 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
5781 " filter\t\t- If set, only events passing filter are traced\n"
5782 " events/<system>/<event>/\t- Directory containing control files for\n"
5784 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
5785 " filter\t\t- If set, only events passing filter are traced\n"
5786 " trigger\t\t- If set, a command to perform when event is hit\n"
5787 "\t Format: <trigger>[:count][if <filter>]\n"
5788 "\t trigger: traceon, traceoff\n"
5789 "\t enable_event:<system>:<event>\n"
5790 "\t disable_event:<system>:<event>\n"
5791 #ifdef CONFIG_HIST_TRIGGERS
5792 "\t enable_hist:<system>:<event>\n"
5793 "\t disable_hist:<system>:<event>\n"
5795 #ifdef CONFIG_STACKTRACE
5798 #ifdef CONFIG_TRACER_SNAPSHOT
5801 #ifdef CONFIG_HIST_TRIGGERS
5802 "\t\t hist (see below)\n"
5804 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
5805 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
5806 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
5807 "\t events/block/block_unplug/trigger\n"
5808 "\t The first disables tracing every time block_unplug is hit.\n"
5809 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
5810 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
5811 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
5812 "\t Like function triggers, the counter is only decremented if it\n"
5813 "\t enabled or disabled tracing.\n"
5814 "\t To remove a trigger without a count:\n"
5815 "\t echo '!<trigger> > <system>/<event>/trigger\n"
5816 "\t To remove a trigger with a count:\n"
5817 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
5818 "\t Filters can be ignored when removing a trigger.\n"
5819 #ifdef CONFIG_HIST_TRIGGERS
5820 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
5821 "\t Format: hist:keys=<field1[,field2,...]>\n"
5822 "\t [:<var1>=<field|var_ref|numeric_literal>[,<var2>=...]]\n"
5823 "\t [:values=<field1[,field2,...]>]\n"
5824 "\t [:sort=<field1[,field2,...]>]\n"
5825 "\t [:size=#entries]\n"
5826 "\t [:pause][:continue][:clear]\n"
5827 "\t [:name=histname1]\n"
5828 "\t [:nohitcount]\n"
5829 "\t [:<handler>.<action>]\n"
5830 "\t [if <filter>]\n\n"
5831 "\t Note, special fields can be used as well:\n"
5832 "\t common_timestamp - to record current timestamp\n"
5833 "\t common_cpu - to record the CPU the event happened on\n"
5835 "\t A hist trigger variable can be:\n"
5836 "\t - a reference to a field e.g. x=current_timestamp,\n"
5837 "\t - a reference to another variable e.g. y=$x,\n"
5838 "\t - a numeric literal: e.g. ms_per_sec=1000,\n"
5839 "\t - an arithmetic expression: e.g. time_secs=current_timestamp/1000\n"
5841 "\t hist trigger arithmetic expressions support addition(+), subtraction(-),\n"
5842 "\t multiplication(*) and division(/) operators. An operand can be either a\n"
5843 "\t variable reference, field or numeric literal.\n"
5845 "\t When a matching event is hit, an entry is added to a hash\n"
5846 "\t table using the key(s) and value(s) named, and the value of a\n"
5847 "\t sum called 'hitcount' is incremented. Keys and values\n"
5848 "\t correspond to fields in the event's format description. Keys\n"
5849 "\t can be any field, or the special string 'common_stacktrace'.\n"
5850 "\t Compound keys consisting of up to two fields can be specified\n"
5851 "\t by the 'keys' keyword. Values must correspond to numeric\n"
5852 "\t fields. Sort keys consisting of up to two fields can be\n"
5853 "\t specified using the 'sort' keyword. The sort direction can\n"
5854 "\t be modified by appending '.descending' or '.ascending' to a\n"
5855 "\t sort field. The 'size' parameter can be used to specify more\n"
5856 "\t or fewer than the default 2048 entries for the hashtable size.\n"
5857 "\t If a hist trigger is given a name using the 'name' parameter,\n"
5858 "\t its histogram data will be shared with other triggers of the\n"
5859 "\t same name, and trigger hits will update this common data.\n\n"
5860 "\t Reading the 'hist' file for the event will dump the hash\n"
5861 "\t table in its entirety to stdout. If there are multiple hist\n"
5862 "\t triggers attached to an event, there will be a table for each\n"
5863 "\t trigger in the output. The table displayed for a named\n"
5864 "\t trigger will be the same as any other instance having the\n"
5865 "\t same name. The default format used to display a given field\n"
5866 "\t can be modified by appending any of the following modifiers\n"
5867 "\t to the field name, as applicable:\n\n"
5868 "\t .hex display a number as a hex value\n"
5869 "\t .sym display an address as a symbol\n"
5870 "\t .sym-offset display an address as a symbol and offset\n"
5871 "\t .execname display a common_pid as a program name\n"
5872 "\t .syscall display a syscall id as a syscall name\n"
5873 "\t .log2 display log2 value rather than raw number\n"
5874 "\t .buckets=size display values in groups of size rather than raw number\n"
5875 "\t .usecs display a common_timestamp in microseconds\n"
5876 "\t .percent display a number of percentage value\n"
5877 "\t .graph display a bar-graph of a value\n\n"
5878 "\t The 'pause' parameter can be used to pause an existing hist\n"
5879 "\t trigger or to start a hist trigger but not log any events\n"
5880 "\t until told to do so. 'continue' can be used to start or\n"
5881 "\t restart a paused hist trigger.\n\n"
5882 "\t The 'clear' parameter will clear the contents of a running\n"
5883 "\t hist trigger and leave its current paused/active state\n"
5885 "\t The 'nohitcount' (or NOHC) parameter will suppress display of\n"
5886 "\t raw hitcount in the histogram.\n\n"
5887 "\t The enable_hist and disable_hist triggers can be used to\n"
5888 "\t have one event conditionally start and stop another event's\n"
5889 "\t already-attached hist trigger. The syntax is analogous to\n"
5890 "\t the enable_event and disable_event triggers.\n\n"
5891 "\t Hist trigger handlers and actions are executed whenever a\n"
5892 "\t a histogram entry is added or updated. They take the form:\n\n"
5893 "\t <handler>.<action>\n\n"
5894 "\t The available handlers are:\n\n"
5895 "\t onmatch(matching.event) - invoke on addition or update\n"
5896 "\t onmax(var) - invoke if var exceeds current max\n"
5897 "\t onchange(var) - invoke action if var changes\n\n"
5898 "\t The available actions are:\n\n"
5899 "\t trace(<synthetic_event>,param list) - generate synthetic event\n"
5900 "\t save(field,...) - save current event fields\n"
5901 #ifdef CONFIG_TRACER_SNAPSHOT
5902 "\t snapshot() - snapshot the trace buffer\n\n"
5904 #ifdef CONFIG_SYNTH_EVENTS
5905 " events/synthetic_events\t- Create/append/remove/show synthetic events\n"
5906 "\t Write into this file to define/undefine new synthetic events.\n"
5907 "\t example: echo 'myevent u64 lat; char name[]; long[] stack' >> synthetic_events\n"
5913 tracing_readme_read(struct file *filp, char __user *ubuf,
5914 size_t cnt, loff_t *ppos)
5916 return simple_read_from_buffer(ubuf, cnt, ppos,
5917 readme_msg, strlen(readme_msg));
5920 static const struct file_operations tracing_readme_fops = {
5921 .open = tracing_open_generic,
5922 .read = tracing_readme_read,
5923 .llseek = generic_file_llseek,
5926 static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
5930 return trace_find_tgid_ptr(pid);
5933 static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
5937 return trace_find_tgid_ptr(pid);
5940 static void saved_tgids_stop(struct seq_file *m, void *v)
5944 static int saved_tgids_show(struct seq_file *m, void *v)
5946 int *entry = (int *)v;
5947 int pid = entry - tgid_map;
5953 seq_printf(m, "%d %d\n", pid, tgid);
5957 static const struct seq_operations tracing_saved_tgids_seq_ops = {
5958 .start = saved_tgids_start,
5959 .stop = saved_tgids_stop,
5960 .next = saved_tgids_next,
5961 .show = saved_tgids_show,
5964 static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
5968 ret = tracing_check_open_get_tr(NULL);
5972 return seq_open(filp, &tracing_saved_tgids_seq_ops);
5976 static const struct file_operations tracing_saved_tgids_fops = {
5977 .open = tracing_saved_tgids_open,
5979 .llseek = seq_lseek,
5980 .release = seq_release,
5983 static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
5985 unsigned int *ptr = v;
5987 if (*pos || m->count)
5992 for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
5994 if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
6003 static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
6009 arch_spin_lock(&trace_cmdline_lock);
6011 v = &savedcmd->map_cmdline_to_pid[0];
6013 v = saved_cmdlines_next(m, v, &l);
6021 static void saved_cmdlines_stop(struct seq_file *m, void *v)
6023 arch_spin_unlock(&trace_cmdline_lock);
6027 static int saved_cmdlines_show(struct seq_file *m, void *v)
6029 char buf[TASK_COMM_LEN];
6030 unsigned int *pid = v;
6032 __trace_find_cmdline(*pid, buf);
6033 seq_printf(m, "%d %s\n", *pid, buf);
6037 static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
6038 .start = saved_cmdlines_start,
6039 .next = saved_cmdlines_next,
6040 .stop = saved_cmdlines_stop,
6041 .show = saved_cmdlines_show,
6044 static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
6048 ret = tracing_check_open_get_tr(NULL);
6052 return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
6055 static const struct file_operations tracing_saved_cmdlines_fops = {
6056 .open = tracing_saved_cmdlines_open,
6058 .llseek = seq_lseek,
6059 .release = seq_release,
6063 tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
6064 size_t cnt, loff_t *ppos)
6070 arch_spin_lock(&trace_cmdline_lock);
6071 r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
6072 arch_spin_unlock(&trace_cmdline_lock);
6075 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6078 static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
6080 kfree(s->saved_cmdlines);
6081 kfree(s->map_cmdline_to_pid);
6085 static int tracing_resize_saved_cmdlines(unsigned int val)
6087 struct saved_cmdlines_buffer *s, *savedcmd_temp;
6089 s = kmalloc(sizeof(*s), GFP_KERNEL);
6093 if (allocate_cmdlines_buffer(val, s) < 0) {
6099 arch_spin_lock(&trace_cmdline_lock);
6100 savedcmd_temp = savedcmd;
6102 arch_spin_unlock(&trace_cmdline_lock);
6104 free_saved_cmdlines_buffer(savedcmd_temp);
6110 tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
6111 size_t cnt, loff_t *ppos)
6116 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6120 /* must have at least 1 entry or less than PID_MAX_DEFAULT */
6121 if (!val || val > PID_MAX_DEFAULT)
6124 ret = tracing_resize_saved_cmdlines((unsigned int)val);
6133 static const struct file_operations tracing_saved_cmdlines_size_fops = {
6134 .open = tracing_open_generic,
6135 .read = tracing_saved_cmdlines_size_read,
6136 .write = tracing_saved_cmdlines_size_write,
6139 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
6140 static union trace_eval_map_item *
6141 update_eval_map(union trace_eval_map_item *ptr)
6143 if (!ptr->map.eval_string) {
6144 if (ptr->tail.next) {
6145 ptr = ptr->tail.next;
6146 /* Set ptr to the next real item (skip head) */
6154 static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
6156 union trace_eval_map_item *ptr = v;
6159 * Paranoid! If ptr points to end, we don't want to increment past it.
6160 * This really should never happen.
6163 ptr = update_eval_map(ptr);
6164 if (WARN_ON_ONCE(!ptr))
6168 ptr = update_eval_map(ptr);
6173 static void *eval_map_start(struct seq_file *m, loff_t *pos)
6175 union trace_eval_map_item *v;
6178 mutex_lock(&trace_eval_mutex);
6180 v = trace_eval_maps;
6184 while (v && l < *pos) {
6185 v = eval_map_next(m, v, &l);
6191 static void eval_map_stop(struct seq_file *m, void *v)
6193 mutex_unlock(&trace_eval_mutex);
6196 static int eval_map_show(struct seq_file *m, void *v)
6198 union trace_eval_map_item *ptr = v;
6200 seq_printf(m, "%s %ld (%s)\n",
6201 ptr->map.eval_string, ptr->map.eval_value,
6207 static const struct seq_operations tracing_eval_map_seq_ops = {
6208 .start = eval_map_start,
6209 .next = eval_map_next,
6210 .stop = eval_map_stop,
6211 .show = eval_map_show,
6214 static int tracing_eval_map_open(struct inode *inode, struct file *filp)
6218 ret = tracing_check_open_get_tr(NULL);
6222 return seq_open(filp, &tracing_eval_map_seq_ops);
6225 static const struct file_operations tracing_eval_map_fops = {
6226 .open = tracing_eval_map_open,
6228 .llseek = seq_lseek,
6229 .release = seq_release,
6232 static inline union trace_eval_map_item *
6233 trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
6235 /* Return tail of array given the head */
6236 return ptr + ptr->head.length + 1;
6240 trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
6243 struct trace_eval_map **stop;
6244 struct trace_eval_map **map;
6245 union trace_eval_map_item *map_array;
6246 union trace_eval_map_item *ptr;
6251 * The trace_eval_maps contains the map plus a head and tail item,
6252 * where the head holds the module and length of array, and the
6253 * tail holds a pointer to the next list.
6255 map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
6257 pr_warn("Unable to allocate trace eval mapping\n");
6261 mutex_lock(&trace_eval_mutex);
6263 if (!trace_eval_maps)
6264 trace_eval_maps = map_array;
6266 ptr = trace_eval_maps;
6268 ptr = trace_eval_jmp_to_tail(ptr);
6269 if (!ptr->tail.next)
6271 ptr = ptr->tail.next;
6274 ptr->tail.next = map_array;
6276 map_array->head.mod = mod;
6277 map_array->head.length = len;
6280 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
6281 map_array->map = **map;
6284 memset(map_array, 0, sizeof(*map_array));
6286 mutex_unlock(&trace_eval_mutex);
6289 static void trace_create_eval_file(struct dentry *d_tracer)
6291 trace_create_file("eval_map", TRACE_MODE_READ, d_tracer,
6292 NULL, &tracing_eval_map_fops);
6295 #else /* CONFIG_TRACE_EVAL_MAP_FILE */
6296 static inline void trace_create_eval_file(struct dentry *d_tracer) { }
6297 static inline void trace_insert_eval_map_file(struct module *mod,
6298 struct trace_eval_map **start, int len) { }
6299 #endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
6301 static void trace_insert_eval_map(struct module *mod,
6302 struct trace_eval_map **start, int len)
6304 struct trace_eval_map **map;
6311 trace_event_eval_update(map, len);
6313 trace_insert_eval_map_file(mod, start, len);
6317 tracing_set_trace_read(struct file *filp, char __user *ubuf,
6318 size_t cnt, loff_t *ppos)
6320 struct trace_array *tr = filp->private_data;
6321 char buf[MAX_TRACER_SIZE+2];
6324 mutex_lock(&trace_types_lock);
6325 r = sprintf(buf, "%s\n", tr->current_trace->name);
6326 mutex_unlock(&trace_types_lock);
6328 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6331 int tracer_init(struct tracer *t, struct trace_array *tr)
6333 tracing_reset_online_cpus(&tr->array_buffer);
6337 static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
6341 for_each_tracing_cpu(cpu)
6342 per_cpu_ptr(buf->data, cpu)->entries = val;
6345 static void update_buffer_entries(struct array_buffer *buf, int cpu)
6347 if (cpu == RING_BUFFER_ALL_CPUS) {
6348 set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0));
6350 per_cpu_ptr(buf->data, cpu)->entries = ring_buffer_size(buf->buffer, cpu);
6354 #ifdef CONFIG_TRACER_MAX_TRACE
6355 /* resize @tr's buffer to the size of @size_tr's entries */
6356 static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
6357 struct array_buffer *size_buf, int cpu_id)
6361 if (cpu_id == RING_BUFFER_ALL_CPUS) {
6362 for_each_tracing_cpu(cpu) {
6363 ret = ring_buffer_resize(trace_buf->buffer,
6364 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
6367 per_cpu_ptr(trace_buf->data, cpu)->entries =
6368 per_cpu_ptr(size_buf->data, cpu)->entries;
6371 ret = ring_buffer_resize(trace_buf->buffer,
6372 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
6374 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
6375 per_cpu_ptr(size_buf->data, cpu_id)->entries;
6380 #endif /* CONFIG_TRACER_MAX_TRACE */
6382 static int __tracing_resize_ring_buffer(struct trace_array *tr,
6383 unsigned long size, int cpu)
6388 * If kernel or user changes the size of the ring buffer
6389 * we use the size that was given, and we can forget about
6390 * expanding it later.
6392 ring_buffer_expanded = true;
6394 /* May be called before buffers are initialized */
6395 if (!tr->array_buffer.buffer)
6398 ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu);
6402 #ifdef CONFIG_TRACER_MAX_TRACE
6403 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
6404 !tr->current_trace->use_max_tr)
6407 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
6409 int r = resize_buffer_duplicate_size(&tr->array_buffer,
6410 &tr->array_buffer, cpu);
6413 * AARGH! We are left with different
6414 * size max buffer!!!!
6415 * The max buffer is our "snapshot" buffer.
6416 * When a tracer needs a snapshot (one of the
6417 * latency tracers), it swaps the max buffer
6418 * with the saved snap shot. We succeeded to
6419 * update the size of the main buffer, but failed to
6420 * update the size of the max buffer. But when we tried
6421 * to reset the main buffer to the original size, we
6422 * failed there too. This is very unlikely to
6423 * happen, but if it does, warn and kill all
6427 tracing_disabled = 1;
6432 update_buffer_entries(&tr->max_buffer, cpu);
6435 #endif /* CONFIG_TRACER_MAX_TRACE */
6437 update_buffer_entries(&tr->array_buffer, cpu);
6442 ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
6443 unsigned long size, int cpu_id)
6447 mutex_lock(&trace_types_lock);
6449 if (cpu_id != RING_BUFFER_ALL_CPUS) {
6450 /* make sure, this cpu is enabled in the mask */
6451 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
6457 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
6462 mutex_unlock(&trace_types_lock);
6469 * tracing_update_buffers - used by tracing facility to expand ring buffers
6471 * To save on memory when the tracing is never used on a system with it
6472 * configured in. The ring buffers are set to a minimum size. But once
6473 * a user starts to use the tracing facility, then they need to grow
6474 * to their default size.
6476 * This function is to be called when a tracer is about to be used.
6478 int tracing_update_buffers(void)
6482 mutex_lock(&trace_types_lock);
6483 if (!ring_buffer_expanded)
6484 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
6485 RING_BUFFER_ALL_CPUS);
6486 mutex_unlock(&trace_types_lock);
6491 struct trace_option_dentry;
6494 create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
6497 * Used to clear out the tracer before deletion of an instance.
6498 * Must have trace_types_lock held.
6500 static void tracing_set_nop(struct trace_array *tr)
6502 if (tr->current_trace == &nop_trace)
6505 tr->current_trace->enabled--;
6507 if (tr->current_trace->reset)
6508 tr->current_trace->reset(tr);
6510 tr->current_trace = &nop_trace;
6513 static bool tracer_options_updated;
6515 static void add_tracer_options(struct trace_array *tr, struct tracer *t)
6517 /* Only enable if the directory has been created already. */
6521 /* Only create trace option files after update_tracer_options finish */
6522 if (!tracer_options_updated)
6525 create_trace_option_files(tr, t);
6528 int tracing_set_tracer(struct trace_array *tr, const char *buf)
6531 #ifdef CONFIG_TRACER_MAX_TRACE
6536 mutex_lock(&trace_types_lock);
6538 if (!ring_buffer_expanded) {
6539 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6540 RING_BUFFER_ALL_CPUS);
6546 for (t = trace_types; t; t = t->next) {
6547 if (strcmp(t->name, buf) == 0)
6554 if (t == tr->current_trace)
6557 #ifdef CONFIG_TRACER_SNAPSHOT
6558 if (t->use_max_tr) {
6559 local_irq_disable();
6560 arch_spin_lock(&tr->max_lock);
6561 if (tr->cond_snapshot)
6563 arch_spin_unlock(&tr->max_lock);
6569 /* Some tracers won't work on kernel command line */
6570 if (system_state < SYSTEM_RUNNING && t->noboot) {
6571 pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
6576 /* Some tracers are only allowed for the top level buffer */
6577 if (!trace_ok_for_array(t, tr)) {
6582 /* If trace pipe files are being read, we can't change the tracer */
6583 if (tr->trace_ref) {
6588 trace_branch_disable();
6590 tr->current_trace->enabled--;
6592 if (tr->current_trace->reset)
6593 tr->current_trace->reset(tr);
6595 #ifdef CONFIG_TRACER_MAX_TRACE
6596 had_max_tr = tr->current_trace->use_max_tr;
6598 /* Current trace needs to be nop_trace before synchronize_rcu */
6599 tr->current_trace = &nop_trace;
6601 if (had_max_tr && !t->use_max_tr) {
6603 * We need to make sure that the update_max_tr sees that
6604 * current_trace changed to nop_trace to keep it from
6605 * swapping the buffers after we resize it.
6606 * The update_max_tr is called from interrupts disabled
6607 * so a synchronized_sched() is sufficient.
6613 if (t->use_max_tr && !tr->allocated_snapshot) {
6614 ret = tracing_alloc_snapshot_instance(tr);
6619 tr->current_trace = &nop_trace;
6623 ret = tracer_init(t, tr);
6628 tr->current_trace = t;
6629 tr->current_trace->enabled++;
6630 trace_branch_enable(tr);
6632 mutex_unlock(&trace_types_lock);
6638 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
6639 size_t cnt, loff_t *ppos)
6641 struct trace_array *tr = filp->private_data;
6642 char buf[MAX_TRACER_SIZE+1];
6649 if (cnt > MAX_TRACER_SIZE)
6650 cnt = MAX_TRACER_SIZE;
6652 if (copy_from_user(buf, ubuf, cnt))
6659 err = tracing_set_tracer(tr, name);
6669 tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
6670 size_t cnt, loff_t *ppos)
6675 r = snprintf(buf, sizeof(buf), "%ld\n",
6676 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
6677 if (r > sizeof(buf))
6679 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6683 tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
6684 size_t cnt, loff_t *ppos)
6689 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6699 tracing_thresh_read(struct file *filp, char __user *ubuf,
6700 size_t cnt, loff_t *ppos)
6702 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
6706 tracing_thresh_write(struct file *filp, const char __user *ubuf,
6707 size_t cnt, loff_t *ppos)
6709 struct trace_array *tr = filp->private_data;
6712 mutex_lock(&trace_types_lock);
6713 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
6717 if (tr->current_trace->update_thresh) {
6718 ret = tr->current_trace->update_thresh(tr);
6725 mutex_unlock(&trace_types_lock);
6730 #ifdef CONFIG_TRACER_MAX_TRACE
6733 tracing_max_lat_read(struct file *filp, char __user *ubuf,
6734 size_t cnt, loff_t *ppos)
6736 struct trace_array *tr = filp->private_data;
6738 return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos);
6742 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
6743 size_t cnt, loff_t *ppos)
6745 struct trace_array *tr = filp->private_data;
6747 return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos);
6752 static int open_pipe_on_cpu(struct trace_array *tr, int cpu)
6754 if (cpu == RING_BUFFER_ALL_CPUS) {
6755 if (cpumask_empty(tr->pipe_cpumask)) {
6756 cpumask_setall(tr->pipe_cpumask);
6759 } else if (!cpumask_test_cpu(cpu, tr->pipe_cpumask)) {
6760 cpumask_set_cpu(cpu, tr->pipe_cpumask);
6766 static void close_pipe_on_cpu(struct trace_array *tr, int cpu)
6768 if (cpu == RING_BUFFER_ALL_CPUS) {
6769 WARN_ON(!cpumask_full(tr->pipe_cpumask));
6770 cpumask_clear(tr->pipe_cpumask);
6772 WARN_ON(!cpumask_test_cpu(cpu, tr->pipe_cpumask));
6773 cpumask_clear_cpu(cpu, tr->pipe_cpumask);
6777 static int tracing_open_pipe(struct inode *inode, struct file *filp)
6779 struct trace_array *tr = inode->i_private;
6780 struct trace_iterator *iter;
6784 ret = tracing_check_open_get_tr(tr);
6788 mutex_lock(&trace_types_lock);
6789 cpu = tracing_get_cpu(inode);
6790 ret = open_pipe_on_cpu(tr, cpu);
6792 goto fail_pipe_on_cpu;
6794 /* create a buffer to store the information to pass to userspace */
6795 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6798 goto fail_alloc_iter;
6801 trace_seq_init(&iter->seq);
6802 iter->trace = tr->current_trace;
6804 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
6809 /* trace pipe does not show start of buffer */
6810 cpumask_setall(iter->started);
6812 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
6813 iter->iter_flags |= TRACE_FILE_LAT_FMT;
6815 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6816 if (trace_clocks[tr->clock_id].in_ns)
6817 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
6820 iter->array_buffer = &tr->array_buffer;
6821 iter->cpu_file = cpu;
6822 mutex_init(&iter->mutex);
6823 filp->private_data = iter;
6825 if (iter->trace->pipe_open)
6826 iter->trace->pipe_open(iter);
6828 nonseekable_open(inode, filp);
6832 mutex_unlock(&trace_types_lock);
6838 close_pipe_on_cpu(tr, cpu);
6840 __trace_array_put(tr);
6841 mutex_unlock(&trace_types_lock);
6845 static int tracing_release_pipe(struct inode *inode, struct file *file)
6847 struct trace_iterator *iter = file->private_data;
6848 struct trace_array *tr = inode->i_private;
6850 mutex_lock(&trace_types_lock);
6854 if (iter->trace->pipe_close)
6855 iter->trace->pipe_close(iter);
6856 close_pipe_on_cpu(tr, iter->cpu_file);
6857 mutex_unlock(&trace_types_lock);
6859 free_trace_iter_content(iter);
6862 trace_array_put(tr);
6868 trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
6870 struct trace_array *tr = iter->tr;
6872 /* Iterators are static, they should be filled or empty */
6873 if (trace_buffer_iter(iter, iter->cpu_file))
6874 return EPOLLIN | EPOLLRDNORM;
6876 if (tr->trace_flags & TRACE_ITER_BLOCK)
6878 * Always select as readable when in blocking mode
6880 return EPOLLIN | EPOLLRDNORM;
6882 return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file,
6883 filp, poll_table, iter->tr->buffer_percent);
6887 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
6889 struct trace_iterator *iter = filp->private_data;
6891 return trace_poll(iter, filp, poll_table);
6894 /* Must be called with iter->mutex held. */
6895 static int tracing_wait_pipe(struct file *filp)
6897 struct trace_iterator *iter = filp->private_data;
6900 while (trace_empty(iter)) {
6902 if ((filp->f_flags & O_NONBLOCK)) {
6907 * We block until we read something and tracing is disabled.
6908 * We still block if tracing is disabled, but we have never
6909 * read anything. This allows a user to cat this file, and
6910 * then enable tracing. But after we have read something,
6911 * we give an EOF when tracing is again disabled.
6913 * iter->pos will be 0 if we haven't read anything.
6915 if (!tracer_tracing_is_on(iter->tr) && iter->pos)
6918 mutex_unlock(&iter->mutex);
6920 ret = wait_on_pipe(iter, 0);
6922 mutex_lock(&iter->mutex);
6935 tracing_read_pipe(struct file *filp, char __user *ubuf,
6936 size_t cnt, loff_t *ppos)
6938 struct trace_iterator *iter = filp->private_data;
6942 * Avoid more than one consumer on a single file descriptor
6943 * This is just a matter of traces coherency, the ring buffer itself
6946 mutex_lock(&iter->mutex);
6948 /* return any leftover data */
6949 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6953 trace_seq_init(&iter->seq);
6955 if (iter->trace->read) {
6956 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
6962 sret = tracing_wait_pipe(filp);
6966 /* stop when tracing is finished */
6967 if (trace_empty(iter)) {
6972 if (cnt >= PAGE_SIZE)
6973 cnt = PAGE_SIZE - 1;
6975 /* reset all but tr, trace, and overruns */
6976 trace_iterator_reset(iter);
6977 cpumask_clear(iter->started);
6978 trace_seq_init(&iter->seq);
6980 trace_event_read_lock();
6981 trace_access_lock(iter->cpu_file);
6982 while (trace_find_next_entry_inc(iter) != NULL) {
6983 enum print_line_t ret;
6984 int save_len = iter->seq.seq.len;
6986 ret = print_trace_line(iter);
6987 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6989 * If one print_trace_line() fills entire trace_seq in one shot,
6990 * trace_seq_to_user() will returns -EBUSY because save_len == 0,
6991 * In this case, we need to consume it, otherwise, loop will peek
6992 * this event next time, resulting in an infinite loop.
6994 if (save_len == 0) {
6996 trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
6997 trace_consume(iter);
7001 /* In other cases, don't print partial lines */
7002 iter->seq.seq.len = save_len;
7005 if (ret != TRACE_TYPE_NO_CONSUME)
7006 trace_consume(iter);
7008 if (trace_seq_used(&iter->seq) >= cnt)
7012 * Setting the full flag means we reached the trace_seq buffer
7013 * size and we should leave by partial output condition above.
7014 * One of the trace_seq_* functions is not used properly.
7016 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
7019 trace_access_unlock(iter->cpu_file);
7020 trace_event_read_unlock();
7022 /* Now copy what we have to the user */
7023 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
7024 if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
7025 trace_seq_init(&iter->seq);
7028 * If there was nothing to send to user, in spite of consuming trace
7029 * entries, go back to wait for more entries.
7035 mutex_unlock(&iter->mutex);
7040 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
7043 __free_page(spd->pages[idx]);
7047 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
7053 /* Seq buffer is page-sized, exactly what we need. */
7055 save_len = iter->seq.seq.len;
7056 ret = print_trace_line(iter);
7058 if (trace_seq_has_overflowed(&iter->seq)) {
7059 iter->seq.seq.len = save_len;
7064 * This should not be hit, because it should only
7065 * be set if the iter->seq overflowed. But check it
7066 * anyway to be safe.
7068 if (ret == TRACE_TYPE_PARTIAL_LINE) {
7069 iter->seq.seq.len = save_len;
7073 count = trace_seq_used(&iter->seq) - save_len;
7076 iter->seq.seq.len = save_len;
7080 if (ret != TRACE_TYPE_NO_CONSUME)
7081 trace_consume(iter);
7083 if (!trace_find_next_entry_inc(iter)) {
7093 static ssize_t tracing_splice_read_pipe(struct file *filp,
7095 struct pipe_inode_info *pipe,
7099 struct page *pages_def[PIPE_DEF_BUFFERS];
7100 struct partial_page partial_def[PIPE_DEF_BUFFERS];
7101 struct trace_iterator *iter = filp->private_data;
7102 struct splice_pipe_desc spd = {
7104 .partial = partial_def,
7105 .nr_pages = 0, /* This gets updated below. */
7106 .nr_pages_max = PIPE_DEF_BUFFERS,
7107 .ops = &default_pipe_buf_ops,
7108 .spd_release = tracing_spd_release_pipe,
7114 if (splice_grow_spd(pipe, &spd))
7117 mutex_lock(&iter->mutex);
7119 if (iter->trace->splice_read) {
7120 ret = iter->trace->splice_read(iter, filp,
7121 ppos, pipe, len, flags);
7126 ret = tracing_wait_pipe(filp);
7130 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
7135 trace_event_read_lock();
7136 trace_access_lock(iter->cpu_file);
7138 /* Fill as many pages as possible. */
7139 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
7140 spd.pages[i] = alloc_page(GFP_KERNEL);
7144 rem = tracing_fill_pipe_page(rem, iter);
7146 /* Copy the data into the page, so we can start over. */
7147 ret = trace_seq_to_buffer(&iter->seq,
7148 page_address(spd.pages[i]),
7149 trace_seq_used(&iter->seq));
7151 __free_page(spd.pages[i]);
7154 spd.partial[i].offset = 0;
7155 spd.partial[i].len = trace_seq_used(&iter->seq);
7157 trace_seq_init(&iter->seq);
7160 trace_access_unlock(iter->cpu_file);
7161 trace_event_read_unlock();
7162 mutex_unlock(&iter->mutex);
7167 ret = splice_to_pipe(pipe, &spd);
7171 splice_shrink_spd(&spd);
7175 mutex_unlock(&iter->mutex);
7180 tracing_entries_read(struct file *filp, char __user *ubuf,
7181 size_t cnt, loff_t *ppos)
7183 struct inode *inode = file_inode(filp);
7184 struct trace_array *tr = inode->i_private;
7185 int cpu = tracing_get_cpu(inode);
7190 mutex_lock(&trace_types_lock);
7192 if (cpu == RING_BUFFER_ALL_CPUS) {
7193 int cpu, buf_size_same;
7198 /* check if all cpu sizes are same */
7199 for_each_tracing_cpu(cpu) {
7200 /* fill in the size from first enabled cpu */
7202 size = per_cpu_ptr(tr->array_buffer.data, cpu)->entries;
7203 if (size != per_cpu_ptr(tr->array_buffer.data, cpu)->entries) {
7209 if (buf_size_same) {
7210 if (!ring_buffer_expanded)
7211 r = sprintf(buf, "%lu (expanded: %lu)\n",
7213 trace_buf_size >> 10);
7215 r = sprintf(buf, "%lu\n", size >> 10);
7217 r = sprintf(buf, "X\n");
7219 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10);
7221 mutex_unlock(&trace_types_lock);
7223 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7228 tracing_entries_write(struct file *filp, const char __user *ubuf,
7229 size_t cnt, loff_t *ppos)
7231 struct inode *inode = file_inode(filp);
7232 struct trace_array *tr = inode->i_private;
7236 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7240 /* must have at least 1 entry */
7244 /* value is in KB */
7246 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
7256 tracing_total_entries_read(struct file *filp, char __user *ubuf,
7257 size_t cnt, loff_t *ppos)
7259 struct trace_array *tr = filp->private_data;
7262 unsigned long size = 0, expanded_size = 0;
7264 mutex_lock(&trace_types_lock);
7265 for_each_tracing_cpu(cpu) {
7266 size += per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10;
7267 if (!ring_buffer_expanded)
7268 expanded_size += trace_buf_size >> 10;
7270 if (ring_buffer_expanded)
7271 r = sprintf(buf, "%lu\n", size);
7273 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
7274 mutex_unlock(&trace_types_lock);
7276 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7280 tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
7281 size_t cnt, loff_t *ppos)
7284 * There is no need to read what the user has written, this function
7285 * is just to make sure that there is no error when "echo" is used
7294 tracing_free_buffer_release(struct inode *inode, struct file *filp)
7296 struct trace_array *tr = inode->i_private;
7298 /* disable tracing ? */
7299 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
7300 tracer_tracing_off(tr);
7301 /* resize the ring buffer to 0 */
7302 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
7304 trace_array_put(tr);
7310 tracing_mark_write(struct file *filp, const char __user *ubuf,
7311 size_t cnt, loff_t *fpos)
7313 struct trace_array *tr = filp->private_data;
7314 struct ring_buffer_event *event;
7315 enum event_trigger_type tt = ETT_NONE;
7316 struct trace_buffer *buffer;
7317 struct print_entry *entry;
7322 /* Used in tracing_mark_raw_write() as well */
7323 #define FAULTED_STR "<faulted>"
7324 #define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
7326 if (tracing_disabled)
7329 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7332 if (cnt > TRACE_BUF_SIZE)
7333 cnt = TRACE_BUF_SIZE;
7335 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
7337 size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
7339 /* If less than "<faulted>", then make sure we can still add that */
7340 if (cnt < FAULTED_SIZE)
7341 size += FAULTED_SIZE - cnt;
7343 buffer = tr->array_buffer.buffer;
7344 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
7346 if (unlikely(!event))
7347 /* Ring buffer disabled, return as if not open for write */
7350 entry = ring_buffer_event_data(event);
7351 entry->ip = _THIS_IP_;
7353 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
7355 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7361 if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
7362 /* do not add \n before testing triggers, but add \0 */
7363 entry->buf[cnt] = '\0';
7364 tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event);
7367 if (entry->buf[cnt - 1] != '\n') {
7368 entry->buf[cnt] = '\n';
7369 entry->buf[cnt + 1] = '\0';
7371 entry->buf[cnt] = '\0';
7373 if (static_branch_unlikely(&trace_marker_exports_enabled))
7374 ftrace_exports(event, TRACE_EXPORT_MARKER);
7375 __buffer_unlock_commit(buffer, event);
7378 event_triggers_post_call(tr->trace_marker_file, tt);
7383 /* Limit it for now to 3K (including tag) */
7384 #define RAW_DATA_MAX_SIZE (1024*3)
7387 tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
7388 size_t cnt, loff_t *fpos)
7390 struct trace_array *tr = filp->private_data;
7391 struct ring_buffer_event *event;
7392 struct trace_buffer *buffer;
7393 struct raw_data_entry *entry;
7398 #define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
7400 if (tracing_disabled)
7403 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7406 /* The marker must at least have a tag id */
7407 if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
7410 if (cnt > TRACE_BUF_SIZE)
7411 cnt = TRACE_BUF_SIZE;
7413 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
7415 size = sizeof(*entry) + cnt;
7416 if (cnt < FAULT_SIZE_ID)
7417 size += FAULT_SIZE_ID - cnt;
7419 buffer = tr->array_buffer.buffer;
7420 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
7423 /* Ring buffer disabled, return as if not open for write */
7426 entry = ring_buffer_event_data(event);
7428 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
7431 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7436 __buffer_unlock_commit(buffer, event);
7441 static int tracing_clock_show(struct seq_file *m, void *v)
7443 struct trace_array *tr = m->private;
7446 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
7448 "%s%s%s%s", i ? " " : "",
7449 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
7450 i == tr->clock_id ? "]" : "");
7456 int tracing_set_clock(struct trace_array *tr, const char *clockstr)
7460 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
7461 if (strcmp(trace_clocks[i].name, clockstr) == 0)
7464 if (i == ARRAY_SIZE(trace_clocks))
7467 mutex_lock(&trace_types_lock);
7471 ring_buffer_set_clock(tr->array_buffer.buffer, trace_clocks[i].func);
7474 * New clock may not be consistent with the previous clock.
7475 * Reset the buffer so that it doesn't have incomparable timestamps.
7477 tracing_reset_online_cpus(&tr->array_buffer);
7479 #ifdef CONFIG_TRACER_MAX_TRACE
7480 if (tr->max_buffer.buffer)
7481 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
7482 tracing_reset_online_cpus(&tr->max_buffer);
7485 mutex_unlock(&trace_types_lock);
7490 static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
7491 size_t cnt, loff_t *fpos)
7493 struct seq_file *m = filp->private_data;
7494 struct trace_array *tr = m->private;
7496 const char *clockstr;
7499 if (cnt >= sizeof(buf))
7502 if (copy_from_user(buf, ubuf, cnt))
7507 clockstr = strstrip(buf);
7509 ret = tracing_set_clock(tr, clockstr);
7518 static int tracing_clock_open(struct inode *inode, struct file *file)
7520 struct trace_array *tr = inode->i_private;
7523 ret = tracing_check_open_get_tr(tr);
7527 ret = single_open(file, tracing_clock_show, inode->i_private);
7529 trace_array_put(tr);
7534 static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
7536 struct trace_array *tr = m->private;
7538 mutex_lock(&trace_types_lock);
7540 if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
7541 seq_puts(m, "delta [absolute]\n");
7543 seq_puts(m, "[delta] absolute\n");
7545 mutex_unlock(&trace_types_lock);
7550 static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
7552 struct trace_array *tr = inode->i_private;
7555 ret = tracing_check_open_get_tr(tr);
7559 ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
7561 trace_array_put(tr);
7566 u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
7568 if (rbe == this_cpu_read(trace_buffered_event))
7569 return ring_buffer_time_stamp(buffer);
7571 return ring_buffer_event_time_stamp(buffer, rbe);
7575 * Set or disable using the per CPU trace_buffer_event when possible.
7577 int tracing_set_filter_buffering(struct trace_array *tr, bool set)
7581 mutex_lock(&trace_types_lock);
7583 if (set && tr->no_filter_buffering_ref++)
7587 if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) {
7592 --tr->no_filter_buffering_ref;
7595 mutex_unlock(&trace_types_lock);
7600 struct ftrace_buffer_info {
7601 struct trace_iterator iter;
7603 unsigned int spare_cpu;
7607 #ifdef CONFIG_TRACER_SNAPSHOT
7608 static int tracing_snapshot_open(struct inode *inode, struct file *file)
7610 struct trace_array *tr = inode->i_private;
7611 struct trace_iterator *iter;
7615 ret = tracing_check_open_get_tr(tr);
7619 if (file->f_mode & FMODE_READ) {
7620 iter = __tracing_open(inode, file, true);
7622 ret = PTR_ERR(iter);
7624 /* Writes still need the seq_file to hold the private data */
7626 m = kzalloc(sizeof(*m), GFP_KERNEL);
7629 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
7637 iter->array_buffer = &tr->max_buffer;
7638 iter->cpu_file = tracing_get_cpu(inode);
7640 file->private_data = m;
7644 trace_array_put(tr);
7649 static void tracing_swap_cpu_buffer(void *tr)
7651 update_max_tr_single((struct trace_array *)tr, current, smp_processor_id());
7655 tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
7658 struct seq_file *m = filp->private_data;
7659 struct trace_iterator *iter = m->private;
7660 struct trace_array *tr = iter->tr;
7664 ret = tracing_update_buffers();
7668 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7672 mutex_lock(&trace_types_lock);
7674 if (tr->current_trace->use_max_tr) {
7679 local_irq_disable();
7680 arch_spin_lock(&tr->max_lock);
7681 if (tr->cond_snapshot)
7683 arch_spin_unlock(&tr->max_lock);
7690 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7694 if (tr->allocated_snapshot)
7698 /* Only allow per-cpu swap if the ring buffer supports it */
7699 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
7700 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7705 if (tr->allocated_snapshot)
7706 ret = resize_buffer_duplicate_size(&tr->max_buffer,
7707 &tr->array_buffer, iter->cpu_file);
7709 ret = tracing_alloc_snapshot_instance(tr);
7712 /* Now, we're going to swap */
7713 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
7714 local_irq_disable();
7715 update_max_tr(tr, current, smp_processor_id(), NULL);
7718 smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer,
7723 if (tr->allocated_snapshot) {
7724 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7725 tracing_reset_online_cpus(&tr->max_buffer);
7727 tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
7737 mutex_unlock(&trace_types_lock);
7741 static int tracing_snapshot_release(struct inode *inode, struct file *file)
7743 struct seq_file *m = file->private_data;
7746 ret = tracing_release(inode, file);
7748 if (file->f_mode & FMODE_READ)
7751 /* If write only, the seq_file is just a stub */
7759 static int tracing_buffers_open(struct inode *inode, struct file *filp);
7760 static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
7761 size_t count, loff_t *ppos);
7762 static int tracing_buffers_release(struct inode *inode, struct file *file);
7763 static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
7764 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
7766 static int snapshot_raw_open(struct inode *inode, struct file *filp)
7768 struct ftrace_buffer_info *info;
7771 /* The following checks for tracefs lockdown */
7772 ret = tracing_buffers_open(inode, filp);
7776 info = filp->private_data;
7778 if (info->iter.trace->use_max_tr) {
7779 tracing_buffers_release(inode, filp);
7783 info->iter.snapshot = true;
7784 info->iter.array_buffer = &info->iter.tr->max_buffer;
7789 #endif /* CONFIG_TRACER_SNAPSHOT */
7792 static const struct file_operations tracing_thresh_fops = {
7793 .open = tracing_open_generic,
7794 .read = tracing_thresh_read,
7795 .write = tracing_thresh_write,
7796 .llseek = generic_file_llseek,
7799 #ifdef CONFIG_TRACER_MAX_TRACE
7800 static const struct file_operations tracing_max_lat_fops = {
7801 .open = tracing_open_generic_tr,
7802 .read = tracing_max_lat_read,
7803 .write = tracing_max_lat_write,
7804 .llseek = generic_file_llseek,
7805 .release = tracing_release_generic_tr,
7809 static const struct file_operations set_tracer_fops = {
7810 .open = tracing_open_generic_tr,
7811 .read = tracing_set_trace_read,
7812 .write = tracing_set_trace_write,
7813 .llseek = generic_file_llseek,
7814 .release = tracing_release_generic_tr,
7817 static const struct file_operations tracing_pipe_fops = {
7818 .open = tracing_open_pipe,
7819 .poll = tracing_poll_pipe,
7820 .read = tracing_read_pipe,
7821 .splice_read = tracing_splice_read_pipe,
7822 .release = tracing_release_pipe,
7823 .llseek = no_llseek,
7826 static const struct file_operations tracing_entries_fops = {
7827 .open = tracing_open_generic_tr,
7828 .read = tracing_entries_read,
7829 .write = tracing_entries_write,
7830 .llseek = generic_file_llseek,
7831 .release = tracing_release_generic_tr,
7834 static const struct file_operations tracing_total_entries_fops = {
7835 .open = tracing_open_generic_tr,
7836 .read = tracing_total_entries_read,
7837 .llseek = generic_file_llseek,
7838 .release = tracing_release_generic_tr,
7841 static const struct file_operations tracing_free_buffer_fops = {
7842 .open = tracing_open_generic_tr,
7843 .write = tracing_free_buffer_write,
7844 .release = tracing_free_buffer_release,
7847 static const struct file_operations tracing_mark_fops = {
7848 .open = tracing_mark_open,
7849 .write = tracing_mark_write,
7850 .release = tracing_release_generic_tr,
7853 static const struct file_operations tracing_mark_raw_fops = {
7854 .open = tracing_mark_open,
7855 .write = tracing_mark_raw_write,
7856 .release = tracing_release_generic_tr,
7859 static const struct file_operations trace_clock_fops = {
7860 .open = tracing_clock_open,
7862 .llseek = seq_lseek,
7863 .release = tracing_single_release_tr,
7864 .write = tracing_clock_write,
7867 static const struct file_operations trace_time_stamp_mode_fops = {
7868 .open = tracing_time_stamp_mode_open,
7870 .llseek = seq_lseek,
7871 .release = tracing_single_release_tr,
7874 #ifdef CONFIG_TRACER_SNAPSHOT
7875 static const struct file_operations snapshot_fops = {
7876 .open = tracing_snapshot_open,
7878 .write = tracing_snapshot_write,
7879 .llseek = tracing_lseek,
7880 .release = tracing_snapshot_release,
7883 static const struct file_operations snapshot_raw_fops = {
7884 .open = snapshot_raw_open,
7885 .read = tracing_buffers_read,
7886 .release = tracing_buffers_release,
7887 .splice_read = tracing_buffers_splice_read,
7888 .llseek = no_llseek,
7891 #endif /* CONFIG_TRACER_SNAPSHOT */
7894 * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
7895 * @filp: The active open file structure
7896 * @ubuf: The userspace provided buffer to read value into
7897 * @cnt: The maximum number of bytes to read
7898 * @ppos: The current "file" position
7900 * This function implements the write interface for a struct trace_min_max_param.
7901 * The filp->private_data must point to a trace_min_max_param structure that
7902 * defines where to write the value, the min and the max acceptable values,
7903 * and a lock to protect the write.
7906 trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
7908 struct trace_min_max_param *param = filp->private_data;
7915 err = kstrtoull_from_user(ubuf, cnt, 10, &val);
7920 mutex_lock(param->lock);
7922 if (param->min && val < *param->min)
7925 if (param->max && val > *param->max)
7932 mutex_unlock(param->lock);
7941 * trace_min_max_read - Read a u64 value from a trace_min_max_param struct
7942 * @filp: The active open file structure
7943 * @ubuf: The userspace provided buffer to read value into
7944 * @cnt: The maximum number of bytes to read
7945 * @ppos: The current "file" position
7947 * This function implements the read interface for a struct trace_min_max_param.
7948 * The filp->private_data must point to a trace_min_max_param struct with valid
7952 trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
7954 struct trace_min_max_param *param = filp->private_data;
7955 char buf[U64_STR_SIZE];
7964 if (cnt > sizeof(buf))
7967 len = snprintf(buf, sizeof(buf), "%llu\n", val);
7969 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
7972 const struct file_operations trace_min_max_fops = {
7973 .open = tracing_open_generic,
7974 .read = trace_min_max_read,
7975 .write = trace_min_max_write,
7978 #define TRACING_LOG_ERRS_MAX 8
7979 #define TRACING_LOG_LOC_MAX 128
7981 #define CMD_PREFIX " Command: "
7984 const char **errs; /* ptr to loc-specific array of err strings */
7985 u8 type; /* index into errs -> specific err string */
7986 u16 pos; /* caret position */
7990 struct tracing_log_err {
7991 struct list_head list;
7992 struct err_info info;
7993 char loc[TRACING_LOG_LOC_MAX]; /* err location */
7994 char *cmd; /* what caused err */
7997 static DEFINE_MUTEX(tracing_err_log_lock);
7999 static struct tracing_log_err *alloc_tracing_log_err(int len)
8001 struct tracing_log_err *err;
8003 err = kzalloc(sizeof(*err), GFP_KERNEL);
8005 return ERR_PTR(-ENOMEM);
8007 err->cmd = kzalloc(len, GFP_KERNEL);
8010 return ERR_PTR(-ENOMEM);
8016 static void free_tracing_log_err(struct tracing_log_err *err)
8022 static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr,
8025 struct tracing_log_err *err;
8028 if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
8029 err = alloc_tracing_log_err(len);
8030 if (PTR_ERR(err) != -ENOMEM)
8031 tr->n_err_log_entries++;
8035 cmd = kzalloc(len, GFP_KERNEL);
8037 return ERR_PTR(-ENOMEM);
8038 err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
8041 list_del(&err->list);
8047 * err_pos - find the position of a string within a command for error careting
8048 * @cmd: The tracing command that caused the error
8049 * @str: The string to position the caret at within @cmd
8051 * Finds the position of the first occurrence of @str within @cmd. The
8052 * return value can be passed to tracing_log_err() for caret placement
8055 * Returns the index within @cmd of the first occurrence of @str or 0
8056 * if @str was not found.
8058 unsigned int err_pos(char *cmd, const char *str)
8062 if (WARN_ON(!strlen(cmd)))
8065 found = strstr(cmd, str);
8073 * tracing_log_err - write an error to the tracing error log
8074 * @tr: The associated trace array for the error (NULL for top level array)
8075 * @loc: A string describing where the error occurred
8076 * @cmd: The tracing command that caused the error
8077 * @errs: The array of loc-specific static error strings
8078 * @type: The index into errs[], which produces the specific static err string
8079 * @pos: The position the caret should be placed in the cmd
8081 * Writes an error into tracing/error_log of the form:
8083 * <loc>: error: <text>
8087 * tracing/error_log is a small log file containing the last
8088 * TRACING_LOG_ERRS_MAX errors (8). Memory for errors isn't allocated
8089 * unless there has been a tracing error, and the error log can be
8090 * cleared and have its memory freed by writing the empty string in
8091 * truncation mode to it i.e. echo > tracing/error_log.
8093 * NOTE: the @errs array along with the @type param are used to
8094 * produce a static error string - this string is not copied and saved
8095 * when the error is logged - only a pointer to it is saved. See
8096 * existing callers for examples of how static strings are typically
8097 * defined for use with tracing_log_err().
8099 void tracing_log_err(struct trace_array *tr,
8100 const char *loc, const char *cmd,
8101 const char **errs, u8 type, u16 pos)
8103 struct tracing_log_err *err;
8109 len += sizeof(CMD_PREFIX) + 2 * sizeof("\n") + strlen(cmd) + 1;
8111 mutex_lock(&tracing_err_log_lock);
8112 err = get_tracing_log_err(tr, len);
8113 if (PTR_ERR(err) == -ENOMEM) {
8114 mutex_unlock(&tracing_err_log_lock);
8118 snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
8119 snprintf(err->cmd, len, "\n" CMD_PREFIX "%s\n", cmd);
8121 err->info.errs = errs;
8122 err->info.type = type;
8123 err->info.pos = pos;
8124 err->info.ts = local_clock();
8126 list_add_tail(&err->list, &tr->err_log);
8127 mutex_unlock(&tracing_err_log_lock);
8130 static void clear_tracing_err_log(struct trace_array *tr)
8132 struct tracing_log_err *err, *next;
8134 mutex_lock(&tracing_err_log_lock);
8135 list_for_each_entry_safe(err, next, &tr->err_log, list) {
8136 list_del(&err->list);
8137 free_tracing_log_err(err);
8140 tr->n_err_log_entries = 0;
8141 mutex_unlock(&tracing_err_log_lock);
8144 static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
8146 struct trace_array *tr = m->private;
8148 mutex_lock(&tracing_err_log_lock);
8150 return seq_list_start(&tr->err_log, *pos);
8153 static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
8155 struct trace_array *tr = m->private;
8157 return seq_list_next(v, &tr->err_log, pos);
8160 static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
8162 mutex_unlock(&tracing_err_log_lock);
8165 static void tracing_err_log_show_pos(struct seq_file *m, u16 pos)
8169 for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
8171 for (i = 0; i < pos; i++)
8176 static int tracing_err_log_seq_show(struct seq_file *m, void *v)
8178 struct tracing_log_err *err = v;
8181 const char *err_text = err->info.errs[err->info.type];
8182 u64 sec = err->info.ts;
8185 nsec = do_div(sec, NSEC_PER_SEC);
8186 seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
8187 err->loc, err_text);
8188 seq_printf(m, "%s", err->cmd);
8189 tracing_err_log_show_pos(m, err->info.pos);
8195 static const struct seq_operations tracing_err_log_seq_ops = {
8196 .start = tracing_err_log_seq_start,
8197 .next = tracing_err_log_seq_next,
8198 .stop = tracing_err_log_seq_stop,
8199 .show = tracing_err_log_seq_show
8202 static int tracing_err_log_open(struct inode *inode, struct file *file)
8204 struct trace_array *tr = inode->i_private;
8207 ret = tracing_check_open_get_tr(tr);
8211 /* If this file was opened for write, then erase contents */
8212 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
8213 clear_tracing_err_log(tr);
8215 if (file->f_mode & FMODE_READ) {
8216 ret = seq_open(file, &tracing_err_log_seq_ops);
8218 struct seq_file *m = file->private_data;
8221 trace_array_put(tr);
8227 static ssize_t tracing_err_log_write(struct file *file,
8228 const char __user *buffer,
8229 size_t count, loff_t *ppos)
8234 static int tracing_err_log_release(struct inode *inode, struct file *file)
8236 struct trace_array *tr = inode->i_private;
8238 trace_array_put(tr);
8240 if (file->f_mode & FMODE_READ)
8241 seq_release(inode, file);
8246 static const struct file_operations tracing_err_log_fops = {
8247 .open = tracing_err_log_open,
8248 .write = tracing_err_log_write,
8250 .llseek = tracing_lseek,
8251 .release = tracing_err_log_release,
8254 static int tracing_buffers_open(struct inode *inode, struct file *filp)
8256 struct trace_array *tr = inode->i_private;
8257 struct ftrace_buffer_info *info;
8260 ret = tracing_check_open_get_tr(tr);
8264 info = kvzalloc(sizeof(*info), GFP_KERNEL);
8266 trace_array_put(tr);
8270 mutex_lock(&trace_types_lock);
8273 info->iter.cpu_file = tracing_get_cpu(inode);
8274 info->iter.trace = tr->current_trace;
8275 info->iter.array_buffer = &tr->array_buffer;
8277 /* Force reading ring buffer for first read */
8278 info->read = (unsigned int)-1;
8280 filp->private_data = info;
8284 mutex_unlock(&trace_types_lock);
8286 ret = nonseekable_open(inode, filp);
8288 trace_array_put(tr);
8294 tracing_buffers_poll(struct file *filp, poll_table *poll_table)
8296 struct ftrace_buffer_info *info = filp->private_data;
8297 struct trace_iterator *iter = &info->iter;
8299 return trace_poll(iter, filp, poll_table);
8303 tracing_buffers_read(struct file *filp, char __user *ubuf,
8304 size_t count, loff_t *ppos)
8306 struct ftrace_buffer_info *info = filp->private_data;
8307 struct trace_iterator *iter = &info->iter;
8314 #ifdef CONFIG_TRACER_MAX_TRACE
8315 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8320 info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer,
8322 if (IS_ERR(info->spare)) {
8323 ret = PTR_ERR(info->spare);
8326 info->spare_cpu = iter->cpu_file;
8332 /* Do we have previous read data to read? */
8333 if (info->read < PAGE_SIZE)
8337 trace_access_lock(iter->cpu_file);
8338 ret = ring_buffer_read_page(iter->array_buffer->buffer,
8342 trace_access_unlock(iter->cpu_file);
8345 if (trace_empty(iter)) {
8346 if ((filp->f_flags & O_NONBLOCK))
8349 ret = wait_on_pipe(iter, 0);
8360 size = PAGE_SIZE - info->read;
8364 ret = copy_to_user(ubuf, info->spare + info->read, size);
8376 static int tracing_buffers_release(struct inode *inode, struct file *file)
8378 struct ftrace_buffer_info *info = file->private_data;
8379 struct trace_iterator *iter = &info->iter;
8381 mutex_lock(&trace_types_lock);
8383 iter->tr->trace_ref--;
8385 __trace_array_put(iter->tr);
8388 /* Make sure the waiters see the new wait_index */
8391 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
8394 ring_buffer_free_read_page(iter->array_buffer->buffer,
8395 info->spare_cpu, info->spare);
8398 mutex_unlock(&trace_types_lock);
8404 struct trace_buffer *buffer;
8407 refcount_t refcount;
8410 static void buffer_ref_release(struct buffer_ref *ref)
8412 if (!refcount_dec_and_test(&ref->refcount))
8414 ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
8418 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
8419 struct pipe_buffer *buf)
8421 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8423 buffer_ref_release(ref);
8427 static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
8428 struct pipe_buffer *buf)
8430 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8432 if (refcount_read(&ref->refcount) > INT_MAX/2)
8435 refcount_inc(&ref->refcount);
8439 /* Pipe buffer operations for a buffer. */
8440 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
8441 .release = buffer_pipe_buf_release,
8442 .get = buffer_pipe_buf_get,
8446 * Callback from splice_to_pipe(), if we need to release some pages
8447 * at the end of the spd in case we error'ed out in filling the pipe.
8449 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
8451 struct buffer_ref *ref =
8452 (struct buffer_ref *)spd->partial[i].private;
8454 buffer_ref_release(ref);
8455 spd->partial[i].private = 0;
8459 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
8460 struct pipe_inode_info *pipe, size_t len,
8463 struct ftrace_buffer_info *info = file->private_data;
8464 struct trace_iterator *iter = &info->iter;
8465 struct partial_page partial_def[PIPE_DEF_BUFFERS];
8466 struct page *pages_def[PIPE_DEF_BUFFERS];
8467 struct splice_pipe_desc spd = {
8469 .partial = partial_def,
8470 .nr_pages_max = PIPE_DEF_BUFFERS,
8471 .ops = &buffer_pipe_buf_ops,
8472 .spd_release = buffer_spd_release,
8474 struct buffer_ref *ref;
8478 #ifdef CONFIG_TRACER_MAX_TRACE
8479 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8483 if (*ppos & (PAGE_SIZE - 1))
8486 if (len & (PAGE_SIZE - 1)) {
8487 if (len < PAGE_SIZE)
8492 if (splice_grow_spd(pipe, &spd))
8496 trace_access_lock(iter->cpu_file);
8497 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8499 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
8503 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
8509 refcount_set(&ref->refcount, 1);
8510 ref->buffer = iter->array_buffer->buffer;
8511 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
8512 if (IS_ERR(ref->page)) {
8513 ret = PTR_ERR(ref->page);
8518 ref->cpu = iter->cpu_file;
8520 r = ring_buffer_read_page(ref->buffer, &ref->page,
8521 len, iter->cpu_file, 1);
8523 ring_buffer_free_read_page(ref->buffer, ref->cpu,
8529 page = virt_to_page(ref->page);
8531 spd.pages[i] = page;
8532 spd.partial[i].len = PAGE_SIZE;
8533 spd.partial[i].offset = 0;
8534 spd.partial[i].private = (unsigned long)ref;
8538 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8541 trace_access_unlock(iter->cpu_file);
8544 /* did we read anything? */
8545 if (!spd.nr_pages) {
8552 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
8555 wait_index = READ_ONCE(iter->wait_index);
8557 ret = wait_on_pipe(iter, iter->tr->buffer_percent);
8561 /* No need to wait after waking up when tracing is off */
8562 if (!tracer_tracing_is_on(iter->tr))
8565 /* Make sure we see the new wait_index */
8567 if (wait_index != iter->wait_index)
8573 ret = splice_to_pipe(pipe, &spd);
8575 splice_shrink_spd(&spd);
8580 /* An ioctl call with cmd 0 to the ring buffer file will wake up all waiters */
8581 static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
8583 struct ftrace_buffer_info *info = file->private_data;
8584 struct trace_iterator *iter = &info->iter;
8587 return -ENOIOCTLCMD;
8589 mutex_lock(&trace_types_lock);
8592 /* Make sure the waiters see the new wait_index */
8595 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
8597 mutex_unlock(&trace_types_lock);
8601 static const struct file_operations tracing_buffers_fops = {
8602 .open = tracing_buffers_open,
8603 .read = tracing_buffers_read,
8604 .poll = tracing_buffers_poll,
8605 .release = tracing_buffers_release,
8606 .splice_read = tracing_buffers_splice_read,
8607 .unlocked_ioctl = tracing_buffers_ioctl,
8608 .llseek = no_llseek,
8612 tracing_stats_read(struct file *filp, char __user *ubuf,
8613 size_t count, loff_t *ppos)
8615 struct inode *inode = file_inode(filp);
8616 struct trace_array *tr = inode->i_private;
8617 struct array_buffer *trace_buf = &tr->array_buffer;
8618 int cpu = tracing_get_cpu(inode);
8619 struct trace_seq *s;
8621 unsigned long long t;
8622 unsigned long usec_rem;
8624 s = kmalloc(sizeof(*s), GFP_KERNEL);
8630 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
8631 trace_seq_printf(s, "entries: %ld\n", cnt);
8633 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
8634 trace_seq_printf(s, "overrun: %ld\n", cnt);
8636 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
8637 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
8639 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
8640 trace_seq_printf(s, "bytes: %ld\n", cnt);
8642 if (trace_clocks[tr->clock_id].in_ns) {
8643 /* local or global for trace_clock */
8644 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8645 usec_rem = do_div(t, USEC_PER_SEC);
8646 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
8649 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer));
8650 usec_rem = do_div(t, USEC_PER_SEC);
8651 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
8653 /* counter or tsc mode for trace_clock */
8654 trace_seq_printf(s, "oldest event ts: %llu\n",
8655 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8657 trace_seq_printf(s, "now ts: %llu\n",
8658 ring_buffer_time_stamp(trace_buf->buffer));
8661 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
8662 trace_seq_printf(s, "dropped events: %ld\n", cnt);
8664 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
8665 trace_seq_printf(s, "read events: %ld\n", cnt);
8667 count = simple_read_from_buffer(ubuf, count, ppos,
8668 s->buffer, trace_seq_used(s));
8675 static const struct file_operations tracing_stats_fops = {
8676 .open = tracing_open_generic_tr,
8677 .read = tracing_stats_read,
8678 .llseek = generic_file_llseek,
8679 .release = tracing_release_generic_tr,
8682 #ifdef CONFIG_DYNAMIC_FTRACE
8685 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
8686 size_t cnt, loff_t *ppos)
8692 /* 256 should be plenty to hold the amount needed */
8693 buf = kmalloc(256, GFP_KERNEL);
8697 r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n",
8698 ftrace_update_tot_cnt,
8699 ftrace_number_of_pages,
8700 ftrace_number_of_groups);
8702 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8707 static const struct file_operations tracing_dyn_info_fops = {
8708 .open = tracing_open_generic,
8709 .read = tracing_read_dyn_info,
8710 .llseek = generic_file_llseek,
8712 #endif /* CONFIG_DYNAMIC_FTRACE */
8714 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
8716 ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
8717 struct trace_array *tr, struct ftrace_probe_ops *ops,
8720 tracing_snapshot_instance(tr);
8724 ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
8725 struct trace_array *tr, struct ftrace_probe_ops *ops,
8728 struct ftrace_func_mapper *mapper = data;
8732 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8742 tracing_snapshot_instance(tr);
8746 ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
8747 struct ftrace_probe_ops *ops, void *data)
8749 struct ftrace_func_mapper *mapper = data;
8752 seq_printf(m, "%ps:", (void *)ip);
8754 seq_puts(m, "snapshot");
8757 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8760 seq_printf(m, ":count=%ld\n", *count);
8762 seq_puts(m, ":unlimited\n");
8768 ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
8769 unsigned long ip, void *init_data, void **data)
8771 struct ftrace_func_mapper *mapper = *data;
8774 mapper = allocate_ftrace_func_mapper();
8780 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
8784 ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
8785 unsigned long ip, void *data)
8787 struct ftrace_func_mapper *mapper = data;
8792 free_ftrace_func_mapper(mapper, NULL);
8796 ftrace_func_mapper_remove_ip(mapper, ip);
8799 static struct ftrace_probe_ops snapshot_probe_ops = {
8800 .func = ftrace_snapshot,
8801 .print = ftrace_snapshot_print,
8804 static struct ftrace_probe_ops snapshot_count_probe_ops = {
8805 .func = ftrace_count_snapshot,
8806 .print = ftrace_snapshot_print,
8807 .init = ftrace_snapshot_init,
8808 .free = ftrace_snapshot_free,
8812 ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
8813 char *glob, char *cmd, char *param, int enable)
8815 struct ftrace_probe_ops *ops;
8816 void *count = (void *)-1;
8823 /* hash funcs only work with set_ftrace_filter */
8827 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
8830 return unregister_ftrace_function_probe_func(glob+1, tr, ops);
8835 number = strsep(¶m, ":");
8837 if (!strlen(number))
8841 * We use the callback data field (which is a pointer)
8844 ret = kstrtoul(number, 0, (unsigned long *)&count);
8849 ret = tracing_alloc_snapshot_instance(tr);
8853 ret = register_ftrace_function_probe(glob, tr, ops, count);
8856 return ret < 0 ? ret : 0;
8859 static struct ftrace_func_command ftrace_snapshot_cmd = {
8861 .func = ftrace_trace_snapshot_callback,
8864 static __init int register_snapshot_cmd(void)
8866 return register_ftrace_command(&ftrace_snapshot_cmd);
8869 static inline __init int register_snapshot_cmd(void) { return 0; }
8870 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
8872 static struct dentry *tracing_get_dentry(struct trace_array *tr)
8874 if (WARN_ON(!tr->dir))
8875 return ERR_PTR(-ENODEV);
8877 /* Top directory uses NULL as the parent */
8878 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
8881 /* All sub buffers have a descriptor */
8885 static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
8887 struct dentry *d_tracer;
8890 return tr->percpu_dir;
8892 d_tracer = tracing_get_dentry(tr);
8893 if (IS_ERR(d_tracer))
8896 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
8898 MEM_FAIL(!tr->percpu_dir,
8899 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
8901 return tr->percpu_dir;
8904 static struct dentry *
8905 trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
8906 void *data, long cpu, const struct file_operations *fops)
8908 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
8910 if (ret) /* See tracing_get_cpu() */
8911 d_inode(ret)->i_cdev = (void *)(cpu + 1);
8916 tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
8918 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
8919 struct dentry *d_cpu;
8920 char cpu_dir[30]; /* 30 characters should be more than enough */
8925 snprintf(cpu_dir, 30, "cpu%ld", cpu);
8926 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
8928 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
8932 /* per cpu trace_pipe */
8933 trace_create_cpu_file("trace_pipe", TRACE_MODE_READ, d_cpu,
8934 tr, cpu, &tracing_pipe_fops);
8937 trace_create_cpu_file("trace", TRACE_MODE_WRITE, d_cpu,
8938 tr, cpu, &tracing_fops);
8940 trace_create_cpu_file("trace_pipe_raw", TRACE_MODE_READ, d_cpu,
8941 tr, cpu, &tracing_buffers_fops);
8943 trace_create_cpu_file("stats", TRACE_MODE_READ, d_cpu,
8944 tr, cpu, &tracing_stats_fops);
8946 trace_create_cpu_file("buffer_size_kb", TRACE_MODE_READ, d_cpu,
8947 tr, cpu, &tracing_entries_fops);
8949 #ifdef CONFIG_TRACER_SNAPSHOT
8950 trace_create_cpu_file("snapshot", TRACE_MODE_WRITE, d_cpu,
8951 tr, cpu, &snapshot_fops);
8953 trace_create_cpu_file("snapshot_raw", TRACE_MODE_READ, d_cpu,
8954 tr, cpu, &snapshot_raw_fops);
8958 #ifdef CONFIG_FTRACE_SELFTEST
8959 /* Let selftest have access to static functions in this file */
8960 #include "trace_selftest.c"
8964 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
8967 struct trace_option_dentry *topt = filp->private_data;
8970 if (topt->flags->val & topt->opt->bit)
8975 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
8979 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
8982 struct trace_option_dentry *topt = filp->private_data;
8986 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8990 if (val != 0 && val != 1)
8993 if (!!(topt->flags->val & topt->opt->bit) != val) {
8994 mutex_lock(&trace_types_lock);
8995 ret = __set_tracer_option(topt->tr, topt->flags,
8997 mutex_unlock(&trace_types_lock);
9007 static int tracing_open_options(struct inode *inode, struct file *filp)
9009 struct trace_option_dentry *topt = inode->i_private;
9012 ret = tracing_check_open_get_tr(topt->tr);
9016 filp->private_data = inode->i_private;
9020 static int tracing_release_options(struct inode *inode, struct file *file)
9022 struct trace_option_dentry *topt = file->private_data;
9024 trace_array_put(topt->tr);
9028 static const struct file_operations trace_options_fops = {
9029 .open = tracing_open_options,
9030 .read = trace_options_read,
9031 .write = trace_options_write,
9032 .llseek = generic_file_llseek,
9033 .release = tracing_release_options,
9037 * In order to pass in both the trace_array descriptor as well as the index
9038 * to the flag that the trace option file represents, the trace_array
9039 * has a character array of trace_flags_index[], which holds the index
9040 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
9041 * The address of this character array is passed to the flag option file
9042 * read/write callbacks.
9044 * In order to extract both the index and the trace_array descriptor,
9045 * get_tr_index() uses the following algorithm.
9049 * As the pointer itself contains the address of the index (remember
9052 * Then to get the trace_array descriptor, by subtracting that index
9053 * from the ptr, we get to the start of the index itself.
9055 * ptr - idx == &index[0]
9057 * Then a simple container_of() from that pointer gets us to the
9058 * trace_array descriptor.
9060 static void get_tr_index(void *data, struct trace_array **ptr,
9061 unsigned int *pindex)
9063 *pindex = *(unsigned char *)data;
9065 *ptr = container_of(data - *pindex, struct trace_array,
9070 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
9073 void *tr_index = filp->private_data;
9074 struct trace_array *tr;
9078 get_tr_index(tr_index, &tr, &index);
9080 if (tr->trace_flags & (1 << index))
9085 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
9089 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
9092 void *tr_index = filp->private_data;
9093 struct trace_array *tr;
9098 get_tr_index(tr_index, &tr, &index);
9100 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9104 if (val != 0 && val != 1)
9107 mutex_lock(&event_mutex);
9108 mutex_lock(&trace_types_lock);
9109 ret = set_tracer_flag(tr, 1 << index, val);
9110 mutex_unlock(&trace_types_lock);
9111 mutex_unlock(&event_mutex);
9121 static const struct file_operations trace_options_core_fops = {
9122 .open = tracing_open_generic,
9123 .read = trace_options_core_read,
9124 .write = trace_options_core_write,
9125 .llseek = generic_file_llseek,
9128 struct dentry *trace_create_file(const char *name,
9130 struct dentry *parent,
9132 const struct file_operations *fops)
9136 ret = tracefs_create_file(name, mode, parent, data, fops);
9138 pr_warn("Could not create tracefs '%s' entry\n", name);
9144 static struct dentry *trace_options_init_dentry(struct trace_array *tr)
9146 struct dentry *d_tracer;
9151 d_tracer = tracing_get_dentry(tr);
9152 if (IS_ERR(d_tracer))
9155 tr->options = tracefs_create_dir("options", d_tracer);
9157 pr_warn("Could not create tracefs directory 'options'\n");
9165 create_trace_option_file(struct trace_array *tr,
9166 struct trace_option_dentry *topt,
9167 struct tracer_flags *flags,
9168 struct tracer_opt *opt)
9170 struct dentry *t_options;
9172 t_options = trace_options_init_dentry(tr);
9176 topt->flags = flags;
9180 topt->entry = trace_create_file(opt->name, TRACE_MODE_WRITE,
9181 t_options, topt, &trace_options_fops);
9186 create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
9188 struct trace_option_dentry *topts;
9189 struct trace_options *tr_topts;
9190 struct tracer_flags *flags;
9191 struct tracer_opt *opts;
9198 flags = tracer->flags;
9200 if (!flags || !flags->opts)
9204 * If this is an instance, only create flags for tracers
9205 * the instance may have.
9207 if (!trace_ok_for_array(tracer, tr))
9210 for (i = 0; i < tr->nr_topts; i++) {
9211 /* Make sure there's no duplicate flags. */
9212 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
9218 for (cnt = 0; opts[cnt].name; cnt++)
9221 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
9225 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
9232 tr->topts = tr_topts;
9233 tr->topts[tr->nr_topts].tracer = tracer;
9234 tr->topts[tr->nr_topts].topts = topts;
9237 for (cnt = 0; opts[cnt].name; cnt++) {
9238 create_trace_option_file(tr, &topts[cnt], flags,
9240 MEM_FAIL(topts[cnt].entry == NULL,
9241 "Failed to create trace option: %s",
9246 static struct dentry *
9247 create_trace_option_core_file(struct trace_array *tr,
9248 const char *option, long index)
9250 struct dentry *t_options;
9252 t_options = trace_options_init_dentry(tr);
9256 return trace_create_file(option, TRACE_MODE_WRITE, t_options,
9257 (void *)&tr->trace_flags_index[index],
9258 &trace_options_core_fops);
9261 static void create_trace_options_dir(struct trace_array *tr)
9263 struct dentry *t_options;
9264 bool top_level = tr == &global_trace;
9267 t_options = trace_options_init_dentry(tr);
9271 for (i = 0; trace_options[i]; i++) {
9273 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
9274 create_trace_option_core_file(tr, trace_options[i], i);
9279 rb_simple_read(struct file *filp, char __user *ubuf,
9280 size_t cnt, loff_t *ppos)
9282 struct trace_array *tr = filp->private_data;
9286 r = tracer_tracing_is_on(tr);
9287 r = sprintf(buf, "%d\n", r);
9289 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9293 rb_simple_write(struct file *filp, const char __user *ubuf,
9294 size_t cnt, loff_t *ppos)
9296 struct trace_array *tr = filp->private_data;
9297 struct trace_buffer *buffer = tr->array_buffer.buffer;
9301 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9306 mutex_lock(&trace_types_lock);
9307 if (!!val == tracer_tracing_is_on(tr)) {
9308 val = 0; /* do nothing */
9310 tracer_tracing_on(tr);
9311 if (tr->current_trace->start)
9312 tr->current_trace->start(tr);
9314 tracer_tracing_off(tr);
9315 if (tr->current_trace->stop)
9316 tr->current_trace->stop(tr);
9317 /* Wake up any waiters */
9318 ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS);
9320 mutex_unlock(&trace_types_lock);
9328 static const struct file_operations rb_simple_fops = {
9329 .open = tracing_open_generic_tr,
9330 .read = rb_simple_read,
9331 .write = rb_simple_write,
9332 .release = tracing_release_generic_tr,
9333 .llseek = default_llseek,
9337 buffer_percent_read(struct file *filp, char __user *ubuf,
9338 size_t cnt, loff_t *ppos)
9340 struct trace_array *tr = filp->private_data;
9344 r = tr->buffer_percent;
9345 r = sprintf(buf, "%d\n", r);
9347 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9351 buffer_percent_write(struct file *filp, const char __user *ubuf,
9352 size_t cnt, loff_t *ppos)
9354 struct trace_array *tr = filp->private_data;
9358 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9365 tr->buffer_percent = val;
9372 static const struct file_operations buffer_percent_fops = {
9373 .open = tracing_open_generic_tr,
9374 .read = buffer_percent_read,
9375 .write = buffer_percent_write,
9376 .release = tracing_release_generic_tr,
9377 .llseek = default_llseek,
9380 static struct dentry *trace_instance_dir;
9383 init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
9386 allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
9388 enum ring_buffer_flags rb_flags;
9390 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
9394 buf->buffer = ring_buffer_alloc(size, rb_flags);
9398 buf->data = alloc_percpu(struct trace_array_cpu);
9400 ring_buffer_free(buf->buffer);
9405 /* Allocate the first page for all buffers */
9406 set_buffer_entries(&tr->array_buffer,
9407 ring_buffer_size(tr->array_buffer.buffer, 0));
9412 static void free_trace_buffer(struct array_buffer *buf)
9415 ring_buffer_free(buf->buffer);
9417 free_percpu(buf->data);
9422 static int allocate_trace_buffers(struct trace_array *tr, int size)
9426 ret = allocate_trace_buffer(tr, &tr->array_buffer, size);
9430 #ifdef CONFIG_TRACER_MAX_TRACE
9431 ret = allocate_trace_buffer(tr, &tr->max_buffer,
9432 allocate_snapshot ? size : 1);
9433 if (MEM_FAIL(ret, "Failed to allocate trace buffer\n")) {
9434 free_trace_buffer(&tr->array_buffer);
9437 tr->allocated_snapshot = allocate_snapshot;
9439 allocate_snapshot = false;
9445 static void free_trace_buffers(struct trace_array *tr)
9450 free_trace_buffer(&tr->array_buffer);
9452 #ifdef CONFIG_TRACER_MAX_TRACE
9453 free_trace_buffer(&tr->max_buffer);
9457 static void init_trace_flags_index(struct trace_array *tr)
9461 /* Used by the trace options files */
9462 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
9463 tr->trace_flags_index[i] = i;
9466 static void __update_tracer_options(struct trace_array *tr)
9470 for (t = trace_types; t; t = t->next)
9471 add_tracer_options(tr, t);
9474 static void update_tracer_options(struct trace_array *tr)
9476 mutex_lock(&trace_types_lock);
9477 tracer_options_updated = true;
9478 __update_tracer_options(tr);
9479 mutex_unlock(&trace_types_lock);
9482 /* Must have trace_types_lock held */
9483 struct trace_array *trace_array_find(const char *instance)
9485 struct trace_array *tr, *found = NULL;
9487 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9488 if (tr->name && strcmp(tr->name, instance) == 0) {
9497 struct trace_array *trace_array_find_get(const char *instance)
9499 struct trace_array *tr;
9501 mutex_lock(&trace_types_lock);
9502 tr = trace_array_find(instance);
9505 mutex_unlock(&trace_types_lock);
9510 static int trace_array_create_dir(struct trace_array *tr)
9514 tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);
9518 ret = event_trace_add_tracer(tr->dir, tr);
9520 tracefs_remove(tr->dir);
9524 init_tracer_tracefs(tr, tr->dir);
9525 __update_tracer_options(tr);
9530 static struct trace_array *trace_array_create(const char *name)
9532 struct trace_array *tr;
9536 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
9538 return ERR_PTR(ret);
9540 tr->name = kstrdup(name, GFP_KERNEL);
9544 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
9547 if (!zalloc_cpumask_var(&tr->pipe_cpumask, GFP_KERNEL))
9550 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
9552 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
9554 raw_spin_lock_init(&tr->start_lock);
9556 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
9558 tr->current_trace = &nop_trace;
9560 INIT_LIST_HEAD(&tr->systems);
9561 INIT_LIST_HEAD(&tr->events);
9562 INIT_LIST_HEAD(&tr->hist_vars);
9563 INIT_LIST_HEAD(&tr->err_log);
9565 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
9568 if (ftrace_allocate_ftrace_ops(tr) < 0)
9571 ftrace_init_trace_array(tr);
9573 init_trace_flags_index(tr);
9575 if (trace_instance_dir) {
9576 ret = trace_array_create_dir(tr);
9580 __trace_early_add_events(tr);
9582 list_add(&tr->list, &ftrace_trace_arrays);
9589 ftrace_free_ftrace_ops(tr);
9590 free_trace_buffers(tr);
9591 free_cpumask_var(tr->pipe_cpumask);
9592 free_cpumask_var(tr->tracing_cpumask);
9596 return ERR_PTR(ret);
9599 static int instance_mkdir(const char *name)
9601 struct trace_array *tr;
9604 mutex_lock(&event_mutex);
9605 mutex_lock(&trace_types_lock);
9608 if (trace_array_find(name))
9611 tr = trace_array_create(name);
9613 ret = PTR_ERR_OR_ZERO(tr);
9616 mutex_unlock(&trace_types_lock);
9617 mutex_unlock(&event_mutex);
9622 * trace_array_get_by_name - Create/Lookup a trace array, given its name.
9623 * @name: The name of the trace array to be looked up/created.
9625 * Returns pointer to trace array with given name.
9626 * NULL, if it cannot be created.
9628 * NOTE: This function increments the reference counter associated with the
9629 * trace array returned. This makes sure it cannot be freed while in use.
9630 * Use trace_array_put() once the trace array is no longer needed.
9631 * If the trace_array is to be freed, trace_array_destroy() needs to
9632 * be called after the trace_array_put(), or simply let user space delete
9633 * it from the tracefs instances directory. But until the
9634 * trace_array_put() is called, user space can not delete it.
9637 struct trace_array *trace_array_get_by_name(const char *name)
9639 struct trace_array *tr;
9641 mutex_lock(&event_mutex);
9642 mutex_lock(&trace_types_lock);
9644 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9645 if (tr->name && strcmp(tr->name, name) == 0)
9649 tr = trace_array_create(name);
9657 mutex_unlock(&trace_types_lock);
9658 mutex_unlock(&event_mutex);
9661 EXPORT_SYMBOL_GPL(trace_array_get_by_name);
9663 static int __remove_instance(struct trace_array *tr)
9667 /* Reference counter for a newly created trace array = 1. */
9668 if (tr->ref > 1 || (tr->current_trace && tr->trace_ref))
9671 list_del(&tr->list);
9673 /* Disable all the flags that were enabled coming in */
9674 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
9675 if ((1 << i) & ZEROED_TRACE_FLAGS)
9676 set_tracer_flag(tr, 1 << i, 0);
9679 tracing_set_nop(tr);
9680 clear_ftrace_function_probes(tr);
9681 event_trace_del_tracer(tr);
9682 ftrace_clear_pids(tr);
9683 ftrace_destroy_function_files(tr);
9684 tracefs_remove(tr->dir);
9685 free_percpu(tr->last_func_repeats);
9686 free_trace_buffers(tr);
9687 clear_tracing_err_log(tr);
9689 for (i = 0; i < tr->nr_topts; i++) {
9690 kfree(tr->topts[i].topts);
9694 free_cpumask_var(tr->pipe_cpumask);
9695 free_cpumask_var(tr->tracing_cpumask);
9702 int trace_array_destroy(struct trace_array *this_tr)
9704 struct trace_array *tr;
9710 mutex_lock(&event_mutex);
9711 mutex_lock(&trace_types_lock);
9715 /* Making sure trace array exists before destroying it. */
9716 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9717 if (tr == this_tr) {
9718 ret = __remove_instance(tr);
9723 mutex_unlock(&trace_types_lock);
9724 mutex_unlock(&event_mutex);
9728 EXPORT_SYMBOL_GPL(trace_array_destroy);
9730 static int instance_rmdir(const char *name)
9732 struct trace_array *tr;
9735 mutex_lock(&event_mutex);
9736 mutex_lock(&trace_types_lock);
9739 tr = trace_array_find(name);
9741 ret = __remove_instance(tr);
9743 mutex_unlock(&trace_types_lock);
9744 mutex_unlock(&event_mutex);
9749 static __init void create_trace_instances(struct dentry *d_tracer)
9751 struct trace_array *tr;
9753 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
9756 if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
9759 mutex_lock(&event_mutex);
9760 mutex_lock(&trace_types_lock);
9762 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9765 if (MEM_FAIL(trace_array_create_dir(tr) < 0,
9766 "Failed to create instance directory\n"))
9770 mutex_unlock(&trace_types_lock);
9771 mutex_unlock(&event_mutex);
9775 init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
9777 struct trace_event_file *file;
9780 trace_create_file("available_tracers", TRACE_MODE_READ, d_tracer,
9781 tr, &show_traces_fops);
9783 trace_create_file("current_tracer", TRACE_MODE_WRITE, d_tracer,
9784 tr, &set_tracer_fops);
9786 trace_create_file("tracing_cpumask", TRACE_MODE_WRITE, d_tracer,
9787 tr, &tracing_cpumask_fops);
9789 trace_create_file("trace_options", TRACE_MODE_WRITE, d_tracer,
9790 tr, &tracing_iter_fops);
9792 trace_create_file("trace", TRACE_MODE_WRITE, d_tracer,
9795 trace_create_file("trace_pipe", TRACE_MODE_READ, d_tracer,
9796 tr, &tracing_pipe_fops);
9798 trace_create_file("buffer_size_kb", TRACE_MODE_WRITE, d_tracer,
9799 tr, &tracing_entries_fops);
9801 trace_create_file("buffer_total_size_kb", TRACE_MODE_READ, d_tracer,
9802 tr, &tracing_total_entries_fops);
9804 trace_create_file("free_buffer", 0200, d_tracer,
9805 tr, &tracing_free_buffer_fops);
9807 trace_create_file("trace_marker", 0220, d_tracer,
9808 tr, &tracing_mark_fops);
9810 file = __find_event_file(tr, "ftrace", "print");
9811 if (file && file->ef)
9812 eventfs_add_file("trigger", TRACE_MODE_WRITE, file->ef,
9813 file, &event_trigger_fops);
9814 tr->trace_marker_file = file;
9816 trace_create_file("trace_marker_raw", 0220, d_tracer,
9817 tr, &tracing_mark_raw_fops);
9819 trace_create_file("trace_clock", TRACE_MODE_WRITE, d_tracer, tr,
9822 trace_create_file("tracing_on", TRACE_MODE_WRITE, d_tracer,
9823 tr, &rb_simple_fops);
9825 trace_create_file("timestamp_mode", TRACE_MODE_READ, d_tracer, tr,
9826 &trace_time_stamp_mode_fops);
9828 tr->buffer_percent = 50;
9830 trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
9831 tr, &buffer_percent_fops);
9833 create_trace_options_dir(tr);
9835 #ifdef CONFIG_TRACER_MAX_TRACE
9836 trace_create_maxlat_file(tr, d_tracer);
9839 if (ftrace_create_function_files(tr, d_tracer))
9840 MEM_FAIL(1, "Could not allocate function filter files");
9842 #ifdef CONFIG_TRACER_SNAPSHOT
9843 trace_create_file("snapshot", TRACE_MODE_WRITE, d_tracer,
9844 tr, &snapshot_fops);
9847 trace_create_file("error_log", TRACE_MODE_WRITE, d_tracer,
9848 tr, &tracing_err_log_fops);
9850 for_each_tracing_cpu(cpu)
9851 tracing_init_tracefs_percpu(tr, cpu);
9853 ftrace_init_tracefs(tr, d_tracer);
9856 static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
9858 struct vfsmount *mnt;
9859 struct file_system_type *type;
9862 * To maintain backward compatibility for tools that mount
9863 * debugfs to get to the tracing facility, tracefs is automatically
9864 * mounted to the debugfs/tracing directory.
9866 type = get_fs_type("tracefs");
9869 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
9870 put_filesystem(type);
9879 * tracing_init_dentry - initialize top level trace array
9881 * This is called when creating files or directories in the tracing
9882 * directory. It is called via fs_initcall() by any of the boot up code
9883 * and expects to return the dentry of the top level tracing directory.
9885 int tracing_init_dentry(void)
9887 struct trace_array *tr = &global_trace;
9889 if (security_locked_down(LOCKDOWN_TRACEFS)) {
9890 pr_warn("Tracing disabled due to lockdown\n");
9894 /* The top level trace array uses NULL as parent */
9898 if (WARN_ON(!tracefs_initialized()))
9902 * As there may still be users that expect the tracing
9903 * files to exist in debugfs/tracing, we must automount
9904 * the tracefs file system there, so older tools still
9905 * work with the newer kernel.
9907 tr->dir = debugfs_create_automount("tracing", NULL,
9908 trace_automount, NULL);
9913 extern struct trace_eval_map *__start_ftrace_eval_maps[];
9914 extern struct trace_eval_map *__stop_ftrace_eval_maps[];
9916 static struct workqueue_struct *eval_map_wq __initdata;
9917 static struct work_struct eval_map_work __initdata;
9918 static struct work_struct tracerfs_init_work __initdata;
9920 static void __init eval_map_work_func(struct work_struct *work)
9924 len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
9925 trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
9928 static int __init trace_eval_init(void)
9930 INIT_WORK(&eval_map_work, eval_map_work_func);
9932 eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0);
9934 pr_err("Unable to allocate eval_map_wq\n");
9936 eval_map_work_func(&eval_map_work);
9940 queue_work(eval_map_wq, &eval_map_work);
9944 subsys_initcall(trace_eval_init);
9946 static int __init trace_eval_sync(void)
9948 /* Make sure the eval map updates are finished */
9950 destroy_workqueue(eval_map_wq);
9954 late_initcall_sync(trace_eval_sync);
9957 #ifdef CONFIG_MODULES
9958 static void trace_module_add_evals(struct module *mod)
9960 if (!mod->num_trace_evals)
9964 * Modules with bad taint do not have events created, do
9965 * not bother with enums either.
9967 if (trace_module_has_bad_taint(mod))
9970 trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
9973 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
9974 static void trace_module_remove_evals(struct module *mod)
9976 union trace_eval_map_item *map;
9977 union trace_eval_map_item **last = &trace_eval_maps;
9979 if (!mod->num_trace_evals)
9982 mutex_lock(&trace_eval_mutex);
9984 map = trace_eval_maps;
9987 if (map->head.mod == mod)
9989 map = trace_eval_jmp_to_tail(map);
9990 last = &map->tail.next;
9991 map = map->tail.next;
9996 *last = trace_eval_jmp_to_tail(map)->tail.next;
9999 mutex_unlock(&trace_eval_mutex);
10002 static inline void trace_module_remove_evals(struct module *mod) { }
10003 #endif /* CONFIG_TRACE_EVAL_MAP_FILE */
10005 static int trace_module_notify(struct notifier_block *self,
10006 unsigned long val, void *data)
10008 struct module *mod = data;
10011 case MODULE_STATE_COMING:
10012 trace_module_add_evals(mod);
10014 case MODULE_STATE_GOING:
10015 trace_module_remove_evals(mod);
10022 static struct notifier_block trace_module_nb = {
10023 .notifier_call = trace_module_notify,
10026 #endif /* CONFIG_MODULES */
10028 static __init void tracer_init_tracefs_work_func(struct work_struct *work)
10031 event_trace_init();
10033 init_tracer_tracefs(&global_trace, NULL);
10034 ftrace_init_tracefs_toplevel(&global_trace, NULL);
10036 trace_create_file("tracing_thresh", TRACE_MODE_WRITE, NULL,
10037 &global_trace, &tracing_thresh_fops);
10039 trace_create_file("README", TRACE_MODE_READ, NULL,
10040 NULL, &tracing_readme_fops);
10042 trace_create_file("saved_cmdlines", TRACE_MODE_READ, NULL,
10043 NULL, &tracing_saved_cmdlines_fops);
10045 trace_create_file("saved_cmdlines_size", TRACE_MODE_WRITE, NULL,
10046 NULL, &tracing_saved_cmdlines_size_fops);
10048 trace_create_file("saved_tgids", TRACE_MODE_READ, NULL,
10049 NULL, &tracing_saved_tgids_fops);
10051 trace_create_eval_file(NULL);
10053 #ifdef CONFIG_MODULES
10054 register_module_notifier(&trace_module_nb);
10057 #ifdef CONFIG_DYNAMIC_FTRACE
10058 trace_create_file("dyn_ftrace_total_info", TRACE_MODE_READ, NULL,
10059 NULL, &tracing_dyn_info_fops);
10062 create_trace_instances(NULL);
10064 update_tracer_options(&global_trace);
10067 static __init int tracer_init_tracefs(void)
10071 trace_access_lock_init();
10073 ret = tracing_init_dentry();
10078 INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func);
10079 queue_work(eval_map_wq, &tracerfs_init_work);
10081 tracer_init_tracefs_work_func(NULL);
10084 rv_init_interface();
10089 fs_initcall(tracer_init_tracefs);
10091 static int trace_die_panic_handler(struct notifier_block *self,
10092 unsigned long ev, void *unused);
10094 static struct notifier_block trace_panic_notifier = {
10095 .notifier_call = trace_die_panic_handler,
10096 .priority = INT_MAX - 1,
10099 static struct notifier_block trace_die_notifier = {
10100 .notifier_call = trace_die_panic_handler,
10101 .priority = INT_MAX - 1,
10105 * The idea is to execute the following die/panic callback early, in order
10106 * to avoid showing irrelevant information in the trace (like other panic
10107 * notifier functions); we are the 2nd to run, after hung_task/rcu_stall
10108 * warnings get disabled (to prevent potential log flooding).
10110 static int trace_die_panic_handler(struct notifier_block *self,
10111 unsigned long ev, void *unused)
10113 if (!ftrace_dump_on_oops)
10114 return NOTIFY_DONE;
10116 /* The die notifier requires DIE_OOPS to trigger */
10117 if (self == &trace_die_notifier && ev != DIE_OOPS)
10118 return NOTIFY_DONE;
10120 ftrace_dump(ftrace_dump_on_oops);
10122 return NOTIFY_DONE;
10126 * printk is set to max of 1024, we really don't need it that big.
10127 * Nothing should be printing 1000 characters anyway.
10129 #define TRACE_MAX_PRINT 1000
10132 * Define here KERN_TRACE so that we have one place to modify
10133 * it if we decide to change what log level the ftrace dump
10136 #define KERN_TRACE KERN_EMERG
10139 trace_printk_seq(struct trace_seq *s)
10141 /* Probably should print a warning here. */
10142 if (s->seq.len >= TRACE_MAX_PRINT)
10143 s->seq.len = TRACE_MAX_PRINT;
10146 * More paranoid code. Although the buffer size is set to
10147 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
10148 * an extra layer of protection.
10150 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
10151 s->seq.len = s->seq.size - 1;
10153 /* should be zero ended, but we are paranoid. */
10154 s->buffer[s->seq.len] = 0;
10156 printk(KERN_TRACE "%s", s->buffer);
10161 void trace_init_global_iter(struct trace_iterator *iter)
10163 iter->tr = &global_trace;
10164 iter->trace = iter->tr->current_trace;
10165 iter->cpu_file = RING_BUFFER_ALL_CPUS;
10166 iter->array_buffer = &global_trace.array_buffer;
10168 if (iter->trace && iter->trace->open)
10169 iter->trace->open(iter);
10171 /* Annotate start of buffers if we had overruns */
10172 if (ring_buffer_overruns(iter->array_buffer->buffer))
10173 iter->iter_flags |= TRACE_FILE_ANNOTATE;
10175 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
10176 if (trace_clocks[iter->tr->clock_id].in_ns)
10177 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
10179 /* Can not use kmalloc for iter.temp and iter.fmt */
10180 iter->temp = static_temp_buf;
10181 iter->temp_size = STATIC_TEMP_BUF_SIZE;
10182 iter->fmt = static_fmt_buf;
10183 iter->fmt_size = STATIC_FMT_BUF_SIZE;
10186 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
10188 /* use static because iter can be a bit big for the stack */
10189 static struct trace_iterator iter;
10190 static atomic_t dump_running;
10191 struct trace_array *tr = &global_trace;
10192 unsigned int old_userobj;
10193 unsigned long flags;
10196 /* Only allow one dump user at a time. */
10197 if (atomic_inc_return(&dump_running) != 1) {
10198 atomic_dec(&dump_running);
10203 * Always turn off tracing when we dump.
10204 * We don't need to show trace output of what happens
10205 * between multiple crashes.
10207 * If the user does a sysrq-z, then they can re-enable
10208 * tracing with echo 1 > tracing_on.
10212 local_irq_save(flags);
10214 /* Simulate the iterator */
10215 trace_init_global_iter(&iter);
10217 for_each_tracing_cpu(cpu) {
10218 atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10221 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
10223 /* don't look at user memory in panic mode */
10224 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
10226 switch (oops_dump_mode) {
10228 iter.cpu_file = RING_BUFFER_ALL_CPUS;
10231 iter.cpu_file = raw_smp_processor_id();
10236 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
10237 iter.cpu_file = RING_BUFFER_ALL_CPUS;
10240 printk(KERN_TRACE "Dumping ftrace buffer:\n");
10242 /* Did function tracer already get disabled? */
10243 if (ftrace_is_dead()) {
10244 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
10245 printk("# MAY BE MISSING FUNCTION EVENTS\n");
10249 * We need to stop all tracing on all CPUS to read
10250 * the next buffer. This is a bit expensive, but is
10251 * not done often. We fill all what we can read,
10252 * and then release the locks again.
10255 while (!trace_empty(&iter)) {
10258 printk(KERN_TRACE "---------------------------------\n");
10262 trace_iterator_reset(&iter);
10263 iter.iter_flags |= TRACE_FILE_LAT_FMT;
10265 if (trace_find_next_entry_inc(&iter) != NULL) {
10268 ret = print_trace_line(&iter);
10269 if (ret != TRACE_TYPE_NO_CONSUME)
10270 trace_consume(&iter);
10272 touch_nmi_watchdog();
10274 trace_printk_seq(&iter.seq);
10278 printk(KERN_TRACE " (ftrace buffer empty)\n");
10280 printk(KERN_TRACE "---------------------------------\n");
10283 tr->trace_flags |= old_userobj;
10285 for_each_tracing_cpu(cpu) {
10286 atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10288 atomic_dec(&dump_running);
10289 local_irq_restore(flags);
10291 EXPORT_SYMBOL_GPL(ftrace_dump);
10293 #define WRITE_BUFSIZE 4096
10295 ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
10296 size_t count, loff_t *ppos,
10297 int (*createfn)(const char *))
10299 char *kbuf, *buf, *tmp;
10304 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
10308 while (done < count) {
10309 size = count - done;
10311 if (size >= WRITE_BUFSIZE)
10312 size = WRITE_BUFSIZE - 1;
10314 if (copy_from_user(kbuf, buffer + done, size)) {
10321 tmp = strchr(buf, '\n');
10324 size = tmp - buf + 1;
10326 size = strlen(buf);
10327 if (done + size < count) {
10330 /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
10331 pr_warn("Line length is too long: Should be less than %d\n",
10332 WRITE_BUFSIZE - 2);
10339 /* Remove comments */
10340 tmp = strchr(buf, '#');
10345 ret = createfn(buf);
10350 } while (done < count);
10360 #ifdef CONFIG_TRACER_MAX_TRACE
10361 __init static bool tr_needs_alloc_snapshot(const char *name)
10364 int len = strlen(name);
10367 if (!boot_snapshot_index)
10370 if (strncmp(name, boot_snapshot_info, len) == 0 &&
10371 boot_snapshot_info[len] == '\t')
10374 test = kmalloc(strlen(name) + 3, GFP_KERNEL);
10378 sprintf(test, "\t%s\t", name);
10379 ret = strstr(boot_snapshot_info, test) == NULL;
10384 __init static void do_allocate_snapshot(const char *name)
10386 if (!tr_needs_alloc_snapshot(name))
10390 * When allocate_snapshot is set, the next call to
10391 * allocate_trace_buffers() (called by trace_array_get_by_name())
10392 * will allocate the snapshot buffer. That will alse clear
10395 allocate_snapshot = true;
10398 static inline void do_allocate_snapshot(const char *name) { }
10401 __init static void enable_instances(void)
10403 struct trace_array *tr;
10408 /* A tab is always appended */
10409 boot_instance_info[boot_instance_index - 1] = '\0';
10410 str = boot_instance_info;
10412 while ((curr_str = strsep(&str, "\t"))) {
10414 tok = strsep(&curr_str, ",");
10416 if (IS_ENABLED(CONFIG_TRACER_MAX_TRACE))
10417 do_allocate_snapshot(tok);
10419 tr = trace_array_get_by_name(tok);
10421 pr_warn("Failed to create instance buffer %s\n", curr_str);
10424 /* Allow user space to delete it */
10425 trace_array_put(tr);
10427 while ((tok = strsep(&curr_str, ","))) {
10428 early_enable_events(tr, tok, true);
10433 __init static int tracer_alloc_buffers(void)
10439 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10440 pr_warn("Tracing disabled due to lockdown\n");
10445 * Make sure we don't accidentally add more trace options
10446 * than we have bits for.
10448 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
10450 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
10453 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
10454 goto out_free_buffer_mask;
10456 /* Only allocate trace_printk buffers if a trace_printk exists */
10457 if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
10458 /* Must be called before global_trace.buffer is allocated */
10459 trace_printk_init_buffers();
10461 /* To save memory, keep the ring buffer size to its minimum */
10462 if (ring_buffer_expanded)
10463 ring_buf_size = trace_buf_size;
10467 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
10468 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
10470 raw_spin_lock_init(&global_trace.start_lock);
10473 * The prepare callbacks allocates some memory for the ring buffer. We
10474 * don't free the buffer if the CPU goes down. If we were to free
10475 * the buffer, then the user would lose any trace that was in the
10476 * buffer. The memory will be removed once the "instance" is removed.
10478 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
10479 "trace/RB:prepare", trace_rb_cpu_prepare,
10482 goto out_free_cpumask;
10483 /* Used for event triggers */
10485 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
10487 goto out_rm_hp_state;
10489 if (trace_create_savedcmd() < 0)
10490 goto out_free_temp_buffer;
10492 if (!zalloc_cpumask_var(&global_trace.pipe_cpumask, GFP_KERNEL))
10493 goto out_free_savedcmd;
10495 /* TODO: make the number of buffers hot pluggable with CPUS */
10496 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
10497 MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n");
10498 goto out_free_pipe_cpumask;
10500 if (global_trace.buffer_disabled)
10503 if (trace_boot_clock) {
10504 ret = tracing_set_clock(&global_trace, trace_boot_clock);
10506 pr_warn("Trace clock %s not defined, going back to default\n",
10511 * register_tracer() might reference current_trace, so it
10512 * needs to be set before we register anything. This is
10513 * just a bootstrap of current_trace anyway.
10515 global_trace.current_trace = &nop_trace;
10517 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
10519 ftrace_init_global_array_ops(&global_trace);
10521 init_trace_flags_index(&global_trace);
10523 register_tracer(&nop_trace);
10525 /* Function tracing may start here (via kernel command line) */
10526 init_function_trace();
10528 /* All seems OK, enable tracing */
10529 tracing_disabled = 0;
10531 atomic_notifier_chain_register(&panic_notifier_list,
10532 &trace_panic_notifier);
10534 register_die_notifier(&trace_die_notifier);
10536 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
10538 INIT_LIST_HEAD(&global_trace.systems);
10539 INIT_LIST_HEAD(&global_trace.events);
10540 INIT_LIST_HEAD(&global_trace.hist_vars);
10541 INIT_LIST_HEAD(&global_trace.err_log);
10542 list_add(&global_trace.list, &ftrace_trace_arrays);
10544 apply_trace_boot_options();
10546 register_snapshot_cmd();
10552 out_free_pipe_cpumask:
10553 free_cpumask_var(global_trace.pipe_cpumask);
10555 free_saved_cmdlines_buffer(savedcmd);
10556 out_free_temp_buffer:
10557 ring_buffer_free(temp_buffer);
10559 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
10561 free_cpumask_var(global_trace.tracing_cpumask);
10562 out_free_buffer_mask:
10563 free_cpumask_var(tracing_buffer_mask);
10568 void __init ftrace_boot_snapshot(void)
10570 #ifdef CONFIG_TRACER_MAX_TRACE
10571 struct trace_array *tr;
10573 if (!snapshot_at_boot)
10576 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
10577 if (!tr->allocated_snapshot)
10580 tracing_snapshot_instance(tr);
10581 trace_array_puts(tr, "** Boot snapshot taken **\n");
10586 void __init early_trace_init(void)
10588 if (tracepoint_printk) {
10589 tracepoint_print_iter =
10590 kzalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
10591 if (MEM_FAIL(!tracepoint_print_iter,
10592 "Failed to allocate trace iterator\n"))
10593 tracepoint_printk = 0;
10595 static_key_enable(&tracepoint_printk_key.key);
10597 tracer_alloc_buffers();
10602 void __init trace_init(void)
10604 trace_event_init();
10606 if (boot_instance_index)
10607 enable_instances();
10610 __init static void clear_boot_tracer(void)
10613 * The default tracer at boot buffer is an init section.
10614 * This function is called in lateinit. If we did not
10615 * find the boot tracer, then clear it out, to prevent
10616 * later registration from accessing the buffer that is
10617 * about to be freed.
10619 if (!default_bootup_tracer)
10622 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
10623 default_bootup_tracer);
10624 default_bootup_tracer = NULL;
10627 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
10628 __init static void tracing_set_default_clock(void)
10630 /* sched_clock_stable() is determined in late_initcall */
10631 if (!trace_boot_clock && !sched_clock_stable()) {
10632 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10633 pr_warn("Can not set tracing clock due to lockdown\n");
10637 printk(KERN_WARNING
10638 "Unstable clock detected, switching default tracing clock to \"global\"\n"
10639 "If you want to keep using the local clock, then add:\n"
10640 " \"trace_clock=local\"\n"
10641 "on the kernel command line\n");
10642 tracing_set_clock(&global_trace, "global");
10646 static inline void tracing_set_default_clock(void) { }
10649 __init static int late_trace_init(void)
10651 if (tracepoint_printk && tracepoint_printk_stop_on_boot) {
10652 static_key_disable(&tracepoint_printk_key.key);
10653 tracepoint_printk = 0;
10656 tracing_set_default_clock();
10657 clear_boot_tracer();
10661 late_initcall_sync(late_trace_init);