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",
1775 d_tracer, &tr->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->max_latency, &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 iter->trace = tr->current_trace;
4195 mutex_unlock(&trace_types_lock);
4197 #ifdef CONFIG_TRACER_MAX_TRACE
4198 if (iter->snapshot && iter->trace->use_max_tr)
4199 return ERR_PTR(-EBUSY);
4202 if (*pos != iter->pos) {
4207 if (cpu_file == RING_BUFFER_ALL_CPUS) {
4208 for_each_tracing_cpu(cpu)
4209 tracing_iter_reset(iter, cpu);
4211 tracing_iter_reset(iter, cpu_file);
4214 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
4219 * If we overflowed the seq_file before, then we want
4220 * to just reuse the trace_seq buffer again.
4226 p = s_next(m, p, &l);
4230 trace_event_read_lock();
4231 trace_access_lock(cpu_file);
4235 static void s_stop(struct seq_file *m, void *p)
4237 struct trace_iterator *iter = m->private;
4239 #ifdef CONFIG_TRACER_MAX_TRACE
4240 if (iter->snapshot && iter->trace->use_max_tr)
4244 trace_access_unlock(iter->cpu_file);
4245 trace_event_read_unlock();
4249 get_total_entries_cpu(struct array_buffer *buf, unsigned long *total,
4250 unsigned long *entries, int cpu)
4252 unsigned long count;
4254 count = ring_buffer_entries_cpu(buf->buffer, cpu);
4256 * If this buffer has skipped entries, then we hold all
4257 * entries for the trace and we need to ignore the
4258 * ones before the time stamp.
4260 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
4261 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
4262 /* total is the same as the entries */
4266 ring_buffer_overrun_cpu(buf->buffer, cpu);
4271 get_total_entries(struct array_buffer *buf,
4272 unsigned long *total, unsigned long *entries)
4280 for_each_tracing_cpu(cpu) {
4281 get_total_entries_cpu(buf, &t, &e, cpu);
4287 unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
4289 unsigned long total, entries;
4294 get_total_entries_cpu(&tr->array_buffer, &total, &entries, cpu);
4299 unsigned long trace_total_entries(struct trace_array *tr)
4301 unsigned long total, entries;
4306 get_total_entries(&tr->array_buffer, &total, &entries);
4311 static void print_lat_help_header(struct seq_file *m)
4313 seq_puts(m, "# _------=> CPU# \n"
4314 "# / _-----=> irqs-off/BH-disabled\n"
4315 "# | / _----=> need-resched \n"
4316 "# || / _---=> hardirq/softirq \n"
4317 "# ||| / _--=> preempt-depth \n"
4318 "# |||| / _-=> migrate-disable \n"
4319 "# ||||| / delay \n"
4320 "# cmd pid |||||| time | caller \n"
4321 "# \\ / |||||| \\ | / \n");
4324 static void print_event_info(struct array_buffer *buf, struct seq_file *m)
4326 unsigned long total;
4327 unsigned long entries;
4329 get_total_entries(buf, &total, &entries);
4330 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
4331 entries, total, num_online_cpus());
4335 static void print_func_help_header(struct array_buffer *buf, struct seq_file *m,
4338 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4340 print_event_info(buf, m);
4342 seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? " TGID " : "");
4343 seq_printf(m, "# | | %s | | |\n", tgid ? " | " : "");
4346 static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file *m,
4349 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4350 static const char space[] = " ";
4351 int prec = tgid ? 12 : 2;
4353 print_event_info(buf, m);
4355 seq_printf(m, "# %.*s _-----=> irqs-off/BH-disabled\n", prec, space);
4356 seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space);
4357 seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space);
4358 seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space);
4359 seq_printf(m, "# %.*s||| / _-=> migrate-disable\n", prec, space);
4360 seq_printf(m, "# %.*s|||| / delay\n", prec, space);
4361 seq_printf(m, "# TASK-PID %.*s CPU# ||||| TIMESTAMP FUNCTION\n", prec, " TGID ");
4362 seq_printf(m, "# | | %.*s | ||||| | |\n", prec, " | ");
4366 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
4368 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
4369 struct array_buffer *buf = iter->array_buffer;
4370 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
4371 struct tracer *type = iter->trace;
4372 unsigned long entries;
4373 unsigned long total;
4374 const char *name = type->name;
4376 get_total_entries(buf, &total, &entries);
4378 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
4380 seq_puts(m, "# -----------------------------------"
4381 "---------------------------------\n");
4382 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
4383 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
4384 nsecs_to_usecs(data->saved_latency),
4388 preempt_model_none() ? "server" :
4389 preempt_model_voluntary() ? "desktop" :
4390 preempt_model_full() ? "preempt" :
4391 preempt_model_rt() ? "preempt_rt" :
4393 /* These are reserved for later use */
4396 seq_printf(m, " #P:%d)\n", num_online_cpus());
4400 seq_puts(m, "# -----------------\n");
4401 seq_printf(m, "# | task: %.16s-%d "
4402 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
4403 data->comm, data->pid,
4404 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
4405 data->policy, data->rt_priority);
4406 seq_puts(m, "# -----------------\n");
4408 if (data->critical_start) {
4409 seq_puts(m, "# => started at: ");
4410 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
4411 trace_print_seq(m, &iter->seq);
4412 seq_puts(m, "\n# => ended at: ");
4413 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
4414 trace_print_seq(m, &iter->seq);
4415 seq_puts(m, "\n#\n");
4421 static void test_cpu_buff_start(struct trace_iterator *iter)
4423 struct trace_seq *s = &iter->seq;
4424 struct trace_array *tr = iter->tr;
4426 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
4429 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
4432 if (cpumask_available(iter->started) &&
4433 cpumask_test_cpu(iter->cpu, iter->started))
4436 if (per_cpu_ptr(iter->array_buffer->data, iter->cpu)->skipped_entries)
4439 if (cpumask_available(iter->started))
4440 cpumask_set_cpu(iter->cpu, iter->started);
4442 /* Don't print started cpu buffer for the first entry of the trace */
4444 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
4448 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
4450 struct trace_array *tr = iter->tr;
4451 struct trace_seq *s = &iter->seq;
4452 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
4453 struct trace_entry *entry;
4454 struct trace_event *event;
4458 test_cpu_buff_start(iter);
4460 event = ftrace_find_event(entry->type);
4462 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4463 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4464 trace_print_lat_context(iter);
4466 trace_print_context(iter);
4469 if (trace_seq_has_overflowed(s))
4470 return TRACE_TYPE_PARTIAL_LINE;
4473 if (tr->trace_flags & TRACE_ITER_FIELDS)
4474 return print_event_fields(iter, event);
4475 return event->funcs->trace(iter, sym_flags, event);
4478 trace_seq_printf(s, "Unknown type %d\n", entry->type);
4480 return trace_handle_return(s);
4483 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
4485 struct trace_array *tr = iter->tr;
4486 struct trace_seq *s = &iter->seq;
4487 struct trace_entry *entry;
4488 struct trace_event *event;
4492 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
4493 trace_seq_printf(s, "%d %d %llu ",
4494 entry->pid, iter->cpu, iter->ts);
4496 if (trace_seq_has_overflowed(s))
4497 return TRACE_TYPE_PARTIAL_LINE;
4499 event = ftrace_find_event(entry->type);
4501 return event->funcs->raw(iter, 0, event);
4503 trace_seq_printf(s, "%d ?\n", entry->type);
4505 return trace_handle_return(s);
4508 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
4510 struct trace_array *tr = iter->tr;
4511 struct trace_seq *s = &iter->seq;
4512 unsigned char newline = '\n';
4513 struct trace_entry *entry;
4514 struct trace_event *event;
4518 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4519 SEQ_PUT_HEX_FIELD(s, entry->pid);
4520 SEQ_PUT_HEX_FIELD(s, iter->cpu);
4521 SEQ_PUT_HEX_FIELD(s, iter->ts);
4522 if (trace_seq_has_overflowed(s))
4523 return TRACE_TYPE_PARTIAL_LINE;
4526 event = ftrace_find_event(entry->type);
4528 enum print_line_t ret = event->funcs->hex(iter, 0, event);
4529 if (ret != TRACE_TYPE_HANDLED)
4533 SEQ_PUT_FIELD(s, newline);
4535 return trace_handle_return(s);
4538 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
4540 struct trace_array *tr = iter->tr;
4541 struct trace_seq *s = &iter->seq;
4542 struct trace_entry *entry;
4543 struct trace_event *event;
4547 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4548 SEQ_PUT_FIELD(s, entry->pid);
4549 SEQ_PUT_FIELD(s, iter->cpu);
4550 SEQ_PUT_FIELD(s, iter->ts);
4551 if (trace_seq_has_overflowed(s))
4552 return TRACE_TYPE_PARTIAL_LINE;
4555 event = ftrace_find_event(entry->type);
4556 return event ? event->funcs->binary(iter, 0, event) :
4560 int trace_empty(struct trace_iterator *iter)
4562 struct ring_buffer_iter *buf_iter;
4565 /* If we are looking at one CPU buffer, only check that one */
4566 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4567 cpu = iter->cpu_file;
4568 buf_iter = trace_buffer_iter(iter, cpu);
4570 if (!ring_buffer_iter_empty(buf_iter))
4573 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4579 for_each_tracing_cpu(cpu) {
4580 buf_iter = trace_buffer_iter(iter, cpu);
4582 if (!ring_buffer_iter_empty(buf_iter))
4585 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4593 /* Called with trace_event_read_lock() held. */
4594 enum print_line_t print_trace_line(struct trace_iterator *iter)
4596 struct trace_array *tr = iter->tr;
4597 unsigned long trace_flags = tr->trace_flags;
4598 enum print_line_t ret;
4600 if (iter->lost_events) {
4601 if (iter->lost_events == (unsigned long)-1)
4602 trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n",
4605 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
4606 iter->cpu, iter->lost_events);
4607 if (trace_seq_has_overflowed(&iter->seq))
4608 return TRACE_TYPE_PARTIAL_LINE;
4611 if (iter->trace && iter->trace->print_line) {
4612 ret = iter->trace->print_line(iter);
4613 if (ret != TRACE_TYPE_UNHANDLED)
4617 if (iter->ent->type == TRACE_BPUTS &&
4618 trace_flags & TRACE_ITER_PRINTK &&
4619 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4620 return trace_print_bputs_msg_only(iter);
4622 if (iter->ent->type == TRACE_BPRINT &&
4623 trace_flags & TRACE_ITER_PRINTK &&
4624 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4625 return trace_print_bprintk_msg_only(iter);
4627 if (iter->ent->type == TRACE_PRINT &&
4628 trace_flags & TRACE_ITER_PRINTK &&
4629 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4630 return trace_print_printk_msg_only(iter);
4632 if (trace_flags & TRACE_ITER_BIN)
4633 return print_bin_fmt(iter);
4635 if (trace_flags & TRACE_ITER_HEX)
4636 return print_hex_fmt(iter);
4638 if (trace_flags & TRACE_ITER_RAW)
4639 return print_raw_fmt(iter);
4641 return print_trace_fmt(iter);
4644 void trace_latency_header(struct seq_file *m)
4646 struct trace_iterator *iter = m->private;
4647 struct trace_array *tr = iter->tr;
4649 /* print nothing if the buffers are empty */
4650 if (trace_empty(iter))
4653 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4654 print_trace_header(m, iter);
4656 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
4657 print_lat_help_header(m);
4660 void trace_default_header(struct seq_file *m)
4662 struct trace_iterator *iter = m->private;
4663 struct trace_array *tr = iter->tr;
4664 unsigned long trace_flags = tr->trace_flags;
4666 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
4669 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
4670 /* print nothing if the buffers are empty */
4671 if (trace_empty(iter))
4673 print_trace_header(m, iter);
4674 if (!(trace_flags & TRACE_ITER_VERBOSE))
4675 print_lat_help_header(m);
4677 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
4678 if (trace_flags & TRACE_ITER_IRQ_INFO)
4679 print_func_help_header_irq(iter->array_buffer,
4682 print_func_help_header(iter->array_buffer, m,
4688 static void test_ftrace_alive(struct seq_file *m)
4690 if (!ftrace_is_dead())
4692 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
4693 "# MAY BE MISSING FUNCTION EVENTS\n");
4696 #ifdef CONFIG_TRACER_MAX_TRACE
4697 static void show_snapshot_main_help(struct seq_file *m)
4699 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
4700 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4701 "# Takes a snapshot of the main buffer.\n"
4702 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
4703 "# (Doesn't have to be '2' works with any number that\n"
4704 "# is not a '0' or '1')\n");
4707 static void show_snapshot_percpu_help(struct seq_file *m)
4709 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
4710 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
4711 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4712 "# Takes a snapshot of the main buffer for this cpu.\n");
4714 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
4715 "# Must use main snapshot file to allocate.\n");
4717 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
4718 "# (Doesn't have to be '2' works with any number that\n"
4719 "# is not a '0' or '1')\n");
4722 static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
4724 if (iter->tr->allocated_snapshot)
4725 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
4727 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
4729 seq_puts(m, "# Snapshot commands:\n");
4730 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4731 show_snapshot_main_help(m);
4733 show_snapshot_percpu_help(m);
4736 /* Should never be called */
4737 static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
4740 static int s_show(struct seq_file *m, void *v)
4742 struct trace_iterator *iter = v;
4745 if (iter->ent == NULL) {
4747 seq_printf(m, "# tracer: %s\n", iter->trace->name);
4749 test_ftrace_alive(m);
4751 if (iter->snapshot && trace_empty(iter))
4752 print_snapshot_help(m, iter);
4753 else if (iter->trace && iter->trace->print_header)
4754 iter->trace->print_header(m);
4756 trace_default_header(m);
4758 } else if (iter->leftover) {
4760 * If we filled the seq_file buffer earlier, we
4761 * want to just show it now.
4763 ret = trace_print_seq(m, &iter->seq);
4765 /* ret should this time be zero, but you never know */
4766 iter->leftover = ret;
4769 print_trace_line(iter);
4770 ret = trace_print_seq(m, &iter->seq);
4772 * If we overflow the seq_file buffer, then it will
4773 * ask us for this data again at start up.
4775 * ret is 0 if seq_file write succeeded.
4778 iter->leftover = ret;
4785 * Should be used after trace_array_get(), trace_types_lock
4786 * ensures that i_cdev was already initialized.
4788 static inline int tracing_get_cpu(struct inode *inode)
4790 if (inode->i_cdev) /* See trace_create_cpu_file() */
4791 return (long)inode->i_cdev - 1;
4792 return RING_BUFFER_ALL_CPUS;
4795 static const struct seq_operations tracer_seq_ops = {
4803 * Note, as iter itself can be allocated and freed in different
4804 * ways, this function is only used to free its content, and not
4805 * the iterator itself. The only requirement to all the allocations
4806 * is that it must zero all fields (kzalloc), as freeing works with
4807 * ethier allocated content or NULL.
4809 static void free_trace_iter_content(struct trace_iterator *iter)
4811 /* The fmt is either NULL, allocated or points to static_fmt_buf */
4812 if (iter->fmt != static_fmt_buf)
4816 kfree(iter->buffer_iter);
4817 mutex_destroy(&iter->mutex);
4818 free_cpumask_var(iter->started);
4821 static struct trace_iterator *
4822 __tracing_open(struct inode *inode, struct file *file, bool snapshot)
4824 struct trace_array *tr = inode->i_private;
4825 struct trace_iterator *iter;
4828 if (tracing_disabled)
4829 return ERR_PTR(-ENODEV);
4831 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
4833 return ERR_PTR(-ENOMEM);
4835 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
4837 if (!iter->buffer_iter)
4841 * trace_find_next_entry() may need to save off iter->ent.
4842 * It will place it into the iter->temp buffer. As most
4843 * events are less than 128, allocate a buffer of that size.
4844 * If one is greater, then trace_find_next_entry() will
4845 * allocate a new buffer to adjust for the bigger iter->ent.
4846 * It's not critical if it fails to get allocated here.
4848 iter->temp = kmalloc(128, GFP_KERNEL);
4850 iter->temp_size = 128;
4853 * trace_event_printf() may need to modify given format
4854 * string to replace %p with %px so that it shows real address
4855 * instead of hash value. However, that is only for the event
4856 * tracing, other tracer may not need. Defer the allocation
4857 * until it is needed.
4862 mutex_lock(&trace_types_lock);
4863 iter->trace = tr->current_trace;
4865 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
4870 #ifdef CONFIG_TRACER_MAX_TRACE
4871 /* Currently only the top directory has a snapshot */
4872 if (tr->current_trace->print_max || snapshot)
4873 iter->array_buffer = &tr->max_buffer;
4876 iter->array_buffer = &tr->array_buffer;
4877 iter->snapshot = snapshot;
4879 iter->cpu_file = tracing_get_cpu(inode);
4880 mutex_init(&iter->mutex);
4882 /* Notify the tracer early; before we stop tracing. */
4883 if (iter->trace->open)
4884 iter->trace->open(iter);
4886 /* Annotate start of buffers if we had overruns */
4887 if (ring_buffer_overruns(iter->array_buffer->buffer))
4888 iter->iter_flags |= TRACE_FILE_ANNOTATE;
4890 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4891 if (trace_clocks[tr->clock_id].in_ns)
4892 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4895 * If pause-on-trace is enabled, then stop the trace while
4896 * dumping, unless this is the "snapshot" file
4898 if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
4899 tracing_stop_tr(tr);
4901 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
4902 for_each_tracing_cpu(cpu) {
4903 iter->buffer_iter[cpu] =
4904 ring_buffer_read_prepare(iter->array_buffer->buffer,
4907 ring_buffer_read_prepare_sync();
4908 for_each_tracing_cpu(cpu) {
4909 ring_buffer_read_start(iter->buffer_iter[cpu]);
4910 tracing_iter_reset(iter, cpu);
4913 cpu = iter->cpu_file;
4914 iter->buffer_iter[cpu] =
4915 ring_buffer_read_prepare(iter->array_buffer->buffer,
4917 ring_buffer_read_prepare_sync();
4918 ring_buffer_read_start(iter->buffer_iter[cpu]);
4919 tracing_iter_reset(iter, cpu);
4922 mutex_unlock(&trace_types_lock);
4927 mutex_unlock(&trace_types_lock);
4928 free_trace_iter_content(iter);
4930 seq_release_private(inode, file);
4931 return ERR_PTR(-ENOMEM);
4934 int tracing_open_generic(struct inode *inode, struct file *filp)
4938 ret = tracing_check_open_get_tr(NULL);
4942 filp->private_data = inode->i_private;
4946 bool tracing_is_disabled(void)
4948 return (tracing_disabled) ? true: false;
4952 * Open and update trace_array ref count.
4953 * Must have the current trace_array passed to it.
4955 int tracing_open_generic_tr(struct inode *inode, struct file *filp)
4957 struct trace_array *tr = inode->i_private;
4960 ret = tracing_check_open_get_tr(tr);
4964 filp->private_data = inode->i_private;
4969 static int tracing_mark_open(struct inode *inode, struct file *filp)
4971 stream_open(inode, filp);
4972 return tracing_open_generic_tr(inode, filp);
4975 static int tracing_release(struct inode *inode, struct file *file)
4977 struct trace_array *tr = inode->i_private;
4978 struct seq_file *m = file->private_data;
4979 struct trace_iterator *iter;
4982 if (!(file->f_mode & FMODE_READ)) {
4983 trace_array_put(tr);
4987 /* Writes do not use seq_file */
4989 mutex_lock(&trace_types_lock);
4991 for_each_tracing_cpu(cpu) {
4992 if (iter->buffer_iter[cpu])
4993 ring_buffer_read_finish(iter->buffer_iter[cpu]);
4996 if (iter->trace && iter->trace->close)
4997 iter->trace->close(iter);
4999 if (!iter->snapshot && tr->stop_count)
5000 /* reenable tracing if it was previously enabled */
5001 tracing_start_tr(tr);
5003 __trace_array_put(tr);
5005 mutex_unlock(&trace_types_lock);
5007 free_trace_iter_content(iter);
5008 seq_release_private(inode, file);
5013 static int tracing_release_generic_tr(struct inode *inode, struct file *file)
5015 struct trace_array *tr = inode->i_private;
5017 trace_array_put(tr);
5021 static int tracing_single_release_tr(struct inode *inode, struct file *file)
5023 struct trace_array *tr = inode->i_private;
5025 trace_array_put(tr);
5027 return single_release(inode, file);
5030 static int tracing_open(struct inode *inode, struct file *file)
5032 struct trace_array *tr = inode->i_private;
5033 struct trace_iterator *iter;
5036 ret = tracing_check_open_get_tr(tr);
5040 /* If this file was open for write, then erase contents */
5041 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
5042 int cpu = tracing_get_cpu(inode);
5043 struct array_buffer *trace_buf = &tr->array_buffer;
5045 #ifdef CONFIG_TRACER_MAX_TRACE
5046 if (tr->current_trace->print_max)
5047 trace_buf = &tr->max_buffer;
5050 if (cpu == RING_BUFFER_ALL_CPUS)
5051 tracing_reset_online_cpus(trace_buf);
5053 tracing_reset_cpu(trace_buf, cpu);
5056 if (file->f_mode & FMODE_READ) {
5057 iter = __tracing_open(inode, file, false);
5059 ret = PTR_ERR(iter);
5060 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
5061 iter->iter_flags |= TRACE_FILE_LAT_FMT;
5065 trace_array_put(tr);
5071 * Some tracers are not suitable for instance buffers.
5072 * A tracer is always available for the global array (toplevel)
5073 * or if it explicitly states that it is.
5076 trace_ok_for_array(struct tracer *t, struct trace_array *tr)
5078 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
5081 /* Find the next tracer that this trace array may use */
5082 static struct tracer *
5083 get_tracer_for_array(struct trace_array *tr, struct tracer *t)
5085 while (t && !trace_ok_for_array(t, tr))
5092 t_next(struct seq_file *m, void *v, loff_t *pos)
5094 struct trace_array *tr = m->private;
5095 struct tracer *t = v;
5100 t = get_tracer_for_array(tr, t->next);
5105 static void *t_start(struct seq_file *m, loff_t *pos)
5107 struct trace_array *tr = m->private;
5111 mutex_lock(&trace_types_lock);
5113 t = get_tracer_for_array(tr, trace_types);
5114 for (; t && l < *pos; t = t_next(m, t, &l))
5120 static void t_stop(struct seq_file *m, void *p)
5122 mutex_unlock(&trace_types_lock);
5125 static int t_show(struct seq_file *m, void *v)
5127 struct tracer *t = v;
5132 seq_puts(m, t->name);
5141 static const struct seq_operations show_traces_seq_ops = {
5148 static int show_traces_open(struct inode *inode, struct file *file)
5150 struct trace_array *tr = inode->i_private;
5154 ret = tracing_check_open_get_tr(tr);
5158 ret = seq_open(file, &show_traces_seq_ops);
5160 trace_array_put(tr);
5164 m = file->private_data;
5170 static int show_traces_release(struct inode *inode, struct file *file)
5172 struct trace_array *tr = inode->i_private;
5174 trace_array_put(tr);
5175 return seq_release(inode, file);
5179 tracing_write_stub(struct file *filp, const char __user *ubuf,
5180 size_t count, loff_t *ppos)
5185 loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
5189 if (file->f_mode & FMODE_READ)
5190 ret = seq_lseek(file, offset, whence);
5192 file->f_pos = ret = 0;
5197 static const struct file_operations tracing_fops = {
5198 .open = tracing_open,
5200 .read_iter = seq_read_iter,
5201 .splice_read = copy_splice_read,
5202 .write = tracing_write_stub,
5203 .llseek = tracing_lseek,
5204 .release = tracing_release,
5207 static const struct file_operations show_traces_fops = {
5208 .open = show_traces_open,
5210 .llseek = seq_lseek,
5211 .release = show_traces_release,
5215 tracing_cpumask_read(struct file *filp, char __user *ubuf,
5216 size_t count, loff_t *ppos)
5218 struct trace_array *tr = file_inode(filp)->i_private;
5222 len = snprintf(NULL, 0, "%*pb\n",
5223 cpumask_pr_args(tr->tracing_cpumask)) + 1;
5224 mask_str = kmalloc(len, GFP_KERNEL);
5228 len = snprintf(mask_str, len, "%*pb\n",
5229 cpumask_pr_args(tr->tracing_cpumask));
5234 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
5242 int tracing_set_cpumask(struct trace_array *tr,
5243 cpumask_var_t tracing_cpumask_new)
5250 local_irq_disable();
5251 arch_spin_lock(&tr->max_lock);
5252 for_each_tracing_cpu(cpu) {
5254 * Increase/decrease the disabled counter if we are
5255 * about to flip a bit in the cpumask:
5257 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5258 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5259 atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5260 ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
5262 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5263 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5264 atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5265 ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
5268 arch_spin_unlock(&tr->max_lock);
5271 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
5277 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
5278 size_t count, loff_t *ppos)
5280 struct trace_array *tr = file_inode(filp)->i_private;
5281 cpumask_var_t tracing_cpumask_new;
5284 if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
5287 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
5291 err = tracing_set_cpumask(tr, tracing_cpumask_new);
5295 free_cpumask_var(tracing_cpumask_new);
5300 free_cpumask_var(tracing_cpumask_new);
5305 static const struct file_operations tracing_cpumask_fops = {
5306 .open = tracing_open_generic_tr,
5307 .read = tracing_cpumask_read,
5308 .write = tracing_cpumask_write,
5309 .release = tracing_release_generic_tr,
5310 .llseek = generic_file_llseek,
5313 static int tracing_trace_options_show(struct seq_file *m, void *v)
5315 struct tracer_opt *trace_opts;
5316 struct trace_array *tr = m->private;
5320 mutex_lock(&trace_types_lock);
5321 tracer_flags = tr->current_trace->flags->val;
5322 trace_opts = tr->current_trace->flags->opts;
5324 for (i = 0; trace_options[i]; i++) {
5325 if (tr->trace_flags & (1 << i))
5326 seq_printf(m, "%s\n", trace_options[i]);
5328 seq_printf(m, "no%s\n", trace_options[i]);
5331 for (i = 0; trace_opts[i].name; i++) {
5332 if (tracer_flags & trace_opts[i].bit)
5333 seq_printf(m, "%s\n", trace_opts[i].name);
5335 seq_printf(m, "no%s\n", trace_opts[i].name);
5337 mutex_unlock(&trace_types_lock);
5342 static int __set_tracer_option(struct trace_array *tr,
5343 struct tracer_flags *tracer_flags,
5344 struct tracer_opt *opts, int neg)
5346 struct tracer *trace = tracer_flags->trace;
5349 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
5354 tracer_flags->val &= ~opts->bit;
5356 tracer_flags->val |= opts->bit;
5360 /* Try to assign a tracer specific option */
5361 static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
5363 struct tracer *trace = tr->current_trace;
5364 struct tracer_flags *tracer_flags = trace->flags;
5365 struct tracer_opt *opts = NULL;
5368 for (i = 0; tracer_flags->opts[i].name; i++) {
5369 opts = &tracer_flags->opts[i];
5371 if (strcmp(cmp, opts->name) == 0)
5372 return __set_tracer_option(tr, trace->flags, opts, neg);
5378 /* Some tracers require overwrite to stay enabled */
5379 int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
5381 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
5387 int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
5391 if ((mask == TRACE_ITER_RECORD_TGID) ||
5392 (mask == TRACE_ITER_RECORD_CMD))
5393 lockdep_assert_held(&event_mutex);
5395 /* do nothing if flag is already set */
5396 if (!!(tr->trace_flags & mask) == !!enabled)
5399 /* Give the tracer a chance to approve the change */
5400 if (tr->current_trace->flag_changed)
5401 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
5405 tr->trace_flags |= mask;
5407 tr->trace_flags &= ~mask;
5409 if (mask == TRACE_ITER_RECORD_CMD)
5410 trace_event_enable_cmd_record(enabled);
5412 if (mask == TRACE_ITER_RECORD_TGID) {
5414 tgid_map_max = pid_max;
5415 map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
5419 * Pairs with smp_load_acquire() in
5420 * trace_find_tgid_ptr() to ensure that if it observes
5421 * the tgid_map we just allocated then it also observes
5422 * the corresponding tgid_map_max value.
5424 smp_store_release(&tgid_map, map);
5427 tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
5431 trace_event_enable_tgid_record(enabled);
5434 if (mask == TRACE_ITER_EVENT_FORK)
5435 trace_event_follow_fork(tr, enabled);
5437 if (mask == TRACE_ITER_FUNC_FORK)
5438 ftrace_pid_follow_fork(tr, enabled);
5440 if (mask == TRACE_ITER_OVERWRITE) {
5441 ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled);
5442 #ifdef CONFIG_TRACER_MAX_TRACE
5443 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
5447 if (mask == TRACE_ITER_PRINTK) {
5448 trace_printk_start_stop_comm(enabled);
5449 trace_printk_control(enabled);
5455 int trace_set_options(struct trace_array *tr, char *option)
5460 size_t orig_len = strlen(option);
5463 cmp = strstrip(option);
5465 len = str_has_prefix(cmp, "no");
5471 mutex_lock(&event_mutex);
5472 mutex_lock(&trace_types_lock);
5474 ret = match_string(trace_options, -1, cmp);
5475 /* If no option could be set, test the specific tracer options */
5477 ret = set_tracer_option(tr, cmp, neg);
5479 ret = set_tracer_flag(tr, 1 << ret, !neg);
5481 mutex_unlock(&trace_types_lock);
5482 mutex_unlock(&event_mutex);
5485 * If the first trailing whitespace is replaced with '\0' by strstrip,
5486 * turn it back into a space.
5488 if (orig_len > strlen(option))
5489 option[strlen(option)] = ' ';
5494 static void __init apply_trace_boot_options(void)
5496 char *buf = trace_boot_options_buf;
5500 option = strsep(&buf, ",");
5506 trace_set_options(&global_trace, option);
5508 /* Put back the comma to allow this to be called again */
5515 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
5516 size_t cnt, loff_t *ppos)
5518 struct seq_file *m = filp->private_data;
5519 struct trace_array *tr = m->private;
5523 if (cnt >= sizeof(buf))
5526 if (copy_from_user(buf, ubuf, cnt))
5531 ret = trace_set_options(tr, buf);
5540 static int tracing_trace_options_open(struct inode *inode, struct file *file)
5542 struct trace_array *tr = inode->i_private;
5545 ret = tracing_check_open_get_tr(tr);
5549 ret = single_open(file, tracing_trace_options_show, inode->i_private);
5551 trace_array_put(tr);
5556 static const struct file_operations tracing_iter_fops = {
5557 .open = tracing_trace_options_open,
5559 .llseek = seq_lseek,
5560 .release = tracing_single_release_tr,
5561 .write = tracing_trace_options_write,
5564 static const char readme_msg[] =
5565 "tracing mini-HOWTO:\n\n"
5566 "# echo 0 > tracing_on : quick way to disable tracing\n"
5567 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
5568 " Important files:\n"
5569 " trace\t\t\t- The static contents of the buffer\n"
5570 "\t\t\t To clear the buffer write into this file: echo > trace\n"
5571 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
5572 " current_tracer\t- function and latency tracers\n"
5573 " available_tracers\t- list of configured tracers for current_tracer\n"
5574 " error_log\t- error log for failed commands (that support it)\n"
5575 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
5576 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
5577 " trace_clock\t\t- change the clock used to order events\n"
5578 " local: Per cpu clock but may not be synced across CPUs\n"
5579 " global: Synced across CPUs but slows tracing down.\n"
5580 " counter: Not a clock, but just an increment\n"
5581 " uptime: Jiffy counter from time of boot\n"
5582 " perf: Same clock that perf events use\n"
5583 #ifdef CONFIG_X86_64
5584 " x86-tsc: TSC cycle counter\n"
5586 "\n timestamp_mode\t- view the mode used to timestamp events\n"
5587 " delta: Delta difference against a buffer-wide timestamp\n"
5588 " absolute: Absolute (standalone) timestamp\n"
5589 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
5590 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
5591 " tracing_cpumask\t- Limit which CPUs to trace\n"
5592 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
5593 "\t\t\t Remove sub-buffer with rmdir\n"
5594 " trace_options\t\t- Set format or modify how tracing happens\n"
5595 "\t\t\t Disable an option by prefixing 'no' to the\n"
5596 "\t\t\t option name\n"
5597 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
5598 #ifdef CONFIG_DYNAMIC_FTRACE
5599 "\n available_filter_functions - list of functions that can be filtered on\n"
5600 " set_ftrace_filter\t- echo function name in here to only trace these\n"
5601 "\t\t\t functions\n"
5602 "\t accepts: func_full_name or glob-matching-pattern\n"
5603 "\t modules: Can select a group via module\n"
5604 "\t Format: :mod:<module-name>\n"
5605 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
5606 "\t triggers: a command to perform when function is hit\n"
5607 "\t Format: <function>:<trigger>[:count]\n"
5608 "\t trigger: traceon, traceoff\n"
5609 "\t\t enable_event:<system>:<event>\n"
5610 "\t\t disable_event:<system>:<event>\n"
5611 #ifdef CONFIG_STACKTRACE
5614 #ifdef CONFIG_TRACER_SNAPSHOT
5619 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
5620 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
5621 "\t The first one will disable tracing every time do_fault is hit\n"
5622 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
5623 "\t The first time do trap is hit and it disables tracing, the\n"
5624 "\t counter will decrement to 2. If tracing is already disabled,\n"
5625 "\t the counter will not decrement. It only decrements when the\n"
5626 "\t trigger did work\n"
5627 "\t To remove trigger without count:\n"
5628 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
5629 "\t To remove trigger with a count:\n"
5630 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
5631 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
5632 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
5633 "\t modules: Can select a group via module command :mod:\n"
5634 "\t Does not accept triggers\n"
5635 #endif /* CONFIG_DYNAMIC_FTRACE */
5636 #ifdef CONFIG_FUNCTION_TRACER
5637 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
5639 " set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n"
5642 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5643 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
5644 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
5645 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
5647 #ifdef CONFIG_TRACER_SNAPSHOT
5648 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
5649 "\t\t\t snapshot buffer. Read the contents for more\n"
5650 "\t\t\t information\n"
5652 #ifdef CONFIG_STACK_TRACER
5653 " stack_trace\t\t- Shows the max stack trace when active\n"
5654 " stack_max_size\t- Shows current max stack size that was traced\n"
5655 "\t\t\t Write into this file to reset the max size (trigger a\n"
5656 "\t\t\t new trace)\n"
5657 #ifdef CONFIG_DYNAMIC_FTRACE
5658 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
5661 #endif /* CONFIG_STACK_TRACER */
5662 #ifdef CONFIG_DYNAMIC_EVENTS
5663 " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
5664 "\t\t\t Write into this file to define/undefine new trace events.\n"
5666 #ifdef CONFIG_KPROBE_EVENTS
5667 " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
5668 "\t\t\t Write into this file to define/undefine new trace events.\n"
5670 #ifdef CONFIG_UPROBE_EVENTS
5671 " uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
5672 "\t\t\t Write into this file to define/undefine new trace events.\n"
5674 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) || \
5675 defined(CONFIG_FPROBE_EVENTS)
5676 "\t accepts: event-definitions (one definition per line)\n"
5677 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
5678 "\t Format: p[:[<group>/][<event>]] <place> [<args>]\n"
5679 "\t r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
5681 #ifdef CONFIG_FPROBE_EVENTS
5682 "\t f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
5683 "\t t[:[<group>/][<event>]] <tracepoint> [<args>]\n"
5685 #ifdef CONFIG_HIST_TRIGGERS
5686 "\t s:[synthetic/]<event> <field> [<field>]\n"
5688 "\t e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>] [if <filter>]\n"
5689 "\t -:[<group>/][<event>]\n"
5690 #ifdef CONFIG_KPROBE_EVENTS
5691 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
5692 "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"
5694 #ifdef CONFIG_UPROBE_EVENTS
5695 " place (uprobe): <path>:<offset>[%return][(ref_ctr_offset)]\n"
5697 "\t args: <name>=fetcharg[:type]\n"
5698 "\t fetcharg: (%<register>|$<efield>), @<address>, @<symbol>[+|-<offset>],\n"
5699 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
5700 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
5701 "\t $stack<index>, $stack, $retval, $comm, $arg<N>, <argname>\n"
5703 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5706 "\t $stack<index>, $stack, $retval, $comm,\n"
5708 "\t +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
5709 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, char, string, symbol,\n"
5710 "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
5711 "\t symstr, <type>\\[<array-size>\\]\n"
5712 #ifdef CONFIG_HIST_TRIGGERS
5713 "\t field: <stype> <name>;\n"
5714 "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
5715 "\t [unsigned] char/int/long\n"
5717 "\t efield: For event probes ('e' types), the field is on of the fields\n"
5718 "\t of the <attached-group>/<attached-event>.\n"
5720 " events/\t\t- Directory containing all trace event subsystems:\n"
5721 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
5722 " events/<system>/\t- Directory containing all trace events for <system>:\n"
5723 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
5725 " filter\t\t- If set, only events passing filter are traced\n"
5726 " events/<system>/<event>/\t- Directory containing control files for\n"
5728 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
5729 " filter\t\t- If set, only events passing filter are traced\n"
5730 " trigger\t\t- If set, a command to perform when event is hit\n"
5731 "\t Format: <trigger>[:count][if <filter>]\n"
5732 "\t trigger: traceon, traceoff\n"
5733 "\t enable_event:<system>:<event>\n"
5734 "\t disable_event:<system>:<event>\n"
5735 #ifdef CONFIG_HIST_TRIGGERS
5736 "\t enable_hist:<system>:<event>\n"
5737 "\t disable_hist:<system>:<event>\n"
5739 #ifdef CONFIG_STACKTRACE
5742 #ifdef CONFIG_TRACER_SNAPSHOT
5745 #ifdef CONFIG_HIST_TRIGGERS
5746 "\t\t hist (see below)\n"
5748 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
5749 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
5750 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
5751 "\t events/block/block_unplug/trigger\n"
5752 "\t The first disables tracing every time block_unplug is hit.\n"
5753 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
5754 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
5755 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
5756 "\t Like function triggers, the counter is only decremented if it\n"
5757 "\t enabled or disabled tracing.\n"
5758 "\t To remove a trigger without a count:\n"
5759 "\t echo '!<trigger> > <system>/<event>/trigger\n"
5760 "\t To remove a trigger with a count:\n"
5761 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
5762 "\t Filters can be ignored when removing a trigger.\n"
5763 #ifdef CONFIG_HIST_TRIGGERS
5764 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
5765 "\t Format: hist:keys=<field1[,field2,...]>\n"
5766 "\t [:<var1>=<field|var_ref|numeric_literal>[,<var2>=...]]\n"
5767 "\t [:values=<field1[,field2,...]>]\n"
5768 "\t [:sort=<field1[,field2,...]>]\n"
5769 "\t [:size=#entries]\n"
5770 "\t [:pause][:continue][:clear]\n"
5771 "\t [:name=histname1]\n"
5772 "\t [:nohitcount]\n"
5773 "\t [:<handler>.<action>]\n"
5774 "\t [if <filter>]\n\n"
5775 "\t Note, special fields can be used as well:\n"
5776 "\t common_timestamp - to record current timestamp\n"
5777 "\t common_cpu - to record the CPU the event happened on\n"
5779 "\t A hist trigger variable can be:\n"
5780 "\t - a reference to a field e.g. x=current_timestamp,\n"
5781 "\t - a reference to another variable e.g. y=$x,\n"
5782 "\t - a numeric literal: e.g. ms_per_sec=1000,\n"
5783 "\t - an arithmetic expression: e.g. time_secs=current_timestamp/1000\n"
5785 "\t hist trigger arithmetic expressions support addition(+), subtraction(-),\n"
5786 "\t multiplication(*) and division(/) operators. An operand can be either a\n"
5787 "\t variable reference, field or numeric literal.\n"
5789 "\t When a matching event is hit, an entry is added to a hash\n"
5790 "\t table using the key(s) and value(s) named, and the value of a\n"
5791 "\t sum called 'hitcount' is incremented. Keys and values\n"
5792 "\t correspond to fields in the event's format description. Keys\n"
5793 "\t can be any field, or the special string 'common_stacktrace'.\n"
5794 "\t Compound keys consisting of up to two fields can be specified\n"
5795 "\t by the 'keys' keyword. Values must correspond to numeric\n"
5796 "\t fields. Sort keys consisting of up to two fields can be\n"
5797 "\t specified using the 'sort' keyword. The sort direction can\n"
5798 "\t be modified by appending '.descending' or '.ascending' to a\n"
5799 "\t sort field. The 'size' parameter can be used to specify more\n"
5800 "\t or fewer than the default 2048 entries for the hashtable size.\n"
5801 "\t If a hist trigger is given a name using the 'name' parameter,\n"
5802 "\t its histogram data will be shared with other triggers of the\n"
5803 "\t same name, and trigger hits will update this common data.\n\n"
5804 "\t Reading the 'hist' file for the event will dump the hash\n"
5805 "\t table in its entirety to stdout. If there are multiple hist\n"
5806 "\t triggers attached to an event, there will be a table for each\n"
5807 "\t trigger in the output. The table displayed for a named\n"
5808 "\t trigger will be the same as any other instance having the\n"
5809 "\t same name. The default format used to display a given field\n"
5810 "\t can be modified by appending any of the following modifiers\n"
5811 "\t to the field name, as applicable:\n\n"
5812 "\t .hex display a number as a hex value\n"
5813 "\t .sym display an address as a symbol\n"
5814 "\t .sym-offset display an address as a symbol and offset\n"
5815 "\t .execname display a common_pid as a program name\n"
5816 "\t .syscall display a syscall id as a syscall name\n"
5817 "\t .log2 display log2 value rather than raw number\n"
5818 "\t .buckets=size display values in groups of size rather than raw number\n"
5819 "\t .usecs display a common_timestamp in microseconds\n"
5820 "\t .percent display a number of percentage value\n"
5821 "\t .graph display a bar-graph of a value\n\n"
5822 "\t The 'pause' parameter can be used to pause an existing hist\n"
5823 "\t trigger or to start a hist trigger but not log any events\n"
5824 "\t until told to do so. 'continue' can be used to start or\n"
5825 "\t restart a paused hist trigger.\n\n"
5826 "\t The 'clear' parameter will clear the contents of a running\n"
5827 "\t hist trigger and leave its current paused/active state\n"
5829 "\t The 'nohitcount' (or NOHC) parameter will suppress display of\n"
5830 "\t raw hitcount in the histogram.\n\n"
5831 "\t The enable_hist and disable_hist triggers can be used to\n"
5832 "\t have one event conditionally start and stop another event's\n"
5833 "\t already-attached hist trigger. The syntax is analogous to\n"
5834 "\t the enable_event and disable_event triggers.\n\n"
5835 "\t Hist trigger handlers and actions are executed whenever a\n"
5836 "\t a histogram entry is added or updated. They take the form:\n\n"
5837 "\t <handler>.<action>\n\n"
5838 "\t The available handlers are:\n\n"
5839 "\t onmatch(matching.event) - invoke on addition or update\n"
5840 "\t onmax(var) - invoke if var exceeds current max\n"
5841 "\t onchange(var) - invoke action if var changes\n\n"
5842 "\t The available actions are:\n\n"
5843 "\t trace(<synthetic_event>,param list) - generate synthetic event\n"
5844 "\t save(field,...) - save current event fields\n"
5845 #ifdef CONFIG_TRACER_SNAPSHOT
5846 "\t snapshot() - snapshot the trace buffer\n\n"
5848 #ifdef CONFIG_SYNTH_EVENTS
5849 " events/synthetic_events\t- Create/append/remove/show synthetic events\n"
5850 "\t Write into this file to define/undefine new synthetic events.\n"
5851 "\t example: echo 'myevent u64 lat; char name[]; long[] stack' >> synthetic_events\n"
5857 tracing_readme_read(struct file *filp, char __user *ubuf,
5858 size_t cnt, loff_t *ppos)
5860 return simple_read_from_buffer(ubuf, cnt, ppos,
5861 readme_msg, strlen(readme_msg));
5864 static const struct file_operations tracing_readme_fops = {
5865 .open = tracing_open_generic,
5866 .read = tracing_readme_read,
5867 .llseek = generic_file_llseek,
5870 static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
5874 return trace_find_tgid_ptr(pid);
5877 static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
5881 return trace_find_tgid_ptr(pid);
5884 static void saved_tgids_stop(struct seq_file *m, void *v)
5888 static int saved_tgids_show(struct seq_file *m, void *v)
5890 int *entry = (int *)v;
5891 int pid = entry - tgid_map;
5897 seq_printf(m, "%d %d\n", pid, tgid);
5901 static const struct seq_operations tracing_saved_tgids_seq_ops = {
5902 .start = saved_tgids_start,
5903 .stop = saved_tgids_stop,
5904 .next = saved_tgids_next,
5905 .show = saved_tgids_show,
5908 static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
5912 ret = tracing_check_open_get_tr(NULL);
5916 return seq_open(filp, &tracing_saved_tgids_seq_ops);
5920 static const struct file_operations tracing_saved_tgids_fops = {
5921 .open = tracing_saved_tgids_open,
5923 .llseek = seq_lseek,
5924 .release = seq_release,
5927 static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
5929 unsigned int *ptr = v;
5931 if (*pos || m->count)
5936 for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
5938 if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
5947 static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
5953 arch_spin_lock(&trace_cmdline_lock);
5955 v = &savedcmd->map_cmdline_to_pid[0];
5957 v = saved_cmdlines_next(m, v, &l);
5965 static void saved_cmdlines_stop(struct seq_file *m, void *v)
5967 arch_spin_unlock(&trace_cmdline_lock);
5971 static int saved_cmdlines_show(struct seq_file *m, void *v)
5973 char buf[TASK_COMM_LEN];
5974 unsigned int *pid = v;
5976 __trace_find_cmdline(*pid, buf);
5977 seq_printf(m, "%d %s\n", *pid, buf);
5981 static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
5982 .start = saved_cmdlines_start,
5983 .next = saved_cmdlines_next,
5984 .stop = saved_cmdlines_stop,
5985 .show = saved_cmdlines_show,
5988 static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
5992 ret = tracing_check_open_get_tr(NULL);
5996 return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
5999 static const struct file_operations tracing_saved_cmdlines_fops = {
6000 .open = tracing_saved_cmdlines_open,
6002 .llseek = seq_lseek,
6003 .release = seq_release,
6007 tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
6008 size_t cnt, loff_t *ppos)
6014 arch_spin_lock(&trace_cmdline_lock);
6015 r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
6016 arch_spin_unlock(&trace_cmdline_lock);
6019 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6022 static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
6024 kfree(s->saved_cmdlines);
6025 kfree(s->map_cmdline_to_pid);
6029 static int tracing_resize_saved_cmdlines(unsigned int val)
6031 struct saved_cmdlines_buffer *s, *savedcmd_temp;
6033 s = kmalloc(sizeof(*s), GFP_KERNEL);
6037 if (allocate_cmdlines_buffer(val, s) < 0) {
6043 arch_spin_lock(&trace_cmdline_lock);
6044 savedcmd_temp = savedcmd;
6046 arch_spin_unlock(&trace_cmdline_lock);
6048 free_saved_cmdlines_buffer(savedcmd_temp);
6054 tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
6055 size_t cnt, loff_t *ppos)
6060 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6064 /* must have at least 1 entry or less than PID_MAX_DEFAULT */
6065 if (!val || val > PID_MAX_DEFAULT)
6068 ret = tracing_resize_saved_cmdlines((unsigned int)val);
6077 static const struct file_operations tracing_saved_cmdlines_size_fops = {
6078 .open = tracing_open_generic,
6079 .read = tracing_saved_cmdlines_size_read,
6080 .write = tracing_saved_cmdlines_size_write,
6083 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
6084 static union trace_eval_map_item *
6085 update_eval_map(union trace_eval_map_item *ptr)
6087 if (!ptr->map.eval_string) {
6088 if (ptr->tail.next) {
6089 ptr = ptr->tail.next;
6090 /* Set ptr to the next real item (skip head) */
6098 static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
6100 union trace_eval_map_item *ptr = v;
6103 * Paranoid! If ptr points to end, we don't want to increment past it.
6104 * This really should never happen.
6107 ptr = update_eval_map(ptr);
6108 if (WARN_ON_ONCE(!ptr))
6112 ptr = update_eval_map(ptr);
6117 static void *eval_map_start(struct seq_file *m, loff_t *pos)
6119 union trace_eval_map_item *v;
6122 mutex_lock(&trace_eval_mutex);
6124 v = trace_eval_maps;
6128 while (v && l < *pos) {
6129 v = eval_map_next(m, v, &l);
6135 static void eval_map_stop(struct seq_file *m, void *v)
6137 mutex_unlock(&trace_eval_mutex);
6140 static int eval_map_show(struct seq_file *m, void *v)
6142 union trace_eval_map_item *ptr = v;
6144 seq_printf(m, "%s %ld (%s)\n",
6145 ptr->map.eval_string, ptr->map.eval_value,
6151 static const struct seq_operations tracing_eval_map_seq_ops = {
6152 .start = eval_map_start,
6153 .next = eval_map_next,
6154 .stop = eval_map_stop,
6155 .show = eval_map_show,
6158 static int tracing_eval_map_open(struct inode *inode, struct file *filp)
6162 ret = tracing_check_open_get_tr(NULL);
6166 return seq_open(filp, &tracing_eval_map_seq_ops);
6169 static const struct file_operations tracing_eval_map_fops = {
6170 .open = tracing_eval_map_open,
6172 .llseek = seq_lseek,
6173 .release = seq_release,
6176 static inline union trace_eval_map_item *
6177 trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
6179 /* Return tail of array given the head */
6180 return ptr + ptr->head.length + 1;
6184 trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
6187 struct trace_eval_map **stop;
6188 struct trace_eval_map **map;
6189 union trace_eval_map_item *map_array;
6190 union trace_eval_map_item *ptr;
6195 * The trace_eval_maps contains the map plus a head and tail item,
6196 * where the head holds the module and length of array, and the
6197 * tail holds a pointer to the next list.
6199 map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
6201 pr_warn("Unable to allocate trace eval mapping\n");
6205 mutex_lock(&trace_eval_mutex);
6207 if (!trace_eval_maps)
6208 trace_eval_maps = map_array;
6210 ptr = trace_eval_maps;
6212 ptr = trace_eval_jmp_to_tail(ptr);
6213 if (!ptr->tail.next)
6215 ptr = ptr->tail.next;
6218 ptr->tail.next = map_array;
6220 map_array->head.mod = mod;
6221 map_array->head.length = len;
6224 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
6225 map_array->map = **map;
6228 memset(map_array, 0, sizeof(*map_array));
6230 mutex_unlock(&trace_eval_mutex);
6233 static void trace_create_eval_file(struct dentry *d_tracer)
6235 trace_create_file("eval_map", TRACE_MODE_READ, d_tracer,
6236 NULL, &tracing_eval_map_fops);
6239 #else /* CONFIG_TRACE_EVAL_MAP_FILE */
6240 static inline void trace_create_eval_file(struct dentry *d_tracer) { }
6241 static inline void trace_insert_eval_map_file(struct module *mod,
6242 struct trace_eval_map **start, int len) { }
6243 #endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
6245 static void trace_insert_eval_map(struct module *mod,
6246 struct trace_eval_map **start, int len)
6248 struct trace_eval_map **map;
6255 trace_event_eval_update(map, len);
6257 trace_insert_eval_map_file(mod, start, len);
6261 tracing_set_trace_read(struct file *filp, char __user *ubuf,
6262 size_t cnt, loff_t *ppos)
6264 struct trace_array *tr = filp->private_data;
6265 char buf[MAX_TRACER_SIZE+2];
6268 mutex_lock(&trace_types_lock);
6269 r = sprintf(buf, "%s\n", tr->current_trace->name);
6270 mutex_unlock(&trace_types_lock);
6272 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6275 int tracer_init(struct tracer *t, struct trace_array *tr)
6277 tracing_reset_online_cpus(&tr->array_buffer);
6281 static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
6285 for_each_tracing_cpu(cpu)
6286 per_cpu_ptr(buf->data, cpu)->entries = val;
6289 static void update_buffer_entries(struct array_buffer *buf, int cpu)
6291 if (cpu == RING_BUFFER_ALL_CPUS) {
6292 set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0));
6294 per_cpu_ptr(buf->data, cpu)->entries = ring_buffer_size(buf->buffer, cpu);
6298 #ifdef CONFIG_TRACER_MAX_TRACE
6299 /* resize @tr's buffer to the size of @size_tr's entries */
6300 static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
6301 struct array_buffer *size_buf, int cpu_id)
6305 if (cpu_id == RING_BUFFER_ALL_CPUS) {
6306 for_each_tracing_cpu(cpu) {
6307 ret = ring_buffer_resize(trace_buf->buffer,
6308 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
6311 per_cpu_ptr(trace_buf->data, cpu)->entries =
6312 per_cpu_ptr(size_buf->data, cpu)->entries;
6315 ret = ring_buffer_resize(trace_buf->buffer,
6316 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
6318 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
6319 per_cpu_ptr(size_buf->data, cpu_id)->entries;
6324 #endif /* CONFIG_TRACER_MAX_TRACE */
6326 static int __tracing_resize_ring_buffer(struct trace_array *tr,
6327 unsigned long size, int cpu)
6332 * If kernel or user changes the size of the ring buffer
6333 * we use the size that was given, and we can forget about
6334 * expanding it later.
6336 ring_buffer_expanded = true;
6338 /* May be called before buffers are initialized */
6339 if (!tr->array_buffer.buffer)
6342 ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu);
6346 #ifdef CONFIG_TRACER_MAX_TRACE
6347 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
6348 !tr->current_trace->use_max_tr)
6351 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
6353 int r = resize_buffer_duplicate_size(&tr->array_buffer,
6354 &tr->array_buffer, cpu);
6357 * AARGH! We are left with different
6358 * size max buffer!!!!
6359 * The max buffer is our "snapshot" buffer.
6360 * When a tracer needs a snapshot (one of the
6361 * latency tracers), it swaps the max buffer
6362 * with the saved snap shot. We succeeded to
6363 * update the size of the main buffer, but failed to
6364 * update the size of the max buffer. But when we tried
6365 * to reset the main buffer to the original size, we
6366 * failed there too. This is very unlikely to
6367 * happen, but if it does, warn and kill all
6371 tracing_disabled = 1;
6376 update_buffer_entries(&tr->max_buffer, cpu);
6379 #endif /* CONFIG_TRACER_MAX_TRACE */
6381 update_buffer_entries(&tr->array_buffer, cpu);
6386 ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
6387 unsigned long size, int cpu_id)
6391 mutex_lock(&trace_types_lock);
6393 if (cpu_id != RING_BUFFER_ALL_CPUS) {
6394 /* make sure, this cpu is enabled in the mask */
6395 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
6401 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
6406 mutex_unlock(&trace_types_lock);
6413 * tracing_update_buffers - used by tracing facility to expand ring buffers
6415 * To save on memory when the tracing is never used on a system with it
6416 * configured in. The ring buffers are set to a minimum size. But once
6417 * a user starts to use the tracing facility, then they need to grow
6418 * to their default size.
6420 * This function is to be called when a tracer is about to be used.
6422 int tracing_update_buffers(void)
6426 mutex_lock(&trace_types_lock);
6427 if (!ring_buffer_expanded)
6428 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
6429 RING_BUFFER_ALL_CPUS);
6430 mutex_unlock(&trace_types_lock);
6435 struct trace_option_dentry;
6438 create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
6441 * Used to clear out the tracer before deletion of an instance.
6442 * Must have trace_types_lock held.
6444 static void tracing_set_nop(struct trace_array *tr)
6446 if (tr->current_trace == &nop_trace)
6449 tr->current_trace->enabled--;
6451 if (tr->current_trace->reset)
6452 tr->current_trace->reset(tr);
6454 tr->current_trace = &nop_trace;
6457 static bool tracer_options_updated;
6459 static void add_tracer_options(struct trace_array *tr, struct tracer *t)
6461 /* Only enable if the directory has been created already. */
6465 /* Only create trace option files after update_tracer_options finish */
6466 if (!tracer_options_updated)
6469 create_trace_option_files(tr, t);
6472 int tracing_set_tracer(struct trace_array *tr, const char *buf)
6475 #ifdef CONFIG_TRACER_MAX_TRACE
6480 mutex_lock(&trace_types_lock);
6482 if (!ring_buffer_expanded) {
6483 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6484 RING_BUFFER_ALL_CPUS);
6490 for (t = trace_types; t; t = t->next) {
6491 if (strcmp(t->name, buf) == 0)
6498 if (t == tr->current_trace)
6501 #ifdef CONFIG_TRACER_SNAPSHOT
6502 if (t->use_max_tr) {
6503 local_irq_disable();
6504 arch_spin_lock(&tr->max_lock);
6505 if (tr->cond_snapshot)
6507 arch_spin_unlock(&tr->max_lock);
6513 /* Some tracers won't work on kernel command line */
6514 if (system_state < SYSTEM_RUNNING && t->noboot) {
6515 pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
6520 /* Some tracers are only allowed for the top level buffer */
6521 if (!trace_ok_for_array(t, tr)) {
6526 /* If trace pipe files are being read, we can't change the tracer */
6527 if (tr->trace_ref) {
6532 trace_branch_disable();
6534 tr->current_trace->enabled--;
6536 if (tr->current_trace->reset)
6537 tr->current_trace->reset(tr);
6539 #ifdef CONFIG_TRACER_MAX_TRACE
6540 had_max_tr = tr->current_trace->use_max_tr;
6542 /* Current trace needs to be nop_trace before synchronize_rcu */
6543 tr->current_trace = &nop_trace;
6545 if (had_max_tr && !t->use_max_tr) {
6547 * We need to make sure that the update_max_tr sees that
6548 * current_trace changed to nop_trace to keep it from
6549 * swapping the buffers after we resize it.
6550 * The update_max_tr is called from interrupts disabled
6551 * so a synchronized_sched() is sufficient.
6557 if (t->use_max_tr && !tr->allocated_snapshot) {
6558 ret = tracing_alloc_snapshot_instance(tr);
6563 tr->current_trace = &nop_trace;
6567 ret = tracer_init(t, tr);
6572 tr->current_trace = t;
6573 tr->current_trace->enabled++;
6574 trace_branch_enable(tr);
6576 mutex_unlock(&trace_types_lock);
6582 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
6583 size_t cnt, loff_t *ppos)
6585 struct trace_array *tr = filp->private_data;
6586 char buf[MAX_TRACER_SIZE+1];
6593 if (cnt > MAX_TRACER_SIZE)
6594 cnt = MAX_TRACER_SIZE;
6596 if (copy_from_user(buf, ubuf, cnt))
6603 err = tracing_set_tracer(tr, name);
6613 tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
6614 size_t cnt, loff_t *ppos)
6619 r = snprintf(buf, sizeof(buf), "%ld\n",
6620 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
6621 if (r > sizeof(buf))
6623 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6627 tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
6628 size_t cnt, loff_t *ppos)
6633 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6643 tracing_thresh_read(struct file *filp, char __user *ubuf,
6644 size_t cnt, loff_t *ppos)
6646 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
6650 tracing_thresh_write(struct file *filp, const char __user *ubuf,
6651 size_t cnt, loff_t *ppos)
6653 struct trace_array *tr = filp->private_data;
6656 mutex_lock(&trace_types_lock);
6657 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
6661 if (tr->current_trace->update_thresh) {
6662 ret = tr->current_trace->update_thresh(tr);
6669 mutex_unlock(&trace_types_lock);
6674 #ifdef CONFIG_TRACER_MAX_TRACE
6677 tracing_max_lat_read(struct file *filp, char __user *ubuf,
6678 size_t cnt, loff_t *ppos)
6680 return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
6684 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
6685 size_t cnt, loff_t *ppos)
6687 return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
6692 static int tracing_open_pipe(struct inode *inode, struct file *filp)
6694 struct trace_array *tr = inode->i_private;
6695 struct trace_iterator *iter;
6698 ret = tracing_check_open_get_tr(tr);
6702 mutex_lock(&trace_types_lock);
6704 /* create a buffer to store the information to pass to userspace */
6705 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6708 __trace_array_put(tr);
6712 trace_seq_init(&iter->seq);
6713 iter->trace = tr->current_trace;
6715 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
6720 /* trace pipe does not show start of buffer */
6721 cpumask_setall(iter->started);
6723 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
6724 iter->iter_flags |= TRACE_FILE_LAT_FMT;
6726 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6727 if (trace_clocks[tr->clock_id].in_ns)
6728 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
6731 iter->array_buffer = &tr->array_buffer;
6732 iter->cpu_file = tracing_get_cpu(inode);
6733 mutex_init(&iter->mutex);
6734 filp->private_data = iter;
6736 if (iter->trace->pipe_open)
6737 iter->trace->pipe_open(iter);
6739 nonseekable_open(inode, filp);
6743 mutex_unlock(&trace_types_lock);
6748 __trace_array_put(tr);
6749 mutex_unlock(&trace_types_lock);
6753 static int tracing_release_pipe(struct inode *inode, struct file *file)
6755 struct trace_iterator *iter = file->private_data;
6756 struct trace_array *tr = inode->i_private;
6758 mutex_lock(&trace_types_lock);
6762 if (iter->trace->pipe_close)
6763 iter->trace->pipe_close(iter);
6765 mutex_unlock(&trace_types_lock);
6767 free_trace_iter_content(iter);
6770 trace_array_put(tr);
6776 trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
6778 struct trace_array *tr = iter->tr;
6780 /* Iterators are static, they should be filled or empty */
6781 if (trace_buffer_iter(iter, iter->cpu_file))
6782 return EPOLLIN | EPOLLRDNORM;
6784 if (tr->trace_flags & TRACE_ITER_BLOCK)
6786 * Always select as readable when in blocking mode
6788 return EPOLLIN | EPOLLRDNORM;
6790 return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file,
6791 filp, poll_table, iter->tr->buffer_percent);
6795 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
6797 struct trace_iterator *iter = filp->private_data;
6799 return trace_poll(iter, filp, poll_table);
6802 /* Must be called with iter->mutex held. */
6803 static int tracing_wait_pipe(struct file *filp)
6805 struct trace_iterator *iter = filp->private_data;
6808 while (trace_empty(iter)) {
6810 if ((filp->f_flags & O_NONBLOCK)) {
6815 * We block until we read something and tracing is disabled.
6816 * We still block if tracing is disabled, but we have never
6817 * read anything. This allows a user to cat this file, and
6818 * then enable tracing. But after we have read something,
6819 * we give an EOF when tracing is again disabled.
6821 * iter->pos will be 0 if we haven't read anything.
6823 if (!tracer_tracing_is_on(iter->tr) && iter->pos)
6826 mutex_unlock(&iter->mutex);
6828 ret = wait_on_pipe(iter, 0);
6830 mutex_lock(&iter->mutex);
6843 tracing_read_pipe(struct file *filp, char __user *ubuf,
6844 size_t cnt, loff_t *ppos)
6846 struct trace_iterator *iter = filp->private_data;
6850 * Avoid more than one consumer on a single file descriptor
6851 * This is just a matter of traces coherency, the ring buffer itself
6854 mutex_lock(&iter->mutex);
6856 /* return any leftover data */
6857 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6861 trace_seq_init(&iter->seq);
6863 if (iter->trace->read) {
6864 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
6870 sret = tracing_wait_pipe(filp);
6874 /* stop when tracing is finished */
6875 if (trace_empty(iter)) {
6880 if (cnt >= PAGE_SIZE)
6881 cnt = PAGE_SIZE - 1;
6883 /* reset all but tr, trace, and overruns */
6884 trace_iterator_reset(iter);
6885 cpumask_clear(iter->started);
6886 trace_seq_init(&iter->seq);
6888 trace_event_read_lock();
6889 trace_access_lock(iter->cpu_file);
6890 while (trace_find_next_entry_inc(iter) != NULL) {
6891 enum print_line_t ret;
6892 int save_len = iter->seq.seq.len;
6894 ret = print_trace_line(iter);
6895 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6897 * If one print_trace_line() fills entire trace_seq in one shot,
6898 * trace_seq_to_user() will returns -EBUSY because save_len == 0,
6899 * In this case, we need to consume it, otherwise, loop will peek
6900 * this event next time, resulting in an infinite loop.
6902 if (save_len == 0) {
6904 trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
6905 trace_consume(iter);
6909 /* In other cases, don't print partial lines */
6910 iter->seq.seq.len = save_len;
6913 if (ret != TRACE_TYPE_NO_CONSUME)
6914 trace_consume(iter);
6916 if (trace_seq_used(&iter->seq) >= cnt)
6920 * Setting the full flag means we reached the trace_seq buffer
6921 * size and we should leave by partial output condition above.
6922 * One of the trace_seq_* functions is not used properly.
6924 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
6927 trace_access_unlock(iter->cpu_file);
6928 trace_event_read_unlock();
6930 /* Now copy what we have to the user */
6931 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6932 if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
6933 trace_seq_init(&iter->seq);
6936 * If there was nothing to send to user, in spite of consuming trace
6937 * entries, go back to wait for more entries.
6943 mutex_unlock(&iter->mutex);
6948 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
6951 __free_page(spd->pages[idx]);
6955 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
6961 /* Seq buffer is page-sized, exactly what we need. */
6963 save_len = iter->seq.seq.len;
6964 ret = print_trace_line(iter);
6966 if (trace_seq_has_overflowed(&iter->seq)) {
6967 iter->seq.seq.len = save_len;
6972 * This should not be hit, because it should only
6973 * be set if the iter->seq overflowed. But check it
6974 * anyway to be safe.
6976 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6977 iter->seq.seq.len = save_len;
6981 count = trace_seq_used(&iter->seq) - save_len;
6984 iter->seq.seq.len = save_len;
6988 if (ret != TRACE_TYPE_NO_CONSUME)
6989 trace_consume(iter);
6991 if (!trace_find_next_entry_inc(iter)) {
7001 static ssize_t tracing_splice_read_pipe(struct file *filp,
7003 struct pipe_inode_info *pipe,
7007 struct page *pages_def[PIPE_DEF_BUFFERS];
7008 struct partial_page partial_def[PIPE_DEF_BUFFERS];
7009 struct trace_iterator *iter = filp->private_data;
7010 struct splice_pipe_desc spd = {
7012 .partial = partial_def,
7013 .nr_pages = 0, /* This gets updated below. */
7014 .nr_pages_max = PIPE_DEF_BUFFERS,
7015 .ops = &default_pipe_buf_ops,
7016 .spd_release = tracing_spd_release_pipe,
7022 if (splice_grow_spd(pipe, &spd))
7025 mutex_lock(&iter->mutex);
7027 if (iter->trace->splice_read) {
7028 ret = iter->trace->splice_read(iter, filp,
7029 ppos, pipe, len, flags);
7034 ret = tracing_wait_pipe(filp);
7038 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
7043 trace_event_read_lock();
7044 trace_access_lock(iter->cpu_file);
7046 /* Fill as many pages as possible. */
7047 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
7048 spd.pages[i] = alloc_page(GFP_KERNEL);
7052 rem = tracing_fill_pipe_page(rem, iter);
7054 /* Copy the data into the page, so we can start over. */
7055 ret = trace_seq_to_buffer(&iter->seq,
7056 page_address(spd.pages[i]),
7057 trace_seq_used(&iter->seq));
7059 __free_page(spd.pages[i]);
7062 spd.partial[i].offset = 0;
7063 spd.partial[i].len = trace_seq_used(&iter->seq);
7065 trace_seq_init(&iter->seq);
7068 trace_access_unlock(iter->cpu_file);
7069 trace_event_read_unlock();
7070 mutex_unlock(&iter->mutex);
7075 ret = splice_to_pipe(pipe, &spd);
7079 splice_shrink_spd(&spd);
7083 mutex_unlock(&iter->mutex);
7088 tracing_entries_read(struct file *filp, char __user *ubuf,
7089 size_t cnt, loff_t *ppos)
7091 struct inode *inode = file_inode(filp);
7092 struct trace_array *tr = inode->i_private;
7093 int cpu = tracing_get_cpu(inode);
7098 mutex_lock(&trace_types_lock);
7100 if (cpu == RING_BUFFER_ALL_CPUS) {
7101 int cpu, buf_size_same;
7106 /* check if all cpu sizes are same */
7107 for_each_tracing_cpu(cpu) {
7108 /* fill in the size from first enabled cpu */
7110 size = per_cpu_ptr(tr->array_buffer.data, cpu)->entries;
7111 if (size != per_cpu_ptr(tr->array_buffer.data, cpu)->entries) {
7117 if (buf_size_same) {
7118 if (!ring_buffer_expanded)
7119 r = sprintf(buf, "%lu (expanded: %lu)\n",
7121 trace_buf_size >> 10);
7123 r = sprintf(buf, "%lu\n", size >> 10);
7125 r = sprintf(buf, "X\n");
7127 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10);
7129 mutex_unlock(&trace_types_lock);
7131 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7136 tracing_entries_write(struct file *filp, const char __user *ubuf,
7137 size_t cnt, loff_t *ppos)
7139 struct inode *inode = file_inode(filp);
7140 struct trace_array *tr = inode->i_private;
7144 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7148 /* must have at least 1 entry */
7152 /* value is in KB */
7154 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
7164 tracing_total_entries_read(struct file *filp, char __user *ubuf,
7165 size_t cnt, loff_t *ppos)
7167 struct trace_array *tr = filp->private_data;
7170 unsigned long size = 0, expanded_size = 0;
7172 mutex_lock(&trace_types_lock);
7173 for_each_tracing_cpu(cpu) {
7174 size += per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10;
7175 if (!ring_buffer_expanded)
7176 expanded_size += trace_buf_size >> 10;
7178 if (ring_buffer_expanded)
7179 r = sprintf(buf, "%lu\n", size);
7181 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
7182 mutex_unlock(&trace_types_lock);
7184 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7188 tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
7189 size_t cnt, loff_t *ppos)
7192 * There is no need to read what the user has written, this function
7193 * is just to make sure that there is no error when "echo" is used
7202 tracing_free_buffer_release(struct inode *inode, struct file *filp)
7204 struct trace_array *tr = inode->i_private;
7206 /* disable tracing ? */
7207 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
7208 tracer_tracing_off(tr);
7209 /* resize the ring buffer to 0 */
7210 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
7212 trace_array_put(tr);
7218 tracing_mark_write(struct file *filp, const char __user *ubuf,
7219 size_t cnt, loff_t *fpos)
7221 struct trace_array *tr = filp->private_data;
7222 struct ring_buffer_event *event;
7223 enum event_trigger_type tt = ETT_NONE;
7224 struct trace_buffer *buffer;
7225 struct print_entry *entry;
7230 /* Used in tracing_mark_raw_write() as well */
7231 #define FAULTED_STR "<faulted>"
7232 #define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
7234 if (tracing_disabled)
7237 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7240 if (cnt > TRACE_BUF_SIZE)
7241 cnt = TRACE_BUF_SIZE;
7243 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
7245 size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
7247 /* If less than "<faulted>", then make sure we can still add that */
7248 if (cnt < FAULTED_SIZE)
7249 size += FAULTED_SIZE - cnt;
7251 buffer = tr->array_buffer.buffer;
7252 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
7254 if (unlikely(!event))
7255 /* Ring buffer disabled, return as if not open for write */
7258 entry = ring_buffer_event_data(event);
7259 entry->ip = _THIS_IP_;
7261 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
7263 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7269 if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
7270 /* do not add \n before testing triggers, but add \0 */
7271 entry->buf[cnt] = '\0';
7272 tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event);
7275 if (entry->buf[cnt - 1] != '\n') {
7276 entry->buf[cnt] = '\n';
7277 entry->buf[cnt + 1] = '\0';
7279 entry->buf[cnt] = '\0';
7281 if (static_branch_unlikely(&trace_marker_exports_enabled))
7282 ftrace_exports(event, TRACE_EXPORT_MARKER);
7283 __buffer_unlock_commit(buffer, event);
7286 event_triggers_post_call(tr->trace_marker_file, tt);
7291 /* Limit it for now to 3K (including tag) */
7292 #define RAW_DATA_MAX_SIZE (1024*3)
7295 tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
7296 size_t cnt, loff_t *fpos)
7298 struct trace_array *tr = filp->private_data;
7299 struct ring_buffer_event *event;
7300 struct trace_buffer *buffer;
7301 struct raw_data_entry *entry;
7306 #define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
7308 if (tracing_disabled)
7311 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7314 /* The marker must at least have a tag id */
7315 if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
7318 if (cnt > TRACE_BUF_SIZE)
7319 cnt = TRACE_BUF_SIZE;
7321 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
7323 size = sizeof(*entry) + cnt;
7324 if (cnt < FAULT_SIZE_ID)
7325 size += FAULT_SIZE_ID - cnt;
7327 buffer = tr->array_buffer.buffer;
7328 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
7331 /* Ring buffer disabled, return as if not open for write */
7334 entry = ring_buffer_event_data(event);
7336 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
7339 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7344 __buffer_unlock_commit(buffer, event);
7349 static int tracing_clock_show(struct seq_file *m, void *v)
7351 struct trace_array *tr = m->private;
7354 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
7356 "%s%s%s%s", i ? " " : "",
7357 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
7358 i == tr->clock_id ? "]" : "");
7364 int tracing_set_clock(struct trace_array *tr, const char *clockstr)
7368 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
7369 if (strcmp(trace_clocks[i].name, clockstr) == 0)
7372 if (i == ARRAY_SIZE(trace_clocks))
7375 mutex_lock(&trace_types_lock);
7379 ring_buffer_set_clock(tr->array_buffer.buffer, trace_clocks[i].func);
7382 * New clock may not be consistent with the previous clock.
7383 * Reset the buffer so that it doesn't have incomparable timestamps.
7385 tracing_reset_online_cpus(&tr->array_buffer);
7387 #ifdef CONFIG_TRACER_MAX_TRACE
7388 if (tr->max_buffer.buffer)
7389 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
7390 tracing_reset_online_cpus(&tr->max_buffer);
7393 mutex_unlock(&trace_types_lock);
7398 static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
7399 size_t cnt, loff_t *fpos)
7401 struct seq_file *m = filp->private_data;
7402 struct trace_array *tr = m->private;
7404 const char *clockstr;
7407 if (cnt >= sizeof(buf))
7410 if (copy_from_user(buf, ubuf, cnt))
7415 clockstr = strstrip(buf);
7417 ret = tracing_set_clock(tr, clockstr);
7426 static int tracing_clock_open(struct inode *inode, struct file *file)
7428 struct trace_array *tr = inode->i_private;
7431 ret = tracing_check_open_get_tr(tr);
7435 ret = single_open(file, tracing_clock_show, inode->i_private);
7437 trace_array_put(tr);
7442 static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
7444 struct trace_array *tr = m->private;
7446 mutex_lock(&trace_types_lock);
7448 if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
7449 seq_puts(m, "delta [absolute]\n");
7451 seq_puts(m, "[delta] absolute\n");
7453 mutex_unlock(&trace_types_lock);
7458 static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
7460 struct trace_array *tr = inode->i_private;
7463 ret = tracing_check_open_get_tr(tr);
7467 ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
7469 trace_array_put(tr);
7474 u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
7476 if (rbe == this_cpu_read(trace_buffered_event))
7477 return ring_buffer_time_stamp(buffer);
7479 return ring_buffer_event_time_stamp(buffer, rbe);
7483 * Set or disable using the per CPU trace_buffer_event when possible.
7485 int tracing_set_filter_buffering(struct trace_array *tr, bool set)
7489 mutex_lock(&trace_types_lock);
7491 if (set && tr->no_filter_buffering_ref++)
7495 if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) {
7500 --tr->no_filter_buffering_ref;
7503 mutex_unlock(&trace_types_lock);
7508 struct ftrace_buffer_info {
7509 struct trace_iterator iter;
7511 unsigned int spare_cpu;
7515 #ifdef CONFIG_TRACER_SNAPSHOT
7516 static int tracing_snapshot_open(struct inode *inode, struct file *file)
7518 struct trace_array *tr = inode->i_private;
7519 struct trace_iterator *iter;
7523 ret = tracing_check_open_get_tr(tr);
7527 if (file->f_mode & FMODE_READ) {
7528 iter = __tracing_open(inode, file, true);
7530 ret = PTR_ERR(iter);
7532 /* Writes still need the seq_file to hold the private data */
7534 m = kzalloc(sizeof(*m), GFP_KERNEL);
7537 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
7545 iter->array_buffer = &tr->max_buffer;
7546 iter->cpu_file = tracing_get_cpu(inode);
7548 file->private_data = m;
7552 trace_array_put(tr);
7558 tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
7561 struct seq_file *m = filp->private_data;
7562 struct trace_iterator *iter = m->private;
7563 struct trace_array *tr = iter->tr;
7567 ret = tracing_update_buffers();
7571 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7575 mutex_lock(&trace_types_lock);
7577 if (tr->current_trace->use_max_tr) {
7582 local_irq_disable();
7583 arch_spin_lock(&tr->max_lock);
7584 if (tr->cond_snapshot)
7586 arch_spin_unlock(&tr->max_lock);
7593 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7597 if (tr->allocated_snapshot)
7601 /* Only allow per-cpu swap if the ring buffer supports it */
7602 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
7603 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7608 if (tr->allocated_snapshot)
7609 ret = resize_buffer_duplicate_size(&tr->max_buffer,
7610 &tr->array_buffer, iter->cpu_file);
7612 ret = tracing_alloc_snapshot_instance(tr);
7615 local_irq_disable();
7616 /* Now, we're going to swap */
7617 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7618 update_max_tr(tr, current, smp_processor_id(), NULL);
7620 update_max_tr_single(tr, current, iter->cpu_file);
7624 if (tr->allocated_snapshot) {
7625 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7626 tracing_reset_online_cpus(&tr->max_buffer);
7628 tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
7638 mutex_unlock(&trace_types_lock);
7642 static int tracing_snapshot_release(struct inode *inode, struct file *file)
7644 struct seq_file *m = file->private_data;
7647 ret = tracing_release(inode, file);
7649 if (file->f_mode & FMODE_READ)
7652 /* If write only, the seq_file is just a stub */
7660 static int tracing_buffers_open(struct inode *inode, struct file *filp);
7661 static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
7662 size_t count, loff_t *ppos);
7663 static int tracing_buffers_release(struct inode *inode, struct file *file);
7664 static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
7665 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
7667 static int snapshot_raw_open(struct inode *inode, struct file *filp)
7669 struct ftrace_buffer_info *info;
7672 /* The following checks for tracefs lockdown */
7673 ret = tracing_buffers_open(inode, filp);
7677 info = filp->private_data;
7679 if (info->iter.trace->use_max_tr) {
7680 tracing_buffers_release(inode, filp);
7684 info->iter.snapshot = true;
7685 info->iter.array_buffer = &info->iter.tr->max_buffer;
7690 #endif /* CONFIG_TRACER_SNAPSHOT */
7693 static const struct file_operations tracing_thresh_fops = {
7694 .open = tracing_open_generic,
7695 .read = tracing_thresh_read,
7696 .write = tracing_thresh_write,
7697 .llseek = generic_file_llseek,
7700 #ifdef CONFIG_TRACER_MAX_TRACE
7701 static const struct file_operations tracing_max_lat_fops = {
7702 .open = tracing_open_generic,
7703 .read = tracing_max_lat_read,
7704 .write = tracing_max_lat_write,
7705 .llseek = generic_file_llseek,
7709 static const struct file_operations set_tracer_fops = {
7710 .open = tracing_open_generic,
7711 .read = tracing_set_trace_read,
7712 .write = tracing_set_trace_write,
7713 .llseek = generic_file_llseek,
7716 static const struct file_operations tracing_pipe_fops = {
7717 .open = tracing_open_pipe,
7718 .poll = tracing_poll_pipe,
7719 .read = tracing_read_pipe,
7720 .splice_read = tracing_splice_read_pipe,
7721 .release = tracing_release_pipe,
7722 .llseek = no_llseek,
7725 static const struct file_operations tracing_entries_fops = {
7726 .open = tracing_open_generic_tr,
7727 .read = tracing_entries_read,
7728 .write = tracing_entries_write,
7729 .llseek = generic_file_llseek,
7730 .release = tracing_release_generic_tr,
7733 static const struct file_operations tracing_total_entries_fops = {
7734 .open = tracing_open_generic_tr,
7735 .read = tracing_total_entries_read,
7736 .llseek = generic_file_llseek,
7737 .release = tracing_release_generic_tr,
7740 static const struct file_operations tracing_free_buffer_fops = {
7741 .open = tracing_open_generic_tr,
7742 .write = tracing_free_buffer_write,
7743 .release = tracing_free_buffer_release,
7746 static const struct file_operations tracing_mark_fops = {
7747 .open = tracing_mark_open,
7748 .write = tracing_mark_write,
7749 .release = tracing_release_generic_tr,
7752 static const struct file_operations tracing_mark_raw_fops = {
7753 .open = tracing_mark_open,
7754 .write = tracing_mark_raw_write,
7755 .release = tracing_release_generic_tr,
7758 static const struct file_operations trace_clock_fops = {
7759 .open = tracing_clock_open,
7761 .llseek = seq_lseek,
7762 .release = tracing_single_release_tr,
7763 .write = tracing_clock_write,
7766 static const struct file_operations trace_time_stamp_mode_fops = {
7767 .open = tracing_time_stamp_mode_open,
7769 .llseek = seq_lseek,
7770 .release = tracing_single_release_tr,
7773 #ifdef CONFIG_TRACER_SNAPSHOT
7774 static const struct file_operations snapshot_fops = {
7775 .open = tracing_snapshot_open,
7777 .write = tracing_snapshot_write,
7778 .llseek = tracing_lseek,
7779 .release = tracing_snapshot_release,
7782 static const struct file_operations snapshot_raw_fops = {
7783 .open = snapshot_raw_open,
7784 .read = tracing_buffers_read,
7785 .release = tracing_buffers_release,
7786 .splice_read = tracing_buffers_splice_read,
7787 .llseek = no_llseek,
7790 #endif /* CONFIG_TRACER_SNAPSHOT */
7793 * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
7794 * @filp: The active open file structure
7795 * @ubuf: The userspace provided buffer to read value into
7796 * @cnt: The maximum number of bytes to read
7797 * @ppos: The current "file" position
7799 * This function implements the write interface for a struct trace_min_max_param.
7800 * The filp->private_data must point to a trace_min_max_param structure that
7801 * defines where to write the value, the min and the max acceptable values,
7802 * and a lock to protect the write.
7805 trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
7807 struct trace_min_max_param *param = filp->private_data;
7814 err = kstrtoull_from_user(ubuf, cnt, 10, &val);
7819 mutex_lock(param->lock);
7821 if (param->min && val < *param->min)
7824 if (param->max && val > *param->max)
7831 mutex_unlock(param->lock);
7840 * trace_min_max_read - Read a u64 value from a trace_min_max_param struct
7841 * @filp: The active open file structure
7842 * @ubuf: The userspace provided buffer to read value into
7843 * @cnt: The maximum number of bytes to read
7844 * @ppos: The current "file" position
7846 * This function implements the read interface for a struct trace_min_max_param.
7847 * The filp->private_data must point to a trace_min_max_param struct with valid
7851 trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
7853 struct trace_min_max_param *param = filp->private_data;
7854 char buf[U64_STR_SIZE];
7863 if (cnt > sizeof(buf))
7866 len = snprintf(buf, sizeof(buf), "%llu\n", val);
7868 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
7871 const struct file_operations trace_min_max_fops = {
7872 .open = tracing_open_generic,
7873 .read = trace_min_max_read,
7874 .write = trace_min_max_write,
7877 #define TRACING_LOG_ERRS_MAX 8
7878 #define TRACING_LOG_LOC_MAX 128
7880 #define CMD_PREFIX " Command: "
7883 const char **errs; /* ptr to loc-specific array of err strings */
7884 u8 type; /* index into errs -> specific err string */
7885 u16 pos; /* caret position */
7889 struct tracing_log_err {
7890 struct list_head list;
7891 struct err_info info;
7892 char loc[TRACING_LOG_LOC_MAX]; /* err location */
7893 char *cmd; /* what caused err */
7896 static DEFINE_MUTEX(tracing_err_log_lock);
7898 static struct tracing_log_err *alloc_tracing_log_err(int len)
7900 struct tracing_log_err *err;
7902 err = kzalloc(sizeof(*err), GFP_KERNEL);
7904 return ERR_PTR(-ENOMEM);
7906 err->cmd = kzalloc(len, GFP_KERNEL);
7909 return ERR_PTR(-ENOMEM);
7915 static void free_tracing_log_err(struct tracing_log_err *err)
7921 static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr,
7924 struct tracing_log_err *err;
7927 if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
7928 err = alloc_tracing_log_err(len);
7929 if (PTR_ERR(err) != -ENOMEM)
7930 tr->n_err_log_entries++;
7934 cmd = kzalloc(len, GFP_KERNEL);
7936 return ERR_PTR(-ENOMEM);
7937 err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
7940 list_del(&err->list);
7946 * err_pos - find the position of a string within a command for error careting
7947 * @cmd: The tracing command that caused the error
7948 * @str: The string to position the caret at within @cmd
7950 * Finds the position of the first occurrence of @str within @cmd. The
7951 * return value can be passed to tracing_log_err() for caret placement
7954 * Returns the index within @cmd of the first occurrence of @str or 0
7955 * if @str was not found.
7957 unsigned int err_pos(char *cmd, const char *str)
7961 if (WARN_ON(!strlen(cmd)))
7964 found = strstr(cmd, str);
7972 * tracing_log_err - write an error to the tracing error log
7973 * @tr: The associated trace array for the error (NULL for top level array)
7974 * @loc: A string describing where the error occurred
7975 * @cmd: The tracing command that caused the error
7976 * @errs: The array of loc-specific static error strings
7977 * @type: The index into errs[], which produces the specific static err string
7978 * @pos: The position the caret should be placed in the cmd
7980 * Writes an error into tracing/error_log of the form:
7982 * <loc>: error: <text>
7986 * tracing/error_log is a small log file containing the last
7987 * TRACING_LOG_ERRS_MAX errors (8). Memory for errors isn't allocated
7988 * unless there has been a tracing error, and the error log can be
7989 * cleared and have its memory freed by writing the empty string in
7990 * truncation mode to it i.e. echo > tracing/error_log.
7992 * NOTE: the @errs array along with the @type param are used to
7993 * produce a static error string - this string is not copied and saved
7994 * when the error is logged - only a pointer to it is saved. See
7995 * existing callers for examples of how static strings are typically
7996 * defined for use with tracing_log_err().
7998 void tracing_log_err(struct trace_array *tr,
7999 const char *loc, const char *cmd,
8000 const char **errs, u8 type, u16 pos)
8002 struct tracing_log_err *err;
8008 len += sizeof(CMD_PREFIX) + 2 * sizeof("\n") + strlen(cmd) + 1;
8010 mutex_lock(&tracing_err_log_lock);
8011 err = get_tracing_log_err(tr, len);
8012 if (PTR_ERR(err) == -ENOMEM) {
8013 mutex_unlock(&tracing_err_log_lock);
8017 snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
8018 snprintf(err->cmd, len, "\n" CMD_PREFIX "%s\n", cmd);
8020 err->info.errs = errs;
8021 err->info.type = type;
8022 err->info.pos = pos;
8023 err->info.ts = local_clock();
8025 list_add_tail(&err->list, &tr->err_log);
8026 mutex_unlock(&tracing_err_log_lock);
8029 static void clear_tracing_err_log(struct trace_array *tr)
8031 struct tracing_log_err *err, *next;
8033 mutex_lock(&tracing_err_log_lock);
8034 list_for_each_entry_safe(err, next, &tr->err_log, list) {
8035 list_del(&err->list);
8036 free_tracing_log_err(err);
8039 tr->n_err_log_entries = 0;
8040 mutex_unlock(&tracing_err_log_lock);
8043 static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
8045 struct trace_array *tr = m->private;
8047 mutex_lock(&tracing_err_log_lock);
8049 return seq_list_start(&tr->err_log, *pos);
8052 static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
8054 struct trace_array *tr = m->private;
8056 return seq_list_next(v, &tr->err_log, pos);
8059 static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
8061 mutex_unlock(&tracing_err_log_lock);
8064 static void tracing_err_log_show_pos(struct seq_file *m, u16 pos)
8068 for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
8070 for (i = 0; i < pos; i++)
8075 static int tracing_err_log_seq_show(struct seq_file *m, void *v)
8077 struct tracing_log_err *err = v;
8080 const char *err_text = err->info.errs[err->info.type];
8081 u64 sec = err->info.ts;
8084 nsec = do_div(sec, NSEC_PER_SEC);
8085 seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
8086 err->loc, err_text);
8087 seq_printf(m, "%s", err->cmd);
8088 tracing_err_log_show_pos(m, err->info.pos);
8094 static const struct seq_operations tracing_err_log_seq_ops = {
8095 .start = tracing_err_log_seq_start,
8096 .next = tracing_err_log_seq_next,
8097 .stop = tracing_err_log_seq_stop,
8098 .show = tracing_err_log_seq_show
8101 static int tracing_err_log_open(struct inode *inode, struct file *file)
8103 struct trace_array *tr = inode->i_private;
8106 ret = tracing_check_open_get_tr(tr);
8110 /* If this file was opened for write, then erase contents */
8111 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
8112 clear_tracing_err_log(tr);
8114 if (file->f_mode & FMODE_READ) {
8115 ret = seq_open(file, &tracing_err_log_seq_ops);
8117 struct seq_file *m = file->private_data;
8120 trace_array_put(tr);
8126 static ssize_t tracing_err_log_write(struct file *file,
8127 const char __user *buffer,
8128 size_t count, loff_t *ppos)
8133 static int tracing_err_log_release(struct inode *inode, struct file *file)
8135 struct trace_array *tr = inode->i_private;
8137 trace_array_put(tr);
8139 if (file->f_mode & FMODE_READ)
8140 seq_release(inode, file);
8145 static const struct file_operations tracing_err_log_fops = {
8146 .open = tracing_err_log_open,
8147 .write = tracing_err_log_write,
8149 .llseek = tracing_lseek,
8150 .release = tracing_err_log_release,
8153 static int tracing_buffers_open(struct inode *inode, struct file *filp)
8155 struct trace_array *tr = inode->i_private;
8156 struct ftrace_buffer_info *info;
8159 ret = tracing_check_open_get_tr(tr);
8163 info = kvzalloc(sizeof(*info), GFP_KERNEL);
8165 trace_array_put(tr);
8169 mutex_lock(&trace_types_lock);
8172 info->iter.cpu_file = tracing_get_cpu(inode);
8173 info->iter.trace = tr->current_trace;
8174 info->iter.array_buffer = &tr->array_buffer;
8176 /* Force reading ring buffer for first read */
8177 info->read = (unsigned int)-1;
8179 filp->private_data = info;
8183 mutex_unlock(&trace_types_lock);
8185 ret = nonseekable_open(inode, filp);
8187 trace_array_put(tr);
8193 tracing_buffers_poll(struct file *filp, poll_table *poll_table)
8195 struct ftrace_buffer_info *info = filp->private_data;
8196 struct trace_iterator *iter = &info->iter;
8198 return trace_poll(iter, filp, poll_table);
8202 tracing_buffers_read(struct file *filp, char __user *ubuf,
8203 size_t count, loff_t *ppos)
8205 struct ftrace_buffer_info *info = filp->private_data;
8206 struct trace_iterator *iter = &info->iter;
8213 #ifdef CONFIG_TRACER_MAX_TRACE
8214 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8219 info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer,
8221 if (IS_ERR(info->spare)) {
8222 ret = PTR_ERR(info->spare);
8225 info->spare_cpu = iter->cpu_file;
8231 /* Do we have previous read data to read? */
8232 if (info->read < PAGE_SIZE)
8236 trace_access_lock(iter->cpu_file);
8237 ret = ring_buffer_read_page(iter->array_buffer->buffer,
8241 trace_access_unlock(iter->cpu_file);
8244 if (trace_empty(iter)) {
8245 if ((filp->f_flags & O_NONBLOCK))
8248 ret = wait_on_pipe(iter, 0);
8259 size = PAGE_SIZE - info->read;
8263 ret = copy_to_user(ubuf, info->spare + info->read, size);
8275 static int tracing_buffers_release(struct inode *inode, struct file *file)
8277 struct ftrace_buffer_info *info = file->private_data;
8278 struct trace_iterator *iter = &info->iter;
8280 mutex_lock(&trace_types_lock);
8282 iter->tr->trace_ref--;
8284 __trace_array_put(iter->tr);
8287 /* Make sure the waiters see the new wait_index */
8290 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
8293 ring_buffer_free_read_page(iter->array_buffer->buffer,
8294 info->spare_cpu, info->spare);
8297 mutex_unlock(&trace_types_lock);
8303 struct trace_buffer *buffer;
8306 refcount_t refcount;
8309 static void buffer_ref_release(struct buffer_ref *ref)
8311 if (!refcount_dec_and_test(&ref->refcount))
8313 ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
8317 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
8318 struct pipe_buffer *buf)
8320 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8322 buffer_ref_release(ref);
8326 static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
8327 struct pipe_buffer *buf)
8329 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8331 if (refcount_read(&ref->refcount) > INT_MAX/2)
8334 refcount_inc(&ref->refcount);
8338 /* Pipe buffer operations for a buffer. */
8339 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
8340 .release = buffer_pipe_buf_release,
8341 .get = buffer_pipe_buf_get,
8345 * Callback from splice_to_pipe(), if we need to release some pages
8346 * at the end of the spd in case we error'ed out in filling the pipe.
8348 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
8350 struct buffer_ref *ref =
8351 (struct buffer_ref *)spd->partial[i].private;
8353 buffer_ref_release(ref);
8354 spd->partial[i].private = 0;
8358 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
8359 struct pipe_inode_info *pipe, size_t len,
8362 struct ftrace_buffer_info *info = file->private_data;
8363 struct trace_iterator *iter = &info->iter;
8364 struct partial_page partial_def[PIPE_DEF_BUFFERS];
8365 struct page *pages_def[PIPE_DEF_BUFFERS];
8366 struct splice_pipe_desc spd = {
8368 .partial = partial_def,
8369 .nr_pages_max = PIPE_DEF_BUFFERS,
8370 .ops = &buffer_pipe_buf_ops,
8371 .spd_release = buffer_spd_release,
8373 struct buffer_ref *ref;
8377 #ifdef CONFIG_TRACER_MAX_TRACE
8378 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8382 if (*ppos & (PAGE_SIZE - 1))
8385 if (len & (PAGE_SIZE - 1)) {
8386 if (len < PAGE_SIZE)
8391 if (splice_grow_spd(pipe, &spd))
8395 trace_access_lock(iter->cpu_file);
8396 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8398 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
8402 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
8408 refcount_set(&ref->refcount, 1);
8409 ref->buffer = iter->array_buffer->buffer;
8410 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
8411 if (IS_ERR(ref->page)) {
8412 ret = PTR_ERR(ref->page);
8417 ref->cpu = iter->cpu_file;
8419 r = ring_buffer_read_page(ref->buffer, &ref->page,
8420 len, iter->cpu_file, 1);
8422 ring_buffer_free_read_page(ref->buffer, ref->cpu,
8428 page = virt_to_page(ref->page);
8430 spd.pages[i] = page;
8431 spd.partial[i].len = PAGE_SIZE;
8432 spd.partial[i].offset = 0;
8433 spd.partial[i].private = (unsigned long)ref;
8437 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8440 trace_access_unlock(iter->cpu_file);
8443 /* did we read anything? */
8444 if (!spd.nr_pages) {
8451 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
8454 wait_index = READ_ONCE(iter->wait_index);
8456 ret = wait_on_pipe(iter, iter->tr->buffer_percent);
8460 /* No need to wait after waking up when tracing is off */
8461 if (!tracer_tracing_is_on(iter->tr))
8464 /* Make sure we see the new wait_index */
8466 if (wait_index != iter->wait_index)
8472 ret = splice_to_pipe(pipe, &spd);
8474 splice_shrink_spd(&spd);
8479 /* An ioctl call with cmd 0 to the ring buffer file will wake up all waiters */
8480 static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
8482 struct ftrace_buffer_info *info = file->private_data;
8483 struct trace_iterator *iter = &info->iter;
8486 return -ENOIOCTLCMD;
8488 mutex_lock(&trace_types_lock);
8491 /* Make sure the waiters see the new wait_index */
8494 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
8496 mutex_unlock(&trace_types_lock);
8500 static const struct file_operations tracing_buffers_fops = {
8501 .open = tracing_buffers_open,
8502 .read = tracing_buffers_read,
8503 .poll = tracing_buffers_poll,
8504 .release = tracing_buffers_release,
8505 .splice_read = tracing_buffers_splice_read,
8506 .unlocked_ioctl = tracing_buffers_ioctl,
8507 .llseek = no_llseek,
8511 tracing_stats_read(struct file *filp, char __user *ubuf,
8512 size_t count, loff_t *ppos)
8514 struct inode *inode = file_inode(filp);
8515 struct trace_array *tr = inode->i_private;
8516 struct array_buffer *trace_buf = &tr->array_buffer;
8517 int cpu = tracing_get_cpu(inode);
8518 struct trace_seq *s;
8520 unsigned long long t;
8521 unsigned long usec_rem;
8523 s = kmalloc(sizeof(*s), GFP_KERNEL);
8529 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
8530 trace_seq_printf(s, "entries: %ld\n", cnt);
8532 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
8533 trace_seq_printf(s, "overrun: %ld\n", cnt);
8535 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
8536 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
8538 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
8539 trace_seq_printf(s, "bytes: %ld\n", cnt);
8541 if (trace_clocks[tr->clock_id].in_ns) {
8542 /* local or global for trace_clock */
8543 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8544 usec_rem = do_div(t, USEC_PER_SEC);
8545 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
8548 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer));
8549 usec_rem = do_div(t, USEC_PER_SEC);
8550 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
8552 /* counter or tsc mode for trace_clock */
8553 trace_seq_printf(s, "oldest event ts: %llu\n",
8554 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8556 trace_seq_printf(s, "now ts: %llu\n",
8557 ring_buffer_time_stamp(trace_buf->buffer));
8560 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
8561 trace_seq_printf(s, "dropped events: %ld\n", cnt);
8563 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
8564 trace_seq_printf(s, "read events: %ld\n", cnt);
8566 count = simple_read_from_buffer(ubuf, count, ppos,
8567 s->buffer, trace_seq_used(s));
8574 static const struct file_operations tracing_stats_fops = {
8575 .open = tracing_open_generic_tr,
8576 .read = tracing_stats_read,
8577 .llseek = generic_file_llseek,
8578 .release = tracing_release_generic_tr,
8581 #ifdef CONFIG_DYNAMIC_FTRACE
8584 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
8585 size_t cnt, loff_t *ppos)
8591 /* 256 should be plenty to hold the amount needed */
8592 buf = kmalloc(256, GFP_KERNEL);
8596 r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n",
8597 ftrace_update_tot_cnt,
8598 ftrace_number_of_pages,
8599 ftrace_number_of_groups);
8601 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8606 static const struct file_operations tracing_dyn_info_fops = {
8607 .open = tracing_open_generic,
8608 .read = tracing_read_dyn_info,
8609 .llseek = generic_file_llseek,
8611 #endif /* CONFIG_DYNAMIC_FTRACE */
8613 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
8615 ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
8616 struct trace_array *tr, struct ftrace_probe_ops *ops,
8619 tracing_snapshot_instance(tr);
8623 ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
8624 struct trace_array *tr, struct ftrace_probe_ops *ops,
8627 struct ftrace_func_mapper *mapper = data;
8631 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8641 tracing_snapshot_instance(tr);
8645 ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
8646 struct ftrace_probe_ops *ops, void *data)
8648 struct ftrace_func_mapper *mapper = data;
8651 seq_printf(m, "%ps:", (void *)ip);
8653 seq_puts(m, "snapshot");
8656 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8659 seq_printf(m, ":count=%ld\n", *count);
8661 seq_puts(m, ":unlimited\n");
8667 ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
8668 unsigned long ip, void *init_data, void **data)
8670 struct ftrace_func_mapper *mapper = *data;
8673 mapper = allocate_ftrace_func_mapper();
8679 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
8683 ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
8684 unsigned long ip, void *data)
8686 struct ftrace_func_mapper *mapper = data;
8691 free_ftrace_func_mapper(mapper, NULL);
8695 ftrace_func_mapper_remove_ip(mapper, ip);
8698 static struct ftrace_probe_ops snapshot_probe_ops = {
8699 .func = ftrace_snapshot,
8700 .print = ftrace_snapshot_print,
8703 static struct ftrace_probe_ops snapshot_count_probe_ops = {
8704 .func = ftrace_count_snapshot,
8705 .print = ftrace_snapshot_print,
8706 .init = ftrace_snapshot_init,
8707 .free = ftrace_snapshot_free,
8711 ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
8712 char *glob, char *cmd, char *param, int enable)
8714 struct ftrace_probe_ops *ops;
8715 void *count = (void *)-1;
8722 /* hash funcs only work with set_ftrace_filter */
8726 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
8729 return unregister_ftrace_function_probe_func(glob+1, tr, ops);
8734 number = strsep(¶m, ":");
8736 if (!strlen(number))
8740 * We use the callback data field (which is a pointer)
8743 ret = kstrtoul(number, 0, (unsigned long *)&count);
8748 ret = tracing_alloc_snapshot_instance(tr);
8752 ret = register_ftrace_function_probe(glob, tr, ops, count);
8755 return ret < 0 ? ret : 0;
8758 static struct ftrace_func_command ftrace_snapshot_cmd = {
8760 .func = ftrace_trace_snapshot_callback,
8763 static __init int register_snapshot_cmd(void)
8765 return register_ftrace_command(&ftrace_snapshot_cmd);
8768 static inline __init int register_snapshot_cmd(void) { return 0; }
8769 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
8771 static struct dentry *tracing_get_dentry(struct trace_array *tr)
8773 if (WARN_ON(!tr->dir))
8774 return ERR_PTR(-ENODEV);
8776 /* Top directory uses NULL as the parent */
8777 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
8780 /* All sub buffers have a descriptor */
8784 static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
8786 struct dentry *d_tracer;
8789 return tr->percpu_dir;
8791 d_tracer = tracing_get_dentry(tr);
8792 if (IS_ERR(d_tracer))
8795 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
8797 MEM_FAIL(!tr->percpu_dir,
8798 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
8800 return tr->percpu_dir;
8803 static struct dentry *
8804 trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
8805 void *data, long cpu, const struct file_operations *fops)
8807 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
8809 if (ret) /* See tracing_get_cpu() */
8810 d_inode(ret)->i_cdev = (void *)(cpu + 1);
8815 tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
8817 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
8818 struct dentry *d_cpu;
8819 char cpu_dir[30]; /* 30 characters should be more than enough */
8824 snprintf(cpu_dir, 30, "cpu%ld", cpu);
8825 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
8827 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
8831 /* per cpu trace_pipe */
8832 trace_create_cpu_file("trace_pipe", TRACE_MODE_READ, d_cpu,
8833 tr, cpu, &tracing_pipe_fops);
8836 trace_create_cpu_file("trace", TRACE_MODE_WRITE, d_cpu,
8837 tr, cpu, &tracing_fops);
8839 trace_create_cpu_file("trace_pipe_raw", TRACE_MODE_READ, d_cpu,
8840 tr, cpu, &tracing_buffers_fops);
8842 trace_create_cpu_file("stats", TRACE_MODE_READ, d_cpu,
8843 tr, cpu, &tracing_stats_fops);
8845 trace_create_cpu_file("buffer_size_kb", TRACE_MODE_READ, d_cpu,
8846 tr, cpu, &tracing_entries_fops);
8848 #ifdef CONFIG_TRACER_SNAPSHOT
8849 trace_create_cpu_file("snapshot", TRACE_MODE_WRITE, d_cpu,
8850 tr, cpu, &snapshot_fops);
8852 trace_create_cpu_file("snapshot_raw", TRACE_MODE_READ, d_cpu,
8853 tr, cpu, &snapshot_raw_fops);
8857 #ifdef CONFIG_FTRACE_SELFTEST
8858 /* Let selftest have access to static functions in this file */
8859 #include "trace_selftest.c"
8863 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
8866 struct trace_option_dentry *topt = filp->private_data;
8869 if (topt->flags->val & topt->opt->bit)
8874 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
8878 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
8881 struct trace_option_dentry *topt = filp->private_data;
8885 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8889 if (val != 0 && val != 1)
8892 if (!!(topt->flags->val & topt->opt->bit) != val) {
8893 mutex_lock(&trace_types_lock);
8894 ret = __set_tracer_option(topt->tr, topt->flags,
8896 mutex_unlock(&trace_types_lock);
8907 static const struct file_operations trace_options_fops = {
8908 .open = tracing_open_generic,
8909 .read = trace_options_read,
8910 .write = trace_options_write,
8911 .llseek = generic_file_llseek,
8915 * In order to pass in both the trace_array descriptor as well as the index
8916 * to the flag that the trace option file represents, the trace_array
8917 * has a character array of trace_flags_index[], which holds the index
8918 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
8919 * The address of this character array is passed to the flag option file
8920 * read/write callbacks.
8922 * In order to extract both the index and the trace_array descriptor,
8923 * get_tr_index() uses the following algorithm.
8927 * As the pointer itself contains the address of the index (remember
8930 * Then to get the trace_array descriptor, by subtracting that index
8931 * from the ptr, we get to the start of the index itself.
8933 * ptr - idx == &index[0]
8935 * Then a simple container_of() from that pointer gets us to the
8936 * trace_array descriptor.
8938 static void get_tr_index(void *data, struct trace_array **ptr,
8939 unsigned int *pindex)
8941 *pindex = *(unsigned char *)data;
8943 *ptr = container_of(data - *pindex, struct trace_array,
8948 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
8951 void *tr_index = filp->private_data;
8952 struct trace_array *tr;
8956 get_tr_index(tr_index, &tr, &index);
8958 if (tr->trace_flags & (1 << index))
8963 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
8967 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
8970 void *tr_index = filp->private_data;
8971 struct trace_array *tr;
8976 get_tr_index(tr_index, &tr, &index);
8978 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8982 if (val != 0 && val != 1)
8985 mutex_lock(&event_mutex);
8986 mutex_lock(&trace_types_lock);
8987 ret = set_tracer_flag(tr, 1 << index, val);
8988 mutex_unlock(&trace_types_lock);
8989 mutex_unlock(&event_mutex);
8999 static const struct file_operations trace_options_core_fops = {
9000 .open = tracing_open_generic,
9001 .read = trace_options_core_read,
9002 .write = trace_options_core_write,
9003 .llseek = generic_file_llseek,
9006 struct dentry *trace_create_file(const char *name,
9008 struct dentry *parent,
9010 const struct file_operations *fops)
9014 ret = tracefs_create_file(name, mode, parent, data, fops);
9016 pr_warn("Could not create tracefs '%s' entry\n", name);
9022 static struct dentry *trace_options_init_dentry(struct trace_array *tr)
9024 struct dentry *d_tracer;
9029 d_tracer = tracing_get_dentry(tr);
9030 if (IS_ERR(d_tracer))
9033 tr->options = tracefs_create_dir("options", d_tracer);
9035 pr_warn("Could not create tracefs directory 'options'\n");
9043 create_trace_option_file(struct trace_array *tr,
9044 struct trace_option_dentry *topt,
9045 struct tracer_flags *flags,
9046 struct tracer_opt *opt)
9048 struct dentry *t_options;
9050 t_options = trace_options_init_dentry(tr);
9054 topt->flags = flags;
9058 topt->entry = trace_create_file(opt->name, TRACE_MODE_WRITE,
9059 t_options, topt, &trace_options_fops);
9064 create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
9066 struct trace_option_dentry *topts;
9067 struct trace_options *tr_topts;
9068 struct tracer_flags *flags;
9069 struct tracer_opt *opts;
9076 flags = tracer->flags;
9078 if (!flags || !flags->opts)
9082 * If this is an instance, only create flags for tracers
9083 * the instance may have.
9085 if (!trace_ok_for_array(tracer, tr))
9088 for (i = 0; i < tr->nr_topts; i++) {
9089 /* Make sure there's no duplicate flags. */
9090 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
9096 for (cnt = 0; opts[cnt].name; cnt++)
9099 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
9103 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
9110 tr->topts = tr_topts;
9111 tr->topts[tr->nr_topts].tracer = tracer;
9112 tr->topts[tr->nr_topts].topts = topts;
9115 for (cnt = 0; opts[cnt].name; cnt++) {
9116 create_trace_option_file(tr, &topts[cnt], flags,
9118 MEM_FAIL(topts[cnt].entry == NULL,
9119 "Failed to create trace option: %s",
9124 static struct dentry *
9125 create_trace_option_core_file(struct trace_array *tr,
9126 const char *option, long index)
9128 struct dentry *t_options;
9130 t_options = trace_options_init_dentry(tr);
9134 return trace_create_file(option, TRACE_MODE_WRITE, t_options,
9135 (void *)&tr->trace_flags_index[index],
9136 &trace_options_core_fops);
9139 static void create_trace_options_dir(struct trace_array *tr)
9141 struct dentry *t_options;
9142 bool top_level = tr == &global_trace;
9145 t_options = trace_options_init_dentry(tr);
9149 for (i = 0; trace_options[i]; i++) {
9151 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
9152 create_trace_option_core_file(tr, trace_options[i], i);
9157 rb_simple_read(struct file *filp, char __user *ubuf,
9158 size_t cnt, loff_t *ppos)
9160 struct trace_array *tr = filp->private_data;
9164 r = tracer_tracing_is_on(tr);
9165 r = sprintf(buf, "%d\n", r);
9167 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9171 rb_simple_write(struct file *filp, const char __user *ubuf,
9172 size_t cnt, loff_t *ppos)
9174 struct trace_array *tr = filp->private_data;
9175 struct trace_buffer *buffer = tr->array_buffer.buffer;
9179 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9184 mutex_lock(&trace_types_lock);
9185 if (!!val == tracer_tracing_is_on(tr)) {
9186 val = 0; /* do nothing */
9188 tracer_tracing_on(tr);
9189 if (tr->current_trace->start)
9190 tr->current_trace->start(tr);
9192 tracer_tracing_off(tr);
9193 if (tr->current_trace->stop)
9194 tr->current_trace->stop(tr);
9195 /* Wake up any waiters */
9196 ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS);
9198 mutex_unlock(&trace_types_lock);
9206 static const struct file_operations rb_simple_fops = {
9207 .open = tracing_open_generic_tr,
9208 .read = rb_simple_read,
9209 .write = rb_simple_write,
9210 .release = tracing_release_generic_tr,
9211 .llseek = default_llseek,
9215 buffer_percent_read(struct file *filp, char __user *ubuf,
9216 size_t cnt, loff_t *ppos)
9218 struct trace_array *tr = filp->private_data;
9222 r = tr->buffer_percent;
9223 r = sprintf(buf, "%d\n", r);
9225 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9229 buffer_percent_write(struct file *filp, const char __user *ubuf,
9230 size_t cnt, loff_t *ppos)
9232 struct trace_array *tr = filp->private_data;
9236 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9243 tr->buffer_percent = val;
9250 static const struct file_operations buffer_percent_fops = {
9251 .open = tracing_open_generic_tr,
9252 .read = buffer_percent_read,
9253 .write = buffer_percent_write,
9254 .release = tracing_release_generic_tr,
9255 .llseek = default_llseek,
9258 static struct dentry *trace_instance_dir;
9261 init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
9264 allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
9266 enum ring_buffer_flags rb_flags;
9268 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
9272 buf->buffer = ring_buffer_alloc(size, rb_flags);
9276 buf->data = alloc_percpu(struct trace_array_cpu);
9278 ring_buffer_free(buf->buffer);
9283 /* Allocate the first page for all buffers */
9284 set_buffer_entries(&tr->array_buffer,
9285 ring_buffer_size(tr->array_buffer.buffer, 0));
9290 static void free_trace_buffer(struct array_buffer *buf)
9293 ring_buffer_free(buf->buffer);
9295 free_percpu(buf->data);
9300 static int allocate_trace_buffers(struct trace_array *tr, int size)
9304 ret = allocate_trace_buffer(tr, &tr->array_buffer, size);
9308 #ifdef CONFIG_TRACER_MAX_TRACE
9309 ret = allocate_trace_buffer(tr, &tr->max_buffer,
9310 allocate_snapshot ? size : 1);
9311 if (MEM_FAIL(ret, "Failed to allocate trace buffer\n")) {
9312 free_trace_buffer(&tr->array_buffer);
9315 tr->allocated_snapshot = allocate_snapshot;
9317 allocate_snapshot = false;
9323 static void free_trace_buffers(struct trace_array *tr)
9328 free_trace_buffer(&tr->array_buffer);
9330 #ifdef CONFIG_TRACER_MAX_TRACE
9331 free_trace_buffer(&tr->max_buffer);
9335 static void init_trace_flags_index(struct trace_array *tr)
9339 /* Used by the trace options files */
9340 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
9341 tr->trace_flags_index[i] = i;
9344 static void __update_tracer_options(struct trace_array *tr)
9348 for (t = trace_types; t; t = t->next)
9349 add_tracer_options(tr, t);
9352 static void update_tracer_options(struct trace_array *tr)
9354 mutex_lock(&trace_types_lock);
9355 tracer_options_updated = true;
9356 __update_tracer_options(tr);
9357 mutex_unlock(&trace_types_lock);
9360 /* Must have trace_types_lock held */
9361 struct trace_array *trace_array_find(const char *instance)
9363 struct trace_array *tr, *found = NULL;
9365 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9366 if (tr->name && strcmp(tr->name, instance) == 0) {
9375 struct trace_array *trace_array_find_get(const char *instance)
9377 struct trace_array *tr;
9379 mutex_lock(&trace_types_lock);
9380 tr = trace_array_find(instance);
9383 mutex_unlock(&trace_types_lock);
9388 static int trace_array_create_dir(struct trace_array *tr)
9392 tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);
9396 ret = event_trace_add_tracer(tr->dir, tr);
9398 tracefs_remove(tr->dir);
9402 init_tracer_tracefs(tr, tr->dir);
9403 __update_tracer_options(tr);
9408 static struct trace_array *trace_array_create(const char *name)
9410 struct trace_array *tr;
9414 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
9416 return ERR_PTR(ret);
9418 tr->name = kstrdup(name, GFP_KERNEL);
9422 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
9425 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
9427 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
9429 raw_spin_lock_init(&tr->start_lock);
9431 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
9433 tr->current_trace = &nop_trace;
9435 INIT_LIST_HEAD(&tr->systems);
9436 INIT_LIST_HEAD(&tr->events);
9437 INIT_LIST_HEAD(&tr->hist_vars);
9438 INIT_LIST_HEAD(&tr->err_log);
9440 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
9443 if (ftrace_allocate_ftrace_ops(tr) < 0)
9446 ftrace_init_trace_array(tr);
9448 init_trace_flags_index(tr);
9450 if (trace_instance_dir) {
9451 ret = trace_array_create_dir(tr);
9455 __trace_early_add_events(tr);
9457 list_add(&tr->list, &ftrace_trace_arrays);
9464 ftrace_free_ftrace_ops(tr);
9465 free_trace_buffers(tr);
9466 free_cpumask_var(tr->tracing_cpumask);
9470 return ERR_PTR(ret);
9473 static int instance_mkdir(const char *name)
9475 struct trace_array *tr;
9478 mutex_lock(&event_mutex);
9479 mutex_lock(&trace_types_lock);
9482 if (trace_array_find(name))
9485 tr = trace_array_create(name);
9487 ret = PTR_ERR_OR_ZERO(tr);
9490 mutex_unlock(&trace_types_lock);
9491 mutex_unlock(&event_mutex);
9496 * trace_array_get_by_name - Create/Lookup a trace array, given its name.
9497 * @name: The name of the trace array to be looked up/created.
9499 * Returns pointer to trace array with given name.
9500 * NULL, if it cannot be created.
9502 * NOTE: This function increments the reference counter associated with the
9503 * trace array returned. This makes sure it cannot be freed while in use.
9504 * Use trace_array_put() once the trace array is no longer needed.
9505 * If the trace_array is to be freed, trace_array_destroy() needs to
9506 * be called after the trace_array_put(), or simply let user space delete
9507 * it from the tracefs instances directory. But until the
9508 * trace_array_put() is called, user space can not delete it.
9511 struct trace_array *trace_array_get_by_name(const char *name)
9513 struct trace_array *tr;
9515 mutex_lock(&event_mutex);
9516 mutex_lock(&trace_types_lock);
9518 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9519 if (tr->name && strcmp(tr->name, name) == 0)
9523 tr = trace_array_create(name);
9531 mutex_unlock(&trace_types_lock);
9532 mutex_unlock(&event_mutex);
9535 EXPORT_SYMBOL_GPL(trace_array_get_by_name);
9537 static int __remove_instance(struct trace_array *tr)
9541 /* Reference counter for a newly created trace array = 1. */
9542 if (tr->ref > 1 || (tr->current_trace && tr->trace_ref))
9545 list_del(&tr->list);
9547 /* Disable all the flags that were enabled coming in */
9548 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
9549 if ((1 << i) & ZEROED_TRACE_FLAGS)
9550 set_tracer_flag(tr, 1 << i, 0);
9553 tracing_set_nop(tr);
9554 clear_ftrace_function_probes(tr);
9555 event_trace_del_tracer(tr);
9556 ftrace_clear_pids(tr);
9557 ftrace_destroy_function_files(tr);
9558 tracefs_remove(tr->dir);
9559 free_percpu(tr->last_func_repeats);
9560 free_trace_buffers(tr);
9561 clear_tracing_err_log(tr);
9563 for (i = 0; i < tr->nr_topts; i++) {
9564 kfree(tr->topts[i].topts);
9568 free_cpumask_var(tr->tracing_cpumask);
9575 int trace_array_destroy(struct trace_array *this_tr)
9577 struct trace_array *tr;
9583 mutex_lock(&event_mutex);
9584 mutex_lock(&trace_types_lock);
9588 /* Making sure trace array exists before destroying it. */
9589 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9590 if (tr == this_tr) {
9591 ret = __remove_instance(tr);
9596 mutex_unlock(&trace_types_lock);
9597 mutex_unlock(&event_mutex);
9601 EXPORT_SYMBOL_GPL(trace_array_destroy);
9603 static int instance_rmdir(const char *name)
9605 struct trace_array *tr;
9608 mutex_lock(&event_mutex);
9609 mutex_lock(&trace_types_lock);
9612 tr = trace_array_find(name);
9614 ret = __remove_instance(tr);
9616 mutex_unlock(&trace_types_lock);
9617 mutex_unlock(&event_mutex);
9622 static __init void create_trace_instances(struct dentry *d_tracer)
9624 struct trace_array *tr;
9626 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
9629 if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
9632 mutex_lock(&event_mutex);
9633 mutex_lock(&trace_types_lock);
9635 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9638 if (MEM_FAIL(trace_array_create_dir(tr) < 0,
9639 "Failed to create instance directory\n"))
9643 mutex_unlock(&trace_types_lock);
9644 mutex_unlock(&event_mutex);
9648 init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
9650 struct trace_event_file *file;
9653 trace_create_file("available_tracers", TRACE_MODE_READ, d_tracer,
9654 tr, &show_traces_fops);
9656 trace_create_file("current_tracer", TRACE_MODE_WRITE, d_tracer,
9657 tr, &set_tracer_fops);
9659 trace_create_file("tracing_cpumask", TRACE_MODE_WRITE, d_tracer,
9660 tr, &tracing_cpumask_fops);
9662 trace_create_file("trace_options", TRACE_MODE_WRITE, d_tracer,
9663 tr, &tracing_iter_fops);
9665 trace_create_file("trace", TRACE_MODE_WRITE, d_tracer,
9668 trace_create_file("trace_pipe", TRACE_MODE_READ, d_tracer,
9669 tr, &tracing_pipe_fops);
9671 trace_create_file("buffer_size_kb", TRACE_MODE_WRITE, d_tracer,
9672 tr, &tracing_entries_fops);
9674 trace_create_file("buffer_total_size_kb", TRACE_MODE_READ, d_tracer,
9675 tr, &tracing_total_entries_fops);
9677 trace_create_file("free_buffer", 0200, d_tracer,
9678 tr, &tracing_free_buffer_fops);
9680 trace_create_file("trace_marker", 0220, d_tracer,
9681 tr, &tracing_mark_fops);
9683 file = __find_event_file(tr, "ftrace", "print");
9684 if (file && file->dir)
9685 trace_create_file("trigger", TRACE_MODE_WRITE, file->dir,
9686 file, &event_trigger_fops);
9687 tr->trace_marker_file = file;
9689 trace_create_file("trace_marker_raw", 0220, d_tracer,
9690 tr, &tracing_mark_raw_fops);
9692 trace_create_file("trace_clock", TRACE_MODE_WRITE, d_tracer, tr,
9695 trace_create_file("tracing_on", TRACE_MODE_WRITE, d_tracer,
9696 tr, &rb_simple_fops);
9698 trace_create_file("timestamp_mode", TRACE_MODE_READ, d_tracer, tr,
9699 &trace_time_stamp_mode_fops);
9701 tr->buffer_percent = 50;
9703 trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
9704 tr, &buffer_percent_fops);
9706 create_trace_options_dir(tr);
9708 #ifdef CONFIG_TRACER_MAX_TRACE
9709 trace_create_maxlat_file(tr, d_tracer);
9712 if (ftrace_create_function_files(tr, d_tracer))
9713 MEM_FAIL(1, "Could not allocate function filter files");
9715 #ifdef CONFIG_TRACER_SNAPSHOT
9716 trace_create_file("snapshot", TRACE_MODE_WRITE, d_tracer,
9717 tr, &snapshot_fops);
9720 trace_create_file("error_log", TRACE_MODE_WRITE, d_tracer,
9721 tr, &tracing_err_log_fops);
9723 for_each_tracing_cpu(cpu)
9724 tracing_init_tracefs_percpu(tr, cpu);
9726 ftrace_init_tracefs(tr, d_tracer);
9729 static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
9731 struct vfsmount *mnt;
9732 struct file_system_type *type;
9735 * To maintain backward compatibility for tools that mount
9736 * debugfs to get to the tracing facility, tracefs is automatically
9737 * mounted to the debugfs/tracing directory.
9739 type = get_fs_type("tracefs");
9742 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
9743 put_filesystem(type);
9752 * tracing_init_dentry - initialize top level trace array
9754 * This is called when creating files or directories in the tracing
9755 * directory. It is called via fs_initcall() by any of the boot up code
9756 * and expects to return the dentry of the top level tracing directory.
9758 int tracing_init_dentry(void)
9760 struct trace_array *tr = &global_trace;
9762 if (security_locked_down(LOCKDOWN_TRACEFS)) {
9763 pr_warn("Tracing disabled due to lockdown\n");
9767 /* The top level trace array uses NULL as parent */
9771 if (WARN_ON(!tracefs_initialized()))
9775 * As there may still be users that expect the tracing
9776 * files to exist in debugfs/tracing, we must automount
9777 * the tracefs file system there, so older tools still
9778 * work with the newer kernel.
9780 tr->dir = debugfs_create_automount("tracing", NULL,
9781 trace_automount, NULL);
9786 extern struct trace_eval_map *__start_ftrace_eval_maps[];
9787 extern struct trace_eval_map *__stop_ftrace_eval_maps[];
9789 static struct workqueue_struct *eval_map_wq __initdata;
9790 static struct work_struct eval_map_work __initdata;
9791 static struct work_struct tracerfs_init_work __initdata;
9793 static void __init eval_map_work_func(struct work_struct *work)
9797 len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
9798 trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
9801 static int __init trace_eval_init(void)
9803 INIT_WORK(&eval_map_work, eval_map_work_func);
9805 eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0);
9807 pr_err("Unable to allocate eval_map_wq\n");
9809 eval_map_work_func(&eval_map_work);
9813 queue_work(eval_map_wq, &eval_map_work);
9817 subsys_initcall(trace_eval_init);
9819 static int __init trace_eval_sync(void)
9821 /* Make sure the eval map updates are finished */
9823 destroy_workqueue(eval_map_wq);
9827 late_initcall_sync(trace_eval_sync);
9830 #ifdef CONFIG_MODULES
9831 static void trace_module_add_evals(struct module *mod)
9833 if (!mod->num_trace_evals)
9837 * Modules with bad taint do not have events created, do
9838 * not bother with enums either.
9840 if (trace_module_has_bad_taint(mod))
9843 trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
9846 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
9847 static void trace_module_remove_evals(struct module *mod)
9849 union trace_eval_map_item *map;
9850 union trace_eval_map_item **last = &trace_eval_maps;
9852 if (!mod->num_trace_evals)
9855 mutex_lock(&trace_eval_mutex);
9857 map = trace_eval_maps;
9860 if (map->head.mod == mod)
9862 map = trace_eval_jmp_to_tail(map);
9863 last = &map->tail.next;
9864 map = map->tail.next;
9869 *last = trace_eval_jmp_to_tail(map)->tail.next;
9872 mutex_unlock(&trace_eval_mutex);
9875 static inline void trace_module_remove_evals(struct module *mod) { }
9876 #endif /* CONFIG_TRACE_EVAL_MAP_FILE */
9878 static int trace_module_notify(struct notifier_block *self,
9879 unsigned long val, void *data)
9881 struct module *mod = data;
9884 case MODULE_STATE_COMING:
9885 trace_module_add_evals(mod);
9887 case MODULE_STATE_GOING:
9888 trace_module_remove_evals(mod);
9895 static struct notifier_block trace_module_nb = {
9896 .notifier_call = trace_module_notify,
9899 #endif /* CONFIG_MODULES */
9901 static __init void tracer_init_tracefs_work_func(struct work_struct *work)
9906 init_tracer_tracefs(&global_trace, NULL);
9907 ftrace_init_tracefs_toplevel(&global_trace, NULL);
9909 trace_create_file("tracing_thresh", TRACE_MODE_WRITE, NULL,
9910 &global_trace, &tracing_thresh_fops);
9912 trace_create_file("README", TRACE_MODE_READ, NULL,
9913 NULL, &tracing_readme_fops);
9915 trace_create_file("saved_cmdlines", TRACE_MODE_READ, NULL,
9916 NULL, &tracing_saved_cmdlines_fops);
9918 trace_create_file("saved_cmdlines_size", TRACE_MODE_WRITE, NULL,
9919 NULL, &tracing_saved_cmdlines_size_fops);
9921 trace_create_file("saved_tgids", TRACE_MODE_READ, NULL,
9922 NULL, &tracing_saved_tgids_fops);
9924 trace_create_eval_file(NULL);
9926 #ifdef CONFIG_MODULES
9927 register_module_notifier(&trace_module_nb);
9930 #ifdef CONFIG_DYNAMIC_FTRACE
9931 trace_create_file("dyn_ftrace_total_info", TRACE_MODE_READ, NULL,
9932 NULL, &tracing_dyn_info_fops);
9935 create_trace_instances(NULL);
9937 update_tracer_options(&global_trace);
9940 static __init int tracer_init_tracefs(void)
9944 trace_access_lock_init();
9946 ret = tracing_init_dentry();
9951 INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func);
9952 queue_work(eval_map_wq, &tracerfs_init_work);
9954 tracer_init_tracefs_work_func(NULL);
9957 rv_init_interface();
9962 fs_initcall(tracer_init_tracefs);
9964 static int trace_die_panic_handler(struct notifier_block *self,
9965 unsigned long ev, void *unused);
9967 static struct notifier_block trace_panic_notifier = {
9968 .notifier_call = trace_die_panic_handler,
9969 .priority = INT_MAX - 1,
9972 static struct notifier_block trace_die_notifier = {
9973 .notifier_call = trace_die_panic_handler,
9974 .priority = INT_MAX - 1,
9978 * The idea is to execute the following die/panic callback early, in order
9979 * to avoid showing irrelevant information in the trace (like other panic
9980 * notifier functions); we are the 2nd to run, after hung_task/rcu_stall
9981 * warnings get disabled (to prevent potential log flooding).
9983 static int trace_die_panic_handler(struct notifier_block *self,
9984 unsigned long ev, void *unused)
9986 if (!ftrace_dump_on_oops)
9989 /* The die notifier requires DIE_OOPS to trigger */
9990 if (self == &trace_die_notifier && ev != DIE_OOPS)
9993 ftrace_dump(ftrace_dump_on_oops);
9999 * printk is set to max of 1024, we really don't need it that big.
10000 * Nothing should be printing 1000 characters anyway.
10002 #define TRACE_MAX_PRINT 1000
10005 * Define here KERN_TRACE so that we have one place to modify
10006 * it if we decide to change what log level the ftrace dump
10009 #define KERN_TRACE KERN_EMERG
10012 trace_printk_seq(struct trace_seq *s)
10014 /* Probably should print a warning here. */
10015 if (s->seq.len >= TRACE_MAX_PRINT)
10016 s->seq.len = TRACE_MAX_PRINT;
10019 * More paranoid code. Although the buffer size is set to
10020 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
10021 * an extra layer of protection.
10023 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
10024 s->seq.len = s->seq.size - 1;
10026 /* should be zero ended, but we are paranoid. */
10027 s->buffer[s->seq.len] = 0;
10029 printk(KERN_TRACE "%s", s->buffer);
10034 void trace_init_global_iter(struct trace_iterator *iter)
10036 iter->tr = &global_trace;
10037 iter->trace = iter->tr->current_trace;
10038 iter->cpu_file = RING_BUFFER_ALL_CPUS;
10039 iter->array_buffer = &global_trace.array_buffer;
10041 if (iter->trace && iter->trace->open)
10042 iter->trace->open(iter);
10044 /* Annotate start of buffers if we had overruns */
10045 if (ring_buffer_overruns(iter->array_buffer->buffer))
10046 iter->iter_flags |= TRACE_FILE_ANNOTATE;
10048 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
10049 if (trace_clocks[iter->tr->clock_id].in_ns)
10050 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
10052 /* Can not use kmalloc for iter.temp and iter.fmt */
10053 iter->temp = static_temp_buf;
10054 iter->temp_size = STATIC_TEMP_BUF_SIZE;
10055 iter->fmt = static_fmt_buf;
10056 iter->fmt_size = STATIC_FMT_BUF_SIZE;
10059 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
10061 /* use static because iter can be a bit big for the stack */
10062 static struct trace_iterator iter;
10063 static atomic_t dump_running;
10064 struct trace_array *tr = &global_trace;
10065 unsigned int old_userobj;
10066 unsigned long flags;
10069 /* Only allow one dump user at a time. */
10070 if (atomic_inc_return(&dump_running) != 1) {
10071 atomic_dec(&dump_running);
10076 * Always turn off tracing when we dump.
10077 * We don't need to show trace output of what happens
10078 * between multiple crashes.
10080 * If the user does a sysrq-z, then they can re-enable
10081 * tracing with echo 1 > tracing_on.
10085 local_irq_save(flags);
10087 /* Simulate the iterator */
10088 trace_init_global_iter(&iter);
10090 for_each_tracing_cpu(cpu) {
10091 atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10094 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
10096 /* don't look at user memory in panic mode */
10097 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
10099 switch (oops_dump_mode) {
10101 iter.cpu_file = RING_BUFFER_ALL_CPUS;
10104 iter.cpu_file = raw_smp_processor_id();
10109 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
10110 iter.cpu_file = RING_BUFFER_ALL_CPUS;
10113 printk(KERN_TRACE "Dumping ftrace buffer:\n");
10115 /* Did function tracer already get disabled? */
10116 if (ftrace_is_dead()) {
10117 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
10118 printk("# MAY BE MISSING FUNCTION EVENTS\n");
10122 * We need to stop all tracing on all CPUS to read
10123 * the next buffer. This is a bit expensive, but is
10124 * not done often. We fill all what we can read,
10125 * and then release the locks again.
10128 while (!trace_empty(&iter)) {
10131 printk(KERN_TRACE "---------------------------------\n");
10135 trace_iterator_reset(&iter);
10136 iter.iter_flags |= TRACE_FILE_LAT_FMT;
10138 if (trace_find_next_entry_inc(&iter) != NULL) {
10141 ret = print_trace_line(&iter);
10142 if (ret != TRACE_TYPE_NO_CONSUME)
10143 trace_consume(&iter);
10145 touch_nmi_watchdog();
10147 trace_printk_seq(&iter.seq);
10151 printk(KERN_TRACE " (ftrace buffer empty)\n");
10153 printk(KERN_TRACE "---------------------------------\n");
10156 tr->trace_flags |= old_userobj;
10158 for_each_tracing_cpu(cpu) {
10159 atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10161 atomic_dec(&dump_running);
10162 local_irq_restore(flags);
10164 EXPORT_SYMBOL_GPL(ftrace_dump);
10166 #define WRITE_BUFSIZE 4096
10168 ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
10169 size_t count, loff_t *ppos,
10170 int (*createfn)(const char *))
10172 char *kbuf, *buf, *tmp;
10177 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
10181 while (done < count) {
10182 size = count - done;
10184 if (size >= WRITE_BUFSIZE)
10185 size = WRITE_BUFSIZE - 1;
10187 if (copy_from_user(kbuf, buffer + done, size)) {
10194 tmp = strchr(buf, '\n');
10197 size = tmp - buf + 1;
10199 size = strlen(buf);
10200 if (done + size < count) {
10203 /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
10204 pr_warn("Line length is too long: Should be less than %d\n",
10205 WRITE_BUFSIZE - 2);
10212 /* Remove comments */
10213 tmp = strchr(buf, '#');
10218 ret = createfn(buf);
10223 } while (done < count);
10233 #ifdef CONFIG_TRACER_MAX_TRACE
10234 __init static bool tr_needs_alloc_snapshot(const char *name)
10237 int len = strlen(name);
10240 if (!boot_snapshot_index)
10243 if (strncmp(name, boot_snapshot_info, len) == 0 &&
10244 boot_snapshot_info[len] == '\t')
10247 test = kmalloc(strlen(name) + 3, GFP_KERNEL);
10251 sprintf(test, "\t%s\t", name);
10252 ret = strstr(boot_snapshot_info, test) == NULL;
10257 __init static void do_allocate_snapshot(const char *name)
10259 if (!tr_needs_alloc_snapshot(name))
10263 * When allocate_snapshot is set, the next call to
10264 * allocate_trace_buffers() (called by trace_array_get_by_name())
10265 * will allocate the snapshot buffer. That will alse clear
10268 allocate_snapshot = true;
10271 static inline void do_allocate_snapshot(const char *name) { }
10274 __init static void enable_instances(void)
10276 struct trace_array *tr;
10281 /* A tab is always appended */
10282 boot_instance_info[boot_instance_index - 1] = '\0';
10283 str = boot_instance_info;
10285 while ((curr_str = strsep(&str, "\t"))) {
10287 tok = strsep(&curr_str, ",");
10289 if (IS_ENABLED(CONFIG_TRACER_MAX_TRACE))
10290 do_allocate_snapshot(tok);
10292 tr = trace_array_get_by_name(tok);
10294 pr_warn("Failed to create instance buffer %s\n", curr_str);
10297 /* Allow user space to delete it */
10298 trace_array_put(tr);
10300 while ((tok = strsep(&curr_str, ","))) {
10301 early_enable_events(tr, tok, true);
10306 __init static int tracer_alloc_buffers(void)
10312 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10313 pr_warn("Tracing disabled due to lockdown\n");
10318 * Make sure we don't accidentally add more trace options
10319 * than we have bits for.
10321 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
10323 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
10326 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
10327 goto out_free_buffer_mask;
10329 /* Only allocate trace_printk buffers if a trace_printk exists */
10330 if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
10331 /* Must be called before global_trace.buffer is allocated */
10332 trace_printk_init_buffers();
10334 /* To save memory, keep the ring buffer size to its minimum */
10335 if (ring_buffer_expanded)
10336 ring_buf_size = trace_buf_size;
10340 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
10341 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
10343 raw_spin_lock_init(&global_trace.start_lock);
10346 * The prepare callbacks allocates some memory for the ring buffer. We
10347 * don't free the buffer if the CPU goes down. If we were to free
10348 * the buffer, then the user would lose any trace that was in the
10349 * buffer. The memory will be removed once the "instance" is removed.
10351 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
10352 "trace/RB:prepare", trace_rb_cpu_prepare,
10355 goto out_free_cpumask;
10356 /* Used for event triggers */
10358 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
10360 goto out_rm_hp_state;
10362 if (trace_create_savedcmd() < 0)
10363 goto out_free_temp_buffer;
10365 /* TODO: make the number of buffers hot pluggable with CPUS */
10366 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
10367 MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n");
10368 goto out_free_savedcmd;
10371 if (global_trace.buffer_disabled)
10374 if (trace_boot_clock) {
10375 ret = tracing_set_clock(&global_trace, trace_boot_clock);
10377 pr_warn("Trace clock %s not defined, going back to default\n",
10382 * register_tracer() might reference current_trace, so it
10383 * needs to be set before we register anything. This is
10384 * just a bootstrap of current_trace anyway.
10386 global_trace.current_trace = &nop_trace;
10388 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
10390 ftrace_init_global_array_ops(&global_trace);
10392 init_trace_flags_index(&global_trace);
10394 register_tracer(&nop_trace);
10396 /* Function tracing may start here (via kernel command line) */
10397 init_function_trace();
10399 /* All seems OK, enable tracing */
10400 tracing_disabled = 0;
10402 atomic_notifier_chain_register(&panic_notifier_list,
10403 &trace_panic_notifier);
10405 register_die_notifier(&trace_die_notifier);
10407 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
10409 INIT_LIST_HEAD(&global_trace.systems);
10410 INIT_LIST_HEAD(&global_trace.events);
10411 INIT_LIST_HEAD(&global_trace.hist_vars);
10412 INIT_LIST_HEAD(&global_trace.err_log);
10413 list_add(&global_trace.list, &ftrace_trace_arrays);
10415 apply_trace_boot_options();
10417 register_snapshot_cmd();
10424 free_saved_cmdlines_buffer(savedcmd);
10425 out_free_temp_buffer:
10426 ring_buffer_free(temp_buffer);
10428 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
10430 free_cpumask_var(global_trace.tracing_cpumask);
10431 out_free_buffer_mask:
10432 free_cpumask_var(tracing_buffer_mask);
10437 void __init ftrace_boot_snapshot(void)
10439 #ifdef CONFIG_TRACER_MAX_TRACE
10440 struct trace_array *tr;
10442 if (!snapshot_at_boot)
10445 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
10446 if (!tr->allocated_snapshot)
10449 tracing_snapshot_instance(tr);
10450 trace_array_puts(tr, "** Boot snapshot taken **\n");
10455 void __init early_trace_init(void)
10457 if (tracepoint_printk) {
10458 tracepoint_print_iter =
10459 kzalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
10460 if (MEM_FAIL(!tracepoint_print_iter,
10461 "Failed to allocate trace iterator\n"))
10462 tracepoint_printk = 0;
10464 static_key_enable(&tracepoint_printk_key.key);
10466 tracer_alloc_buffers();
10471 void __init trace_init(void)
10473 trace_event_init();
10475 if (boot_instance_index)
10476 enable_instances();
10479 __init static void clear_boot_tracer(void)
10482 * The default tracer at boot buffer is an init section.
10483 * This function is called in lateinit. If we did not
10484 * find the boot tracer, then clear it out, to prevent
10485 * later registration from accessing the buffer that is
10486 * about to be freed.
10488 if (!default_bootup_tracer)
10491 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
10492 default_bootup_tracer);
10493 default_bootup_tracer = NULL;
10496 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
10497 __init static void tracing_set_default_clock(void)
10499 /* sched_clock_stable() is determined in late_initcall */
10500 if (!trace_boot_clock && !sched_clock_stable()) {
10501 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10502 pr_warn("Can not set tracing clock due to lockdown\n");
10506 printk(KERN_WARNING
10507 "Unstable clock detected, switching default tracing clock to \"global\"\n"
10508 "If you want to keep using the local clock, then add:\n"
10509 " \"trace_clock=local\"\n"
10510 "on the kernel command line\n");
10511 tracing_set_clock(&global_trace, "global");
10515 static inline void tracing_set_default_clock(void) { }
10518 __init static int late_trace_init(void)
10520 if (tracepoint_printk && tracepoint_printk_stop_on_boot) {
10521 static_key_disable(&tracepoint_printk_key.key);
10522 tracepoint_printk = 0;
10525 tracing_set_default_clock();
10526 clear_boot_tracer();
10530 late_initcall_sync(late_trace_init);