From 726721a51838e3983023f906580722fc83f804ee Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Thu, 28 May 2020 14:32:37 -0500 Subject: [PATCH] tracing: Move synthetic events to a separate file With the addition of the in-kernel synthetic event API, synthetic events are no longer specifically tied to the histogram triggers. The synthetic event code is also making trace_event_hist.c very bloated, so for those reasons, move it to a separate file, trace_events_synth.c, along with a new trace_synth.h header file. Because synthetic events are now independent from hist triggers, add a new CONFIG_SYNTH_EVENTS config option, and have CONFIG_HIST_TRIGGERS select it, and have CONFIG_SYNTH_EVENT_GEN_TEST depend on it. Link: http://lkml.kernel.org/r/4d1fa1f85ed5982706ac44844ac92451dcb04715.1590693308.git.zanussi@kernel.org Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/Kconfig | 20 +- kernel/trace/Makefile | 1 + kernel/trace/trace_events_hist.c | 2071 +++---------------------------------- kernel/trace/trace_events_synth.c | 1789 ++++++++++++++++++++++++++++++++ kernel/trace/trace_synth.h | 36 + 5 files changed, 1989 insertions(+), 1928 deletions(-) create mode 100644 kernel/trace/trace_events_synth.c create mode 100644 kernel/trace/trace_synth.h diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 2aec937..75407d5 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -623,12 +623,30 @@ config TRACING_MAP generally used outside of that context, and is normally selected by tracers that use it. +config SYNTH_EVENTS + bool "Synthetic trace events" + select TRACING + select DYNAMIC_EVENTS + default n + help + Synthetic events are user-defined trace events that can be + used to combine data from other trace events or in fact any + data source. Synthetic events can be generated indirectly + via the trace() action of histogram triggers or directly + by way of an in-kernel API. + + See Documentation/trace/events.rst or + Documentation/trace/histogram.rst for details and examples. + + If in doubt, say N. + config HIST_TRIGGERS bool "Histogram triggers" depends on ARCH_HAVE_NMI_SAFE_CMPXCHG select TRACING_MAP select TRACING select DYNAMIC_EVENTS + select SYNTH_EVENTS default n help Hist triggers allow one or more arbitrary trace event fields @@ -824,7 +842,7 @@ config PREEMPTIRQ_DELAY_TEST config SYNTH_EVENT_GEN_TEST tristate "Test module for in-kernel synthetic event generation" - depends on HIST_TRIGGERS + depends on SYNTH_EVENTS help This option creates a test module to check the base functionality of in-kernel synthetic event definition and diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index f9dcd19..1d8aaa5 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -72,6 +72,7 @@ endif obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o obj-$(CONFIG_EVENT_TRACING) += trace_events_trigger.o obj-$(CONFIG_TRACE_EVENT_INJECT) += trace_events_inject.o +obj-$(CONFIG_SYNTH_EVENTS) += trace_events_synth.o obj-$(CONFIG_HIST_TRIGGERS) += trace_events_hist.o obj-$(CONFIG_BPF_EVENTS) += bpf_trace.o obj-$(CONFIG_KPROBE_EVENTS) += trace_kprobe.o diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 313227d..0b93354 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -19,13 +19,7 @@ #include #include "tracing_map.h" -#include "trace.h" -#include "trace_dynevent.h" - -#define SYNTH_SYSTEM "synthetic" -#define SYNTH_FIELDS_MAX 32 - -#define STR_VAR_LEN_MAX 32 /* must be multiple of sizeof(u64) */ +#include "trace_synth.h" #define ERRORS \ C(NONE, "No error"), \ @@ -380,69 +374,6 @@ struct hist_trigger_data { unsigned int n_save_var_str; }; -static int create_synth_event(int argc, const char **argv); -static int synth_event_show(struct seq_file *m, struct dyn_event *ev); -static int synth_event_release(struct dyn_event *ev); -static bool synth_event_is_busy(struct dyn_event *ev); -static bool synth_event_match(const char *system, const char *event, - int argc, const char **argv, struct dyn_event *ev); - -static struct dyn_event_operations synth_event_ops = { - .create = create_synth_event, - .show = synth_event_show, - .is_busy = synth_event_is_busy, - .free = synth_event_release, - .match = synth_event_match, -}; - -struct synth_field { - char *type; - char *name; - size_t size; - unsigned int offset; - bool is_signed; - bool is_string; -}; - -struct synth_event { - struct dyn_event devent; - int ref; - char *name; - struct synth_field **fields; - unsigned int n_fields; - unsigned int n_u64; - struct trace_event_class class; - struct trace_event_call call; - struct tracepoint *tp; - struct module *mod; -}; - -static bool is_synth_event(struct dyn_event *ev) -{ - return ev->ops == &synth_event_ops; -} - -static struct synth_event *to_synth_event(struct dyn_event *ev) -{ - return container_of(ev, struct synth_event, devent); -} - -static bool synth_event_is_busy(struct dyn_event *ev) -{ - struct synth_event *event = to_synth_event(ev); - - return event->ref != 0; -} - -static bool synth_event_match(const char *system, const char *event, - int argc, const char **argv, struct dyn_event *ev) -{ - struct synth_event *sev = to_synth_event(ev); - - return strcmp(sev->name, event) == 0 && - (!system || strcmp(system, SYNTH_SYSTEM) == 0); -} - struct action_data; typedef void (*action_fn_t) (struct hist_trigger_data *hist_data, @@ -490,1882 +421,202 @@ struct action_data { union { struct { char *event; - char *event_system; - } match_data; - - struct { - /* - * var_str contains the $-unstripped variable - * name referenced by var_ref, and used when - * printing the action. Because var_ref - * creation is deferred to create_actions(), - * we need a per-action way to save it until - * then, thus var_str. - */ - char *var_str; - - /* - * var_ref refers to the variable being - * tracked e.g onmax($var). - */ - struct hist_field *var_ref; - - /* - * track_var contains the 'invisible' tracking - * variable created to keep the current - * e.g. max value. - */ - struct hist_field *track_var; - - check_track_val_fn_t check_val; - action_fn_t save_data; - } track_data; - }; -}; - -struct track_data { - u64 track_val; - bool updated; - - unsigned int key_len; - void *key; - struct tracing_map_elt elt; - - struct action_data *action_data; - struct hist_trigger_data *hist_data; -}; - -struct hist_elt_data { - char *comm; - u64 *var_ref_vals; - char *field_var_str[SYNTH_FIELDS_MAX]; -}; - -struct snapshot_context { - struct tracing_map_elt *elt; - void *key; -}; - -static void track_data_free(struct track_data *track_data) -{ - struct hist_elt_data *elt_data; - - if (!track_data) - return; - - kfree(track_data->key); - - elt_data = track_data->elt.private_data; - if (elt_data) { - kfree(elt_data->comm); - kfree(elt_data); - } - - kfree(track_data); -} - -static struct track_data *track_data_alloc(unsigned int key_len, - struct action_data *action_data, - struct hist_trigger_data *hist_data) -{ - struct track_data *data = kzalloc(sizeof(*data), GFP_KERNEL); - struct hist_elt_data *elt_data; - - if (!data) - return ERR_PTR(-ENOMEM); - - data->key = kzalloc(key_len, GFP_KERNEL); - if (!data->key) { - track_data_free(data); - return ERR_PTR(-ENOMEM); - } - - data->key_len = key_len; - data->action_data = action_data; - data->hist_data = hist_data; - - elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL); - if (!elt_data) { - track_data_free(data); - return ERR_PTR(-ENOMEM); - } - data->elt.private_data = elt_data; - - elt_data->comm = kzalloc(TASK_COMM_LEN, GFP_KERNEL); - if (!elt_data->comm) { - track_data_free(data); - return ERR_PTR(-ENOMEM); - } - - return data; -} - -static char last_cmd[MAX_FILTER_STR_VAL]; -static char last_cmd_loc[MAX_FILTER_STR_VAL]; - -static int errpos(char *str) -{ - return err_pos(last_cmd, str); -} - -static void last_cmd_set(struct trace_event_file *file, char *str) -{ - const char *system = NULL, *name = NULL; - struct trace_event_call *call; - - if (!str) - return; - - strcpy(last_cmd, "hist:"); - strncat(last_cmd, str, MAX_FILTER_STR_VAL - 1 - sizeof("hist:")); - - if (file) { - call = file->event_call; - - system = call->class->system; - if (system) { - name = trace_event_name(call); - if (!name) - system = NULL; - } - } - - if (system) - snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, "hist:%s:%s", system, name); -} - -static void hist_err(struct trace_array *tr, u8 err_type, u8 err_pos) -{ - tracing_log_err(tr, last_cmd_loc, last_cmd, err_text, - err_type, err_pos); -} - -static void hist_err_clear(void) -{ - last_cmd[0] = '\0'; - last_cmd_loc[0] = '\0'; -} - -struct synth_trace_event { - struct trace_entry ent; - u64 fields[]; -}; - -static int synth_event_define_fields(struct trace_event_call *call) -{ - struct synth_trace_event trace; - int offset = offsetof(typeof(trace), fields); - struct synth_event *event = call->data; - unsigned int i, size, n_u64; - char *name, *type; - bool is_signed; - int ret = 0; - - for (i = 0, n_u64 = 0; i < event->n_fields; i++) { - size = event->fields[i]->size; - is_signed = event->fields[i]->is_signed; - type = event->fields[i]->type; - name = event->fields[i]->name; - ret = trace_define_field(call, type, name, offset, size, - is_signed, FILTER_OTHER); - if (ret) - break; - - event->fields[i]->offset = n_u64; - - if (event->fields[i]->is_string) { - offset += STR_VAR_LEN_MAX; - n_u64 += STR_VAR_LEN_MAX / sizeof(u64); - } else { - offset += sizeof(u64); - n_u64++; - } - } - - event->n_u64 = n_u64; - - return ret; -} - -static bool synth_field_signed(char *type) -{ - if (str_has_prefix(type, "u")) - return false; - if (strcmp(type, "gfp_t") == 0) - return false; - - return true; -} - -static int synth_field_is_string(char *type) -{ - if (strstr(type, "char[") != NULL) - return true; - - return false; -} - -static int synth_field_string_size(char *type) -{ - char buf[4], *end, *start; - unsigned int len; - int size, err; - - start = strstr(type, "char["); - if (start == NULL) - return -EINVAL; - start += sizeof("char[") - 1; - - end = strchr(type, ']'); - if (!end || end < start) - return -EINVAL; - - len = end - start; - if (len > 3) - return -EINVAL; - - strncpy(buf, start, len); - buf[len] = '\0'; - - err = kstrtouint(buf, 0, &size); - if (err) - return err; - - if (size > STR_VAR_LEN_MAX) - return -EINVAL; - - return size; -} - -static int synth_field_size(char *type) -{ - int size = 0; - - if (strcmp(type, "s64") == 0) - size = sizeof(s64); - else if (strcmp(type, "u64") == 0) - size = sizeof(u64); - else if (strcmp(type, "s32") == 0) - size = sizeof(s32); - else if (strcmp(type, "u32") == 0) - size = sizeof(u32); - else if (strcmp(type, "s16") == 0) - size = sizeof(s16); - else if (strcmp(type, "u16") == 0) - size = sizeof(u16); - else if (strcmp(type, "s8") == 0) - size = sizeof(s8); - else if (strcmp(type, "u8") == 0) - size = sizeof(u8); - else if (strcmp(type, "char") == 0) - size = sizeof(char); - else if (strcmp(type, "unsigned char") == 0) - size = sizeof(unsigned char); - else if (strcmp(type, "int") == 0) - size = sizeof(int); - else if (strcmp(type, "unsigned int") == 0) - size = sizeof(unsigned int); - else if (strcmp(type, "long") == 0) - size = sizeof(long); - else if (strcmp(type, "unsigned long") == 0) - size = sizeof(unsigned long); - else if (strcmp(type, "pid_t") == 0) - size = sizeof(pid_t); - else if (strcmp(type, "gfp_t") == 0) - size = sizeof(gfp_t); - else if (synth_field_is_string(type)) - size = synth_field_string_size(type); - - return size; -} - -static const char *synth_field_fmt(char *type) -{ - const char *fmt = "%llu"; - - if (strcmp(type, "s64") == 0) - fmt = "%lld"; - else if (strcmp(type, "u64") == 0) - fmt = "%llu"; - else if (strcmp(type, "s32") == 0) - fmt = "%d"; - else if (strcmp(type, "u32") == 0) - fmt = "%u"; - else if (strcmp(type, "s16") == 0) - fmt = "%d"; - else if (strcmp(type, "u16") == 0) - fmt = "%u"; - else if (strcmp(type, "s8") == 0) - fmt = "%d"; - else if (strcmp(type, "u8") == 0) - fmt = "%u"; - else if (strcmp(type, "char") == 0) - fmt = "%d"; - else if (strcmp(type, "unsigned char") == 0) - fmt = "%u"; - else if (strcmp(type, "int") == 0) - fmt = "%d"; - else if (strcmp(type, "unsigned int") == 0) - fmt = "%u"; - else if (strcmp(type, "long") == 0) - fmt = "%ld"; - else if (strcmp(type, "unsigned long") == 0) - fmt = "%lu"; - else if (strcmp(type, "pid_t") == 0) - fmt = "%d"; - else if (strcmp(type, "gfp_t") == 0) - fmt = "%x"; - else if (synth_field_is_string(type)) - fmt = "%s"; - - return fmt; -} - -static void print_synth_event_num_val(struct trace_seq *s, - char *print_fmt, char *name, - int size, u64 val, char *space) -{ - switch (size) { - case 1: - trace_seq_printf(s, print_fmt, name, (u8)val, space); - break; - - case 2: - trace_seq_printf(s, print_fmt, name, (u16)val, space); - break; - - case 4: - trace_seq_printf(s, print_fmt, name, (u32)val, space); - break; - - default: - trace_seq_printf(s, print_fmt, name, val, space); - break; - } -} - -static enum print_line_t print_synth_event(struct trace_iterator *iter, - int flags, - struct trace_event *event) -{ - struct trace_array *tr = iter->tr; - struct trace_seq *s = &iter->seq; - struct synth_trace_event *entry; - struct synth_event *se; - unsigned int i, n_u64; - char print_fmt[32]; - const char *fmt; - - entry = (struct synth_trace_event *)iter->ent; - se = container_of(event, struct synth_event, call.event); - - trace_seq_printf(s, "%s: ", se->name); - - for (i = 0, n_u64 = 0; i < se->n_fields; i++) { - if (trace_seq_has_overflowed(s)) - goto end; - - fmt = synth_field_fmt(se->fields[i]->type); - - /* parameter types */ - if (tr && tr->trace_flags & TRACE_ITER_VERBOSE) - trace_seq_printf(s, "%s ", fmt); - - snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt); - - /* parameter values */ - if (se->fields[i]->is_string) { - trace_seq_printf(s, print_fmt, se->fields[i]->name, - (char *)&entry->fields[n_u64], - i == se->n_fields - 1 ? "" : " "); - n_u64 += STR_VAR_LEN_MAX / sizeof(u64); - } else { - struct trace_print_flags __flags[] = { - __def_gfpflag_names, {-1, NULL} }; - char *space = (i == se->n_fields - 1 ? "" : " "); - - print_synth_event_num_val(s, print_fmt, - se->fields[i]->name, - se->fields[i]->size, - entry->fields[n_u64], - space); - - if (strcmp(se->fields[i]->type, "gfp_t") == 0) { - trace_seq_puts(s, " ("); - trace_print_flags_seq(s, "|", - entry->fields[n_u64], - __flags); - trace_seq_putc(s, ')'); - } - n_u64++; - } - } -end: - trace_seq_putc(s, '\n'); - - return trace_handle_return(s); -} - -static struct trace_event_functions synth_event_funcs = { - .trace = print_synth_event -}; - -static notrace void trace_event_raw_event_synth(void *__data, - u64 *var_ref_vals, - unsigned int *var_ref_idx) -{ - struct trace_event_file *trace_file = __data; - struct synth_trace_event *entry; - struct trace_event_buffer fbuffer; - struct trace_buffer *buffer; - struct synth_event *event; - unsigned int i, n_u64, val_idx; - int fields_size = 0; - - event = trace_file->event_call->data; - - if (trace_trigger_soft_disabled(trace_file)) - return; - - fields_size = event->n_u64 * sizeof(u64); - - /* - * Avoid ring buffer recursion detection, as this event - * is being performed within another event. - */ - buffer = trace_file->tr->array_buffer.buffer; - ring_buffer_nest_start(buffer); - - entry = trace_event_buffer_reserve(&fbuffer, trace_file, - sizeof(*entry) + fields_size); - if (!entry) - goto out; - - for (i = 0, n_u64 = 0; i < event->n_fields; i++) { - val_idx = var_ref_idx[i]; - if (event->fields[i]->is_string) { - char *str_val = (char *)(long)var_ref_vals[val_idx]; - char *str_field = (char *)&entry->fields[n_u64]; - - strscpy(str_field, str_val, STR_VAR_LEN_MAX); - n_u64 += STR_VAR_LEN_MAX / sizeof(u64); - } else { - struct synth_field *field = event->fields[i]; - u64 val = var_ref_vals[val_idx]; - - switch (field->size) { - case 1: - *(u8 *)&entry->fields[n_u64] = (u8)val; - break; - - case 2: - *(u16 *)&entry->fields[n_u64] = (u16)val; - break; - - case 4: - *(u32 *)&entry->fields[n_u64] = (u32)val; - break; - - default: - entry->fields[n_u64] = val; - break; - } - n_u64++; - } - } - - trace_event_buffer_commit(&fbuffer); -out: - ring_buffer_nest_end(buffer); -} - -static void free_synth_event_print_fmt(struct trace_event_call *call) -{ - if (call) { - kfree(call->print_fmt); - call->print_fmt = NULL; - } -} - -static int __set_synth_event_print_fmt(struct synth_event *event, - char *buf, int len) -{ - const char *fmt; - int pos = 0; - int i; - - /* When len=0, we just calculate the needed length */ -#define LEN_OR_ZERO (len ? len - pos : 0) - - pos += snprintf(buf + pos, LEN_OR_ZERO, "\""); - for (i = 0; i < event->n_fields; i++) { - fmt = synth_field_fmt(event->fields[i]->type); - pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s", - event->fields[i]->name, fmt, - i == event->n_fields - 1 ? "" : ", "); - } - pos += snprintf(buf + pos, LEN_OR_ZERO, "\""); - - for (i = 0; i < event->n_fields; i++) { - pos += snprintf(buf + pos, LEN_OR_ZERO, - ", REC->%s", event->fields[i]->name); - } - -#undef LEN_OR_ZERO - - /* return the length of print_fmt */ - return pos; -} - -static int set_synth_event_print_fmt(struct trace_event_call *call) -{ - struct synth_event *event = call->data; - char *print_fmt; - int len; - - /* First: called with 0 length to calculate the needed length */ - len = __set_synth_event_print_fmt(event, NULL, 0); - - print_fmt = kmalloc(len + 1, GFP_KERNEL); - if (!print_fmt) - return -ENOMEM; - - /* Second: actually write the @print_fmt */ - __set_synth_event_print_fmt(event, print_fmt, len + 1); - call->print_fmt = print_fmt; - - return 0; -} - -static void free_synth_field(struct synth_field *field) -{ - kfree(field->type); - kfree(field->name); - kfree(field); -} - -static struct synth_field *parse_synth_field(int argc, const char **argv, - int *consumed) -{ - struct synth_field *field; - const char *prefix = NULL, *field_type = argv[0], *field_name, *array; - int len, ret = 0; - - if (field_type[0] == ';') - field_type++; - - if (!strcmp(field_type, "unsigned")) { - if (argc < 3) - return ERR_PTR(-EINVAL); - prefix = "unsigned "; - field_type = argv[1]; - field_name = argv[2]; - *consumed = 3; - } else { - field_name = argv[1]; - *consumed = 2; - } - - field = kzalloc(sizeof(*field), GFP_KERNEL); - if (!field) - return ERR_PTR(-ENOMEM); - - len = strlen(field_name); - array = strchr(field_name, '['); - if (array) - len -= strlen(array); - else if (field_name[len - 1] == ';') - len--; - - field->name = kmemdup_nul(field_name, len, GFP_KERNEL); - if (!field->name) { - ret = -ENOMEM; - goto free; - } - - if (field_type[0] == ';') - field_type++; - len = strlen(field_type) + 1; - if (array) - len += strlen(array); - if (prefix) - len += strlen(prefix); - - field->type = kzalloc(len, GFP_KERNEL); - if (!field->type) { - ret = -ENOMEM; - goto free; - } - if (prefix) - strcat(field->type, prefix); - strcat(field->type, field_type); - if (array) { - strcat(field->type, array); - if (field->type[len - 1] == ';') - field->type[len - 1] = '\0'; - } - - field->size = synth_field_size(field->type); - if (!field->size) { - ret = -EINVAL; - goto free; - } - - if (synth_field_is_string(field->type)) - field->is_string = true; - - field->is_signed = synth_field_signed(field->type); - - out: - return field; - free: - free_synth_field(field); - field = ERR_PTR(ret); - goto out; -} - -static void free_synth_tracepoint(struct tracepoint *tp) -{ - if (!tp) - return; - - kfree(tp->name); - kfree(tp); -} - -static struct tracepoint *alloc_synth_tracepoint(char *name) -{ - struct tracepoint *tp; - - tp = kzalloc(sizeof(*tp), GFP_KERNEL); - if (!tp) - return ERR_PTR(-ENOMEM); - - tp->name = kstrdup(name, GFP_KERNEL); - if (!tp->name) { - kfree(tp); - return ERR_PTR(-ENOMEM); - } - - return tp; -} - -typedef void (*synth_probe_func_t) (void *__data, u64 *var_ref_vals, - unsigned int *var_ref_idx); - -static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals, - unsigned int *var_ref_idx) -{ - struct tracepoint *tp = event->tp; - - if (unlikely(atomic_read(&tp->key.enabled) > 0)) { - struct tracepoint_func *probe_func_ptr; - synth_probe_func_t probe_func; - void *__data; - - if (!(cpu_online(raw_smp_processor_id()))) - return; - - probe_func_ptr = rcu_dereference_sched((tp)->funcs); - if (probe_func_ptr) { - do { - probe_func = probe_func_ptr->func; - __data = probe_func_ptr->data; - probe_func(__data, var_ref_vals, var_ref_idx); - } while ((++probe_func_ptr)->func); - } - } -} - -static struct synth_event *find_synth_event(const char *name) -{ - struct dyn_event *pos; - struct synth_event *event; - - for_each_dyn_event(pos) { - if (!is_synth_event(pos)) - continue; - event = to_synth_event(pos); - if (strcmp(event->name, name) == 0) - return event; - } - - return NULL; -} - -static struct trace_event_fields synth_event_fields_array[] = { - { .type = TRACE_FUNCTION_TYPE, - .define_fields = synth_event_define_fields }, - {} -}; - -static int register_synth_event(struct synth_event *event) -{ - struct trace_event_call *call = &event->call; - int ret = 0; - - event->call.class = &event->class; - event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL); - if (!event->class.system) { - ret = -ENOMEM; - goto out; - } - - event->tp = alloc_synth_tracepoint(event->name); - if (IS_ERR(event->tp)) { - ret = PTR_ERR(event->tp); - event->tp = NULL; - goto out; - } - - INIT_LIST_HEAD(&call->class->fields); - call->event.funcs = &synth_event_funcs; - call->class->fields_array = synth_event_fields_array; - - ret = register_trace_event(&call->event); - if (!ret) { - ret = -ENODEV; - goto out; - } - call->flags = TRACE_EVENT_FL_TRACEPOINT; - call->class->reg = trace_event_reg; - call->class->probe = trace_event_raw_event_synth; - call->data = event; - call->tp = event->tp; - - ret = trace_add_event_call(call); - if (ret) { - pr_warn("Failed to register synthetic event: %s\n", - trace_event_name(call)); - goto err; - } - - ret = set_synth_event_print_fmt(call); - if (ret < 0) { - trace_remove_event_call(call); - goto err; - } - out: - return ret; - err: - unregister_trace_event(&call->event); - goto out; -} - -static int unregister_synth_event(struct synth_event *event) -{ - struct trace_event_call *call = &event->call; - int ret; - - ret = trace_remove_event_call(call); - - return ret; -} - -static void free_synth_event(struct synth_event *event) -{ - unsigned int i; - - if (!event) - return; - - for (i = 0; i < event->n_fields; i++) - free_synth_field(event->fields[i]); - - kfree(event->fields); - kfree(event->name); - kfree(event->class.system); - free_synth_tracepoint(event->tp); - free_synth_event_print_fmt(&event->call); - kfree(event); -} - -static struct synth_event *alloc_synth_event(const char *name, int n_fields, - struct synth_field **fields) -{ - struct synth_event *event; - unsigned int i; - - event = kzalloc(sizeof(*event), GFP_KERNEL); - if (!event) { - event = ERR_PTR(-ENOMEM); - goto out; - } - - event->name = kstrdup(name, GFP_KERNEL); - if (!event->name) { - kfree(event); - event = ERR_PTR(-ENOMEM); - goto out; - } - - event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL); - if (!event->fields) { - free_synth_event(event); - event = ERR_PTR(-ENOMEM); - goto out; - } - - dyn_event_init(&event->devent, &synth_event_ops); - - for (i = 0; i < n_fields; i++) - event->fields[i] = fields[i]; - - event->n_fields = n_fields; - out: - return event; -} - -static void action_trace(struct hist_trigger_data *hist_data, - struct tracing_map_elt *elt, void *rec, - struct ring_buffer_event *rbe, void *key, - struct action_data *data, u64 *var_ref_vals) -{ - struct synth_event *event = data->synth_event; - - trace_synth(event, var_ref_vals, data->var_ref_idx); -} - -struct hist_var_data { - struct list_head list; - struct hist_trigger_data *hist_data; -}; - -static int synth_event_check_arg_fn(void *data) -{ - struct dynevent_arg_pair *arg_pair = data; - int size; - - size = synth_field_size((char *)arg_pair->lhs); - - return size ? 0 : -EINVAL; -} - -/** - * synth_event_add_field - Add a new field to a synthetic event cmd - * @cmd: A pointer to the dynevent_cmd struct representing the new event - * @type: The type of the new field to add - * @name: The name of the new field to add - * - * Add a new field to a synthetic event cmd object. Field ordering is in - * the same order the fields are added. - * - * See synth_field_size() for available types. If field_name contains - * [n] the field is considered to be an array. - * - * Return: 0 if successful, error otherwise. - */ -int synth_event_add_field(struct dynevent_cmd *cmd, const char *type, - const char *name) -{ - struct dynevent_arg_pair arg_pair; - int ret; - - if (cmd->type != DYNEVENT_TYPE_SYNTH) - return -EINVAL; - - if (!type || !name) - return -EINVAL; - - dynevent_arg_pair_init(&arg_pair, 0, ';'); - - arg_pair.lhs = type; - arg_pair.rhs = name; - - ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn); - if (ret) - return ret; - - if (++cmd->n_fields > SYNTH_FIELDS_MAX) - ret = -EINVAL; - - return ret; -} -EXPORT_SYMBOL_GPL(synth_event_add_field); - -/** - * synth_event_add_field_str - Add a new field to a synthetic event cmd - * @cmd: A pointer to the dynevent_cmd struct representing the new event - * @type_name: The type and name of the new field to add, as a single string - * - * Add a new field to a synthetic event cmd object, as a single - * string. The @type_name string is expected to be of the form 'type - * name', which will be appended by ';'. No sanity checking is done - - * what's passed in is assumed to already be well-formed. Field - * ordering is in the same order the fields are added. - * - * See synth_field_size() for available types. If field_name contains - * [n] the field is considered to be an array. - * - * Return: 0 if successful, error otherwise. - */ -int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name) -{ - struct dynevent_arg arg; - int ret; - - if (cmd->type != DYNEVENT_TYPE_SYNTH) - return -EINVAL; - - if (!type_name) - return -EINVAL; - - dynevent_arg_init(&arg, ';'); - - arg.str = type_name; - - ret = dynevent_arg_add(cmd, &arg, NULL); - if (ret) - return ret; - - if (++cmd->n_fields > SYNTH_FIELDS_MAX) - ret = -EINVAL; - - return ret; -} -EXPORT_SYMBOL_GPL(synth_event_add_field_str); - -/** - * synth_event_add_fields - Add multiple fields to a synthetic event cmd - * @cmd: A pointer to the dynevent_cmd struct representing the new event - * @fields: An array of type/name field descriptions - * @n_fields: The number of field descriptions contained in the fields array - * - * Add a new set of fields to a synthetic event cmd object. The event - * fields that will be defined for the event should be passed in as an - * array of struct synth_field_desc, and the number of elements in the - * array passed in as n_fields. Field ordering will retain the - * ordering given in the fields array. - * - * See synth_field_size() for available types. If field_name contains - * [n] the field is considered to be an array. - * - * Return: 0 if successful, error otherwise. - */ -int synth_event_add_fields(struct dynevent_cmd *cmd, - struct synth_field_desc *fields, - unsigned int n_fields) -{ - unsigned int i; - int ret = 0; - - for (i = 0; i < n_fields; i++) { - if (fields[i].type == NULL || fields[i].name == NULL) { - ret = -EINVAL; - break; - } - - ret = synth_event_add_field(cmd, fields[i].type, fields[i].name); - if (ret) - break; - } - - return ret; -} -EXPORT_SYMBOL_GPL(synth_event_add_fields); - -/** - * __synth_event_gen_cmd_start - Start a synthetic event command from arg list - * @cmd: A pointer to the dynevent_cmd struct representing the new event - * @name: The name of the synthetic event - * @mod: The module creating the event, NULL if not created from a module - * @args: Variable number of arg (pairs), one pair for each field - * - * NOTE: Users normally won't want to call this function directly, but - * rather use the synth_event_gen_cmd_start() wrapper, which - * automatically adds a NULL to the end of the arg list. If this - * function is used directly, make sure the last arg in the variable - * arg list is NULL. - * - * Generate a synthetic event command to be executed by - * synth_event_gen_cmd_end(). This function can be used to generate - * the complete command or only the first part of it; in the latter - * case, synth_event_add_field(), synth_event_add_field_str(), or - * synth_event_add_fields() can be used to add more fields following - * this. - * - * There should be an even number variable args, each pair consisting - * of a type followed by a field name. - * - * See synth_field_size() for available types. If field_name contains - * [n] the field is considered to be an array. - * - * Return: 0 if successful, error otherwise. - */ -int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name, - struct module *mod, ...) -{ - struct dynevent_arg arg; - va_list args; - int ret; - - cmd->event_name = name; - cmd->private_data = mod; - - if (cmd->type != DYNEVENT_TYPE_SYNTH) - return -EINVAL; - - dynevent_arg_init(&arg, 0); - arg.str = name; - ret = dynevent_arg_add(cmd, &arg, NULL); - if (ret) - return ret; - - va_start(args, mod); - for (;;) { - const char *type, *name; - - type = va_arg(args, const char *); - if (!type) - break; - name = va_arg(args, const char *); - if (!name) - break; - - if (++cmd->n_fields > SYNTH_FIELDS_MAX) { - ret = -EINVAL; - break; - } - - ret = synth_event_add_field(cmd, type, name); - if (ret) - break; - } - va_end(args); - - return ret; -} -EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start); - -/** - * synth_event_gen_cmd_array_start - Start synthetic event command from an array - * @cmd: A pointer to the dynevent_cmd struct representing the new event - * @name: The name of the synthetic event - * @fields: An array of type/name field descriptions - * @n_fields: The number of field descriptions contained in the fields array - * - * Generate a synthetic event command to be executed by - * synth_event_gen_cmd_end(). This function can be used to generate - * the complete command or only the first part of it; in the latter - * case, synth_event_add_field(), synth_event_add_field_str(), or - * synth_event_add_fields() can be used to add more fields following - * this. - * - * The event fields that will be defined for the event should be - * passed in as an array of struct synth_field_desc, and the number of - * elements in the array passed in as n_fields. Field ordering will - * retain the ordering given in the fields array. - * - * See synth_field_size() for available types. If field_name contains - * [n] the field is considered to be an array. - * - * Return: 0 if successful, error otherwise. - */ -int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name, - struct module *mod, - struct synth_field_desc *fields, - unsigned int n_fields) -{ - struct dynevent_arg arg; - unsigned int i; - int ret = 0; - - cmd->event_name = name; - cmd->private_data = mod; - - if (cmd->type != DYNEVENT_TYPE_SYNTH) - return -EINVAL; - - if (n_fields > SYNTH_FIELDS_MAX) - return -EINVAL; - - dynevent_arg_init(&arg, 0); - arg.str = name; - ret = dynevent_arg_add(cmd, &arg, NULL); - if (ret) - return ret; - - for (i = 0; i < n_fields; i++) { - if (fields[i].type == NULL || fields[i].name == NULL) - return -EINVAL; - - ret = synth_event_add_field(cmd, fields[i].type, fields[i].name); - if (ret) - break; - } - - return ret; -} -EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start); - -static int __create_synth_event(int argc, const char *name, const char **argv) -{ - struct synth_field *field, *fields[SYNTH_FIELDS_MAX]; - struct synth_event *event = NULL; - int i, consumed = 0, n_fields = 0, ret = 0; - - /* - * Argument syntax: - * - Add synthetic event: field[;field] ... - * - Remove synthetic event: ! field[;field] ... - * where 'field' = type field_name - */ - - if (name[0] == '\0' || argc < 1) - return -EINVAL; - - mutex_lock(&event_mutex); - - event = find_synth_event(name); - if (event) { - ret = -EEXIST; - goto out; - } - - for (i = 0; i < argc - 1; i++) { - if (strcmp(argv[i], ";") == 0) - continue; - if (n_fields == SYNTH_FIELDS_MAX) { - ret = -EINVAL; - goto err; - } - - field = parse_synth_field(argc - i, &argv[i], &consumed); - if (IS_ERR(field)) { - ret = PTR_ERR(field); - goto err; - } - fields[n_fields++] = field; - i += consumed - 1; - } - - if (i < argc && strcmp(argv[i], ";") != 0) { - ret = -EINVAL; - goto err; - } - - event = alloc_synth_event(name, n_fields, fields); - if (IS_ERR(event)) { - ret = PTR_ERR(event); - event = NULL; - goto err; - } - ret = register_synth_event(event); - if (!ret) - dyn_event_add(&event->devent); - else - free_synth_event(event); - out: - mutex_unlock(&event_mutex); - - return ret; - err: - for (i = 0; i < n_fields; i++) - free_synth_field(fields[i]); - - goto out; -} - -/** - * synth_event_create - Create a new synthetic event - * @name: The name of the new sythetic event - * @fields: An array of type/name field descriptions - * @n_fields: The number of field descriptions contained in the fields array - * @mod: The module creating the event, NULL if not created from a module - * - * Create a new synthetic event with the given name under the - * trace/events/synthetic/ directory. The event fields that will be - * defined for the event should be passed in as an array of struct - * synth_field_desc, and the number elements in the array passed in as - * n_fields. Field ordering will retain the ordering given in the - * fields array. - * - * If the new synthetic event is being created from a module, the mod - * param must be non-NULL. This will ensure that the trace buffer - * won't contain unreadable events. - * - * The new synth event should be deleted using synth_event_delete() - * function. The new synthetic event can be generated from modules or - * other kernel code using trace_synth_event() and related functions. - * - * Return: 0 if successful, error otherwise. - */ -int synth_event_create(const char *name, struct synth_field_desc *fields, - unsigned int n_fields, struct module *mod) -{ - struct dynevent_cmd cmd; - char *buf; - int ret; - - buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL); - if (!buf) - return -ENOMEM; - - synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); - - ret = synth_event_gen_cmd_array_start(&cmd, name, mod, - fields, n_fields); - if (ret) - goto out; - - ret = synth_event_gen_cmd_end(&cmd); - out: - kfree(buf); - - return ret; -} -EXPORT_SYMBOL_GPL(synth_event_create); - -static int destroy_synth_event(struct synth_event *se) -{ - int ret; - - if (se->ref) - ret = -EBUSY; - else { - ret = unregister_synth_event(se); - if (!ret) { - dyn_event_remove(&se->devent); - free_synth_event(se); - } - } - - return ret; -} - -/** - * synth_event_delete - Delete a synthetic event - * @event_name: The name of the new sythetic event - * - * Delete a synthetic event that was created with synth_event_create(). - * - * Return: 0 if successful, error otherwise. - */ -int synth_event_delete(const char *event_name) -{ - struct synth_event *se = NULL; - struct module *mod = NULL; - int ret = -ENOENT; - - mutex_lock(&event_mutex); - se = find_synth_event(event_name); - if (se) { - mod = se->mod; - ret = destroy_synth_event(se); - } - mutex_unlock(&event_mutex); - - if (mod) { - mutex_lock(&trace_types_lock); - /* - * It is safest to reset the ring buffer if the module - * being unloaded registered any events that were - * used. The only worry is if a new module gets - * loaded, and takes on the same id as the events of - * this module. When printing out the buffer, traced - * events left over from this module may be passed to - * the new module events and unexpected results may - * occur. - */ - tracing_reset_all_online_cpus(); - mutex_unlock(&trace_types_lock); - } - - return ret; -} -EXPORT_SYMBOL_GPL(synth_event_delete); - -static int create_or_delete_synth_event(int argc, char **argv) -{ - const char *name = argv[0]; - int ret; - - /* trace_run_command() ensures argc != 0 */ - if (name[0] == '!') { - ret = synth_event_delete(name + 1); - return ret; - } - - ret = __create_synth_event(argc - 1, name, (const char **)argv + 1); - return ret == -ECANCELED ? -EINVAL : ret; -} - -static int synth_event_run_command(struct dynevent_cmd *cmd) -{ - struct synth_event *se; - int ret; - - ret = trace_run_command(cmd->seq.buffer, create_or_delete_synth_event); - if (ret) - return ret; - - se = find_synth_event(cmd->event_name); - if (WARN_ON(!se)) - return -ENOENT; - - se->mod = cmd->private_data; - - return ret; -} - -/** - * synth_event_cmd_init - Initialize a synthetic event command object - * @cmd: A pointer to the dynevent_cmd struct representing the new event - * @buf: A pointer to the buffer used to build the command - * @maxlen: The length of the buffer passed in @buf - * - * Initialize a synthetic event command object. Use this before - * calling any of the other dyenvent_cmd functions. - */ -void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen) -{ - dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH, - synth_event_run_command); -} -EXPORT_SYMBOL_GPL(synth_event_cmd_init); - -static inline int -__synth_event_trace_start(struct trace_event_file *file, - struct synth_event_trace_state *trace_state) -{ - int entry_size, fields_size = 0; - int ret = 0; - - memset(trace_state, '\0', sizeof(*trace_state)); - - /* - * Normal event tracing doesn't get called at all unless the - * ENABLED bit is set (which attaches the probe thus allowing - * this code to be called, etc). Because this is called - * directly by the user, we don't have that but we still need - * to honor not logging when disabled. For the the iterated - * trace case, we save the enabed state upon start and just - * ignore the following data calls. - */ - if (!(file->flags & EVENT_FILE_FL_ENABLED) || - trace_trigger_soft_disabled(file)) { - trace_state->disabled = true; - goto out; - } - - trace_state->event = file->event_call->data; - - fields_size = trace_state->event->n_u64 * sizeof(u64); - - /* - * Avoid ring buffer recursion detection, as this event - * is being performed within another event. - */ - trace_state->buffer = file->tr->array_buffer.buffer; - ring_buffer_nest_start(trace_state->buffer); - - entry_size = sizeof(*trace_state->entry) + fields_size; - trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer, - file, - entry_size); - if (!trace_state->entry) { - ring_buffer_nest_end(trace_state->buffer); - ret = -EINVAL; - } -out: - return ret; -} - -static inline void -__synth_event_trace_end(struct synth_event_trace_state *trace_state) -{ - trace_event_buffer_commit(&trace_state->fbuffer); - - ring_buffer_nest_end(trace_state->buffer); -} - -/** - * synth_event_trace - Trace a synthetic event - * @file: The trace_event_file representing the synthetic event - * @n_vals: The number of values in vals - * @args: Variable number of args containing the event values - * - * Trace a synthetic event using the values passed in the variable - * argument list. - * - * The argument list should be a list 'n_vals' u64 values. The number - * of vals must match the number of field in the synthetic event, and - * must be in the same order as the synthetic event fields. - * - * All vals should be cast to u64, and string vals are just pointers - * to strings, cast to u64. Strings will be copied into space - * reserved in the event for the string, using these pointers. - * - * Return: 0 on success, err otherwise. - */ -int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...) -{ - struct synth_event_trace_state state; - unsigned int i, n_u64; - va_list args; - int ret; - - ret = __synth_event_trace_start(file, &state); - if (ret || state.disabled) - return ret; - - if (n_vals != state.event->n_fields) { - ret = -EINVAL; - goto out; - } - - va_start(args, n_vals); - for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) { - u64 val; - - val = va_arg(args, u64); - - if (state.event->fields[i]->is_string) { - char *str_val = (char *)(long)val; - char *str_field = (char *)&state.entry->fields[n_u64]; - - strscpy(str_field, str_val, STR_VAR_LEN_MAX); - n_u64 += STR_VAR_LEN_MAX / sizeof(u64); - } else { - struct synth_field *field = state.event->fields[i]; - - switch (field->size) { - case 1: - *(u8 *)&state.entry->fields[n_u64] = (u8)val; - break; - - case 2: - *(u16 *)&state.entry->fields[n_u64] = (u16)val; - break; - - case 4: - *(u32 *)&state.entry->fields[n_u64] = (u32)val; - break; - - default: - state.entry->fields[n_u64] = val; - break; - } - n_u64++; - } - } - va_end(args); -out: - __synth_event_trace_end(&state); - - return ret; -} -EXPORT_SYMBOL_GPL(synth_event_trace); - -/** - * synth_event_trace_array - Trace a synthetic event from an array - * @file: The trace_event_file representing the synthetic event - * @vals: Array of values - * @n_vals: The number of values in vals - * - * Trace a synthetic event using the values passed in as 'vals'. - * - * The 'vals' array is just an array of 'n_vals' u64. The number of - * vals must match the number of field in the synthetic event, and - * must be in the same order as the synthetic event fields. - * - * All vals should be cast to u64, and string vals are just pointers - * to strings, cast to u64. Strings will be copied into space - * reserved in the event for the string, using these pointers. - * - * Return: 0 on success, err otherwise. - */ -int synth_event_trace_array(struct trace_event_file *file, u64 *vals, - unsigned int n_vals) -{ - struct synth_event_trace_state state; - unsigned int i, n_u64; - int ret; - - ret = __synth_event_trace_start(file, &state); - if (ret || state.disabled) - return ret; - - if (n_vals != state.event->n_fields) { - ret = -EINVAL; - goto out; - } - - for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) { - if (state.event->fields[i]->is_string) { - char *str_val = (char *)(long)vals[i]; - char *str_field = (char *)&state.entry->fields[n_u64]; - - strscpy(str_field, str_val, STR_VAR_LEN_MAX); - n_u64 += STR_VAR_LEN_MAX / sizeof(u64); - } else { - struct synth_field *field = state.event->fields[i]; - u64 val = vals[i]; - - switch (field->size) { - case 1: - *(u8 *)&state.entry->fields[n_u64] = (u8)val; - break; - - case 2: - *(u16 *)&state.entry->fields[n_u64] = (u16)val; - break; - - case 4: - *(u32 *)&state.entry->fields[n_u64] = (u32)val; - break; - - default: - state.entry->fields[n_u64] = val; - break; - } - n_u64++; - } - } -out: - __synth_event_trace_end(&state); - - return ret; -} -EXPORT_SYMBOL_GPL(synth_event_trace_array); - -/** - * synth_event_trace_start - Start piecewise synthetic event trace - * @file: The trace_event_file representing the synthetic event - * @trace_state: A pointer to object tracking the piecewise trace state - * - * Start the trace of a synthetic event field-by-field rather than all - * at once. - * - * This function 'opens' an event trace, which means space is reserved - * for the event in the trace buffer, after which the event's - * individual field values can be set through either - * synth_event_add_next_val() or synth_event_add_val(). - * - * A pointer to a trace_state object is passed in, which will keep - * track of the current event trace state until the event trace is - * closed (and the event finally traced) using - * synth_event_trace_end(). - * - * Note that synth_event_trace_end() must be called after all values - * have been added for each event trace, regardless of whether adding - * all field values succeeded or not. - * - * Note also that for a given event trace, all fields must be added - * using either synth_event_add_next_val() or synth_event_add_val() - * but not both together or interleaved. - * - * Return: 0 on success, err otherwise. - */ -int synth_event_trace_start(struct trace_event_file *file, - struct synth_event_trace_state *trace_state) -{ - if (!trace_state) - return -EINVAL; + char *event_system; + } match_data; - return __synth_event_trace_start(file, trace_state); -} -EXPORT_SYMBOL_GPL(synth_event_trace_start); + struct { + /* + * var_str contains the $-unstripped variable + * name referenced by var_ref, and used when + * printing the action. Because var_ref + * creation is deferred to create_actions(), + * we need a per-action way to save it until + * then, thus var_str. + */ + char *var_str; -static int __synth_event_add_val(const char *field_name, u64 val, - struct synth_event_trace_state *trace_state) -{ - struct synth_field *field = NULL; - struct synth_trace_event *entry; - struct synth_event *event; - int i, ret = 0; + /* + * var_ref refers to the variable being + * tracked e.g onmax($var). + */ + struct hist_field *var_ref; - if (!trace_state) { - ret = -EINVAL; - goto out; - } + /* + * track_var contains the 'invisible' tracking + * variable created to keep the current + * e.g. max value. + */ + struct hist_field *track_var; - /* can't mix add_next_synth_val() with add_synth_val() */ - if (field_name) { - if (trace_state->add_next) { - ret = -EINVAL; - goto out; - } - trace_state->add_name = true; - } else { - if (trace_state->add_name) { - ret = -EINVAL; - goto out; - } - trace_state->add_next = true; - } + check_track_val_fn_t check_val; + action_fn_t save_data; + } track_data; + }; +}; - if (trace_state->disabled) - goto out; +struct track_data { + u64 track_val; + bool updated; - event = trace_state->event; - if (trace_state->add_name) { - for (i = 0; i < event->n_fields; i++) { - field = event->fields[i]; - if (strcmp(field->name, field_name) == 0) - break; - } - if (!field) { - ret = -EINVAL; - goto out; - } - } else { - if (trace_state->cur_field >= event->n_fields) { - ret = -EINVAL; - goto out; - } - field = event->fields[trace_state->cur_field++]; - } + unsigned int key_len; + void *key; + struct tracing_map_elt elt; - entry = trace_state->entry; - if (field->is_string) { - char *str_val = (char *)(long)val; - char *str_field; + struct action_data *action_data; + struct hist_trigger_data *hist_data; +}; - if (!str_val) { - ret = -EINVAL; - goto out; - } +struct hist_elt_data { + char *comm; + u64 *var_ref_vals; + char *field_var_str[SYNTH_FIELDS_MAX]; +}; - str_field = (char *)&entry->fields[field->offset]; - strscpy(str_field, str_val, STR_VAR_LEN_MAX); - } else { - switch (field->size) { - case 1: - *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val; - break; +struct snapshot_context { + struct tracing_map_elt *elt; + void *key; +}; - case 2: - *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val; - break; +static void track_data_free(struct track_data *track_data) +{ + struct hist_elt_data *elt_data; - case 4: - *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val; - break; + if (!track_data) + return; - default: - trace_state->entry->fields[field->offset] = val; - break; - } + kfree(track_data->key); + + elt_data = track_data->elt.private_data; + if (elt_data) { + kfree(elt_data->comm); + kfree(elt_data); } - out: - return ret; -} -/** - * synth_event_add_next_val - Add the next field's value to an open synth trace - * @val: The value to set the next field to - * @trace_state: A pointer to object tracking the piecewise trace state - * - * Set the value of the next field in an event that's been opened by - * synth_event_trace_start(). - * - * The val param should be the value cast to u64. If the value points - * to a string, the val param should be a char * cast to u64. - * - * This function assumes all the fields in an event are to be set one - * after another - successive calls to this function are made, one for - * each field, in the order of the fields in the event, until all - * fields have been set. If you'd rather set each field individually - * without regard to ordering, synth_event_add_val() can be used - * instead. - * - * Note however that synth_event_add_next_val() and - * synth_event_add_val() can't be intermixed for a given event trace - - * one or the other but not both can be used at the same time. - * - * Note also that synth_event_trace_end() must be called after all - * values have been added for each event trace, regardless of whether - * adding all field values succeeded or not. - * - * Return: 0 on success, err otherwise. - */ -int synth_event_add_next_val(u64 val, - struct synth_event_trace_state *trace_state) -{ - return __synth_event_add_val(NULL, val, trace_state); + kfree(track_data); } -EXPORT_SYMBOL_GPL(synth_event_add_next_val); -/** - * synth_event_add_val - Add a named field's value to an open synth trace - * @field_name: The name of the synthetic event field value to set - * @val: The value to set the next field to - * @trace_state: A pointer to object tracking the piecewise trace state - * - * Set the value of the named field in an event that's been opened by - * synth_event_trace_start(). - * - * The val param should be the value cast to u64. If the value points - * to a string, the val param should be a char * cast to u64. - * - * This function looks up the field name, and if found, sets the field - * to the specified value. This lookup makes this function more - * expensive than synth_event_add_next_val(), so use that or the - * none-piecewise synth_event_trace() instead if efficiency is more - * important. - * - * Note however that synth_event_add_next_val() and - * synth_event_add_val() can't be intermixed for a given event trace - - * one or the other but not both can be used at the same time. - * - * Note also that synth_event_trace_end() must be called after all - * values have been added for each event trace, regardless of whether - * adding all field values succeeded or not. - * - * Return: 0 on success, err otherwise. - */ -int synth_event_add_val(const char *field_name, u64 val, - struct synth_event_trace_state *trace_state) +static struct track_data *track_data_alloc(unsigned int key_len, + struct action_data *action_data, + struct hist_trigger_data *hist_data) { - return __synth_event_add_val(field_name, val, trace_state); -} -EXPORT_SYMBOL_GPL(synth_event_add_val); + struct track_data *data = kzalloc(sizeof(*data), GFP_KERNEL); + struct hist_elt_data *elt_data; -/** - * synth_event_trace_end - End piecewise synthetic event trace - * @trace_state: A pointer to object tracking the piecewise trace state - * - * End the trace of a synthetic event opened by - * synth_event_trace__start(). - * - * This function 'closes' an event trace, which basically means that - * it commits the reserved event and cleans up other loose ends. - * - * A pointer to a trace_state object is passed in, which will keep - * track of the current event trace state opened with - * synth_event_trace_start(). - * - * Note that this function must be called after all values have been - * added for each event trace, regardless of whether adding all field - * values succeeded or not. - * - * Return: 0 on success, err otherwise. - */ -int synth_event_trace_end(struct synth_event_trace_state *trace_state) -{ - if (!trace_state) - return -EINVAL; + if (!data) + return ERR_PTR(-ENOMEM); - __synth_event_trace_end(trace_state); + data->key = kzalloc(key_len, GFP_KERNEL); + if (!data->key) { + track_data_free(data); + return ERR_PTR(-ENOMEM); + } - return 0; -} -EXPORT_SYMBOL_GPL(synth_event_trace_end); + data->key_len = key_len; + data->action_data = action_data; + data->hist_data = hist_data; -static int create_synth_event(int argc, const char **argv) -{ - const char *name = argv[0]; - int len; + elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL); + if (!elt_data) { + track_data_free(data); + return ERR_PTR(-ENOMEM); + } - if (name[0] != 's' || name[1] != ':') - return -ECANCELED; - name += 2; + data->elt.private_data = elt_data; - /* This interface accepts group name prefix */ - if (strchr(name, '/')) { - len = str_has_prefix(name, SYNTH_SYSTEM "/"); - if (len == 0) - return -EINVAL; - name += len; + elt_data->comm = kzalloc(TASK_COMM_LEN, GFP_KERNEL); + if (!elt_data->comm) { + track_data_free(data); + return ERR_PTR(-ENOMEM); } - return __create_synth_event(argc - 1, name, argv + 1); -} - -static int synth_event_release(struct dyn_event *ev) -{ - struct synth_event *event = to_synth_event(ev); - int ret; - if (event->ref) - return -EBUSY; + return data; +} - ret = unregister_synth_event(event); - if (ret) - return ret; +static char last_cmd[MAX_FILTER_STR_VAL]; +static char last_cmd_loc[MAX_FILTER_STR_VAL]; - dyn_event_remove(ev); - free_synth_event(event); - return 0; +static int errpos(char *str) +{ + return err_pos(last_cmd, str); } -static int __synth_event_show(struct seq_file *m, struct synth_event *event) +static void last_cmd_set(struct trace_event_file *file, char *str) { - struct synth_field *field; - unsigned int i; + const char *system = NULL, *name = NULL; + struct trace_event_call *call; - seq_printf(m, "%s\t", event->name); + if (!str) + return; - for (i = 0; i < event->n_fields; i++) { - field = event->fields[i]; + strcpy(last_cmd, "hist:"); + strncat(last_cmd, str, MAX_FILTER_STR_VAL - 1 - sizeof("hist:")); - /* parameter values */ - seq_printf(m, "%s %s%s", field->type, field->name, - i == event->n_fields - 1 ? "" : "; "); + if (file) { + call = file->event_call; + system = call->class->system; + if (system) { + name = trace_event_name(call); + if (!name) + system = NULL; + } } - seq_putc(m, '\n'); - - return 0; + if (system) + snprintf(last_cmd_loc, MAX_FILTER_STR_VAL, "hist:%s:%s", system, name); } -static int synth_event_show(struct seq_file *m, struct dyn_event *ev) +static void hist_err(struct trace_array *tr, u8 err_type, u8 err_pos) { - struct synth_event *event = to_synth_event(ev); - - seq_printf(m, "s:%s/", event->class.system); - - return __synth_event_show(m, event); + tracing_log_err(tr, last_cmd_loc, last_cmd, err_text, + err_type, err_pos); } -static int synth_events_seq_show(struct seq_file *m, void *v) +static void hist_err_clear(void) { - struct dyn_event *ev = v; - - if (!is_synth_event(ev)) - return 0; - - return __synth_event_show(m, to_synth_event(ev)); + last_cmd[0] = '\0'; + last_cmd_loc[0] = '\0'; } -static const struct seq_operations synth_events_seq_op = { - .start = dyn_event_seq_start, - .next = dyn_event_seq_next, - .stop = dyn_event_seq_stop, - .show = synth_events_seq_show, -}; +typedef void (*synth_probe_func_t) (void *__data, u64 *var_ref_vals, + unsigned int *var_ref_idx); -static int synth_events_open(struct inode *inode, struct file *file) +static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals, + unsigned int *var_ref_idx) { - int ret; + struct tracepoint *tp = event->tp; - ret = security_locked_down(LOCKDOWN_TRACEFS); - if (ret) - return ret; + if (unlikely(atomic_read(&tp->key.enabled) > 0)) { + struct tracepoint_func *probe_func_ptr; + synth_probe_func_t probe_func; + void *__data; - if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { - ret = dyn_events_release_all(&synth_event_ops); - if (ret < 0) - return ret; - } + if (!(cpu_online(raw_smp_processor_id()))) + return; - return seq_open(file, &synth_events_seq_op); + probe_func_ptr = rcu_dereference_sched((tp)->funcs); + if (probe_func_ptr) { + do { + probe_func = probe_func_ptr->func; + __data = probe_func_ptr->data; + probe_func(__data, var_ref_vals, var_ref_idx); + } while ((++probe_func_ptr)->func); + } + } } -static ssize_t synth_events_write(struct file *file, - const char __user *buffer, - size_t count, loff_t *ppos) +static void action_trace(struct hist_trigger_data *hist_data, + struct tracing_map_elt *elt, void *rec, + struct ring_buffer_event *rbe, void *key, + struct action_data *data, u64 *var_ref_vals) { - return trace_parse_run_command(file, buffer, count, ppos, - create_or_delete_synth_event); + struct synth_event *event = data->synth_event; + + trace_synth(event, var_ref_vals, data->var_ref_idx); } -static const struct file_operations synth_events_fops = { - .open = synth_events_open, - .write = synth_events_write, - .read = seq_read, - .llseek = seq_lseek, - .release = seq_release, +struct hist_var_data { + struct list_head list; + struct hist_trigger_data *hist_data; }; static u64 hist_field_timestamp(struct hist_field *hist_field, @@ -7653,37 +5904,3 @@ __init int register_trigger_hist_enable_disable_cmds(void) return ret; } - -static __init int trace_events_hist_init(void) -{ - struct dentry *entry = NULL; - struct dentry *d_tracer; - int err = 0; - - err = dyn_event_register(&synth_event_ops); - if (err) { - pr_warn("Could not register synth_event_ops\n"); - return err; - } - - d_tracer = tracing_init_dentry(); - if (IS_ERR(d_tracer)) { - err = PTR_ERR(d_tracer); - goto err; - } - - entry = tracefs_create_file("synthetic_events", 0644, d_tracer, - NULL, &synth_events_fops); - if (!entry) { - err = -ENODEV; - goto err; - } - - return err; - err: - pr_warn("Could not create tracefs 'synthetic_events' entry\n"); - - return err; -} - -fs_initcall(trace_events_hist_init); diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c new file mode 100644 index 0000000..c6cca0d1 --- /dev/null +++ b/kernel/trace/trace_events_synth.c @@ -0,0 +1,1789 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * trace_events_synth - synthetic trace events + * + * Copyright (C) 2015, 2020 Tom Zanussi + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +/* for gfp flag names */ +#include +#include + +#include "trace_synth.h" + +static int create_synth_event(int argc, const char **argv); +static int synth_event_show(struct seq_file *m, struct dyn_event *ev); +static int synth_event_release(struct dyn_event *ev); +static bool synth_event_is_busy(struct dyn_event *ev); +static bool synth_event_match(const char *system, const char *event, + int argc, const char **argv, struct dyn_event *ev); + +static struct dyn_event_operations synth_event_ops = { + .create = create_synth_event, + .show = synth_event_show, + .is_busy = synth_event_is_busy, + .free = synth_event_release, + .match = synth_event_match, +}; + +static bool is_synth_event(struct dyn_event *ev) +{ + return ev->ops == &synth_event_ops; +} + +static struct synth_event *to_synth_event(struct dyn_event *ev) +{ + return container_of(ev, struct synth_event, devent); +} + +static bool synth_event_is_busy(struct dyn_event *ev) +{ + struct synth_event *event = to_synth_event(ev); + + return event->ref != 0; +} + +static bool synth_event_match(const char *system, const char *event, + int argc, const char **argv, struct dyn_event *ev) +{ + struct synth_event *sev = to_synth_event(ev); + + return strcmp(sev->name, event) == 0 && + (!system || strcmp(system, SYNTH_SYSTEM) == 0); +} + +struct synth_trace_event { + struct trace_entry ent; + u64 fields[]; +}; + +static int synth_event_define_fields(struct trace_event_call *call) +{ + struct synth_trace_event trace; + int offset = offsetof(typeof(trace), fields); + struct synth_event *event = call->data; + unsigned int i, size, n_u64; + char *name, *type; + bool is_signed; + int ret = 0; + + for (i = 0, n_u64 = 0; i < event->n_fields; i++) { + size = event->fields[i]->size; + is_signed = event->fields[i]->is_signed; + type = event->fields[i]->type; + name = event->fields[i]->name; + ret = trace_define_field(call, type, name, offset, size, + is_signed, FILTER_OTHER); + if (ret) + break; + + event->fields[i]->offset = n_u64; + + if (event->fields[i]->is_string) { + offset += STR_VAR_LEN_MAX; + n_u64 += STR_VAR_LEN_MAX / sizeof(u64); + } else { + offset += sizeof(u64); + n_u64++; + } + } + + event->n_u64 = n_u64; + + return ret; +} + +static bool synth_field_signed(char *type) +{ + if (str_has_prefix(type, "u")) + return false; + if (strcmp(type, "gfp_t") == 0) + return false; + + return true; +} + +static int synth_field_is_string(char *type) +{ + if (strstr(type, "char[") != NULL) + return true; + + return false; +} + +static int synth_field_string_size(char *type) +{ + char buf[4], *end, *start; + unsigned int len; + int size, err; + + start = strstr(type, "char["); + if (start == NULL) + return -EINVAL; + start += sizeof("char[") - 1; + + end = strchr(type, ']'); + if (!end || end < start) + return -EINVAL; + + len = end - start; + if (len > 3) + return -EINVAL; + + strncpy(buf, start, len); + buf[len] = '\0'; + + err = kstrtouint(buf, 0, &size); + if (err) + return err; + + if (size > STR_VAR_LEN_MAX) + return -EINVAL; + + return size; +} + +static int synth_field_size(char *type) +{ + int size = 0; + + if (strcmp(type, "s64") == 0) + size = sizeof(s64); + else if (strcmp(type, "u64") == 0) + size = sizeof(u64); + else if (strcmp(type, "s32") == 0) + size = sizeof(s32); + else if (strcmp(type, "u32") == 0) + size = sizeof(u32); + else if (strcmp(type, "s16") == 0) + size = sizeof(s16); + else if (strcmp(type, "u16") == 0) + size = sizeof(u16); + else if (strcmp(type, "s8") == 0) + size = sizeof(s8); + else if (strcmp(type, "u8") == 0) + size = sizeof(u8); + else if (strcmp(type, "char") == 0) + size = sizeof(char); + else if (strcmp(type, "unsigned char") == 0) + size = sizeof(unsigned char); + else if (strcmp(type, "int") == 0) + size = sizeof(int); + else if (strcmp(type, "unsigned int") == 0) + size = sizeof(unsigned int); + else if (strcmp(type, "long") == 0) + size = sizeof(long); + else if (strcmp(type, "unsigned long") == 0) + size = sizeof(unsigned long); + else if (strcmp(type, "pid_t") == 0) + size = sizeof(pid_t); + else if (strcmp(type, "gfp_t") == 0) + size = sizeof(gfp_t); + else if (synth_field_is_string(type)) + size = synth_field_string_size(type); + + return size; +} + +static const char *synth_field_fmt(char *type) +{ + const char *fmt = "%llu"; + + if (strcmp(type, "s64") == 0) + fmt = "%lld"; + else if (strcmp(type, "u64") == 0) + fmt = "%llu"; + else if (strcmp(type, "s32") == 0) + fmt = "%d"; + else if (strcmp(type, "u32") == 0) + fmt = "%u"; + else if (strcmp(type, "s16") == 0) + fmt = "%d"; + else if (strcmp(type, "u16") == 0) + fmt = "%u"; + else if (strcmp(type, "s8") == 0) + fmt = "%d"; + else if (strcmp(type, "u8") == 0) + fmt = "%u"; + else if (strcmp(type, "char") == 0) + fmt = "%d"; + else if (strcmp(type, "unsigned char") == 0) + fmt = "%u"; + else if (strcmp(type, "int") == 0) + fmt = "%d"; + else if (strcmp(type, "unsigned int") == 0) + fmt = "%u"; + else if (strcmp(type, "long") == 0) + fmt = "%ld"; + else if (strcmp(type, "unsigned long") == 0) + fmt = "%lu"; + else if (strcmp(type, "pid_t") == 0) + fmt = "%d"; + else if (strcmp(type, "gfp_t") == 0) + fmt = "%x"; + else if (synth_field_is_string(type)) + fmt = "%s"; + + return fmt; +} + +static void print_synth_event_num_val(struct trace_seq *s, + char *print_fmt, char *name, + int size, u64 val, char *space) +{ + switch (size) { + case 1: + trace_seq_printf(s, print_fmt, name, (u8)val, space); + break; + + case 2: + trace_seq_printf(s, print_fmt, name, (u16)val, space); + break; + + case 4: + trace_seq_printf(s, print_fmt, name, (u32)val, space); + break; + + default: + trace_seq_printf(s, print_fmt, name, val, space); + break; + } +} + +static enum print_line_t print_synth_event(struct trace_iterator *iter, + int flags, + struct trace_event *event) +{ + struct trace_array *tr = iter->tr; + struct trace_seq *s = &iter->seq; + struct synth_trace_event *entry; + struct synth_event *se; + unsigned int i, n_u64; + char print_fmt[32]; + const char *fmt; + + entry = (struct synth_trace_event *)iter->ent; + se = container_of(event, struct synth_event, call.event); + + trace_seq_printf(s, "%s: ", se->name); + + for (i = 0, n_u64 = 0; i < se->n_fields; i++) { + if (trace_seq_has_overflowed(s)) + goto end; + + fmt = synth_field_fmt(se->fields[i]->type); + + /* parameter types */ + if (tr && tr->trace_flags & TRACE_ITER_VERBOSE) + trace_seq_printf(s, "%s ", fmt); + + snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt); + + /* parameter values */ + if (se->fields[i]->is_string) { + trace_seq_printf(s, print_fmt, se->fields[i]->name, + (char *)&entry->fields[n_u64], + i == se->n_fields - 1 ? "" : " "); + n_u64 += STR_VAR_LEN_MAX / sizeof(u64); + } else { + struct trace_print_flags __flags[] = { + __def_gfpflag_names, {-1, NULL} }; + char *space = (i == se->n_fields - 1 ? "" : " "); + + print_synth_event_num_val(s, print_fmt, + se->fields[i]->name, + se->fields[i]->size, + entry->fields[n_u64], + space); + + if (strcmp(se->fields[i]->type, "gfp_t") == 0) { + trace_seq_puts(s, " ("); + trace_print_flags_seq(s, "|", + entry->fields[n_u64], + __flags); + trace_seq_putc(s, ')'); + } + n_u64++; + } + } +end: + trace_seq_putc(s, '\n'); + + return trace_handle_return(s); +} + +static struct trace_event_functions synth_event_funcs = { + .trace = print_synth_event +}; + +static notrace void trace_event_raw_event_synth(void *__data, + u64 *var_ref_vals, + unsigned int *var_ref_idx) +{ + struct trace_event_file *trace_file = __data; + struct synth_trace_event *entry; + struct trace_event_buffer fbuffer; + struct trace_buffer *buffer; + struct synth_event *event; + unsigned int i, n_u64, val_idx; + int fields_size = 0; + + event = trace_file->event_call->data; + + if (trace_trigger_soft_disabled(trace_file)) + return; + + fields_size = event->n_u64 * sizeof(u64); + + /* + * Avoid ring buffer recursion detection, as this event + * is being performed within another event. + */ + buffer = trace_file->tr->array_buffer.buffer; + ring_buffer_nest_start(buffer); + + entry = trace_event_buffer_reserve(&fbuffer, trace_file, + sizeof(*entry) + fields_size); + if (!entry) + goto out; + + for (i = 0, n_u64 = 0; i < event->n_fields; i++) { + val_idx = var_ref_idx[i]; + if (event->fields[i]->is_string) { + char *str_val = (char *)(long)var_ref_vals[val_idx]; + char *str_field = (char *)&entry->fields[n_u64]; + + strscpy(str_field, str_val, STR_VAR_LEN_MAX); + n_u64 += STR_VAR_LEN_MAX / sizeof(u64); + } else { + struct synth_field *field = event->fields[i]; + u64 val = var_ref_vals[val_idx]; + + switch (field->size) { + case 1: + *(u8 *)&entry->fields[n_u64] = (u8)val; + break; + + case 2: + *(u16 *)&entry->fields[n_u64] = (u16)val; + break; + + case 4: + *(u32 *)&entry->fields[n_u64] = (u32)val; + break; + + default: + entry->fields[n_u64] = val; + break; + } + n_u64++; + } + } + + trace_event_buffer_commit(&fbuffer); +out: + ring_buffer_nest_end(buffer); +} + +static void free_synth_event_print_fmt(struct trace_event_call *call) +{ + if (call) { + kfree(call->print_fmt); + call->print_fmt = NULL; + } +} + +static int __set_synth_event_print_fmt(struct synth_event *event, + char *buf, int len) +{ + const char *fmt; + int pos = 0; + int i; + + /* When len=0, we just calculate the needed length */ +#define LEN_OR_ZERO (len ? len - pos : 0) + + pos += snprintf(buf + pos, LEN_OR_ZERO, "\""); + for (i = 0; i < event->n_fields; i++) { + fmt = synth_field_fmt(event->fields[i]->type); + pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s", + event->fields[i]->name, fmt, + i == event->n_fields - 1 ? "" : ", "); + } + pos += snprintf(buf + pos, LEN_OR_ZERO, "\""); + + for (i = 0; i < event->n_fields; i++) { + pos += snprintf(buf + pos, LEN_OR_ZERO, + ", REC->%s", event->fields[i]->name); + } + +#undef LEN_OR_ZERO + + /* return the length of print_fmt */ + return pos; +} + +static int set_synth_event_print_fmt(struct trace_event_call *call) +{ + struct synth_event *event = call->data; + char *print_fmt; + int len; + + /* First: called with 0 length to calculate the needed length */ + len = __set_synth_event_print_fmt(event, NULL, 0); + + print_fmt = kmalloc(len + 1, GFP_KERNEL); + if (!print_fmt) + return -ENOMEM; + + /* Second: actually write the @print_fmt */ + __set_synth_event_print_fmt(event, print_fmt, len + 1); + call->print_fmt = print_fmt; + + return 0; +} + +static void free_synth_field(struct synth_field *field) +{ + kfree(field->type); + kfree(field->name); + kfree(field); +} + +static struct synth_field *parse_synth_field(int argc, const char **argv, + int *consumed) +{ + struct synth_field *field; + const char *prefix = NULL, *field_type = argv[0], *field_name, *array; + int len, ret = 0; + + if (field_type[0] == ';') + field_type++; + + if (!strcmp(field_type, "unsigned")) { + if (argc < 3) + return ERR_PTR(-EINVAL); + prefix = "unsigned "; + field_type = argv[1]; + field_name = argv[2]; + *consumed = 3; + } else { + field_name = argv[1]; + *consumed = 2; + } + + field = kzalloc(sizeof(*field), GFP_KERNEL); + if (!field) + return ERR_PTR(-ENOMEM); + + len = strlen(field_name); + array = strchr(field_name, '['); + if (array) + len -= strlen(array); + else if (field_name[len - 1] == ';') + len--; + + field->name = kmemdup_nul(field_name, len, GFP_KERNEL); + if (!field->name) { + ret = -ENOMEM; + goto free; + } + + if (field_type[0] == ';') + field_type++; + len = strlen(field_type) + 1; + if (array) + len += strlen(array); + if (prefix) + len += strlen(prefix); + + field->type = kzalloc(len, GFP_KERNEL); + if (!field->type) { + ret = -ENOMEM; + goto free; + } + if (prefix) + strcat(field->type, prefix); + strcat(field->type, field_type); + if (array) { + strcat(field->type, array); + if (field->type[len - 1] == ';') + field->type[len - 1] = '\0'; + } + + field->size = synth_field_size(field->type); + if (!field->size) { + ret = -EINVAL; + goto free; + } + + if (synth_field_is_string(field->type)) + field->is_string = true; + + field->is_signed = synth_field_signed(field->type); + + out: + return field; + free: + free_synth_field(field); + field = ERR_PTR(ret); + goto out; +} + +static void free_synth_tracepoint(struct tracepoint *tp) +{ + if (!tp) + return; + + kfree(tp->name); + kfree(tp); +} + +static struct tracepoint *alloc_synth_tracepoint(char *name) +{ + struct tracepoint *tp; + + tp = kzalloc(sizeof(*tp), GFP_KERNEL); + if (!tp) + return ERR_PTR(-ENOMEM); + + tp->name = kstrdup(name, GFP_KERNEL); + if (!tp->name) { + kfree(tp); + return ERR_PTR(-ENOMEM); + } + + return tp; +} + +struct synth_event *find_synth_event(const char *name) +{ + struct dyn_event *pos; + struct synth_event *event; + + for_each_dyn_event(pos) { + if (!is_synth_event(pos)) + continue; + event = to_synth_event(pos); + if (strcmp(event->name, name) == 0) + return event; + } + + return NULL; +} + +static struct trace_event_fields synth_event_fields_array[] = { + { .type = TRACE_FUNCTION_TYPE, + .define_fields = synth_event_define_fields }, + {} +}; + +static int register_synth_event(struct synth_event *event) +{ + struct trace_event_call *call = &event->call; + int ret = 0; + + event->call.class = &event->class; + event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL); + if (!event->class.system) { + ret = -ENOMEM; + goto out; + } + + event->tp = alloc_synth_tracepoint(event->name); + if (IS_ERR(event->tp)) { + ret = PTR_ERR(event->tp); + event->tp = NULL; + goto out; + } + + INIT_LIST_HEAD(&call->class->fields); + call->event.funcs = &synth_event_funcs; + call->class->fields_array = synth_event_fields_array; + + ret = register_trace_event(&call->event); + if (!ret) { + ret = -ENODEV; + goto out; + } + call->flags = TRACE_EVENT_FL_TRACEPOINT; + call->class->reg = trace_event_reg; + call->class->probe = trace_event_raw_event_synth; + call->data = event; + call->tp = event->tp; + + ret = trace_add_event_call(call); + if (ret) { + pr_warn("Failed to register synthetic event: %s\n", + trace_event_name(call)); + goto err; + } + + ret = set_synth_event_print_fmt(call); + if (ret < 0) { + trace_remove_event_call(call); + goto err; + } + out: + return ret; + err: + unregister_trace_event(&call->event); + goto out; +} + +static int unregister_synth_event(struct synth_event *event) +{ + struct trace_event_call *call = &event->call; + int ret; + + ret = trace_remove_event_call(call); + + return ret; +} + +static void free_synth_event(struct synth_event *event) +{ + unsigned int i; + + if (!event) + return; + + for (i = 0; i < event->n_fields; i++) + free_synth_field(event->fields[i]); + + kfree(event->fields); + kfree(event->name); + kfree(event->class.system); + free_synth_tracepoint(event->tp); + free_synth_event_print_fmt(&event->call); + kfree(event); +} + +static struct synth_event *alloc_synth_event(const char *name, int n_fields, + struct synth_field **fields) +{ + struct synth_event *event; + unsigned int i; + + event = kzalloc(sizeof(*event), GFP_KERNEL); + if (!event) { + event = ERR_PTR(-ENOMEM); + goto out; + } + + event->name = kstrdup(name, GFP_KERNEL); + if (!event->name) { + kfree(event); + event = ERR_PTR(-ENOMEM); + goto out; + } + + event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL); + if (!event->fields) { + free_synth_event(event); + event = ERR_PTR(-ENOMEM); + goto out; + } + + dyn_event_init(&event->devent, &synth_event_ops); + + for (i = 0; i < n_fields; i++) + event->fields[i] = fields[i]; + + event->n_fields = n_fields; + out: + return event; +} + +static int synth_event_check_arg_fn(void *data) +{ + struct dynevent_arg_pair *arg_pair = data; + int size; + + size = synth_field_size((char *)arg_pair->lhs); + + return size ? 0 : -EINVAL; +} + +/** + * synth_event_add_field - Add a new field to a synthetic event cmd + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @type: The type of the new field to add + * @name: The name of the new field to add + * + * Add a new field to a synthetic event cmd object. Field ordering is in + * the same order the fields are added. + * + * See synth_field_size() for available types. If field_name contains + * [n] the field is considered to be an array. + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_add_field(struct dynevent_cmd *cmd, const char *type, + const char *name) +{ + struct dynevent_arg_pair arg_pair; + int ret; + + if (cmd->type != DYNEVENT_TYPE_SYNTH) + return -EINVAL; + + if (!type || !name) + return -EINVAL; + + dynevent_arg_pair_init(&arg_pair, 0, ';'); + + arg_pair.lhs = type; + arg_pair.rhs = name; + + ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn); + if (ret) + return ret; + + if (++cmd->n_fields > SYNTH_FIELDS_MAX) + ret = -EINVAL; + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_add_field); + +/** + * synth_event_add_field_str - Add a new field to a synthetic event cmd + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @type_name: The type and name of the new field to add, as a single string + * + * Add a new field to a synthetic event cmd object, as a single + * string. The @type_name string is expected to be of the form 'type + * name', which will be appended by ';'. No sanity checking is done - + * what's passed in is assumed to already be well-formed. Field + * ordering is in the same order the fields are added. + * + * See synth_field_size() for available types. If field_name contains + * [n] the field is considered to be an array. + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name) +{ + struct dynevent_arg arg; + int ret; + + if (cmd->type != DYNEVENT_TYPE_SYNTH) + return -EINVAL; + + if (!type_name) + return -EINVAL; + + dynevent_arg_init(&arg, ';'); + + arg.str = type_name; + + ret = dynevent_arg_add(cmd, &arg, NULL); + if (ret) + return ret; + + if (++cmd->n_fields > SYNTH_FIELDS_MAX) + ret = -EINVAL; + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_add_field_str); + +/** + * synth_event_add_fields - Add multiple fields to a synthetic event cmd + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @fields: An array of type/name field descriptions + * @n_fields: The number of field descriptions contained in the fields array + * + * Add a new set of fields to a synthetic event cmd object. The event + * fields that will be defined for the event should be passed in as an + * array of struct synth_field_desc, and the number of elements in the + * array passed in as n_fields. Field ordering will retain the + * ordering given in the fields array. + * + * See synth_field_size() for available types. If field_name contains + * [n] the field is considered to be an array. + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_add_fields(struct dynevent_cmd *cmd, + struct synth_field_desc *fields, + unsigned int n_fields) +{ + unsigned int i; + int ret = 0; + + for (i = 0; i < n_fields; i++) { + if (fields[i].type == NULL || fields[i].name == NULL) { + ret = -EINVAL; + break; + } + + ret = synth_event_add_field(cmd, fields[i].type, fields[i].name); + if (ret) + break; + } + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_add_fields); + +/** + * __synth_event_gen_cmd_start - Start a synthetic event command from arg list + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @name: The name of the synthetic event + * @mod: The module creating the event, NULL if not created from a module + * @args: Variable number of arg (pairs), one pair for each field + * + * NOTE: Users normally won't want to call this function directly, but + * rather use the synth_event_gen_cmd_start() wrapper, which + * automatically adds a NULL to the end of the arg list. If this + * function is used directly, make sure the last arg in the variable + * arg list is NULL. + * + * Generate a synthetic event command to be executed by + * synth_event_gen_cmd_end(). This function can be used to generate + * the complete command or only the first part of it; in the latter + * case, synth_event_add_field(), synth_event_add_field_str(), or + * synth_event_add_fields() can be used to add more fields following + * this. + * + * There should be an even number variable args, each pair consisting + * of a type followed by a field name. + * + * See synth_field_size() for available types. If field_name contains + * [n] the field is considered to be an array. + * + * Return: 0 if successful, error otherwise. + */ +int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name, + struct module *mod, ...) +{ + struct dynevent_arg arg; + va_list args; + int ret; + + cmd->event_name = name; + cmd->private_data = mod; + + if (cmd->type != DYNEVENT_TYPE_SYNTH) + return -EINVAL; + + dynevent_arg_init(&arg, 0); + arg.str = name; + ret = dynevent_arg_add(cmd, &arg, NULL); + if (ret) + return ret; + + va_start(args, mod); + for (;;) { + const char *type, *name; + + type = va_arg(args, const char *); + if (!type) + break; + name = va_arg(args, const char *); + if (!name) + break; + + if (++cmd->n_fields > SYNTH_FIELDS_MAX) { + ret = -EINVAL; + break; + } + + ret = synth_event_add_field(cmd, type, name); + if (ret) + break; + } + va_end(args); + + return ret; +} +EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start); + +/** + * synth_event_gen_cmd_array_start - Start synthetic event command from an array + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @name: The name of the synthetic event + * @fields: An array of type/name field descriptions + * @n_fields: The number of field descriptions contained in the fields array + * + * Generate a synthetic event command to be executed by + * synth_event_gen_cmd_end(). This function can be used to generate + * the complete command or only the first part of it; in the latter + * case, synth_event_add_field(), synth_event_add_field_str(), or + * synth_event_add_fields() can be used to add more fields following + * this. + * + * The event fields that will be defined for the event should be + * passed in as an array of struct synth_field_desc, and the number of + * elements in the array passed in as n_fields. Field ordering will + * retain the ordering given in the fields array. + * + * See synth_field_size() for available types. If field_name contains + * [n] the field is considered to be an array. + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name, + struct module *mod, + struct synth_field_desc *fields, + unsigned int n_fields) +{ + struct dynevent_arg arg; + unsigned int i; + int ret = 0; + + cmd->event_name = name; + cmd->private_data = mod; + + if (cmd->type != DYNEVENT_TYPE_SYNTH) + return -EINVAL; + + if (n_fields > SYNTH_FIELDS_MAX) + return -EINVAL; + + dynevent_arg_init(&arg, 0); + arg.str = name; + ret = dynevent_arg_add(cmd, &arg, NULL); + if (ret) + return ret; + + for (i = 0; i < n_fields; i++) { + if (fields[i].type == NULL || fields[i].name == NULL) + return -EINVAL; + + ret = synth_event_add_field(cmd, fields[i].type, fields[i].name); + if (ret) + break; + } + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start); + +static int __create_synth_event(int argc, const char *name, const char **argv) +{ + struct synth_field *field, *fields[SYNTH_FIELDS_MAX]; + struct synth_event *event = NULL; + int i, consumed = 0, n_fields = 0, ret = 0; + + /* + * Argument syntax: + * - Add synthetic event: field[;field] ... + * - Remove synthetic event: ! field[;field] ... + * where 'field' = type field_name + */ + + if (name[0] == '\0' || argc < 1) + return -EINVAL; + + mutex_lock(&event_mutex); + + event = find_synth_event(name); + if (event) { + ret = -EEXIST; + goto out; + } + + for (i = 0; i < argc - 1; i++) { + if (strcmp(argv[i], ";") == 0) + continue; + if (n_fields == SYNTH_FIELDS_MAX) { + ret = -EINVAL; + goto err; + } + + field = parse_synth_field(argc - i, &argv[i], &consumed); + if (IS_ERR(field)) { + ret = PTR_ERR(field); + goto err; + } + fields[n_fields++] = field; + i += consumed - 1; + } + + if (i < argc && strcmp(argv[i], ";") != 0) { + ret = -EINVAL; + goto err; + } + + event = alloc_synth_event(name, n_fields, fields); + if (IS_ERR(event)) { + ret = PTR_ERR(event); + event = NULL; + goto err; + } + ret = register_synth_event(event); + if (!ret) + dyn_event_add(&event->devent); + else + free_synth_event(event); + out: + mutex_unlock(&event_mutex); + + return ret; + err: + for (i = 0; i < n_fields; i++) + free_synth_field(fields[i]); + + goto out; +} + +/** + * synth_event_create - Create a new synthetic event + * @name: The name of the new sythetic event + * @fields: An array of type/name field descriptions + * @n_fields: The number of field descriptions contained in the fields array + * @mod: The module creating the event, NULL if not created from a module + * + * Create a new synthetic event with the given name under the + * trace/events/synthetic/ directory. The event fields that will be + * defined for the event should be passed in as an array of struct + * synth_field_desc, and the number elements in the array passed in as + * n_fields. Field ordering will retain the ordering given in the + * fields array. + * + * If the new synthetic event is being created from a module, the mod + * param must be non-NULL. This will ensure that the trace buffer + * won't contain unreadable events. + * + * The new synth event should be deleted using synth_event_delete() + * function. The new synthetic event can be generated from modules or + * other kernel code using trace_synth_event() and related functions. + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_create(const char *name, struct synth_field_desc *fields, + unsigned int n_fields, struct module *mod) +{ + struct dynevent_cmd cmd; + char *buf; + int ret; + + buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); + + ret = synth_event_gen_cmd_array_start(&cmd, name, mod, + fields, n_fields); + if (ret) + goto out; + + ret = synth_event_gen_cmd_end(&cmd); + out: + kfree(buf); + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_create); + +static int destroy_synth_event(struct synth_event *se) +{ + int ret; + + if (se->ref) + ret = -EBUSY; + else { + ret = unregister_synth_event(se); + if (!ret) { + dyn_event_remove(&se->devent); + free_synth_event(se); + } + } + + return ret; +} + +/** + * synth_event_delete - Delete a synthetic event + * @event_name: The name of the new sythetic event + * + * Delete a synthetic event that was created with synth_event_create(). + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_delete(const char *event_name) +{ + struct synth_event *se = NULL; + struct module *mod = NULL; + int ret = -ENOENT; + + mutex_lock(&event_mutex); + se = find_synth_event(event_name); + if (se) { + mod = se->mod; + ret = destroy_synth_event(se); + } + mutex_unlock(&event_mutex); + + if (mod) { + mutex_lock(&trace_types_lock); + /* + * It is safest to reset the ring buffer if the module + * being unloaded registered any events that were + * used. The only worry is if a new module gets + * loaded, and takes on the same id as the events of + * this module. When printing out the buffer, traced + * events left over from this module may be passed to + * the new module events and unexpected results may + * occur. + */ + tracing_reset_all_online_cpus(); + mutex_unlock(&trace_types_lock); + } + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_delete); + +static int create_or_delete_synth_event(int argc, char **argv) +{ + const char *name = argv[0]; + int ret; + + /* trace_run_command() ensures argc != 0 */ + if (name[0] == '!') { + ret = synth_event_delete(name + 1); + return ret; + } + + ret = __create_synth_event(argc - 1, name, (const char **)argv + 1); + return ret == -ECANCELED ? -EINVAL : ret; +} + +static int synth_event_run_command(struct dynevent_cmd *cmd) +{ + struct synth_event *se; + int ret; + + ret = trace_run_command(cmd->seq.buffer, create_or_delete_synth_event); + if (ret) + return ret; + + se = find_synth_event(cmd->event_name); + if (WARN_ON(!se)) + return -ENOENT; + + se->mod = cmd->private_data; + + return ret; +} + +/** + * synth_event_cmd_init - Initialize a synthetic event command object + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @buf: A pointer to the buffer used to build the command + * @maxlen: The length of the buffer passed in @buf + * + * Initialize a synthetic event command object. Use this before + * calling any of the other dyenvent_cmd functions. + */ +void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen) +{ + dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH, + synth_event_run_command); +} +EXPORT_SYMBOL_GPL(synth_event_cmd_init); + +static inline int +__synth_event_trace_start(struct trace_event_file *file, + struct synth_event_trace_state *trace_state) +{ + int entry_size, fields_size = 0; + int ret = 0; + + memset(trace_state, '\0', sizeof(*trace_state)); + + /* + * Normal event tracing doesn't get called at all unless the + * ENABLED bit is set (which attaches the probe thus allowing + * this code to be called, etc). Because this is called + * directly by the user, we don't have that but we still need + * to honor not logging when disabled. For the the iterated + * trace case, we save the enabed state upon start and just + * ignore the following data calls. + */ + if (!(file->flags & EVENT_FILE_FL_ENABLED) || + trace_trigger_soft_disabled(file)) { + trace_state->disabled = true; + ret = -ENOENT; + goto out; + } + + trace_state->event = file->event_call->data; + + fields_size = trace_state->event->n_u64 * sizeof(u64); + + /* + * Avoid ring buffer recursion detection, as this event + * is being performed within another event. + */ + trace_state->buffer = file->tr->array_buffer.buffer; + ring_buffer_nest_start(trace_state->buffer); + + entry_size = sizeof(*trace_state->entry) + fields_size; + trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer, + file, + entry_size); + if (!trace_state->entry) { + ring_buffer_nest_end(trace_state->buffer); + ret = -EINVAL; + } +out: + return ret; +} + +static inline void +__synth_event_trace_end(struct synth_event_trace_state *trace_state) +{ + trace_event_buffer_commit(&trace_state->fbuffer); + + ring_buffer_nest_end(trace_state->buffer); +} + +/** + * synth_event_trace - Trace a synthetic event + * @file: The trace_event_file representing the synthetic event + * @n_vals: The number of values in vals + * @args: Variable number of args containing the event values + * + * Trace a synthetic event using the values passed in the variable + * argument list. + * + * The argument list should be a list 'n_vals' u64 values. The number + * of vals must match the number of field in the synthetic event, and + * must be in the same order as the synthetic event fields. + * + * All vals should be cast to u64, and string vals are just pointers + * to strings, cast to u64. Strings will be copied into space + * reserved in the event for the string, using these pointers. + * + * Return: 0 on success, err otherwise. + */ +int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...) +{ + struct synth_event_trace_state state; + unsigned int i, n_u64; + va_list args; + int ret; + + ret = __synth_event_trace_start(file, &state); + if (ret) { + if (ret == -ENOENT) + ret = 0; /* just disabled, not really an error */ + return ret; + } + + if (n_vals != state.event->n_fields) { + ret = -EINVAL; + goto out; + } + + va_start(args, n_vals); + for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) { + u64 val; + + val = va_arg(args, u64); + + if (state.event->fields[i]->is_string) { + char *str_val = (char *)(long)val; + char *str_field = (char *)&state.entry->fields[n_u64]; + + strscpy(str_field, str_val, STR_VAR_LEN_MAX); + n_u64 += STR_VAR_LEN_MAX / sizeof(u64); + } else { + struct synth_field *field = state.event->fields[i]; + + switch (field->size) { + case 1: + *(u8 *)&state.entry->fields[n_u64] = (u8)val; + break; + + case 2: + *(u16 *)&state.entry->fields[n_u64] = (u16)val; + break; + + case 4: + *(u32 *)&state.entry->fields[n_u64] = (u32)val; + break; + + default: + state.entry->fields[n_u64] = val; + break; + } + n_u64++; + } + } + va_end(args); +out: + __synth_event_trace_end(&state); + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_trace); + +/** + * synth_event_trace_array - Trace a synthetic event from an array + * @file: The trace_event_file representing the synthetic event + * @vals: Array of values + * @n_vals: The number of values in vals + * + * Trace a synthetic event using the values passed in as 'vals'. + * + * The 'vals' array is just an array of 'n_vals' u64. The number of + * vals must match the number of field in the synthetic event, and + * must be in the same order as the synthetic event fields. + * + * All vals should be cast to u64, and string vals are just pointers + * to strings, cast to u64. Strings will be copied into space + * reserved in the event for the string, using these pointers. + * + * Return: 0 on success, err otherwise. + */ +int synth_event_trace_array(struct trace_event_file *file, u64 *vals, + unsigned int n_vals) +{ + struct synth_event_trace_state state; + unsigned int i, n_u64; + int ret; + + ret = __synth_event_trace_start(file, &state); + if (ret) { + if (ret == -ENOENT) + ret = 0; /* just disabled, not really an error */ + return ret; + } + + if (n_vals != state.event->n_fields) { + ret = -EINVAL; + goto out; + } + + for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) { + if (state.event->fields[i]->is_string) { + char *str_val = (char *)(long)vals[i]; + char *str_field = (char *)&state.entry->fields[n_u64]; + + strscpy(str_field, str_val, STR_VAR_LEN_MAX); + n_u64 += STR_VAR_LEN_MAX / sizeof(u64); + } else { + struct synth_field *field = state.event->fields[i]; + u64 val = vals[i]; + + switch (field->size) { + case 1: + *(u8 *)&state.entry->fields[n_u64] = (u8)val; + break; + + case 2: + *(u16 *)&state.entry->fields[n_u64] = (u16)val; + break; + + case 4: + *(u32 *)&state.entry->fields[n_u64] = (u32)val; + break; + + default: + state.entry->fields[n_u64] = val; + break; + } + n_u64++; + } + } +out: + __synth_event_trace_end(&state); + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_trace_array); + +/** + * synth_event_trace_start - Start piecewise synthetic event trace + * @file: The trace_event_file representing the synthetic event + * @trace_state: A pointer to object tracking the piecewise trace state + * + * Start the trace of a synthetic event field-by-field rather than all + * at once. + * + * This function 'opens' an event trace, which means space is reserved + * for the event in the trace buffer, after which the event's + * individual field values can be set through either + * synth_event_add_next_val() or synth_event_add_val(). + * + * A pointer to a trace_state object is passed in, which will keep + * track of the current event trace state until the event trace is + * closed (and the event finally traced) using + * synth_event_trace_end(). + * + * Note that synth_event_trace_end() must be called after all values + * have been added for each event trace, regardless of whether adding + * all field values succeeded or not. + * + * Note also that for a given event trace, all fields must be added + * using either synth_event_add_next_val() or synth_event_add_val() + * but not both together or interleaved. + * + * Return: 0 on success, err otherwise. + */ +int synth_event_trace_start(struct trace_event_file *file, + struct synth_event_trace_state *trace_state) +{ + int ret; + + if (!trace_state) + return -EINVAL; + + ret = __synth_event_trace_start(file, trace_state); + if (ret == -ENOENT) + ret = 0; /* just disabled, not really an error */ + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_trace_start); + +static int __synth_event_add_val(const char *field_name, u64 val, + struct synth_event_trace_state *trace_state) +{ + struct synth_field *field = NULL; + struct synth_trace_event *entry; + struct synth_event *event; + int i, ret = 0; + + if (!trace_state) { + ret = -EINVAL; + goto out; + } + + /* can't mix add_next_synth_val() with add_synth_val() */ + if (field_name) { + if (trace_state->add_next) { + ret = -EINVAL; + goto out; + } + trace_state->add_name = true; + } else { + if (trace_state->add_name) { + ret = -EINVAL; + goto out; + } + trace_state->add_next = true; + } + + if (trace_state->disabled) + goto out; + + event = trace_state->event; + if (trace_state->add_name) { + for (i = 0; i < event->n_fields; i++) { + field = event->fields[i]; + if (strcmp(field->name, field_name) == 0) + break; + } + if (!field) { + ret = -EINVAL; + goto out; + } + } else { + if (trace_state->cur_field >= event->n_fields) { + ret = -EINVAL; + goto out; + } + field = event->fields[trace_state->cur_field++]; + } + + entry = trace_state->entry; + if (field->is_string) { + char *str_val = (char *)(long)val; + char *str_field; + + if (!str_val) { + ret = -EINVAL; + goto out; + } + + str_field = (char *)&entry->fields[field->offset]; + strscpy(str_field, str_val, STR_VAR_LEN_MAX); + } else { + switch (field->size) { + case 1: + *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val; + break; + + case 2: + *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val; + break; + + case 4: + *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val; + break; + + default: + trace_state->entry->fields[field->offset] = val; + break; + } + } + out: + return ret; +} + +/** + * synth_event_add_next_val - Add the next field's value to an open synth trace + * @val: The value to set the next field to + * @trace_state: A pointer to object tracking the piecewise trace state + * + * Set the value of the next field in an event that's been opened by + * synth_event_trace_start(). + * + * The val param should be the value cast to u64. If the value points + * to a string, the val param should be a char * cast to u64. + * + * This function assumes all the fields in an event are to be set one + * after another - successive calls to this function are made, one for + * each field, in the order of the fields in the event, until all + * fields have been set. If you'd rather set each field individually + * without regard to ordering, synth_event_add_val() can be used + * instead. + * + * Note however that synth_event_add_next_val() and + * synth_event_add_val() can't be intermixed for a given event trace - + * one or the other but not both can be used at the same time. + * + * Note also that synth_event_trace_end() must be called after all + * values have been added for each event trace, regardless of whether + * adding all field values succeeded or not. + * + * Return: 0 on success, err otherwise. + */ +int synth_event_add_next_val(u64 val, + struct synth_event_trace_state *trace_state) +{ + return __synth_event_add_val(NULL, val, trace_state); +} +EXPORT_SYMBOL_GPL(synth_event_add_next_val); + +/** + * synth_event_add_val - Add a named field's value to an open synth trace + * @field_name: The name of the synthetic event field value to set + * @val: The value to set the next field to + * @trace_state: A pointer to object tracking the piecewise trace state + * + * Set the value of the named field in an event that's been opened by + * synth_event_trace_start(). + * + * The val param should be the value cast to u64. If the value points + * to a string, the val param should be a char * cast to u64. + * + * This function looks up the field name, and if found, sets the field + * to the specified value. This lookup makes this function more + * expensive than synth_event_add_next_val(), so use that or the + * none-piecewise synth_event_trace() instead if efficiency is more + * important. + * + * Note however that synth_event_add_next_val() and + * synth_event_add_val() can't be intermixed for a given event trace - + * one or the other but not both can be used at the same time. + * + * Note also that synth_event_trace_end() must be called after all + * values have been added for each event trace, regardless of whether + * adding all field values succeeded or not. + * + * Return: 0 on success, err otherwise. + */ +int synth_event_add_val(const char *field_name, u64 val, + struct synth_event_trace_state *trace_state) +{ + return __synth_event_add_val(field_name, val, trace_state); +} +EXPORT_SYMBOL_GPL(synth_event_add_val); + +/** + * synth_event_trace_end - End piecewise synthetic event trace + * @trace_state: A pointer to object tracking the piecewise trace state + * + * End the trace of a synthetic event opened by + * synth_event_trace__start(). + * + * This function 'closes' an event trace, which basically means that + * it commits the reserved event and cleans up other loose ends. + * + * A pointer to a trace_state object is passed in, which will keep + * track of the current event trace state opened with + * synth_event_trace_start(). + * + * Note that this function must be called after all values have been + * added for each event trace, regardless of whether adding all field + * values succeeded or not. + * + * Return: 0 on success, err otherwise. + */ +int synth_event_trace_end(struct synth_event_trace_state *trace_state) +{ + if (!trace_state) + return -EINVAL; + + __synth_event_trace_end(trace_state); + + return 0; +} +EXPORT_SYMBOL_GPL(synth_event_trace_end); + +static int create_synth_event(int argc, const char **argv) +{ + const char *name = argv[0]; + int len; + + if (name[0] != 's' || name[1] != ':') + return -ECANCELED; + name += 2; + + /* This interface accepts group name prefix */ + if (strchr(name, '/')) { + len = str_has_prefix(name, SYNTH_SYSTEM "/"); + if (len == 0) + return -EINVAL; + name += len; + } + return __create_synth_event(argc - 1, name, argv + 1); +} + +static int synth_event_release(struct dyn_event *ev) +{ + struct synth_event *event = to_synth_event(ev); + int ret; + + if (event->ref) + return -EBUSY; + + ret = unregister_synth_event(event); + if (ret) + return ret; + + dyn_event_remove(ev); + free_synth_event(event); + return 0; +} + +static int __synth_event_show(struct seq_file *m, struct synth_event *event) +{ + struct synth_field *field; + unsigned int i; + + seq_printf(m, "%s\t", event->name); + + for (i = 0; i < event->n_fields; i++) { + field = event->fields[i]; + + /* parameter values */ + seq_printf(m, "%s %s%s", field->type, field->name, + i == event->n_fields - 1 ? "" : "; "); + } + + seq_putc(m, '\n'); + + return 0; +} + +static int synth_event_show(struct seq_file *m, struct dyn_event *ev) +{ + struct synth_event *event = to_synth_event(ev); + + seq_printf(m, "s:%s/", event->class.system); + + return __synth_event_show(m, event); +} + +static int synth_events_seq_show(struct seq_file *m, void *v) +{ + struct dyn_event *ev = v; + + if (!is_synth_event(ev)) + return 0; + + return __synth_event_show(m, to_synth_event(ev)); +} + +static const struct seq_operations synth_events_seq_op = { + .start = dyn_event_seq_start, + .next = dyn_event_seq_next, + .stop = dyn_event_seq_stop, + .show = synth_events_seq_show, +}; + +static int synth_events_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = security_locked_down(LOCKDOWN_TRACEFS); + if (ret) + return ret; + + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { + ret = dyn_events_release_all(&synth_event_ops); + if (ret < 0) + return ret; + } + + return seq_open(file, &synth_events_seq_op); +} + +static ssize_t synth_events_write(struct file *file, + const char __user *buffer, + size_t count, loff_t *ppos) +{ + return trace_parse_run_command(file, buffer, count, ppos, + create_or_delete_synth_event); +} + +static const struct file_operations synth_events_fops = { + .open = synth_events_open, + .write = synth_events_write, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static __init int trace_events_synth_init(void) +{ + struct dentry *entry = NULL; + struct dentry *d_tracer; + int err = 0; + + err = dyn_event_register(&synth_event_ops); + if (err) { + pr_warn("Could not register synth_event_ops\n"); + return err; + } + + d_tracer = tracing_init_dentry(); + if (IS_ERR(d_tracer)) { + err = PTR_ERR(d_tracer); + goto err; + } + + entry = tracefs_create_file("synthetic_events", 0644, d_tracer, + NULL, &synth_events_fops); + if (!entry) { + err = -ENODEV; + goto err; + } + + return err; + err: + pr_warn("Could not create tracefs 'synthetic_events' entry\n"); + + return err; +} + +fs_initcall(trace_events_synth_init); diff --git a/kernel/trace/trace_synth.h b/kernel/trace/trace_synth.h new file mode 100644 index 0000000..ac35c45 --- /dev/null +++ b/kernel/trace/trace_synth.h @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifndef __TRACE_SYNTH_H +#define __TRACE_SYNTH_H + +#include "trace_dynevent.h" + +#define SYNTH_SYSTEM "synthetic" +#define SYNTH_FIELDS_MAX 32 + +#define STR_VAR_LEN_MAX 32 /* must be multiple of sizeof(u64) */ + +struct synth_field { + char *type; + char *name; + size_t size; + unsigned int offset; + bool is_signed; + bool is_string; +}; + +struct synth_event { + struct dyn_event devent; + int ref; + char *name; + struct synth_field **fields; + unsigned int n_fields; + unsigned int n_u64; + struct trace_event_class class; + struct trace_event_call call; + struct tracepoint *tp; + struct module *mod; +}; + +extern struct synth_event *find_synth_event(const char *name); + +#endif /* __TRACE_SYNTH_H */ -- 2.7.4