diff options
Diffstat (limited to 'kernel/trace/trace_events_hist.c')
| -rw-r--r-- | kernel/trace/trace_events_hist.c | 895 |
1 files changed, 893 insertions, 2 deletions
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 68b9d6d396a6..80d16d33ad5e 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -20,10 +20,16 @@ #include <linux/slab.h> #include <linux/stacktrace.h> #include <linux/rculist.h> +#include <linux/tracefs.h> #include "tracing_map.h" #include "trace.h" +#define SYNTH_SYSTEM "synthetic" +#define SYNTH_FIELDS_MAX 16 + +#define STR_VAR_LEN_MAX 32 /* must be multiple of sizeof(u64) */ + struct hist_field; typedef u64 (*hist_field_fn_t) (struct hist_field *field, @@ -270,6 +276,26 @@ struct hist_trigger_data { unsigned int n_actions; }; +struct synth_field { + char *type; + char *name; + size_t size; + bool is_signed; + bool is_string; +}; + +struct synth_event { + struct list_head list; + 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 action_data; typedef void (*action_fn_t) (struct hist_trigger_data *hist_data, @@ -282,6 +308,790 @@ struct action_data { unsigned int var_ref_idx; }; +static LIST_HEAD(synth_event_list); +static DEFINE_MUTEX(synth_event_mutex); + +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; + + 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 (strncmp(type, "u", 1) == 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 += strlen("char["); + + 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 (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 (synth_field_is_string(type)) + fmt = "%s"; + + return fmt; +} + +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->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 { + trace_seq_printf(s, print_fmt, se->fields[i]->name, + entry->fields[n_u64], + i == se->n_fields - 1 ? "" : " "); + 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 synth_event *event; + unsigned int i, n_u64; + 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); + + entry = trace_event_buffer_reserve(&fbuffer, trace_file, + sizeof(*entry) + fields_size); + if (!entry) + return; + + for (i = 0, n_u64 = 0; i < event->n_fields; i++) { + if (event->fields[i]->is_string) { + char *str_val = (char *)(long)var_ref_vals[var_ref_idx + i]; + char *str_field = (char *)&entry->fields[n_u64]; + + strncpy(str_field, str_val, STR_VAR_LEN_MAX); + n_u64 += STR_VAR_LEN_MAX / sizeof(u64); + } else { + entry->fields[n_u64] = var_ref_vals[var_ref_idx + i]; + n_u64++; + } + } + + trace_event_buffer_commit(&fbuffer); +} + +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(char *field_type, + char *field_name) +{ + struct synth_field *field; + int len, ret = 0; + char *array; + + if (field_type[0] == ';') + field_type++; + + len = strlen(field_name); + if (field_name[len - 1] == ';') + field_name[len - 1] = '\0'; + + field = kzalloc(sizeof(*field), GFP_KERNEL); + if (!field) + return ERR_PTR(-ENOMEM); + + len = strlen(field_type) + 1; + array = strchr(field_name, '['); + if (array) + len += strlen(array); + field->type = kzalloc(len, GFP_KERNEL); + if (!field->type) { + ret = -ENOMEM; + goto free; + } + strcat(field->type, field_type); + if (array) { + strcat(field->type, array); + *array = '\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); + + field->name = kstrdup(field_name, GFP_KERNEL); + if (!field->name) { + ret = -ENOMEM; + goto free; + } + 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 synth_event *event; + + list_for_each_entry(event, &synth_event_list, list) { + if (strcmp(event->name, name) == 0) + return event; + } + + return NULL; +} + +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->define_fields = synth_event_define_fields; + + 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(char *event_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(event_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; + } + + for (i = 0; i < n_fields; i++) + event->fields[i] = fields[i]; + + event->n_fields = n_fields; + out: + return event; +} + +static void add_or_delete_synth_event(struct synth_event *event, int delete) +{ + if (delete) + free_synth_event(event); + else { + mutex_lock(&synth_event_mutex); + if (!find_synth_event(event->name)) + list_add(&event->list, &synth_event_list); + else + free_synth_event(event); + mutex_unlock(&synth_event_mutex); + } +} + +static int create_synth_event(int argc, char **argv) +{ + struct synth_field *field, *fields[SYNTH_FIELDS_MAX]; + struct synth_event *event = NULL; + bool delete_event = false; + int i, n_fields = 0, ret = 0; + char *name; + + mutex_lock(&synth_event_mutex); + + /* + * Argument syntax: + * - Add synthetic event: <event_name> field[;field] ... + * - Remove synthetic event: !<event_name> field[;field] ... + * where 'field' = type field_name + */ + if (argc < 1) { + ret = -EINVAL; + goto out; + } + + name = argv[0]; + if (name[0] == '!') { + delete_event = true; + name++; + } + + event = find_synth_event(name); + if (event) { + if (delete_event) { + if (event->ref) { + event = NULL; + ret = -EBUSY; + goto out; + } + list_del(&event->list); + goto out; + } + event = NULL; + ret = -EEXIST; + goto out; + } else if (delete_event) + goto out; + + if (argc < 2) { + ret = -EINVAL; + goto out; + } + + for (i = 1; i < argc - 1; i++) { + if (strcmp(argv[i], ";") == 0) + continue; + if (n_fields == SYNTH_FIELDS_MAX) { + ret = -EINVAL; + goto err; + } + + field = parse_synth_field(argv[i], argv[i + 1]); + if (IS_ERR(field)) { + ret = PTR_ERR(field); + goto err; + } + fields[n_fields] = field; + i++; n_fields++; + } + + if (i < argc) { + ret = -EINVAL; + goto err; + } + + event = alloc_synth_event(name, n_fields, fields); + if (IS_ERR(event)) { + ret = PTR_ERR(event); + event = NULL; + goto err; + } + out: + mutex_unlock(&synth_event_mutex); + + if (event) { + if (delete_event) { + ret = unregister_synth_event(event); + add_or_delete_synth_event(event, !ret); + } else { + ret = register_synth_event(event); + add_or_delete_synth_event(event, ret); + } + } + + return ret; + err: + mutex_unlock(&synth_event_mutex); + + for (i = 0; i < n_fields; i++) + free_synth_field(fields[i]); + free_synth_event(event); + + return ret; +} + +static int release_all_synth_events(void) +{ + struct list_head release_events; + struct synth_event *event, *e; + int ret = 0; + + INIT_LIST_HEAD(&release_events); + + mutex_lock(&synth_event_mutex); + + list_for_each_entry(event, &synth_event_list, list) { + if (event->ref) { + mutex_unlock(&synth_event_mutex); + return -EBUSY; + } + } + + list_splice_init(&event->list, &release_events); + + mutex_unlock(&synth_event_mutex); + + list_for_each_entry_safe(event, e, &release_events, list) { + list_del(&event->list); + + ret = unregister_synth_event(event); + add_or_delete_synth_event(event, !ret); + } + + return ret; +} + + +static void *synth_events_seq_start(struct seq_file *m, loff_t *pos) +{ + mutex_lock(&synth_event_mutex); + + return seq_list_start(&synth_event_list, *pos); +} + +static void *synth_events_seq_next(struct seq_file *m, void *v, loff_t *pos) +{ + return seq_list_next(v, &synth_event_list, pos); +} + +static void synth_events_seq_stop(struct seq_file *m, void *v) +{ + mutex_unlock(&synth_event_mutex); +} + +static int synth_events_seq_show(struct seq_file *m, void *v) +{ + struct synth_field *field; + struct synth_event *event = v; + 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 const struct seq_operations synth_events_seq_op = { + .start = synth_events_seq_start, + .next = synth_events_seq_next, + .stop = synth_events_seq_stop, + .show = synth_events_seq_show +}; + +static int synth_events_open(struct inode *inode, struct file *file) +{ + int ret; + + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { + ret = release_all_synth_events(); + 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_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 u64 hist_field_timestamp(struct hist_field *hist_field, struct tracing_map_elt *elt, struct ring_buffer_event *rbe, @@ -2963,6 +3773,28 @@ static int hist_trigger_enable(struct event_trigger_data *data, return ret; } +static bool have_hist_trigger_match(struct event_trigger_data *data, + struct trace_event_file *file) +{ + struct hist_trigger_data *hist_data = data->private_data; + struct event_trigger_data *test, *named_data = NULL; + bool match = false; + + if (hist_data->attrs->name) + named_data = find_named_trigger(hist_data->attrs->name); + + list_for_each_entry_rcu(test, &file->triggers, list) { + if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) { + if (hist_trigger_match(data, test, named_data, false)) { + match = true; + break; + } + } + } + + return match; +} + static bool hist_trigger_check_refs(struct event_trigger_data *data, struct trace_event_file *file) { @@ -3038,6 +3870,8 @@ static void hist_unreg_all(struct trace_event_file *file) { struct event_trigger_data *test, *n; struct hist_trigger_data *hist_data; + struct synth_event *se; + const char *se_name; if (hist_file_check_refs(file)) return; @@ -3047,6 +3881,14 @@ static void hist_unreg_all(struct trace_event_file *file) hist_data = test->private_data; list_del_rcu(&test->list); trace_event_trigger_enable_disable(file, 0); + + mutex_lock(&synth_event_mutex); + se_name = trace_event_name(file->event_call); + se = find_synth_event(se_name); + if (se) + se->ref--; + mutex_unlock(&synth_event_mutex); + update_cond_flag(file); if (hist_data->enable_timestamps) tracing_set_time_stamp_abs(file->tr, false); @@ -3065,6 +3907,8 @@ static int event_hist_trigger_func(struct event_command *cmd_ops, struct hist_trigger_attrs *attrs; struct event_trigger_ops *trigger_ops; struct hist_trigger_data *hist_data; + struct synth_event *se; + const char *se_name; bool remove = false; char *trigger; int ret = 0; @@ -3095,10 +3939,11 @@ static int event_hist_trigger_func(struct event_command *cmd_ops, trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger); - ret = -ENOMEM; trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL); - if (!trigger_data) + if (!trigger_data) { + ret = -ENOMEM; goto out_free; + } trigger_data->count = -1; trigger_data->ops = trigger_ops; @@ -3117,12 +3962,23 @@ static int event_hist_trigger_func(struct event_command *cmd_ops, } if (remove) { + if (!have_hist_trigger_match(trigger_data, file)) + goto out_free; + if (hist_trigger_check_refs(trigger_data, file)) { ret = -EBUSY; goto out_free; } cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file); + + mutex_lock(&synth_event_mutex); + se_name = trace_event_name(file->event_call); + se = find_synth_event(se_name); + if (se) + se->ref--; + mutex_unlock(&synth_event_mutex); + ret = 0; goto out_free; } @@ -3158,6 +4014,13 @@ enable: if (ret) goto out_unreg; + mutex_lock(&synth_event_mutex); + se_name = trace_event_name(file->event_call); + se = find_synth_event(se_name); + if (se) + se->ref++; + mutex_unlock(&synth_event_mutex); + /* Just return zero, not the number of registered triggers */ ret = 0; out: @@ -3330,3 +4193,31 @@ __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; + + 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); |