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linux/kernel/trace/trace_events.c
Steven Rostedt 6e2fdceffd tracing: Use refcount for trace_event_file reference counter 
Instead of using an atomic counter for the trace_event_file reference
counter, use the refcount interface. It has various checks to make sure
the reference counting is correct, and will warn if it detects an error
(like refcount_inc() on '0').

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240726144208.687cce24@rorschach.local.home
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-07 18:12:46 -04:00

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// SPDX-License-Identifier: GPL-2.0
/*
* event tracer
*
* Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
*
* - Added format output of fields of the trace point.
* This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
*
*/
#define pr_fmt(fmt) fmt
#include <linux/workqueue.h>
#include <linux/security.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/tracefs.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/sort.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <trace/events/sched.h>
#include <trace/syscall.h>
#include <asm/setup.h>
#include "trace_output.h"
#undef TRACE_SYSTEM
#define TRACE_SYSTEM "TRACE_SYSTEM"
DEFINE_MUTEX(event_mutex);
LIST_HEAD(ftrace_events);
static LIST_HEAD(ftrace_generic_fields);
static LIST_HEAD(ftrace_common_fields);
static bool eventdir_initialized;
static LIST_HEAD(module_strings);
struct module_string {
struct list_head next;
struct module *module;
char *str;
};
#define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
static struct kmem_cache *field_cachep;
static struct kmem_cache *file_cachep;
static inline int system_refcount(struct event_subsystem *system)
{
return system->ref_count;
}
static int system_refcount_inc(struct event_subsystem *system)
{
return system->ref_count++;
}
static int system_refcount_dec(struct event_subsystem *system)
{
return --system->ref_count;
}
/* Double loops, do not use break, only goto's work */
#define do_for_each_event_file(tr, file) \
list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
list_for_each_entry(file, &tr->events, list)
#define do_for_each_event_file_safe(tr, file) \
list_for_each_entry(tr, &ftrace_trace_arrays, list) { \
struct trace_event_file *___n; \
list_for_each_entry_safe(file, ___n, &tr->events, list)
#define while_for_each_event_file() \
}
static struct ftrace_event_field *
__find_event_field(struct list_head *head, char *name)
{
struct ftrace_event_field *field;
list_for_each_entry(field, head, link) {
if (!strcmp(field->name, name))
return field;
}
return NULL;
}
struct ftrace_event_field *
trace_find_event_field(struct trace_event_call *call, char *name)
{
struct ftrace_event_field *field;
struct list_head *head;
head = trace_get_fields(call);
field = __find_event_field(head, name);
if (field)
return field;
field = __find_event_field(&ftrace_generic_fields, name);
if (field)
return field;
return __find_event_field(&ftrace_common_fields, name);
}
static int __trace_define_field(struct list_head *head, const char *type,
const char *name, int offset, int size,
int is_signed, int filter_type, int len)
{
struct ftrace_event_field *field;
field = kmem_cache_alloc(field_cachep, GFP_TRACE);
if (!field)
return -ENOMEM;
field->name = name;
field->type = type;
if (filter_type == FILTER_OTHER)
field->filter_type = filter_assign_type(type);
else
field->filter_type = filter_type;
field->offset = offset;
field->size = size;
field->is_signed = is_signed;
field->len = len;
list_add(&field->link, head);
return 0;
}
int trace_define_field(struct trace_event_call *call, const char *type,
const char *name, int offset, int size, int is_signed,
int filter_type)
{
struct list_head *head;
if (WARN_ON(!call->class))
return 0;
head = trace_get_fields(call);
return __trace_define_field(head, type, name, offset, size,
is_signed, filter_type, 0);
}
EXPORT_SYMBOL_GPL(trace_define_field);
static int trace_define_field_ext(struct trace_event_call *call, const char *type,
const char *name, int offset, int size, int is_signed,
int filter_type, int len)
{
struct list_head *head;
if (WARN_ON(!call->class))
return 0;
head = trace_get_fields(call);
return __trace_define_field(head, type, name, offset, size,
is_signed, filter_type, len);
}
#define __generic_field(type, item, filter_type) \
ret = __trace_define_field(&ftrace_generic_fields, #type, \
#item, 0, 0, is_signed_type(type), \
filter_type, 0); \
if (ret) \
return ret;
#define __common_field(type, item) \
ret = __trace_define_field(&ftrace_common_fields, #type, \
"common_" #item, \
offsetof(typeof(ent), item), \
sizeof(ent.item), \
is_signed_type(type), FILTER_OTHER, 0); \
if (ret) \
return ret;
static int trace_define_generic_fields(void)
{
int ret;
__generic_field(int, CPU, FILTER_CPU);
__generic_field(int, cpu, FILTER_CPU);
__generic_field(int, common_cpu, FILTER_CPU);
__generic_field(char *, COMM, FILTER_COMM);
__generic_field(char *, comm, FILTER_COMM);
__generic_field(char *, stacktrace, FILTER_STACKTRACE);
__generic_field(char *, STACKTRACE, FILTER_STACKTRACE);
return ret;
}
static int trace_define_common_fields(void)
{
int ret;
struct trace_entry ent;
__common_field(unsigned short, type);
__common_field(unsigned char, flags);
/* Holds both preempt_count and migrate_disable */
__common_field(unsigned char, preempt_count);
__common_field(int, pid);
return ret;
}
static void trace_destroy_fields(struct trace_event_call *call)
{
struct ftrace_event_field *field, *next;
struct list_head *head;
head = trace_get_fields(call);
list_for_each_entry_safe(field, next, head, link) {
list_del(&field->link);
kmem_cache_free(field_cachep, field);
}
}
/*
* run-time version of trace_event_get_offsets_<call>() that returns the last
* accessible offset of trace fields excluding __dynamic_array bytes
*/
int trace_event_get_offsets(struct trace_event_call *call)
{
struct ftrace_event_field *tail;
struct list_head *head;
head = trace_get_fields(call);
/*
* head->next points to the last field with the largest offset,
* since it was added last by trace_define_field()
*/
tail = list_first_entry(head, struct ftrace_event_field, link);
return tail->offset + tail->size;
}
/*
* Check if the referenced field is an array and return true,
* as arrays are OK to dereference.
*/
static bool test_field(const char *fmt, struct trace_event_call *call)
{
struct trace_event_fields *field = call->class->fields_array;
const char *array_descriptor;
const char *p = fmt;
int len;
if (!(len = str_has_prefix(fmt, "REC->")))
return false;
fmt += len;
for (p = fmt; *p; p++) {
if (!isalnum(*p) && *p != '_')
break;
}
len = p - fmt;
for (; field->type; field++) {
if (strncmp(field->name, fmt, len) ||
field->name[len])
continue;
array_descriptor = strchr(field->type, '[');
/* This is an array and is OK to dereference. */
return array_descriptor != NULL;
}
return false;
}
/*
* Examine the print fmt of the event looking for unsafe dereference
* pointers using %p* that could be recorded in the trace event and
* much later referenced after the pointer was freed. Dereferencing
* pointers are OK, if it is dereferenced into the event itself.
*/
static void test_event_printk(struct trace_event_call *call)
{
u64 dereference_flags = 0;
bool first = true;
const char *fmt, *c, *r, *a;
int parens = 0;
char in_quote = 0;
int start_arg = 0;
int arg = 0;
int i;
fmt = call->print_fmt;
if (!fmt)
return;
for (i = 0; fmt[i]; i++) {
switch (fmt[i]) {
case '\\':
i++;
if (!fmt[i])
return;
continue;
case '"':
case '\'':
/*
* The print fmt starts with a string that
* is processed first to find %p* usage,
* then after the first string, the print fmt
* contains arguments that are used to check
* if the dereferenced %p* usage is safe.
*/
if (first) {
if (fmt[i] == '\'')
continue;
if (in_quote) {
arg = 0;
first = false;
/*
* If there was no %p* uses
* the fmt is OK.
*/
if (!dereference_flags)
return;
}
}
if (in_quote) {
if (in_quote == fmt[i])
in_quote = 0;
} else {
in_quote = fmt[i];
}
continue;
case '%':
if (!first || !in_quote)
continue;
i++;
if (!fmt[i])
return;
switch (fmt[i]) {
case '%':
continue;
case 'p':
/* Find dereferencing fields */
switch (fmt[i + 1]) {
case 'B': case 'R': case 'r':
case 'b': case 'M': case 'm':
case 'I': case 'i': case 'E':
case 'U': case 'V': case 'N':
case 'a': case 'd': case 'D':
case 'g': case 't': case 'C':
case 'O': case 'f':
if (WARN_ONCE(arg == 63,
"Too many args for event: %s",
trace_event_name(call)))
return;
dereference_flags |= 1ULL << arg;
}
break;
default:
{
bool star = false;
int j;
/* Increment arg if %*s exists. */
for (j = 0; fmt[i + j]; j++) {
if (isdigit(fmt[i + j]) ||
fmt[i + j] == '.')
continue;
if (fmt[i + j] == '*') {
star = true;
continue;
}
if ((fmt[i + j] == 's') && star)
arg++;
break;
}
break;
} /* default */
} /* switch */
arg++;
continue;
case '(':
if (in_quote)
continue;
parens++;
continue;
case ')':
if (in_quote)
continue;
parens--;
if (WARN_ONCE(parens < 0,
"Paren mismatch for event: %s\narg='%s'\n%*s",
trace_event_name(call),
fmt + start_arg,
(i - start_arg) + 5, "^"))
return;
continue;
case ',':
if (in_quote || parens)
continue;
i++;
while (isspace(fmt[i]))
i++;
start_arg = i;
if (!(dereference_flags & (1ULL << arg)))
goto next_arg;
/* Find the REC-> in the argument */
c = strchr(fmt + i, ',');
r = strstr(fmt + i, "REC->");
if (r && (!c || r < c)) {
/*
* Addresses of events on the buffer,
* or an array on the buffer is
* OK to dereference.
* There's ways to fool this, but
* this is to catch common mistakes,
* not malicious code.
*/
a = strchr(fmt + i, '&');
if ((a && (a < r)) || test_field(r, call))
dereference_flags &= ~(1ULL << arg);
} else if ((r = strstr(fmt + i, "__get_dynamic_array(")) &&
(!c || r < c)) {
dereference_flags &= ~(1ULL << arg);
} else if ((r = strstr(fmt + i, "__get_sockaddr(")) &&
(!c || r < c)) {
dereference_flags &= ~(1ULL << arg);
}
next_arg:
i--;
arg++;
}
}
/*
* If you triggered the below warning, the trace event reported
* uses an unsafe dereference pointer %p*. As the data stored
* at the trace event time may no longer exist when the trace
* event is printed, dereferencing to the original source is
* unsafe. The source of the dereference must be copied into the
* event itself, and the dereference must access the copy instead.
*/
if (WARN_ON_ONCE(dereference_flags)) {
arg = 1;
while (!(dereference_flags & 1)) {
dereference_flags >>= 1;
arg++;
}
pr_warn("event %s has unsafe dereference of argument %d\n",
trace_event_name(call), arg);
pr_warn("print_fmt: %s\n", fmt);
}
}
int trace_event_raw_init(struct trace_event_call *call)
{
int id;
id = register_trace_event(&call->event);
if (!id)
return -ENODEV;
test_event_printk(call);
return 0;
}
EXPORT_SYMBOL_GPL(trace_event_raw_init);
bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
{
struct trace_array *tr = trace_file->tr;
struct trace_array_cpu *data;
struct trace_pid_list *no_pid_list;
struct trace_pid_list *pid_list;
pid_list = rcu_dereference_raw(tr->filtered_pids);
no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
if (!pid_list && !no_pid_list)
return false;
data = this_cpu_ptr(tr->array_buffer.data);
return data->ignore_pid;
}
EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
struct trace_event_file *trace_file,
unsigned long len)
{
struct trace_event_call *event_call = trace_file->event_call;
if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
trace_event_ignore_this_pid(trace_file))
return NULL;
/*
* If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
* preemption (adding one to the preempt_count). Since we are
* interested in the preempt_count at the time the tracepoint was
* hit, we need to subtract one to offset the increment.
*/
fbuffer->trace_ctx = tracing_gen_ctx_dec();
fbuffer->trace_file = trace_file;
fbuffer->event =
trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
event_call->event.type, len,
fbuffer->trace_ctx);
if (!fbuffer->event)
return NULL;
fbuffer->regs = NULL;
fbuffer->entry = ring_buffer_event_data(fbuffer->event);
return fbuffer->entry;
}
EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
int trace_event_reg(struct trace_event_call *call,
enum trace_reg type, void *data)
{
struct trace_event_file *file = data;
WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
switch (type) {
case TRACE_REG_REGISTER:
return tracepoint_probe_register(call->tp,
call->class->probe,
file);
case TRACE_REG_UNREGISTER:
tracepoint_probe_unregister(call->tp,
call->class->probe,
file);
return 0;
#ifdef CONFIG_PERF_EVENTS
case TRACE_REG_PERF_REGISTER:
return tracepoint_probe_register(call->tp,
call->class->perf_probe,
call);
case TRACE_REG_PERF_UNREGISTER:
tracepoint_probe_unregister(call->tp,
call->class->perf_probe,
call);
return 0;
case TRACE_REG_PERF_OPEN:
case TRACE_REG_PERF_CLOSE:
case TRACE_REG_PERF_ADD:
case TRACE_REG_PERF_DEL:
return 0;
#endif
}
return 0;
}
EXPORT_SYMBOL_GPL(trace_event_reg);
void trace_event_enable_cmd_record(bool enable)
{
struct trace_event_file *file;
struct trace_array *tr;
lockdep_assert_held(&event_mutex);
do_for_each_event_file(tr, file) {
if (!(file->flags & EVENT_FILE_FL_ENABLED))
continue;
if (enable) {
tracing_start_cmdline_record();
set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
} else {
tracing_stop_cmdline_record();
clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
}
} while_for_each_event_file();
}
void trace_event_enable_tgid_record(bool enable)
{
struct trace_event_file *file;
struct trace_array *tr;
lockdep_assert_held(&event_mutex);
do_for_each_event_file(tr, file) {
if (!(file->flags & EVENT_FILE_FL_ENABLED))
continue;
if (enable) {
tracing_start_tgid_record();
set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
} else {
tracing_stop_tgid_record();
clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
&file->flags);
}
} while_for_each_event_file();
}
static int __ftrace_event_enable_disable(struct trace_event_file *file,
int enable, int soft_disable)
{
struct trace_event_call *call = file->event_call;
struct trace_array *tr = file->tr;
int ret = 0;
int disable;
switch (enable) {
case 0:
/*
* When soft_disable is set and enable is cleared, the sm_ref
* reference counter is decremented. If it reaches 0, we want
* to clear the SOFT_DISABLED flag but leave the event in the
* state that it was. That is, if the event was enabled and
* SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
* is set we do not want the event to be enabled before we
* clear the bit.
*
* When soft_disable is not set but the SOFT_MODE flag is,
* we do nothing. Do not disable the tracepoint, otherwise
* "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
*/
if (soft_disable) {
if (atomic_dec_return(&file->sm_ref) > 0)
break;
disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
/* Disable use of trace_buffered_event */
trace_buffered_event_disable();
} else
disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
tracing_stop_cmdline_record();
clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
}
if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
tracing_stop_tgid_record();
clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
}
call->class->reg(call, TRACE_REG_UNREGISTER, file);
}
/* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
if (file->flags & EVENT_FILE_FL_SOFT_MODE)
set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
else
clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
break;
case 1:
/*
* When soft_disable is set and enable is set, we want to
* register the tracepoint for the event, but leave the event
* as is. That means, if the event was already enabled, we do
* nothing (but set SOFT_MODE). If the event is disabled, we
* set SOFT_DISABLED before enabling the event tracepoint, so
* it still seems to be disabled.
*/
if (!soft_disable)
clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
else {
if (atomic_inc_return(&file->sm_ref) > 1)
break;
set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
/* Enable use of trace_buffered_event */
trace_buffered_event_enable();
}
if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
bool cmd = false, tgid = false;
/* Keep the event disabled, when going to SOFT_MODE. */
if (soft_disable)
set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
cmd = true;
tracing_start_cmdline_record();
set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
}
if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
tgid = true;
tracing_start_tgid_record();
set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
}
ret = call->class->reg(call, TRACE_REG_REGISTER, file);
if (ret) {
if (cmd)
tracing_stop_cmdline_record();
if (tgid)
tracing_stop_tgid_record();
pr_info("event trace: Could not enable event "
"%s\n", trace_event_name(call));
break;
}
set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
/* WAS_ENABLED gets set but never cleared. */
set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
}
break;
}
return ret;
}
int trace_event_enable_disable(struct trace_event_file *file,
int enable, int soft_disable)
{
return __ftrace_event_enable_disable(file, enable, soft_disable);
}
static int ftrace_event_enable_disable(struct trace_event_file *file,
int enable)
{
return __ftrace_event_enable_disable(file, enable, 0);
}
static void ftrace_clear_events(struct trace_array *tr)
{
struct trace_event_file *file;
mutex_lock(&event_mutex);
list_for_each_entry(file, &tr->events, list) {
ftrace_event_enable_disable(file, 0);
}
mutex_unlock(&event_mutex);
}
static void
event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
{
struct trace_pid_list *pid_list;
struct trace_array *tr = data;
pid_list = rcu_dereference_raw(tr->filtered_pids);
trace_filter_add_remove_task(pid_list, NULL, task);
pid_list = rcu_dereference_raw(tr->filtered_no_pids);
trace_filter_add_remove_task(pid_list, NULL, task);
}
static void
event_filter_pid_sched_process_fork(void *data,
struct task_struct *self,
struct task_struct *task)
{
struct trace_pid_list *pid_list;
struct trace_array *tr = data;
pid_list = rcu_dereference_sched(tr->filtered_pids);
trace_filter_add_remove_task(pid_list, self, task);
pid_list = rcu_dereference_sched(tr->filtered_no_pids);
trace_filter_add_remove_task(pid_list, self, task);
}
void trace_event_follow_fork(struct trace_array *tr, bool enable)
{
if (enable) {
register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
tr, INT_MIN);
register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
tr, INT_MAX);
} else {
unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
tr);
unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
tr);
}
}
static void
event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
struct task_struct *prev,
struct task_struct *next,
unsigned int prev_state)
{
struct trace_array *tr = data;
struct trace_pid_list *no_pid_list;
struct trace_pid_list *pid_list;
bool ret;
pid_list = rcu_dereference_sched(tr->filtered_pids);
no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
/*
* Sched switch is funny, as we only want to ignore it
* in the notrace case if both prev and next should be ignored.
*/
ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
trace_ignore_this_task(NULL, no_pid_list, next);
this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
(trace_ignore_this_task(pid_list, NULL, prev) &&
trace_ignore_this_task(pid_list, NULL, next)));
}
static void
event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
struct task_struct *prev,
struct task_struct *next,
unsigned int prev_state)
{
struct trace_array *tr = data;
struct trace_pid_list *no_pid_list;
struct trace_pid_list *pid_list;
pid_list = rcu_dereference_sched(tr->filtered_pids);
no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
this_cpu_write(tr->array_buffer.data->ignore_pid,
trace_ignore_this_task(pid_list, no_pid_list, next));
}
static void
event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
{
struct trace_array *tr = data;
struct trace_pid_list *no_pid_list;
struct trace_pid_list *pid_list;
/* Nothing to do if we are already tracing */
if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
return;
pid_list = rcu_dereference_sched(tr->filtered_pids);
no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
this_cpu_write(tr->array_buffer.data->ignore_pid,
trace_ignore_this_task(pid_list, no_pid_list, task));
}
static void
event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
{
struct trace_array *tr = data;
struct trace_pid_list *no_pid_list;
struct trace_pid_list *pid_list;
/* Nothing to do if we are not tracing */
if (this_cpu_read(tr->array_buffer.data->ignore_pid))
return;
pid_list = rcu_dereference_sched(tr->filtered_pids);
no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
/* Set tracing if current is enabled */
this_cpu_write(tr->array_buffer.data->ignore_pid,
trace_ignore_this_task(pid_list, no_pid_list, current));
}
static void unregister_pid_events(struct trace_array *tr)
{
unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
}
static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
{
struct trace_pid_list *pid_list;
struct trace_pid_list *no_pid_list;
struct trace_event_file *file;
int cpu;
pid_list = rcu_dereference_protected(tr->filtered_pids,
lockdep_is_held(&event_mutex));
no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
lockdep_is_held(&event_mutex));
/* Make sure there's something to do */
if (!pid_type_enabled(type, pid_list, no_pid_list))
return;
if (!still_need_pid_events(type, pid_list, no_pid_list)) {
unregister_pid_events(tr);
list_for_each_entry(file, &tr->events, list) {
clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
}
for_each_possible_cpu(cpu)
per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
}
if (type & TRACE_PIDS)
rcu_assign_pointer(tr->filtered_pids, NULL);
if (type & TRACE_NO_PIDS)
rcu_assign_pointer(tr->filtered_no_pids, NULL);
/* Wait till all users are no longer using pid filtering */
tracepoint_synchronize_unregister();
if ((type & TRACE_PIDS) && pid_list)
trace_pid_list_free(pid_list);
if ((type & TRACE_NO_PIDS) && no_pid_list)
trace_pid_list_free(no_pid_list);
}
static void ftrace_clear_event_pids(struct trace_array *tr, int type)
{
mutex_lock(&event_mutex);
__ftrace_clear_event_pids(tr, type);
mutex_unlock(&event_mutex);
}
static void __put_system(struct event_subsystem *system)
{
struct event_filter *filter = system->filter;
WARN_ON_ONCE(system_refcount(system) == 0);
if (system_refcount_dec(system))
return;
list_del(&system->list);
if (filter) {
kfree(filter->filter_string);
kfree(filter);
}
kfree_const(system->name);
kfree(system);
}
static void __get_system(struct event_subsystem *system)
{
WARN_ON_ONCE(system_refcount(system) == 0);
system_refcount_inc(system);
}
static void __get_system_dir(struct trace_subsystem_dir *dir)
{
WARN_ON_ONCE(dir->ref_count == 0);
dir->ref_count++;
__get_system(dir->subsystem);
}
static void __put_system_dir(struct trace_subsystem_dir *dir)
{
WARN_ON_ONCE(dir->ref_count == 0);
/* If the subsystem is about to be freed, the dir must be too */
WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
__put_system(dir->subsystem);
if (!--dir->ref_count)
kfree(dir);
}
static void put_system(struct trace_subsystem_dir *dir)
{
mutex_lock(&event_mutex);
__put_system_dir(dir);
mutex_unlock(&event_mutex);
}
static void remove_subsystem(struct trace_subsystem_dir *dir)
{
if (!dir)
return;
if (!--dir->nr_events) {
eventfs_remove_dir(dir->ei);
list_del(&dir->list);
__put_system_dir(dir);
}
}
void event_file_get(struct trace_event_file *file)
{
refcount_inc(&file->ref);
}
void event_file_put(struct trace_event_file *file)
{
if (WARN_ON_ONCE(!refcount_read(&file->ref))) {
if (file->flags & EVENT_FILE_FL_FREED)
kmem_cache_free(file_cachep, file);
return;
}
if (refcount_dec_and_test(&file->ref)) {
/* Count should only go to zero when it is freed */
if (WARN_ON_ONCE(!(file->flags & EVENT_FILE_FL_FREED)))
return;
kmem_cache_free(file_cachep, file);
}
}
static void remove_event_file_dir(struct trace_event_file *file)
{
eventfs_remove_dir(file->ei);
list_del(&file->list);
remove_subsystem(file->system);
free_event_filter(file->filter);
file->flags |= EVENT_FILE_FL_FREED;
event_file_put(file);
}
/*
* __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
*/
static int
__ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
const char *sub, const char *event, int set)
{
struct trace_event_file *file;
struct trace_event_call *call;
const char *name;
int ret = -EINVAL;
int eret = 0;
list_for_each_entry(file, &tr->events, list) {
call = file->event_call;
name = trace_event_name(call);
if (!name || !call->class || !call->class->reg)
continue;
if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
continue;
if (match &&
strcmp(match, name) != 0 &&
strcmp(match, call->class->system) != 0)
continue;
if (sub && strcmp(sub, call->class->system) != 0)
continue;
if (event && strcmp(event, name) != 0)
continue;
ret = ftrace_event_enable_disable(file, set);
/*
* Save the first error and return that. Some events
* may still have been enabled, but let the user
* know that something went wrong.
*/
if (ret && !eret)
eret = ret;
ret = eret;
}
return ret;
}
static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
const char *sub, const char *event, int set)
{
int ret;
mutex_lock(&event_mutex);
ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
mutex_unlock(&event_mutex);
return ret;
}
int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
{
char *event = NULL, *sub = NULL, *match;
int ret;
if (!tr)
return -ENOENT;
/*
* The buf format can be <subsystem>:<event-name>
* *:<event-name> means any event by that name.
* :<event-name> is the same.
*
* <subsystem>:* means all events in that subsystem
* <subsystem>: means the same.
*
* <name> (no ':') means all events in a subsystem with
* the name <name> or any event that matches <name>
*/
match = strsep(&buf, ":");
if (buf) {
sub = match;
event = buf;
match = NULL;
if (!strlen(sub) || strcmp(sub, "*") == 0)
sub = NULL;
if (!strlen(event) || strcmp(event, "*") == 0)
event = NULL;
}
ret = __ftrace_set_clr_event(tr, match, sub, event, set);
/* Put back the colon to allow this to be called again */
if (buf)
*(buf - 1) = ':';
return ret;
}
/**
* trace_set_clr_event - enable or disable an event
* @system: system name to match (NULL for any system)
* @event: event name to match (NULL for all events, within system)
* @set: 1 to enable, 0 to disable
*
* This is a way for other parts of the kernel to enable or disable
* event recording.
*
* Returns 0 on success, -EINVAL if the parameters do not match any
* registered events.
*/
int trace_set_clr_event(const char *system, const char *event, int set)
{
struct trace_array *tr = top_trace_array();
if (!tr)
return -ENODEV;
return __ftrace_set_clr_event(tr, NULL, system, event, set);
}
EXPORT_SYMBOL_GPL(trace_set_clr_event);
/**
* trace_array_set_clr_event - enable or disable an event for a trace array.
* @tr: concerned trace array.
* @system: system name to match (NULL for any system)
* @event: event name to match (NULL for all events, within system)
* @enable: true to enable, false to disable
*
* This is a way for other parts of the kernel to enable or disable
* event recording.
*
* Returns 0 on success, -EINVAL if the parameters do not match any
* registered events.
*/
int trace_array_set_clr_event(struct trace_array *tr, const char *system,
const char *event, bool enable)
{
int set;
if (!tr)
return -ENOENT;
set = (enable == true) ? 1 : 0;
return __ftrace_set_clr_event(tr, NULL, system, event, set);
}
EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
/* 128 should be much more than enough */
#define EVENT_BUF_SIZE 127
static ssize_t
ftrace_event_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_parser parser;
struct seq_file *m = file->private_data;
struct trace_array *tr = m->private;
ssize_t read, ret;
if (!cnt)
return 0;
ret = tracing_update_buffers(tr);
if (ret < 0)
return ret;
if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
return -ENOMEM;
read = trace_get_user(&parser, ubuf, cnt, ppos);
if (read >= 0 && trace_parser_loaded((&parser))) {
int set = 1;
if (*parser.buffer == '!')
set = 0;
ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
if (ret)
goto out_put;
}
ret = read;
out_put:
trace_parser_put(&parser);
return ret;
}
static void *
t_next(struct seq_file *m, void *v, loff_t *pos)
{
struct trace_event_file *file = v;
struct trace_event_call *call;
struct trace_array *tr = m->private;
(*pos)++;
list_for_each_entry_continue(file, &tr->events, list) {
call = file->event_call;
/*
* The ftrace subsystem is for showing formats only.
* They can not be enabled or disabled via the event files.
*/
if (call->class && call->class->reg &&
!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
return file;
}
return NULL;
}
static void *t_start(struct seq_file *m, loff_t *pos)
{
struct trace_event_file *file;
struct trace_array *tr = m->private;
loff_t l;
mutex_lock(&event_mutex);
file = list_entry(&tr->events, struct trace_event_file, list);
for (l = 0; l <= *pos; ) {
file = t_next(m, file, &l);
if (!file)
break;
}
return file;
}
static void *
s_next(struct seq_file *m, void *v, loff_t *pos)
{
struct trace_event_file *file = v;
struct trace_array *tr = m->private;
(*pos)++;
list_for_each_entry_continue(file, &tr->events, list) {
if (file->flags & EVENT_FILE_FL_ENABLED)
return file;
}
return NULL;
}
static void *s_start(struct seq_file *m, loff_t *pos)
{
struct trace_event_file *file;
struct trace_array *tr = m->private;
loff_t l;
mutex_lock(&event_mutex);
file = list_entry(&tr->events, struct trace_event_file, list);
for (l = 0; l <= *pos; ) {
file = s_next(m, file, &l);
if (!file)
break;
}
return file;
}
static int t_show(struct seq_file *m, void *v)
{
struct trace_event_file *file = v;
struct trace_event_call *call = file->event_call;
if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
seq_printf(m, "%s:", call->class->system);
seq_printf(m, "%s\n", trace_event_name(call));
return 0;
}
static void t_stop(struct seq_file *m, void *p)
{
mutex_unlock(&event_mutex);
}
static void *
__next(struct seq_file *m, void *v, loff_t *pos, int type)
{
struct trace_array *tr = m->private;
struct trace_pid_list *pid_list;
if (type == TRACE_PIDS)
pid_list = rcu_dereference_sched(tr->filtered_pids);
else
pid_list = rcu_dereference_sched(tr->filtered_no_pids);
return trace_pid_next(pid_list, v, pos);
}
static void *
p_next(struct seq_file *m, void *v, loff_t *pos)
{
return __next(m, v, pos, TRACE_PIDS);
}
static void *
np_next(struct seq_file *m, void *v, loff_t *pos)
{
return __next(m, v, pos, TRACE_NO_PIDS);
}
static void *__start(struct seq_file *m, loff_t *pos, int type)
__acquires(RCU)
{
struct trace_pid_list *pid_list;
struct trace_array *tr = m->private;
/*
* Grab the mutex, to keep calls to p_next() having the same
* tr->filtered_pids as p_start() has.
* If we just passed the tr->filtered_pids around, then RCU would
* have been enough, but doing that makes things more complex.
*/
mutex_lock(&event_mutex);
rcu_read_lock_sched();
if (type == TRACE_PIDS)
pid_list = rcu_dereference_sched(tr->filtered_pids);
else
pid_list = rcu_dereference_sched(tr->filtered_no_pids);
if (!pid_list)
return NULL;
return trace_pid_start(pid_list, pos);
}
static void *p_start(struct seq_file *m, loff_t *pos)
__acquires(RCU)
{
return __start(m, pos, TRACE_PIDS);
}
static void *np_start(struct seq_file *m, loff_t *pos)
__acquires(RCU)
{
return __start(m, pos, TRACE_NO_PIDS);
}
static void p_stop(struct seq_file *m, void *p)
__releases(RCU)
{
rcu_read_unlock_sched();
mutex_unlock(&event_mutex);
}
static ssize_t
event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct trace_event_file *file;
unsigned long flags;
char buf[4] = "0";
mutex_lock(&event_mutex);
file = event_file_file(filp);
if (likely(file))
flags = file->flags;
mutex_unlock(&event_mutex);
if (!file)
return -ENODEV;
if (flags & EVENT_FILE_FL_ENABLED &&
!(flags & EVENT_FILE_FL_SOFT_DISABLED))
strcpy(buf, "1");
if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
flags & EVENT_FILE_FL_SOFT_MODE)
strcat(buf, "*");
strcat(buf, "\n");
return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
}
static ssize_t
event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct trace_event_file *file;
unsigned long val;
int ret;
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
switch (val) {
case 0:
case 1:
ret = -ENODEV;
mutex_lock(&event_mutex);
file = event_file_file(filp);
if (likely(file)) {
ret = tracing_update_buffers(file->tr);
if (ret < 0) {
mutex_unlock(&event_mutex);
return ret;
}
ret = ftrace_event_enable_disable(file, val);
}
mutex_unlock(&event_mutex);
break;
default:
return -EINVAL;
}
*ppos += cnt;
return ret ? ret : cnt;
}
static ssize_t
system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
const char set_to_char[4] = { '?', '0', '1', 'X' };
struct trace_subsystem_dir *dir = filp->private_data;
struct event_subsystem *system = dir->subsystem;
struct trace_event_call *call;
struct trace_event_file *file;
struct trace_array *tr = dir->tr;
char buf[2];
int set = 0;
int ret;
mutex_lock(&event_mutex);
list_for_each_entry(file, &tr->events, list) {
call = file->event_call;
if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
!trace_event_name(call) || !call->class || !call->class->reg)
continue;
if (system && strcmp(call->class->system, system->name) != 0)
continue;
/*
* We need to find out if all the events are set
* or if all events or cleared, or if we have
* a mixture.
*/
set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
/*
* If we have a mixture, no need to look further.
*/
if (set == 3)
break;
}
mutex_unlock(&event_mutex);
buf[0] = set_to_char[set];
buf[1] = '\n';
ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
return ret;
}
static ssize_t
system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct trace_subsystem_dir *dir = filp->private_data;
struct event_subsystem *system = dir->subsystem;
const char *name = NULL;
unsigned long val;
ssize_t ret;
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
ret = tracing_update_buffers(dir->tr);
if (ret < 0)
return ret;
if (val != 0 && val != 1)
return -EINVAL;
/*
* Opening of "enable" adds a ref count to system,
* so the name is safe to use.
*/
if (system)
name = system->name;
ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
if (ret)
goto out;
ret = cnt;
out:
*ppos += cnt;
return ret;
}
enum {
FORMAT_HEADER = 1,
FORMAT_FIELD_SEPERATOR = 2,
FORMAT_PRINTFMT = 3,
};
static void *f_next(struct seq_file *m, void *v, loff_t *pos)
{
struct trace_event_file *file = event_file_data(m->private);
struct trace_event_call *call = file->event_call;
struct list_head *common_head = &ftrace_common_fields;
struct list_head *head = trace_get_fields(call);
struct list_head *node = v;
(*pos)++;
switch ((unsigned long)v) {
case FORMAT_HEADER:
node = common_head;
break;
case FORMAT_FIELD_SEPERATOR:
node = head;
break;
case FORMAT_PRINTFMT:
/* all done */
return NULL;
}
node = node->prev;
if (node == common_head)
return (void *)FORMAT_FIELD_SEPERATOR;
else if (node == head)
return (void *)FORMAT_PRINTFMT;
else
return node;
}
static int f_show(struct seq_file *m, void *v)
{
struct trace_event_file *file = event_file_data(m->private);
struct trace_event_call *call = file->event_call;
struct ftrace_event_field *field;
const char *array_descriptor;
switch ((unsigned long)v) {
case FORMAT_HEADER:
seq_printf(m, "name: %s\n", trace_event_name(call));
seq_printf(m, "ID: %d\n", call->event.type);
seq_puts(m, "format:\n");
return 0;
case FORMAT_FIELD_SEPERATOR:
seq_putc(m, '\n');
return 0;
case FORMAT_PRINTFMT:
seq_printf(m, "\nprint fmt: %s\n",
call->print_fmt);
return 0;
}
field = list_entry(v, struct ftrace_event_field, link);
/*
* Smartly shows the array type(except dynamic array).
* Normal:
* field:TYPE VAR
* If TYPE := TYPE[LEN], it is shown:
* field:TYPE VAR[LEN]
*/
array_descriptor = strchr(field->type, '[');
if (str_has_prefix(field->type, "__data_loc"))
array_descriptor = NULL;
if (!array_descriptor)
seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
field->type, field->name, field->offset,
field->size, !!field->is_signed);
else if (field->len)
seq_printf(m, "\tfield:%.*s %s[%d];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
(int)(array_descriptor - field->type),
field->type, field->name,
field->len, field->offset,
field->size, !!field->is_signed);
else
seq_printf(m, "\tfield:%.*s %s[];\toffset:%u;\tsize:%u;\tsigned:%d;\n",
(int)(array_descriptor - field->type),
field->type, field->name,
field->offset, field->size, !!field->is_signed);
return 0;
}
static void *f_start(struct seq_file *m, loff_t *pos)
{
struct trace_event_file *file;
void *p = (void *)FORMAT_HEADER;
loff_t l = 0;
/* ->stop() is called even if ->start() fails */
mutex_lock(&event_mutex);
file = event_file_file(m->private);
if (!file)
return ERR_PTR(-ENODEV);
while (l < *pos && p)
p = f_next(m, p, &l);
return p;
}
static void f_stop(struct seq_file *m, void *p)
{
mutex_unlock(&event_mutex);
}
static const struct seq_operations trace_format_seq_ops = {
.start = f_start,
.next = f_next,
.stop = f_stop,
.show = f_show,
};
static int trace_format_open(struct inode *inode, struct file *file)
{
struct seq_file *m;
int ret;
/* Do we want to hide event format files on tracefs lockdown? */
ret = seq_open(file, &trace_format_seq_ops);
if (ret < 0)
return ret;
m = file->private_data;
m->private = file;
return 0;
}
#ifdef CONFIG_PERF_EVENTS
static ssize_t
event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
{
int id = (long)event_file_data(filp);
char buf[32];
int len;
if (unlikely(!id))
return -ENODEV;
len = sprintf(buf, "%d\n", id);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
}
#endif
static ssize_t
event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct trace_event_file *file;
struct trace_seq *s;
int r = -ENODEV;
if (*ppos)
return 0;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
mutex_lock(&event_mutex);
file = event_file_file(filp);
if (file)
print_event_filter(file, s);
mutex_unlock(&event_mutex);
if (file)
r = simple_read_from_buffer(ubuf, cnt, ppos,
s->buffer, trace_seq_used(s));
kfree(s);
return r;
}
static ssize_t
event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct trace_event_file *file;
char *buf;
int err = -ENODEV;
if (cnt >= PAGE_SIZE)
return -EINVAL;
buf = memdup_user_nul(ubuf, cnt);
if (IS_ERR(buf))
return PTR_ERR(buf);
mutex_lock(&event_mutex);
file = event_file_file(filp);
if (file) {
if (file->flags & EVENT_FILE_FL_FREED)
err = -ENODEV;
else
err = apply_event_filter(file, buf);
}
mutex_unlock(&event_mutex);
kfree(buf);
if (err < 0)
return err;
*ppos += cnt;
return cnt;
}
static LIST_HEAD(event_subsystems);
static int subsystem_open(struct inode *inode, struct file *filp)
{
struct trace_subsystem_dir *dir = NULL, *iter_dir;
struct trace_array *tr = NULL, *iter_tr;
struct event_subsystem *system = NULL;
int ret;
if (tracing_is_disabled())
return -ENODEV;
/* Make sure the system still exists */
mutex_lock(&event_mutex);
mutex_lock(&trace_types_lock);
list_for_each_entry(iter_tr, &ftrace_trace_arrays, list) {
list_for_each_entry(iter_dir, &iter_tr->systems, list) {
if (iter_dir == inode->i_private) {
/* Don't open systems with no events */
tr = iter_tr;
dir = iter_dir;
if (dir->nr_events) {
__get_system_dir(dir);
system = dir->subsystem;
}
goto exit_loop;
}
}
}
exit_loop:
mutex_unlock(&trace_types_lock);
mutex_unlock(&event_mutex);
if (!system)
return -ENODEV;
/* Still need to increment the ref count of the system */
if (trace_array_get(tr) < 0) {
put_system(dir);
return -ENODEV;
}
ret = tracing_open_generic(inode, filp);
if (ret < 0) {
trace_array_put(tr);
put_system(dir);
}
return ret;
}
static int system_tr_open(struct inode *inode, struct file *filp)
{
struct trace_subsystem_dir *dir;
struct trace_array *tr = inode->i_private;
int ret;
/* Make a temporary dir that has no system but points to tr */
dir = kzalloc(sizeof(*dir), GFP_KERNEL);
if (!dir)
return -ENOMEM;
ret = tracing_open_generic_tr(inode, filp);
if (ret < 0) {
kfree(dir);
return ret;
}
dir->tr = tr;
filp->private_data = dir;
return 0;
}
static int subsystem_release(struct inode *inode, struct file *file)
{
struct trace_subsystem_dir *dir = file->private_data;
trace_array_put(dir->tr);
/*
* If dir->subsystem is NULL, then this is a temporary
* descriptor that was made for a trace_array to enable
* all subsystems.
*/
if (dir->subsystem)
put_system(dir);
else
kfree(dir);
return 0;
}
static ssize_t
subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct trace_subsystem_dir *dir = filp->private_data;
struct event_subsystem *system = dir->subsystem;
struct trace_seq *s;
int r;
if (*ppos)
return 0;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
print_subsystem_event_filter(system, s);
r = simple_read_from_buffer(ubuf, cnt, ppos,
s->buffer, trace_seq_used(s));
kfree(s);
return r;
}
static ssize_t
subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
{
struct trace_subsystem_dir *dir = filp->private_data;
char *buf;
int err;
if (cnt >= PAGE_SIZE)
return -EINVAL;
buf = memdup_user_nul(ubuf, cnt);
if (IS_ERR(buf))
return PTR_ERR(buf);
err = apply_subsystem_event_filter(dir, buf);
kfree(buf);
if (err < 0)
return err;
*ppos += cnt;
return cnt;
}
static ssize_t
show_header_page_file(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
{
struct trace_array *tr = filp->private_data;
struct trace_seq *s;
int r;
if (*ppos)
return 0;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
ring_buffer_print_page_header(tr->array_buffer.buffer, s);
r = simple_read_from_buffer(ubuf, cnt, ppos,
s->buffer, trace_seq_used(s));
kfree(s);
return r;
}
static ssize_t
show_header_event_file(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
{
struct trace_seq *s;
int r;
if (*ppos)
return 0;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return -ENOMEM;
trace_seq_init(s);
ring_buffer_print_entry_header(s);
r = simple_read_from_buffer(ubuf, cnt, ppos,
s->buffer, trace_seq_used(s));
kfree(s);
return r;
}
static void ignore_task_cpu(void *data)
{
struct trace_array *tr = data;
struct trace_pid_list *pid_list;
struct trace_pid_list *no_pid_list;
/*
* This function is called by on_each_cpu() while the
* event_mutex is held.
*/
pid_list = rcu_dereference_protected(tr->filtered_pids,
mutex_is_locked(&event_mutex));
no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
mutex_is_locked(&event_mutex));
this_cpu_write(tr->array_buffer.data->ignore_pid,
trace_ignore_this_task(pid_list, no_pid_list, current));
}
static void register_pid_events(struct trace_array *tr)
{
/*
* Register a probe that is called before all other probes
* to set ignore_pid if next or prev do not match.
* Register a probe this is called after all other probes
* to only keep ignore_pid set if next pid matches.
*/
register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
tr, INT_MAX);
register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
tr, 0);
register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
tr, INT_MAX);
register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
tr, 0);
register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
tr, INT_MAX);
register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
tr, 0);
register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
tr, INT_MAX);
register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
tr, 0);
}
static ssize_t
event_pid_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos, int type)
{
struct seq_file *m = filp->private_data;
struct trace_array *tr = m->private;
struct trace_pid_list *filtered_pids = NULL;
struct trace_pid_list *other_pids = NULL;
struct trace_pid_list *pid_list;
struct trace_event_file *file;
ssize_t ret;
if (!cnt)
return 0;
ret = tracing_update_buffers(tr);
if (ret < 0)
return ret;
mutex_lock(&event_mutex);
if (type == TRACE_PIDS) {
filtered_pids = rcu_dereference_protected(tr->filtered_pids,
lockdep_is_held(&event_mutex));
other_pids = rcu_dereference_protected(tr->filtered_no_pids,
lockdep_is_held(&event_mutex));
} else {
filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
lockdep_is_held(&event_mutex));
other_pids = rcu_dereference_protected(tr->filtered_pids,
lockdep_is_held(&event_mutex));
}
ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
if (ret < 0)
goto out;
if (type == TRACE_PIDS)
rcu_assign_pointer(tr->filtered_pids, pid_list);
else
rcu_assign_pointer(tr->filtered_no_pids, pid_list);
list_for_each_entry(file, &tr->events, list) {
set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
}
if (filtered_pids) {
tracepoint_synchronize_unregister();
trace_pid_list_free(filtered_pids);
} else if (pid_list && !other_pids) {
register_pid_events(tr);
}
/*
* Ignoring of pids is done at task switch. But we have to
* check for those tasks that are currently running.
* Always do this in case a pid was appended or removed.
*/
on_each_cpu(ignore_task_cpu, tr, 1);
out:
mutex_unlock(&event_mutex);
if (ret > 0)
*ppos += ret;
return ret;
}
static ssize_t
ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
}
static ssize_t
ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
}
static int ftrace_event_avail_open(struct inode *inode, struct file *file);
static int ftrace_event_set_open(struct inode *inode, struct file *file);
static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
static int ftrace_event_release(struct inode *inode, struct file *file);
static const struct seq_operations show_event_seq_ops = {
.start = t_start,
.next = t_next,
.show = t_show,
.stop = t_stop,
};
static const struct seq_operations show_set_event_seq_ops = {
.start = s_start,
.next = s_next,
.show = t_show,
.stop = t_stop,
};
static const struct seq_operations show_set_pid_seq_ops = {
.start = p_start,
.next = p_next,
.show = trace_pid_show,
.stop = p_stop,
};
static const struct seq_operations show_set_no_pid_seq_ops = {
.start = np_start,
.next = np_next,
.show = trace_pid_show,
.stop = p_stop,
};
static const struct file_operations ftrace_avail_fops = {
.open = ftrace_event_avail_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct file_operations ftrace_set_event_fops = {
.open = ftrace_event_set_open,
.read = seq_read,
.write = ftrace_event_write,
.llseek = seq_lseek,
.release = ftrace_event_release,
};
static const struct file_operations ftrace_set_event_pid_fops = {
.open = ftrace_event_set_pid_open,
.read = seq_read,
.write = ftrace_event_pid_write,
.llseek = seq_lseek,
.release = ftrace_event_release,
};
static const struct file_operations ftrace_set_event_notrace_pid_fops = {
.open = ftrace_event_set_npid_open,
.read = seq_read,
.write = ftrace_event_npid_write,
.llseek = seq_lseek,
.release = ftrace_event_release,
};
static const struct file_operations ftrace_enable_fops = {
.open = tracing_open_file_tr,
.read = event_enable_read,
.write = event_enable_write,
.release = tracing_release_file_tr,
.llseek = default_llseek,
};
static const struct file_operations ftrace_event_format_fops = {
.open = trace_format_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#ifdef CONFIG_PERF_EVENTS
static const struct file_operations ftrace_event_id_fops = {
.read = event_id_read,
.llseek = default_llseek,
};
#endif
static const struct file_operations ftrace_event_filter_fops = {
.open = tracing_open_file_tr,
.read = event_filter_read,
.write = event_filter_write,
.release = tracing_release_file_tr,
.llseek = default_llseek,
};
static const struct file_operations ftrace_subsystem_filter_fops = {
.open = subsystem_open,
.read = subsystem_filter_read,
.write = subsystem_filter_write,
.llseek = default_llseek,
.release = subsystem_release,
};
static const struct file_operations ftrace_system_enable_fops = {
.open = subsystem_open,
.read = system_enable_read,
.write = system_enable_write,
.llseek = default_llseek,
.release = subsystem_release,
};
static const struct file_operations ftrace_tr_enable_fops = {
.open = system_tr_open,
.read = system_enable_read,
.write = system_enable_write,
.llseek = default_llseek,
.release = subsystem_release,
};
static const struct file_operations ftrace_show_header_page_fops = {
.open = tracing_open_generic_tr,
.read = show_header_page_file,
.llseek = default_llseek,
.release = tracing_release_generic_tr,
};
static const struct file_operations ftrace_show_header_event_fops = {
.open = tracing_open_generic_tr,
.read = show_header_event_file,
.llseek = default_llseek,
.release = tracing_release_generic_tr,
};
static int
ftrace_event_open(struct inode *inode, struct file *file,
const struct seq_operations *seq_ops)
{
struct seq_file *m;
int ret;
ret = security_locked_down(LOCKDOWN_TRACEFS);
if (ret)
return ret;
ret = seq_open(file, seq_ops);
if (ret < 0)
return ret;
m = file->private_data;
/* copy tr over to seq ops */
m->private = inode->i_private;
return ret;
}
static int ftrace_event_release(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
trace_array_put(tr);
return seq_release(inode, file);
}
static int
ftrace_event_avail_open(struct inode *inode, struct file *file)
{
const struct seq_operations *seq_ops = &show_event_seq_ops;
/* Checks for tracefs lockdown */
return ftrace_event_open(inode, file, seq_ops);
}
static int
ftrace_event_set_open(struct inode *inode, struct file *file)
{
const struct seq_operations *seq_ops = &show_set_event_seq_ops;
struct trace_array *tr = inode->i_private;
int ret;
ret = tracing_check_open_get_tr(tr);
if (ret)
return ret;
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC))
ftrace_clear_events(tr);
ret = ftrace_event_open(inode, file, seq_ops);
if (ret < 0)
trace_array_put(tr);
return ret;
}
static int
ftrace_event_set_pid_open(struct inode *inode, struct file *file)
{
const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
struct trace_array *tr = inode->i_private;
int ret;
ret = tracing_check_open_get_tr(tr);
if (ret)
return ret;
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC))
ftrace_clear_event_pids(tr, TRACE_PIDS);
ret = ftrace_event_open(inode, file, seq_ops);
if (ret < 0)
trace_array_put(tr);
return ret;
}
static int
ftrace_event_set_npid_open(struct inode *inode, struct file *file)
{
const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
struct trace_array *tr = inode->i_private;
int ret;
ret = tracing_check_open_get_tr(tr);
if (ret)
return ret;
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC))
ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
ret = ftrace_event_open(inode, file, seq_ops);
if (ret < 0)
trace_array_put(tr);
return ret;
}
static struct event_subsystem *
create_new_subsystem(const char *name)
{
struct event_subsystem *system;
/* need to create new entry */
system = kmalloc(sizeof(*system), GFP_KERNEL);
if (!system)
return NULL;
system->ref_count = 1;
/* Only allocate if dynamic (kprobes and modules) */
system->name = kstrdup_const(name, GFP_KERNEL);
if (!system->name)
goto out_free;
system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
if (!system->filter)
goto out_free;
list_add(&system->list, &event_subsystems);
return system;
out_free:
kfree_const(system->name);
kfree(system);
return NULL;
}
static int system_callback(const char *name, umode_t *mode, void **data,
const struct file_operations **fops)
{
if (strcmp(name, "filter") == 0)
*fops = &ftrace_subsystem_filter_fops;
else if (strcmp(name, "enable") == 0)
*fops = &ftrace_system_enable_fops;
else
return 0;
*mode = TRACE_MODE_WRITE;
return 1;
}
static struct eventfs_inode *
event_subsystem_dir(struct trace_array *tr, const char *name,
struct trace_event_file *file, struct eventfs_inode *parent)
{
struct event_subsystem *system, *iter;
struct trace_subsystem_dir *dir;
struct eventfs_inode *ei;
int nr_entries;
static struct eventfs_entry system_entries[] = {
{
.name = "filter",
.callback = system_callback,
},
{
.name = "enable",
.callback = system_callback,
}
};
/* First see if we did not already create this dir */
list_for_each_entry(dir, &tr->systems, list) {
system = dir->subsystem;
if (strcmp(system->name, name) == 0) {
dir->nr_events++;
file->system = dir;
return dir->ei;
}
}
/* Now see if the system itself exists. */
system = NULL;
list_for_each_entry(iter, &event_subsystems, list) {
if (strcmp(iter->name, name) == 0) {
system = iter;
break;
}
}
dir = kmalloc(sizeof(*dir), GFP_KERNEL);
if (!dir)
goto out_fail;
if (!system) {
system = create_new_subsystem(name);
if (!system)
goto out_free;
} else
__get_system(system);
/* ftrace only has directories no files */
if (strcmp(name, "ftrace") == 0)
nr_entries = 0;
else
nr_entries = ARRAY_SIZE(system_entries);
ei = eventfs_create_dir(name, parent, system_entries, nr_entries, dir);
if (IS_ERR(ei)) {
pr_warn("Failed to create system directory %s\n", name);
__put_system(system);
goto out_free;
}
dir->ei = ei;
dir->tr = tr;
dir->ref_count = 1;
dir->nr_events = 1;
dir->subsystem = system;
file->system = dir;
list_add(&dir->list, &tr->systems);
return dir->ei;
out_free:
kfree(dir);
out_fail:
/* Only print this message if failed on memory allocation */
if (!dir || !system)
pr_warn("No memory to create event subsystem %s\n", name);
return NULL;
}
static int
event_define_fields(struct trace_event_call *call)
{
struct list_head *head;
int ret = 0;
/*
* Other events may have the same class. Only update
* the fields if they are not already defined.
*/
head = trace_get_fields(call);
if (list_empty(head)) {
struct trace_event_fields *field = call->class->fields_array;
unsigned int offset = sizeof(struct trace_entry);
for (; field->type; field++) {
if (field->type == TRACE_FUNCTION_TYPE) {
field->define_fields(call);
break;
}
offset = ALIGN(offset, field->align);
ret = trace_define_field_ext(call, field->type, field->name,
offset, field->size,
field->is_signed, field->filter_type,
field->len);
if (WARN_ON_ONCE(ret)) {
pr_err("error code is %d\n", ret);
break;
}
offset += field->size;
}
}
return ret;
}
static int event_callback(const char *name, umode_t *mode, void **data,
const struct file_operations **fops)
{
struct trace_event_file *file = *data;
struct trace_event_call *call = file->event_call;
if (strcmp(name, "format") == 0) {
*mode = TRACE_MODE_READ;
*fops = &ftrace_event_format_fops;
return 1;
}
/*
* Only event directories that can be enabled should have
* triggers or filters, with the exception of the "print"
* event that can have a "trigger" file.
*/
if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
if (call->class->reg && strcmp(name, "enable") == 0) {
*mode = TRACE_MODE_WRITE;
*fops = &ftrace_enable_fops;
return 1;
}
if (strcmp(name, "filter") == 0) {
*mode = TRACE_MODE_WRITE;
*fops = &ftrace_event_filter_fops;
return 1;
}
}
if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
strcmp(trace_event_name(call), "print") == 0) {
if (strcmp(name, "trigger") == 0) {
*mode = TRACE_MODE_WRITE;
*fops = &event_trigger_fops;
return 1;
}
}
#ifdef CONFIG_PERF_EVENTS
if (call->event.type && call->class->reg &&
strcmp(name, "id") == 0) {
*mode = TRACE_MODE_READ;
*data = (void *)(long)call->event.type;
*fops = &ftrace_event_id_fops;
return 1;
}
#endif
#ifdef CONFIG_HIST_TRIGGERS
if (strcmp(name, "hist") == 0) {
*mode = TRACE_MODE_READ;
*fops = &event_hist_fops;
return 1;
}
#endif
#ifdef CONFIG_HIST_TRIGGERS_DEBUG
if (strcmp(name, "hist_debug") == 0) {
*mode = TRACE_MODE_READ;
*fops = &event_hist_debug_fops;
return 1;
}
#endif
#ifdef CONFIG_TRACE_EVENT_INJECT
if (call->event.type && call->class->reg &&
strcmp(name, "inject") == 0) {
*mode = 0200;
*fops = &event_inject_fops;
return 1;
}
#endif
return 0;
}
/* The file is incremented on creation and freeing the enable file decrements it */
static void event_release(const char *name, void *data)
{
struct trace_event_file *file = data;
event_file_put(file);
}
static int
event_create_dir(struct eventfs_inode *parent, struct trace_event_file *file)
{
struct trace_event_call *call = file->event_call;
struct trace_array *tr = file->tr;
struct eventfs_inode *e_events;
struct eventfs_inode *ei;
const char *name;
int nr_entries;
int ret;
static struct eventfs_entry event_entries[] = {
{
.name = "enable",
.callback = event_callback,
.release = event_release,
},
{
.name = "filter",
.callback = event_callback,
},
{
.name = "trigger",
.callback = event_callback,
},
{
.name = "format",
.callback = event_callback,
},
#ifdef CONFIG_PERF_EVENTS
{
.name = "id",
.callback = event_callback,
},
#endif
#ifdef CONFIG_HIST_TRIGGERS
{
.name = "hist",
.callback = event_callback,
},
#endif
#ifdef CONFIG_HIST_TRIGGERS_DEBUG
{
.name = "hist_debug",
.callback = event_callback,
},
#endif
#ifdef CONFIG_TRACE_EVENT_INJECT
{
.name = "inject",
.callback = event_callback,
},
#endif
};
/*
* If the trace point header did not define TRACE_SYSTEM
* then the system would be called "TRACE_SYSTEM". This should
* never happen.
*/
if (WARN_ON_ONCE(strcmp(call->class->system, TRACE_SYSTEM) == 0))
return -ENODEV;
e_events = event_subsystem_dir(tr, call->class->system, file, parent);
if (!e_events)
return -ENOMEM;
nr_entries = ARRAY_SIZE(event_entries);
name = trace_event_name(call);
ei = eventfs_create_dir(name, e_events, event_entries, nr_entries, file);
if (IS_ERR(ei)) {
pr_warn("Could not create tracefs '%s' directory\n", name);
return -1;
}
file->ei = ei;
ret = event_define_fields(call);
if (ret < 0) {
pr_warn("Could not initialize trace point events/%s\n", name);
return ret;
}
/* Gets decremented on freeing of the "enable" file */
event_file_get(file);
return 0;
}
static void remove_event_from_tracers(struct trace_event_call *call)
{
struct trace_event_file *file;
struct trace_array *tr;
do_for_each_event_file_safe(tr, file) {
if (file->event_call != call)
continue;
remove_event_file_dir(file);
/*
* The do_for_each_event_file_safe() is
* a double loop. After finding the call for this
* trace_array, we use break to jump to the next
* trace_array.
*/
break;
} while_for_each_event_file();
}
static void event_remove(struct trace_event_call *call)
{
struct trace_array *tr;
struct trace_event_file *file;
do_for_each_event_file(tr, file) {
if (file->event_call != call)
continue;
if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
tr->clear_trace = true;
ftrace_event_enable_disable(file, 0);
/*
* The do_for_each_event_file() is
* a double loop. After finding the call for this
* trace_array, we use break to jump to the next
* trace_array.
*/
break;
} while_for_each_event_file();
if (call->event.funcs)
__unregister_trace_event(&call->event);
remove_event_from_tracers(call);
list_del(&call->list);
}
static int event_init(struct trace_event_call *call)
{
int ret = 0;
const char *name;
name = trace_event_name(call);
if (WARN_ON(!name))
return -EINVAL;
if (call->class->raw_init) {
ret = call->class->raw_init(call);
if (ret < 0 && ret != -ENOSYS)
pr_warn("Could not initialize trace events/%s\n", name);
}
return ret;
}
static int
__register_event(struct trace_event_call *call, struct module *mod)
{
int ret;
ret = event_init(call);
if (ret < 0)
return ret;
list_add(&call->list, &ftrace_events);
if (call->flags & TRACE_EVENT_FL_DYNAMIC)
atomic_set(&call->refcnt, 0);
else
call->module = mod;
return 0;
}
static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
{
int rlen;
int elen;
/* Find the length of the eval value as a string */
elen = snprintf(ptr, 0, "%ld", map->eval_value);
/* Make sure there's enough room to replace the string with the value */
if (len < elen)
return NULL;
snprintf(ptr, elen + 1, "%ld", map->eval_value);
/* Get the rest of the string of ptr */
rlen = strlen(ptr + len);
memmove(ptr + elen, ptr + len, rlen);
/* Make sure we end the new string */
ptr[elen + rlen] = 0;
return ptr + elen;
}
static void update_event_printk(struct trace_event_call *call,
struct trace_eval_map *map)
{
char *ptr;
int quote = 0;
int len = strlen(map->eval_string);
for (ptr = call->print_fmt; *ptr; ptr++) {
if (*ptr == '\\') {
ptr++;
/* paranoid */
if (!*ptr)
break;
continue;
}
if (*ptr == '"') {
quote ^= 1;
continue;
}
if (quote)
continue;
if (isdigit(*ptr)) {
/* skip numbers */
do {
ptr++;
/* Check for alpha chars like ULL */
} while (isalnum(*ptr));
if (!*ptr)
break;
/*
* A number must have some kind of delimiter after
* it, and we can ignore that too.
*/
continue;
}
if (isalpha(*ptr) || *ptr == '_') {
if (strncmp(map->eval_string, ptr, len) == 0 &&
!isalnum(ptr[len]) && ptr[len] != '_') {
ptr = eval_replace(ptr, map, len);
/* enum/sizeof string smaller than value */
if (WARN_ON_ONCE(!ptr))
return;
/*
* No need to decrement here, as eval_replace()
* returns the pointer to the character passed
* the eval, and two evals can not be placed
* back to back without something in between.
* We can skip that something in between.
*/
continue;
}
skip_more:
do {
ptr++;
} while (isalnum(*ptr) || *ptr == '_');
if (!*ptr)
break;
/*
* If what comes after this variable is a '.' or
* '->' then we can continue to ignore that string.
*/
if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
ptr += *ptr == '.' ? 1 : 2;
if (!*ptr)
break;
goto skip_more;
}
/*
* Once again, we can skip the delimiter that came
* after the string.
*/
continue;
}
}
}
static void add_str_to_module(struct module *module, char *str)
{
struct module_string *modstr;
modstr = kmalloc(sizeof(*modstr), GFP_KERNEL);
/*
* If we failed to allocate memory here, then we'll just
* let the str memory leak when the module is removed.
* If this fails to allocate, there's worse problems than
* a leaked string on module removal.
*/
if (WARN_ON_ONCE(!modstr))
return;
modstr->module = module;
modstr->str = str;
list_add(&modstr->next, &module_strings);
}
static void update_event_fields(struct trace_event_call *call,
struct trace_eval_map *map)
{
struct ftrace_event_field *field;
struct list_head *head;
char *ptr;
char *str;
int len = strlen(map->eval_string);
/* Dynamic events should never have field maps */
if (WARN_ON_ONCE(call->flags & TRACE_EVENT_FL_DYNAMIC))
return;
head = trace_get_fields(call);
list_for_each_entry(field, head, link) {
ptr = strchr(field->type, '[');
if (!ptr)
continue;
ptr++;
if (!isalpha(*ptr) && *ptr != '_')
continue;
if (strncmp(map->eval_string, ptr, len) != 0)
continue;
str = kstrdup(field->type, GFP_KERNEL);
if (WARN_ON_ONCE(!str))
return;
ptr = str + (ptr - field->type);
ptr = eval_replace(ptr, map, len);
/* enum/sizeof string smaller than value */
if (WARN_ON_ONCE(!ptr)) {
kfree(str);
continue;
}
/*
* If the event is part of a module, then we need to free the string
* when the module is removed. Otherwise, it will stay allocated
* until a reboot.
*/
if (call->module)
add_str_to_module(call->module, str);
field->type = str;
}
}
void trace_event_eval_update(struct trace_eval_map **map, int len)
{
struct trace_event_call *call, *p;
const char *last_system = NULL;
bool first = false;
int last_i;
int i;
down_write(&trace_event_sem);
list_for_each_entry_safe(call, p, &ftrace_events, list) {
/* events are usually grouped together with systems */
if (!last_system || call->class->system != last_system) {
first = true;
last_i = 0;
last_system = call->class->system;
}
/*
* Since calls are grouped by systems, the likelihood that the
* next call in the iteration belongs to the same system as the
* previous call is high. As an optimization, we skip searching
* for a map[] that matches the call's system if the last call
* was from the same system. That's what last_i is for. If the
* call has the same system as the previous call, then last_i
* will be the index of the first map[] that has a matching
* system.
*/
for (i = last_i; i < len; i++) {
if (call->class->system == map[i]->system) {
/* Save the first system if need be */
if (first) {
last_i = i;
first = false;
}
update_event_printk(call, map[i]);
update_event_fields(call, map[i]);
}
}
cond_resched();
}
up_write(&trace_event_sem);
}
static bool event_in_systems(struct trace_event_call *call,
const char *systems)
{
const char *system;
const char *p;
if (!systems)
return true;
system = call->class->system;
p = strstr(systems, system);
if (!p)
return false;
if (p != systems && !isspace(*(p - 1)) && *(p - 1) != ',')
return false;
p += strlen(system);
return !*p || isspace(*p) || *p == ',';
}
static struct trace_event_file *
trace_create_new_event(struct trace_event_call *call,
struct trace_array *tr)
{
struct trace_pid_list *no_pid_list;
struct trace_pid_list *pid_list;
struct trace_event_file *file;
unsigned int first;
if (!event_in_systems(call, tr->system_names))
return NULL;
file = kmem_cache_alloc(file_cachep, GFP_TRACE);
if (!file)
return ERR_PTR(-ENOMEM);
pid_list = rcu_dereference_protected(tr->filtered_pids,
lockdep_is_held(&event_mutex));
no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
lockdep_is_held(&event_mutex));
if (!trace_pid_list_first(pid_list, &first) ||
!trace_pid_list_first(no_pid_list, &first))
file->flags |= EVENT_FILE_FL_PID_FILTER;
file->event_call = call;
file->tr = tr;
atomic_set(&file->sm_ref, 0);
atomic_set(&file->tm_ref, 0);
INIT_LIST_HEAD(&file->triggers);
list_add(&file->list, &tr->events);
refcount_set(&file->ref, 1);
return file;
}
#define MAX_BOOT_TRIGGERS 32
static struct boot_triggers {
const char *event;
char *trigger;
} bootup_triggers[MAX_BOOT_TRIGGERS];
static char bootup_trigger_buf[COMMAND_LINE_SIZE];
static int nr_boot_triggers;
static __init int setup_trace_triggers(char *str)
{
char *trigger;
char *buf;
int i;
strscpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE);
trace_set_ring_buffer_expanded(NULL);
disable_tracing_selftest("running event triggers");
buf = bootup_trigger_buf;
for (i = 0; i < MAX_BOOT_TRIGGERS; i++) {
trigger = strsep(&buf, ",");
if (!trigger)
break;
bootup_triggers[i].event = strsep(&trigger, ".");
bootup_triggers[i].trigger = trigger;
if (!bootup_triggers[i].trigger)
break;
}
nr_boot_triggers = i;
return 1;
}
__setup("trace_trigger=", setup_trace_triggers);
/* Add an event to a trace directory */
static int
__trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
{
struct trace_event_file *file;
file = trace_create_new_event(call, tr);
/*
* trace_create_new_event() returns ERR_PTR(-ENOMEM) if failed
* allocation, or NULL if the event is not part of the tr->system_names.
* When the event is not part of the tr->system_names, return zero, not
* an error.
*/
if (!file)
return 0;
if (IS_ERR(file))
return PTR_ERR(file);
if (eventdir_initialized)
return event_create_dir(tr->event_dir, file);
else
return event_define_fields(call);
}
static void trace_early_triggers(struct trace_event_file *file, const char *name)
{
int ret;
int i;
for (i = 0; i < nr_boot_triggers; i++) {
if (strcmp(name, bootup_triggers[i].event))
continue;
mutex_lock(&event_mutex);
ret = trigger_process_regex(file, bootup_triggers[i].trigger);
mutex_unlock(&event_mutex);
if (ret)
pr_err("Failed to register trigger '%s' on event %s\n",
bootup_triggers[i].trigger,
bootup_triggers[i].event);
}
}
/*
* Just create a descriptor for early init. A descriptor is required
* for enabling events at boot. We want to enable events before
* the filesystem is initialized.
*/
static int
__trace_early_add_new_event(struct trace_event_call *call,
struct trace_array *tr)
{
struct trace_event_file *file;
int ret;
file = trace_create_new_event(call, tr);
/*
* trace_create_new_event() returns ERR_PTR(-ENOMEM) if failed
* allocation, or NULL if the event is not part of the tr->system_names.
* When the event is not part of the tr->system_names, return zero, not
* an error.
*/
if (!file)
return 0;
if (IS_ERR(file))
return PTR_ERR(file);
ret = event_define_fields(call);
if (ret)
return ret;
trace_early_triggers(file, trace_event_name(call));
return 0;
}
struct ftrace_module_file_ops;
static void __add_event_to_tracers(struct trace_event_call *call);
/* Add an additional event_call dynamically */
int trace_add_event_call(struct trace_event_call *call)
{
int ret;
lockdep_assert_held(&event_mutex);
mutex_lock(&trace_types_lock);
ret = __register_event(call, NULL);
if (ret >= 0)
__add_event_to_tracers(call);
mutex_unlock(&trace_types_lock);
return ret;
}
EXPORT_SYMBOL_GPL(trace_add_event_call);
/*
* Must be called under locking of trace_types_lock, event_mutex and
* trace_event_sem.
*/
static void __trace_remove_event_call(struct trace_event_call *call)
{
event_remove(call);
trace_destroy_fields(call);
free_event_filter(call->filter);
call->filter = NULL;
}
static int probe_remove_event_call(struct trace_event_call *call)
{
struct trace_array *tr;
struct trace_event_file *file;
#ifdef CONFIG_PERF_EVENTS
if (call->perf_refcount)
return -EBUSY;
#endif
do_for_each_event_file(tr, file) {
if (file->event_call != call)
continue;
/*
* We can't rely on ftrace_event_enable_disable(enable => 0)
* we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
* TRACE_REG_UNREGISTER.
*/
if (file->flags & EVENT_FILE_FL_ENABLED)
goto busy;
if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
tr->clear_trace = true;
/*
* The do_for_each_event_file_safe() is
* a double loop. After finding the call for this
* trace_array, we use break to jump to the next
* trace_array.
*/
break;
} while_for_each_event_file();
__trace_remove_event_call(call);
return 0;
busy:
/* No need to clear the trace now */
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
tr->clear_trace = false;
}
return -EBUSY;
}
/* Remove an event_call */
int trace_remove_event_call(struct trace_event_call *call)
{
int ret;
lockdep_assert_held(&event_mutex);
mutex_lock(&trace_types_lock);
down_write(&trace_event_sem);
ret = probe_remove_event_call(call);
up_write(&trace_event_sem);
mutex_unlock(&trace_types_lock);
return ret;
}
EXPORT_SYMBOL_GPL(trace_remove_event_call);
#define for_each_event(event, start, end) \
for (event = start; \
(unsigned long)event < (unsigned long)end; \
event++)
#ifdef CONFIG_MODULES
static void trace_module_add_events(struct module *mod)
{
struct trace_event_call **call, **start, **end;
if (!mod->num_trace_events)
return;
/* Don't add infrastructure for mods without tracepoints */
if (trace_module_has_bad_taint(mod)) {
pr_err("%s: module has bad taint, not creating trace events\n",
mod->name);
return;
}
start = mod->trace_events;
end = mod->trace_events + mod->num_trace_events;
for_each_event(call, start, end) {
__register_event(*call, mod);
__add_event_to_tracers(*call);
}
}
static void trace_module_remove_events(struct module *mod)
{
struct trace_event_call *call, *p;
struct module_string *modstr, *m;
down_write(&trace_event_sem);
list_for_each_entry_safe(call, p, &ftrace_events, list) {
if ((call->flags & TRACE_EVENT_FL_DYNAMIC) || !call->module)
continue;
if (call->module == mod)
__trace_remove_event_call(call);
}
/* Check for any strings allocade for this module */
list_for_each_entry_safe(modstr, m, &module_strings, next) {
if (modstr->module != mod)
continue;
list_del(&modstr->next);
kfree(modstr->str);
kfree(modstr);
}
up_write(&trace_event_sem);
/*
* 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_unlocked();
}
static int trace_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct module *mod = data;
mutex_lock(&event_mutex);
mutex_lock(&trace_types_lock);
switch (val) {
case MODULE_STATE_COMING:
trace_module_add_events(mod);
break;
case MODULE_STATE_GOING:
trace_module_remove_events(mod);
break;
}
mutex_unlock(&trace_types_lock);
mutex_unlock(&event_mutex);
return NOTIFY_OK;
}
static struct notifier_block trace_module_nb = {
.notifier_call = trace_module_notify,
.priority = 1, /* higher than trace.c module notify */
};
#endif /* CONFIG_MODULES */
/* Create a new event directory structure for a trace directory. */
static void
__trace_add_event_dirs(struct trace_array *tr)
{
struct trace_event_call *call;
int ret;
list_for_each_entry(call, &ftrace_events, list) {
ret = __trace_add_new_event(call, tr);
if (ret < 0)
pr_warn("Could not create directory for event %s\n",
trace_event_name(call));
}
}
/* Returns any file that matches the system and event */
struct trace_event_file *
__find_event_file(struct trace_array *tr, const char *system, const char *event)
{
struct trace_event_file *file;
struct trace_event_call *call;
const char *name;
list_for_each_entry(file, &tr->events, list) {
call = file->event_call;
name = trace_event_name(call);
if (!name || !call->class)
continue;
if (strcmp(event, name) == 0 &&
strcmp(system, call->class->system) == 0)
return file;
}
return NULL;
}
/* Returns valid trace event files that match system and event */
struct trace_event_file *
find_event_file(struct trace_array *tr, const char *system, const char *event)
{
struct trace_event_file *file;
file = __find_event_file(tr, system, event);
if (!file || !file->event_call->class->reg ||
file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
return NULL;
return file;
}
/**
* trace_get_event_file - Find and return a trace event file
* @instance: The name of the trace instance containing the event
* @system: The name of the system containing the event
* @event: The name of the event
*
* Return a trace event file given the trace instance name, trace
* system, and trace event name. If the instance name is NULL, it
* refers to the top-level trace array.
*
* This function will look it up and return it if found, after calling
* trace_array_get() to prevent the instance from going away, and
* increment the event's module refcount to prevent it from being
* removed.
*
* To release the file, call trace_put_event_file(), which will call
* trace_array_put() and decrement the event's module refcount.
*
* Return: The trace event on success, ERR_PTR otherwise.
*/
struct trace_event_file *trace_get_event_file(const char *instance,
const char *system,
const char *event)
{
struct trace_array *tr = top_trace_array();
struct trace_event_file *file = NULL;
int ret = -EINVAL;
if (instance) {
tr = trace_array_find_get(instance);
if (!tr)
return ERR_PTR(-ENOENT);
} else {
ret = trace_array_get(tr);
if (ret)
return ERR_PTR(ret);
}
mutex_lock(&event_mutex);
file = find_event_file(tr, system, event);
if (!file) {
trace_array_put(tr);
ret = -EINVAL;
goto out;
}
/* Don't let event modules unload while in use */
ret = trace_event_try_get_ref(file->event_call);
if (!ret) {
trace_array_put(tr);
ret = -EBUSY;
goto out;
}
ret = 0;
out:
mutex_unlock(&event_mutex);
if (ret)
file = ERR_PTR(ret);
return file;
}
EXPORT_SYMBOL_GPL(trace_get_event_file);
/**
* trace_put_event_file - Release a file from trace_get_event_file()
* @file: The trace event file
*
* If a file was retrieved using trace_get_event_file(), this should
* be called when it's no longer needed. It will cancel the previous
* trace_array_get() called by that function, and decrement the
* event's module refcount.
*/
void trace_put_event_file(struct trace_event_file *file)
{
mutex_lock(&event_mutex);
trace_event_put_ref(file->event_call);
mutex_unlock(&event_mutex);
trace_array_put(file->tr);
}
EXPORT_SYMBOL_GPL(trace_put_event_file);
#ifdef CONFIG_DYNAMIC_FTRACE
/* Avoid typos */
#define ENABLE_EVENT_STR "enable_event"
#define DISABLE_EVENT_STR "disable_event"
struct event_probe_data {
struct trace_event_file *file;
unsigned long count;
int ref;
bool enable;
};
static void update_event_probe(struct event_probe_data *data)
{
if (data->enable)
clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
else
set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
}
static void
event_enable_probe(unsigned long ip, unsigned long parent_ip,
struct trace_array *tr, struct ftrace_probe_ops *ops,
void *data)
{
struct ftrace_func_mapper *mapper = data;
struct event_probe_data *edata;
void **pdata;
pdata = ftrace_func_mapper_find_ip(mapper, ip);
if (!pdata || !*pdata)
return;
edata = *pdata;
update_event_probe(edata);
}
static void
event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
struct trace_array *tr, struct ftrace_probe_ops *ops,
void *data)
{
struct ftrace_func_mapper *mapper = data;
struct event_probe_data *edata;
void **pdata;
pdata = ftrace_func_mapper_find_ip(mapper, ip);
if (!pdata || !*pdata)
return;
edata = *pdata;
if (!edata->count)
return;
/* Skip if the event is in a state we want to switch to */
if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
return;
if (edata->count != -1)
(edata->count)--;
update_event_probe(edata);
}
static int
event_enable_print(struct seq_file *m, unsigned long ip,
struct ftrace_probe_ops *ops, void *data)
{
struct ftrace_func_mapper *mapper = data;
struct event_probe_data *edata;
void **pdata;
pdata = ftrace_func_mapper_find_ip(mapper, ip);
if (WARN_ON_ONCE(!pdata || !*pdata))
return 0;
edata = *pdata;
seq_printf(m, "%ps:", (void *)ip);
seq_printf(m, "%s:%s:%s",
edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
edata->file->event_call->class->system,
trace_event_name(edata->file->event_call));
if (edata->count == -1)
seq_puts(m, ":unlimited\n");
else
seq_printf(m, ":count=%ld\n", edata->count);
return 0;
}
static int
event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
unsigned long ip, void *init_data, void **data)
{
struct ftrace_func_mapper *mapper = *data;
struct event_probe_data *edata = init_data;
int ret;
if (!mapper) {
mapper = allocate_ftrace_func_mapper();
if (!mapper)
return -ENODEV;
*data = mapper;
}
ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
if (ret < 0)
return ret;
edata->ref++;
return 0;
}
static int free_probe_data(void *data)
{
struct event_probe_data *edata = data;
edata->ref--;
if (!edata->ref) {
/* Remove the SOFT_MODE flag */
__ftrace_event_enable_disable(edata->file, 0, 1);
trace_event_put_ref(edata->file->event_call);
kfree(edata);
}
return 0;
}
static void
event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
unsigned long ip, void *data)
{
struct ftrace_func_mapper *mapper = data;
struct event_probe_data *edata;
if (!ip) {
if (!mapper)
return;
free_ftrace_func_mapper(mapper, free_probe_data);
return;
}
edata = ftrace_func_mapper_remove_ip(mapper, ip);
if (WARN_ON_ONCE(!edata))
return;
if (WARN_ON_ONCE(edata->ref <= 0))
return;
free_probe_data(edata);
}
static struct ftrace_probe_ops event_enable_probe_ops = {
.func = event_enable_probe,
.print = event_enable_print,
.init = event_enable_init,
.free = event_enable_free,
};
static struct ftrace_probe_ops event_enable_count_probe_ops = {
.func = event_enable_count_probe,
.print = event_enable_print,
.init = event_enable_init,
.free = event_enable_free,
};
static struct ftrace_probe_ops event_disable_probe_ops = {
.func = event_enable_probe,
.print = event_enable_print,
.init = event_enable_init,
.free = event_enable_free,
};
static struct ftrace_probe_ops event_disable_count_probe_ops = {
.func = event_enable_count_probe,
.print = event_enable_print,
.init = event_enable_init,
.free = event_enable_free,
};
static int
event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
char *glob, char *cmd, char *param, int enabled)
{
struct trace_event_file *file;
struct ftrace_probe_ops *ops;
struct event_probe_data *data;
const char *system;
const char *event;
char *number;
bool enable;
int ret;
if (!tr)
return -ENODEV;
/* hash funcs only work with set_ftrace_filter */
if (!enabled || !param)
return -EINVAL;
system = strsep(&param, ":");
if (!param)
return -EINVAL;
event = strsep(&param, ":");
mutex_lock(&event_mutex);
ret = -EINVAL;
file = find_event_file(tr, system, event);
if (!file)
goto out;
enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
if (enable)
ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
else
ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
if (glob[0] == '!') {
ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
goto out;
}
ret = -ENOMEM;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
goto out;
data->enable = enable;
data->count = -1;
data->file = file;
if (!param)
goto out_reg;
number = strsep(&param, ":");
ret = -EINVAL;
if (!strlen(number))
goto out_free;
/*
* We use the callback data field (which is a pointer)
* as our counter.
*/
ret = kstrtoul(number, 0, &data->count);
if (ret)
goto out_free;
out_reg:
/* Don't let event modules unload while probe registered */
ret = trace_event_try_get_ref(file->event_call);
if (!ret) {
ret = -EBUSY;
goto out_free;
}
ret = __ftrace_event_enable_disable(file, 1, 1);
if (ret < 0)
goto out_put;
ret = register_ftrace_function_probe(glob, tr, ops, data);
/*
* The above returns on success the # of functions enabled,
* but if it didn't find any functions it returns zero.
* Consider no functions a failure too.
*/
if (!ret) {
ret = -ENOENT;
goto out_disable;
} else if (ret < 0)
goto out_disable;
/* Just return zero, not the number of enabled functions */
ret = 0;
out:
mutex_unlock(&event_mutex);
return ret;
out_disable:
__ftrace_event_enable_disable(file, 0, 1);
out_put:
trace_event_put_ref(file->event_call);
out_free:
kfree(data);
goto out;
}
static struct ftrace_func_command event_enable_cmd = {
.name = ENABLE_EVENT_STR,
.func = event_enable_func,
};
static struct ftrace_func_command event_disable_cmd = {
.name = DISABLE_EVENT_STR,
.func = event_enable_func,
};
static __init int register_event_cmds(void)
{
int ret;
ret = register_ftrace_command(&event_enable_cmd);
if (WARN_ON(ret < 0))
return ret;
ret = register_ftrace_command(&event_disable_cmd);
if (WARN_ON(ret < 0))
unregister_ftrace_command(&event_enable_cmd);
return ret;
}
#else
static inline int register_event_cmds(void) { return 0; }
#endif /* CONFIG_DYNAMIC_FTRACE */
/*
* The top level array and trace arrays created by boot-time tracing
* have already had its trace_event_file descriptors created in order
* to allow for early events to be recorded.
* This function is called after the tracefs has been initialized,
* and we now have to create the files associated to the events.
*/
static void __trace_early_add_event_dirs(struct trace_array *tr)
{
struct trace_event_file *file;
int ret;
list_for_each_entry(file, &tr->events, list) {
ret = event_create_dir(tr->event_dir, file);
if (ret < 0)
pr_warn("Could not create directory for event %s\n",
trace_event_name(file->event_call));
}
}
/*
* For early boot up, the top trace array and the trace arrays created
* by boot-time tracing require to have a list of events that can be
* enabled. This must be done before the filesystem is set up in order
* to allow events to be traced early.
*/
void __trace_early_add_events(struct trace_array *tr)
{
struct trace_event_call *call;
int ret;
list_for_each_entry(call, &ftrace_events, list) {
/* Early boot up should not have any modules loaded */
if (!(call->flags & TRACE_EVENT_FL_DYNAMIC) &&
WARN_ON_ONCE(call->module))
continue;
ret = __trace_early_add_new_event(call, tr);
if (ret < 0)
pr_warn("Could not create early event %s\n",
trace_event_name(call));
}
}
/* Remove the event directory structure for a trace directory. */
static void
__trace_remove_event_dirs(struct trace_array *tr)
{
struct trace_event_file *file, *next;
list_for_each_entry_safe(file, next, &tr->events, list)
remove_event_file_dir(file);
}
static void __add_event_to_tracers(struct trace_event_call *call)
{
struct trace_array *tr;
list_for_each_entry(tr, &ftrace_trace_arrays, list)
__trace_add_new_event(call, tr);
}
extern struct trace_event_call *__start_ftrace_events[];
extern struct trace_event_call *__stop_ftrace_events[];
static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
static __init int setup_trace_event(char *str)
{
strscpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
trace_set_ring_buffer_expanded(NULL);
disable_tracing_selftest("running event tracing");
return 1;
}
__setup("trace_event=", setup_trace_event);
static int events_callback(const char *name, umode_t *mode, void **data,
const struct file_operations **fops)
{
if (strcmp(name, "enable") == 0) {
*mode = TRACE_MODE_WRITE;
*fops = &ftrace_tr_enable_fops;
return 1;
}
if (strcmp(name, "header_page") == 0) {
*mode = TRACE_MODE_READ;
*fops = &ftrace_show_header_page_fops;
} else if (strcmp(name, "header_event") == 0) {
*mode = TRACE_MODE_READ;
*fops = &ftrace_show_header_event_fops;
} else
return 0;
return 1;
}
/* Expects to have event_mutex held when called */
static int
create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
{
struct eventfs_inode *e_events;
struct dentry *entry;
int nr_entries;
static struct eventfs_entry events_entries[] = {
{
.name = "enable",
.callback = events_callback,
},
{
.name = "header_page",
.callback = events_callback,
},
{
.name = "header_event",
.callback = events_callback,
},
};
entry = trace_create_file("set_event", TRACE_MODE_WRITE, parent,
tr, &ftrace_set_event_fops);
if (!entry)
return -ENOMEM;
nr_entries = ARRAY_SIZE(events_entries);
e_events = eventfs_create_events_dir("events", parent, events_entries,
nr_entries, tr);
if (IS_ERR(e_events)) {
pr_warn("Could not create tracefs 'events' directory\n");
return -ENOMEM;
}
/* There are not as crucial, just warn if they are not created */
trace_create_file("set_event_pid", TRACE_MODE_WRITE, parent,
tr, &ftrace_set_event_pid_fops);
trace_create_file("set_event_notrace_pid",
TRACE_MODE_WRITE, parent, tr,
&ftrace_set_event_notrace_pid_fops);
tr->event_dir = e_events;
return 0;
}
/**
* event_trace_add_tracer - add a instance of a trace_array to events
* @parent: The parent dentry to place the files/directories for events in
* @tr: The trace array associated with these events
*
* When a new instance is created, it needs to set up its events
* directory, as well as other files associated with events. It also
* creates the event hierarchy in the @parent/events directory.
*
* Returns 0 on success.
*
* Must be called with event_mutex held.
*/
int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
{
int ret;
lockdep_assert_held(&event_mutex);
ret = create_event_toplevel_files(parent, tr);
if (ret)
goto out;
down_write(&trace_event_sem);
/* If tr already has the event list, it is initialized in early boot. */
if (unlikely(!list_empty(&tr->events)))
__trace_early_add_event_dirs(tr);
else
__trace_add_event_dirs(tr);
up_write(&trace_event_sem);
out:
return ret;
}
/*
* The top trace array already had its file descriptors created.
* Now the files themselves need to be created.
*/
static __init int
early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
{
int ret;
mutex_lock(&event_mutex);
ret = create_event_toplevel_files(parent, tr);
if (ret)
goto out_unlock;
down_write(&trace_event_sem);
__trace_early_add_event_dirs(tr);
up_write(&trace_event_sem);
out_unlock:
mutex_unlock(&event_mutex);
return ret;
}
/* Must be called with event_mutex held */
int event_trace_del_tracer(struct trace_array *tr)
{
lockdep_assert_held(&event_mutex);
/* Disable any event triggers and associated soft-disabled events */
clear_event_triggers(tr);
/* Clear the pid list */
__ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
/* Disable any running events */
__ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
/* Make sure no more events are being executed */
tracepoint_synchronize_unregister();
down_write(&trace_event_sem);
__trace_remove_event_dirs(tr);
eventfs_remove_events_dir(tr->event_dir);
up_write(&trace_event_sem);
tr->event_dir = NULL;
return 0;
}
static __init int event_trace_memsetup(void)
{
field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
return 0;
}
__init void
early_enable_events(struct trace_array *tr, char *buf, bool disable_first)
{
char *token;
int ret;
while (true) {
token = strsep(&buf, ",");
if (!token)
break;
if (*token) {
/* Restarting syscalls requires that we stop them first */
if (disable_first)
ftrace_set_clr_event(tr, token, 0);
ret = ftrace_set_clr_event(tr, token, 1);
if (ret)
pr_warn("Failed to enable trace event: %s\n", token);
}
/* Put back the comma to allow this to be called again */
if (buf)
*(buf - 1) = ',';
}
}
static __init int event_trace_enable(void)
{
struct trace_array *tr = top_trace_array();
struct trace_event_call **iter, *call;
int ret;
if (!tr)
return -ENODEV;
for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
call = *iter;
ret = event_init(call);
if (!ret)
list_add(&call->list, &ftrace_events);
}
register_trigger_cmds();
/*
* We need the top trace array to have a working set of trace
* points at early init, before the debug files and directories
* are created. Create the file entries now, and attach them
* to the actual file dentries later.
*/
__trace_early_add_events(tr);
early_enable_events(tr, bootup_event_buf, false);
trace_printk_start_comm();
register_event_cmds();
return 0;
}
/*
* event_trace_enable() is called from trace_event_init() first to
* initialize events and perhaps start any events that are on the
* command line. Unfortunately, there are some events that will not
* start this early, like the system call tracepoints that need
* to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
* event_trace_enable() is called before pid 1 starts, and this flag
* is never set, making the syscall tracepoint never get reached, but
* the event is enabled regardless (and not doing anything).
*/
static __init int event_trace_enable_again(void)
{
struct trace_array *tr;
tr = top_trace_array();
if (!tr)
return -ENODEV;
early_enable_events(tr, bootup_event_buf, true);
return 0;
}
early_initcall(event_trace_enable_again);
/* Init fields which doesn't related to the tracefs */
static __init int event_trace_init_fields(void)
{
if (trace_define_generic_fields())
pr_warn("tracing: Failed to allocated generic fields");
if (trace_define_common_fields())
pr_warn("tracing: Failed to allocate common fields");
return 0;
}
__init int event_trace_init(void)
{
struct trace_array *tr;
int ret;
tr = top_trace_array();
if (!tr)
return -ENODEV;
trace_create_file("available_events", TRACE_MODE_READ,
NULL, tr, &ftrace_avail_fops);
ret = early_event_add_tracer(NULL, tr);
if (ret)
return ret;
#ifdef CONFIG_MODULES
ret = register_module_notifier(&trace_module_nb);
if (ret)
pr_warn("Failed to register trace events module notifier\n");
#endif
eventdir_initialized = true;
return 0;
}
void __init trace_event_init(void)
{
event_trace_memsetup();
init_ftrace_syscalls();
event_trace_enable();
event_trace_init_fields();
}
#ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
static DEFINE_SPINLOCK(test_spinlock);
static DEFINE_SPINLOCK(test_spinlock_irq);
static DEFINE_MUTEX(test_mutex);
static __init void test_work(struct work_struct *dummy)
{
spin_lock(&test_spinlock);
spin_lock_irq(&test_spinlock_irq);
udelay(1);
spin_unlock_irq(&test_spinlock_irq);
spin_unlock(&test_spinlock);
mutex_lock(&test_mutex);
msleep(1);
mutex_unlock(&test_mutex);
}
static __init int event_test_thread(void *unused)
{
void *test_malloc;
test_malloc = kmalloc(1234, GFP_KERNEL);
if (!test_malloc)
pr_info("failed to kmalloc\n");
schedule_on_each_cpu(test_work);
kfree(test_malloc);
set_current_state(TASK_INTERRUPTIBLE);
while (!kthread_should_stop()) {
schedule();
set_current_state(TASK_INTERRUPTIBLE);
}
__set_current_state(TASK_RUNNING);
return 0;
}
/*
* Do various things that may trigger events.
*/
static __init void event_test_stuff(void)
{
struct task_struct *test_thread;
test_thread = kthread_run(event_test_thread, NULL, "test-events");
msleep(1);
kthread_stop(test_thread);
}
/*
* For every trace event defined, we will test each trace point separately,
* and then by groups, and finally all trace points.
*/
static __init void event_trace_self_tests(void)
{
struct trace_subsystem_dir *dir;
struct trace_event_file *file;
struct trace_event_call *call;
struct event_subsystem *system;
struct trace_array *tr;
int ret;
tr = top_trace_array();
if (!tr)
return;
pr_info("Running tests on trace events:\n");
list_for_each_entry(file, &tr->events, list) {
call = file->event_call;
/* Only test those that have a probe */
if (!call->class || !call->class->probe)
continue;
/*
* Testing syscall events here is pretty useless, but
* we still do it if configured. But this is time consuming.
* What we really need is a user thread to perform the
* syscalls as we test.
*/
#ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
if (call->class->system &&
strcmp(call->class->system, "syscalls") == 0)
continue;
#endif
pr_info("Testing event %s: ", trace_event_name(call));
/*
* If an event is already enabled, someone is using
* it and the self test should not be on.
*/
if (file->flags & EVENT_FILE_FL_ENABLED) {
pr_warn("Enabled event during self test!\n");
WARN_ON_ONCE(1);
continue;
}
ftrace_event_enable_disable(file, 1);
event_test_stuff();
ftrace_event_enable_disable(file, 0);
pr_cont("OK\n");
}
/* Now test at the sub system level */
pr_info("Running tests on trace event systems:\n");
list_for_each_entry(dir, &tr->systems, list) {
system = dir->subsystem;
/* the ftrace system is special, skip it */
if (strcmp(system->name, "ftrace") == 0)
continue;
pr_info("Testing event system %s: ", system->name);
ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
if (WARN_ON_ONCE(ret)) {
pr_warn("error enabling system %s\n",
system->name);
continue;
}
event_test_stuff();
ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
if (WARN_ON_ONCE(ret)) {
pr_warn("error disabling system %s\n",
system->name);
continue;
}
pr_cont("OK\n");
}
/* Test with all events enabled */
pr_info("Running tests on all trace events:\n");
pr_info("Testing all events: ");
ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
if (WARN_ON_ONCE(ret)) {
pr_warn("error enabling all events\n");
return;
}
event_test_stuff();
/* reset sysname */
ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
if (WARN_ON_ONCE(ret)) {
pr_warn("error disabling all events\n");
return;
}
pr_cont("OK\n");
}
#ifdef CONFIG_FUNCTION_TRACER
static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
static struct trace_event_file event_trace_file __initdata;
static void __init
function_test_events_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *regs)
{
struct trace_buffer *buffer;
struct ring_buffer_event *event;
struct ftrace_entry *entry;
unsigned int trace_ctx;
long disabled;
int cpu;
trace_ctx = tracing_gen_ctx();
preempt_disable_notrace();
cpu = raw_smp_processor_id();
disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
if (disabled != 1)
goto out;
event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
TRACE_FN, sizeof(*entry),
trace_ctx);
if (!event)
goto out;
entry = ring_buffer_event_data(event);
entry->ip = ip;
entry->parent_ip = parent_ip;
event_trigger_unlock_commit(&event_trace_file, buffer, event,
entry, trace_ctx);
out:
atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
preempt_enable_notrace();
}
static struct ftrace_ops trace_ops __initdata =
{
.func = function_test_events_call,
};
static __init void event_trace_self_test_with_function(void)
{
int ret;
event_trace_file.tr = top_trace_array();
if (WARN_ON(!event_trace_file.tr))
return;
ret = register_ftrace_function(&trace_ops);
if (WARN_ON(ret < 0)) {
pr_info("Failed to enable function tracer for event tests\n");
return;
}
pr_info("Running tests again, along with the function tracer\n");
event_trace_self_tests();
unregister_ftrace_function(&trace_ops);
}
#else
static __init void event_trace_self_test_with_function(void)
{
}
#endif
static __init int event_trace_self_tests_init(void)
{
if (!tracing_selftest_disabled) {
event_trace_self_tests();
event_trace_self_test_with_function();
}
return 0;
}
late_initcall(event_trace_self_tests_init);
#endif
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