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kernel_optimize_test/kernel/trace/trace_events.c
Steven Rostedt (Red Hat) e57cbaf0eb tracing: Do not have 'comm' filter override event 'comm' field 
Commit 9f61668073 "tracing: Allow triggers to filter for CPU ids and
process names" added a 'comm' filter that will filter events based on the
current tasks struct 'comm'. But this now hides the ability to filter events
that have a 'comm' field too. For example, sched_migrate_task trace event.
That has a 'comm' field of the task to be migrated.

 echo 'comm == "bash"' > events/sched_migrate_task/filter

will now filter all sched_migrate_task events for tasks named "bash" that
migrates other tasks (in interrupt context), instead of seeing when "bash"
itself gets migrated.

This fix requires a couple of changes.

1) Change the look up order for filter predicates to look at the events
   fields before looking at the generic filters.

2) Instead of basing the filter function off of the "comm" name, have the
   generic "comm" filter have its own filter_type (FILTER_COMM). Test
   against the type instead of the name to assign the filter function.

3) Add a new "COMM" filter that works just like "comm" but will filter based
   on the current task, even if the trace event contains a "comm" field.

Do the same for "cpu" field, adding a FILTER_CPU and a filter "CPU".

Cc: stable@vger.kernel.org # v4.3+
Fixes: 9f61668073 "tracing: Allow triggers to filter for CPU ids and process names"
Reported-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-04 09:57:10 -05:00

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/*
* 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/spinlock.h>
#include <linux/kthread.h>
#include <linux/tracefs.h>
#include <linux/uaccess.h>
#include <linux/bsearch.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 <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);
#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 list_head *
trace_get_fields(struct trace_event_call *event_call)
{
if (!event_call->class->get_fields)
return &event_call->class->fields;
return event_call->class->get_fields(event_call);
}
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)
{
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;
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);
}
EXPORT_SYMBOL_GPL(trace_define_field);
#define __generic_field(type, item, filter_type) \
ret = __trace_define_field(&ftrace_generic_fields, #type, \
#item, 0, 0, is_signed_type(type), \
filter_type); \
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); \
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(char *, COMM, FILTER_COMM);
__generic_field(char *, comm, FILTER_COMM);
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);
__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);
}
}
int trace_event_raw_init(struct trace_event_call *call)
{
int id;
id = register_trace_event(&call->event);
if (!id)
return -ENODEV;
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 *pid_list;
pid_list = rcu_dereference_sched(tr->filtered_pids);
if (!pid_list)
return false;
data = this_cpu_ptr(tr->trace_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;
local_save_flags(fbuffer->flags);
fbuffer->pc = preempt_count();
fbuffer->trace_file = trace_file;
fbuffer->event =
trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
event_call->event.type, len,
fbuffer->flags, fbuffer->pc);
if (!fbuffer->event)
return NULL;
fbuffer->entry = ring_buffer_event_data(fbuffer->event);
return fbuffer->entry;
}
EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
static DEFINE_SPINLOCK(tracepoint_iter_lock);
static void output_printk(struct trace_event_buffer *fbuffer)
{
struct trace_event_call *event_call;
struct trace_event *event;
unsigned long flags;
struct trace_iterator *iter = tracepoint_print_iter;
if (!iter)
return;
event_call = fbuffer->trace_file->event_call;
if (!event_call || !event_call->event.funcs ||
!event_call->event.funcs->trace)
return;
event = &fbuffer->trace_file->event_call->event;
spin_lock_irqsave(&tracepoint_iter_lock, flags);
trace_seq_init(&iter->seq);
iter->ent = fbuffer->entry;
event_call->event.funcs->trace(iter, 0, event);
trace_seq_putc(&iter->seq, 0);
printk("%s", iter->seq.buffer);
spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
}
void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
{
if (tracepoint_printk)
output_printk(fbuffer);
event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
fbuffer->event, fbuffer->entry,
fbuffer->flags, fbuffer->pc);
}
EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
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;
mutex_lock(&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();
mutex_unlock(&event_mutex);
}
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);
} 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);
}
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);
}
if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
/* 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) {
tracing_start_cmdline_record();
set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
}
ret = call->class->reg(call, TRACE_REG_REGISTER, file);
if (ret) {
tracing_stop_cmdline_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. */
call->flags |= TRACE_EVENT_FL_WAS_ENABLED;
}
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 int cmp_pid(const void *key, const void *elt)
{
const pid_t *search_pid = key;
const pid_t *pid = elt;
if (*search_pid == *pid)
return 0;
if (*search_pid < *pid)
return -1;
return 1;
}
static bool
check_ignore_pid(struct trace_pid_list *filtered_pids, struct task_struct *task)
{
pid_t search_pid;
pid_t *pid;
/*
* Return false, because if filtered_pids does not exist,
* all pids are good to trace.
*/
if (!filtered_pids)
return false;
search_pid = task->pid;
pid = bsearch(&search_pid, filtered_pids->pids,
filtered_pids->nr_pids, sizeof(pid_t),
cmp_pid);
if (!pid)
return true;
return false;
}
static void
event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
struct task_struct *prev, struct task_struct *next)
{
struct trace_array *tr = data;
struct trace_pid_list *pid_list;
pid_list = rcu_dereference_sched(tr->filtered_pids);
this_cpu_write(tr->trace_buffer.data->ignore_pid,
check_ignore_pid(pid_list, prev) &&
check_ignore_pid(pid_list, next));
}
static void
event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
struct task_struct *prev, struct task_struct *next)
{
struct trace_array *tr = data;
struct trace_pid_list *pid_list;
pid_list = rcu_dereference_sched(tr->filtered_pids);
this_cpu_write(tr->trace_buffer.data->ignore_pid,
check_ignore_pid(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 *pid_list;
/* Nothing to do if we are already tracing */
if (!this_cpu_read(tr->trace_buffer.data->ignore_pid))
return;
pid_list = rcu_dereference_sched(tr->filtered_pids);
this_cpu_write(tr->trace_buffer.data->ignore_pid,
check_ignore_pid(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 *pid_list;
/* Nothing to do if we are not tracing */
if (this_cpu_read(tr->trace_buffer.data->ignore_pid))
return;
pid_list = rcu_dereference_sched(tr->filtered_pids);
/* Set tracing if current is enabled */
this_cpu_write(tr->trace_buffer.data->ignore_pid,
check_ignore_pid(pid_list, current));
}
static void __ftrace_clear_event_pids(struct trace_array *tr)
{
struct trace_pid_list *pid_list;
struct trace_event_file *file;
int cpu;
pid_list = rcu_dereference_protected(tr->filtered_pids,
lockdep_is_held(&event_mutex));
if (!pid_list)
return;
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);
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->trace_buffer.data, cpu)->ignore_pid = false;
rcu_assign_pointer(tr->filtered_pids, NULL);
/* Wait till all users are no longer using pid filtering */
synchronize_sched();
free_pages((unsigned long)pid_list->pids, pid_list->order);
kfree(pid_list);
}
static void ftrace_clear_event_pids(struct trace_array *tr)
{
mutex_lock(&event_mutex);
__ftrace_clear_event_pids(tr);
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) {
tracefs_remove_recursive(dir->entry);
list_del(&dir->list);
__put_system_dir(dir);
}
}
static void remove_event_file_dir(struct trace_event_file *file)
{
struct dentry *dir = file->dir;
struct dentry *child;
if (dir) {
spin_lock(&dir->d_lock); /* probably unneeded */
list_for_each_entry(child, &dir->d_subdirs, d_child) {
if (d_really_is_positive(child)) /* probably unneeded */
d_inode(child)->i_private = NULL;
}
spin_unlock(&dir->d_lock);
tracefs_remove_recursive(dir);
}
list_del(&file->list);
remove_subsystem(file->system);
free_event_filter(file->filter);
kmem_cache_free(file_cachep, 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;
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;
ftrace_event_enable_disable(file, set);
ret = 0;
}
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;
}
static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
{
char *event = NULL, *sub = NULL, *match;
int ret;
/*
* 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);
/* 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();
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;
parser.buffer[parser.idx] = 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 *p_start(struct seq_file *m, loff_t *pos)
__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();
pid_list = rcu_dereference_sched(tr->filtered_pids);
if (!pid_list || *pos >= pid_list->nr_pids)
return NULL;
return (void *)&pid_list->pids[*pos];
}
static void p_stop(struct seq_file *m, void *p)
__releases(RCU)
{
rcu_read_unlock_sched();
mutex_unlock(&event_mutex);
}
static void *
p_next(struct seq_file *m, void *v, loff_t *pos)
{
struct trace_array *tr = m->private;
struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids);
(*pos)++;
if (*pos >= pid_list->nr_pids)
return NULL;
return (void *)&pid_list->pids[*pos];
}
static int p_show(struct seq_file *m, void *v)
{
pid_t *pid = v;
seq_printf(m, "%d\n", *pid);
return 0;
}
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_data(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;
ret = tracing_update_buffers();
if (ret < 0)
return ret;
switch (val) {
case 0:
case 1:
ret = -ENODEV;
mutex_lock(&event_mutex);
file = event_file_data(filp);
if (likely(file))
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 (!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();
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_call *call = event_file_data(m->private);
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_call *call = event_file_data(m->private);
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 (!strncmp(field->type, "__data_loc", 10))
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
seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
(int)(array_descriptor - field->type),
field->type, field->name,
array_descriptor, field->offset,
field->size, !!field->is_signed);
return 0;
}
static void *f_start(struct seq_file *m, loff_t *pos)
{
void *p = (void *)FORMAT_HEADER;
loff_t l = 0;
/* ->stop() is called even if ->start() fails */
mutex_lock(&event_mutex);
if (!event_file_data(m->private))
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;
ret = seq_open(file, &trace_format_seq_ops);
if (ret < 0)
return ret;
m = file->private_data;
m->private = file;
return 0;
}
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 (*ppos)
return 0;
if (unlikely(!id))
return -ENODEV;
len = sprintf(buf, "%d\n", id);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
}
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_data(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_data(filp);
if (file)
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 event_subsystem *system = NULL;
struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */
struct trace_array *tr;
int ret;
if (tracing_is_disabled())
return -ENODEV;
/* Make sure the system still exists */
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
list_for_each_entry(dir, &tr->systems, list) {
if (dir == inode->i_private) {
/* Don't open systems with no events */
if (dir->nr_events) {
__get_system_dir(dir);
system = dir->subsystem;
}
goto exit_loop;
}
}
}
exit_loop:
mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
if (!system)
return -ENODEV;
/* Some versions of gcc think dir can be uninitialized here */
WARN_ON(!dir);
/* 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;
if (tracing_is_disabled())
return -ENODEV;
if (trace_array_get(tr) < 0)
return -ENODEV;
/* Make a temporary dir that has no system but points to tr */
dir = kzalloc(sizeof(*dir), GFP_KERNEL);
if (!dir) {
trace_array_put(tr);
return -ENOMEM;
}
dir->tr = tr;
ret = tracing_open_generic(inode, filp);
if (ret < 0) {
trace_array_put(tr);
kfree(dir);
return ret;
}
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(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
{
int (*func)(struct trace_seq *s) = 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);
func(s);
r = simple_read_from_buffer(ubuf, cnt, ppos,
s->buffer, trace_seq_used(s));
kfree(s);
return r;
}
static int max_pids(struct trace_pid_list *pid_list)
{
return (PAGE_SIZE << pid_list->order) / sizeof(pid_t);
}
static void ignore_task_cpu(void *data)
{
struct trace_array *tr = data;
struct trace_pid_list *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));
this_cpu_write(tr->trace_buffer.data->ignore_pid,
check_ignore_pid(pid_list, current));
}
static ssize_t
ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct seq_file *m = filp->private_data;
struct trace_array *tr = m->private;
struct trace_pid_list *filtered_pids = NULL;
struct trace_pid_list *pid_list = NULL;
struct trace_event_file *file;
struct trace_parser parser;
unsigned long val;
loff_t this_pos;
ssize_t read = 0;
ssize_t ret = 0;
pid_t pid;
int i;
if (!cnt)
return 0;
ret = tracing_update_buffers();
if (ret < 0)
return ret;
if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
return -ENOMEM;
mutex_lock(&event_mutex);
/*
* Load as many pids into the array before doing a
* swap from the tr->filtered_pids to the new list.
*/
while (cnt > 0) {
this_pos = 0;
ret = trace_get_user(&parser, ubuf, cnt, &this_pos);
if (ret < 0 || !trace_parser_loaded(&parser))
break;
read += ret;
ubuf += ret;
cnt -= ret;
parser.buffer[parser.idx] = 0;
ret = -EINVAL;
if (kstrtoul(parser.buffer, 0, &val))
break;
if (val > INT_MAX)
break;
pid = (pid_t)val;
ret = -ENOMEM;
if (!pid_list) {
pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
if (!pid_list)
break;
filtered_pids = rcu_dereference_protected(tr->filtered_pids,
lockdep_is_held(&event_mutex));
if (filtered_pids)
pid_list->order = filtered_pids->order;
else
pid_list->order = 0;
pid_list->pids = (void *)__get_free_pages(GFP_KERNEL,
pid_list->order);
if (!pid_list->pids)
break;
if (filtered_pids) {
pid_list->nr_pids = filtered_pids->nr_pids;
memcpy(pid_list->pids, filtered_pids->pids,
pid_list->nr_pids * sizeof(pid_t));
} else
pid_list->nr_pids = 0;
}
if (pid_list->nr_pids >= max_pids(pid_list)) {
pid_t *pid_page;
pid_page = (void *)__get_free_pages(GFP_KERNEL,
pid_list->order + 1);
if (!pid_page)
break;
memcpy(pid_page, pid_list->pids,
pid_list->nr_pids * sizeof(pid_t));
free_pages((unsigned long)pid_list->pids, pid_list->order);
pid_list->order++;
pid_list->pids = pid_page;
}
pid_list->pids[pid_list->nr_pids++] = pid;
trace_parser_clear(&parser);
ret = 0;
}
trace_parser_put(&parser);
if (ret < 0) {
if (pid_list)
free_pages((unsigned long)pid_list->pids, pid_list->order);
kfree(pid_list);
mutex_unlock(&event_mutex);
return ret;
}
if (!pid_list) {
mutex_unlock(&event_mutex);
return ret;
}
sort(pid_list->pids, pid_list->nr_pids, sizeof(pid_t), cmp_pid, NULL);
/* Remove duplicates */
for (i = 1; i < pid_list->nr_pids; i++) {
int start = i;
while (i < pid_list->nr_pids &&
pid_list->pids[i - 1] == pid_list->pids[i])
i++;
if (start != i) {
if (i < pid_list->nr_pids) {
memmove(&pid_list->pids[start], &pid_list->pids[i],
(pid_list->nr_pids - i) * sizeof(pid_t));
pid_list->nr_pids -= i - start;
i = start;
} else
pid_list->nr_pids = start;
}
}
rcu_assign_pointer(tr->filtered_pids, pid_list);
list_for_each_entry(file, &tr->events, list) {
set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
}
if (filtered_pids) {
synchronize_sched();
free_pages((unsigned long)filtered_pids->pids, filtered_pids->order);
kfree(filtered_pids);
} else {
/*
* 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);
}
/*
* 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);
mutex_unlock(&event_mutex);
ret = read;
*ppos += read;
return ret;
}
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_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 = p_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_enable_fops = {
.open = tracing_open_generic,
.read = event_enable_read,
.write = event_enable_write,
.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,
};
static const struct file_operations ftrace_event_id_fops = {
.read = event_id_read,
.llseek = default_llseek,
};
static const struct file_operations ftrace_event_filter_fops = {
.open = tracing_open_generic,
.read = event_filter_read,
.write = event_filter_write,
.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_fops = {
.open = tracing_open_generic,
.read = show_header,
.llseek = default_llseek,
};
static int
ftrace_event_open(struct inode *inode, struct file *file,
const struct seq_operations *seq_ops)
{
struct seq_file *m;
int 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;
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;
if (trace_array_get(tr) < 0)
return -ENODEV;
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;
if (trace_array_get(tr) < 0)
return -ENODEV;
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC))
ftrace_clear_event_pids(tr);
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 = NULL;
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 struct dentry *
event_subsystem_dir(struct trace_array *tr, const char *name,
struct trace_event_file *file, struct dentry *parent)
{
struct trace_subsystem_dir *dir;
struct event_subsystem *system;
struct dentry *entry;
/* 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->entry;
}
}
/* Now see if the system itself exists. */
list_for_each_entry(system, &event_subsystems, list) {
if (strcmp(system->name, name) == 0)
break;
}
/* Reset system variable when not found */
if (&system->list == &event_subsystems)
system = NULL;
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);
dir->entry = tracefs_create_dir(name, parent);
if (!dir->entry) {
pr_warn("Failed to create system directory %s\n", name);
__put_system(system);
goto out_free;
}
dir->tr = tr;
dir->ref_count = 1;
dir->nr_events = 1;
dir->subsystem = system;
file->system = dir;
entry = tracefs_create_file("filter", 0644, dir->entry, dir,
&ftrace_subsystem_filter_fops);
if (!entry) {
kfree(system->filter);
system->filter = NULL;
pr_warn("Could not create tracefs '%s/filter' entry\n", name);
}
trace_create_file("enable", 0644, dir->entry, dir,
&ftrace_system_enable_fops);
list_add(&dir->list, &tr->systems);
return dir->entry;
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_create_dir(struct dentry *parent, struct trace_event_file *file)
{
struct trace_event_call *call = file->event_call;
struct trace_array *tr = file->tr;
struct list_head *head;
struct dentry *d_events;
const char *name;
int ret;
/*
* If the trace point header did not define TRACE_SYSTEM
* then the system would be called "TRACE_SYSTEM".
*/
if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
d_events = event_subsystem_dir(tr, call->class->system, file, parent);
if (!d_events)
return -ENOMEM;
} else
d_events = parent;
name = trace_event_name(call);
file->dir = tracefs_create_dir(name, d_events);
if (!file->dir) {
pr_warn("Could not create tracefs '%s' directory\n", name);
return -1;
}
if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
trace_create_file("enable", 0644, file->dir, file,
&ftrace_enable_fops);
#ifdef CONFIG_PERF_EVENTS
if (call->event.type && call->class->reg)
trace_create_file("id", 0444, file->dir,
(void *)(long)call->event.type,
&ftrace_event_id_fops);
#endif
/*
* 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)) {
ret = call->class->define_fields(call);
if (ret < 0) {
pr_warn("Could not initialize trace point events/%s\n",
name);
return -1;
}
}
trace_create_file("filter", 0644, file->dir, file,
&ftrace_event_filter_fops);
trace_create_file("trigger", 0644, file->dir, file,
&event_trigger_fops);
trace_create_file("format", 0444, file->dir, call,
&ftrace_event_format_fops);
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;
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);
call->mod = mod;
return 0;
}
static char *enum_replace(char *ptr, struct trace_enum_map *map, int len)
{
int rlen;
int elen;
/* Find the length of the enum value as a string */
elen = snprintf(ptr, 0, "%ld", map->enum_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->enum_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_enum_map *map)
{
char *ptr;
int quote = 0;
int len = strlen(map->enum_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->enum_string, ptr, len) == 0 &&
!isalnum(ptr[len]) && ptr[len] != '_') {
ptr = enum_replace(ptr, map, len);
/* Hmm, enum string smaller than value */
if (WARN_ON_ONCE(!ptr))
return;
/*
* No need to decrement here, as enum_replace()
* returns the pointer to the character passed
* the enum, and two enums 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;
}
}
}
void trace_event_enum_update(struct trace_enum_map **map, int len)
{
struct trace_event_call *call, *p;
const char *last_system = NULL;
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) {
last_i = 0;
last_system = call->class->system;
}
for (i = last_i; i < len; i++) {
if (call->class->system == map[i]->system) {
/* Save the first system if need be */
if (!last_i)
last_i = i;
update_event_printk(call, map[i]);
}
}
}
up_write(&trace_event_sem);
}
static struct trace_event_file *
trace_create_new_event(struct trace_event_call *call,
struct trace_array *tr)
{
struct trace_event_file *file;
file = kmem_cache_alloc(file_cachep, GFP_TRACE);
if (!file)
return NULL;
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);
return file;
}
/* 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);
if (!file)
return -ENOMEM;
return event_create_dir(tr->event_dir, file);
}
/*
* Just create a decriptor for early init. A descriptor is required
* for enabling events at boot. We want to enable events before
* the filesystem is initialized.
*/
static __init int
__trace_early_add_new_event(struct trace_event_call *call,
struct trace_array *tr)
{
struct trace_event_file *file;
file = trace_create_new_event(call, tr);
if (!file)
return -ENOMEM;
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;
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
ret = __register_event(call, NULL);
if (ret >= 0)
__add_event_to_tracers(call);
mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
return ret;
}
/*
* 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)
return -EBUSY;
/*
* 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;
}
/* Remove an event_call */
int trace_remove_event_call(struct trace_event_call *call)
{
int ret;
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
down_write(&trace_event_sem);
ret = probe_remove_event_call(call);
up_write(&trace_event_sem);
mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
return ret;
}
#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;
bool clear_trace = false;
down_write(&trace_event_sem);
list_for_each_entry_safe(call, p, &ftrace_events, list) {
if (call->mod == mod) {
if (call->flags & TRACE_EVENT_FL_WAS_ENABLED)
clear_trace = true;
__trace_remove_event_call(call);
}
}
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.
*/
if (clear_trace)
tracing_reset_all_online_cpus();
}
static int trace_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct module *mod = data;
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
switch (val) {
case MODULE_STATE_COMING:
trace_module_add_events(mod);
break;
case MODULE_STATE_GOING:
trace_module_remove_events(mod);
break;
}
mutex_unlock(&event_mutex);
mutex_unlock(&trace_types_lock);
return 0;
}
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));
}
}
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 || !call->class->reg)
continue;
if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
continue;
if (strcmp(event, name) == 0 &&
strcmp(system, call->class->system) == 0)
return file;
}
return NULL;
}
#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
event_enable_probe(unsigned long ip, unsigned long parent_ip, void **_data)
{
struct event_probe_data **pdata = (struct event_probe_data **)_data;
struct event_probe_data *data = *pdata;
if (!data)
return;
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_count_probe(unsigned long ip, unsigned long parent_ip, void **_data)
{
struct event_probe_data **pdata = (struct event_probe_data **)_data;
struct event_probe_data *data = *pdata;
if (!data)
return;
if (!data->count)
return;
/* Skip if the event is in a state we want to switch to */
if (data->enable == !(data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
return;
if (data->count != -1)
(data->count)--;
event_enable_probe(ip, parent_ip, _data);
}
static int
event_enable_print(struct seq_file *m, unsigned long ip,
struct ftrace_probe_ops *ops, void *_data)
{
struct event_probe_data *data = _data;
seq_printf(m, "%ps:", (void *)ip);
seq_printf(m, "%s:%s:%s",
data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
data->file->event_call->class->system,
trace_event_name(data->file->event_call));
if (data->count == -1)
seq_puts(m, ":unlimited\n");
else
seq_printf(m, ":count=%ld\n", data->count);
return 0;
}
static int
event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
void **_data)
{
struct event_probe_data **pdata = (struct event_probe_data **)_data;
struct event_probe_data *data = *pdata;
data->ref++;
return 0;
}
static void
event_enable_free(struct ftrace_probe_ops *ops, unsigned long ip,
void **_data)
{
struct event_probe_data **pdata = (struct event_probe_data **)_data;
struct event_probe_data *data = *pdata;
if (WARN_ON_ONCE(data->ref <= 0))
return;
data->ref--;
if (!data->ref) {
/* Remove the SOFT_MODE flag */
__ftrace_event_enable_disable(data->file, 0, 1);
module_put(data->file->event_call->mod);
kfree(data);
}
*pdata = NULL;
}
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 ftrace_hash *hash,
char *glob, char *cmd, char *param, int enabled)
{
struct trace_array *tr = top_trace_array();
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] == '!') {
unregister_ftrace_function_probe_func(glob+1, ops);
ret = 0;
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 = try_module_get(file->event_call->mod);
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, 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:
module_put(file->event_call->mod);
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 has 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 __init 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 requires 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.
*/
static __init 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 (WARN_ON_ONCE(call->mod))
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)
{
strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
ring_buffer_expanded = true;
tracing_selftest_disabled = true;
return 1;
}
__setup("trace_event=", setup_trace_event);
/* Expects to have event_mutex held when called */
static int
create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
{
struct dentry *d_events;
struct dentry *entry;
entry = tracefs_create_file("set_event", 0644, parent,
tr, &ftrace_set_event_fops);
if (!entry) {
pr_warn("Could not create tracefs 'set_event' entry\n");
return -ENOMEM;
}
d_events = tracefs_create_dir("events", parent);
if (!d_events) {
pr_warn("Could not create tracefs 'events' directory\n");
return -ENOMEM;
}
entry = tracefs_create_file("set_event_pid", 0644, parent,
tr, &ftrace_set_event_pid_fops);
/* ring buffer internal formats */
trace_create_file("header_page", 0444, d_events,
ring_buffer_print_page_header,
&ftrace_show_header_fops);
trace_create_file("header_event", 0444, d_events,
ring_buffer_print_entry_header,
&ftrace_show_header_fops);
trace_create_file("enable", 0644, d_events,
tr, &ftrace_tr_enable_fops);
tr->event_dir = d_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 hierachry in the @parent/events directory.
*
* Returns 0 on success.
*/
int event_trace_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_add_event_dirs(tr);
up_write(&trace_event_sem);
out_unlock:
mutex_unlock(&event_mutex);
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;
}
int event_trace_del_tracer(struct trace_array *tr)
{
mutex_lock(&event_mutex);
/* Disable any event triggers and associated soft-disabled events */
clear_event_triggers(tr);
/* Clear the pid list */
__ftrace_clear_event_pids(tr);
/* Disable any running events */
__ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
/* Access to events are within rcu_read_lock_sched() */
synchronize_sched();
down_write(&trace_event_sem);
__trace_remove_event_dirs(tr);
tracefs_remove_recursive(tr->event_dir);
up_write(&trace_event_sem);
tr->event_dir = NULL;
mutex_unlock(&event_mutex);
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;
}
static __init void
early_enable_events(struct trace_array *tr, bool disable_first)
{
char *buf = bootup_event_buf;
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);
}
/*
* 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, false);
trace_printk_start_comm();
register_event_cmds();
register_trigger_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 TIF_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, true);
return 0;
}
early_initcall(event_trace_enable_again);
static __init int event_trace_init(void)
{
struct trace_array *tr;
struct dentry *d_tracer;
struct dentry *entry;
int ret;
tr = top_trace_array();
if (!tr)
return -ENODEV;
d_tracer = tracing_init_dentry();
if (IS_ERR(d_tracer))
return 0;
entry = tracefs_create_file("available_events", 0444, d_tracer,
tr, &ftrace_avail_fops);
if (!entry)
pr_warn("Could not create tracefs 'available_events' entry\n");
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");
ret = early_event_add_tracer(d_tracer, 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
return 0;
}
void __init trace_event_init(void)
{
event_trace_memsetup();
init_ftrace_syscalls();
event_trace_enable();
}
fs_initcall(event_trace_init);
#ifdef CONFIG_FTRACE_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_array *event_tr;
static void __init
function_test_events_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs)
{
struct ring_buffer_event *event;
struct ring_buffer *buffer;
struct ftrace_entry *entry;
unsigned long flags;
long disabled;
int cpu;
int pc;
pc = preempt_count();
preempt_disable_notrace();
cpu = raw_smp_processor_id();
disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
if (disabled != 1)
goto out;
local_save_flags(flags);
event = trace_current_buffer_lock_reserve(&buffer,
TRACE_FN, sizeof(*entry),
flags, pc);
if (!event)
goto out;
entry = ring_buffer_event_data(event);
entry->ip = ip;
entry->parent_ip = parent_ip;
trace_buffer_unlock_commit(event_tr, buffer, event, flags, pc);
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,
.flags = FTRACE_OPS_FL_RECURSION_SAFE,
};
static __init void event_trace_self_test_with_function(void)
{
int ret;
event_tr = top_trace_array();
if (WARN_ON(!event_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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