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linux_old1/kernel/trace/ftrace.c

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/*
* Infrastructure for profiling code inserted by 'gcc -pg'.
*
* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
* Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
*
* Originally ported from the -rt patch by:
* Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
*
* Based on code in the latency_tracer, that is:
*
* Copyright (C) 2004-2006 Ingo Molnar
* Copyright (C) 2004 William Lee Irwin III
*/
#include <linux/stop_machine.h>
#include <linux/clocksource.h>
#include <linux/kallsyms.h>
#include <linux/seq_file.h>
#include <linux/suspend.h>
#include <linux/debugfs.h>
#include <linux/hardirq.h>
#include <linux/kthread.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/sysctl.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/hash.h>
#include <linux/rcupdate.h>
#include <trace/events/sched.h>
#include <asm/setup.h>
#include "trace_output.h"
#include "trace_stat.h"
#define FTRACE_WARN_ON(cond) \
({ \
int ___r = cond; \
if (WARN_ON(___r)) \
ftrace_kill(); \
___r; \
})
#define FTRACE_WARN_ON_ONCE(cond) \
({ \
int ___r = cond; \
if (WARN_ON_ONCE(___r)) \
ftrace_kill(); \
___r; \
})
/* hash bits for specific function selection */
#define FTRACE_HASH_BITS 7
#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
#define FTRACE_HASH_DEFAULT_BITS 10
#define FTRACE_HASH_MAX_BITS 12
/* ftrace_enabled is a method to turn ftrace on or off */
int ftrace_enabled __read_mostly;
static int last_ftrace_enabled;
/* Quick disabling of function tracer. */
int function_trace_stop;
/* List for set_ftrace_pid's pids. */
LIST_HEAD(ftrace_pids);
struct ftrace_pid {
struct list_head list;
struct pid *pid;
};
/*
* ftrace_disabled is set when an anomaly is discovered.
* ftrace_disabled is much stronger than ftrace_enabled.
*/
static int ftrace_disabled __read_mostly;
static DEFINE_MUTEX(ftrace_lock);
static struct ftrace_ops ftrace_list_end __read_mostly = {
.func = ftrace_stub,
};
static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
static struct ftrace_ops global_ops;
static void
ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
/*
* Traverse the ftrace_global_list, invoking all entries. The reason that we
* can use rcu_dereference_raw() is that elements removed from this list
* are simply leaked, so there is no need to interact with a grace-period
* mechanism. The rcu_dereference_raw() calls are needed to handle
* concurrent insertions into the ftrace_global_list.
*
* Silly Alpha and silly pointer-speculation compiler optimizations!
*/
static void ftrace_global_list_func(unsigned long ip,
unsigned long parent_ip)
{
struct ftrace_ops *op;
if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
return;
trace_recursion_set(TRACE_GLOBAL_BIT);
op = rcu_dereference_raw(ftrace_global_list); /*see above*/
while (op != &ftrace_list_end) {
op->func(ip, parent_ip);
op = rcu_dereference_raw(op->next); /*see above*/
};
trace_recursion_clear(TRACE_GLOBAL_BIT);
}
static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
{
if (!test_tsk_trace_trace(current))
return;
ftrace_pid_function(ip, parent_ip);
}
static void set_ftrace_pid_function(ftrace_func_t func)
{
/* do not set ftrace_pid_function to itself! */
if (func != ftrace_pid_func)
ftrace_pid_function = func;
}
/**
* clear_ftrace_function - reset the ftrace function
*
* This NULLs the ftrace function and in essence stops
* tracing. There may be lag
*/
void clear_ftrace_function(void)
{
ftrace_trace_function = ftrace_stub;
__ftrace_trace_function = ftrace_stub;
__ftrace_trace_function_delay = ftrace_stub;
ftrace_pid_function = ftrace_stub;
}
#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
/*
* For those archs that do not test ftrace_trace_stop in their
* mcount call site, we need to do it from C.
*/
static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
{
if (function_trace_stop)
return;
__ftrace_trace_function(ip, parent_ip);
}
#endif
static void update_global_ops(void)
{
ftrace_func_t func;
/*
* If there's only one function registered, then call that
* function directly. Otherwise, we need to iterate over the
* registered callers.
*/
if (ftrace_global_list == &ftrace_list_end ||
ftrace_global_list->next == &ftrace_list_end)
func = ftrace_global_list->func;
else
func = ftrace_global_list_func;
/* If we filter on pids, update to use the pid function */
if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
global_ops.func = func;
}
static void update_ftrace_function(void)
{
ftrace_func_t func;
update_global_ops();
/*
* If we are at the end of the list and this ops is
* not dynamic, then have the mcount trampoline call
* the function directly
*/
if (ftrace_ops_list == &ftrace_list_end ||
(ftrace_ops_list->next == &ftrace_list_end &&
!(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
func = ftrace_ops_list->func;
else
func = ftrace_ops_list_func;
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
#ifdef CONFIG_DYNAMIC_FTRACE
/* do not update till all functions have been modified */
__ftrace_trace_function_delay = func;
#else
__ftrace_trace_function = func;
#endif
ftrace_trace_function = ftrace_test_stop_func;
#endif
}
static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
{
ops->next = *list;
/*
* We are entering ops into the list but another
* CPU might be walking that list. We need to make sure
* the ops->next pointer is valid before another CPU sees
* the ops pointer included into the list.
*/
rcu_assign_pointer(*list, ops);
}
static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
{
struct ftrace_ops **p;
/*
* If we are removing the last function, then simply point
* to the ftrace_stub.
*/
if (*list == ops && ops->next == &ftrace_list_end) {
*list = &ftrace_list_end;
return 0;
}
for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
if (*p == ops)
break;
if (*p != ops)
return -1;
*p = (*p)->next;
return 0;
}
static int __register_ftrace_function(struct ftrace_ops *ops)
{
if (ftrace_disabled)
return -ENODEV;
if (FTRACE_WARN_ON(ops == &global_ops))
return -EINVAL;
if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
return -EBUSY;
if (!core_kernel_data((unsigned long)ops))
ops->flags |= FTRACE_OPS_FL_DYNAMIC;
if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
int first = ftrace_global_list == &ftrace_list_end;
add_ftrace_ops(&ftrace_global_list, ops);
ops->flags |= FTRACE_OPS_FL_ENABLED;
if (first)
add_ftrace_ops(&ftrace_ops_list, &global_ops);
} else
add_ftrace_ops(&ftrace_ops_list, ops);
if (ftrace_enabled)
update_ftrace_function();
return 0;
}
static int __unregister_ftrace_function(struct ftrace_ops *ops)
{
int ret;
if (ftrace_disabled)
return -ENODEV;
if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
return -EBUSY;
if (FTRACE_WARN_ON(ops == &global_ops))
return -EINVAL;
if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
ret = remove_ftrace_ops(&ftrace_global_list, ops);
if (!ret && ftrace_global_list == &ftrace_list_end)
ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops);
if (!ret)
ops->flags &= ~FTRACE_OPS_FL_ENABLED;
} else
ret = remove_ftrace_ops(&ftrace_ops_list, ops);
if (ret < 0)
return ret;
if (ftrace_enabled)
update_ftrace_function();
/*
* Dynamic ops may be freed, we must make sure that all
* callers are done before leaving this function.
*/
if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
synchronize_sched();
return 0;
}
static void ftrace_update_pid_func(void)
{
/* Only do something if we are tracing something */
if (ftrace_trace_function == ftrace_stub)
return;
update_ftrace_function();
}
#ifdef CONFIG_FUNCTION_PROFILER
struct ftrace_profile {
struct hlist_node node;
unsigned long ip;
unsigned long counter;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
unsigned long long time;
unsigned long long time_squared;
#endif
};
struct ftrace_profile_page {
struct ftrace_profile_page *next;
unsigned long index;
struct ftrace_profile records[];
};
struct ftrace_profile_stat {
atomic_t disabled;
struct hlist_head *hash;
struct ftrace_profile_page *pages;
struct ftrace_profile_page *start;
struct tracer_stat stat;
};
#define PROFILE_RECORDS_SIZE \
(PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
#define PROFILES_PER_PAGE \
(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
static int ftrace_profile_bits __read_mostly;
static int ftrace_profile_enabled __read_mostly;
/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
static DEFINE_MUTEX(ftrace_profile_lock);
static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
#define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
static void *
function_stat_next(void *v, int idx)
{
struct ftrace_profile *rec = v;
struct ftrace_profile_page *pg;
pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
again:
if (idx != 0)
rec++;
if ((void *)rec >= (void *)&pg->records[pg->index]) {
pg = pg->next;
if (!pg)
return NULL;
rec = &pg->records[0];
if (!rec->counter)
goto again;
}
return rec;
}
static void *function_stat_start(struct tracer_stat *trace)
{
struct ftrace_profile_stat *stat =
container_of(trace, struct ftrace_profile_stat, stat);
if (!stat || !stat->start)
return NULL;
return function_stat_next(&stat->start->records[0], 0);
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/* function graph compares on total time */
static int function_stat_cmp(void *p1, void *p2)
{
struct ftrace_profile *a = p1;
struct ftrace_profile *b = p2;
if (a->time < b->time)
return -1;
if (a->time > b->time)
return 1;
else
return 0;
}
#else
/* not function graph compares against hits */
static int function_stat_cmp(void *p1, void *p2)
{
struct ftrace_profile *a = p1;
struct ftrace_profile *b = p2;
if (a->counter < b->counter)
return -1;
if (a->counter > b->counter)
return 1;
else
return 0;
}
#endif
static int function_stat_headers(struct seq_file *m)
{
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
seq_printf(m, " Function "
"Hit Time Avg s^2\n"
" -------- "
"--- ---- --- ---\n");
#else
seq_printf(m, " Function Hit\n"
" -------- ---\n");
#endif
return 0;
}
static int function_stat_show(struct seq_file *m, void *v)
{
struct ftrace_profile *rec = v;
char str[KSYM_SYMBOL_LEN];
int ret = 0;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static struct trace_seq s;
unsigned long long avg;
unsigned long long stddev;
#endif
mutex_lock(&ftrace_profile_lock);
/* we raced with function_profile_reset() */
if (unlikely(rec->counter == 0)) {
ret = -EBUSY;
goto out;
}
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
seq_printf(m, " %-30.30s %10lu", str, rec->counter);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
seq_printf(m, " ");
avg = rec->time;
do_div(avg, rec->counter);
/* Sample standard deviation (s^2) */
if (rec->counter <= 1)
stddev = 0;
else {
stddev = rec->time_squared - rec->counter * avg * avg;
/*
* Divide only 1000 for ns^2 -> us^2 conversion.
* trace_print_graph_duration will divide 1000 again.
*/
do_div(stddev, (rec->counter - 1) * 1000);
}
trace_seq_init(&s);
trace_print_graph_duration(rec->time, &s);
trace_seq_puts(&s, " ");
trace_print_graph_duration(avg, &s);
trace_seq_puts(&s, " ");
trace_print_graph_duration(stddev, &s);
trace_print_seq(m, &s);
#endif
seq_putc(m, '\n');
out:
mutex_unlock(&ftrace_profile_lock);
return ret;
}
static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
{
struct ftrace_profile_page *pg;
pg = stat->pages = stat->start;
while (pg) {
memset(pg->records, 0, PROFILE_RECORDS_SIZE);
pg->index = 0;
pg = pg->next;
}
memset(stat->hash, 0,
FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
}
int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
{
struct ftrace_profile_page *pg;
int functions;
int pages;
int i;
/* If we already allocated, do nothing */
if (stat->pages)
return 0;
stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
if (!stat->pages)
return -ENOMEM;
#ifdef CONFIG_DYNAMIC_FTRACE
functions = ftrace_update_tot_cnt;
#else
/*
* We do not know the number of functions that exist because
* dynamic tracing is what counts them. With past experience
* we have around 20K functions. That should be more than enough.
* It is highly unlikely we will execute every function in
* the kernel.
*/
functions = 20000;
#endif
pg = stat->start = stat->pages;
pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
for (i = 0; i < pages; i++) {
pg->next = (void *)get_zeroed_page(GFP_KERNEL);
if (!pg->next)
goto out_free;
pg = pg->next;
}
return 0;
out_free:
pg = stat->start;
while (pg) {
unsigned long tmp = (unsigned long)pg;
pg = pg->next;
free_page(tmp);
}
free_page((unsigned long)stat->pages);
stat->pages = NULL;
stat->start = NULL;
return -ENOMEM;
}
static int ftrace_profile_init_cpu(int cpu)
{
struct ftrace_profile_stat *stat;
int size;
stat = &per_cpu(ftrace_profile_stats, cpu);
if (stat->hash) {
/* If the profile is already created, simply reset it */
ftrace_profile_reset(stat);
return 0;
}
/*
* We are profiling all functions, but usually only a few thousand
* functions are hit. We'll make a hash of 1024 items.
*/
size = FTRACE_PROFILE_HASH_SIZE;
stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
if (!stat->hash)
return -ENOMEM;
if (!ftrace_profile_bits) {
size--;
for (; size; size >>= 1)
ftrace_profile_bits++;
}
/* Preallocate the function profiling pages */
if (ftrace_profile_pages_init(stat) < 0) {
kfree(stat->hash);
stat->hash = NULL;
return -ENOMEM;
}
return 0;
}
static int ftrace_profile_init(void)
{
int cpu;
int ret = 0;
for_each_online_cpu(cpu) {
ret = ftrace_profile_init_cpu(cpu);
if (ret)
break;
}
return ret;
}
/* interrupts must be disabled */
static struct ftrace_profile *
ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
{
struct ftrace_profile *rec;
struct hlist_head *hhd;
struct hlist_node *n;
unsigned long key;
key = hash_long(ip, ftrace_profile_bits);
hhd = &stat->hash[key];
if (hlist_empty(hhd))
return NULL;
hlist_for_each_entry_rcu(rec, n, hhd, node) {
if (rec->ip == ip)
return rec;
}
return NULL;
}
static void ftrace_add_profile(struct ftrace_profile_stat *stat,
struct ftrace_profile *rec)
{
unsigned long key;
key = hash_long(rec->ip, ftrace_profile_bits);
hlist_add_head_rcu(&rec->node, &stat->hash[key]);
}
/*
* The memory is already allocated, this simply finds a new record to use.
*/
static struct ftrace_profile *
ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
{
struct ftrace_profile *rec = NULL;
/* prevent recursion (from NMIs) */
if (atomic_inc_return(&stat->disabled) != 1)
goto out;
/*
* Try to find the function again since an NMI
* could have added it
*/
rec = ftrace_find_profiled_func(stat, ip);
if (rec)
goto out;
if (stat->pages->index == PROFILES_PER_PAGE) {
if (!stat->pages->next)
goto out;
stat->pages = stat->pages->next;
}
rec = &stat->pages->records[stat->pages->index++];
rec->ip = ip;
ftrace_add_profile(stat, rec);
out:
atomic_dec(&stat->disabled);
return rec;
}
static void
function_profile_call(unsigned long ip, unsigned long parent_ip)
{
struct ftrace_profile_stat *stat;
struct ftrace_profile *rec;
unsigned long flags;
if (!ftrace_profile_enabled)
return;
local_irq_save(flags);
stat = &__get_cpu_var(ftrace_profile_stats);
if (!stat->hash || !ftrace_profile_enabled)
goto out;
rec = ftrace_find_profiled_func(stat, ip);
if (!rec) {
rec = ftrace_profile_alloc(stat, ip);
if (!rec)
goto out;
}
rec->counter++;
out:
local_irq_restore(flags);
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static int profile_graph_entry(struct ftrace_graph_ent *trace)
{
function_profile_call(trace->func, 0);
return 1;
}
static void profile_graph_return(struct ftrace_graph_ret *trace)
{
struct ftrace_profile_stat *stat;
unsigned long long calltime;
struct ftrace_profile *rec;
unsigned long flags;
local_irq_save(flags);
stat = &__get_cpu_var(ftrace_profile_stats);
if (!stat->hash || !ftrace_profile_enabled)
goto out;
/* If the calltime was zero'd ignore it */
if (!trace->calltime)
goto out;
calltime = trace->rettime - trace->calltime;
if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
int index;
index = trace->depth;
/* Append this call time to the parent time to subtract */
if (index)
current->ret_stack[index - 1].subtime += calltime;
if (current->ret_stack[index].subtime < calltime)
calltime -= current->ret_stack[index].subtime;
else
calltime = 0;
}
rec = ftrace_find_profiled_func(stat, trace->func);
if (rec) {
rec->time += calltime;
rec->time_squared += calltime * calltime;
}
out:
local_irq_restore(flags);
}
static int register_ftrace_profiler(void)
{
return register_ftrace_graph(&profile_graph_return,
&profile_graph_entry);
}
static void unregister_ftrace_profiler(void)
{
unregister_ftrace_graph();
}
#else
static struct ftrace_ops ftrace_profile_ops __read_mostly = {
.func = function_profile_call,
};
static int register_ftrace_profiler(void)
{
return register_ftrace_function(&ftrace_profile_ops);
}
static void unregister_ftrace_profiler(void)
{
unregister_ftrace_function(&ftrace_profile_ops);
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
static ssize_t
ftrace_profile_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
unsigned long val;
int ret;
ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
if (ret)
return ret;
val = !!val;
mutex_lock(&ftrace_profile_lock);
if (ftrace_profile_enabled ^ val) {
if (val) {
ret = ftrace_profile_init();
if (ret < 0) {
cnt = ret;
goto out;
}
ret = register_ftrace_profiler();
if (ret < 0) {
cnt = ret;
goto out;
}
ftrace_profile_enabled = 1;
} else {
ftrace_profile_enabled = 0;
/*
* unregister_ftrace_profiler calls stop_machine
* so this acts like an synchronize_sched.
*/
unregister_ftrace_profiler();
}
}
out:
mutex_unlock(&ftrace_profile_lock);
*ppos += cnt;
return cnt;
}
static ssize_t
ftrace_profile_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[64]; /* big enough to hold a number */
int r;
r = sprintf(buf, "%u\n", ftrace_profile_enabled);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
static const struct file_operations ftrace_profile_fops = {
.open = tracing_open_generic,
.read = ftrace_profile_read,
.write = ftrace_profile_write,
.llseek = default_llseek,
};
/* used to initialize the real stat files */
static struct tracer_stat function_stats __initdata = {
.name = "functions",
.stat_start = function_stat_start,
.stat_next = function_stat_next,
.stat_cmp = function_stat_cmp,
.stat_headers = function_stat_headers,
.stat_show = function_stat_show
};
static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
{
struct ftrace_profile_stat *stat;
struct dentry *entry;
char *name;
int ret;
int cpu;
for_each_possible_cpu(cpu) {
stat = &per_cpu(ftrace_profile_stats, cpu);
/* allocate enough for function name + cpu number */
name = kmalloc(32, GFP_KERNEL);
if (!name) {
/*
* The files created are permanent, if something happens
* we still do not free memory.
*/
WARN(1,
"Could not allocate stat file for cpu %d\n",
cpu);
return;
}
stat->stat = function_stats;
snprintf(name, 32, "function%d", cpu);
stat->stat.name = name;
ret = register_stat_tracer(&stat->stat);
if (ret) {
WARN(1,
"Could not register function stat for cpu %d\n",
cpu);
kfree(name);
return;
}
}
entry = debugfs_create_file("function_profile_enabled", 0644,
d_tracer, NULL, &ftrace_profile_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'function_profile_enabled' entry\n");
}
#else /* CONFIG_FUNCTION_PROFILER */
static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
{
}
#endif /* CONFIG_FUNCTION_PROFILER */
static struct pid * const ftrace_swapper_pid = &init_struct_pid;
#ifdef CONFIG_DYNAMIC_FTRACE
#ifndef CONFIG_FTRACE_MCOUNT_RECORD
# error Dynamic ftrace depends on MCOUNT_RECORD
#endif
static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
struct ftrace_func_probe {
struct hlist_node node;
struct ftrace_probe_ops *ops;
unsigned long flags;
unsigned long ip;
void *data;
struct rcu_head rcu;
};
enum {
FTRACE_ENABLE_CALLS = (1 << 0),
FTRACE_DISABLE_CALLS = (1 << 1),
FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
FTRACE_START_FUNC_RET = (1 << 3),
FTRACE_STOP_FUNC_RET = (1 << 4),
};
struct ftrace_func_entry {
struct hlist_node hlist;
unsigned long ip;
};
struct ftrace_hash {
unsigned long size_bits;
struct hlist_head *buckets;
unsigned long count;
struct rcu_head rcu;
};
/*
* We make these constant because no one should touch them,
* but they are used as the default "empty hash", to avoid allocating
* it all the time. These are in a read only section such that if
* anyone does try to modify it, it will cause an exception.
*/
static const struct hlist_head empty_buckets[1];
static const struct ftrace_hash empty_hash = {
.buckets = (struct hlist_head *)empty_buckets,
};
#define EMPTY_HASH ((struct ftrace_hash *)&empty_hash)
static struct ftrace_ops global_ops = {
.func = ftrace_stub,
.notrace_hash = EMPTY_HASH,
.filter_hash = EMPTY_HASH,
};
static struct dyn_ftrace *ftrace_new_addrs;
static DEFINE_MUTEX(ftrace_regex_lock);
struct ftrace_page {
struct ftrace_page *next;
int index;
struct dyn_ftrace records[];
};
#define ENTRIES_PER_PAGE \
((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
/* estimate from running different kernels */
#define NR_TO_INIT 10000
static struct ftrace_page *ftrace_pages_start;
static struct ftrace_page *ftrace_pages;
static struct dyn_ftrace *ftrace_free_records;
static struct ftrace_func_entry *
ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
{
unsigned long key;
struct ftrace_func_entry *entry;
struct hlist_head *hhd;
struct hlist_node *n;
if (!hash->count)
return NULL;
if (hash->size_bits > 0)
key = hash_long(ip, hash->size_bits);
else
key = 0;
hhd = &hash->buckets[key];
hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
if (entry->ip == ip)
return entry;
}
return NULL;
}
static void __add_hash_entry(struct ftrace_hash *hash,
struct ftrace_func_entry *entry)
{
struct hlist_head *hhd;
unsigned long key;
if (hash->size_bits)
key = hash_long(entry->ip, hash->size_bits);
else
key = 0;
hhd = &hash->buckets[key];
hlist_add_head(&entry->hlist, hhd);
hash->count++;
}
static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
{
struct ftrace_func_entry *entry;
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
return -ENOMEM;
entry->ip = ip;
__add_hash_entry(hash, entry);
return 0;
}
static void
free_hash_entry(struct ftrace_hash *hash,
struct ftrace_func_entry *entry)
{
hlist_del(&entry->hlist);
kfree(entry);
hash->count--;
}
static void
remove_hash_entry(struct ftrace_hash *hash,
struct ftrace_func_entry *entry)
{
hlist_del(&entry->hlist);
hash->count--;
}
static void ftrace_hash_clear(struct ftrace_hash *hash)
{
struct hlist_head *hhd;
struct hlist_node *tp, *tn;
struct ftrace_func_entry *entry;
int size = 1 << hash->size_bits;
int i;
if (!hash->count)
return;
for (i = 0; i < size; i++) {
hhd = &hash->buckets[i];
hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
free_hash_entry(hash, entry);
}
FTRACE_WARN_ON(hash->count);
}
static void free_ftrace_hash(struct ftrace_hash *hash)
{
if (!hash || hash == EMPTY_HASH)
return;
ftrace_hash_clear(hash);
kfree(hash->buckets);
kfree(hash);
}
static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
{
struct ftrace_hash *hash;
hash = container_of(rcu, struct ftrace_hash, rcu);
free_ftrace_hash(hash);
}
static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
{
if (!hash || hash == EMPTY_HASH)
return;
call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
}
static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
{
struct ftrace_hash *hash;
int size;
hash = kzalloc(sizeof(*hash), GFP_KERNEL);
if (!hash)
return NULL;
size = 1 << size_bits;
hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL);
if (!hash->buckets) {
kfree(hash);
return NULL;
}
hash->size_bits = size_bits;
return hash;
}
static struct ftrace_hash *
alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
{
struct ftrace_func_entry *entry;
struct ftrace_hash *new_hash;
struct hlist_node *tp;
int size;
int ret;
int i;
new_hash = alloc_ftrace_hash(size_bits);
if (!new_hash)
return NULL;
/* Empty hash? */
if (!hash || !hash->count)
return new_hash;
size = 1 << hash->size_bits;
for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
ret = add_hash_entry(new_hash, entry->ip);
if (ret < 0)
goto free_hash;
}
}
FTRACE_WARN_ON(new_hash->count != hash->count);
return new_hash;
free_hash:
free_ftrace_hash(new_hash);
return NULL;
}
static void
ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
static void
ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
static int
ftrace_hash_move(struct ftrace_ops *ops, int enable,
struct ftrace_hash **dst, struct ftrace_hash *src)
{
struct ftrace_func_entry *entry;
struct hlist_node *tp, *tn;
struct hlist_head *hhd;
struct ftrace_hash *old_hash;
struct ftrace_hash *new_hash;
unsigned long key;
int size = src->count;
int bits = 0;
int ret;
int i;
/*
* Remove the current set, update the hash and add
* them back.
*/
ftrace_hash_rec_disable(ops, enable);
/*
* If the new source is empty, just free dst and assign it
* the empty_hash.
*/
if (!src->count) {
free_ftrace_hash_rcu(*dst);
rcu_assign_pointer(*dst, EMPTY_HASH);
/* still need to update the function records */
ret = 0;
goto out;
}
/*
* Make the hash size about 1/2 the # found
*/
for (size /= 2; size; size >>= 1)
bits++;
/* Don't allocate too much */
if (bits > FTRACE_HASH_MAX_BITS)
bits = FTRACE_HASH_MAX_BITS;
ret = -ENOMEM;
new_hash = alloc_ftrace_hash(bits);
if (!new_hash)
goto out;
size = 1 << src->size_bits;
for (i = 0; i < size; i++) {
hhd = &src->buckets[i];
hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
if (bits > 0)
key = hash_long(entry->ip, bits);
else
key = 0;
remove_hash_entry(src, entry);
__add_hash_entry(new_hash, entry);
}
}
old_hash = *dst;
rcu_assign_pointer(*dst, new_hash);
free_ftrace_hash_rcu(old_hash);
ret = 0;
out:
/*
* Enable regardless of ret:
* On success, we enable the new hash.
* On failure, we re-enable the original hash.
*/
ftrace_hash_rec_enable(ops, enable);
return ret;
}
/*
* Test the hashes for this ops to see if we want to call
* the ops->func or not.
*
* It's a match if the ip is in the ops->filter_hash or
* the filter_hash does not exist or is empty,
* AND
* the ip is not in the ops->notrace_hash.
*
* This needs to be called with preemption disabled as
* the hashes are freed with call_rcu_sched().
*/
static int
ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
{
struct ftrace_hash *filter_hash;
struct ftrace_hash *notrace_hash;
int ret;
filter_hash = rcu_dereference_raw(ops->filter_hash);
notrace_hash = rcu_dereference_raw(ops->notrace_hash);
if ((!filter_hash || !filter_hash->count ||
ftrace_lookup_ip(filter_hash, ip)) &&
(!notrace_hash || !notrace_hash->count ||
!ftrace_lookup_ip(notrace_hash, ip)))
ret = 1;
else
ret = 0;
return ret;
}
/*
* This is a double for. Do not use 'break' to break out of the loop,
* you must use a goto.
*/
#define do_for_each_ftrace_rec(pg, rec) \
for (pg = ftrace_pages_start; pg; pg = pg->next) { \
int _____i; \
for (_____i = 0; _____i < pg->index; _____i++) { \
rec = &pg->records[_____i];
#define while_for_each_ftrace_rec() \
} \
}
static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
int filter_hash,
bool inc)
{
struct ftrace_hash *hash;
struct ftrace_hash *other_hash;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
int count = 0;
int all = 0;
/* Only update if the ops has been registered */
if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
return;
/*
* In the filter_hash case:
* If the count is zero, we update all records.
* Otherwise we just update the items in the hash.
*
* In the notrace_hash case:
* We enable the update in the hash.
* As disabling notrace means enabling the tracing,
* and enabling notrace means disabling, the inc variable
* gets inversed.
*/
if (filter_hash) {
hash = ops->filter_hash;
other_hash = ops->notrace_hash;
if (!hash || !hash->count)
all = 1;
} else {
inc = !inc;
hash = ops->notrace_hash;
other_hash = ops->filter_hash;
/*
* If the notrace hash has no items,
* then there's nothing to do.
*/
if (hash && !hash->count)
return;
}
do_for_each_ftrace_rec(pg, rec) {
int in_other_hash = 0;
int in_hash = 0;
int match = 0;
if (all) {
/*
* Only the filter_hash affects all records.
* Update if the record is not in the notrace hash.
*/
if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
match = 1;
} else {
in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip);
in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip);
/*
*
*/
if (filter_hash && in_hash && !in_other_hash)
match = 1;
else if (!filter_hash && in_hash &&
(in_other_hash || !other_hash->count))
match = 1;
}
if (!match)
continue;
if (inc) {
rec->flags++;
if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
return;
} else {
if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
return;
rec->flags--;
}
count++;
/* Shortcut, if we handled all records, we are done. */
if (!all && count == hash->count)
return;
} while_for_each_ftrace_rec();
}
static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
int filter_hash)
{
__ftrace_hash_rec_update(ops, filter_hash, 0);
}
static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
int filter_hash)
{
__ftrace_hash_rec_update(ops, filter_hash, 1);
}
static void ftrace_free_rec(struct dyn_ftrace *rec)
{
rec->freelist = ftrace_free_records;
ftrace_free_records = rec;
rec->flags |= FTRACE_FL_FREE;
}
static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
{
struct dyn_ftrace *rec;
/* First check for freed records */
if (ftrace_free_records) {
rec = ftrace_free_records;
if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
FTRACE_WARN_ON_ONCE(1);
ftrace_free_records = NULL;
return NULL;
}
ftrace_free_records = rec->freelist;
memset(rec, 0, sizeof(*rec));
return rec;
}
if (ftrace_pages->index == ENTRIES_PER_PAGE) {
if (!ftrace_pages->next) {
/* allocate another page */
ftrace_pages->next =
(void *)get_zeroed_page(GFP_KERNEL);
if (!ftrace_pages->next)
return NULL;
}
ftrace_pages = ftrace_pages->next;
}
return &ftrace_pages->records[ftrace_pages->index++];
}
static struct dyn_ftrace *
ftrace_record_ip(unsigned long ip)
{
struct dyn_ftrace *rec;
if (ftrace_disabled)
return NULL;
rec = ftrace_alloc_dyn_node(ip);
if (!rec)
return NULL;
rec->ip = ip;
rec->newlist = ftrace_new_addrs;
ftrace_new_addrs = rec;
return rec;
}
static void print_ip_ins(const char *fmt, unsigned char *p)
{
int i;
printk(KERN_CONT "%s", fmt);
for (i = 0; i < MCOUNT_INSN_SIZE; i++)
printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
}
static void ftrace_bug(int failed, unsigned long ip)
{
switch (failed) {
case -EFAULT:
FTRACE_WARN_ON_ONCE(1);
pr_info("ftrace faulted on modifying ");
print_ip_sym(ip);
break;
case -EINVAL:
FTRACE_WARN_ON_ONCE(1);
pr_info("ftrace failed to modify ");
print_ip_sym(ip);
print_ip_ins(" actual: ", (unsigned char *)ip);
printk(KERN_CONT "\n");
break;
case -EPERM:
FTRACE_WARN_ON_ONCE(1);
pr_info("ftrace faulted on writing ");
print_ip_sym(ip);
break;
default:
FTRACE_WARN_ON_ONCE(1);
pr_info("ftrace faulted on unknown error ");
print_ip_sym(ip);
}
}
/* Return 1 if the address range is reserved for ftrace */
int ftrace_text_reserved(void *start, void *end)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
do_for_each_ftrace_rec(pg, rec) {
if (rec->ip <= (unsigned long)end &&
rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
return 1;
} while_for_each_ftrace_rec();
return 0;
}
static int
__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
{
unsigned long ftrace_addr;
unsigned long flag = 0UL;
ftrace_addr = (unsigned long)FTRACE_ADDR;
/*
* If we are enabling tracing:
*
* If the record has a ref count, then we need to enable it
* because someone is using it.
*
* Otherwise we make sure its disabled.
*
* If we are disabling tracing, then disable all records that
* are enabled.
*/
if (enable && (rec->flags & ~FTRACE_FL_MASK))
flag = FTRACE_FL_ENABLED;
/* If the state of this record hasn't changed, then do nothing */
if ((rec->flags & FTRACE_FL_ENABLED) == flag)
return 0;
if (flag) {
rec->flags |= FTRACE_FL_ENABLED;
return ftrace_make_call(rec, ftrace_addr);
}
rec->flags &= ~FTRACE_FL_ENABLED;
return ftrace_make_nop(NULL, rec, ftrace_addr);
}
static void ftrace_replace_code(int enable)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
int failed;
if (unlikely(ftrace_disabled))
return;
do_for_each_ftrace_rec(pg, rec) {
/* Skip over free records */
if (rec->flags & FTRACE_FL_FREE)
continue;
failed = __ftrace_replace_code(rec, enable);
if (failed) {
ftrace_bug(failed, rec->ip);
/* Stop processing */
return;
}
} while_for_each_ftrace_rec();
}
static int
ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
{
unsigned long ip;
int ret;
ip = rec->ip;
if (unlikely(ftrace_disabled))
return 0;
ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
if (ret) {
ftrace_bug(ret, ip);
return 0;
}
return 1;
}
/*
* archs can override this function if they must do something
* before the modifying code is performed.
*/
int __weak ftrace_arch_code_modify_prepare(void)
{
return 0;
}
/*
* archs can override this function if they must do something
* after the modifying code is performed.
*/
int __weak ftrace_arch_code_modify_post_process(void)
{
return 0;
}
static int __ftrace_modify_code(void *data)
{
int *command = data;
/*
* Do not call function tracer while we update the code.
* We are in stop machine, no worrying about races.
*/
function_trace_stop++;
if (*command & FTRACE_ENABLE_CALLS)
ftrace_replace_code(1);
else if (*command & FTRACE_DISABLE_CALLS)
ftrace_replace_code(0);
if (*command & FTRACE_UPDATE_TRACE_FUNC)
ftrace_update_ftrace_func(ftrace_trace_function);
if (*command & FTRACE_START_FUNC_RET)
ftrace_enable_ftrace_graph_caller();
else if (*command & FTRACE_STOP_FUNC_RET)
ftrace_disable_ftrace_graph_caller();
#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
/*
* For archs that call ftrace_test_stop_func(), we must
* wait till after we update all the function callers
* before we update the callback. This keeps different
* ops that record different functions from corrupting
* each other.
*/
__ftrace_trace_function = __ftrace_trace_function_delay;
#endif
function_trace_stop--;
return 0;
}
static void ftrace_run_update_code(int command)
{
int ret;
ret = ftrace_arch_code_modify_prepare();
FTRACE_WARN_ON(ret);
if (ret)
return;
stop_machine(__ftrace_modify_code, &command, NULL);
ret = ftrace_arch_code_modify_post_process();
FTRACE_WARN_ON(ret);
}
static ftrace_func_t saved_ftrace_func;
static int ftrace_start_up;
static int global_start_up;
static void ftrace_startup_enable(int command)
{
if (saved_ftrace_func != ftrace_trace_function) {
saved_ftrace_func = ftrace_trace_function;
command |= FTRACE_UPDATE_TRACE_FUNC;
}
if (!command || !ftrace_enabled)
return;
ftrace_run_update_code(command);
}
static int ftrace_startup(struct ftrace_ops *ops, int command)
{
bool hash_enable = true;
if (unlikely(ftrace_disabled))
return -ENODEV;
ftrace_start_up++;
command |= FTRACE_ENABLE_CALLS;
/* ops marked global share the filter hashes */
if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
ops = &global_ops;
/* Don't update hash if global is already set */
if (global_start_up)
hash_enable = false;
global_start_up++;
}
ops->flags |= FTRACE_OPS_FL_ENABLED;
if (hash_enable)
ftrace_hash_rec_enable(ops, 1);
ftrace_startup_enable(command);
return 0;
}
static void ftrace_shutdown(struct ftrace_ops *ops, int command)
{
bool hash_disable = true;
if (unlikely(ftrace_disabled))
return;
ftrace_start_up--;
/*
* Just warn in case of unbalance, no need to kill ftrace, it's not
* critical but the ftrace_call callers may be never nopped again after
* further ftrace uses.
*/
WARN_ON_ONCE(ftrace_start_up < 0);
if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
ops = &global_ops;
global_start_up--;
WARN_ON_ONCE(global_start_up < 0);
/* Don't update hash if global still has users */
if (global_start_up) {
WARN_ON_ONCE(!ftrace_start_up);
hash_disable = false;
}
}
if (hash_disable)
ftrace_hash_rec_disable(ops, 1);
if (ops != &global_ops || !global_start_up)
ops->flags &= ~FTRACE_OPS_FL_ENABLED;
if (!ftrace_start_up)
command |= FTRACE_DISABLE_CALLS;
if (saved_ftrace_func != ftrace_trace_function) {
saved_ftrace_func = ftrace_trace_function;
command |= FTRACE_UPDATE_TRACE_FUNC;
}
if (!command || !ftrace_enabled)
return;
ftrace_run_update_code(command);
}
static void ftrace_startup_sysctl(void)
{
if (unlikely(ftrace_disabled))
return;
/* Force update next time */
saved_ftrace_func = NULL;
/* ftrace_start_up is true if we want ftrace running */
if (ftrace_start_up)
ftrace_run_update_code(FTRACE_ENABLE_CALLS);
}
static void ftrace_shutdown_sysctl(void)
{
if (unlikely(ftrace_disabled))
return;
/* ftrace_start_up is true if ftrace is running */
if (ftrace_start_up)
ftrace_run_update_code(FTRACE_DISABLE_CALLS);
}
static cycle_t ftrace_update_time;
static unsigned long ftrace_update_cnt;
unsigned long ftrace_update_tot_cnt;
static int ops_traces_mod(struct ftrace_ops *ops)
{
struct ftrace_hash *hash;
hash = ops->filter_hash;
return !!(!hash || !hash->count);
}
static int ftrace_update_code(struct module *mod)
{
struct dyn_ftrace *p;
cycle_t start, stop;
unsigned long ref = 0;
/*
* When adding a module, we need to check if tracers are
* currently enabled and if they are set to trace all functions.
* If they are, we need to enable the module functions as well
* as update the reference counts for those function records.
*/
if (mod) {
struct ftrace_ops *ops;
for (ops = ftrace_ops_list;
ops != &ftrace_list_end; ops = ops->next) {
if (ops->flags & FTRACE_OPS_FL_ENABLED &&
ops_traces_mod(ops))
ref++;
}
}
start = ftrace_now(raw_smp_processor_id());
ftrace_update_cnt = 0;
while (ftrace_new_addrs) {
/* If something went wrong, bail without enabling anything */
if (unlikely(ftrace_disabled))
return -1;
p = ftrace_new_addrs;
ftrace_new_addrs = p->newlist;
p->flags = ref;
/*
* Do the initial record conversion from mcount jump
* to the NOP instructions.
*/
if (!ftrace_code_disable(mod, p)) {
ftrace_free_rec(p);
/* Game over */
break;
}
ftrace_update_cnt++;
/*
* If the tracing is enabled, go ahead and enable the record.
*
* The reason not to enable the record immediatelly is the
* inherent check of ftrace_make_nop/ftrace_make_call for
* correct previous instructions. Making first the NOP
* conversion puts the module to the correct state, thus
* passing the ftrace_make_call check.
*/
if (ftrace_start_up && ref) {
int failed = __ftrace_replace_code(p, 1);
if (failed) {
ftrace_bug(failed, p->ip);
ftrace_free_rec(p);
}
}
}
stop = ftrace_now(raw_smp_processor_id());
ftrace_update_time = stop - start;
ftrace_update_tot_cnt += ftrace_update_cnt;
return 0;
}
static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
{
struct ftrace_page *pg;
int cnt;
int i;
/* allocate a few pages */
ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
if (!ftrace_pages_start)
return -1;
/*
* Allocate a few more pages.
*
* TODO: have some parser search vmlinux before
* final linking to find all calls to ftrace.
* Then we can:
* a) know how many pages to allocate.
* and/or
* b) set up the table then.
*
* The dynamic code is still necessary for
* modules.
*/
pg = ftrace_pages = ftrace_pages_start;
cnt = num_to_init / ENTRIES_PER_PAGE;
pr_info("ftrace: allocating %ld entries in %d pages\n",
num_to_init, cnt + 1);
for (i = 0; i < cnt; i++) {
pg->next = (void *)get_zeroed_page(GFP_KERNEL);
/* If we fail, we'll try later anyway */
if (!pg->next)
break;
pg = pg->next;
}
return 0;
}
enum {
FTRACE_ITER_FILTER = (1 << 0),
FTRACE_ITER_NOTRACE = (1 << 1),
FTRACE_ITER_PRINTALL = (1 << 2),
FTRACE_ITER_HASH = (1 << 3),
FTRACE_ITER_ENABLED = (1 << 4),
};
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
struct ftrace_iterator {
loff_t pos;
loff_t func_pos;
struct ftrace_page *pg;
struct dyn_ftrace *func;
struct ftrace_func_probe *probe;
struct trace_parser parser;
struct ftrace_hash *hash;
struct ftrace_ops *ops;
int hidx;
int idx;
unsigned flags;
};
static void *
t_hash_next(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
struct hlist_node *hnd = NULL;
struct hlist_head *hhd;
(*pos)++;
iter->pos = *pos;
if (iter->probe)
hnd = &iter->probe->node;
retry:
if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
return NULL;
hhd = &ftrace_func_hash[iter->hidx];
if (hlist_empty(hhd)) {
iter->hidx++;
hnd = NULL;
goto retry;
}
if (!hnd)
hnd = hhd->first;
else {
hnd = hnd->next;
if (!hnd) {
iter->hidx++;
goto retry;
}
}
if (WARN_ON_ONCE(!hnd))
return NULL;
iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
return iter;
}
static void *t_hash_start(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
void *p = NULL;
loff_t l;
if (iter->func_pos > *pos)
return NULL;
iter->hidx = 0;
for (l = 0; l <= (*pos - iter->func_pos); ) {
p = t_hash_next(m, &l);
if (!p)
break;
}
if (!p)
return NULL;
/* Only set this if we have an item */
iter->flags |= FTRACE_ITER_HASH;
return iter;
}
static int
t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
{
struct ftrace_func_probe *rec;
rec = iter->probe;
if (WARN_ON_ONCE(!rec))
return -EIO;
if (rec->ops->print)
return rec->ops->print(m, rec->ip, rec->ops, rec->data);
seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
if (rec->data)
seq_printf(m, ":%p", rec->data);
seq_putc(m, '\n');
return 0;
}
static void *
t_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
struct ftrace_ops *ops = &global_ops;
struct dyn_ftrace *rec = NULL;
if (unlikely(ftrace_disabled))
return NULL;
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_next(m, pos);
(*pos)++;
iter->pos = iter->func_pos = *pos;
if (iter->flags & FTRACE_ITER_PRINTALL)
return t_hash_start(m, pos);
retry:
if (iter->idx >= iter->pg->index) {
if (iter->pg->next) {
iter->pg = iter->pg->next;
iter->idx = 0;
goto retry;
}
} else {
rec = &iter->pg->records[iter->idx++];
if ((rec->flags & FTRACE_FL_FREE) ||
((iter->flags & FTRACE_ITER_FILTER) &&
!(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
((iter->flags & FTRACE_ITER_NOTRACE) &&
!ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
((iter->flags & FTRACE_ITER_ENABLED) &&
!(rec->flags & ~FTRACE_FL_MASK))) {
rec = NULL;
goto retry;
}
}
if (!rec)
return t_hash_start(m, pos);
iter->func = rec;
return iter;
}
static void reset_iter_read(struct ftrace_iterator *iter)
{
iter->pos = 0;
iter->func_pos = 0;
iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
}
static void *t_start(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
struct ftrace_ops *ops = &global_ops;
void *p = NULL;
loff_t l;
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled))
return NULL;
/*
* If an lseek was done, then reset and start from beginning.
*/
if (*pos < iter->pos)
reset_iter_read(iter);
/*
* For set_ftrace_filter reading, if we have the filter
* off, we can short cut and just print out that all
* functions are enabled.
*/
if (iter->flags & FTRACE_ITER_FILTER && !ops->filter_hash->count) {
if (*pos > 0)
return t_hash_start(m, pos);
iter->flags |= FTRACE_ITER_PRINTALL;
/* reset in case of seek/pread */
iter->flags &= ~FTRACE_ITER_HASH;
return iter;
}
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_start(m, pos);
/*
* Unfortunately, we need to restart at ftrace_pages_start
* every time we let go of the ftrace_mutex. This is because
* those pointers can change without the lock.
*/
iter->pg = ftrace_pages_start;
iter->idx = 0;
for (l = 0; l <= *pos; ) {
p = t_next(m, p, &l);
if (!p)
break;
}
if (!p) {
if (iter->flags & FTRACE_ITER_FILTER)
return t_hash_start(m, pos);
return NULL;
}
return iter;
}
static void t_stop(struct seq_file *m, void *p)
{
mutex_unlock(&ftrace_lock);
}
static int t_show(struct seq_file *m, void *v)
{
struct ftrace_iterator *iter = m->private;
struct dyn_ftrace *rec;
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_show(m, iter);
if (iter->flags & FTRACE_ITER_PRINTALL) {
seq_printf(m, "#### all functions enabled ####\n");
return 0;
}
rec = iter->func;
if (!rec)
return 0;
seq_printf(m, "%ps", (void *)rec->ip);
if (iter->flags & FTRACE_ITER_ENABLED)
seq_printf(m, " (%ld)",
rec->flags & ~FTRACE_FL_MASK);
seq_printf(m, "\n");
return 0;
}
static const struct seq_operations show_ftrace_seq_ops = {
.start = t_start,
.next = t_next,
.stop = t_stop,
.show = t_show,
};
static int
ftrace_avail_open(struct inode *inode, struct file *file)
{
struct ftrace_iterator *iter;
int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
return -ENOMEM;
iter->pg = ftrace_pages_start;
ret = seq_open(file, &show_ftrace_seq_ops);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = iter;
} else {
kfree(iter);
}
return ret;
}
static int
ftrace_enabled_open(struct inode *inode, struct file *file)
{
struct ftrace_iterator *iter;
int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
return -ENOMEM;
iter->pg = ftrace_pages_start;
iter->flags = FTRACE_ITER_ENABLED;
ret = seq_open(file, &show_ftrace_seq_ops);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = iter;
} else {
kfree(iter);
}
return ret;
}
static void ftrace_filter_reset(struct ftrace_hash *hash)
{
mutex_lock(&ftrace_lock);
ftrace_hash_clear(hash);
mutex_unlock(&ftrace_lock);
}
static int
ftrace_regex_open(struct ftrace_ops *ops, int flag,
struct inode *inode, struct file *file)
{
struct ftrace_iterator *iter;
struct ftrace_hash *hash;
int ret = 0;
if (unlikely(ftrace_disabled))
return -ENODEV;
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
return -ENOMEM;
if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
kfree(iter);
return -ENOMEM;
}
if (flag & FTRACE_ITER_NOTRACE)
hash = ops->notrace_hash;
else
hash = ops->filter_hash;
iter->ops = ops;
iter->flags = flag;
if (file->f_mode & FMODE_WRITE) {
mutex_lock(&ftrace_lock);
iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
mutex_unlock(&ftrace_lock);
if (!iter->hash) {
trace_parser_put(&iter->parser);
kfree(iter);
return -ENOMEM;
}
}
mutex_lock(&ftrace_regex_lock);
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC))
ftrace_filter_reset(iter->hash);
if (file->f_mode & FMODE_READ) {
iter->pg = ftrace_pages_start;
ret = seq_open(file, &show_ftrace_seq_ops);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = iter;
} else {
/* Failed */
free_ftrace_hash(iter->hash);
trace_parser_put(&iter->parser);
kfree(iter);
}
} else
file->private_data = iter;
mutex_unlock(&ftrace_regex_lock);
return ret;
}
static int
ftrace_filter_open(struct inode *inode, struct file *file)
{
return ftrace_regex_open(&global_ops, FTRACE_ITER_FILTER,
inode, file);
}
static int
ftrace_notrace_open(struct inode *inode, struct file *file)
{
return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
inode, file);
}
static loff_t
ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
{
loff_t ret;
if (file->f_mode & FMODE_READ)
ret = seq_lseek(file, offset, origin);
else
file->f_pos = ret = 1;
return ret;
}
static int ftrace_match(char *str, char *regex, int len, int type)
{
int matched = 0;
int slen;
switch (type) {
case MATCH_FULL:
if (strcmp(str, regex) == 0)
matched = 1;
break;
case MATCH_FRONT_ONLY:
if (strncmp(str, regex, len) == 0)
matched = 1;
break;
case MATCH_MIDDLE_ONLY:
if (strstr(str, regex))
matched = 1;
break;
case MATCH_END_ONLY:
slen = strlen(str);
if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
matched = 1;
break;
}
return matched;
}
static int
enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
{
struct ftrace_func_entry *entry;
int ret = 0;
entry = ftrace_lookup_ip(hash, rec->ip);
if (not) {
/* Do nothing if it doesn't exist */
if (!entry)
return 0;
free_hash_entry(hash, entry);
} else {
/* Do nothing if it exists */
if (entry)
return 0;
ret = add_hash_entry(hash, rec->ip);
}
return ret;
}
static int
ftrace_match_record(struct dyn_ftrace *rec, char *mod,
char *regex, int len, int type)
{
char str[KSYM_SYMBOL_LEN];
char *modname;
kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
if (mod) {
/* module lookup requires matching the module */
if (!modname || strcmp(modname, mod))
return 0;
/* blank search means to match all funcs in the mod */
if (!len)
return 1;
}
return ftrace_match(str, regex, len, type);
}
static int
match_records(struct ftrace_hash *hash, char *buff,
int len, char *mod, int not)
{
unsigned search_len = 0;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
int type = MATCH_FULL;
char *search = buff;
int found = 0;
int ret;
if (len) {
type = filter_parse_regex(buff, len, &search, &not);
search_len = strlen(search);
}
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled))
goto out_unlock;
do_for_each_ftrace_rec(pg, rec) {
if (ftrace_match_record(rec, mod, search, search_len, type)) {
ret = enter_record(hash, rec, not);
if (ret < 0) {
found = ret;
goto out_unlock;
}
found = 1;
}
} while_for_each_ftrace_rec();
out_unlock:
mutex_unlock(&ftrace_lock);
return found;
}
static int
ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
{
return match_records(hash, buff, len, NULL, 0);
}
static int
ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
{
int not = 0;
/* blank or '*' mean the same */
if (strcmp(buff, "*") == 0)
buff[0] = 0;
/* handle the case of 'dont filter this module' */
if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
buff[0] = 0;
not = 1;
}
return match_records(hash, buff, strlen(buff), mod, not);
}
/*
* We register the module command as a template to show others how
* to register the a command as well.
*/
static int
ftrace_mod_callback(struct ftrace_hash *hash,
char *func, char *cmd, char *param, int enable)
{
char *mod;
int ret = -EINVAL;
/*
* cmd == 'mod' because we only registered this func
* for the 'mod' ftrace_func_command.
* But if you register one func with multiple commands,
* you can tell which command was used by the cmd
* parameter.
*/
/* we must have a module name */
if (!param)
return ret;
mod = strsep(&param, ":");
if (!strlen(mod))
return ret;
ret = ftrace_match_module_records(hash, func, mod);
if (!ret)
ret = -EINVAL;
if (ret < 0)
return ret;
return 0;
}
static struct ftrace_func_command ftrace_mod_cmd = {
.name = "mod",
.func = ftrace_mod_callback,
};
static int __init ftrace_mod_cmd_init(void)
{
return register_ftrace_command(&ftrace_mod_cmd);
}
device_initcall(ftrace_mod_cmd_init);
static void
function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
{
struct ftrace_func_probe *entry;
struct hlist_head *hhd;
struct hlist_node *n;
unsigned long key;
key = hash_long(ip, FTRACE_HASH_BITS);
hhd = &ftrace_func_hash[key];
if (hlist_empty(hhd))
return;
/*
* Disable preemption for these calls to prevent a RCU grace
* period. This syncs the hash iteration and freeing of items
* on the hash. rcu_read_lock is too dangerous here.
*/
preempt_disable_notrace();
hlist_for_each_entry_rcu(entry, n, hhd, node) {
if (entry->ip == ip)
entry->ops->func(ip, parent_ip, &entry->data);
}
preempt_enable_notrace();
}
static struct ftrace_ops trace_probe_ops __read_mostly =
{
.func = function_trace_probe_call,
};
static int ftrace_probe_registered;
static void __enable_ftrace_function_probe(void)
{
int ret;
int i;
if (ftrace_probe_registered)
return;
for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
struct hlist_head *hhd = &ftrace_func_hash[i];
if (hhd->first)
break;
}
/* Nothing registered? */
if (i == FTRACE_FUNC_HASHSIZE)
return;
ret = __register_ftrace_function(&trace_probe_ops);
if (!ret)
ret = ftrace_startup(&trace_probe_ops, 0);
ftrace_probe_registered = 1;
}
static void __disable_ftrace_function_probe(void)
{
int ret;
int i;
if (!ftrace_probe_registered)
return;
for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
struct hlist_head *hhd = &ftrace_func_hash[i];
if (hhd->first)
return;
}
/* no more funcs left */
ret = __unregister_ftrace_function(&trace_probe_ops);
if (!ret)
ftrace_shutdown(&trace_probe_ops, 0);
ftrace_probe_registered = 0;
}
static void ftrace_free_entry_rcu(struct rcu_head *rhp)
{
struct ftrace_func_probe *entry =
container_of(rhp, struct ftrace_func_probe, rcu);
if (entry->ops->free)
entry->ops->free(&entry->data);
kfree(entry);
}
int
register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
void *data)
{
struct ftrace_func_probe *entry;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
int type, len, not;
unsigned long key;
int count = 0;
char *search;
type = filter_parse_regex(glob, strlen(glob), &search, &not);
len = strlen(search);
/* we do not support '!' for function probes */
if (WARN_ON(not))
return -EINVAL;
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled))
goto out_unlock;
do_for_each_ftrace_rec(pg, rec) {
if (!ftrace_match_record(rec, NULL, search, len, type))
continue;
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
if (!entry) {
/* If we did not process any, then return error */
if (!count)
count = -ENOMEM;
goto out_unlock;
}
count++;
entry->data = data;
/*
* The caller might want to do something special
* for each function we find. We call the callback
* to give the caller an opportunity to do so.
*/
if (ops->callback) {
if (ops->callback(rec->ip, &entry->data) < 0) {
/* caller does not like this func */
kfree(entry);
continue;
}
}
entry->ops = ops;
entry->ip = rec->ip;
key = hash_long(entry->ip, FTRACE_HASH_BITS);
hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
} while_for_each_ftrace_rec();
__enable_ftrace_function_probe();
out_unlock:
mutex_unlock(&ftrace_lock);
return count;
}
enum {
PROBE_TEST_FUNC = 1,
PROBE_TEST_DATA = 2
};
static void
__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
void *data, int flags)
{
struct ftrace_func_probe *entry;
struct hlist_node *n, *tmp;
char str[KSYM_SYMBOL_LEN];
int type = MATCH_FULL;
int i, len = 0;
char *search;
if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
glob = NULL;
else if (glob) {
int not;
type = filter_parse_regex(glob, strlen(glob), &search, &not);
len = strlen(search);
/* we do not support '!' for function probes */
if (WARN_ON(not))
return;
}
mutex_lock(&ftrace_lock);
for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
struct hlist_head *hhd = &ftrace_func_hash[i];
hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
/* break up if statements for readability */
if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
continue;
if ((flags & PROBE_TEST_DATA) && entry->data != data)
continue;
/* do this last, since it is the most expensive */
if (glob) {
kallsyms_lookup(entry->ip, NULL, NULL,
NULL, str);
if (!ftrace_match(str, glob, len, type))
continue;
}
hlist_del(&entry->node);
call_rcu(&entry->rcu, ftrace_free_entry_rcu);
}
}
__disable_ftrace_function_probe();
mutex_unlock(&ftrace_lock);
}
void
unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
void *data)
{
__unregister_ftrace_function_probe(glob, ops, data,
PROBE_TEST_FUNC | PROBE_TEST_DATA);
}
void
unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
{
__unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
}
void unregister_ftrace_function_probe_all(char *glob)
{
__unregister_ftrace_function_probe(glob, NULL, NULL, 0);
}
static LIST_HEAD(ftrace_commands);
static DEFINE_MUTEX(ftrace_cmd_mutex);
int register_ftrace_command(struct ftrace_func_command *cmd)
{
struct ftrace_func_command *p;
int ret = 0;
mutex_lock(&ftrace_cmd_mutex);
list_for_each_entry(p, &ftrace_commands, list) {
if (strcmp(cmd->name, p->name) == 0) {
ret = -EBUSY;
goto out_unlock;
}
}
list_add(&cmd->list, &ftrace_commands);
out_unlock:
mutex_unlock(&ftrace_cmd_mutex);
return ret;
}
int unregister_ftrace_command(struct ftrace_func_command *cmd)
{
struct ftrace_func_command *p, *n;
int ret = -ENODEV;
mutex_lock(&ftrace_cmd_mutex);
list_for_each_entry_safe(p, n, &ftrace_commands, list) {
if (strcmp(cmd->name, p->name) == 0) {
ret = 0;
list_del_init(&p->list);
goto out_unlock;
}
}
out_unlock:
mutex_unlock(&ftrace_cmd_mutex);
return ret;
}
static int ftrace_process_regex(struct ftrace_hash *hash,
char *buff, int len, int enable)
{
char *func, *command, *next = buff;
struct ftrace_func_command *p;
int ret = -EINVAL;
func = strsep(&next, ":");
if (!next) {
ret = ftrace_match_records(hash, func, len);
if (!ret)
ret = -EINVAL;
if (ret < 0)
return ret;
return 0;
}
/* command found */
command = strsep(&next, ":");
mutex_lock(&ftrace_cmd_mutex);
list_for_each_entry(p, &ftrace_commands, list) {
if (strcmp(p->name, command) == 0) {
ret = p->func(hash, func, command, next, enable);
goto out_unlock;
}
}
out_unlock:
mutex_unlock(&ftrace_cmd_mutex);
return ret;
}
static ssize_t
ftrace_regex_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos, int enable)
{
struct ftrace_iterator *iter;
struct trace_parser *parser;
ssize_t ret, read;
if (!cnt)
return 0;
mutex_lock(&ftrace_regex_lock);
ret = -ENODEV;
if (unlikely(ftrace_disabled))
goto out_unlock;
if (file->f_mode & FMODE_READ) {
struct seq_file *m = file->private_data;
iter = m->private;
} else
iter = file->private_data;
parser = &iter->parser;
read = trace_get_user(parser, ubuf, cnt, ppos);
if (read >= 0 && trace_parser_loaded(parser) &&
!trace_parser_cont(parser)) {
ret = ftrace_process_regex(iter->hash, parser->buffer,
parser->idx, enable);
trace_parser_clear(parser);
if (ret)
goto out_unlock;
}
ret = read;
out_unlock:
mutex_unlock(&ftrace_regex_lock);
return ret;
}
static ssize_t
ftrace_filter_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
}
static ssize_t
ftrace_notrace_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
}
static int
ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
int reset, int enable)
{
struct ftrace_hash **orig_hash;
struct ftrace_hash *hash;
int ret;
/* All global ops uses the global ops filters */
if (ops->flags & FTRACE_OPS_FL_GLOBAL)
ops = &global_ops;
if (unlikely(ftrace_disabled))
return -ENODEV;
if (enable)
orig_hash = &ops->filter_hash;
else
orig_hash = &ops->notrace_hash;
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
if (!hash)
return -ENOMEM;
mutex_lock(&ftrace_regex_lock);
if (reset)
ftrace_filter_reset(hash);
if (buf)
ftrace_match_records(hash, buf, len);
mutex_lock(&ftrace_lock);
ret = ftrace_hash_move(ops, enable, orig_hash, hash);
if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
&& ftrace_enabled)
ftrace_run_update_code(FTRACE_ENABLE_CALLS);
mutex_unlock(&ftrace_lock);
mutex_unlock(&ftrace_regex_lock);
free_ftrace_hash(hash);
return ret;
}
/**
* ftrace_set_filter - set a function to filter on in ftrace
* @ops - the ops to set the filter with
* @buf - the string that holds the function filter text.
* @len - the length of the string.
* @reset - non zero to reset all filters before applying this filter.
*
* Filters denote which functions should be enabled when tracing is enabled.
* If @buf is NULL and reset is set, all functions will be enabled for tracing.
*/
void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
int len, int reset)
{
ftrace_set_regex(ops, buf, len, reset, 1);
}
EXPORT_SYMBOL_GPL(ftrace_set_filter);
/**
* ftrace_set_notrace - set a function to not trace in ftrace
* @ops - the ops to set the notrace filter with
* @buf - the string that holds the function notrace text.
* @len - the length of the string.
* @reset - non zero to reset all filters before applying this filter.
*
* Notrace Filters denote which functions should not be enabled when tracing
* is enabled. If @buf is NULL and reset is set, all functions will be enabled
* for tracing.
*/
void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
int len, int reset)
{
ftrace_set_regex(ops, buf, len, reset, 0);
}
EXPORT_SYMBOL_GPL(ftrace_set_notrace);
/**
* ftrace_set_filter - set a function to filter on in ftrace
* @ops - the ops to set the filter with
* @buf - the string that holds the function filter text.
* @len - the length of the string.
* @reset - non zero to reset all filters before applying this filter.
*
* Filters denote which functions should be enabled when tracing is enabled.
* If @buf is NULL and reset is set, all functions will be enabled for tracing.
*/
void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
{
ftrace_set_regex(&global_ops, buf, len, reset, 1);
}
EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
/**
* ftrace_set_notrace - set a function to not trace in ftrace
* @ops - the ops to set the notrace filter with
* @buf - the string that holds the function notrace text.
* @len - the length of the string.
* @reset - non zero to reset all filters before applying this filter.
*
* Notrace Filters denote which functions should not be enabled when tracing
* is enabled. If @buf is NULL and reset is set, all functions will be enabled
* for tracing.
*/
void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
{
ftrace_set_regex(&global_ops, buf, len, reset, 0);
}
EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
/*
* command line interface to allow users to set filters on boot up.
*/
#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
static int __init set_ftrace_notrace(char *str)
{
strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
return 1;
}
__setup("ftrace_notrace=", set_ftrace_notrace);
static int __init set_ftrace_filter(char *str)
{
strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
return 1;
}
__setup("ftrace_filter=", set_ftrace_filter);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
static int __init set_graph_function(char *str)
{
strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
return 1;
}
__setup("ftrace_graph_filter=", set_graph_function);
static void __init set_ftrace_early_graph(char *buf)
{
int ret;
char *func;
while (buf) {
func = strsep(&buf, ",");
/* we allow only one expression at a time */
ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
func);
if (ret)
printk(KERN_DEBUG "ftrace: function %s not "
"traceable\n", func);
}
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
static void __init
set_ftrace_early_filter(struct ftrace_ops *ops, char *buf, int enable)
{
char *func;
while (buf) {
func = strsep(&buf, ",");
ftrace_set_regex(ops, func, strlen(func), 0, enable);
}
}
static void __init set_ftrace_early_filters(void)
{
if (ftrace_filter_buf[0])
set_ftrace_early_filter(&global_ops, ftrace_filter_buf, 1);
if (ftrace_notrace_buf[0])
set_ftrace_early_filter(&global_ops, ftrace_notrace_buf, 0);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (ftrace_graph_buf[0])
set_ftrace_early_graph(ftrace_graph_buf);
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
}
static int
ftrace_regex_release(struct inode *inode, struct file *file)
{
struct seq_file *m = (struct seq_file *)file->private_data;
struct ftrace_iterator *iter;
struct ftrace_hash **orig_hash;
struct trace_parser *parser;
int filter_hash;
int ret;
mutex_lock(&ftrace_regex_lock);
if (file->f_mode & FMODE_READ) {
iter = m->private;
seq_release(inode, file);
} else
iter = file->private_data;
parser = &iter->parser;
if (trace_parser_loaded(parser)) {
parser->buffer[parser->idx] = 0;
ftrace_match_records(iter->hash, parser->buffer, parser->idx);
}
trace_parser_put(parser);
if (file->f_mode & FMODE_WRITE) {
filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
if (filter_hash)
orig_hash = &iter->ops->filter_hash;
else
orig_hash = &iter->ops->notrace_hash;
mutex_lock(&ftrace_lock);
ret = ftrace_hash_move(iter->ops, filter_hash,
orig_hash, iter->hash);
if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
&& ftrace_enabled)
ftrace_run_update_code(FTRACE_ENABLE_CALLS);
mutex_unlock(&ftrace_lock);
}
free_ftrace_hash(iter->hash);
kfree(iter);
mutex_unlock(&ftrace_regex_lock);
return 0;
}
static const struct file_operations ftrace_avail_fops = {
.open = ftrace_avail_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static const struct file_operations ftrace_enabled_fops = {
.open = ftrace_enabled_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static const struct file_operations ftrace_filter_fops = {
.open = ftrace_filter_open,
.read = seq_read,
.write = ftrace_filter_write,
.llseek = ftrace_regex_lseek,
.release = ftrace_regex_release,
};
static const struct file_operations ftrace_notrace_fops = {
.open = ftrace_notrace_open,
.read = seq_read,
.write = ftrace_notrace_write,
.llseek = ftrace_regex_lseek,
.release = ftrace_regex_release,
};
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static DEFINE_MUTEX(graph_lock);
int ftrace_graph_count;
int ftrace_graph_filter_enabled;
unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
static void *
__g_next(struct seq_file *m, loff_t *pos)
{
if (*pos >= ftrace_graph_count)
return NULL;
return &ftrace_graph_funcs[*pos];
}
static void *
g_next(struct seq_file *m, void *v, loff_t *pos)
{
(*pos)++;
return __g_next(m, pos);
}
static void *g_start(struct seq_file *m, loff_t *pos)
{
mutex_lock(&graph_lock);
/* Nothing, tell g_show to print all functions are enabled */
if (!ftrace_graph_filter_enabled && !*pos)
return (void *)1;
return __g_next(m, pos);
}
static void g_stop(struct seq_file *m, void *p)
{
mutex_unlock(&graph_lock);
}
static int g_show(struct seq_file *m, void *v)
{
unsigned long *ptr = v;
if (!ptr)
return 0;
if (ptr == (unsigned long *)1) {
seq_printf(m, "#### all functions enabled ####\n");
return 0;
}
seq_printf(m, "%ps\n", (void *)*ptr);
return 0;
}
static const struct seq_operations ftrace_graph_seq_ops = {
.start = g_start,
.next = g_next,
.stop = g_stop,
.show = g_show,
};
static int
ftrace_graph_open(struct inode *inode, struct file *file)
{
int ret = 0;
if (unlikely(ftrace_disabled))
return -ENODEV;
mutex_lock(&graph_lock);
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC)) {
ftrace_graph_filter_enabled = 0;
ftrace_graph_count = 0;
memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
}
mutex_unlock(&graph_lock);
if (file->f_mode & FMODE_READ)
ret = seq_open(file, &ftrace_graph_seq_ops);
return ret;
}
static int
ftrace_graph_release(struct inode *inode, struct file *file)
{
if (file->f_mode & FMODE_READ)
seq_release(inode, file);
return 0;
}
static int
ftrace_set_func(unsigned long *array, int *idx, char *buffer)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
int search_len;
int fail = 1;
int type, not;
char *search;
bool exists;
int i;
/* decode regex */
type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
return -EBUSY;
search_len = strlen(search);
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled)) {
mutex_unlock(&ftrace_lock);
return -ENODEV;
}
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_FREE)
continue;
if (ftrace_match_record(rec, NULL, search, search_len, type)) {
/* if it is in the array */
exists = false;
for (i = 0; i < *idx; i++) {
if (array[i] == rec->ip) {
exists = true;
break;
}
}
if (!not) {
fail = 0;
if (!exists) {
array[(*idx)++] = rec->ip;
if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
goto out;
}
} else {
if (exists) {
array[i] = array[--(*idx)];
array[*idx] = 0;
fail = 0;
}
}
}
} while_for_each_ftrace_rec();
out:
mutex_unlock(&ftrace_lock);
if (fail)
return -EINVAL;
ftrace_graph_filter_enabled = 1;
return 0;
}
static ssize_t
ftrace_graph_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_parser parser;
ssize_t read, ret;
if (!cnt)
return 0;
mutex_lock(&graph_lock);
if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
ret = -ENOMEM;
goto out_unlock;
}
read = trace_get_user(&parser, ubuf, cnt, ppos);
if (read >= 0 && trace_parser_loaded((&parser))) {
parser.buffer[parser.idx] = 0;
/* we allow only one expression at a time */
ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
parser.buffer);
if (ret)
goto out_free;
}
ret = read;
out_free:
trace_parser_put(&parser);
out_unlock:
mutex_unlock(&graph_lock);
return ret;
}
static const struct file_operations ftrace_graph_fops = {
.open = ftrace_graph_open,
.read = seq_read,
.write = ftrace_graph_write,
.release = ftrace_graph_release,
.llseek = seq_lseek,
};
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
{
trace_create_file("available_filter_functions", 0444,
d_tracer, NULL, &ftrace_avail_fops);
trace_create_file("enabled_functions", 0444,
d_tracer, NULL, &ftrace_enabled_fops);
trace_create_file("set_ftrace_filter", 0644, d_tracer,
NULL, &ftrace_filter_fops);
trace_create_file("set_ftrace_notrace", 0644, d_tracer,
NULL, &ftrace_notrace_fops);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
trace_create_file("set_graph_function", 0444, d_tracer,
NULL,
&ftrace_graph_fops);
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
return 0;
}
static int ftrace_process_locs(struct module *mod,
unsigned long *start,
unsigned long *end)
{
unsigned long *p;
unsigned long addr;
unsigned long flags = 0; /* Shut up gcc */
mutex_lock(&ftrace_lock);
p = start;
while (p < end) {
addr = ftrace_call_adjust(*p++);
/*
* Some architecture linkers will pad between
* the different mcount_loc sections of different
* object files to satisfy alignments.
* Skip any NULL pointers.
*/
if (!addr)
continue;
ftrace_record_ip(addr);
}
/*
* We only need to disable interrupts on start up
* because we are modifying code that an interrupt
* may execute, and the modification is not atomic.
* But for modules, nothing runs the code we modify
* until we are finished with it, and there's no
* reason to cause large interrupt latencies while we do it.
*/
if (!mod)
local_irq_save(flags);
ftrace_update_code(mod);
if (!mod)
local_irq_restore(flags);
mutex_unlock(&ftrace_lock);
return 0;
}
#ifdef CONFIG_MODULES
void ftrace_release_mod(struct module *mod)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
mutex_lock(&ftrace_lock);
if (ftrace_disabled)
goto out_unlock;
do_for_each_ftrace_rec(pg, rec) {
if (within_module_core(rec->ip, mod)) {
/*
* rec->ip is changed in ftrace_free_rec()
* It should not between s and e if record was freed.
*/
FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
ftrace_free_rec(rec);
}
} while_for_each_ftrace_rec();
out_unlock:
mutex_unlock(&ftrace_lock);
}
static void ftrace_init_module(struct module *mod,
unsigned long *start, unsigned long *end)
{
if (ftrace_disabled || start == end)
return;
ftrace_process_locs(mod, start, end);
}
static int ftrace_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct module *mod = data;
switch (val) {
case MODULE_STATE_COMING:
ftrace_init_module(mod, mod->ftrace_callsites,
mod->ftrace_callsites +
mod->num_ftrace_callsites);
break;
case MODULE_STATE_GOING:
ftrace_release_mod(mod);
break;
}
return 0;
}
#else
static int ftrace_module_notify(struct notifier_block *self,
unsigned long val, void *data)
{
return 0;
}
#endif /* CONFIG_MODULES */
struct notifier_block ftrace_module_nb = {
.notifier_call = ftrace_module_notify,
.priority = 0,
};
extern unsigned long __start_mcount_loc[];
extern unsigned long __stop_mcount_loc[];
void __init ftrace_init(void)
{
unsigned long count, addr, flags;
int ret;
/* Keep the ftrace pointer to the stub */
addr = (unsigned long)ftrace_stub;
local_irq_save(flags);
ftrace_dyn_arch_init(&addr);
local_irq_restore(flags);
/* ftrace_dyn_arch_init places the return code in addr */
if (addr)
goto failed;
count = __stop_mcount_loc - __start_mcount_loc;
ret = ftrace_dyn_table_alloc(count);
if (ret)
goto failed;
last_ftrace_enabled = ftrace_enabled = 1;
ret = ftrace_process_locs(NULL,
__start_mcount_loc,
__stop_mcount_loc);
ret = register_module_notifier(&ftrace_module_nb);
if (ret)
pr_warning("Failed to register trace ftrace module notifier\n");
set_ftrace_early_filters();
return;
failed:
ftrace_disabled = 1;
}
#else
static struct ftrace_ops global_ops = {
.func = ftrace_stub,
};
static int __init ftrace_nodyn_init(void)
{
ftrace_enabled = 1;
return 0;
}
device_initcall(ftrace_nodyn_init);
static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
static inline void ftrace_startup_enable(int command) { }
/* Keep as macros so we do not need to define the commands */
# define ftrace_startup(ops, command) \
({ \
(ops)->flags |= FTRACE_OPS_FL_ENABLED; \
0; \
})
# define ftrace_shutdown(ops, command) do { } while (0)
# define ftrace_startup_sysctl() do { } while (0)
# define ftrace_shutdown_sysctl() do { } while (0)
static inline int
ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
{
return 1;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
static void
ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
{
struct ftrace_ops *op;
if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
return;
trace_recursion_set(TRACE_INTERNAL_BIT);
/*
* Some of the ops may be dynamically allocated,
* they must be freed after a synchronize_sched().
*/
preempt_disable_notrace();
op = rcu_dereference_raw(ftrace_ops_list);
while (op != &ftrace_list_end) {
if (ftrace_ops_test(op, ip))
op->func(ip, parent_ip);
op = rcu_dereference_raw(op->next);
};
preempt_enable_notrace();
trace_recursion_clear(TRACE_INTERNAL_BIT);
}
static void clear_ftrace_swapper(void)
{
struct task_struct *p;
int cpu;
get_online_cpus();
for_each_online_cpu(cpu) {
p = idle_task(cpu);
clear_tsk_trace_trace(p);
}
put_online_cpus();
}
static void set_ftrace_swapper(void)
{
struct task_struct *p;
int cpu;
get_online_cpus();
for_each_online_cpu(cpu) {
p = idle_task(cpu);
set_tsk_trace_trace(p);
}
put_online_cpus();
}
static void clear_ftrace_pid(struct pid *pid)
{
struct task_struct *p;
rcu_read_lock();
do_each_pid_task(pid, PIDTYPE_PID, p) {
clear_tsk_trace_trace(p);
} while_each_pid_task(pid, PIDTYPE_PID, p);
rcu_read_unlock();
put_pid(pid);
}
static void set_ftrace_pid(struct pid *pid)
{
struct task_struct *p;
rcu_read_lock();
do_each_pid_task(pid, PIDTYPE_PID, p) {
set_tsk_trace_trace(p);
} while_each_pid_task(pid, PIDTYPE_PID, p);
rcu_read_unlock();
}
static void clear_ftrace_pid_task(struct pid *pid)
{
if (pid == ftrace_swapper_pid)
clear_ftrace_swapper();
else
clear_ftrace_pid(pid);
}
static void set_ftrace_pid_task(struct pid *pid)
{
if (pid == ftrace_swapper_pid)
set_ftrace_swapper();
else
set_ftrace_pid(pid);
}
static int ftrace_pid_add(int p)
{
struct pid *pid;
struct ftrace_pid *fpid;
int ret = -EINVAL;
mutex_lock(&ftrace_lock);
if (!p)
pid = ftrace_swapper_pid;
else
pid = find_get_pid(p);
if (!pid)
goto out;
ret = 0;
list_for_each_entry(fpid, &ftrace_pids, list)
if (fpid->pid == pid)
goto out_put;
ret = -ENOMEM;
fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
if (!fpid)
goto out_put;
list_add(&fpid->list, &ftrace_pids);
fpid->pid = pid;
set_ftrace_pid_task(pid);
ftrace_update_pid_func();
ftrace_startup_enable(0);
mutex_unlock(&ftrace_lock);
return 0;
out_put:
if (pid != ftrace_swapper_pid)
put_pid(pid);
out:
mutex_unlock(&ftrace_lock);
return ret;
}
static void ftrace_pid_reset(void)
{
struct ftrace_pid *fpid, *safe;
mutex_lock(&ftrace_lock);
list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
struct pid *pid = fpid->pid;
clear_ftrace_pid_task(pid);
list_del(&fpid->list);
kfree(fpid);
}
ftrace_update_pid_func();
ftrace_startup_enable(0);
mutex_unlock(&ftrace_lock);
}
static void *fpid_start(struct seq_file *m, loff_t *pos)
{
mutex_lock(&ftrace_lock);
if (list_empty(&ftrace_pids) && (!*pos))
return (void *) 1;
return seq_list_start(&ftrace_pids, *pos);
}
static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
{
if (v == (void *)1)
return NULL;
return seq_list_next(v, &ftrace_pids, pos);
}
static void fpid_stop(struct seq_file *m, void *p)
{
mutex_unlock(&ftrace_lock);
}
static int fpid_show(struct seq_file *m, void *v)
{
const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
if (v == (void *)1) {
seq_printf(m, "no pid\n");
return 0;
}
if (fpid->pid == ftrace_swapper_pid)
seq_printf(m, "swapper tasks\n");
else
seq_printf(m, "%u\n", pid_vnr(fpid->pid));
return 0;
}
static const struct seq_operations ftrace_pid_sops = {
.start = fpid_start,
.next = fpid_next,
.stop = fpid_stop,
.show = fpid_show,
};
static int
ftrace_pid_open(struct inode *inode, struct file *file)
{
int ret = 0;
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC))
ftrace_pid_reset();
if (file->f_mode & FMODE_READ)
ret = seq_open(file, &ftrace_pid_sops);
return ret;
}
static ssize_t
ftrace_pid_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[64], *tmp;
long val;
int ret;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
/*
* Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
* to clean the filter quietly.
*/
tmp = strstrip(buf);
if (strlen(tmp) == 0)
return 1;
ret = strict_strtol(tmp, 10, &val);
if (ret < 0)
return ret;
ret = ftrace_pid_add(val);
return ret ? ret : cnt;
}
static int
ftrace_pid_release(struct inode *inode, struct file *file)
{
if (file->f_mode & FMODE_READ)
seq_release(inode, file);
return 0;
}
static const struct file_operations ftrace_pid_fops = {
.open = ftrace_pid_open,
.write = ftrace_pid_write,
.read = seq_read,
.llseek = seq_lseek,
.release = ftrace_pid_release,
};
static __init int ftrace_init_debugfs(void)
{
struct dentry *d_tracer;
d_tracer = tracing_init_dentry();
if (!d_tracer)
return 0;
ftrace_init_dyn_debugfs(d_tracer);
trace_create_file("set_ftrace_pid", 0644, d_tracer,
NULL, &ftrace_pid_fops);
ftrace_profile_debugfs(d_tracer);
return 0;
}
fs_initcall(ftrace_init_debugfs);
/**
* ftrace_kill - kill ftrace
*
* This function should be used by panic code. It stops ftrace
* but in a not so nice way. If you need to simply kill ftrace
* from a non-atomic section, use ftrace_kill.
*/
void ftrace_kill(void)
{
ftrace_disabled = 1;
ftrace_enabled = 0;
clear_ftrace_function();
}
/**
* Test if ftrace is dead or not.
*/
int ftrace_is_dead(void)
{
return ftrace_disabled;
}
/**
* register_ftrace_function - register a function for profiling
* @ops - ops structure that holds the function for profiling.
*
* Register a function to be called by all functions in the
* kernel.
*
* Note: @ops->func and all the functions it calls must be labeled
* with "notrace", otherwise it will go into a
* recursive loop.
*/
int register_ftrace_function(struct ftrace_ops *ops)
{
int ret = -1;
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled))
goto out_unlock;
ret = __register_ftrace_function(ops);
if (!ret)
ret = ftrace_startup(ops, 0);
out_unlock:
mutex_unlock(&ftrace_lock);
return ret;
}
EXPORT_SYMBOL_GPL(register_ftrace_function);
/**
* unregister_ftrace_function - unregister a function for profiling.
* @ops - ops structure that holds the function to unregister
*
* Unregister a function that was added to be called by ftrace profiling.
*/
int unregister_ftrace_function(struct ftrace_ops *ops)
{
int ret;
mutex_lock(&ftrace_lock);
ret = __unregister_ftrace_function(ops);
if (!ret)
ftrace_shutdown(ops, 0);
mutex_unlock(&ftrace_lock);
return ret;
}
EXPORT_SYMBOL_GPL(unregister_ftrace_function);
int
ftrace_enable_sysctl(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
int ret = -ENODEV;
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled))
goto out;
ret = proc_dointvec(table, write, buffer, lenp, ppos);
if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
goto out;
last_ftrace_enabled = !!ftrace_enabled;
if (ftrace_enabled) {
ftrace_startup_sysctl();
/* we are starting ftrace again */
if (ftrace_ops_list != &ftrace_list_end) {
if (ftrace_ops_list->next == &ftrace_list_end)
ftrace_trace_function = ftrace_ops_list->func;
else
ftrace_trace_function = ftrace_ops_list_func;
}
} else {
/* stopping ftrace calls (just send to ftrace_stub) */
ftrace_trace_function = ftrace_stub;
ftrace_shutdown_sysctl();
}
out:
mutex_unlock(&ftrace_lock);
return ret;
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static int ftrace_graph_active;
static struct notifier_block ftrace_suspend_notifier;
int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
{
return 0;
}
/* The callbacks that hook a function */
trace_func_graph_ret_t ftrace_graph_return =
(trace_func_graph_ret_t)ftrace_stub;
trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
{
int i;
int ret = 0;
unsigned long flags;
int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
struct task_struct *g, *t;
for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
* sizeof(struct ftrace_ret_stack),
GFP_KERNEL);
if (!ret_stack_list[i]) {
start = 0;
end = i;
ret = -ENOMEM;
goto free;
}
}
read_lock_irqsave(&tasklist_lock, flags);
do_each_thread(g, t) {
if (start == end) {
ret = -EAGAIN;
goto unlock;
}
if (t->ret_stack == NULL) {
atomic_set(&t->tracing_graph_pause, 0);
atomic_set(&t->trace_overrun, 0);
t->curr_ret_stack = -1;
/* Make sure the tasks see the -1 first: */
smp_wmb();
t->ret_stack = ret_stack_list[start++];
}
} while_each_thread(g, t);
unlock:
read_unlock_irqrestore(&tasklist_lock, flags);
free:
for (i = start; i < end; i++)
kfree(ret_stack_list[i]);
return ret;
}
static void
ftrace_graph_probe_sched_switch(void *ignore,
struct task_struct *prev, struct task_struct *next)
{
unsigned long long timestamp;
int index;
/*
* Does the user want to count the time a function was asleep.
* If so, do not update the time stamps.
*/
if (trace_flags & TRACE_ITER_SLEEP_TIME)
return;
timestamp = trace_clock_local();
prev->ftrace_timestamp = timestamp;
/* only process tasks that we timestamped */
if (!next->ftrace_timestamp)
return;
/*
* Update all the counters in next to make up for the
* time next was sleeping.
*/
timestamp -= next->ftrace_timestamp;
for (index = next->curr_ret_stack; index >= 0; index--)
next->ret_stack[index].calltime += timestamp;
}
/* Allocate a return stack for each task */
static int start_graph_tracing(void)
{
struct ftrace_ret_stack **ret_stack_list;
int ret, cpu;
ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
sizeof(struct ftrace_ret_stack *),
GFP_KERNEL);
if (!ret_stack_list)
return -ENOMEM;
/* The cpu_boot init_task->ret_stack will never be freed */
for_each_online_cpu(cpu) {
if (!idle_task(cpu)->ret_stack)
ftrace_graph_init_idle_task(idle_task(cpu), cpu);
}
do {
ret = alloc_retstack_tasklist(ret_stack_list);
} while (ret == -EAGAIN);
if (!ret) {
ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
if (ret)
pr_info("ftrace_graph: Couldn't activate tracepoint"
" probe to kernel_sched_switch\n");
}
kfree(ret_stack_list);
return ret;
}
/*
* Hibernation protection.
* The state of the current task is too much unstable during
* suspend/restore to disk. We want to protect against that.
*/
static int
ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
void *unused)
{
switch (state) {
case PM_HIBERNATION_PREPARE:
pause_graph_tracing();
break;
case PM_POST_HIBERNATION:
unpause_graph_tracing();
break;
}
return NOTIFY_DONE;
}
int register_ftrace_graph(trace_func_graph_ret_t retfunc,
trace_func_graph_ent_t entryfunc)
{
int ret = 0;
mutex_lock(&ftrace_lock);
/* we currently allow only one tracer registered at a time */
if (ftrace_graph_active) {
ret = -EBUSY;
goto out;
}
ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
register_pm_notifier(&ftrace_suspend_notifier);
ftrace_graph_active++;
ret = start_graph_tracing();
if (ret) {
ftrace_graph_active--;
goto out;
}
ftrace_graph_return = retfunc;
ftrace_graph_entry = entryfunc;
ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
out:
mutex_unlock(&ftrace_lock);
return ret;
}
void unregister_ftrace_graph(void)
{
mutex_lock(&ftrace_lock);
if (unlikely(!ftrace_graph_active))
goto out;
ftrace_graph_active--;
ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
ftrace_graph_entry = ftrace_graph_entry_stub;
ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
unregister_pm_notifier(&ftrace_suspend_notifier);
unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
out:
mutex_unlock(&ftrace_lock);
}
static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
static void
graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
{
atomic_set(&t->tracing_graph_pause, 0);
atomic_set(&t->trace_overrun, 0);
t->ftrace_timestamp = 0;
/* make curr_ret_stack visible before we add the ret_stack */
smp_wmb();
t->ret_stack = ret_stack;
}
/*
* Allocate a return stack for the idle task. May be the first
* time through, or it may be done by CPU hotplug online.
*/
void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
{
t->curr_ret_stack = -1;
/*
* The idle task has no parent, it either has its own
* stack or no stack at all.
*/
if (t->ret_stack)
WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
if (ftrace_graph_active) {
struct ftrace_ret_stack *ret_stack;
ret_stack = per_cpu(idle_ret_stack, cpu);
if (!ret_stack) {
ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
* sizeof(struct ftrace_ret_stack),
GFP_KERNEL);
if (!ret_stack)
return;
per_cpu(idle_ret_stack, cpu) = ret_stack;
}
graph_init_task(t, ret_stack);
}
}
/* Allocate a return stack for newly created task */
void ftrace_graph_init_task(struct task_struct *t)
{
/* Make sure we do not use the parent ret_stack */
t->ret_stack = NULL;
t->curr_ret_stack = -1;
if (ftrace_graph_active) {
struct ftrace_ret_stack *ret_stack;
ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
* sizeof(struct ftrace_ret_stack),
GFP_KERNEL);
if (!ret_stack)
return;
graph_init_task(t, ret_stack);
}
}
void ftrace_graph_exit_task(struct task_struct *t)
{
struct ftrace_ret_stack *ret_stack = t->ret_stack;
t->ret_stack = NULL;
/* NULL must become visible to IRQs before we free it: */
barrier();
kfree(ret_stack);
}
void ftrace_graph_stop(void)
{
ftrace_stop();
}
#endif
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