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linux-sg2042/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/kprobes.h>
#include <linux/ftrace.h>
#include <linux/sysctl.h>
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/hash.h>
#include <trace/events/sched.h>
#include <asm/ftrace.h>
#include <asm/setup.h>
#include "trace_output.h"
#include "trace_stat.h"
#define FTRACE_WARN_ON(cond) \
do { \
if (WARN_ON(cond)) \
ftrace_kill(); \
} while (0)
#define FTRACE_WARN_ON_ONCE(cond) \
do { \
if (WARN_ON_ONCE(cond)) \
ftrace_kill(); \
} while (0)
/* hash bits for specific function selection */
#define FTRACE_HASH_BITS 7
#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
/* 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_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
#endif
static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
{
struct ftrace_ops *op = ftrace_list;
/* in case someone actually ports this to alpha! */
read_barrier_depends();
while (op != &ftrace_list_end) {
/* silly alpha */
read_barrier_depends();
op->func(ip, parent_ip);
op = op->next;
};
}
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_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 int __register_ftrace_function(struct ftrace_ops *ops)
{
ops->next = ftrace_list;
/*
* We are entering ops into the ftrace_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 ftrace_list.
*/
smp_wmb();
ftrace_list = ops;
if (ftrace_enabled) {
ftrace_func_t func;
if (ops->next == &ftrace_list_end)
func = ops->func;
else
func = ftrace_list_func;
if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
/*
* For one func, simply call it directly.
* For more than one func, call the chain.
*/
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
__ftrace_trace_function = func;
ftrace_trace_function = ftrace_test_stop_func;
#endif
}
return 0;
}
static int __unregister_ftrace_function(struct ftrace_ops *ops)
{
struct ftrace_ops **p;
/*
* If we are removing the last function, then simply point
* to the ftrace_stub.
*/
if (ftrace_list == ops && ops->next == &ftrace_list_end) {
ftrace_trace_function = ftrace_stub;
ftrace_list = &ftrace_list_end;
return 0;
}
for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
if (*p == ops)
break;
if (*p != ops)
return -1;
*p = (*p)->next;
if (ftrace_enabled) {
/* If we only have one func left, then call that directly */
if (ftrace_list->next == &ftrace_list_end) {
ftrace_func_t func = ftrace_list->func;
if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
__ftrace_trace_function = func;
#endif
}
}
return 0;
}
static void ftrace_update_pid_func(void)
{
ftrace_func_t func;
if (ftrace_trace_function == ftrace_stub)
return;
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
func = ftrace_trace_function;
#else
func = __ftrace_trace_function;
#endif
if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
} else {
if (func == ftrace_pid_func)
func = ftrace_pid_function;
}
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
__ftrace_trace_function = func;
#endif
}
#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;
#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\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];
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static DEFINE_MUTEX(mutex);
static struct trace_seq s;
unsigned long long avg;
#endif
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);
mutex_lock(&mutex);
trace_seq_init(&s);
trace_print_graph_duration(rec->time, &s);
trace_seq_puts(&s, " ");
trace_print_graph_duration(avg, &s);
trace_print_seq(m, &s);
mutex_unlock(&mutex);
#endif
seq_putc(m, '\n');
return 0;
}
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;
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;
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;
char buf[64]; /* big enough to hold a number */
int ret;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
ret = strict_strtoul(buf, 10, &val);
if (ret < 0)
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,
};
/* 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_ENABLE_MCOUNT = (1 << 3),
FTRACE_DISABLE_MCOUNT = (1 << 4),
FTRACE_START_FUNC_RET = (1 << 5),
FTRACE_STOP_FUNC_RET = (1 << 6),
};
static int ftrace_filtered;
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;
/*
* 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() \
} \
}
#ifdef CONFIG_KPROBES
static int frozen_record_count;
static inline void freeze_record(struct dyn_ftrace *rec)
{
if (!(rec->flags & FTRACE_FL_FROZEN)) {
rec->flags |= FTRACE_FL_FROZEN;
frozen_record_count++;
}
}
static inline void unfreeze_record(struct dyn_ftrace *rec)
{
if (rec->flags & FTRACE_FL_FROZEN) {
rec->flags &= ~FTRACE_FL_FROZEN;
frozen_record_count--;
}
}
static inline int record_frozen(struct dyn_ftrace *rec)
{
return rec->flags & FTRACE_FL_FROZEN;
}
#else
# define freeze_record(rec) ({ 0; })
# define unfreeze_record(rec) ({ 0; })
# define record_frozen(rec) ({ 0; })
#endif /* CONFIG_KPROBES */
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);
}
}
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 this record is not to be traced or we want to disable it,
* then disable it.
*
* If we want to enable it and filtering is off, then enable it.
*
* If we want to enable it and filtering is on, enable it only if
* it's filtered
*/
if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
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;
do_for_each_ftrace_rec(pg, rec) {
/*
* Skip over free records, records that have
* failed and not converted.
*/
if (rec->flags & FTRACE_FL_FREE ||
rec->flags & FTRACE_FL_FAILED ||
!(rec->flags & FTRACE_FL_CONVERTED))
continue;
/* ignore updates to this record's mcount site */
if (get_kprobe((void *)rec->ip)) {
freeze_record(rec);
continue;
} else {
unfreeze_record(rec);
}
failed = __ftrace_replace_code(rec, enable);
if (failed) {
rec->flags |= FTRACE_FL_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;
ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
if (ret) {
ftrace_bug(ret, ip);
rec->flags |= FTRACE_FL_FAILED;
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;
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();
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 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 void ftrace_startup(int command)
{
if (unlikely(ftrace_disabled))
return;
ftrace_start_up++;
command |= FTRACE_ENABLE_CALLS;
ftrace_startup_enable(command);
}
static void ftrace_shutdown(int command)
{
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 (!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)
{
int command = FTRACE_ENABLE_MCOUNT;
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)
command |= FTRACE_ENABLE_CALLS;
ftrace_run_update_code(command);
}
static void ftrace_shutdown_sysctl(void)
{
int command = FTRACE_DISABLE_MCOUNT;
if (unlikely(ftrace_disabled))
return;
/* ftrace_start_up is true if ftrace is running */
if (ftrace_start_up)
command |= FTRACE_DISABLE_CALLS;
ftrace_run_update_code(command);
}
static cycle_t ftrace_update_time;
static unsigned long ftrace_update_cnt;
unsigned long ftrace_update_tot_cnt;
static int ftrace_update_code(struct module *mod)
{
struct dyn_ftrace *p;
cycle_t start, stop;
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 = 0L;
/*
* Do the initial record convertion from mcount jump
* to the NOP instructions.
*/
if (!ftrace_code_disable(mod, p)) {
ftrace_free_rec(p);
continue;
}
p->flags |= FTRACE_FL_CONVERTED;
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) {
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_FAILURES = (1 << 2),
FTRACE_ITER_PRINTALL = (1 << 3),
FTRACE_ITER_HASH = (1 << 4),
};
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
struct ftrace_iterator {
struct ftrace_page *pg;
int hidx;
int idx;
unsigned flags;
struct trace_parser parser;
};
static void *
t_hash_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
struct hlist_node *hnd = v;
struct hlist_head *hhd;
WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
(*pos)++;
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;
}
}
return hnd;
}
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->flags & FTRACE_ITER_HASH))
*pos = 0;
iter->flags |= FTRACE_ITER_HASH;
iter->hidx = 0;
for (l = 0; l <= *pos; ) {
p = t_hash_next(m, p, &l);
if (!p)
break;
}
return p;
}
static int t_hash_show(struct seq_file *m, void *v)
{
struct ftrace_func_probe *rec;
struct hlist_node *hnd = v;
rec = hlist_entry(hnd, struct ftrace_func_probe, node);
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 dyn_ftrace *rec = NULL;
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_next(m, v, pos);
(*pos)++;
if (iter->flags & FTRACE_ITER_PRINTALL)
return NULL;
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_FAILURES) &&
(rec->flags & FTRACE_FL_FAILED)) ||
((iter->flags & FTRACE_ITER_FAILURES) &&
!(rec->flags & FTRACE_FL_FAILED)) ||
((iter->flags & FTRACE_ITER_FILTER) &&
!(rec->flags & FTRACE_FL_FILTER)) ||
((iter->flags & FTRACE_ITER_NOTRACE) &&
!(rec->flags & FTRACE_FL_NOTRACE))) {
rec = NULL;
goto retry;
}
}
return rec;
}
static void *t_start(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
void *p = NULL;
loff_t l;
mutex_lock(&ftrace_lock);
/*
* 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 && !ftrace_filtered) {
if (*pos > 0)
return t_hash_start(m, pos);
iter->flags |= FTRACE_ITER_PRINTALL;
return iter;
}
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_start(m, pos);
iter->pg = ftrace_pages_start;
iter->idx = 0;
for (l = 0; l <= *pos; ) {
p = t_next(m, p, &l);
if (!p)
break;
}
if (!p && iter->flags & FTRACE_ITER_FILTER)
return t_hash_start(m, pos);
return p;
}
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 = v;
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_show(m, v);
if (iter->flags & FTRACE_ITER_PRINTALL) {
seq_printf(m, "#### all functions enabled ####\n");
return 0;
}
if (!rec)
return 0;
seq_printf(m, "%ps\n", (void *)rec->ip);
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_failures_open(struct inode *inode, struct file *file)
{
int ret;
struct seq_file *m;
struct ftrace_iterator *iter;
ret = ftrace_avail_open(inode, file);
if (!ret) {
m = (struct seq_file *)file->private_data;
iter = (struct ftrace_iterator *)m->private;
iter->flags = FTRACE_ITER_FAILURES;
}
return ret;
}
static void ftrace_filter_reset(int enable)
{
struct ftrace_page *pg;
struct dyn_ftrace *rec;
unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
mutex_lock(&ftrace_lock);
if (enable)
ftrace_filtered = 0;
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_FAILED)
continue;
rec->flags &= ~type;
} while_for_each_ftrace_rec();
mutex_unlock(&ftrace_lock);
}
static int
ftrace_regex_open(struct inode *inode, struct file *file, int enable)
{
struct ftrace_iterator *iter;
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;
}
mutex_lock(&ftrace_regex_lock);
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC))
ftrace_filter_reset(enable);
if (file->f_mode & FMODE_READ) {
iter->pg = ftrace_pages_start;
iter->flags = enable ? FTRACE_ITER_FILTER :
FTRACE_ITER_NOTRACE;
ret = seq_open(file, &show_ftrace_seq_ops);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = iter;
} else {
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(inode, file, 1);
}
static int
ftrace_notrace_open(struct inode *inode, struct file *file)
{
return ftrace_regex_open(inode, file, 0);
}
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;
char *ptr;
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:
ptr = strstr(str, regex);
if (ptr && (ptr[len] == 0))
matched = 1;
break;
}
return matched;
}
static int
ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
{
char str[KSYM_SYMBOL_LEN];
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
return ftrace_match(str, regex, len, type);
}
static int ftrace_match_records(char *buff, int len, int enable)
{
unsigned int search_len;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
unsigned long flag;
char *search;
int type;
int not;
int found = 0;
flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
type = filter_parse_regex(buff, len, &search, &not);
search_len = strlen(search);
mutex_lock(&ftrace_lock);
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_FAILED)
continue;
if (ftrace_match_record(rec, search, search_len, type)) {
if (not)
rec->flags &= ~flag;
else
rec->flags |= flag;
found = 1;
}
/*
* Only enable filtering if we have a function that
* is filtered on.
*/
if (enable && (rec->flags & FTRACE_FL_FILTER))
ftrace_filtered = 1;
} while_for_each_ftrace_rec();
mutex_unlock(&ftrace_lock);
return found;
}
static int
ftrace_match_module_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 (!modname || strcmp(modname, mod))
return 0;
/* blank search means to match all funcs in the mod */
if (len)
return ftrace_match(str, regex, len, type);
else
return 1;
}
static int ftrace_match_module_records(char *buff, char *mod, int enable)
{
unsigned search_len = 0;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
int type = MATCH_FULL;
char *search = buff;
unsigned long flag;
int not = 0;
int found = 0;
flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
/* 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;
}
if (strlen(buff)) {
type = filter_parse_regex(buff, strlen(buff), &search, &not);
search_len = strlen(search);
}
mutex_lock(&ftrace_lock);
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_FAILED)
continue;
if (ftrace_match_module_record(rec, mod,
search, search_len, type)) {
if (not)
rec->flags &= ~flag;
else
rec->flags |= flag;
found = 1;
}
if (enable && (rec->flags & FTRACE_FL_FILTER))
ftrace_filtered = 1;
} while_for_each_ftrace_rec();
mutex_unlock(&ftrace_lock);
return found;
}
/*
* We register the module command as a template to show others how
* to register the a command as well.
*/
static int
ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
{
char *mod;
/*
* 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 -EINVAL;
mod = strsep(&param, ":");
if (!strlen(mod))
return -EINVAL;
if (ftrace_match_module_records(func, mod, enable))
return 0;
return -EINVAL;
}
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;
int resched;
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.
*/
resched = ftrace_preempt_disable();
hlist_for_each_entry_rcu(entry, n, hhd, node) {
if (entry->ip == ip)
entry->ops->func(ip, parent_ip, &entry->data);
}
ftrace_preempt_enable(resched);
}
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 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;
__register_ftrace_function(&trace_probe_ops);
ftrace_startup(0);
ftrace_probe_registered = 1;
}
static void __disable_ftrace_function_probe(void)
{
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 */
__unregister_ftrace_function(&trace_probe_ops);
ftrace_shutdown(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);
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_FAILED)
continue;
if (!ftrace_match_record(rec, 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(char *buff, int len, int enable)
{
char *func, *command, *next = buff;
struct ftrace_func_command *p;
int ret = -EINVAL;
func = strsep(&next, ":");
if (!next) {
if (ftrace_match_records(func, len, enable))
return 0;
return ret;
}
/* 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(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);
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(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 void
ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
{
if (unlikely(ftrace_disabled))
return;
mutex_lock(&ftrace_regex_lock);
if (reset)
ftrace_filter_reset(enable);
if (buf)
ftrace_match_records(buf, len, enable);
mutex_unlock(&ftrace_regex_lock);
}
/**
* ftrace_set_filter - set a function to filter on in ftrace
* @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(unsigned char *buf, int len, int reset)
{
ftrace_set_regex(buf, len, reset, 1);
}
/**
* ftrace_set_notrace - set a function to not trace in ftrace
* @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(unsigned char *buf, int len, int reset)
{
ftrace_set_regex(buf, len, reset, 0);
}
/*
* 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 __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(char *buf, int enable)
{
char *func;
while (buf) {
func = strsep(&buf, ",");
ftrace_set_regex(func, strlen(func), 0, enable);
}
}
static void __init set_ftrace_early_filters(void)
{
if (ftrace_filter_buf[0])
set_ftrace_early_filter(ftrace_filter_buf, 1);
if (ftrace_notrace_buf[0])
set_ftrace_early_filter(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, int enable)
{
struct seq_file *m = (struct seq_file *)file->private_data;
struct ftrace_iterator *iter;
struct trace_parser *parser;
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(parser->buffer, parser->idx, enable);
}
mutex_lock(&ftrace_lock);
if (ftrace_start_up && ftrace_enabled)
ftrace_run_update_code(FTRACE_ENABLE_CALLS);
mutex_unlock(&ftrace_lock);
trace_parser_put(parser);
kfree(iter);
mutex_unlock(&ftrace_regex_lock);
return 0;
}
static int
ftrace_filter_release(struct inode *inode, struct file *file)
{
return ftrace_regex_release(inode, file, 1);
}
static int
ftrace_notrace_release(struct inode *inode, struct file *file)
{
return ftrace_regex_release(inode, file, 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_failures_fops = {
.open = ftrace_failures_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_filter_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_notrace_release,
};
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static DEFINE_MUTEX(graph_lock);
int ftrace_graph_count;
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_count && !*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_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 found = 0;
int type, not;
char *search;
bool exists;
int i;
if (ftrace_disabled)
return -ENODEV;
/* decode regex */
type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
if (not)
return -EINVAL;
search_len = strlen(search);
mutex_lock(&ftrace_lock);
do_for_each_ftrace_rec(pg, rec) {
if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
break;
if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
continue;
if (ftrace_match_record(rec, search, search_len, type)) {
/* ensure it is not already in the array */
exists = false;
for (i = 0; i < *idx; i++)
if (array[i] == rec->ip) {
exists = true;
break;
}
if (!exists)
array[(*idx)++] = rec->ip;
found = 1;
}
} while_for_each_ftrace_rec();
mutex_unlock(&ftrace_lock);
return found ? 0 : -EINVAL;
}
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 || cnt < 0)
return 0;
mutex_lock(&graph_lock);
if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
ret = -EBUSY;
goto out_unlock;
}
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,
};
#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("failures", 0444,
d_tracer, NULL, &ftrace_failures_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;
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);
}
/* disable interrupts to prevent kstop machine */
local_irq_save(flags);
ftrace_update_code(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;
if (ftrace_disabled)
return;
mutex_lock(&ftrace_lock);
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();
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 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(command) do { } while (0)
# define ftrace_shutdown(command) do { } while (0)
# define ftrace_startup_sysctl() do { } while (0)
# define ftrace_shutdown_sysctl() do { } while (0)
#endif /* CONFIG_DYNAMIC_FTRACE */
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();
}
/**
* 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;
if (unlikely(ftrace_disabled))
return -1;
mutex_lock(&ftrace_lock);
ret = __register_ftrace_function(ops);
ftrace_startup(0);
mutex_unlock(&ftrace_lock);
return ret;
}
/**
* 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);
ftrace_shutdown(0);
mutex_unlock(&ftrace_lock);
return ret;
}
int
ftrace_enable_sysctl(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
mutex_lock(&ftrace_lock);
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_list != &ftrace_list_end) {
if (ftrace_list->next == &ftrace_list_end)
ftrace_trace_function = ftrace_list->func;
else
ftrace_trace_function = ftrace_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(struct rq *__rq, 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_task(idle_task(cpu));
}
do {
ret = alloc_retstack_tasklist(ret_stack_list);
} while (ret == -EAGAIN);
if (!ret) {
ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
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;
ftrace_startup(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--;
unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
ftrace_graph_entry = ftrace_graph_entry_stub;
ftrace_shutdown(FTRACE_STOP_FUNC_RET);
unregister_pm_notifier(&ftrace_suspend_notifier);
out:
mutex_unlock(&ftrace_lock);
}
/* 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;
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;
t->curr_ret_stack = -1;
atomic_set(&t->tracing_graph_pause, 0);
atomic_set(&t->trace_overrun, 0);
t->ftrace_timestamp = 0;
/* make curr_ret_stack visable before we add the ret_stack */
smp_wmb();
t->ret_stack = 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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