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linux-sg2042/kernel/trace/ftrace.c

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// SPDX-License-Identifier: GPL-2.0
/*
* 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 Nadia Yvette Chambers
*/
#include <linux/stop_machine.h>
#include <linux/clocksource.h>
#include <linux/sched/task.h>
#include <linux/kallsyms.h>
#include <linux/security.h>
#include <linux/seq_file.h>
#include <linux/tracefs.h>
#include <linux/hardirq.h>
#include <linux/kthread.h>
#include <linux/uaccess.h>
#include <linux/bsearch.h>
#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/sysctl.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/sort.h>
#include <linux/list.h>
#include <linux/hash.h>
#include <linux/rcupdate.h>
#include <linux/kprobes.h>
#include <trace/events/sched.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include "ftrace_internal.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_DEFAULT_BITS 10
#define FTRACE_HASH_MAX_BITS 12
#ifdef CONFIG_DYNAMIC_FTRACE
#define INIT_OPS_HASH(opsname) \
.func_hash = &opsname.local_hash, \
.local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
#else
#define INIT_OPS_HASH(opsname)
#endif
enum {
FTRACE_MODIFY_ENABLE_FL = (1 << 0),
FTRACE_MODIFY_MAY_SLEEP_FL = (1 << 1),
};
struct ftrace_ops ftrace_list_end __read_mostly = {
.func = ftrace_stub,
.flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
INIT_OPS_HASH(ftrace_list_end)
};
/* ftrace_enabled is a method to turn ftrace on or off */
int ftrace_enabled __read_mostly;
static int last_ftrace_enabled;
/* Current function tracing op */
struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
/* What to set function_trace_op to */
static struct ftrace_ops *set_function_trace_op;
static bool ftrace_pids_enabled(struct ftrace_ops *ops)
{
struct trace_array *tr;
if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
return false;
tr = ops->private;
return tr->function_pids != NULL;
}
static void ftrace_update_trampoline(struct ftrace_ops *ops);
/*
* ftrace_disabled is set when an anomaly is discovered.
* ftrace_disabled is much stronger than ftrace_enabled.
*/
static int ftrace_disabled __read_mostly;
DEFINE_MUTEX(ftrace_lock);
struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
struct ftrace_ops global_ops;
#if ARCH_SUPPORTS_FTRACE_OPS
static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs);
#else
/* See comment below, where ftrace_ops_list_func is defined */
static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
#endif
static inline void ftrace_ops_init(struct ftrace_ops *ops)
{
#ifdef CONFIG_DYNAMIC_FTRACE
if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
mutex_init(&ops->local_hash.regex_lock);
ops->func_hash = &ops->local_hash;
ops->flags |= FTRACE_OPS_FL_INITIALIZED;
}
#endif
}
static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
struct trace_array *tr = op->private;
if (tr && this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid))
return;
op->saved_func(ip, parent_ip, op, regs);
}
static void ftrace_sync(struct work_struct *work)
{
/*
* This function is just a stub to implement a hard force
* of synchronize_rcu(). This requires synchronizing
* tasks even in userspace and idle.
*
* Yes, function tracing is rude.
*/
}
static void ftrace_sync_ipi(void *data)
{
/* Probably not needed, but do it anyway */
smp_rmb();
}
static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
{
/*
* If this is a dynamic, RCU, or per CPU ops, or we force list func,
* then it needs to call the list anyway.
*/
if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
FTRACE_FORCE_LIST_FUNC)
return ftrace_ops_list_func;
return ftrace_ops_get_func(ops);
}
static void update_ftrace_function(void)
{
ftrace_func_t func;
/*
* Prepare the ftrace_ops that the arch callback will use.
* If there's only one ftrace_ops registered, the ftrace_ops_list
* will point to the ops we want.
*/
set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
lockdep_is_held(&ftrace_lock));
/* If there's no ftrace_ops registered, just call the stub function */
if (set_function_trace_op == &ftrace_list_end) {
func = ftrace_stub;
/*
* If we are at the end of the list and this ops is
* recursion safe and not dynamic and the arch supports passing ops,
* then have the mcount trampoline call the function directly.
*/
} else if (rcu_dereference_protected(ftrace_ops_list->next,
lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
func = ftrace_ops_get_list_func(ftrace_ops_list);
} else {
/* Just use the default ftrace_ops */
set_function_trace_op = &ftrace_list_end;
func = ftrace_ops_list_func;
}
update_function_graph_func();
/* If there's no change, then do nothing more here */
if (ftrace_trace_function == func)
return;
/*
* If we are using the list function, it doesn't care
* about the function_trace_ops.
*/
if (func == ftrace_ops_list_func) {
ftrace_trace_function = func;
/*
* Don't even bother setting function_trace_ops,
* it would be racy to do so anyway.
*/
return;
}
#ifndef CONFIG_DYNAMIC_FTRACE
/*
* For static tracing, we need to be a bit more careful.
* The function change takes affect immediately. Thus,
* we need to coorditate the setting of the function_trace_ops
* with the setting of the ftrace_trace_function.
*
* Set the function to the list ops, which will call the
* function we want, albeit indirectly, but it handles the
* ftrace_ops and doesn't depend on function_trace_op.
*/
ftrace_trace_function = ftrace_ops_list_func;
/*
* Make sure all CPUs see this. Yes this is slow, but static
* tracing is slow and nasty to have enabled.
*/
schedule_on_each_cpu(ftrace_sync);
/* Now all cpus are using the list ops. */
function_trace_op = set_function_trace_op;
/* Make sure the function_trace_op is visible on all CPUs */
smp_wmb();
/* Nasty way to force a rmb on all cpus */
smp_call_function(ftrace_sync_ipi, NULL, 1);
/* OK, we are all set to update the ftrace_trace_function now! */
#endif /* !CONFIG_DYNAMIC_FTRACE */
ftrace_trace_function = func;
}
static void add_ftrace_ops(struct ftrace_ops __rcu **list,
struct ftrace_ops *ops)
{
rcu_assign_pointer(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 __rcu **list,
struct ftrace_ops *ops)
{
struct ftrace_ops **p;
/*
* If we are removing the last function, then simply point
* to the ftrace_stub.
*/
if (rcu_dereference_protected(*list,
lockdep_is_held(&ftrace_lock)) == ops &&
rcu_dereference_protected(ops->next,
lockdep_is_held(&ftrace_lock)) == &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 void ftrace_update_trampoline(struct ftrace_ops *ops);
int __register_ftrace_function(struct ftrace_ops *ops)
{
if (ops->flags & FTRACE_OPS_FL_DELETED)
return -EINVAL;
if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
return -EBUSY;
#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
/*
* If the ftrace_ops specifies SAVE_REGS, then it only can be used
* if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
* Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
*/
if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
!(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
return -EINVAL;
if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
#endif
if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
return -EBUSY;
if (!core_kernel_data((unsigned long)ops))
ops->flags |= FTRACE_OPS_FL_DYNAMIC;
add_ftrace_ops(&ftrace_ops_list, ops);
/* Always save the function, and reset at unregistering */
ops->saved_func = ops->func;
if (ftrace_pids_enabled(ops))
ops->func = ftrace_pid_func;
ftrace_update_trampoline(ops);
if (ftrace_enabled)
update_ftrace_function();
return 0;
}
int __unregister_ftrace_function(struct ftrace_ops *ops)
{
int ret;
if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
return -EBUSY;
ret = remove_ftrace_ops(&ftrace_ops_list, ops);
if (ret < 0)
return ret;
if (ftrace_enabled)
update_ftrace_function();
ops->func = ops->saved_func;
return 0;
}
static void ftrace_update_pid_func(void)
{
struct ftrace_ops *op;
/* Only do something if we are tracing something */
if (ftrace_trace_function == ftrace_stub)
return;
do_for_each_ftrace_op(op, ftrace_ops_list) {
if (op->flags & FTRACE_OPS_FL_PID) {
op->func = ftrace_pids_enabled(op) ?
ftrace_pid_func : op->saved_func;
ftrace_update_trampoline(op);
}
} while_for_each_ftrace_op(op);
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_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_BITS 10
#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
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(const void *p1, const void *p2)
{
const struct ftrace_profile *a = p1;
const 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(const void *p1, const void *p2)
{
const struct ftrace_profile *a = p1;
const 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_puts(m, " Function "
"Hit Time Avg s^2\n"
" -------- "
"--- ---- --- ---\n");
#else
seq_puts(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;
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
avg = div64_ul(rec->time, rec->counter);
if (tracing_thresh && (avg < tracing_thresh))
goto out;
#endif
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
seq_printf(m, " %-30.30s %10lu", str, rec->counter);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
seq_puts(m, " ");
/* Sample standard deviation (s^2) */
if (rec->counter <= 1)
stddev = 0;
else {
/*
* Apply Welford's method:
* s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
*/
stddev = rec->counter * rec->time_squared -
rec->time * rec->time;
/*
* Divide only 1000 for ns^2 -> us^2 conversion.
* trace_print_graph_duration will divide 1000 again.
*/
stddev = div64_ul(stddev,
rec->counter * (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 = 1; 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);
}
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 = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
if (!stat->hash)
return -ENOMEM;
/* 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_possible_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;
unsigned long key;
key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
hhd = &stat->hash[key];
if (hlist_empty(hhd))
return NULL;
hlist_for_each_entry_rcu_notrace(rec, 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_HASH_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_ops *ops, struct pt_regs *regs)
{
struct ftrace_profile_stat *stat;
struct ftrace_profile *rec;
unsigned long flags;
if (!ftrace_profile_enabled)
return;
local_irq_save(flags);
stat = this_cpu_ptr(&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 bool fgraph_graph_time = true;
void ftrace_graph_graph_time_control(bool enable)
{
fgraph_graph_time = enable;
}
static int profile_graph_entry(struct ftrace_graph_ent *trace)
{
struct ftrace_ret_stack *ret_stack;
function_profile_call(trace->func, 0, NULL, NULL);
/* If function graph is shutting down, ret_stack can be NULL */
if (!current->ret_stack)
return 0;
ret_stack = ftrace_graph_get_ret_stack(current, 0);
if (ret_stack)
ret_stack->subtime = 0;
return 1;
}
static void profile_graph_return(struct ftrace_graph_ret *trace)
{
struct ftrace_ret_stack *ret_stack;
struct ftrace_profile_stat *stat;
unsigned long long calltime;
struct ftrace_profile *rec;
unsigned long flags;
local_irq_save(flags);
stat = this_cpu_ptr(&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 (!fgraph_graph_time) {
/* Append this call time to the parent time to subtract */
ret_stack = ftrace_graph_get_ret_stack(current, 1);
if (ret_stack)
ret_stack->subtime += calltime;
ret_stack = ftrace_graph_get_ret_stack(current, 0);
if (ret_stack && ret_stack->subtime < calltime)
calltime -= ret_stack->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 struct fgraph_ops fprofiler_ops = {
.entryfunc = &profile_graph_entry,
.retfunc = &profile_graph_return,
};
static int register_ftrace_profiler(void)
{
return register_ftrace_graph(&fprofiler_ops);
}
static void unregister_ftrace_profiler(void)
{
unregister_ftrace_graph(&fprofiler_ops);
}
#else
static struct ftrace_ops ftrace_profile_ops __read_mostly = {
.func = function_profile_call,
.flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
INIT_OPS_HASH(ftrace_profile_ops)
};
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_rcu.
*/
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_tracefs(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);
name = kasprintf(GFP_KERNEL, "function%d", cpu);
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;
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 = tracefs_create_file("function_profile_enabled", 0644,
d_tracer, NULL, &ftrace_profile_fops);
if (!entry)
pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
}
#else /* CONFIG_FUNCTION_PROFILER */
static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
{
}
#endif /* CONFIG_FUNCTION_PROFILER */
#ifdef CONFIG_DYNAMIC_FTRACE
static struct ftrace_ops *removed_ops;
/*
* Set when doing a global update, like enabling all recs or disabling them.
* It is not set when just updating a single ftrace_ops.
*/
static bool update_all_ops;
#ifndef CONFIG_FTRACE_MCOUNT_RECORD
# error Dynamic ftrace depends on MCOUNT_RECORD
#endif
struct ftrace_func_probe {
struct ftrace_probe_ops *probe_ops;
struct ftrace_ops ops;
struct trace_array *tr;
struct list_head list;
void *data;
int ref;
};
/*
* 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)
struct ftrace_ops global_ops = {
.func = ftrace_stub,
.local_hash.notrace_hash = EMPTY_HASH,
.local_hash.filter_hash = EMPTY_HASH,
INIT_OPS_HASH(global_ops)
.flags = FTRACE_OPS_FL_RECURSION_SAFE |
FTRACE_OPS_FL_INITIALIZED |
FTRACE_OPS_FL_PID,
};
/*
* Used by the stack undwinder to know about dynamic ftrace trampolines.
*/
struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
{
struct ftrace_ops *op = NULL;
/*
* Some of the ops may be dynamically allocated,
* they are freed after a synchronize_rcu().
*/
preempt_disable_notrace();
do_for_each_ftrace_op(op, ftrace_ops_list) {
/*
* This is to check for dynamically allocated trampolines.
* Trampolines that are in kernel text will have
* core_kernel_text() return true.
*/
if (op->trampoline && op->trampoline_size)
if (addr >= op->trampoline &&
addr < op->trampoline + op->trampoline_size) {
preempt_enable_notrace();
return op;
}
} while_for_each_ftrace_op(op);
preempt_enable_notrace();
return NULL;
}
/*
* This is used by __kernel_text_address() to return true if the
* address is on a dynamically allocated trampoline that would
* not return true for either core_kernel_text() or
* is_module_text_address().
*/
bool is_ftrace_trampoline(unsigned long addr)
{
return ftrace_ops_trampoline(addr) != NULL;
}
struct ftrace_page {
struct ftrace_page *next;
struct dyn_ftrace *records;
int index;
int size;
};
#define ENTRY_SIZE sizeof(struct dyn_ftrace)
#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
static struct ftrace_page *ftrace_pages_start;
static struct ftrace_page *ftrace_pages;
static __always_inline unsigned long
ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
{
if (hash->size_bits > 0)
return hash_long(ip, hash->size_bits);
return 0;
}
/* Only use this function if ftrace_hash_empty() has already been tested */
static __always_inline 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;
key = ftrace_hash_key(hash, ip);
hhd = &hash->buckets[key];
hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
if (entry->ip == ip)
return entry;
}
return NULL;
}
/**
* ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
* @hash: The hash to look at
* @ip: The instruction pointer to test
*
* Search a given @hash to see if a given instruction pointer (@ip)
* exists in it.
*
* Returns the entry that holds the @ip if found. NULL otherwise.
*/
struct ftrace_func_entry *
ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
{
if (ftrace_hash_empty(hash))
return NULL;
return __ftrace_lookup_ip(hash, ip);
}
static void __add_hash_entry(struct ftrace_hash *hash,
struct ftrace_func_entry *entry)
{
struct hlist_head *hhd;
unsigned long key;
key = ftrace_hash_key(hash, entry->ip);
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_rcu(&entry->hlist);
hash->count--;
}
static void ftrace_hash_clear(struct ftrace_hash *hash)
{
struct hlist_head *hhd;
struct hlist_node *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, tn, hhd, hlist)
free_hash_entry(hash, entry);
}
FTRACE_WARN_ON(hash->count);
}
static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
{
list_del(&ftrace_mod->list);
kfree(ftrace_mod->module);
kfree(ftrace_mod->func);
kfree(ftrace_mod);
}
static void clear_ftrace_mod_list(struct list_head *head)
{
struct ftrace_mod_load *p, *n;
/* stack tracer isn't supported yet */
if (!head)
return;
mutex_lock(&ftrace_lock);
list_for_each_entry_safe(p, n, head, list)
free_ftrace_mod(p);
mutex_unlock(&ftrace_lock);
}
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(&hash->rcu, __free_ftrace_hash_rcu);
}
void ftrace_free_filter(struct ftrace_ops *ops)
{
ftrace_ops_init(ops);
free_ftrace_hash(ops->func_hash->filter_hash);
free_ftrace_hash(ops->func_hash->notrace_hash);
}
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 = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
if (!hash->buckets) {
kfree(hash);
return NULL;
}
hash->size_bits = size_bits;
return hash;
}
static int ftrace_add_mod(struct trace_array *tr,
const char *func, const char *module,
int enable)
{
struct ftrace_mod_load *ftrace_mod;
struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
if (!ftrace_mod)
return -ENOMEM;
ftrace_mod->func = kstrdup(func, GFP_KERNEL);
ftrace_mod->module = kstrdup(module, GFP_KERNEL);
ftrace_mod->enable = enable;
if (!ftrace_mod->func || !ftrace_mod->module)
goto out_free;
list_add(&ftrace_mod->list, mod_head);
return 0;
out_free:
free_ftrace_mod(ftrace_mod);
return -ENOMEM;
}
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;
int size;
int ret;
int i;
new_hash = alloc_ftrace_hash(size_bits);
if (!new_hash)
return NULL;
if (hash)
new_hash->flags = hash->flags;
/* Empty hash? */
if (ftrace_hash_empty(hash))
return new_hash;
size = 1 << hash->size_bits;
for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &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_modify(struct ftrace_ops *ops, int filter_hash);
static void
ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
struct ftrace_hash *new_hash);
static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
{
struct ftrace_func_entry *entry;
struct ftrace_hash *new_hash;
struct hlist_head *hhd;
struct hlist_node *tn;
int bits = 0;
int i;
/*
* 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;
new_hash = alloc_ftrace_hash(bits);
if (!new_hash)
return NULL;
new_hash->flags = src->flags;
size = 1 << src->size_bits;
for (i = 0; i < size; i++) {
hhd = &src->buckets[i];
hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
remove_hash_entry(src, entry);
__add_hash_entry(new_hash, entry);
}
}
return new_hash;
}
static struct ftrace_hash *
__ftrace_hash_move(struct ftrace_hash *src)
{
int size = src->count;
/*
* If the new source is empty, just return the empty_hash.
*/
if (ftrace_hash_empty(src))
return EMPTY_HASH;
return dup_hash(src, size);
}
static int
ftrace_hash_move(struct ftrace_ops *ops, int enable,
struct ftrace_hash **dst, struct ftrace_hash *src)
{
struct ftrace_hash *new_hash;
int ret;
/* Reject setting notrace hash on IPMODIFY ftrace_ops */
if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
return -EINVAL;
new_hash = __ftrace_hash_move(src);
if (!new_hash)
return -ENOMEM;
/* Make sure this can be applied if it is IPMODIFY ftrace_ops */
if (enable) {
/* IPMODIFY should be updated only when filter_hash updating */
ret = ftrace_hash_ipmodify_update(ops, new_hash);
if (ret < 0) {
free_ftrace_hash(new_hash);
return ret;
}
}
/*
* Remove the current set, update the hash and add
* them back.
*/
ftrace_hash_rec_disable_modify(ops, enable);
rcu_assign_pointer(*dst, new_hash);
ftrace_hash_rec_enable_modify(ops, enable);
return 0;
}
static bool hash_contains_ip(unsigned long ip,
struct ftrace_ops_hash *hash)
{
/*
* The function record is a match if it exists in the filter
* hash and not in the notrace hash. Note, an emty hash is
* considered a match for the filter hash, but an empty
* notrace hash is considered not in the notrace hash.
*/
return (ftrace_hash_empty(hash->filter_hash) ||
__ftrace_lookup_ip(hash->filter_hash, ip)) &&
(ftrace_hash_empty(hash->notrace_hash) ||
!__ftrace_lookup_ip(hash->notrace_hash, ip));
}
/*
* 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().
*/
int
ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
{
struct ftrace_ops_hash hash;
int ret;
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
/*
* There's a small race when adding ops that the ftrace handler
* that wants regs, may be called without them. We can not
* allow that handler to be called if regs is NULL.
*/
if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
return 0;
#endif
rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
if (hash_contains_ip(ip, &hash))
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 int ftrace_cmp_recs(const void *a, const void *b)
{
const struct dyn_ftrace *key = a;
const struct dyn_ftrace *rec = b;
if (key->flags < rec->ip)
return -1;
if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
return 1;
return 0;
}
static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
{
struct ftrace_page *pg;
struct dyn_ftrace *rec = NULL;
struct dyn_ftrace key;
key.ip = start;
key.flags = end; /* overload flags, as it is unsigned long */
for (pg = ftrace_pages_start; pg; pg = pg->next) {
if (end < pg->records[0].ip ||
start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
continue;
rec = bsearch(&key, pg->records, pg->index,
sizeof(struct dyn_ftrace),
ftrace_cmp_recs);
}
return rec;
}
/**
* ftrace_location_range - return the first address of a traced location
* if it touches the given ip range
* @start: start of range to search.
* @end: end of range to search (inclusive). @end points to the last byte
* to check.
*
* Returns rec->ip if the related ftrace location is a least partly within
* the given address range. That is, the first address of the instruction
* that is either a NOP or call to the function tracer. It checks the ftrace
* internal tables to determine if the address belongs or not.
*/
unsigned long ftrace_location_range(unsigned long start, unsigned long end)
{
struct dyn_ftrace *rec;
rec = lookup_rec(start, end);
if (rec)
return rec->ip;
return 0;
}
/**
* ftrace_location - return true if the ip giving is a traced location
* @ip: the instruction pointer to check
*
* Returns rec->ip if @ip given is a pointer to a ftrace location.
* That is, the instruction that is either a NOP or call to
* the function tracer. It checks the ftrace internal tables to
* determine if the address belongs or not.
*/
unsigned long ftrace_location(unsigned long ip)
{
return ftrace_location_range(ip, ip);
}
/**
* ftrace_text_reserved - return true if range contains an ftrace location
* @start: start of range to search
* @end: end of range to search (inclusive). @end points to the last byte to check.
*
* Returns 1 if @start and @end contains a ftrace location.
* That is, the instruction that is either a NOP or call to
* the function tracer. It checks the ftrace internal tables to
* determine if the address belongs or not.
*/
int ftrace_text_reserved(const void *start, const void *end)
{
unsigned long ret;
ret = ftrace_location_range((unsigned long)start,
(unsigned long)end);
return (int)!!ret;
}
/* Test if ops registered to this rec needs regs */
static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
{
struct ftrace_ops *ops;
bool keep_regs = false;
for (ops = ftrace_ops_list;
ops != &ftrace_list_end; ops = ops->next) {
/* pass rec in as regs to have non-NULL val */
if (ftrace_ops_test(ops, rec->ip, rec)) {
if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
keep_regs = true;
break;
}
}
}
return keep_regs;
}
static struct ftrace_ops *
ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
static struct ftrace_ops *
ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
static bool __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;
bool update = false;
int count = 0;
int all = false;
/* Only update if the ops has been registered */
if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
return false;
/*
* 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->func_hash->filter_hash;
other_hash = ops->func_hash->notrace_hash;
if (ftrace_hash_empty(hash))
all = true;
} else {
inc = !inc;
hash = ops->func_hash->notrace_hash;
other_hash = ops->func_hash->filter_hash;
/*
* If the notrace hash has no items,
* then there's nothing to do.
*/
if (ftrace_hash_empty(hash))
return false;
}
do_for_each_ftrace_rec(pg, rec) {
int in_other_hash = 0;
int in_hash = 0;
int match = 0;
if (rec->flags & FTRACE_FL_DISABLED)
continue;
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 = !!ftrace_lookup_ip(hash, rec->ip);
in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
/*
* If filter_hash is set, we want to match all functions
* that are in the hash but not in the other hash.
*
* If filter_hash is not set, then we are decrementing.
* That means we match anything that is in the hash
* and also in the other_hash. That is, we need to turn
* off functions in the other hash because they are disabled
* by this hash.
*/
if (filter_hash && in_hash && !in_other_hash)
match = 1;
else if (!filter_hash && in_hash &&
(in_other_hash || ftrace_hash_empty(other_hash)))
match = 1;
}
if (!match)
continue;
if (inc) {
rec->flags++;
if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
return false;
if (ops->flags & FTRACE_OPS_FL_DIRECT)
rec->flags |= FTRACE_FL_DIRECT;
/*
* If there's only a single callback registered to a
* function, and the ops has a trampoline registered
* for it, then we can call it directly.
*/
if (ftrace_rec_count(rec) == 1 && ops->trampoline)
rec->flags |= FTRACE_FL_TRAMP;
else
/*
* If we are adding another function callback
* to this function, and the previous had a
* custom trampoline in use, then we need to go
* back to the default trampoline.
*/
rec->flags &= ~FTRACE_FL_TRAMP;
/*
* If any ops wants regs saved for this function
* then all ops will get saved regs.
*/
if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
rec->flags |= FTRACE_FL_REGS;
} else {
if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
return false;
rec->flags--;
/*
* Only the internal direct_ops should have the
* DIRECT flag set. Thus, if it is removing a
* function, then that function should no longer
* be direct.
*/
if (ops->flags & FTRACE_OPS_FL_DIRECT)
rec->flags &= ~FTRACE_FL_DIRECT;
/*
* If the rec had REGS enabled and the ops that is
* being removed had REGS set, then see if there is
* still any ops for this record that wants regs.
* If not, we can stop recording them.
*/
if (ftrace_rec_count(rec) > 0 &&
rec->flags & FTRACE_FL_REGS &&
ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
if (!test_rec_ops_needs_regs(rec))
rec->flags &= ~FTRACE_FL_REGS;
}
/*
* The TRAMP needs to be set only if rec count
* is decremented to one, and the ops that is
* left has a trampoline. As TRAMP can only be
* enabled if there is only a single ops attached
* to it.
*/
if (ftrace_rec_count(rec) == 1 &&
ftrace_find_tramp_ops_any(rec))
rec->flags |= FTRACE_FL_TRAMP;
else
rec->flags &= ~FTRACE_FL_TRAMP;
/*
* flags will be cleared in ftrace_check_record()
* if rec count is zero.
*/
}
count++;
/* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
/* Shortcut, if we handled all records, we are done. */
if (!all && count == hash->count)
return update;
} while_for_each_ftrace_rec();
return update;
}
static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
int filter_hash)
{
return __ftrace_hash_rec_update(ops, filter_hash, 0);
}
static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
int filter_hash)
{
return __ftrace_hash_rec_update(ops, filter_hash, 1);
}
static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
int filter_hash, int inc)
{
struct ftrace_ops *op;
__ftrace_hash_rec_update(ops, filter_hash, inc);
if (ops->func_hash != &global_ops.local_hash)
return;
/*
* If the ops shares the global_ops hash, then we need to update
* all ops that are enabled and use this hash.
*/
do_for_each_ftrace_op(op, ftrace_ops_list) {
/* Already done */
if (op == ops)
continue;
if (op->func_hash == &global_ops.local_hash)
__ftrace_hash_rec_update(op, filter_hash, inc);
} while_for_each_ftrace_op(op);
}
static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
int filter_hash)
{
ftrace_hash_rec_update_modify(ops, filter_hash, 0);
}
static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
int filter_hash)
{
ftrace_hash_rec_update_modify(ops, filter_hash, 1);
}
/*
* Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
* or no-needed to update, -EBUSY if it detects a conflict of the flag
* on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
* Note that old_hash and new_hash has below meanings
* - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
* - If the hash is EMPTY_HASH, it hits nothing
* - Anything else hits the recs which match the hash entries.
*/
static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
struct ftrace_hash *old_hash,
struct ftrace_hash *new_hash)
{
struct ftrace_page *pg;
struct dyn_ftrace *rec, *end = NULL;
int in_old, in_new;
/* Only update if the ops has been registered */
if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
return 0;
if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
return 0;
/*
* Since the IPMODIFY is a very address sensitive action, we do not
* allow ftrace_ops to set all functions to new hash.
*/
if (!new_hash || !old_hash)
return -EINVAL;
/* Update rec->flags */
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_DISABLED)
continue;
/* We need to update only differences of filter_hash */
in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
if (in_old == in_new)
continue;
if (in_new) {
/* New entries must ensure no others are using it */
if (rec->flags & FTRACE_FL_IPMODIFY)
goto rollback;
rec->flags |= FTRACE_FL_IPMODIFY;
} else /* Removed entry */
rec->flags &= ~FTRACE_FL_IPMODIFY;
} while_for_each_ftrace_rec();
return 0;
rollback:
end = rec;
/* Roll back what we did above */
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_DISABLED)
continue;
if (rec == end)
goto err_out;
in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
if (in_old == in_new)
continue;
if (in_new)
rec->flags &= ~FTRACE_FL_IPMODIFY;
else
rec->flags |= FTRACE_FL_IPMODIFY;
} while_for_each_ftrace_rec();
err_out:
return -EBUSY;
}
static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
{
struct ftrace_hash *hash = ops->func_hash->filter_hash;
if (ftrace_hash_empty(hash))
hash = NULL;
return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
}
/* Disabling always succeeds */
static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
{
struct ftrace_hash *hash = ops->func_hash->filter_hash;
if (ftrace_hash_empty(hash))
hash = NULL;
__ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
}
static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
struct ftrace_hash *new_hash)
{
struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
if (ftrace_hash_empty(old_hash))
old_hash = NULL;
if (ftrace_hash_empty(new_hash))
new_hash = NULL;
return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
}
static void print_ip_ins(const char *fmt, const 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]);
}
enum ftrace_bug_type ftrace_bug_type;
const void *ftrace_expected;
static void print_bug_type(void)
{
switch (ftrace_bug_type) {
case FTRACE_BUG_UNKNOWN:
break;
case FTRACE_BUG_INIT:
pr_info("Initializing ftrace call sites\n");
break;
case FTRACE_BUG_NOP:
pr_info("Setting ftrace call site to NOP\n");
break;
case FTRACE_BUG_CALL:
pr_info("Setting ftrace call site to call ftrace function\n");
break;
case FTRACE_BUG_UPDATE:
pr_info("Updating ftrace call site to call a different ftrace function\n");
break;
}
}
/**
* ftrace_bug - report and shutdown function tracer
* @failed: The failed type (EFAULT, EINVAL, EPERM)
* @rec: The record that failed
*
* The arch code that enables or disables the function tracing
* can call ftrace_bug() when it has detected a problem in
* modifying the code. @failed should be one of either:
* EFAULT - if the problem happens on reading the @ip address
* EINVAL - if what is read at @ip is not what was expected
* EPERM - if the problem happens on writing to the @ip address
*/
void ftrace_bug(int failed, struct dyn_ftrace *rec)
{
unsigned long ip = rec ? rec->ip : 0;
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);
pr_cont("\n");
if (ftrace_expected) {
print_ip_ins(" expected: ", ftrace_expected);
pr_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);
}
print_bug_type();
if (rec) {
struct ftrace_ops *ops = NULL;
pr_info("ftrace record flags: %lx\n", rec->flags);
pr_cont(" (%ld)%s", ftrace_rec_count(rec),
rec->flags & FTRACE_FL_REGS ? " R" : " ");
if (rec->flags & FTRACE_FL_TRAMP_EN) {
ops = ftrace_find_tramp_ops_any(rec);
if (ops) {
do {
pr_cont("\ttramp: %pS (%pS)",
(void *)ops->trampoline,
(void *)ops->func);
ops = ftrace_find_tramp_ops_next(rec, ops);
} while (ops);
} else
pr_cont("\ttramp: ERROR!");
}
ip = ftrace_get_addr_curr(rec);
pr_cont("\n expected tramp: %lx\n", ip);
}
}
static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
{
unsigned long flag = 0UL;
ftrace_bug_type = FTRACE_BUG_UNKNOWN;
if (rec->flags & FTRACE_FL_DISABLED)
return FTRACE_UPDATE_IGNORE;
/*
* If we are updating calls:
*
* 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 calls, then disable all records that
* are enabled.
*/
if (enable && ftrace_rec_count(rec))
flag = FTRACE_FL_ENABLED;
/*
* If enabling and the REGS flag does not match the REGS_EN, or
* the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
* this record. Set flags to fail the compare against ENABLED.
* Same for direct calls.
*/
if (flag) {
if (!(rec->flags & FTRACE_FL_REGS) !=
!(rec->flags & FTRACE_FL_REGS_EN))
flag |= FTRACE_FL_REGS;
if (!(rec->flags & FTRACE_FL_TRAMP) !=
!(rec->flags & FTRACE_FL_TRAMP_EN))
flag |= FTRACE_FL_TRAMP;
/*
* Direct calls are special, as count matters.
* We must test the record for direct, if the
* DIRECT and DIRECT_EN do not match, but only
* if the count is 1. That's because, if the
* count is something other than one, we do not
* want the direct enabled (it will be done via the
* direct helper). But if DIRECT_EN is set, and
* the count is not one, we need to clear it.
*/
if (ftrace_rec_count(rec) == 1) {
if (!(rec->flags & FTRACE_FL_DIRECT) !=
!(rec->flags & FTRACE_FL_DIRECT_EN))
flag |= FTRACE_FL_DIRECT;
} else if (rec->flags & FTRACE_FL_DIRECT_EN) {
flag |= FTRACE_FL_DIRECT;
}
}
/* If the state of this record hasn't changed, then do nothing */
if ((rec->flags & FTRACE_FL_ENABLED) == flag)
return FTRACE_UPDATE_IGNORE;
if (flag) {
/* Save off if rec is being enabled (for return value) */
flag ^= rec->flags & FTRACE_FL_ENABLED;
if (update) {
rec->flags |= FTRACE_FL_ENABLED;
if (flag & FTRACE_FL_REGS) {
if (rec->flags & FTRACE_FL_REGS)
rec->flags |= FTRACE_FL_REGS_EN;
else
rec->flags &= ~FTRACE_FL_REGS_EN;
}
if (flag & FTRACE_FL_TRAMP) {
if (rec->flags & FTRACE_FL_TRAMP)
rec->flags |= FTRACE_FL_TRAMP_EN;
else
rec->flags &= ~FTRACE_FL_TRAMP_EN;
}
if (flag & FTRACE_FL_DIRECT) {
/*
* If there's only one user (direct_ops helper)
* then we can call the direct function
* directly (no ftrace trampoline).
*/
if (ftrace_rec_count(rec) == 1) {
if (rec->flags & FTRACE_FL_DIRECT)
rec->flags |= FTRACE_FL_DIRECT_EN;
else
rec->flags &= ~FTRACE_FL_DIRECT_EN;
} else {
/*
* Can only call directly if there's
* only one callback to the function.
*/
rec->flags &= ~FTRACE_FL_DIRECT_EN;
}
}
}
/*
* If this record is being updated from a nop, then
* return UPDATE_MAKE_CALL.
* Otherwise,
* return UPDATE_MODIFY_CALL to tell the caller to convert
* from the save regs, to a non-save regs function or
* vice versa, or from a trampoline call.
*/
if (flag & FTRACE_FL_ENABLED) {
ftrace_bug_type = FTRACE_BUG_CALL;
return FTRACE_UPDATE_MAKE_CALL;
}
ftrace_bug_type = FTRACE_BUG_UPDATE;
return FTRACE_UPDATE_MODIFY_CALL;
}
if (update) {
/* If there's no more users, clear all flags */
if (!ftrace_rec_count(rec))
rec->flags = 0;
else
/*
* Just disable the record, but keep the ops TRAMP
* and REGS states. The _EN flags must be disabled though.
*/
rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
}
ftrace_bug_type = FTRACE_BUG_NOP;
return FTRACE_UPDATE_MAKE_NOP;
}
/**
* ftrace_update_record, set a record that now is tracing or not
* @rec: the record to update
* @enable: set to true if the record is tracing, false to force disable
*
* The records that represent all functions that can be traced need
* to be updated when tracing has been enabled.
*/
int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
{
return ftrace_check_record(rec, enable, true);
}
/**
* ftrace_test_record, check if the record has been enabled or not
* @rec: the record to test
* @enable: set to true to check if enabled, false if it is disabled
*
* The arch code may need to test if a record is already set to
* tracing to determine how to modify the function code that it
* represents.
*/
int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
{
return ftrace_check_record(rec, enable, false);
}
static struct ftrace_ops *
ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
{
struct ftrace_ops *op;
unsigned long ip = rec->ip;
do_for_each_ftrace_op(op, ftrace_ops_list) {
if (!op->trampoline)
continue;
if (hash_contains_ip(ip, op->func_hash))
return op;
} while_for_each_ftrace_op(op);
return NULL;
}
static struct ftrace_ops *
ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
struct ftrace_ops *op)
{
unsigned long ip = rec->ip;
while_for_each_ftrace_op(op) {
if (!op->trampoline)
continue;
if (hash_contains_ip(ip, op->func_hash))
return op;
}
return NULL;
}
static struct ftrace_ops *
ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
{
struct ftrace_ops *op;
unsigned long ip = rec->ip;
/*
* Need to check removed ops first.
* If they are being removed, and this rec has a tramp,
* and this rec is in the ops list, then it would be the
* one with the tramp.
*/
if (removed_ops) {
if (hash_contains_ip(ip, &removed_ops->old_hash))
return removed_ops;
}
/*
* Need to find the current trampoline for a rec.
* Now, a trampoline is only attached to a rec if there
* was a single 'ops' attached to it. But this can be called
* when we are adding another op to the rec or removing the
* current one. Thus, if the op is being added, we can
* ignore it because it hasn't attached itself to the rec
* yet.
*
* If an ops is being modified (hooking to different functions)
* then we don't care about the new functions that are being
* added, just the old ones (that are probably being removed).
*
* If we are adding an ops to a function that already is using
* a trampoline, it needs to be removed (trampolines are only
* for single ops connected), then an ops that is not being
* modified also needs to be checked.
*/
do_for_each_ftrace_op(op, ftrace_ops_list) {
if (!op->trampoline)
continue;
/*
* If the ops is being added, it hasn't gotten to
* the point to be removed from this tree yet.
*/
if (op->flags & FTRACE_OPS_FL_ADDING)
continue;
/*
* If the ops is being modified and is in the old
* hash, then it is probably being removed from this
* function.
*/
if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
hash_contains_ip(ip, &op->old_hash))
return op;
/*
* If the ops is not being added or modified, and it's
* in its normal filter hash, then this must be the one
* we want!
*/
if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
hash_contains_ip(ip, op->func_hash))
return op;
} while_for_each_ftrace_op(op);
return NULL;
}
static struct ftrace_ops *
ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
{
struct ftrace_ops *op;
unsigned long ip = rec->ip;
do_for_each_ftrace_op(op, ftrace_ops_list) {
/* pass rec in as regs to have non-NULL val */
if (hash_contains_ip(ip, op->func_hash))
return op;
} while_for_each_ftrace_op(op);
return NULL;
}
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
/* Protected by rcu_tasks for reading, and direct_mutex for writing */
static struct ftrace_hash *direct_functions = EMPTY_HASH;
static DEFINE_MUTEX(direct_mutex);
int ftrace_direct_func_count;
/*
* Search the direct_functions hash to see if the given instruction pointer
* has a direct caller attached to it.
*/
unsigned long ftrace_find_rec_direct(unsigned long ip)
{
struct ftrace_func_entry *entry;
entry = __ftrace_lookup_ip(direct_functions, ip);
if (!entry)
return 0;
return entry->direct;
}
static void call_direct_funcs(unsigned long ip, unsigned long pip,
struct ftrace_ops *ops, struct pt_regs *regs)
{
unsigned long addr;
addr = ftrace_find_rec_direct(ip);
if (!addr)
return;
arch_ftrace_set_direct_caller(regs, addr);
}
struct ftrace_ops direct_ops = {
.func = call_direct_funcs,
.flags = FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_RECURSION_SAFE
| FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
| FTRACE_OPS_FL_PERMANENT,
};
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
/**
* ftrace_get_addr_new - Get the call address to set to
* @rec: The ftrace record descriptor
*
* If the record has the FTRACE_FL_REGS set, that means that it
* wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
* is not not set, then it wants to convert to the normal callback.
*
* Returns the address of the trampoline to set to
*/
unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
{
struct ftrace_ops *ops;
unsigned long addr;
if ((rec->flags & FTRACE_FL_DIRECT) &&
(ftrace_rec_count(rec) == 1)) {
addr = ftrace_find_rec_direct(rec->ip);
if (addr)
return addr;
WARN_ON_ONCE(1);
}
/* Trampolines take precedence over regs */
if (rec->flags & FTRACE_FL_TRAMP) {
ops = ftrace_find_tramp_ops_new(rec);
if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
(void *)rec->ip, (void *)rec->ip, rec->flags);
/* Ftrace is shutting down, return anything */
return (unsigned long)FTRACE_ADDR;
}
return ops->trampoline;
}
if (rec->flags & FTRACE_FL_REGS)
return (unsigned long)FTRACE_REGS_ADDR;
else
return (unsigned long)FTRACE_ADDR;
}
/**
* ftrace_get_addr_curr - Get the call address that is already there
* @rec: The ftrace record descriptor
*
* The FTRACE_FL_REGS_EN is set when the record already points to
* a function that saves all the regs. Basically the '_EN' version
* represents the current state of the function.
*
* Returns the address of the trampoline that is currently being called
*/
unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
{
struct ftrace_ops *ops;
unsigned long addr;
/* Direct calls take precedence over trampolines */
if (rec->flags & FTRACE_FL_DIRECT_EN) {
addr = ftrace_find_rec_direct(rec->ip);
if (addr)
return addr;
WARN_ON_ONCE(1);
}
/* Trampolines take precedence over regs */
if (rec->flags & FTRACE_FL_TRAMP_EN) {
ops = ftrace_find_tramp_ops_curr(rec);
if (FTRACE_WARN_ON(!ops)) {
pr_warn("Bad trampoline accounting at: %p (%pS)\n",
(void *)rec->ip, (void *)rec->ip);
/* Ftrace is shutting down, return anything */
return (unsigned long)FTRACE_ADDR;
}
return ops->trampoline;
}
if (rec->flags & FTRACE_FL_REGS_EN)
return (unsigned long)FTRACE_REGS_ADDR;
else
return (unsigned long)FTRACE_ADDR;
}
static int
__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
{
unsigned long ftrace_old_addr;
unsigned long ftrace_addr;
int ret;
ftrace_addr = ftrace_get_addr_new(rec);
/* This needs to be done before we call ftrace_update_record */
ftrace_old_addr = ftrace_get_addr_curr(rec);
ret = ftrace_update_record(rec, enable);
ftrace_bug_type = FTRACE_BUG_UNKNOWN;
switch (ret) {
case FTRACE_UPDATE_IGNORE:
return 0;
case FTRACE_UPDATE_MAKE_CALL:
ftrace_bug_type = FTRACE_BUG_CALL;
return ftrace_make_call(rec, ftrace_addr);
case FTRACE_UPDATE_MAKE_NOP:
ftrace_bug_type = FTRACE_BUG_NOP;
return ftrace_make_nop(NULL, rec, ftrace_old_addr);
case FTRACE_UPDATE_MODIFY_CALL:
ftrace_bug_type = FTRACE_BUG_UPDATE;
return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
}
return -1; /* unknown ftrace bug */
}
void __weak ftrace_replace_code(int mod_flags)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
int failed;
if (unlikely(ftrace_disabled))
return;
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_DISABLED)
continue;
failed = __ftrace_replace_code(rec, enable);
if (failed) {
ftrace_bug(failed, rec);
/* Stop processing */
return;
}
if (schedulable)
cond_resched();
} while_for_each_ftrace_rec();
}
struct ftrace_rec_iter {
struct ftrace_page *pg;
int index;
};
/**
* ftrace_rec_iter_start, start up iterating over traced functions
*
* Returns an iterator handle that is used to iterate over all
* the records that represent address locations where functions
* are traced.
*
* May return NULL if no records are available.
*/
struct ftrace_rec_iter *ftrace_rec_iter_start(void)
{
/*
* We only use a single iterator.
* Protected by the ftrace_lock mutex.
*/
static struct ftrace_rec_iter ftrace_rec_iter;
struct ftrace_rec_iter *iter = &ftrace_rec_iter;
iter->pg = ftrace_pages_start;
iter->index = 0;
/* Could have empty pages */
while (iter->pg && !iter->pg->index)
iter->pg = iter->pg->next;
if (!iter->pg)
return NULL;
return iter;
}
/**
* ftrace_rec_iter_next, get the next record to process.
* @iter: The handle to the iterator.
*
* Returns the next iterator after the given iterator @iter.
*/
struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
{
iter->index++;
if (iter->index >= iter->pg->index) {
iter->pg = iter->pg->next;
iter->index = 0;
/* Could have empty pages */
while (iter->pg && !iter->pg->index)
iter->pg = iter->pg->next;
}
if (!iter->pg)
return NULL;
return iter;
}
/**
* ftrace_rec_iter_record, get the record at the iterator location
* @iter: The current iterator location
*
* Returns the record that the current @iter is at.
*/
struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
{
return &iter->pg->records[iter->index];
}
static int
ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
{
int ret;
if (unlikely(ftrace_disabled))
return 0;
ret = ftrace_init_nop(mod, rec);
if (ret) {
ftrace_bug_type = FTRACE_BUG_INIT;
ftrace_bug(ret, rec);
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;
}
void ftrace_modify_all_code(int command)
{
int update = command & FTRACE_UPDATE_TRACE_FUNC;
int mod_flags = 0;
int err = 0;
if (command & FTRACE_MAY_SLEEP)
mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
/*
* If the ftrace_caller calls a ftrace_ops func directly,
* we need to make sure that it only traces functions it
* expects to trace. When doing the switch of functions,
* we need to update to the ftrace_ops_list_func first
* before the transition between old and new calls are set,
* as the ftrace_ops_list_func will check the ops hashes
* to make sure the ops are having the right functions
* traced.
*/
if (update) {
err = ftrace_update_ftrace_func(ftrace_ops_list_func);
if (FTRACE_WARN_ON(err))
return;
}
if (command & FTRACE_UPDATE_CALLS)
ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
else if (command & FTRACE_DISABLE_CALLS)
ftrace_replace_code(mod_flags);
if (update && ftrace_trace_function != ftrace_ops_list_func) {
function_trace_op = set_function_trace_op;
smp_wmb();
/* If irqs are disabled, we are in stop machine */
if (!irqs_disabled())
smp_call_function(ftrace_sync_ipi, NULL, 1);
err = ftrace_update_ftrace_func(ftrace_trace_function);
if (FTRACE_WARN_ON(err))
return;
}
if (command & FTRACE_START_FUNC_RET)
err = ftrace_enable_ftrace_graph_caller();
else if (command & FTRACE_STOP_FUNC_RET)
err = ftrace_disable_ftrace_graph_caller();
FTRACE_WARN_ON(err);
}
static int __ftrace_modify_code(void *data)
{
int *command = data;
ftrace_modify_all_code(*command);
return 0;
}
/**
* ftrace_run_stop_machine, go back to the stop machine method
* @command: The command to tell ftrace what to do
*
* If an arch needs to fall back to the stop machine method, the
* it can call this function.
*/
void ftrace_run_stop_machine(int command)
{
stop_machine(__ftrace_modify_code, &command, NULL);
}
/**
* arch_ftrace_update_code, modify the code to trace or not trace
* @command: The command that needs to be done
*
* Archs can override this function if it does not need to
* run stop_machine() to modify code.
*/
void __weak arch_ftrace_update_code(int command)
{
ftrace_run_stop_machine(command);
}
static void ftrace_run_update_code(int command)
{
int ret;
ret = ftrace_arch_code_modify_prepare();
FTRACE_WARN_ON(ret);
if (ret)
return;
/*
* By default we use stop_machine() to modify the code.
* But archs can do what ever they want as long as it
* is safe. The stop_machine() is the safest, but also
* produces the most overhead.
*/
arch_ftrace_update_code(command);
ret = ftrace_arch_code_modify_post_process();
FTRACE_WARN_ON(ret);
}
static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
struct ftrace_ops_hash *old_hash)
{
ops->flags |= FTRACE_OPS_FL_MODIFYING;
ops->old_hash.filter_hash = old_hash->filter_hash;
ops->old_hash.notrace_hash = old_hash->notrace_hash;
ftrace_run_update_code(command);
ops->old_hash.filter_hash = NULL;
ops->old_hash.notrace_hash = NULL;
ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
}
static ftrace_func_t saved_ftrace_func;
static int ftrace_start_up;
void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
{
}
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_all(int command)
{
update_all_ops = true;
ftrace_startup_enable(command);
update_all_ops = false;
}
int ftrace_startup(struct ftrace_ops *ops, int command)
{
int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
ret = __register_ftrace_function(ops);
if (ret)
return ret;
ftrace_start_up++;
/*
* Note that ftrace probes uses this to start up
* and modify functions it will probe. But we still
* set the ADDING flag for modification, as probes
* do not have trampolines. If they add them in the
* future, then the probes will need to distinguish
* between adding and updating probes.
*/
ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
ret = ftrace_hash_ipmodify_enable(ops);
if (ret < 0) {
/* Rollback registration process */
__unregister_ftrace_function(ops);
ftrace_start_up--;
ops->flags &= ~FTRACE_OPS_FL_ENABLED;
return ret;
}
if (ftrace_hash_rec_enable(ops, 1))
command |= FTRACE_UPDATE_CALLS;
ftrace_startup_enable(command);
ops->flags &= ~FTRACE_OPS_FL_ADDING;
return 0;
}
int ftrace_shutdown(struct ftrace_ops *ops, int command)
{
int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
ret = __unregister_ftrace_function(ops);
if (ret)
return ret;
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);
/* Disabling ipmodify never fails */
ftrace_hash_ipmodify_disable(ops);
if (ftrace_hash_rec_disable(ops, 1))
command |= FTRACE_UPDATE_CALLS;
ops->flags &= ~FTRACE_OPS_FL_ENABLED;
if (saved_ftrace_func != ftrace_trace_function) {
saved_ftrace_func = ftrace_trace_function;
command |= FTRACE_UPDATE_TRACE_FUNC;
}
if (!command || !ftrace_enabled) {
/*
* If these are dynamic or per_cpu ops, they still
* need their data freed. Since, function tracing is
* not currently active, we can just free them
* without synchronizing all CPUs.
*/
if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
goto free_ops;
return 0;
}
/*
* If the ops uses a trampoline, then it needs to be
* tested first on update.
*/
ops->flags |= FTRACE_OPS_FL_REMOVING;
removed_ops = ops;
/* The trampoline logic checks the old hashes */
ops->old_hash.filter_hash = ops->func_hash->filter_hash;
ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
ftrace_run_update_code(command);
/*
* If there's no more ops registered with ftrace, run a
* sanity check to make sure all rec flags are cleared.
*/
if (rcu_dereference_protected(ftrace_ops_list,
lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
struct ftrace_page *pg;
struct dyn_ftrace *rec;
do_for_each_ftrace_rec(pg, rec) {
if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
pr_warn(" %pS flags:%lx\n",
(void *)rec->ip, rec->flags);
} while_for_each_ftrace_rec();
}
ops->old_hash.filter_hash = NULL;
ops->old_hash.notrace_hash = NULL;
removed_ops = NULL;
ops->flags &= ~FTRACE_OPS_FL_REMOVING;
/*
* Dynamic ops may be freed, we must make sure that all
* callers are done before leaving this function.
* The same goes for freeing the per_cpu data of the per_cpu
* ops.
*/
if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
/*
* We need to do a hard force of sched synchronization.
* This is because we use preempt_disable() to do RCU, but
* the function tracers can be called where RCU is not watching
* (like before user_exit()). We can not rely on the RCU
* infrastructure to do the synchronization, thus we must do it
* ourselves.
*/
schedule_on_each_cpu(ftrace_sync);
/*
* When the kernel is preeptive, tasks can be preempted
* while on a ftrace trampoline. Just scheduling a task on
* a CPU is not good enough to flush them. Calling
* synchornize_rcu_tasks() will wait for those tasks to
* execute and either schedule voluntarily or enter user space.
*/
if (IS_ENABLED(CONFIG_PREEMPTION))
synchronize_rcu_tasks();
free_ops:
arch_ftrace_trampoline_free(ops);
}
return 0;
}
static void ftrace_startup_sysctl(void)
{
int command;
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_UPDATE_CALLS;
if (ftrace_graph_active)
command |= FTRACE_START_FUNC_RET;
ftrace_startup_enable(command);
}
}
static void ftrace_shutdown_sysctl(void)
{
int command;
if (unlikely(ftrace_disabled))
return;
/* ftrace_start_up is true if ftrace is running */
if (ftrace_start_up) {
command = FTRACE_DISABLE_CALLS;
if (ftrace_graph_active)
command |= FTRACE_STOP_FUNC_RET;
ftrace_run_update_code(command);
}
}
static u64 ftrace_update_time;
unsigned long ftrace_update_tot_cnt;
unsigned long ftrace_number_of_pages;
unsigned long ftrace_number_of_groups;
static inline int ops_traces_mod(struct ftrace_ops *ops)
{
/*
* Filter_hash being empty will default to trace module.
* But notrace hash requires a test of individual module functions.
*/
return ftrace_hash_empty(ops->func_hash->filter_hash) &&
ftrace_hash_empty(ops->func_hash->notrace_hash);
}
/*
* Check if the current ops references the record.
*
* If the ops traces all functions, then it was already accounted for.
* If the ops does not trace the current record function, skip it.
* If the ops ignores the function via notrace filter, skip it.
*/
static inline bool
ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
{
/* If ops isn't enabled, ignore it */
if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
return false;
/* If ops traces all then it includes this function */
if (ops_traces_mod(ops))
return true;
/* The function must be in the filter */
if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
!__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
return false;
/* If in notrace hash, we ignore it too */
if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
return false;
return true;
}
static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
{
struct ftrace_page *pg;
struct dyn_ftrace *p;
u64 start, stop;
unsigned long update_cnt = 0;
unsigned long rec_flags = 0;
int i;
start = ftrace_now(raw_smp_processor_id());
/*
* When a module is loaded, this function is called to convert
* the calls to mcount in its text to nops, and also to create
* an entry in the ftrace data. Now, if ftrace is activated
* after this call, but before the module sets its text to
* read-only, the modification of enabling ftrace can fail if
* the read-only is done while ftrace is converting the calls.
* To prevent this, the module's records are set as disabled
* and will be enabled after the call to set the module's text
* to read-only.
*/
if (mod)
rec_flags |= FTRACE_FL_DISABLED;
for (pg = new_pgs; pg; pg = pg->next) {
for (i = 0; i < pg->index; i++) {
/* If something went wrong, bail without enabling anything */
if (unlikely(ftrace_disabled))
return -1;
p = &pg->records[i];
p->flags = rec_flags;
/*
* Do the initial record conversion from mcount jump
* to the NOP instructions.
*/
if (!__is_defined(CC_USING_NOP_MCOUNT) &&
!ftrace_nop_initialize(mod, p))
break;
update_cnt++;
}
}
stop = ftrace_now(raw_smp_processor_id());
ftrace_update_time = stop - start;
ftrace_update_tot_cnt += update_cnt;
return 0;
}
static int ftrace_allocate_records(struct ftrace_page *pg, int count)
{
int order;
int cnt;
if (WARN_ON(!count))
return -EINVAL;
order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
/*
* We want to fill as much as possible. No more than a page
* may be empty.
*/
while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
order--;
again:
pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
if (!pg->records) {
/* if we can't allocate this size, try something smaller */
if (!order)
return -ENOMEM;
order >>= 1;
goto again;
}
ftrace_number_of_pages += 1 << order;
ftrace_number_of_groups++;
cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
pg->size = cnt;
if (cnt > count)
cnt = count;
return cnt;
}
static struct ftrace_page *
ftrace_allocate_pages(unsigned long num_to_init)
{
struct ftrace_page *start_pg;
struct ftrace_page *pg;
int order;
int cnt;
if (!num_to_init)
return NULL;
start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
if (!pg)
return NULL;
/*
* Try to allocate as much as possible in one continues
* location that fills in all of the space. We want to
* waste as little space as possible.
*/
for (;;) {
cnt = ftrace_allocate_records(pg, num_to_init);
if (cnt < 0)
goto free_pages;
num_to_init -= cnt;
if (!num_to_init)
break;
pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
if (!pg->next)
goto free_pages;
pg = pg->next;
}
return start_pg;
free_pages:
pg = start_pg;
while (pg) {
order = get_count_order(pg->size / ENTRIES_PER_PAGE);
free_pages((unsigned long)pg->records, order);
start_pg = pg->next;
kfree(pg);
pg = start_pg;
ftrace_number_of_pages -= 1 << order;
ftrace_number_of_groups--;
}
pr_info("ftrace: FAILED to allocate memory for functions\n");
return NULL;
}
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
struct ftrace_iterator {
loff_t pos;
loff_t func_pos;
loff_t mod_pos;
struct ftrace_page *pg;
struct dyn_ftrace *func;
struct ftrace_func_probe *probe;
struct ftrace_func_entry *probe_entry;
struct trace_parser parser;
struct ftrace_hash *hash;
struct ftrace_ops *ops;
struct trace_array *tr;
struct list_head *mod_list;
int pidx;
int idx;
unsigned flags;
};
static void *
t_probe_next(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
struct trace_array *tr = iter->ops->private;
struct list_head *func_probes;
struct ftrace_hash *hash;
struct list_head *next;
struct hlist_node *hnd = NULL;
struct hlist_head *hhd;
int size;
(*pos)++;
iter->pos = *pos;
if (!tr)
return NULL;
func_probes = &tr->func_probes;
if (list_empty(func_probes))
return NULL;
if (!iter->probe) {
next = func_probes->next;
iter->probe = list_entry(next, struct ftrace_func_probe, list);
}
if (iter->probe_entry)
hnd = &iter->probe_entry->hlist;
hash = iter->probe->ops.func_hash->filter_hash;
/*
* A probe being registered may temporarily have an empty hash
* and it's at the end of the func_probes list.
*/
if (!hash || hash == EMPTY_HASH)
return NULL;
size = 1 << hash->size_bits;
retry:
if (iter->pidx >= size) {
if (iter->probe->list.next == func_probes)
return NULL;
next = iter->probe->list.next;
iter->probe = list_entry(next, struct ftrace_func_probe, list);
hash = iter->probe->ops.func_hash->filter_hash;
size = 1 << hash->size_bits;
iter->pidx = 0;
}
hhd = &hash->buckets[iter->pidx];
if (hlist_empty(hhd)) {
iter->pidx++;
hnd = NULL;
goto retry;
}
if (!hnd)
hnd = hhd->first;
else {
hnd = hnd->next;
if (!hnd) {
iter->pidx++;
goto retry;
}
}
if (WARN_ON_ONCE(!hnd))
return NULL;
iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
return iter;
}
static void *t_probe_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_DO_PROBES))
return NULL;
if (iter->mod_pos > *pos)
return NULL;
iter->probe = NULL;
iter->probe_entry = NULL;
iter->pidx = 0;
for (l = 0; l <= (*pos - iter->mod_pos); ) {
p = t_probe_next(m, &l);
if (!p)
break;
}
if (!p)
return NULL;
/* Only set this if we have an item */
iter->flags |= FTRACE_ITER_PROBE;
return iter;
}
static int
t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
{
struct ftrace_func_entry *probe_entry;
struct ftrace_probe_ops *probe_ops;
struct ftrace_func_probe *probe;
probe = iter->probe;
probe_entry = iter->probe_entry;
if (WARN_ON_ONCE(!probe || !probe_entry))
return -EIO;
probe_ops = probe->probe_ops;
if (probe_ops->print)
return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
(void *)probe_ops->func);
return 0;
}
static void *
t_mod_next(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
struct trace_array *tr = iter->tr;
(*pos)++;
iter->pos = *pos;
iter->mod_list = iter->mod_list->next;
if (iter->mod_list == &tr->mod_trace ||
iter->mod_list == &tr->mod_notrace) {
iter->flags &= ~FTRACE_ITER_MOD;
return NULL;
}
iter->mod_pos = *pos;
return iter;
}
static void *t_mod_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->mod_pos = iter->func_pos;
/* probes are only available if tr is set */
if (!iter->tr)
return NULL;
for (l = 0; l <= (*pos - iter->func_pos); ) {
p = t_mod_next(m, &l);
if (!p)
break;
}
if (!p) {
iter->flags &= ~FTRACE_ITER_MOD;
return t_probe_start(m, pos);
}
/* Only set this if we have an item */
iter->flags |= FTRACE_ITER_MOD;
return iter;
}
static int
t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
{
struct ftrace_mod_load *ftrace_mod;
struct trace_array *tr = iter->tr;
if (WARN_ON_ONCE(!iter->mod_list) ||
iter->mod_list == &tr->mod_trace ||
iter->mod_list == &tr->mod_notrace)
return -EIO;
ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
if (ftrace_mod->func)
seq_printf(m, "%s", ftrace_mod->func);
else
seq_putc(m, '*');
seq_printf(m, ":mod:%s\n", ftrace_mod->module);
return 0;
}
static void *
t_func_next(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
struct dyn_ftrace *rec = NULL;
(*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 (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
!ftrace_lookup_ip(iter->hash, rec->ip)) ||
((iter->flags & FTRACE_ITER_ENABLED) &&
!(rec->flags & FTRACE_FL_ENABLED))) {
rec = NULL;
goto retry;
}
}
if (!rec)
return NULL;
iter->pos = iter->func_pos = *pos;
iter->func = rec;
return iter;
}
static void *
t_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
loff_t l = *pos; /* t_probe_start() must use original pos */
void *ret;
if (unlikely(ftrace_disabled))
return NULL;
if (iter->flags & FTRACE_ITER_PROBE)
return t_probe_next(m, pos);
if (iter->flags & FTRACE_ITER_MOD)
return t_mod_next(m, pos);
if (iter->flags & FTRACE_ITER_PRINTALL) {
/* next must increment pos, and t_probe_start does not */
(*pos)++;
return t_mod_start(m, &l);
}
ret = t_func_next(m, pos);
if (!ret)
return t_mod_start(m, &l);
return ret;
}
static void reset_iter_read(struct ftrace_iterator *iter)
{
iter->pos = 0;
iter->func_pos = 0;
iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
}
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);
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 | FTRACE_ITER_NOTRACE)) &&
ftrace_hash_empty(iter->hash)) {
iter->func_pos = 1; /* Account for the message */
if (*pos > 0)
return t_mod_start(m, pos);
iter->flags |= FTRACE_ITER_PRINTALL;
/* reset in case of seek/pread */
iter->flags &= ~FTRACE_ITER_PROBE;
return iter;
}
if (iter->flags & FTRACE_ITER_MOD)
return t_mod_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_func_next(m, &l);
if (!p)
break;
}
if (!p)
return t_mod_start(m, pos);
return iter;
}
static void t_stop(struct seq_file *m, void *p)
{
mutex_unlock(&ftrace_lock);
}
void * __weak
arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
{
return NULL;
}
static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
struct dyn_ftrace *rec)
{
void *ptr;
ptr = arch_ftrace_trampoline_func(ops, rec);
if (ptr)
seq_printf(m, " ->%pS", ptr);
}
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_PROBE)
return t_probe_show(m, iter);
if (iter->flags & FTRACE_ITER_MOD)
return t_mod_show(m, iter);
if (iter->flags & FTRACE_ITER_PRINTALL) {
if (iter->flags & FTRACE_ITER_NOTRACE)
seq_puts(m, "#### no functions disabled ####\n");
else
seq_puts(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) {
struct ftrace_ops *ops;
seq_printf(m, " (%ld)%s%s%s",
ftrace_rec_count(rec),
rec->flags & FTRACE_FL_REGS ? " R" : " ",
rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ",
rec->flags & FTRACE_FL_DIRECT ? " D" : " ");
if (rec->flags & FTRACE_FL_TRAMP_EN) {
ops = ftrace_find_tramp_ops_any(rec);
if (ops) {
do {
seq_printf(m, "\ttramp: %pS (%pS)",
(void *)ops->trampoline,
(void *)ops->func);
add_trampoline_func(m, ops, rec);
ops = ftrace_find_tramp_ops_next(rec, ops);
} while (ops);
} else
seq_puts(m, "\ttramp: ERROR!");
} else {
add_trampoline_func(m, NULL, rec);
}
if (rec->flags & FTRACE_FL_DIRECT) {
unsigned long direct;
direct = ftrace_find_rec_direct(rec->ip);
if (direct)
seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
}
}
seq_putc(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;
ret = security_locked_down(LOCKDOWN_TRACEFS);
if (ret)
return ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
if (!iter)
return -ENOMEM;
iter->pg = ftrace_pages_start;
iter->ops = &global_ops;
return 0;
}
static int
ftrace_enabled_open(struct inode *inode, struct file *file)
{
struct ftrace_iterator *iter;
/*
* This shows us what functions are currently being
* traced and by what. Not sure if we want lockdown
* to hide such critical information for an admin.
* Although, perhaps it can show information we don't
* want people to see, but if something is tracing
* something, we probably want to know about it.
*/
iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
if (!iter)
return -ENOMEM;
iter->pg = ftrace_pages_start;
iter->flags = FTRACE_ITER_ENABLED;
iter->ops = &global_ops;
return 0;
}
/**
* ftrace_regex_open - initialize function tracer filter files
* @ops: The ftrace_ops that hold the hash filters
* @flag: The type of filter to process
* @inode: The inode, usually passed in to your open routine
* @file: The file, usually passed in to your open routine
*
* ftrace_regex_open() initializes the filter files for the
* @ops. Depending on @flag it may process the filter hash or
* the notrace hash of @ops. With this called from the open
* routine, you can use ftrace_filter_write() for the write
* routine if @flag has FTRACE_ITER_FILTER set, or
* ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
* tracing_lseek() should be used as the lseek routine, and
* release must call ftrace_regex_release().
*/
int
ftrace_regex_open(struct ftrace_ops *ops, int flag,
struct inode *inode, struct file *file)
{
struct ftrace_iterator *iter;
struct ftrace_hash *hash;
struct list_head *mod_head;
struct trace_array *tr = ops->private;
int ret = -ENOMEM;
ftrace_ops_init(ops);
if (unlikely(ftrace_disabled))
return -ENODEV;
if (tracing_check_open_get_tr(tr))
return -ENODEV;
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
goto out;
if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
goto out;
iter->ops = ops;
iter->flags = flag;
iter->tr = tr;
mutex_lock(&ops->func_hash->regex_lock);
if (flag & FTRACE_ITER_NOTRACE) {
hash = ops->func_hash->notrace_hash;
mod_head = tr ? &tr->mod_notrace : NULL;
} else {
hash = ops->func_hash->filter_hash;
mod_head = tr ? &tr->mod_trace : NULL;
}
iter->mod_list = mod_head;
if (file->f_mode & FMODE_WRITE) {
const int size_bits = FTRACE_HASH_DEFAULT_BITS;
if (file->f_flags & O_TRUNC) {
iter->hash = alloc_ftrace_hash(size_bits);
clear_ftrace_mod_list(mod_head);
} else {
iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
}
if (!iter->hash) {
trace_parser_put(&iter->parser);
goto out_unlock;
}
} else
iter->hash = hash;
ret = 0;
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);
}
} else
file->private_data = iter;
out_unlock:
mutex_unlock(&ops->func_hash->regex_lock);
out:
if (ret) {
kfree(iter);
if (tr)
trace_array_put(tr);
}
return ret;
}
static int
ftrace_filter_open(struct inode *inode, struct file *file)
{
struct ftrace_ops *ops = inode->i_private;
/* Checks for tracefs lockdown */
return ftrace_regex_open(ops,
FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
inode, file);
}
static int
ftrace_notrace_open(struct inode *inode, struct file *file)
{
struct ftrace_ops *ops = inode->i_private;
/* Checks for tracefs lockdown */
return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
inode, file);
}
/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
struct ftrace_glob {
char *search;
unsigned len;
int type;
};
/*
* If symbols in an architecture don't correspond exactly to the user-visible
* name of what they represent, it is possible to define this function to
* perform the necessary adjustments.
*/
char * __weak arch_ftrace_match_adjust(char *str, const char *search)
{
return str;
}
static int ftrace_match(char *str, struct ftrace_glob *g)
{
int matched = 0;
int slen;
str = arch_ftrace_match_adjust(str, g->search);
switch (g->type) {
case MATCH_FULL:
if (strcmp(str, g->search) == 0)
matched = 1;
break;
case MATCH_FRONT_ONLY:
if (strncmp(str, g->search, g->len) == 0)
matched = 1;
break;
case MATCH_MIDDLE_ONLY:
if (strstr(str, g->search))
matched = 1;
break;
case MATCH_END_ONLY:
slen = strlen(str);
if (slen >= g->len &&
memcmp(str + slen - g->len, g->search, g->len) == 0)
matched = 1;
break;
case MATCH_GLOB:
if (glob_match(g->search, str))
matched = 1;
break;
}
return matched;
}
static int
enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
{
struct ftrace_func_entry *entry;
int ret = 0;
entry = ftrace_lookup_ip(hash, rec->ip);
if (clear_filter) {
/* 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
add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
int clear_filter)
{
long index = simple_strtoul(func_g->search, NULL, 0);
struct ftrace_page *pg;
struct dyn_ftrace *rec;
/* The index starts at 1 */
if (--index < 0)
return 0;
do_for_each_ftrace_rec(pg, rec) {
if (pg->index <= index) {
index -= pg->index;
/* this is a double loop, break goes to the next page */
break;
}
rec = &pg->records[index];
enter_record(hash, rec, clear_filter);
return 1;
} while_for_each_ftrace_rec();
return 0;
}
static int
ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
struct ftrace_glob *mod_g, int exclude_mod)
{
char str[KSYM_SYMBOL_LEN];
char *modname;
kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
if (mod_g) {
int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
/* blank module name to match all modules */
if (!mod_g->len) {
/* blank module globbing: modname xor exclude_mod */
if (!exclude_mod != !modname)
goto func_match;
return 0;
}
/*
* exclude_mod is set to trace everything but the given
* module. If it is set and the module matches, then
* return 0. If it is not set, and the module doesn't match
* also return 0. Otherwise, check the function to see if
* that matches.
*/
if (!mod_matches == !exclude_mod)
return 0;
func_match:
/* blank search means to match all funcs in the mod */
if (!func_g->len)
return 1;
}
return ftrace_match(str, func_g);
}
static int
match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
{
struct ftrace_page *pg;
struct dyn_ftrace *rec;
struct ftrace_glob func_g = { .type = MATCH_FULL };
struct ftrace_glob mod_g = { .type = MATCH_FULL };
struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
int exclude_mod = 0;
int found = 0;
int ret;
int clear_filter = 0;
if (func) {
func_g.type = filter_parse_regex(func, len, &func_g.search,
&clear_filter);
func_g.len = strlen(func_g.search);
}
if (mod) {
mod_g.type = filter_parse_regex(mod, strlen(mod),
&mod_g.search, &exclude_mod);
mod_g.len = strlen(mod_g.search);
}
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled))
goto out_unlock;
if (func_g.type == MATCH_INDEX) {
found = add_rec_by_index(hash, &func_g, clear_filter);
goto out_unlock;
}
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_DISABLED)
continue;
if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
ret = enter_record(hash, rec, clear_filter);
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);
}
static void ftrace_ops_update_code(struct ftrace_ops *ops,
struct ftrace_ops_hash *old_hash)
{
struct ftrace_ops *op;
if (!ftrace_enabled)
return;
if (ops->flags & FTRACE_OPS_FL_ENABLED) {
ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
return;
}
/*
* If this is the shared global_ops filter, then we need to
* check if there is another ops that shares it, is enabled.
* If so, we still need to run the modify code.
*/
if (ops->func_hash != &global_ops.local_hash)
return;
do_for_each_ftrace_op(op, ftrace_ops_list) {
if (op->func_hash == &global_ops.local_hash &&
op->flags & FTRACE_OPS_FL_ENABLED) {
ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
/* Only need to do this once */
return;
}
} while_for_each_ftrace_op(op);
}
static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
struct ftrace_hash **orig_hash,
struct ftrace_hash *hash,
int enable)
{
struct ftrace_ops_hash old_hash_ops;
struct ftrace_hash *old_hash;
int ret;
old_hash = *orig_hash;
old_hash_ops.filter_hash = ops->func_hash->filter_hash;
old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
ret = ftrace_hash_move(ops, enable, orig_hash, hash);
if (!ret) {
ftrace_ops_update_code(ops, &old_hash_ops);
free_ftrace_hash_rcu(old_hash);
}
return ret;
}
static bool module_exists(const char *module)
{
/* All modules have the symbol __this_module */
static const char this_mod[] = "__this_module";
char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
unsigned long val;
int n;
n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
if (n > sizeof(modname) - 1)
return false;
val = module_kallsyms_lookup_name(modname);
return val != 0;
}
static int cache_mod(struct trace_array *tr,
const char *func, char *module, int enable)
{
struct ftrace_mod_load *ftrace_mod, *n;
struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
int ret;
mutex_lock(&ftrace_lock);
/* We do not cache inverse filters */
if (func[0] == '!') {
func++;
ret = -EINVAL;
/* Look to remove this hash */
list_for_each_entry_safe(ftrace_mod, n, head, list) {
if (strcmp(ftrace_mod->module, module) != 0)
continue;
/* no func matches all */
if (strcmp(func, "*") == 0 ||
(ftrace_mod->func &&
strcmp(ftrace_mod->func, func) == 0)) {
ret = 0;
free_ftrace_mod(ftrace_mod);
continue;
}
}
goto out;
}
ret = -EINVAL;
/* We only care about modules that have not been loaded yet */
if (module_exists(module))
goto out;
/* Save this string off, and execute it when the module is loaded */
ret = ftrace_add_mod(tr, func, module, enable);
out:
mutex_unlock(&ftrace_lock);
return ret;
}
static int
ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
int reset, int enable);
#ifdef CONFIG_MODULES
static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
char *mod, bool enable)
{
struct ftrace_mod_load *ftrace_mod, *n;
struct ftrace_hash **orig_hash, *new_hash;
LIST_HEAD(process_mods);
char *func;
int ret;
mutex_lock(&ops->func_hash->regex_lock);
if (enable)
orig_hash = &ops->func_hash->filter_hash;
else
orig_hash = &ops->func_hash->notrace_hash;
new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
*orig_hash);
if (!new_hash)
goto out; /* warn? */
mutex_lock(&ftrace_lock);
list_for_each_entry_safe(ftrace_mod, n, head, list) {
if (strcmp(ftrace_mod->module, mod) != 0)
continue;
if (ftrace_mod->func)
func = kstrdup(ftrace_mod->func, GFP_KERNEL);
else
func = kstrdup("*", GFP_KERNEL);
if (!func) /* warn? */
continue;
list_del(&ftrace_mod->list);
list_add(&ftrace_mod->list, &process_mods);
/* Use the newly allocated func, as it may be "*" */
kfree(ftrace_mod->func);
ftrace_mod->func = func;
}
mutex_unlock(&ftrace_lock);
list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
func = ftrace_mod->func;
/* Grabs ftrace_lock, which is why we have this extra step */
match_records(new_hash, func, strlen(func), mod);
free_ftrace_mod(ftrace_mod);
}
if (enable && list_empty(head))
new_hash->flags &= ~FTRACE_HASH_FL_MOD;
mutex_lock(&ftrace_lock);
ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
new_hash, enable);
mutex_unlock(&ftrace_lock);
out:
mutex_unlock(&ops->func_hash->regex_lock);
free_ftrace_hash(new_hash);
}
static void process_cached_mods(const char *mod_name)
{
struct trace_array *tr;
char *mod;
mod = kstrdup(mod_name, GFP_KERNEL);
if (!mod)
return;
mutex_lock(&trace_types_lock);
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
if (!list_empty(&tr->mod_trace))
process_mod_list(&tr->mod_trace, tr->ops, mod, true);
if (!list_empty(&tr->mod_notrace))
process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
}
mutex_unlock(&trace_types_lock);
kfree(mod);
}
#endif
/*
* 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 trace_array *tr, struct ftrace_hash *hash,
char *func_orig, char *cmd, char *module, int enable)
{
char *func;
int ret;
/* match_records() modifies func, and we need the original */
func = kstrdup(func_orig, GFP_KERNEL);
if (!func)
return -ENOMEM;
/*
* 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.
*/
ret = match_records(hash, func, strlen(func), module);
kfree(func);
if (!ret)
return cache_mod(tr, func_orig, module, enable);
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);
}
core_initcall(ftrace_mod_cmd_init);
static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs)
{
struct ftrace_probe_ops *probe_ops;
struct ftrace_func_probe *probe;
probe = container_of(op, struct ftrace_func_probe, ops);
probe_ops = probe->probe_ops;
/*
* 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();
probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
preempt_enable_notrace();
}
struct ftrace_func_map {
struct ftrace_func_entry entry;
void *data;
};
struct ftrace_func_mapper {
struct ftrace_hash hash;
};
/**
* allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
*
* Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
*/
struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
{
struct ftrace_hash *hash;
/*
* The mapper is simply a ftrace_hash, but since the entries
* in the hash are not ftrace_func_entry type, we define it
* as a separate structure.
*/
hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
return (struct ftrace_func_mapper *)hash;
}
/**
* ftrace_func_mapper_find_ip - Find some data mapped to an ip
* @mapper: The mapper that has the ip maps
* @ip: the instruction pointer to find the data for
*
* Returns the data mapped to @ip if found otherwise NULL. The return
* is actually the address of the mapper data pointer. The address is
* returned for use cases where the data is no bigger than a long, and
* the user can use the data pointer as its data instead of having to
* allocate more memory for the reference.
*/
void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
unsigned long ip)
{
struct ftrace_func_entry *entry;
struct ftrace_func_map *map;
entry = ftrace_lookup_ip(&mapper->hash, ip);
if (!entry)
return NULL;
map = (struct ftrace_func_map *)entry;
return &map->data;
}
/**
* ftrace_func_mapper_add_ip - Map some data to an ip
* @mapper: The mapper that has the ip maps
* @ip: The instruction pointer address to map @data to
* @data: The data to map to @ip
*
* Returns 0 on succes otherwise an error.
*/
int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
unsigned long ip, void *data)
{
struct ftrace_func_entry *entry;
struct ftrace_func_map *map;
entry = ftrace_lookup_ip(&mapper->hash, ip);
if (entry)
return -EBUSY;
map = kmalloc(sizeof(*map), GFP_KERNEL);
if (!map)
return -ENOMEM;
map->entry.ip = ip;
map->data = data;
__add_hash_entry(&mapper->hash, &map->entry);
return 0;
}
/**
* ftrace_func_mapper_remove_ip - Remove an ip from the mapping
* @mapper: The mapper that has the ip maps
* @ip: The instruction pointer address to remove the data from
*
* Returns the data if it is found, otherwise NULL.
* Note, if the data pointer is used as the data itself, (see
* ftrace_func_mapper_find_ip(), then the return value may be meaningless,
* if the data pointer was set to zero.
*/
void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
unsigned long ip)
{
struct ftrace_func_entry *entry;
struct ftrace_func_map *map;
void *data;
entry = ftrace_lookup_ip(&mapper->hash, ip);
if (!entry)
return NULL;
map = (struct ftrace_func_map *)entry;
data = map->data;
remove_hash_entry(&mapper->hash, entry);
kfree(entry);
return data;
}
/**
* free_ftrace_func_mapper - free a mapping of ips and data
* @mapper: The mapper that has the ip maps
* @free_func: A function to be called on each data item.
*
* This is used to free the function mapper. The @free_func is optional
* and can be used if the data needs to be freed as well.
*/
void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
ftrace_mapper_func free_func)
{
struct ftrace_func_entry *entry;
struct ftrace_func_map *map;
struct hlist_head *hhd;
int size, i;
if (!mapper)
return;
if (free_func && mapper->hash.count) {
size = 1 << mapper->hash.size_bits;
for (i = 0; i < size; i++) {
hhd = &mapper->hash.buckets[i];
hlist_for_each_entry(entry, hhd, hlist) {
map = (struct ftrace_func_map *)entry;
free_func(map);
}
}
}
free_ftrace_hash(&mapper->hash);
}
static void release_probe(struct ftrace_func_probe *probe)
{
struct ftrace_probe_ops *probe_ops;
mutex_lock(&ftrace_lock);
WARN_ON(probe->ref <= 0);
/* Subtract the ref that was used to protect this instance */
probe->ref--;
if (!probe->ref) {
probe_ops = probe->probe_ops;
/*
* Sending zero as ip tells probe_ops to free
* the probe->data itself
*/
if (probe_ops->free)
probe_ops->free(probe_ops, probe->tr, 0, probe->data);
list_del(&probe->list);
kfree(probe);
}
mutex_unlock(&ftrace_lock);
}
static void acquire_probe_locked(struct ftrace_func_probe *probe)
{
/*
* Add one ref to keep it from being freed when releasing the
* ftrace_lock mutex.
*/
probe->ref++;
}
int
register_ftrace_function_probe(char *glob, struct trace_array *tr,
struct ftrace_probe_ops *probe_ops,
void *data)
{
struct ftrace_func_entry *entry;
struct ftrace_func_probe *probe;
struct ftrace_hash **orig_hash;
struct ftrace_hash *old_hash;
struct ftrace_hash *hash;
int count = 0;
int size;
int ret;
int i;
if (WARN_ON(!tr))
return -EINVAL;
/* We do not support '!' for function probes */
if (WARN_ON(glob[0] == '!'))
return -EINVAL;
mutex_lock(&ftrace_lock);
/* Check if the probe_ops is already registered */
list_for_each_entry(probe, &tr->func_probes, list) {
if (probe->probe_ops == probe_ops)
break;
}
if (&probe->list == &tr->func_probes) {
probe = kzalloc(sizeof(*probe), GFP_KERNEL);
if (!probe) {
mutex_unlock(&ftrace_lock);
return -ENOMEM;
}
probe->probe_ops = probe_ops;
probe->ops.func = function_trace_probe_call;
probe->tr = tr;
ftrace_ops_init(&probe->ops);
list_add(&probe->list, &tr->func_probes);
}
acquire_probe_locked(probe);
mutex_unlock(&ftrace_lock);
/*
* Note, there's a small window here that the func_hash->filter_hash
* may be NULL or empty. Need to be carefule when reading the loop.
*/
mutex_lock(&probe->ops.func_hash->regex_lock);
orig_hash = &probe->ops.func_hash->filter_hash;
old_hash = *orig_hash;
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
if (!hash) {
ret = -ENOMEM;
goto out;
}
ret = ftrace_match_records(hash, glob, strlen(glob));
/* Nothing found? */
if (!ret)
ret = -EINVAL;
if (ret < 0)
goto out;
size = 1 << hash->size_bits;
for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
if (ftrace_lookup_ip(old_hash, entry->ip))
continue;
/*
* 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 (probe_ops->init) {
ret = probe_ops->init(probe_ops, tr,
entry->ip, data,
&probe->data);
if (ret < 0) {
if (probe_ops->free && count)
probe_ops->free(probe_ops, tr,
0, probe->data);
probe->data = NULL;
goto out;
}
}
count++;
}
}
mutex_lock(&ftrace_lock);
if (!count) {
/* Nothing was added? */
ret = -EINVAL;
goto out_unlock;
}
ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
hash, 1);
if (ret < 0)
goto err_unlock;
/* One ref for each new function traced */
probe->ref += count;
if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
ret = ftrace_startup(&probe->ops, 0);
out_unlock:
mutex_unlock(&ftrace_lock);
if (!ret)
ret = count;
out:
mutex_unlock(&probe->ops.func_hash->regex_lock);
free_ftrace_hash(hash);
release_probe(probe);
return ret;
err_unlock:
if (!probe_ops->free || !count)
goto out_unlock;
/* Failed to do the move, need to call the free functions */
for (i = 0; i < size; i++) {
hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
if (ftrace_lookup_ip(old_hash, entry->ip))
continue;
probe_ops->free(probe_ops, tr, entry->ip, probe->data);
}
}
goto out_unlock;
}
int
unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
struct ftrace_probe_ops *probe_ops)
{
struct ftrace_ops_hash old_hash_ops;
struct ftrace_func_entry *entry;
struct ftrace_func_probe *probe;
struct ftrace_glob func_g;
struct ftrace_hash **orig_hash;
struct ftrace_hash *old_hash;
struct ftrace_hash *hash = NULL;
struct hlist_node *tmp;
struct hlist_head hhd;
char str[KSYM_SYMBOL_LEN];
int count = 0;
int i, ret = -ENODEV;
int size;
if (!glob || !strlen(glob) || !strcmp(glob, "*"))
func_g.search = NULL;
else {
int not;
func_g.type = filter_parse_regex(glob, strlen(glob),
&func_g.search, &not);
func_g.len = strlen(func_g.search);
/* we do not support '!' for function probes */
if (WARN_ON(not))
return -EINVAL;
}
mutex_lock(&ftrace_lock);
/* Check if the probe_ops is already registered */
list_for_each_entry(probe, &tr->func_probes, list) {
if (probe->probe_ops == probe_ops)
break;
}
if (&probe->list == &tr->func_probes)
goto err_unlock_ftrace;
ret = -EINVAL;
if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
goto err_unlock_ftrace;
acquire_probe_locked(probe);
mutex_unlock(&ftrace_lock);
mutex_lock(&probe->ops.func_hash->regex_lock);
orig_hash = &probe->ops.func_hash->filter_hash;
old_hash = *orig_hash;
if (ftrace_hash_empty(old_hash))
goto out_unlock;
old_hash_ops.filter_hash = old_hash;
/* Probes only have filters */
old_hash_ops.notrace_hash = NULL;
ret = -ENOMEM;
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
if (!hash)
goto out_unlock;
INIT_HLIST_HEAD(&hhd);
size = 1 << hash->size_bits;
for (i = 0; i < size; i++) {
hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
if (func_g.search) {
kallsyms_lookup(entry->ip, NULL, NULL,
NULL, str);
if (!ftrace_match(str, &func_g))
continue;
}
count++;
remove_hash_entry(hash, entry);
hlist_add_head(&entry->hlist, &hhd);
}
}
/* Nothing found? */
if (!count) {
ret = -EINVAL;
goto out_unlock;
}
mutex_lock(&ftrace_lock);
WARN_ON(probe->ref < count);
probe->ref -= count;
if (ftrace_hash_empty(hash))
ftrace_shutdown(&probe->ops, 0);
ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
hash, 1);
/* still need to update the function call sites */
if (ftrace_enabled && !ftrace_hash_empty(hash))
ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
&old_hash_ops);
synchronize_rcu();
hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
hlist_del(&entry->hlist);
if (probe_ops->free)
probe_ops->free(probe_ops, tr, entry->ip, probe->data);
kfree(entry);
}
mutex_unlock(&ftrace_lock);
out_unlock:
mutex_unlock(&probe->ops.func_hash->regex_lock);
free_ftrace_hash(hash);
release_probe(probe);
return ret;
err_unlock_ftrace:
mutex_unlock(&ftrace_lock);
return ret;
}
void clear_ftrace_function_probes(struct trace_array *tr)
{
struct ftrace_func_probe *probe, *n;
list_for_each_entry_safe(probe, n, &tr->func_probes, list)
unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
}
static LIST_HEAD(ftrace_commands);
static DEFINE_MUTEX(ftrace_cmd_mutex);
/*
* Currently we only register ftrace commands from __init, so mark this
* __init too.
*/
__init 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;
}
/*
* Currently we only unregister ftrace commands from __init, so mark
* this __init too.
*/
__init 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_iterator *iter,
char *buff, int len, int enable)
{
struct ftrace_hash *hash = iter->hash;
struct trace_array *tr = iter->ops->private;
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(tr, 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;
if (file->f_mode & FMODE_READ) {
struct seq_file *m = file->private_data;
iter = m->private;
} else
iter = file->private_data;
if (unlikely(ftrace_disabled))
return -ENODEV;
/* iter->hash is a local copy, so we don't need regex_lock */
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, parser->buffer,
parser->idx, enable);
trace_parser_clear(parser);
if (ret < 0)
goto out;
}
ret = read;
out:
return ret;
}
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);
}
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_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
{
struct ftrace_func_entry *entry;
if (!ftrace_location(ip))
return -EINVAL;
if (remove) {
entry = ftrace_lookup_ip(hash, ip);
if (!entry)
return -ENOENT;
free_hash_entry(hash, entry);
return 0;
}
return add_hash_entry(hash, ip);
}
static int
ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
unsigned long ip, int remove, int reset, int enable)
{
struct ftrace_hash **orig_hash;
struct ftrace_hash *hash;
int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
mutex_lock(&ops->func_hash->regex_lock);
if (enable)
orig_hash = &ops->func_hash->filter_hash;
else
orig_hash = &ops->func_hash->notrace_hash;
if (reset)
hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
else
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
if (!hash) {
ret = -ENOMEM;
goto out_regex_unlock;
}
if (buf && !ftrace_match_records(hash, buf, len)) {
ret = -EINVAL;
goto out_regex_unlock;
}
if (ip) {
ret = ftrace_match_addr(hash, ip, remove);
if (ret < 0)
goto out_regex_unlock;
}
mutex_lock(&ftrace_lock);
ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
mutex_unlock(&ftrace_lock);
out_regex_unlock:
mutex_unlock(&ops->func_hash->regex_lock);
free_ftrace_hash(hash);
return ret;
}
static int
ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
int reset, int enable)
{
return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
}
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
struct ftrace_direct_func {
struct list_head next;
unsigned long addr;
int count;
};
static LIST_HEAD(ftrace_direct_funcs);
/**
* ftrace_find_direct_func - test an address if it is a registered direct caller
* @addr: The address of a registered direct caller
*
* This searches to see if a ftrace direct caller has been registered
* at a specific address, and if so, it returns a descriptor for it.
*
* This can be used by architecture code to see if an address is
* a direct caller (trampoline) attached to a fentry/mcount location.
* This is useful for the function_graph tracer, as it may need to
* do adjustments if it traced a location that also has a direct
* trampoline attached to it.
*/
struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
{
struct ftrace_direct_func *entry;
bool found = false;
/* May be called by fgraph trampoline (protected by rcu tasks) */
list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
if (entry->addr == addr) {
found = true;
break;
}
}
if (found)
return entry;
return NULL;
}
/**
* register_ftrace_direct - Call a custom trampoline directly
* @ip: The address of the nop at the beginning of a function
* @addr: The address of the trampoline to call at @ip
*
* This is used to connect a direct call from the nop location (@ip)
* at the start of ftrace traced functions. The location that it calls
* (@addr) must be able to handle a direct call, and save the parameters
* of the function being traced, and restore them (or inject new ones
* if needed), before returning.
*
* Returns:
* 0 on success
* -EBUSY - Another direct function is already attached (there can be only one)
* -ENODEV - @ip does not point to a ftrace nop location (or not supported)
* -ENOMEM - There was an allocation failure.
*/
int register_ftrace_direct(unsigned long ip, unsigned long addr)
{
struct ftrace_direct_func *direct;
struct ftrace_func_entry *entry;
struct ftrace_hash *free_hash = NULL;
struct dyn_ftrace *rec;
int ret = -EBUSY;
mutex_lock(&direct_mutex);
/* See if there's a direct function at @ip already */
if (ftrace_find_rec_direct(ip))
goto out_unlock;
ret = -ENODEV;
rec = lookup_rec(ip, ip);
if (!rec)
goto out_unlock;
/*
* Check if the rec says it has a direct call but we didn't
* find one earlier?
*/
if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
goto out_unlock;
/* Make sure the ip points to the exact record */
if (ip != rec->ip) {
ip = rec->ip;
/* Need to check this ip for a direct. */
if (ftrace_find_rec_direct(ip))
goto out_unlock;
}
ret = -ENOMEM;
if (ftrace_hash_empty(direct_functions) ||
direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
struct ftrace_hash *new_hash;
int size = ftrace_hash_empty(direct_functions) ? 0 :
direct_functions->count + 1;
if (size < 32)
size = 32;
new_hash = dup_hash(direct_functions, size);
if (!new_hash)
goto out_unlock;
free_hash = direct_functions;
direct_functions = new_hash;
}
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
if (!entry)
goto out_unlock;
direct = ftrace_find_direct_func(addr);
if (!direct) {
direct = kmalloc(sizeof(*direct), GFP_KERNEL);
if (!direct) {
kfree(entry);
goto out_unlock;
}
direct->addr = addr;
direct->count = 0;
list_add_rcu(&direct->next, &ftrace_direct_funcs);
ftrace_direct_func_count++;
}
entry->ip = ip;
entry->direct = addr;
__add_hash_entry(direct_functions, entry);
ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
if (ret)
remove_hash_entry(direct_functions, entry);
if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
ret = register_ftrace_function(&direct_ops);
if (ret)
ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
}
if (ret) {
kfree(entry);
if (!direct->count) {
list_del_rcu(&direct->next);
synchronize_rcu_tasks();
kfree(direct);
if (free_hash)
free_ftrace_hash(free_hash);
free_hash = NULL;
ftrace_direct_func_count--;
}
} else {
direct->count++;
}
out_unlock:
mutex_unlock(&direct_mutex);
if (free_hash) {
synchronize_rcu_tasks();
free_ftrace_hash(free_hash);
}
return ret;
}
EXPORT_SYMBOL_GPL(register_ftrace_direct);
static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
struct dyn_ftrace **recp)
{
struct ftrace_func_entry *entry;
struct dyn_ftrace *rec;
rec = lookup_rec(*ip, *ip);
if (!rec)
return NULL;
entry = __ftrace_lookup_ip(direct_functions, rec->ip);
if (!entry) {
WARN_ON(rec->flags & FTRACE_FL_DIRECT);
return NULL;
}
WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
/* Passed in ip just needs to be on the call site */
*ip = rec->ip;
if (recp)
*recp = rec;
return entry;
}
int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
{
struct ftrace_direct_func *direct;
struct ftrace_func_entry *entry;
int ret = -ENODEV;
mutex_lock(&direct_mutex);
entry = find_direct_entry(&ip, NULL);
if (!entry)
goto out_unlock;
if (direct_functions->count == 1)
unregister_ftrace_function(&direct_ops);
ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
WARN_ON(ret);
remove_hash_entry(direct_functions, entry);
direct = ftrace_find_direct_func(addr);
if (!WARN_ON(!direct)) {
/* This is the good path (see the ! before WARN) */
direct->count--;
WARN_ON(direct->count < 0);
if (!direct->count) {
list_del_rcu(&direct->next);
synchronize_rcu_tasks();
kfree(direct);
ftrace_direct_func_count--;
}
}
out_unlock:
mutex_unlock(&direct_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
static struct ftrace_ops stub_ops = {
.func = ftrace_stub,
};
/**
* ftrace_modify_direct_caller - modify ftrace nop directly
* @entry: The ftrace hash entry of the direct helper for @rec
* @rec: The record representing the function site to patch
* @old_addr: The location that the site at @rec->ip currently calls
* @new_addr: The location that the site at @rec->ip should call
*
* An architecture may overwrite this function to optimize the
* changing of the direct callback on an ftrace nop location.
* This is called with the ftrace_lock mutex held, and no other
* ftrace callbacks are on the associated record (@rec). Thus,
* it is safe to modify the ftrace record, where it should be
* currently calling @old_addr directly, to call @new_addr.
*
* Safety checks should be made to make sure that the code at
* @rec->ip is currently calling @old_addr. And this must
* also update entry->direct to @new_addr.
*/
int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
struct dyn_ftrace *rec,
unsigned long old_addr,
unsigned long new_addr)
{
unsigned long ip = rec->ip;
int ret;
/*
* The ftrace_lock was used to determine if the record
* had more than one registered user to it. If it did,
* we needed to prevent that from changing to do the quick
* switch. But if it did not (only a direct caller was attached)
* then this function is called. But this function can deal
* with attached callers to the rec that we care about, and
* since this function uses standard ftrace calls that take
* the ftrace_lock mutex, we need to release it.
*/
mutex_unlock(&ftrace_lock);
/*
* By setting a stub function at the same address, we force
* the code to call the iterator and the direct_ops helper.
* This means that @ip does not call the direct call, and
* we can simply modify it.
*/
ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
if (ret)
goto out_lock;
ret = register_ftrace_function(&stub_ops);
if (ret) {
ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
goto out_lock;
}
entry->direct = new_addr;
/*
* By removing the stub, we put back the direct call, calling
* the @new_addr.
*/
unregister_ftrace_function(&stub_ops);
ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
out_lock:
mutex_lock(&ftrace_lock);
return ret;
}
/**
* modify_ftrace_direct - Modify an existing direct call to call something else
* @ip: The instruction pointer to modify
* @old_addr: The address that the current @ip calls directly
* @new_addr: The address that the @ip should call
*
* This modifies a ftrace direct caller at an instruction pointer without
* having to disable it first. The direct call will switch over to the
* @new_addr without missing anything.
*
* Returns: zero on success. Non zero on error, which includes:
* -ENODEV : the @ip given has no direct caller attached
* -EINVAL : the @old_addr does not match the current direct caller
*/
int modify_ftrace_direct(unsigned long ip,
unsigned long old_addr, unsigned long new_addr)
{
struct ftrace_func_entry *entry;
struct dyn_ftrace *rec;
int ret = -ENODEV;
mutex_lock(&direct_mutex);
mutex_lock(&ftrace_lock);
entry = find_direct_entry(&ip, &rec);
if (!entry)
goto out_unlock;
ret = -EINVAL;
if (entry->direct != old_addr)
goto out_unlock;
/*
* If there's no other ftrace callback on the rec->ip location,
* then it can be changed directly by the architecture.
* If there is another caller, then we just need to change the
* direct caller helper to point to @new_addr.
*/
if (ftrace_rec_count(rec) == 1) {
ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
} else {
entry->direct = new_addr;
ret = 0;
}
out_unlock:
mutex_unlock(&ftrace_lock);
mutex_unlock(&direct_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(modify_ftrace_direct);
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
/**
* ftrace_set_filter_ip - set a function to filter on in ftrace by address
* @ops - the ops to set the filter with
* @ip - the address to add to or remove from the filter.
* @remove - non zero to remove the ip from the filter
* @reset - non zero to reset all filters before applying this filter.
*
* Filters denote which functions should be enabled when tracing is enabled
* If @ip is NULL, it failes to update filter.
*/
int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
int remove, int reset)
{
ftrace_ops_init(ops);
return ftrace_set_addr(ops, ip, remove, reset, 1);
}
EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
/**
* ftrace_ops_set_global_filter - setup ops to use global filters
* @ops - the ops which will use the global filters
*
* ftrace users who need global function trace filtering should call this.
* It can set the global filter only if ops were not initialized before.
*/
void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
{
if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
return;
ftrace_ops_init(ops);
ops->func_hash = &global_ops.local_hash;
}
EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
static int
ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
int reset, int enable)
{
return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
}
/**
* 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.
*/
int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
int len, int reset)
{
ftrace_ops_init(ops);
return 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.
*/
int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
int len, int reset)
{
ftrace_ops_init(ops);
return ftrace_set_regex(ops, buf, len, reset, 0);
}
EXPORT_SYMBOL_GPL(ftrace_set_notrace);
/**
* ftrace_set_global_filter - set a function to filter on with global tracers
* @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_global_notrace - set a function to not trace with global tracers
* @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;
/* Used by function selftest to not test if filter is set */
bool ftrace_filter_param __initdata;
static int __init set_ftrace_notrace(char *str)
{
ftrace_filter_param = true;
strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
return 1;
}
__setup("ftrace_notrace=", set_ftrace_notrace);
static int __init set_ftrace_filter(char *str)
{
ftrace_filter_param = true;
strlcpy(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 char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
static int ftrace_graph_set_hash(struct ftrace_hash *hash, 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 int __init set_graph_notrace_function(char *str)
{
strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
return 1;
}
__setup("ftrace_graph_notrace=", set_graph_notrace_function);
static int __init set_graph_max_depth_function(char *str)
{
if (!str)
return 0;
fgraph_max_depth = simple_strtoul(str, NULL, 0);
return 1;
}
__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
static void __init set_ftrace_early_graph(char *buf, int enable)
{
int ret;
char *func;
struct ftrace_hash *hash;
hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
return;
while (buf) {
func = strsep(&buf, ",");
/* we allow only one expression at a time */
ret = ftrace_graph_set_hash(hash, func);
if (ret)
printk(KERN_DEBUG "ftrace: function %s not "
"traceable\n", func);
}
if (enable)
ftrace_graph_hash = hash;
else
ftrace_graph_notrace_hash = hash;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
void __init
ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
{
char *func;
ftrace_ops_init(ops);
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])
ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
if (ftrace_notrace_buf[0])
ftrace_set_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, 1);
if (ftrace_graph_notrace_buf[0])
set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
}
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;
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)) {
ftrace_match_records(iter->hash, parser->buffer, parser->idx);
}
trace_parser_put(parser);
mutex_lock(&iter->ops->func_hash->regex_lock);
if (file->f_mode & FMODE_WRITE) {
filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
if (filter_hash) {
orig_hash = &iter->ops->func_hash->filter_hash;
if (iter->tr && !list_empty(&iter->tr->mod_trace))
iter->hash->flags |= FTRACE_HASH_FL_MOD;
} else
orig_hash = &iter->ops->func_hash->notrace_hash;
mutex_lock(&ftrace_lock);
ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
iter->hash, filter_hash);
mutex_unlock(&ftrace_lock);
} else {
/* For read only, the hash is the ops hash */
iter->hash = NULL;
}
mutex_unlock(&iter->ops->func_hash->regex_lock);
free_ftrace_hash(iter->hash);
if (iter->tr)
trace_array_put(iter->tr);
kfree(iter);
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 = tracing_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 = tracing_lseek,
.release = ftrace_regex_release,
};
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static DEFINE_MUTEX(graph_lock);
struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
enum graph_filter_type {
GRAPH_FILTER_NOTRACE = 0,
GRAPH_FILTER_FUNCTION,
};
#define FTRACE_GRAPH_EMPTY ((void *)1)
struct ftrace_graph_data {
struct ftrace_hash *hash;
struct ftrace_func_entry *entry;
int idx; /* for hash table iteration */
enum graph_filter_type type;
struct ftrace_hash *new_hash;
const struct seq_operations *seq_ops;
struct trace_parser parser;
};
static void *
__g_next(struct seq_file *m, loff_t *pos)
{
struct ftrace_graph_data *fgd = m->private;
struct ftrace_func_entry *entry = fgd->entry;
struct hlist_head *head;
int i, idx = fgd->idx;
if (*pos >= fgd->hash->count)
return NULL;
if (entry) {
hlist_for_each_entry_continue(entry, hlist) {
fgd->entry = entry;
return entry;
}
idx++;
}
for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
head = &fgd->hash->buckets[i];
hlist_for_each_entry(entry, head, hlist) {
fgd->entry = entry;
fgd->idx = i;
return entry;
}
}
return NULL;
}
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)
{
struct ftrace_graph_data *fgd = m->private;
mutex_lock(&graph_lock);
if (fgd->type == GRAPH_FILTER_FUNCTION)
fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
lockdep_is_held(&graph_lock));
else
fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
lockdep_is_held(&graph_lock));
/* Nothing, tell g_show to print all functions are enabled */
if (ftrace_hash_empty(fgd->hash) && !*pos)
return FTRACE_GRAPH_EMPTY;
fgd->idx = 0;
fgd->entry = NULL;
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)
{
struct ftrace_func_entry *entry = v;
if (!entry)
return 0;
if (entry == FTRACE_GRAPH_EMPTY) {
struct ftrace_graph_data *fgd = m->private;
if (fgd->type == GRAPH_FILTER_FUNCTION)
seq_puts(m, "#### all functions enabled ####\n");
else
seq_puts(m, "#### no functions disabled ####\n");
return 0;
}
seq_printf(m, "%ps\n", (void *)entry->ip);
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,
struct ftrace_graph_data *fgd)
{
int ret;
struct ftrace_hash *new_hash = NULL;
ret = security_locked_down(LOCKDOWN_TRACEFS);
if (ret)
return ret;
if (file->f_mode & FMODE_WRITE) {
const int size_bits = FTRACE_HASH_DEFAULT_BITS;
if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
return -ENOMEM;
if (file->f_flags & O_TRUNC)
new_hash = alloc_ftrace_hash(size_bits);
else
new_hash = alloc_and_copy_ftrace_hash(size_bits,
fgd->hash);
if (!new_hash) {
ret = -ENOMEM;
goto out;
}
}
if (file->f_mode & FMODE_READ) {
ret = seq_open(file, &ftrace_graph_seq_ops);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = fgd;
} else {
/* Failed */
free_ftrace_hash(new_hash);
new_hash = NULL;
}
} else
file->private_data = fgd;
out:
if (ret < 0 && file->f_mode & FMODE_WRITE)
trace_parser_put(&fgd->parser);
fgd->new_hash = new_hash;
/*
* All uses of fgd->hash must be taken with the graph_lock
* held. The graph_lock is going to be released, so force
* fgd->hash to be reinitialized when it is taken again.
*/
fgd->hash = NULL;
return ret;
}
static int
ftrace_graph_open(struct inode *inode, struct file *file)
{
struct ftrace_graph_data *fgd;
int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
if (fgd == NULL)
return -ENOMEM;
mutex_lock(&graph_lock);
fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
lockdep_is_held(&graph_lock));
fgd->type = GRAPH_FILTER_FUNCTION;
fgd->seq_ops = &ftrace_graph_seq_ops;
ret = __ftrace_graph_open(inode, file, fgd);
if (ret < 0)
kfree(fgd);
mutex_unlock(&graph_lock);
return ret;
}
static int
ftrace_graph_notrace_open(struct inode *inode, struct file *file)
{
struct ftrace_graph_data *fgd;
int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
if (fgd == NULL)
return -ENOMEM;
mutex_lock(&graph_lock);
fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
lockdep_is_held(&graph_lock));
fgd->type = GRAPH_FILTER_NOTRACE;
fgd->seq_ops = &ftrace_graph_seq_ops;
ret = __ftrace_graph_open(inode, file, fgd);
if (ret < 0)
kfree(fgd);
mutex_unlock(&graph_lock);
return ret;
}
static int
ftrace_graph_release(struct inode *inode, struct file *file)
{
struct ftrace_graph_data *fgd;
struct ftrace_hash *old_hash, *new_hash;
struct trace_parser *parser;
int ret = 0;
if (file->f_mode & FMODE_READ) {
struct seq_file *m = file->private_data;
fgd = m->private;
seq_release(inode, file);
} else {
fgd = file->private_data;
}
if (file->f_mode & FMODE_WRITE) {
parser = &fgd->parser;
if (trace_parser_loaded((parser))) {
ret = ftrace_graph_set_hash(fgd->new_hash,
parser->buffer);
}
trace_parser_put(parser);
new_hash = __ftrace_hash_move(fgd->new_hash);
if (!new_hash) {
ret = -ENOMEM;
goto out;
}
mutex_lock(&graph_lock);
if (fgd->type == GRAPH_FILTER_FUNCTION) {
old_hash = rcu_dereference_protected(ftrace_graph_hash,
lockdep_is_held(&graph_lock));
rcu_assign_pointer(ftrace_graph_hash, new_hash);
} else {
old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
lockdep_is_held(&graph_lock));
rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
}
mutex_unlock(&graph_lock);
/*
* We need to do a hard force of sched synchronization.
* This is because we use preempt_disable() to do RCU, but
* the function tracers can be called where RCU is not watching
* (like before user_exit()). We can not rely on the RCU
* infrastructure to do the synchronization, thus we must do it
* ourselves.
*/
schedule_on_each_cpu(ftrace_sync);
free_ftrace_hash(old_hash);
}
out:
free_ftrace_hash(fgd->new_hash);
kfree(fgd);
return ret;
}
static int
ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
{
struct ftrace_glob func_g;
struct dyn_ftrace *rec;
struct ftrace_page *pg;
struct ftrace_func_entry *entry;
int fail = 1;
int not;
/* decode regex */
func_g.type = filter_parse_regex(buffer, strlen(buffer),
&func_g.search, &not);
func_g.len = strlen(func_g.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_DISABLED)
continue;
if (ftrace_match_record(rec, &func_g, NULL, 0)) {
entry = ftrace_lookup_ip(hash, rec->ip);
if (!not) {
fail = 0;
if (entry)
continue;
if (add_hash_entry(hash, rec->ip) < 0)
goto out;
} else {
if (entry) {
free_hash_entry(hash, entry);
fail = 0;
}
}
}
} while_for_each_ftrace_rec();
out:
mutex_unlock(&ftrace_lock);
if (fail)
return -EINVAL;
return 0;
}
static ssize_t
ftrace_graph_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
ssize_t read, ret = 0;
struct ftrace_graph_data *fgd = file->private_data;
struct trace_parser *parser;
if (!cnt)
return 0;
/* Read mode uses seq functions */
if (file->f_mode & FMODE_READ) {
struct seq_file *m = file->private_data;
fgd = m->private;
}
parser = &fgd->parser;
read = trace_get_user(parser, ubuf, cnt, ppos);
if (read >= 0 && trace_parser_loaded(parser) &&
!trace_parser_cont(parser)) {
ret = ftrace_graph_set_hash(fgd->new_hash,
parser->buffer);
trace_parser_clear(parser);
}
if (!ret)
ret = read;
return ret;
}
static const struct file_operations ftrace_graph_fops = {
.open = ftrace_graph_open,
.read = seq_read,
.write = ftrace_graph_write,
.llseek = tracing_lseek,
.release = ftrace_graph_release,
};
static const struct file_operations ftrace_graph_notrace_fops = {
.open = ftrace_graph_notrace_open,
.read = seq_read,
.write = ftrace_graph_write,
.llseek = tracing_lseek,
.release = ftrace_graph_release,
};
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
void ftrace_create_filter_files(struct ftrace_ops *ops,
struct dentry *parent)
{
trace_create_file("set_ftrace_filter", 0644, parent,
ops, &ftrace_filter_fops);
trace_create_file("set_ftrace_notrace", 0644, parent,
ops, &ftrace_notrace_fops);
}
/*
* The name "destroy_filter_files" is really a misnomer. Although
* in the future, it may actually delete the files, but this is
* really intended to make sure the ops passed in are disabled
* and that when this function returns, the caller is free to
* free the ops.
*
* The "destroy" name is only to match the "create" name that this
* should be paired with.
*/
void ftrace_destroy_filter_files(struct ftrace_ops *ops)
{
mutex_lock(&ftrace_lock);
if (ops->flags & FTRACE_OPS_FL_ENABLED)
ftrace_shutdown(ops, 0);
ops->flags |= FTRACE_OPS_FL_DELETED;
ftrace_free_filter(ops);
mutex_unlock(&ftrace_lock);
}
static __init int ftrace_init_dyn_tracefs(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);
ftrace_create_filter_files(&global_ops, d_tracer);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
trace_create_file("set_graph_function", 0644, d_tracer,
NULL,
&ftrace_graph_fops);
trace_create_file("set_graph_notrace", 0644, d_tracer,
NULL,
&ftrace_graph_notrace_fops);
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
return 0;
}
static int ftrace_cmp_ips(const void *a, const void *b)
{
const unsigned long *ipa = a;
const unsigned long *ipb = b;
if (*ipa > *ipb)
return 1;
if (*ipa < *ipb)
return -1;
return 0;
}
static int ftrace_process_locs(struct module *mod,
unsigned long *start,
unsigned long *end)
{
struct ftrace_page *start_pg;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
unsigned long count;
unsigned long *p;
unsigned long addr;
unsigned long flags = 0; /* Shut up gcc */
int ret = -ENOMEM;
count = end - start;
if (!count)
return 0;
sort(start, count, sizeof(*start),
ftrace_cmp_ips, NULL);
start_pg = ftrace_allocate_pages(count);
if (!start_pg)
return -ENOMEM;
mutex_lock(&ftrace_lock);
/*
* Core and each module needs their own pages, as
* modules will free them when they are removed.
* Force a new page to be allocated for modules.
*/
if (!mod) {
WARN_ON(ftrace_pages || ftrace_pages_start);
/* First initialization */
ftrace_pages = ftrace_pages_start = start_pg;
} else {
if (!ftrace_pages)
goto out;
if (WARN_ON(ftrace_pages->next)) {
/* Hmm, we have free pages? */
while (ftrace_pages->next)
ftrace_pages = ftrace_pages->next;
}
ftrace_pages->next = start_pg;
}
p = start;
pg = start_pg;
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;
if (pg->index == pg->size) {
/* We should have allocated enough */
if (WARN_ON(!pg->next))
break;
pg = pg->next;
}
rec = &pg->records[pg->index++];
rec->ip = addr;
}
/* We should have used all pages */
WARN_ON(pg->next);
/* Assign the last page to ftrace_pages */
ftrace_pages = pg;
/*
* 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, start_pg);
if (!mod)
local_irq_restore(flags);
ret = 0;
out:
mutex_unlock(&ftrace_lock);
return ret;
}
struct ftrace_mod_func {
struct list_head list;
char *name;
unsigned long ip;
unsigned int size;
};
struct ftrace_mod_map {
struct rcu_head rcu;
struct list_head list;
struct module *mod;
unsigned long start_addr;
unsigned long end_addr;
struct list_head funcs;
unsigned int num_funcs;
};
#ifdef CONFIG_MODULES
#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
static LIST_HEAD(ftrace_mod_maps);
static int referenced_filters(struct dyn_ftrace *rec)
{
struct ftrace_ops *ops;
int cnt = 0;
for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
if (ops_references_rec(ops, rec))
cnt++;
}
return cnt;
}
static void
clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
{
struct ftrace_func_entry *entry;
struct dyn_ftrace *rec;
int i;
if (ftrace_hash_empty(hash))
return;
for (i = 0; i < pg->index; i++) {
rec = &pg->records[i];
entry = __ftrace_lookup_ip(hash, rec->ip);
/*
* Do not allow this rec to match again.
* Yeah, it may waste some memory, but will be removed
* if/when the hash is modified again.
*/
if (entry)
entry->ip = 0;
}
}
/* Clear any records from hashs */
static void clear_mod_from_hashes(struct ftrace_page *pg)
{
struct trace_array *tr;
mutex_lock(&trace_types_lock);
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
if (!tr->ops || !tr->ops->func_hash)
continue;
mutex_lock(&tr->ops->func_hash->regex_lock);
clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
mutex_unlock(&tr->ops->func_hash->regex_lock);
}
mutex_unlock(&trace_types_lock);
}
static void ftrace_free_mod_map(struct rcu_head *rcu)
{
struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
struct ftrace_mod_func *mod_func;
struct ftrace_mod_func *n;
/* All the contents of mod_map are now not visible to readers */
list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
kfree(mod_func->name);
list_del(&mod_func->list);
kfree(mod_func);
}
kfree(mod_map);
}
void ftrace_release_mod(struct module *mod)
{
struct ftrace_mod_map *mod_map;
struct ftrace_mod_map *n;
struct dyn_ftrace *rec;
struct ftrace_page **last_pg;
struct ftrace_page *tmp_page = NULL;
struct ftrace_page *pg;
int order;
mutex_lock(&ftrace_lock);
if (ftrace_disabled)
goto out_unlock;
list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
if (mod_map->mod == mod) {
list_del_rcu(&mod_map->list);
call_rcu(&mod_map->rcu, ftrace_free_mod_map);
break;
}
}
/*
* Each module has its own ftrace_pages, remove
* them from the list.
*/
last_pg = &ftrace_pages_start;
for (pg = ftrace_pages_start; pg; pg = *last_pg) {
rec = &pg->records[0];
if (within_module_core(rec->ip, mod) ||
within_module_init(rec->ip, mod)) {
/*
* As core pages are first, the first
* page should never be a module page.
*/
if (WARN_ON(pg == ftrace_pages_start))
goto out_unlock;
/* Check if we are deleting the last page */
if (pg == ftrace_pages)
ftrace_pages = next_to_ftrace_page(last_pg);
ftrace_update_tot_cnt -= pg->index;
*last_pg = pg->next;
pg->next = tmp_page;
tmp_page = pg;
} else
last_pg = &pg->next;
}
out_unlock:
mutex_unlock(&ftrace_lock);
for (pg = tmp_page; pg; pg = tmp_page) {
/* Needs to be called outside of ftrace_lock */
clear_mod_from_hashes(pg);
order = get_count_order(pg->size / ENTRIES_PER_PAGE);
free_pages((unsigned long)pg->records, order);
tmp_page = pg->next;
kfree(pg);
ftrace_number_of_pages -= 1 << order;
ftrace_number_of_groups--;
}
}
void ftrace_module_enable(struct module *mod)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
mutex_lock(&ftrace_lock);
if (ftrace_disabled)
goto out_unlock;
/*
* If the tracing is enabled, go ahead and enable the record.
*
* The reason not to enable the record immediately 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.
*
* We also delay this to after the module code already set the
* text to read-only, as we now need to set it back to read-write
* so that we can modify the text.
*/
if (ftrace_start_up)
ftrace_arch_code_modify_prepare();
do_for_each_ftrace_rec(pg, rec) {
int cnt;
/*
* do_for_each_ftrace_rec() is a double loop.
* module text shares the pg. If a record is
* not part of this module, then skip this pg,
* which the "break" will do.
*/
if (!within_module_core(rec->ip, mod) &&
!within_module_init(rec->ip, mod))
break;
cnt = 0;
/*
* When adding a module, we need to check if tracers are
* currently enabled and if they are, and can trace this record,
* we need to enable the module functions as well as update the
* reference counts for those function records.
*/
if (ftrace_start_up)
cnt += referenced_filters(rec);
/* This clears FTRACE_FL_DISABLED */
rec->flags = cnt;
if (ftrace_start_up && cnt) {
int failed = __ftrace_replace_code(rec, 1);
if (failed) {
ftrace_bug(failed, rec);
goto out_loop;
}
}
} while_for_each_ftrace_rec();
out_loop:
if (ftrace_start_up)
ftrace_arch_code_modify_post_process();
out_unlock:
mutex_unlock(&ftrace_lock);
process_cached_mods(mod->name);
}
void ftrace_module_init(struct module *mod)
{
if (ftrace_disabled || !mod->num_ftrace_callsites)
return;
ftrace_process_locs(mod, mod->ftrace_callsites,
mod->ftrace_callsites + mod->num_ftrace_callsites);
}
static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
struct dyn_ftrace *rec)
{
struct ftrace_mod_func *mod_func;
unsigned long symsize;
unsigned long offset;
char str[KSYM_SYMBOL_LEN];
char *modname;
const char *ret;
ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
if (!ret)
return;
mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
if (!mod_func)
return;
mod_func->name = kstrdup(str, GFP_KERNEL);
if (!mod_func->name) {
kfree(mod_func);
return;
}
mod_func->ip = rec->ip - offset;
mod_func->size = symsize;
mod_map->num_funcs++;
list_add_rcu(&mod_func->list, &mod_map->funcs);
}
static struct ftrace_mod_map *
allocate_ftrace_mod_map(struct module *mod,
unsigned long start, unsigned long end)
{
struct ftrace_mod_map *mod_map;
mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
if (!mod_map)
return NULL;
mod_map->mod = mod;
mod_map->start_addr = start;
mod_map->end_addr = end;
mod_map->num_funcs = 0;
INIT_LIST_HEAD_RCU(&mod_map->funcs);
list_add_rcu(&mod_map->list, &ftrace_mod_maps);
return mod_map;
}
static const char *
ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
unsigned long addr, unsigned long *size,
unsigned long *off, char *sym)
{
struct ftrace_mod_func *found_func = NULL;
struct ftrace_mod_func *mod_func;
list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
if (addr >= mod_func->ip &&
addr < mod_func->ip + mod_func->size) {
found_func = mod_func;
break;
}
}
if (found_func) {
if (size)
*size = found_func->size;
if (off)
*off = addr - found_func->ip;
if (sym)
strlcpy(sym, found_func->name, KSYM_NAME_LEN);
return found_func->name;
}
return NULL;
}
const char *
ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
unsigned long *off, char **modname, char *sym)
{
struct ftrace_mod_map *mod_map;
const char *ret = NULL;
/* mod_map is freed via call_rcu() */
preempt_disable();
list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
if (ret) {
if (modname)
*modname = mod_map->mod->name;
break;
}
}
preempt_enable();
return ret;
}
int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
char *type, char *name,
char *module_name, int *exported)
{
struct ftrace_mod_map *mod_map;
struct ftrace_mod_func *mod_func;
preempt_disable();
list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
if (symnum >= mod_map->num_funcs) {
symnum -= mod_map->num_funcs;
continue;
}
list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
if (symnum > 1) {
symnum--;
continue;
}
*value = mod_func->ip;
*type = 'T';
strlcpy(name, mod_func->name, KSYM_NAME_LEN);
strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
*exported = 1;
preempt_enable();
return 0;
}
WARN_ON(1);
break;
}
preempt_enable();
return -ERANGE;
}
#else
static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
struct dyn_ftrace *rec) { }
static inline struct ftrace_mod_map *
allocate_ftrace_mod_map(struct module *mod,
unsigned long start, unsigned long end)
{
return NULL;
}
#endif /* CONFIG_MODULES */
struct ftrace_init_func {
struct list_head list;
unsigned long ip;
};
/* Clear any init ips from hashes */
static void
clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
{
struct ftrace_func_entry *entry;
entry = ftrace_lookup_ip(hash, func->ip);
/*
* Do not allow this rec to match again.
* Yeah, it may waste some memory, but will be removed
* if/when the hash is modified again.
*/
if (entry)
entry->ip = 0;
}
static void
clear_func_from_hashes(struct ftrace_init_func *func)
{
struct trace_array *tr;
mutex_lock(&trace_types_lock);
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
if (!tr->ops || !tr->ops->func_hash)
continue;
mutex_lock(&tr->ops->func_hash->regex_lock);
clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
mutex_unlock(&tr->ops->func_hash->regex_lock);
}
mutex_unlock(&trace_types_lock);
}
static void add_to_clear_hash_list(struct list_head *clear_list,
struct dyn_ftrace *rec)
{
struct ftrace_init_func *func;
func = kmalloc(sizeof(*func), GFP_KERNEL);
if (!func) {
MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
return;
}
func->ip = rec->ip;
list_add(&func->list, clear_list);
}
void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
{
unsigned long start = (unsigned long)(start_ptr);
unsigned long end = (unsigned long)(end_ptr);
struct ftrace_page **last_pg = &ftrace_pages_start;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
struct dyn_ftrace key;
struct ftrace_mod_map *mod_map = NULL;
struct ftrace_init_func *func, *func_next;
struct list_head clear_hash;
int order;
INIT_LIST_HEAD(&clear_hash);
key.ip = start;
key.flags = end; /* overload flags, as it is unsigned long */
mutex_lock(&ftrace_lock);
/*
* If we are freeing module init memory, then check if
* any tracer is active. If so, we need to save a mapping of
* the module functions being freed with the address.
*/
if (mod && ftrace_ops_list != &ftrace_list_end)
mod_map = allocate_ftrace_mod_map(mod, start, end);
for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
if (end < pg->records[0].ip ||
start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
continue;
again:
rec = bsearch(&key, pg->records, pg->index,
sizeof(struct dyn_ftrace),
ftrace_cmp_recs);
if (!rec)
continue;
/* rec will be cleared from hashes after ftrace_lock unlock */
add_to_clear_hash_list(&clear_hash, rec);
if (mod_map)
save_ftrace_mod_rec(mod_map, rec);
pg->index--;
ftrace_update_tot_cnt--;
if (!pg->index) {
*last_pg = pg->next;
order = get_count_order(pg->size / ENTRIES_PER_PAGE);
free_pages((unsigned long)pg->records, order);
ftrace_number_of_pages -= 1 << order;
ftrace_number_of_groups--;
kfree(pg);
pg = container_of(last_pg, struct ftrace_page, next);
if (!(*last_pg))
ftrace_pages = pg;
continue;
}
memmove(rec, rec + 1,
(pg->index - (rec - pg->records)) * sizeof(*rec));
/* More than one function may be in this block */
goto again;
}
mutex_unlock(&ftrace_lock);
list_for_each_entry_safe(func, func_next, &clear_hash, list) {
clear_func_from_hashes(func);
kfree(func);
}
}
void __init ftrace_free_init_mem(void)
{
void *start = (void *)(&__init_begin);
void *end = (void *)(&__init_end);
ftrace_free_mem(NULL, start, end);
}
void __init ftrace_init(void)
{
extern unsigned long __start_mcount_loc[];
extern unsigned long __stop_mcount_loc[];
unsigned long count, flags;
int ret;
local_irq_save(flags);
ret = ftrace_dyn_arch_init();
local_irq_restore(flags);
if (ret)
goto failed;
count = __stop_mcount_loc - __start_mcount_loc;
if (!count) {
pr_info("ftrace: No functions to be traced?\n");
goto failed;
}
pr_info("ftrace: allocating %ld entries in %ld pages\n",
count, count / ENTRIES_PER_PAGE + 1);
last_ftrace_enabled = ftrace_enabled = 1;
ret = ftrace_process_locs(NULL,
__start_mcount_loc,
__stop_mcount_loc);
pr_info("ftrace: allocated %ld pages with %ld groups\n",
ftrace_number_of_pages, ftrace_number_of_groups);
set_ftrace_early_filters();
return;
failed:
ftrace_disabled = 1;
}
/* Do nothing if arch does not support this */
void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
{
}
static void ftrace_update_trampoline(struct ftrace_ops *ops)
{
arch_ftrace_update_trampoline(ops);
}
void ftrace_init_trace_array(struct trace_array *tr)
{
INIT_LIST_HEAD(&tr->func_probes);
INIT_LIST_HEAD(&tr->mod_trace);
INIT_LIST_HEAD(&tr->mod_notrace);
}
#else
struct ftrace_ops global_ops = {
.func = ftrace_stub,
.flags = FTRACE_OPS_FL_RECURSION_SAFE |
FTRACE_OPS_FL_INITIALIZED |
FTRACE_OPS_FL_PID,
};
static int __init ftrace_nodyn_init(void)
{
ftrace_enabled = 1;
return 0;
}
core_initcall(ftrace_nodyn_init);
static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
static inline void ftrace_startup_enable(int command) { }
static inline void ftrace_startup_all(int command) { }
# define ftrace_startup_sysctl() do { } while (0)
# define ftrace_shutdown_sysctl() do { } while (0)
static void ftrace_update_trampoline(struct ftrace_ops *ops)
{
}
#endif /* CONFIG_DYNAMIC_FTRACE */
__init void ftrace_init_global_array_ops(struct trace_array *tr)
{
tr->ops = &global_ops;
tr->ops->private = tr;
ftrace_init_trace_array(tr);
}
void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
{
/* If we filter on pids, update to use the pid function */
if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
if (WARN_ON(tr->ops->func != ftrace_stub))
printk("ftrace ops had %pS for function\n",
tr->ops->func);
}
tr->ops->func = func;
tr->ops->private = tr;
}
void ftrace_reset_array_ops(struct trace_array *tr)
{
tr->ops->func = ftrace_stub;
}
static nokprobe_inline void
__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ignored, struct pt_regs *regs)
{
struct ftrace_ops *op;
int bit;
bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
if (bit < 0)
return;
/*
* Some of the ops may be dynamically allocated,
* they must be freed after a synchronize_rcu().
*/
preempt_disable_notrace();
do_for_each_ftrace_op(op, ftrace_ops_list) {
/* Stub functions don't need to be called nor tested */
if (op->flags & FTRACE_OPS_FL_STUB)
continue;
/*
* Check the following for each ops before calling their func:
* if RCU flag is set, then rcu_is_watching() must be true
* if PER_CPU is set, then ftrace_function_local_disable()
* must be false
* Otherwise test if the ip matches the ops filter
*
* If any of the above fails then the op->func() is not executed.
*/
if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
ftrace_ops_test(op, ip, regs)) {
if (FTRACE_WARN_ON(!op->func)) {
pr_warn("op=%p %pS\n", op, op);
goto out;
}
op->func(ip, parent_ip, op, regs);
}
} while_for_each_ftrace_op(op);
out:
preempt_enable_notrace();
trace_clear_recursion(bit);
}
/*
* Some archs only support passing ip and parent_ip. Even though
* the list function ignores the op parameter, we do not want any
* C side effects, where a function is called without the caller
* sending a third parameter.
* Archs are to support both the regs and ftrace_ops at the same time.
* If they support ftrace_ops, it is assumed they support regs.
* If call backs want to use regs, they must either check for regs
* being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
* Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
* An architecture can pass partial regs with ftrace_ops and still
* set the ARCH_SUPPORTS_FTRACE_OPS.
*/
#if ARCH_SUPPORTS_FTRACE_OPS
static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
__ftrace_ops_list_func(ip, parent_ip, NULL, regs);
}
NOKPROBE_SYMBOL(ftrace_ops_list_func);
#else
static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
{
__ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
}
NOKPROBE_SYMBOL(ftrace_ops_no_ops);
#endif
/*
* If there's only one function registered but it does not support
* recursion, needs RCU protection and/or requires per cpu handling, then
* this function will be called by the mcount trampoline.
*/
static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
int bit;
if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
return;
bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
if (bit < 0)
return;
preempt_disable_notrace();
op->func(ip, parent_ip, op, regs);
preempt_enable_notrace();
trace_clear_recursion(bit);
}
NOKPROBE_SYMBOL(ftrace_ops_assist_func);
/**
* ftrace_ops_get_func - get the function a trampoline should call
* @ops: the ops to get the function for
*
* Normally the mcount trampoline will call the ops->func, but there
* are times that it should not. For example, if the ops does not
* have its own recursion protection, then it should call the
* ftrace_ops_assist_func() instead.
*
* Returns the function that the trampoline should call for @ops.
*/
ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
{
/*
* If the function does not handle recursion, needs to be RCU safe,
* or does per cpu logic, then we need to call the assist handler.
*/
if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
ops->flags & FTRACE_OPS_FL_RCU)
return ftrace_ops_assist_func;
return ops->func;
}
static void
ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
struct task_struct *prev, struct task_struct *next)
{
struct trace_array *tr = data;
struct trace_pid_list *pid_list;
pid_list = rcu_dereference_sched(tr->function_pids);
this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
trace_ignore_this_task(pid_list, next));
}
static void
ftrace_pid_follow_sched_process_fork(void *data,
struct task_struct *self,
struct task_struct *task)
{
struct trace_pid_list *pid_list;
struct trace_array *tr = data;
pid_list = rcu_dereference_sched(tr->function_pids);
trace_filter_add_remove_task(pid_list, self, task);
}
static void
ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
{
struct trace_pid_list *pid_list;
struct trace_array *tr = data;
pid_list = rcu_dereference_sched(tr->function_pids);
trace_filter_add_remove_task(pid_list, NULL, task);
}
void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
{
if (enable) {
register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
tr);
register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
tr);
} else {
unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
tr);
unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
tr);
}
}
static void clear_ftrace_pids(struct trace_array *tr)
{
struct trace_pid_list *pid_list;
int cpu;
pid_list = rcu_dereference_protected(tr->function_pids,
lockdep_is_held(&ftrace_lock));
if (!pid_list)
return;
unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
for_each_possible_cpu(cpu)
per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = false;
rcu_assign_pointer(tr->function_pids, NULL);
/* Wait till all users are no longer using pid filtering */
synchronize_rcu();
trace_free_pid_list(pid_list);
}
void ftrace_clear_pids(struct trace_array *tr)
{
mutex_lock(&ftrace_lock);
clear_ftrace_pids(tr);
mutex_unlock(&ftrace_lock);
}
static void ftrace_pid_reset(struct trace_array *tr)
{
mutex_lock(&ftrace_lock);
clear_ftrace_pids(tr);
ftrace_update_pid_func();
ftrace_startup_all(0);
mutex_unlock(&ftrace_lock);
}
/* Greater than any max PID */
#define FTRACE_NO_PIDS (void *)(PID_MAX_LIMIT + 1)
static void *fpid_start(struct seq_file *m, loff_t *pos)
__acquires(RCU)
{
struct trace_pid_list *pid_list;
struct trace_array *tr = m->private;
mutex_lock(&ftrace_lock);
rcu_read_lock_sched();
pid_list = rcu_dereference_sched(tr->function_pids);
if (!pid_list)
return !(*pos) ? FTRACE_NO_PIDS : NULL;
return trace_pid_start(pid_list, pos);
}
static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
{
struct trace_array *tr = m->private;
struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
if (v == FTRACE_NO_PIDS) {
(*pos)++;
return NULL;
}
return trace_pid_next(pid_list, v, pos);
}
static void fpid_stop(struct seq_file *m, void *p)
__releases(RCU)
{
rcu_read_unlock_sched();
mutex_unlock(&ftrace_lock);
}
static int fpid_show(struct seq_file *m, void *v)
{
if (v == FTRACE_NO_PIDS) {
seq_puts(m, "no pid\n");
return 0;
}
return trace_pid_show(m, v);
}
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)
{
struct trace_array *tr = inode->i_private;
struct seq_file *m;
int ret = 0;
ret = tracing_check_open_get_tr(tr);
if (ret)
return ret;
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC))
ftrace_pid_reset(tr);
ret = seq_open(file, &ftrace_pid_sops);
if (ret < 0) {
trace_array_put(tr);
} else {
m = file->private_data;
/* copy tr over to seq ops */
m->private = tr;
}
return ret;
}
static void ignore_task_cpu(void *data)
{
struct trace_array *tr = data;
struct trace_pid_list *pid_list;
/*
* This function is called by on_each_cpu() while the
* event_mutex is held.
*/
pid_list = rcu_dereference_protected(tr->function_pids,
mutex_is_locked(&ftrace_lock));
this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
trace_ignore_this_task(pid_list, current));
}
static ssize_t
ftrace_pid_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct seq_file *m = filp->private_data;
struct trace_array *tr = m->private;
struct trace_pid_list *filtered_pids = NULL;
struct trace_pid_list *pid_list;
ssize_t ret;
if (!cnt)
return 0;
mutex_lock(&ftrace_lock);
filtered_pids = rcu_dereference_protected(tr->function_pids,
lockdep_is_held(&ftrace_lock));
ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
if (ret < 0)
goto out;
rcu_assign_pointer(tr->function_pids, pid_list);
if (filtered_pids) {
synchronize_rcu();
trace_free_pid_list(filtered_pids);
} else if (pid_list) {
/* Register a probe to set whether to ignore the tracing of a task */
register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
}
/*
* Ignoring of pids is done at task switch. But we have to
* check for those tasks that are currently running.
* Always do this in case a pid was appended or removed.
*/
on_each_cpu(ignore_task_cpu, tr, 1);
ftrace_update_pid_func();
ftrace_startup_all(0);
out:
mutex_unlock(&ftrace_lock);
if (ret > 0)
*ppos += ret;
return ret;
}
static int
ftrace_pid_release(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
trace_array_put(tr);
return seq_release(inode, file);
}
static const struct file_operations ftrace_pid_fops = {
.open = ftrace_pid_open,
.write = ftrace_pid_write,
.read = seq_read,
.llseek = tracing_lseek,
.release = ftrace_pid_release,
};
void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
{
trace_create_file("set_ftrace_pid", 0644, d_tracer,
tr, &ftrace_pid_fops);
}
void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
struct dentry *d_tracer)
{
/* Only the top level directory has the dyn_tracefs and profile */
WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
ftrace_init_dyn_tracefs(d_tracer);
ftrace_profile_tracefs(d_tracer);
}
/**
* 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;
ftrace_trace_function = ftrace_stub;
}
/**
* 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;
ftrace_ops_init(ops);
mutex_lock(&ftrace_lock);
ret = ftrace_startup(ops, 0);
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 = ftrace_shutdown(ops, 0);
mutex_unlock(&ftrace_lock);
return ret;
}
EXPORT_SYMBOL_GPL(unregister_ftrace_function);
static bool is_permanent_ops_registered(void)
{
struct ftrace_ops *op;
do_for_each_ftrace_op(op, ftrace_ops_list) {
if (op->flags & FTRACE_OPS_FL_PERMANENT)
return true;
} while_for_each_ftrace_op(op);
return false;
}
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;
if (ftrace_enabled) {
/* we are starting ftrace again */
if (rcu_dereference_protected(ftrace_ops_list,
lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
update_ftrace_function();
ftrace_startup_sysctl();
} else {
if (is_permanent_ops_registered()) {
ftrace_enabled = true;
ret = -EBUSY;
goto out;
}
/* stopping ftrace calls (just send to ftrace_stub) */
ftrace_trace_function = ftrace_stub;
ftrace_shutdown_sysctl();
}
last_ftrace_enabled = !!ftrace_enabled;
out:
mutex_unlock(&ftrace_lock);
return ret;
}
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