unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core

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This commit is contained in:
Ingo Molnar 2011-05-01 19:11:42 +02:00
commit ac0a3260f3
2 changed files with 142 additions and 215 deletions
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8
include/linux/ftrace.h
View file

@ -147,11 +147,9 @@ extern int ftrace_text_reserved(void *start, void *end);
enum {
FTRACE_FL_FREE = (1 << 0),
FTRACE_FL_FAILED = (1 << 1),
FTRACE_FL_FILTER = (1 << 2),
FTRACE_FL_ENABLED = (1 << 3),
FTRACE_FL_NOTRACE = (1 << 4),
FTRACE_FL_CONVERTED = (1 << 5),
FTRACE_FL_FILTER = (1 << 1),
FTRACE_FL_ENABLED = (1 << 2),
FTRACE_FL_NOTRACE = (1 << 3),
};
struct dyn_ftrace {

349
kernel/trace/ftrace.c
View file

@ -39,16 +39,20 @@
#include "trace_stat.h"
#define FTRACE_WARN_ON(cond) \
do { \
if (WARN_ON(cond)) \
({ \
int ___r = cond; \
if (WARN_ON(___r)) \
ftrace_kill(); \
} while (0)
___r; \
})
#define FTRACE_WARN_ON_ONCE(cond) \
do { \
if (WARN_ON_ONCE(cond)) \
({ \
int ___r = cond; \
if (WARN_ON_ONCE(___r)) \
ftrace_kill(); \
} while (0)
___r; \
})
/* hash bits for specific function selection */
#define FTRACE_HASH_BITS 7
@ -147,6 +151,34 @@ static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
}
#endif
static void update_ftrace_function(void)
{
ftrace_func_t func;
/*
* If there's only one function registered, then call that
* function directly. Otherwise, we need to iterate over the
* registered callers.
*/
if (ftrace_list == &ftrace_list_end ||
ftrace_list->next == &ftrace_list_end)
func = ftrace_list->func;
else
func = ftrace_list_func;
/* If we filter on pids, update to use the pid function */
if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
__ftrace_trace_function = func;
ftrace_trace_function = ftrace_test_stop_func;
#endif
}
static int __register_ftrace_function(struct ftrace_ops *ops)
{
ops->next = ftrace_list;
@ -158,30 +190,8 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
*/
rcu_assign_pointer(ftrace_list, ops);
if (ftrace_enabled) {
ftrace_func_t func;
if (ops->next == &ftrace_list_end)
func = ops->func;
else
func = ftrace_list_func;
if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
/*
* For one func, simply call it directly.
* For more than one func, call the chain.
*/
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
__ftrace_trace_function = func;
ftrace_trace_function = ftrace_test_stop_func;
#endif
}
if (ftrace_enabled)
update_ftrace_function();
return 0;
}
@ -209,52 +219,19 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
*p = (*p)->next;
if (ftrace_enabled) {
/* If we only have one func left, then call that directly */
if (ftrace_list->next == &ftrace_list_end) {
ftrace_func_t func = ftrace_list->func;
if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
__ftrace_trace_function = func;
#endif
}
}
if (ftrace_enabled)
update_ftrace_function();
return 0;
}
static void ftrace_update_pid_func(void)
{
ftrace_func_t func;
/* Only do something if we are tracing something */
if (ftrace_trace_function == ftrace_stub)
return;
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
func = ftrace_trace_function;
#else
func = __ftrace_trace_function;
#endif
if (!list_empty(&ftrace_pids)) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
} else {
if (func == ftrace_pid_func)
func = ftrace_pid_function;
}
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
__ftrace_trace_function = func;
#endif
update_ftrace_function();
}
#ifdef CONFIG_FUNCTION_PROFILER
@ -1079,19 +1056,16 @@ static void ftrace_replace_code(int enable)
struct ftrace_page *pg;
int failed;
if (unlikely(ftrace_disabled))
return;
do_for_each_ftrace_rec(pg, rec) {
/*
* Skip over free records, records that have
* failed and not converted.
*/
if (rec->flags & FTRACE_FL_FREE ||
rec->flags & FTRACE_FL_FAILED ||
!(rec->flags & FTRACE_FL_CONVERTED))
/* Skip over free records */
if (rec->flags & FTRACE_FL_FREE)
continue;
failed = __ftrace_replace_code(rec, enable);
if (failed) {
rec->flags |= FTRACE_FL_FAILED;
ftrace_bug(failed, rec->ip);
/* Stop processing */
return;
@ -1107,10 +1081,12 @@ ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
ip = rec->ip;
if (unlikely(ftrace_disabled))
return 0;
ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
if (ret) {
ftrace_bug(ret, ip);
rec->flags |= FTRACE_FL_FAILED;
return 0;
}
return 1;
@ -1273,10 +1249,10 @@ static int ftrace_update_code(struct module *mod)
*/
if (!ftrace_code_disable(mod, p)) {
ftrace_free_rec(p);
continue;
/* Game over */
break;
}
p->flags |= FTRACE_FL_CONVERTED;
ftrace_update_cnt++;
/*
@ -1351,9 +1327,8 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
enum {
FTRACE_ITER_FILTER = (1 << 0),
FTRACE_ITER_NOTRACE = (1 << 1),
FTRACE_ITER_FAILURES = (1 << 2),
FTRACE_ITER_PRINTALL = (1 << 3),
FTRACE_ITER_HASH = (1 << 4),
FTRACE_ITER_PRINTALL = (1 << 2),
FTRACE_ITER_HASH = (1 << 3),
};
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
@ -1463,6 +1438,9 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
struct ftrace_iterator *iter = m->private;
struct dyn_ftrace *rec = NULL;
if (unlikely(ftrace_disabled))
return NULL;
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_next(m, pos);
@ -1483,12 +1461,6 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
rec = &iter->pg->records[iter->idx++];
if ((rec->flags & FTRACE_FL_FREE) ||
(!(iter->flags & FTRACE_ITER_FAILURES) &&
(rec->flags & FTRACE_FL_FAILED)) ||
((iter->flags & FTRACE_ITER_FAILURES) &&
!(rec->flags & FTRACE_FL_FAILED)) ||
((iter->flags & FTRACE_ITER_FILTER) &&
!(rec->flags & FTRACE_FL_FILTER)) ||
@ -1521,6 +1493,10 @@ static void *t_start(struct seq_file *m, loff_t *pos)
loff_t l;
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled))
return NULL;
/*
* If an lseek was done, then reset and start from beginning.
*/
@ -1629,24 +1605,6 @@ ftrace_avail_open(struct inode *inode, struct file *file)
return ret;
}
static int
ftrace_failures_open(struct inode *inode, struct file *file)
{
int ret;
struct seq_file *m;
struct ftrace_iterator *iter;
ret = ftrace_avail_open(inode, file);
if (!ret) {
m = file->private_data;
iter = m->private;
iter->flags = FTRACE_ITER_FAILURES;
}
return ret;
}
static void ftrace_filter_reset(int enable)
{
struct ftrace_page *pg;
@ -1657,8 +1615,6 @@ static void ftrace_filter_reset(int enable)
if (enable)
ftrace_filtered = 0;
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_FAILED)
continue;
rec->flags &= ~type;
} while_for_each_ftrace_rec();
mutex_unlock(&ftrace_lock);
@ -1760,42 +1716,63 @@ static int ftrace_match(char *str, char *regex, int len, int type)
return matched;
}
static void
update_record(struct dyn_ftrace *rec, unsigned long flag, int not)
{
if (not)
rec->flags &= ~flag;
else
rec->flags |= flag;
}
static int
ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
ftrace_match_record(struct dyn_ftrace *rec, char *mod,
char *regex, int len, int type)
{
char str[KSYM_SYMBOL_LEN];
char *modname;
kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
if (mod) {
/* module lookup requires matching the module */
if (!modname || strcmp(modname, mod))
return 0;
/* blank search means to match all funcs in the mod */
if (!len)
return 1;
}
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
return ftrace_match(str, regex, len, type);
}
static int ftrace_match_records(char *buff, int len, int enable)
static int match_records(char *buff, int len, char *mod, int enable, int not)
{
unsigned int search_len;
unsigned search_len = 0;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
int type = MATCH_FULL;
char *search = buff;
unsigned long flag;
char *search;
int type;
int not;
int found = 0;
flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
type = filter_parse_regex(buff, len, &search, &not);
if (len) {
type = filter_parse_regex(buff, len, &search, &not);
search_len = strlen(search);
}
search_len = strlen(search);
flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled))
goto out_unlock;
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_FAILED)
continue;
if (ftrace_match_record(rec, search, search_len, type)) {
if (not)
rec->flags &= ~flag;
else
rec->flags |= flag;
if (ftrace_match_record(rec, mod, search, search_len, type)) {
update_record(rec, flag, not);
found = 1;
}
/*
@ -1804,43 +1781,23 @@ static int ftrace_match_records(char *buff, int len, int enable)
*/
if (enable && (rec->flags & FTRACE_FL_FILTER))
ftrace_filtered = 1;
} while_for_each_ftrace_rec();
out_unlock:
mutex_unlock(&ftrace_lock);
return found;
}
static int
ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
char *regex, int len, int type)
ftrace_match_records(char *buff, int len, int enable)
{
char str[KSYM_SYMBOL_LEN];
char *modname;
kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
if (!modname || strcmp(modname, mod))
return 0;
/* blank search means to match all funcs in the mod */
if (len)
return ftrace_match(str, regex, len, type);
else
return 1;
return match_records(buff, len, NULL, enable, 0);
}
static int ftrace_match_module_records(char *buff, char *mod, int enable)
{
unsigned search_len = 0;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
int type = MATCH_FULL;
char *search = buff;
unsigned long flag;
int not = 0;
int found = 0;
flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
/* blank or '*' mean the same */
if (strcmp(buff, "*") == 0)
@ -1852,32 +1809,7 @@ static int ftrace_match_module_records(char *buff, char *mod, int enable)
not = 1;
}
if (strlen(buff)) {
type = filter_parse_regex(buff, strlen(buff), &search, &not);
search_len = strlen(search);
}
mutex_lock(&ftrace_lock);
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_FAILED)
continue;
if (ftrace_match_module_record(rec, mod,
search, search_len, type)) {
if (not)
rec->flags &= ~flag;
else
rec->flags |= flag;
found = 1;
}
if (enable && (rec->flags & FTRACE_FL_FILTER))
ftrace_filtered = 1;
} while_for_each_ftrace_rec();
mutex_unlock(&ftrace_lock);
return found;
return match_records(buff, strlen(buff), mod, enable, not);
}
/*
@ -2029,12 +1961,13 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
return -EINVAL;
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled))
goto out_unlock;
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & FTRACE_FL_FAILED)
continue;
if (!ftrace_match_record(rec, search, len, type))
if (!ftrace_match_record(rec, NULL, search, len, type))
continue;
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
@ -2239,6 +2172,10 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
mutex_lock(&ftrace_regex_lock);
ret = -ENODEV;
if (unlikely(ftrace_disabled))
goto out_unlock;
if (file->f_mode & FMODE_READ) {
struct seq_file *m = file->private_data;
iter = m->private;
@ -2446,13 +2383,6 @@ static const struct file_operations ftrace_avail_fops = {
.release = seq_release_private,
};
static const struct file_operations ftrace_failures_fops = {
.open = ftrace_failures_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static const struct file_operations ftrace_filter_fops = {
.open = ftrace_filter_open,
.read = seq_read,
@ -2575,9 +2505,6 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
bool exists;
int i;
if (ftrace_disabled)
return -ENODEV;
/* decode regex */
type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
@ -2586,12 +2513,18 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
search_len = strlen(search);
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled)) {
mutex_unlock(&ftrace_lock);
return -ENODEV;
}
do_for_each_ftrace_rec(pg, rec) {
if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
if (rec->flags & FTRACE_FL_FREE)
continue;
if (ftrace_match_record(rec, search, search_len, type)) {
if (ftrace_match_record(rec, NULL, search, search_len, type)) {
/* if it is in the array */
exists = false;
for (i = 0; i < *idx; i++) {
@ -2681,9 +2614,6 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
trace_create_file("available_filter_functions", 0444,
d_tracer, NULL, &ftrace_avail_fops);
trace_create_file("failures", 0444,
d_tracer, NULL, &ftrace_failures_fops);
trace_create_file("set_ftrace_filter", 0644, d_tracer,
NULL, &ftrace_filter_fops);
@ -2705,7 +2635,6 @@ static int ftrace_process_locs(struct module *mod,
{
unsigned long *p;
unsigned long addr;
unsigned long flags;
mutex_lock(&ftrace_lock);
p = start;
@ -2722,10 +2651,7 @@ static int ftrace_process_locs(struct module *mod,
ftrace_record_ip(addr);
}
/* disable interrupts to prevent kstop machine */
local_irq_save(flags);
ftrace_update_code(mod);
local_irq_restore(flags);
mutex_unlock(&ftrace_lock);
return 0;
@ -2737,10 +2663,11 @@ void ftrace_release_mod(struct module *mod)
struct dyn_ftrace *rec;
struct ftrace_page *pg;
if (ftrace_disabled)
return;
mutex_lock(&ftrace_lock);
if (ftrace_disabled)
goto out_unlock;
do_for_each_ftrace_rec(pg, rec) {
if (within_module_core(rec->ip, mod)) {
/*
@ -2751,6 +2678,7 @@ void ftrace_release_mod(struct module *mod)
ftrace_free_rec(rec);
}
} while_for_each_ftrace_rec();
out_unlock:
mutex_unlock(&ftrace_lock);
}
@ -3145,16 +3073,17 @@ void ftrace_kill(void)
*/
int register_ftrace_function(struct ftrace_ops *ops)
{
int ret;
if (unlikely(ftrace_disabled))
return -1;
int ret = -1;
mutex_lock(&ftrace_lock);
if (unlikely(ftrace_disabled))
goto out_unlock;
ret = __register_ftrace_function(ops);
ftrace_startup(0);
out_unlock:
mutex_unlock(&ftrace_lock);
return ret;
}
@ -3182,14 +3111,14 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
int ret;
if (unlikely(ftrace_disabled))
return -ENODEV;
int ret = -ENODEV;
mutex_lock(&ftrace_lock);
ret = proc_dointvec(table, write, buffer, lenp, ppos);
if (unlikely(ftrace_disabled))
goto out;
ret = proc_dointvec(table, write, buffer, lenp, ppos);
if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
goto out;