Commit 5500fa51 authored by Jiri Olsa's avatar Jiri Olsa Committed by Steven Rostedt
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ftrace, perf: Add filter support for function trace event

Adding support to filter function trace event via perf
interface. It is now possible to use filter interface
in the perf tool like:

  perf record -e ftrace:function --filter="(ip == mm_*)" ls

The filter syntax is restricted to the the 'ip' field only,
and following operators are accepted '==' '!=' '||', ending
up with the filter strings like:

  ip == f1[, ]f2 ... || ip != f3[, ]f4 ...

with comma ',' or space ' ' as a function separator. If the
space ' ' is used as a separator, the right side of the
assignment needs to be enclosed in double quotes '"', e.g.:

  perf record -e ftrace:function --filter '(ip == do_execve,sys_*,ext*)' ls
  perf record -e ftrace:function --filter '(ip == "do_execve,sys_*,ext*")' ls
  perf record -e ftrace:function --filter '(ip == "do_execve sys_* ext*")' ls

The '==' operator adds trace filter with same effect as would
be added via set_ftrace_filter file.

The '!=' operator adds trace filter with same effect as would
be added via set_ftrace_notrace file.

The right side of the '!=', '==' operators is list of functions
or regexp. to be added to filter separated by space.

The '||' operator is used for connecting multiple filter definitions
together. It is possible to have more than one '==' and '!='
operators within one filter string.

Link: http://lkml.kernel.org/r/1329317514-8131-8-git-send-email-jolsa@redhat.com

Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 02aa3162
......@@ -250,6 +250,7 @@ int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
int len, int reset);
void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
void ftrace_free_filter(struct ftrace_ops *ops);
int register_ftrace_command(struct ftrace_func_command *cmd);
int unregister_ftrace_command(struct ftrace_func_command *cmd);
......@@ -380,9 +381,6 @@ extern void ftrace_enable_daemon(void);
#else
static inline int skip_trace(unsigned long ip) { return 0; }
static inline int ftrace_force_update(void) { return 0; }
static inline void ftrace_set_filter(unsigned char *buf, int len, int reset)
{
}
static inline void ftrace_disable_daemon(void) { }
static inline void ftrace_enable_daemon(void) { }
static inline void ftrace_release_mod(struct module *mod) {}
......@@ -406,6 +404,9 @@ static inline int ftrace_text_reserved(void *start, void *end)
*/
#define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
#define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
#define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
#define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
#define ftrace_free_filter(ops) do { } while (0)
static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos) { return -ENODEV; }
......
......@@ -1186,6 +1186,12 @@ static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
}
void ftrace_free_filter(struct ftrace_ops *ops)
{
free_ftrace_hash(ops->filter_hash);
free_ftrace_hash(ops->notrace_hash);
}
static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
{
struct ftrace_hash *hash;
......
......@@ -776,9 +776,7 @@ struct filter_pred {
u64 val;
struct regex regex;
unsigned short *ops;
#ifdef CONFIG_FTRACE_STARTUP_TEST
struct ftrace_event_field *field;
#endif
int offset;
int not;
int op;
......
......@@ -298,7 +298,9 @@ static int perf_ftrace_function_register(struct perf_event *event)
static int perf_ftrace_function_unregister(struct perf_event *event)
{
struct ftrace_ops *ops = &event->ftrace_ops;
return unregister_ftrace_function(ops);
int ret = unregister_ftrace_function(ops);
ftrace_free_filter(ops);
return ret;
}
static void perf_ftrace_function_enable(struct perf_event *event)
......
......@@ -81,6 +81,7 @@ enum {
FILT_ERR_TOO_MANY_PREDS,
FILT_ERR_MISSING_FIELD,
FILT_ERR_INVALID_FILTER,
FILT_ERR_IP_FIELD_ONLY,
};
static char *err_text[] = {
......@@ -96,6 +97,7 @@ static char *err_text[] = {
"Too many terms in predicate expression",
"Missing field name and/or value",
"Meaningless filter expression",
"Only 'ip' field is supported for function trace",
};
struct opstack_op {
......@@ -991,7 +993,12 @@ static int init_pred(struct filter_parse_state *ps,
fn = filter_pred_strloc;
else
fn = filter_pred_pchar;
} else if (!is_function_field(field)) {
} else if (is_function_field(field)) {
if (strcmp(field->name, "ip")) {
parse_error(ps, FILT_ERR_IP_FIELD_ONLY, 0);
return -EINVAL;
}
} else {
if (field->is_signed)
ret = strict_strtoll(pred->regex.pattern, 0, &val);
else
......@@ -1338,10 +1345,7 @@ static struct filter_pred *create_pred(struct filter_parse_state *ps,
strcpy(pred.regex.pattern, operand2);
pred.regex.len = strlen(pred.regex.pattern);
#ifdef CONFIG_FTRACE_STARTUP_TEST
pred.field = field;
#endif
return init_pred(ps, field, &pred) ? NULL : &pred;
}
......@@ -1954,6 +1958,148 @@ void ftrace_profile_free_filter(struct perf_event *event)
__free_filter(filter);
}
struct function_filter_data {
struct ftrace_ops *ops;
int first_filter;
int first_notrace;
};
#ifdef CONFIG_FUNCTION_TRACER
static char **
ftrace_function_filter_re(char *buf, int len, int *count)
{
char *str, *sep, **re;
str = kstrndup(buf, len, GFP_KERNEL);
if (!str)
return NULL;
/*
* The argv_split function takes white space
* as a separator, so convert ',' into spaces.
*/
while ((sep = strchr(str, ',')))
*sep = ' ';
re = argv_split(GFP_KERNEL, str, count);
kfree(str);
return re;
}
static int ftrace_function_set_regexp(struct ftrace_ops *ops, int filter,
int reset, char *re, int len)
{
int ret;
if (filter)
ret = ftrace_set_filter(ops, re, len, reset);
else
ret = ftrace_set_notrace(ops, re, len, reset);
return ret;
}
static int __ftrace_function_set_filter(int filter, char *buf, int len,
struct function_filter_data *data)
{
int i, re_cnt, ret;
int *reset;
char **re;
reset = filter ? &data->first_filter : &data->first_notrace;
/*
* The 'ip' field could have multiple filters set, separated
* either by space or comma. We first cut the filter and apply
* all pieces separatelly.
*/
re = ftrace_function_filter_re(buf, len, &re_cnt);
if (!re)
return -EINVAL;
for (i = 0; i < re_cnt; i++) {
ret = ftrace_function_set_regexp(data->ops, filter, *reset,
re[i], strlen(re[i]));
if (ret)
break;
if (*reset)
*reset = 0;
}
argv_free(re);
return ret;
}
static int ftrace_function_check_pred(struct filter_pred *pred, int leaf)
{
struct ftrace_event_field *field = pred->field;
if (leaf) {
/*
* Check the leaf predicate for function trace, verify:
* - only '==' and '!=' is used
* - the 'ip' field is used
*/
if ((pred->op != OP_EQ) && (pred->op != OP_NE))
return -EINVAL;
if (strcmp(field->name, "ip"))
return -EINVAL;
} else {
/*
* Check the non leaf predicate for function trace, verify:
* - only '||' is used
*/
if (pred->op != OP_OR)
return -EINVAL;
}
return 0;
}
static int ftrace_function_set_filter_cb(enum move_type move,
struct filter_pred *pred,
int *err, void *data)
{
/* Checking the node is valid for function trace. */
if ((move != MOVE_DOWN) ||
(pred->left != FILTER_PRED_INVALID)) {
*err = ftrace_function_check_pred(pred, 0);
} else {
*err = ftrace_function_check_pred(pred, 1);
if (*err)
return WALK_PRED_ABORT;
*err = __ftrace_function_set_filter(pred->op == OP_EQ,
pred->regex.pattern,
pred->regex.len,
data);
}
return (*err) ? WALK_PRED_ABORT : WALK_PRED_DEFAULT;
}
static int ftrace_function_set_filter(struct perf_event *event,
struct event_filter *filter)
{
struct function_filter_data data = {
.first_filter = 1,
.first_notrace = 1,
.ops = &event->ftrace_ops,
};
return walk_pred_tree(filter->preds, filter->root,
ftrace_function_set_filter_cb, &data);
}
#else
static int ftrace_function_set_filter(struct perf_event *event,
struct event_filter *filter)
{
return -ENODEV;
}
#endif /* CONFIG_FUNCTION_TRACER */
int ftrace_profile_set_filter(struct perf_event *event, int event_id,
char *filter_str)
{
......@@ -1974,9 +2120,16 @@ int ftrace_profile_set_filter(struct perf_event *event, int event_id,
goto out_unlock;
err = create_filter(call, filter_str, false, &filter);
if (!err)
event->filter = filter;
if (err)
goto free_filter;
if (ftrace_event_is_function(call))
err = ftrace_function_set_filter(event, filter);
else
event->filter = filter;
free_filter:
if (err || ftrace_event_is_function(call))
__free_filter(filter);
out_unlock:
......
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