From 5500fa51199aee770ce53718853732600543619e Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 15 Feb 2012 15:51:54 +0100 Subject: [PATCH] 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: Jiri Olsa Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 7 +- kernel/trace/ftrace.c | 6 ++ kernel/trace/trace.h | 2 - kernel/trace/trace_event_perf.c | 4 +- kernel/trace/trace_events_filter.c | 165 +++++++++++++++++++++++++++-- 5 files changed, 172 insertions(+), 12 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 64a309d2fbd6..72a6cabb4d5b 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -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; } diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index f615f974d90e..867bd1dd2dd0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -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; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 29f93cd434a5..54faec790bc1 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -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; diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index fdeeb5c49627..fee3752ae8f6 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -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) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 3da3d0ec3584..431dba8b7542 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -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: -- GitLab