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perf/core: Implement the 'perf_kprobe' PMU

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A new PMU type, perf_kprobe is added. Based on attr from perf_event_open(),
perf_kprobe creates a kprobe (or kretprobe) for the perf_event. This
kprobe is private to this perf_event, and thus not added to global
lists, and not available in tracefs.

Two functions, create_local_trace_kprobe() and
destroy_local_trace_kprobe()  are added to created and destroy these
local trace_kprobe.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Yonghong Song <yhs@fb.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Cc: <daniel@iogearbox.net>
Cc: <davem@davemloft.net>
Cc: <kernel-team@fb.com>
Cc: <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171206224518.3598254-6-songliubraving@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Song Liu
2017-12-06 14:45:15 -08:00
committed by Ingo Molnar
parent 0d8dd67be0
commit e12f03d703
5 changed files with 250 additions and 43 deletions
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142
kernel/events/core.c
View File

@@ -7992,9 +7992,77 @@ static struct pmu perf_tracepoint = {
.read = perf_swevent_read,
};
#ifdef CONFIG_KPROBE_EVENTS
/*
* Flags in config, used by dynamic PMU kprobe and uprobe
* The flags should match following PMU_FORMAT_ATTR().
*
* PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
* if not set, create kprobe/uprobe
*/
enum perf_probe_config {
PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
};
PMU_FORMAT_ATTR(retprobe, "config:0");
static struct attribute *probe_attrs[] = {
&format_attr_retprobe.attr,
NULL,
};
static struct attribute_group probe_format_group = {
.name = "format",
.attrs = probe_attrs,
};
static const struct attribute_group *probe_attr_groups[] = {
&probe_format_group,
NULL,
};
static int perf_kprobe_event_init(struct perf_event *event);
static struct pmu perf_kprobe = {
.task_ctx_nr = perf_sw_context,
.event_init = perf_kprobe_event_init,
.add = perf_trace_add,
.del = perf_trace_del,
.start = perf_swevent_start,
.stop = perf_swevent_stop,
.read = perf_swevent_read,
.attr_groups = probe_attr_groups,
};
static int perf_kprobe_event_init(struct perf_event *event)
{
int err;
bool is_retprobe;
if (event->attr.type != perf_kprobe.type)
return -ENOENT;
/*
* no branch sampling for probe events
*/
if (has_branch_stack(event))
return -EOPNOTSUPP;
is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
err = perf_kprobe_init(event, is_retprobe);
if (err)
return err;
event->destroy = perf_kprobe_destroy;
return 0;
}
#endif /* CONFIG_KPROBE_EVENTS */
static inline void perf_tp_register(void)
{
perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
#ifdef CONFIG_KPROBE_EVENTS
perf_pmu_register(&perf_kprobe, "kprobe", -1);
#endif
}
static void perf_event_free_filter(struct perf_event *event)
@@ -8071,13 +8139,28 @@ static void perf_event_free_bpf_handler(struct perf_event *event)
}
#endif
/*
* returns true if the event is a tracepoint, or a kprobe/upprobe created
* with perf_event_open()
*/
static inline bool perf_event_is_tracing(struct perf_event *event)
{
if (event->pmu == &perf_tracepoint)
return true;
#ifdef CONFIG_KPROBE_EVENTS
if (event->pmu == &perf_kprobe)
return true;
#endif
return false;
}
static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
{
bool is_kprobe, is_tracepoint, is_syscall_tp;
struct bpf_prog *prog;
int ret;
if (event->attr.type != PERF_TYPE_TRACEPOINT)
if (!perf_event_is_tracing(event))
return perf_event_set_bpf_handler(event, prog_fd);
is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
@@ -8116,7 +8199,7 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
static void perf_event_free_bpf_prog(struct perf_event *event)
{
if (event->attr.type != PERF_TYPE_TRACEPOINT) {
if (!perf_event_is_tracing(event)) {
perf_event_free_bpf_handler(event);
return;
}
@@ -8535,47 +8618,36 @@ fail_clear_files:
return ret;
}
static int
perf_tracepoint_set_filter(struct perf_event *event, char *filter_str)
{
struct perf_event_context *ctx = event->ctx;
int ret;
/*
* Beware, here be dragons!!
*
* the tracepoint muck will deadlock against ctx->mutex, but the tracepoint
* stuff does not actually need it. So temporarily drop ctx->mutex. As per
* perf_event_ctx_lock() we already have a reference on ctx.
*
* This can result in event getting moved to a different ctx, but that
* does not affect the tracepoint state.
*/
mutex_unlock(&ctx->mutex);
ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
mutex_lock(&ctx->mutex);
return ret;
}
static int perf_event_set_filter(struct perf_event *event, void __user *arg)
{
char *filter_str;
int ret = -EINVAL;
if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
!IS_ENABLED(CONFIG_EVENT_TRACING)) &&
!has_addr_filter(event))
return -EINVAL;
char *filter_str;
filter_str = strndup_user(arg, PAGE_SIZE);
if (IS_ERR(filter_str))
return PTR_ERR(filter_str);
if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
event->attr.type == PERF_TYPE_TRACEPOINT)
ret = perf_tracepoint_set_filter(event, filter_str);
else if (has_addr_filter(event))
#ifdef CONFIG_EVENT_TRACING
if (perf_event_is_tracing(event)) {
struct perf_event_context *ctx = event->ctx;
/*
* Beware, here be dragons!!
*
* the tracepoint muck will deadlock against ctx->mutex, but
* the tracepoint stuff does not actually need it. So
* temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
* already have a reference on ctx.
*
* This can result in event getting moved to a different ctx,
* but that does not affect the tracepoint state.
*/
mutex_unlock(&ctx->mutex);
ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
mutex_lock(&ctx->mutex);
} else
#endif
if (has_addr_filter(event))
ret = perf_event_set_addr_filter(event, filter_str);
kfree(filter_str);