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perf/core: Implement the 'perf_uprobe' PMU 

This patch adds perf_uprobe support with similar pattern as previous
patch (for kprobe).

Two functions, create_local_trace_uprobe() and
destroy_local_trace_uprobe(), are created so a uprobe can be created
and attached to the file descriptor created by perf_event_open().

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/20171206224518.3598254-7-songliubraving@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Song Liu 2017-12-06 14:45:16 -08:00 committed by Ingo Molnar
parent e12f03d703
commit 33ea4b2427
5 changed files with 186 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/trace_events.h
View File

@ -537,6 +537,10 @@ extern void perf_trace_del(struct perf_event *event, int flags);
extern int perf_kprobe_init(struct perf_event *event, bool is_retprobe);
extern void perf_kprobe_destroy(struct perf_event *event);
#endif
#ifdef CONFIG_UPROBE_EVENTS
extern int perf_uprobe_init(struct perf_event *event, bool is_retprobe);
extern void perf_uprobe_destroy(struct perf_event *event);
#endif
extern int ftrace_profile_set_filter(struct perf_event *event, int event_id,
char *filter_str);
extern void ftrace_profile_free_filter(struct perf_event *event);

48
kernel/events/core.c
View File

@ -7992,7 +7992,7 @@ static struct pmu perf_tracepoint = {
.read = perf_swevent_read,
};
#ifdef CONFIG_KPROBE_EVENTS
#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
/*
* Flags in config, used by dynamic PMU kprobe and uprobe
* The flags should match following PMU_FORMAT_ATTR().
@ -8020,7 +8020,9 @@ static const struct attribute_group *probe_attr_groups[] = {
&probe_format_group,
NULL,
};
#endif
#ifdef CONFIG_KPROBE_EVENTS
static int perf_kprobe_event_init(struct perf_event *event);
static struct pmu perf_kprobe = {
.task_ctx_nr = perf_sw_context,
@ -8057,12 +8059,52 @@ static int perf_kprobe_event_init(struct perf_event *event)
}
#endif /* CONFIG_KPROBE_EVENTS */
#ifdef CONFIG_UPROBE_EVENTS
static int perf_uprobe_event_init(struct perf_event *event);
static struct pmu perf_uprobe = {
.task_ctx_nr = perf_sw_context,
.event_init = perf_uprobe_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_uprobe_event_init(struct perf_event *event)
{
int err;
bool is_retprobe;
if (event->attr.type != perf_uprobe.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_uprobe_init(event, is_retprobe);
if (err)
return err;
event->destroy = perf_uprobe_destroy;
return 0;
}
#endif /* CONFIG_UPROBE_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
#ifdef CONFIG_UPROBE_EVENTS
perf_pmu_register(&perf_uprobe, "uprobe", -1);
#endif
}
static void perf_event_free_filter(struct perf_event *event)
@ -8150,6 +8192,10 @@ static inline bool perf_event_is_tracing(struct perf_event *event)
#ifdef CONFIG_KPROBE_EVENTS
if (event->pmu == &perf_kprobe)
return true;
#endif
#ifdef CONFIG_UPROBE_EVENTS
if (event->pmu == &perf_uprobe)
return true;
#endif
return false;
}

53
kernel/trace/trace_event_perf.c
View File

@ -286,6 +286,59 @@ void perf_kprobe_destroy(struct perf_event *p_event)
}
#endif /* CONFIG_KPROBE_EVENTS */
#ifdef CONFIG_UPROBE_EVENTS
int perf_uprobe_init(struct perf_event *p_event, bool is_retprobe)
{
int ret;
char *path = NULL;
struct trace_event_call *tp_event;
if (!p_event->attr.uprobe_path)
return -EINVAL;
path = kzalloc(PATH_MAX, GFP_KERNEL);
if (!path)
return -ENOMEM;
ret = strncpy_from_user(
path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX);
if (ret < 0)
goto out;
if (path[0] == '\0') {
ret = -EINVAL;
goto out;
}
tp_event = create_local_trace_uprobe(
path, p_event->attr.probe_offset, is_retprobe);
if (IS_ERR(tp_event)) {
ret = PTR_ERR(tp_event);
goto out;
}
/*
* local trace_uprobe need to hold event_mutex to call
* uprobe_buffer_enable() and uprobe_buffer_disable().
* event_mutex is not required for local trace_kprobes.
*/
mutex_lock(&event_mutex);
ret = perf_trace_event_init(tp_event, p_event);
if (ret)
destroy_local_trace_uprobe(tp_event);
mutex_unlock(&event_mutex);
out:
kfree(path);
return ret;
}
void perf_uprobe_destroy(struct perf_event *p_event)
{
mutex_lock(&event_mutex);
perf_trace_event_close(p_event);
perf_trace_event_unreg(p_event);
mutex_unlock(&event_mutex);
destroy_local_trace_uprobe(p_event->tp_event);
}
#endif /* CONFIG_UPROBE_EVENTS */
int perf_trace_add(struct perf_event *p_event, int flags)
{
struct trace_event_call *tp_event = p_event->tp_event;

4
kernel/trace/trace_probe.h
View File

@ -410,4 +410,8 @@ extern struct trace_event_call *
create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
bool is_return);
extern void destroy_local_trace_kprobe(struct trace_event_call *event_call);
extern struct trace_event_call *
create_local_trace_uprobe(char *name, unsigned long offs, bool is_return);
extern void destroy_local_trace_uprobe(struct trace_event_call *event_call);
#endif

86
kernel/trace/trace_uprobe.c
View File

@ -1292,16 +1292,25 @@ static struct trace_event_functions uprobe_funcs = {
.trace = print_uprobe_event
};
static int register_uprobe_event(struct trace_uprobe *tu)
static inline void init_trace_event_call(struct trace_uprobe *tu,
struct trace_event_call *call)
{
struct trace_event_call *call = &tu->tp.call;
int ret;
/* Initialize trace_event_call */
INIT_LIST_HEAD(&call->class->fields);
call->event.funcs = &uprobe_funcs;
call->class->define_fields = uprobe_event_define_fields;
call->flags = TRACE_EVENT_FL_UPROBE;
call->class->reg = trace_uprobe_register;
call->data = tu;
}
static int register_uprobe_event(struct trace_uprobe *tu)
{
struct trace_event_call *call = &tu->tp.call;
int ret = 0;
init_trace_event_call(tu, call);
if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
return -ENOMEM;
@ -1311,9 +1320,6 @@ static int register_uprobe_event(struct trace_uprobe *tu)
return -ENODEV;
}
call->flags = TRACE_EVENT_FL_UPROBE;
call->class->reg = trace_uprobe_register;
call->data = tu;
ret = trace_add_event_call(call);
if (ret) {
@ -1339,6 +1345,70 @@ static int unregister_uprobe_event(struct trace_uprobe *tu)
return 0;
}
#ifdef CONFIG_PERF_EVENTS
struct trace_event_call *
create_local_trace_uprobe(char *name, unsigned long offs, bool is_return)
{
struct trace_uprobe *tu;
struct inode *inode;
struct path path;
int ret;
ret = kern_path(name, LOOKUP_FOLLOW, &path);
if (ret)
return ERR_PTR(ret);
inode = igrab(d_inode(path.dentry));
path_put(&path);
if (!inode || !S_ISREG(inode->i_mode)) {
iput(inode);
return ERR_PTR(-EINVAL);
}
/*
* local trace_kprobes are not added to probe_list, so they are never
* searched in find_trace_kprobe(). Therefore, there is no concern of
* duplicated name "DUMMY_EVENT" here.
*/
tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
is_return);
if (IS_ERR(tu)) {
pr_info("Failed to allocate trace_uprobe.(%d)\n",
(int)PTR_ERR(tu));
return ERR_CAST(tu);
}
tu->offset = offs;
tu->inode = inode;
tu->filename = kstrdup(name, GFP_KERNEL);
init_trace_event_call(tu, &tu->tp.call);
if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
ret = -ENOMEM;
goto error;
}
return &tu->tp.call;
error:
free_trace_uprobe(tu);
return ERR_PTR(ret);
}
void destroy_local_trace_uprobe(struct trace_event_call *event_call)
{
struct trace_uprobe *tu;
tu = container_of(event_call, struct trace_uprobe, tp.call);
kfree(tu->tp.call.print_fmt);
tu->tp.call.print_fmt = NULL;
free_trace_uprobe(tu);
}
#endif /* CONFIG_PERF_EVENTS */
/* Make a trace interface for controling probe points */
static __init int init_uprobe_trace(void)
{