xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

trace_uprobe: support reference counter in fd-based uprobe

Browse Source 
This patch enables uprobes with reference counter in fd-based uprobe.
Highest 32 bits of perf_event_attr.config is used to stored offset
of the reference count (semaphore).

Format information in /sys/bus/event_source/devices/uprobe/format/ is
updated to reflect this new feature.

Link: http://lkml.kernel.org/r/20181002053636.1896903-1-songliubraving@fb.com

Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-and-tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Song Liu
2018-10-01 22:36:36 -07:00
committed by Steven Rostedt (VMware)
parent 5a5e3d3cea
commit a6ca88b241
5 changed files with 50 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

49
kernel/events/core.c
View File

@@ -8368,30 +8368,39 @@ static struct pmu perf_tracepoint = {
*
* PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
* if not set, create kprobe/uprobe
*
* The following values specify a reference counter (or semaphore in the
* terminology of tools like dtrace, systemtap, etc.) Userspace Statically
* Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
*
* PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
* PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
*/
enum perf_probe_config {
PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
};
PMU_FORMAT_ATTR(retprobe, "config:0");
#endif
static struct attribute *probe_attrs[] = {
#ifdef CONFIG_KPROBE_EVENTS
static struct attribute *kprobe_attrs[] = {
&format_attr_retprobe.attr,
NULL,
};
static struct attribute_group probe_format_group = {
static struct attribute_group kprobe_format_group = {
.name = "format",
.attrs = probe_attrs,
.attrs = kprobe_attrs,
};
static const struct attribute_group *probe_attr_groups[] = {
&probe_format_group,
static const struct attribute_group *kprobe_attr_groups[] = {
&kprobe_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,
@@ -8401,7 +8410,7 @@ static struct pmu perf_kprobe = {
.start = perf_swevent_start,
.stop = perf_swevent_stop,
.read = perf_swevent_read,
.attr_groups = probe_attr_groups,
.attr_groups = kprobe_attr_groups,
};
static int perf_kprobe_event_init(struct perf_event *event)
@@ -8433,6 +8442,24 @@ static int perf_kprobe_event_init(struct perf_event *event)
#endif /* CONFIG_KPROBE_EVENTS */
#ifdef CONFIG_UPROBE_EVENTS
PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
static struct attribute *uprobe_attrs[] = {
&format_attr_retprobe.attr,
&format_attr_ref_ctr_offset.attr,
NULL,
};
static struct attribute_group uprobe_format_group = {
.name = "format",
.attrs = uprobe_attrs,
};
static const struct attribute_group *uprobe_attr_groups[] = {
&uprobe_format_group,
NULL,
};
static int perf_uprobe_event_init(struct perf_event *event);
static struct pmu perf_uprobe = {
.task_ctx_nr = perf_sw_context,
@@ -8442,12 +8469,13 @@ static struct pmu perf_uprobe = {
.start = perf_swevent_start,
.stop = perf_swevent_stop,
.read = perf_swevent_read,
.attr_groups = probe_attr_groups,
.attr_groups = uprobe_attr_groups,
};
static int perf_uprobe_event_init(struct perf_event *event)
{
int err;
unsigned long ref_ctr_offset;
bool is_retprobe;
if (event->attr.type != perf_uprobe.type)
@@ -8463,7 +8491,8 @@ static int perf_uprobe_event_init(struct perf_event *event)
return -EOPNOTSUPP;
is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
err = perf_uprobe_init(event, is_retprobe);
ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
if (err)
return err;