diff options
| author | Adrian Hunter <adrian.hunter@intel.com> | 2026-07-21 10:02:53 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-08-07 18:27:06 +0200 |
| commit | 265bb4ef75fa657f4957d72087a6a246b89d5f0d (patch) | |
| tree | 3074f43c8137fcc429c2b18dc3ec1e774d4d4c41 | |
| parent | c6df517796189723ffbdd7679206c97d3642c2ef (diff) | |
perf/x86/intel/pt: Use bitwise access for PERF_HES_STOPPED
The Intel PT driver reads and writes event->hw.state as a whole value,
assuming it is either 0 or PERF_HES_STOPPED. That is true today, but a
subsequent fix needs to also track an open AUX output buffer using the
PERF_HES_UPTODATE bit of the same field.
When more than one bit can be set, whole-value assignments would
overwrite the other bits and whole-value comparisons would fail to match.
Convert all accesses to set, clear and test the PERF_HES_STOPPED bit
individually, in preparation for that change.
No functional change intended: event->hw.state currently only ever
holds 0 or PERF_HES_STOPPED, so the bitwise forms are equivalent.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Yi Lai <yi1.lai@intel.com>
Link: https://patch.msgid.link/20260721070254.13557-3-adrian.hunter@intel.com
| -rw-r--r-- | arch/x86/events/intel/pt.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c index dc1be7f6e04b..2163e5ccdc04 100644 --- a/arch/x86/events/intel/pt.c +++ b/arch/x86/events/intel/pt.c @@ -1540,12 +1540,12 @@ void intel_pt_interrupt(void) perf_aux_output_end(&pt->handle, local_xchg(&buf->data_size, 0)); - if (!event->hw.state) { + if (!(event->hw.state & PERF_HES_STOPPED)) { int ret; buf = perf_aux_output_begin(&pt->handle, event); if (!buf) { - event->hw.state = PERF_HES_STOPPED; + event->hw.state |= PERF_HES_STOPPED; WRITE_ONCE(pt->resume_allowed, 0); return; } @@ -1639,7 +1639,7 @@ static void pt_event_start(struct perf_event *event, int mode) goto fail_end_stop; } - hwc->state = 0; + hwc->state &= ~PERF_HES_STOPPED; pt_config_buffer(buf); pt_config(event); @@ -1649,7 +1649,7 @@ static void pt_event_start(struct perf_event *event, int mode) fail_end_stop: perf_aux_output_end(&pt->handle, 0); fail_stop: - hwc->state = PERF_HES_STOPPED; + hwc->state |= PERF_HES_STOPPED; } static void pt_event_stop(struct perf_event *event, int mode) @@ -1680,10 +1680,10 @@ static void pt_event_stop(struct perf_event *event, int mode) pt_config_stop(event); - if (event->hw.state == PERF_HES_STOPPED) + if (event->hw.state & PERF_HES_STOPPED) return; - event->hw.state = PERF_HES_STOPPED; + event->hw.state |= PERF_HES_STOPPED; if (mode & PERF_EF_UPDATE) { struct pt_buffer *buf = perf_get_aux(&pt->handle); @@ -1778,10 +1778,10 @@ static int pt_event_add(struct perf_event *event, int mode) if (mode & PERF_EF_START) { pt_event_start(event, 0); ret = -EINVAL; - if (hwc->state == PERF_HES_STOPPED) + if (hwc->state & PERF_HES_STOPPED) goto fail; } else { - hwc->state = PERF_HES_STOPPED; + hwc->state |= PERF_HES_STOPPED; } ret = 0; |