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perf/x86/intel/pt: Use bitwise access for PERF_HES_STOPPED

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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
This commit is contained in:
Adrian Hunter 2026-07-21 10:02:53 +03:00 committed by Peter Zijlstra
parent c6df517796
commit 265bb4ef75
1 changed files with 8 additions and 8 deletions
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16
arch/x86/events/intel/pt.c
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@ -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;