Commit 0c2822b1 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux 

Pull arm64 regression fix from Will Deacon:
 "Apologies for the _extremely_ late pull request here, but we had a
  'perf' (i.e. CPU PMU) regression on the Apple M1 reported on Wednesday
  [1] which was introduced by bd275681 ("perf: Rewrite core context
  handling") during the merge window.

  Mark and I looked into this and noticed an additional problem caused
  by the same patch, where the 'CHAIN' event (used to combine two
  adjacent 32-bit counters into a single 64-bit counter) was not being
  filtered correctly. Mark posted a series on Thursday [2] which
  addresses both of these regressions and I queued it the same day.

  The changes are small, self-contained and have been confirmed to fix
  the original regression.

  Summary:

   - Fix 'perf' regression for non-standard CPU PMU hardware (i.e. Apple
     M1)"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: perf: reject CHAIN events at creation time
  arm_pmu: fix event CPU filtering
parents 0e9fd589 853e2dac

arch/arm64/kernel/perf_event.c

+8 −7
Original line number Diff line number Diff line
@@ -1023,12 +1023,6 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event, 
	return 0;

}



static bool armv8pmu_filter(struct pmu *pmu, int cpu)

{

	struct arm_pmu *armpmu = to_arm_pmu(pmu);

	return !cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus);

}



static void armv8pmu_reset(void *info)

{

	struct arm_pmu *cpu_pmu = (struct arm_pmu *)info;
@@ -1069,6 +1063,14 @@ static int __armv8_pmuv3_map_event(struct perf_event *event, 
				       &armv8_pmuv3_perf_cache_map,

				       ARMV8_PMU_EVTYPE_EVENT);



	/*

	 * CHAIN events only work when paired with an adjacent counter, and it

	 * never makes sense for a user to open one in isolation, as they'll be

	 * rotated arbitrarily.

	 */

	if (hw_event_id == ARMV8_PMUV3_PERFCTR_CHAIN)

		return -EINVAL;



	if (armv8pmu_event_is_64bit(event))

		event->hw.flags |= ARMPMU_EVT_64BIT;
@@ -1258,7 +1260,6 @@ static int armv8_pmu_init(struct arm_pmu *cpu_pmu, char *name, 
	cpu_pmu->stop			= armv8pmu_stop;

	cpu_pmu->reset			= armv8pmu_reset;

	cpu_pmu->set_event_filter	= armv8pmu_set_event_filter;

	cpu_pmu->filter			= armv8pmu_filter;



	cpu_pmu->pmu.event_idx		= armv8pmu_user_event_idx;

drivers/perf/arm_pmu.c

+1 −7
Original line number Diff line number Diff line
@@ -550,13 +550,7 @@ static void armpmu_disable(struct pmu *pmu) 
static bool armpmu_filter(struct pmu *pmu, int cpu)

{

	struct arm_pmu *armpmu = to_arm_pmu(pmu);

	bool ret;



	ret = cpumask_test_cpu(cpu, &armpmu->supported_cpus);

	if (ret && armpmu->filter)

		return armpmu->filter(pmu, cpu);



	return ret;

	return !cpumask_test_cpu(cpu, &armpmu->supported_cpus);

}



static ssize_t cpus_show(struct device *dev,

include/linux/perf/arm_pmu.h

+0 −1
Original line number Diff line number Diff line
@@ -100,7 +100,6 @@ struct arm_pmu { 
	void		(*stop)(struct arm_pmu *);

	void		(*reset)(void *);

	int		(*map_event)(struct perf_event *event);

	bool		(*filter)(struct pmu *pmu, int cpu);

	int		num_events;

	bool		secure_access; /* 32-bit ARM only */

#define ARMV8_PMUV3_MAX_COMMON_EVENTS		0x40