Messages in this thread | | | From | Namhyung Kim <> | Date | Fri, 23 Jun 2023 16:21:12 -0700 | Subject | Re: [PATCH V13 03/10] arm64/perf: Add branch stack support in struct arm_pmu |
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Hello,
On Wed, Jun 21, 2023 at 11:55 PM Anshuman Khandual <anshuman.khandual@arm.com> wrote: > > This updates 'struct arm_pmu' for branch stack sampling support being added > later. This adds an element 'reg_trbidr' to capture BRBE attribute details.
reg_brbidr, right?
Thanks, Namhyung
> These updates here will help in tracking any branch stack sampling support. > > This also enables perf branch stack sampling event on all 'struct arm pmu', > supporting the feature but after removing the current gate that blocks such > events unconditionally in armpmu_event_init(). Instead a quick probe can be > initiated via arm_pmu->has_branch_stack to ascertain the support. > > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Tested-by: James Clark <james.clark@arm.com> > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > --- > drivers/perf/arm_pmu.c | 3 +-- > include/linux/perf/arm_pmu.h | 9 ++++++++- > 2 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c > index aada47e3b126..d9ffe9e56e74 100644 > --- a/drivers/perf/arm_pmu.c > +++ b/drivers/perf/arm_pmu.c > @@ -510,8 +510,7 @@ static int armpmu_event_init(struct perf_event *event) > !cpumask_test_cpu(event->cpu, &armpmu->supported_cpus)) > return -ENOENT; > > - /* does not support taken branch sampling */ > - if (has_branch_stack(event)) > + if (has_branch_stack(event) && !armpmu->has_branch_stack) > return -EOPNOTSUPP; > > return __hw_perf_event_init(event); > diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h > index f7fbd162ca4c..ba4204bdcebf 100644 > --- a/include/linux/perf/arm_pmu.h > +++ b/include/linux/perf/arm_pmu.h > @@ -102,7 +102,9 @@ struct arm_pmu { > int (*map_event)(struct perf_event *event); > void (*sched_task)(struct perf_event_pmu_context *pmu_ctx, bool sched_in); > int num_events; > - bool secure_access; /* 32-bit ARM only */ > + unsigned int secure_access : 1, /* 32-bit ARM only */ > + has_branch_stack: 1, /* 64-bit ARM only */ > + reserved : 30; > #define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40 > DECLARE_BITMAP(pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS); > #define ARMV8_PMUV3_EXT_COMMON_EVENT_BASE 0x4000 > @@ -118,6 +120,11 @@ struct arm_pmu { > > /* Only to be used by ACPI probing code */ > unsigned long acpi_cpuid; > + > + /* Implementation specific attributes */ > +#ifdef CONFIG_ARM64_BRBE > + u64 reg_brbidr; > +#endif > }; > > #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu)) > -- > 2.25.1 >
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