Messages in this thread | | | Date | Wed, 13 Oct 2021 18:25:38 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH v10 1/5] x86: perf: Move RDPMC event flag to a common definition |
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Hi Rob,
On Tue, Sep 14, 2021 at 03:47:56PM -0500, Rob Herring wrote: > In preparation to enable user counter access on arm64 and to move some > of the user access handling to perf core, create a common event flag for > user counter access and convert x86 to use it. > > Since the architecture specific flags start at the LSB, starting at the > MSB for common flags.
Minor comments below (definition rename, and a comment block), but with those:
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Peter, are you happy with this from the x86 side?
> Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Arnaldo Carvalho de Melo <acme@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> > Cc: Jiri Olsa <jolsa@redhat.com> > Cc: Namhyung Kim <namhyung@kernel.org> > Cc: Kan Liang <kan.liang@linux.intel.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Borislav Petkov <bp@alien8.de> > Cc: x86@kernel.org > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: linux-perf-users@vger.kernel.org > Signed-off-by: Rob Herring <robh@kernel.org> > --- > arch/x86/events/core.c | 10 +++++----- > arch/x86/events/perf_event.h | 2 +- > include/linux/perf_event.h | 2 ++ > 3 files changed, 8 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c > index 2a57dbed4894..2bd50fc061e1 100644 > --- a/arch/x86/events/core.c > +++ b/arch/x86/events/core.c > @@ -2469,7 +2469,7 @@ static int x86_pmu_event_init(struct perf_event *event) > > if (READ_ONCE(x86_pmu.attr_rdpmc) && > !(event->hw.flags & PERF_X86_EVENT_LARGE_PEBS)) > - event->hw.flags |= PERF_X86_EVENT_RDPMC_ALLOWED; > + event->hw.flags |= PERF_EVENT_FLAG_USER_READ_CNT; > > return err; > } > @@ -2503,7 +2503,7 @@ void perf_clear_dirty_counters(void) > > static void x86_pmu_event_mapped(struct perf_event *event, struct mm_struct *mm) > { > - if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED)) > + if (!(event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)) > return; > > /* > @@ -2524,7 +2524,7 @@ static void x86_pmu_event_mapped(struct perf_event *event, struct mm_struct *mm) > > static void x86_pmu_event_unmapped(struct perf_event *event, struct mm_struct *mm) > { > - if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED)) > + if (!(event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)) > return; > > if (atomic_dec_and_test(&mm->context.perf_rdpmc_allowed)) > @@ -2535,7 +2535,7 @@ static int x86_pmu_event_idx(struct perf_event *event) > { > struct hw_perf_event *hwc = &event->hw; > > - if (!(hwc->flags & PERF_X86_EVENT_RDPMC_ALLOWED)) > + if (!(hwc->flags & PERF_EVENT_FLAG_USER_READ_CNT)) > return 0; > > if (is_metric_idx(hwc->idx)) > @@ -2718,7 +2718,7 @@ void arch_perf_update_userpage(struct perf_event *event, > userpg->cap_user_time = 0; > userpg->cap_user_time_zero = 0; > userpg->cap_user_rdpmc = > - !!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED); > + !!(event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT); > userpg->pmc_width = x86_pmu.cntval_bits; > > if (!using_native_sched_clock() || !sched_clock_stable()) > diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h > index e3ac05c97b5e..49f68b15745f 100644 > --- a/arch/x86/events/perf_event.h > +++ b/arch/x86/events/perf_event.h > @@ -73,7 +73,7 @@ static inline bool constraint_match(struct event_constraint *c, u64 ecode) > #define PERF_X86_EVENT_PEBS_NA_HSW 0x0010 /* haswell style datala, unknown */ > #define PERF_X86_EVENT_EXCL 0x0020 /* HT exclusivity on counter */ > #define PERF_X86_EVENT_DYNAMIC 0x0040 /* dynamic alloc'd constraint */ > -#define PERF_X86_EVENT_RDPMC_ALLOWED 0x0080 /* grant rdpmc permission */ > + > #define PERF_X86_EVENT_EXCL_ACCT 0x0100 /* accounted EXCL event */ > #define PERF_X86_EVENT_AUTO_RELOAD 0x0200 /* use PEBS auto-reload */ > #define PERF_X86_EVENT_LARGE_PEBS 0x0400 /* use large PEBS */ > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index fe156a8170aa..12debf008d39 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -142,6 +142,8 @@ struct hw_perf_event { > int event_base_rdpmc; > int idx; > int last_cpu; > + > +#define PERF_EVENT_FLAG_USER_READ_CNT 0x80000000
I realise this matches the style of PERF_HES_* and PERF_EF_*. but could we please arrange this like the PERF_PMU_CAP_* definitions, and move this immediately before the struct hw_perf_event defintion, with a comment block, e.g.
/* * hw_perf_event::flag values * * PERF_EVENT_FLAG_ARCH bits are reserved for architecture-specific * usage. */ #define PERF_EVENT_FLAG_ARCH 0x0000ffff #define PERF_EVENT_FLAG_USER_READ_CNT 0x80000000
Thanks, Mark.
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