[RFC 1/3] x86: perf: Move RDPMC event flag to a common definition

[Rob Herring <robh@kernel.org>]

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.

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 1eb45139fcc6..03f87fd4c017 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2471,7 +2471,7 @@ 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 2bf1c7ea2758..84d803c5cc87 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 2d510ad750ed..f5815448ca9b 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
 			int		flags;
 
 			struct hw_perf_event_extra extra_reg;
-- 
2.27.0