[PATCH v13 1/5] x86: perf: Move RDPMC event flag to a common definition

From: Rob Herring <robh@kernel.org>
Date: 2021-12-08 20:11:31
Also in: linux-perf-users, lkml
Subsystem: performance events subsystem, the rest, x86 architecture (32-bit and 64-bit) · Maintainers: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds, Thomas Gleixner, Borislav Petkov, Dave Hansen

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: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <redacted>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Kan Liang <redacted>
Cc: Thomas Gleixner <redacted>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-perf-users@vger.kernel.org
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Thomas Gleixner <redacted>
Signed-off-by: Rob Herring <robh@kernel.org>
---
v11:
 - Move PERF_EVENT_FLAG_USER_READ_CNT definition above struct
---
 arch/x86/events/core.c       | 10 +++++-----
 arch/x86/events/perf_event.h |  2 +-
 include/linux/perf_event.h   |  9 +++++++++
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 38b2c779146f..68dea7ce6a22 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c

@@ -2476,7 +2476,7 @@ 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;
 }

@@ -2510,7 +2510,7 @@ 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;
 
 	/*

@@ -2531,7 +2531,7 @@ 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))

@@ -2542,7 +2542,7 @@ 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))

@@ -2725,7 +2725,7 @@ 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 5480db242083..9d376e528dfc 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h

@@ -74,7 +74,7 @@ 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 0dcfd265beed..ba9467972c09 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h

@@ -129,6 +129,15 @@ struct hw_perf_event_extra {
 	int		idx;	/* index in shared_regs->regs[] */
 };
 
+/**
+ * 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
+
 /**
  * struct hw_perf_event - performance event hardware details:
  */

-- 
2.32.0


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