linux-kernel - [PATCH 3/3] perf/x86/intel: Fix instructions:ppp support in Sapphire Rapids

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Date:   Fri, 18 Jun 2021 08:12:54 -0700
From:   kan.liang@...ux.intel.com
To:     peterz@...radead.org, mingo@...hat.com,
        linux-kernel@...r.kernel.org
Cc:     acme@...nel.org, jolsa@...hat.com, namhyung@...nel.org,
        ak@...ux.intel.com, Kan Liang <kan.liang@...ux.intel.com>,
        stable@...r.kernel.org
Subject: [PATCH 3/3] perf/x86/intel: Fix instructions:ppp support in Sapphire Rapids

From: Kan Liang <kan.liang@...ux.intel.com>

Perf errors out when sampling instructions:ppp.

$ perf record -e instructions:ppp -- true
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument)
for event (instructions:ppp).

The instruction PDIR is only available on the fixed counter 0. The event
constraint has been updated to fixed0_constraint in
icl_get_event_constraints(). The Sapphire Rapids codes unconditionally
error out for the event which is not available on the GP counter 0.

Make the instructions:ppp an exception.

Fixes: 61b985e3e775 ("perf/x86/intel: Add perf core PMU support for Sapphire Rapids")
Reported-by: Yasin, Ahmad <ahmad.yasin@...el.com>
Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
Cc: stable@...r.kernel.org
---
 arch/x86/events/intel/core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index e442b55..e355db5 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -4032,8 +4032,10 @@ spr_get_event_constraints(struct cpu_hw_events *cpuc, int idx,
 	 * The :ppp indicates the Precise Distribution (PDist) facility, which
 	 * is only supported on the GP counter 0. If a :ppp event which is not
 	 * available on the GP counter 0, error out.
+	 * Exception: Instruction PDIR is only available on the fixed counter 0.
 	 */
-	if (event->attr.precise_ip == 3) {
+	if ((event->attr.precise_ip == 3) &&
+	    !constraint_match(&fixed0_constraint, event->hw.config)) {
 		if (c->idxmsk64 & BIT_ULL(0))
 			return &counter0_constraint;
 
-- 
2.7.4