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

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Date:   Thu, 24 Jun 2021 07:09:45 -0000
From:   "tip-bot2 for Kan Liang" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Yasin, Ahmad" <ahmad.yasin@...el.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        stable@...r.kernel.org, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: perf/core] perf/x86/intel: Fix instructions:ppp support in
 Sapphire Rapids

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     1d5c7880992a06679585e7e568cc679c0c5fd4f2
Gitweb:        https://git.kernel.org/tip/1d5c7880992a06679585e7e568cc679c0c5fd4f2
Author:        Kan Liang <kan.liang@...ux.intel.com>
AuthorDate:    Fri, 18 Jun 2021 08:12:54 -07:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Wed, 23 Jun 2021 18:30:55 +02:00

perf/x86/intel: Fix instructions:ppp support in Sapphire Rapids

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>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/r/1624029174-122219-4-git-send-email-kan.liang@linux.intel.com
---
 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;