This is a note to let you know that I've just added the patch titled
arm64: perf: Fix 64-bit event counter read truncation
to the 5.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm64-perf-fix-64-bit-event-counter-read-truncation.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7bb8bc6eb550116c504fb25af8678b9d7ca2abc5 Mon Sep 17 00:00:00 2001
From: Rob Herring <robh@xxxxxxxxxx>
Date: Tue, 9 Mar 2021 17:44:12 -0700
Subject: arm64: perf: Fix 64-bit event counter read truncation
From: Rob Herring <robh@xxxxxxxxxx>
commit 7bb8bc6eb550116c504fb25af8678b9d7ca2abc5 upstream.
Commit 0fdf1bb75953 ("arm64: perf: Avoid PMXEV* indirection") changed
armv8pmu_read_evcntr() to return a u32 instead of u64. The result is
silent truncation of the event counter when using 64-bit counters. Given
the offending commit appears to have passed thru several folks, it seems
likely this was a bad rebase after v8.5 PMU 64-bit counters landed.
Cc: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Cc: Julien Thierry <julien.thierry.kdev@xxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 0fdf1bb75953 ("arm64: perf: Avoid PMXEV* indirection")
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Reviewed-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Link: https://lore.kernel.org/r/20210310004412.1450128-1-robh@xxxxxxxxxx
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/perf_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -460,7 +460,7 @@ static inline int armv8pmu_counter_has_o
return pmnc & BIT(ARMV8_IDX_TO_COUNTER(idx));
}
-static inline u32 armv8pmu_read_evcntr(int idx)
+static inline u64 armv8pmu_read_evcntr(int idx)
{
u32 counter = ARMV8_IDX_TO_COUNTER(idx);
Patches currently in stable-queue which might be from robh@xxxxxxxxxx are
queue-5.11/arm64-perf-fix-64-bit-event-counter-read-truncation.patch
