From: James Clark <james.clark@linaro.org>
To: Leo Yan <leo.yan@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
coresight@lists.linaro.org, Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Mathieu Poirier <mathieu.poirier@linaro.org>
Subject: Re: [PATCH 0/2] perf: Order SPE and TRBE padding before publishing AUX head
Date: Fri, 16 Oct 2026 11:18:44 +0100 [thread overview]
Message-ID: <53999f08-bbfb-462e-8521-383aba65f2a9@linaro.org> (raw)
In-Reply-To: <20261015-add_barriers_for_perf_aux_output_skip-v1-0-5847d0578859@arm.com>
On 15/10/2026 16:51, Leo Yan wrote:
> SPE and TRBE write padding into their AUX buffers before advancing
> aux_head. Add the missing write barriers so that a userspace reader on
> another CPU cannot observe the new head before the padding stores
> become visible.
>
> AUX producers must make their data visible before publishing aux_head.
> The required synchronization depends on the trace hardware and CPU
> memory model, so the barriers belong in the drivers rather than in
> perf_aux_output_skip() or perf_aux_output_end(). The TRBE change also
> covers padding inserted by the overwrite erratum workaround before
> perf_aux_output_end().
>
> Signed-off-by: Leo Yan <leo.yan@arm.com>
> ---
> Leo Yan (2):
> perf: arm_spe: Order padding before publishing AUX head
> coresight: trbe: Order padding before publishing AUX head
>
> drivers/hwtracing/coresight/coresight-trbe.c | 2 ++
> drivers/perf/arm_spe_pmu.c | 5 ++++-
> 2 files changed, 6 insertions(+), 1 deletion(-)
> ---
> base-commit: 0fcb05b72344f40806cbe810de8872f1698bf053
> change-id: 20261015-add_barriers_for_perf_aux_output_skip-70356815b2bd
>
> Best regards,
Reviewed-by: James Clark <james.clark@linaro.org>
prev parent reply other threads:[~2026-10-16 10:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-15 15:51 Leo Yan
2026-10-15 15:51 ` [PATCH 1/2] perf: arm_spe: Order " Leo Yan
2026-10-15 15:51 ` [PATCH 2/2] coresight: trbe: " Leo Yan
2026-10-16 10:18 ` James Clark [this message]
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