linux-kernel - Re: [PATCH 1/1] perf cs-etm: Output 0 instead of 0xdeadbeef when exception packets are flushed

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Message-ID: <ZqO0I1zLFX_oLYaY@x1>
Date: Fri, 26 Jul 2024 11:35:15 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Mike Leach <mike.leach@...aro.org>
Cc: James Clark <james.clark@...aro.org>, coresight@...ts.linaro.org,
	gankulkarni@...amperecomputing.com, leo.yan@....com,
	suzuki.poulose@....com, John Garry <john.g.garry@...cle.com>,
	Will Deacon <will@...nel.org>, James Clark <james.clark@....com>,
	Leo Yan <leo.yan@...ux.dev>, Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	"Liang, Kan" <kan.liang@...ux.intel.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] perf cs-etm: Output 0 instead of 0xdeadbeef when
 exception packets are flushed

On Tue, Jul 23, 2024 at 04:09:29PM +0100, Mike Leach wrote:
> On Mon, 22 Jul 2024 at 16:28, James Clark <james.clark@...aro.org> wrote:
> >
> > Normally exception packets don't directly output a branch sample, but
> > if they're the last record in a buffer then they will. Because they
> > don't have addresses set we'll see the placeholder value
> > CS_ETM_INVAL_ADDR (0xdeadbeef) in the output.
> >
> > Since commit 6035b6804bdf ("perf cs-etm: Support dummy address value for
> > CS_ETM_TRACE_ON packet") we've used 0 as an externally visible "not set"
> > address value. For consistency reasons and to not make exceptions look
> > like an error, change them to use 0 too.

<SNIP>
 
> Reviewed-by: Mike Leach <mike.leach@...aro.org>

Thanks, applied to tmp.perf-tools-next,

- Arnaldo