linux-kernel - Re: [PATCH v3] perf: tests: Disable breakpoint tests on ARM (32-bit)

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Message-ID: <20181204140615.GB5837@arm.com>
Date:   Tue, 4 Dec 2018 14:06:16 +0000
From:   Will Deacon <will.deacon@....com>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>
Subject: Re: [PATCH v3] perf: tests: Disable breakpoint tests on ARM (32-bit)

On Mon, Dec 03, 2018 at 11:11:36AM -0800, Florian Fainelli wrote:
> breakpoint tests on the ARM 32-bit kernel are broken in several ways.
> 
> The breakpoint length requested does not necessarily match whether the
> function address has the Thumb bit (bit 0) set or not, and this does
> matter to the ARM kernel hw_breakpoint infrastructure. See [1] for
> background.
> 
> [1]: https://lkml.org/lkml/2018/11/15/205
> 
> As Will indicated, the overflow handling would require single-stepping
> which is not supported at the moment. Just disable those tests for the
> ARM 32-bit platforms and update the comment above to explain these
> limitations.
> 
> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
> ---
> Changes in v3:
> 
> - directly incorporate Will's comment, Will can you add your
>   Signed-off-by?

Of course:

Co-developed-by: Will Deacon <will.deacon@....com>
Signed-off-by: Will Deacon <will.deacon@....com>

Will