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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Wed, 27 Jul 2022 09:25:18 +0200
Message-ID: <CACRpkdbu8M84s2rPsKTwMmMXeeYEmNVaXFnp1hsKM0Dc9jzNfw@mail.gmail.com>
Subject: Re: [PATCH v3 4/4] ARM: stacktrace: Convert stacktrace to generic ARCH_STACKWALK
To:     Li Huafei <lihuafei1@huawei.com>
Cc:     linux@armlinux.org.uk, rmk+kernel@armlinux.org.uk, ardb@kernel.org,
        will@kernel.org, broonie@kernel.org, mark.rutland@arm.com,
        peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
        alexander.shishkin@linux.intel.com, jolsa@kernel.org,
        namhyung@kernel.org, arnd@arndb.de, rostedt@goodmis.org,
        nick.hawkins@hpe.com, john@phrozen.org, mhiramat@kernel.org,
        ast@kernel.org, linyujun809@huawei.com, ndesaulniers@google.com,
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        linux-perf-users@vger.kernel.org
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On Wed, Jul 27, 2022 at 6:03 AM Li Huafei <lihuafei1@huawei.com> wrote:

> Historically architectures have had duplicated code in their stack trace
> implementations for filtering what gets traced. In order to avoid this
> duplication some generic code has been provided using a new interface
> arch_stack_walk(), enabled by selecting ARCH_STACKWALK in Kconfig, which
> factors all this out into the generic stack trace code. Convert ARM to
> use this common infrastructure.
>
> When initializing the stack frame of the current task, arm64 uses
> __builtin_frame_address(1) to initialize the frame pointer, skipping
> arch_stack_walk(), see the commit c607ab4f916d ("arm64: stacktrace:
> don't trace arch_ stack_walk()"). Since __builtin_frame_address(1) does
> not work on ARM, unwind_frame() is used to unwind the stack one layer
> forward before calling walk_stackframe().
>
> Signed-off-by: Li Huafei <lihuafei1@huawei.com>

Looks good to me.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij