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Date: Mon, 21 Aug 2017 09:53:09 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Matthias Kaehlcke <mka@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
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        Stephen Hines <srhines@google.com>, Kees Cook <keescook@chromium.org>,
        Arnd Bergmann <arnd@arndb.de>, Bernhard.Rosenkranzer@linaro.org
Subject: Re: [PATCH] x86/build: Use cc-option to validate stack alignment
 parameter
Message-ID: <20170821075309.pqppfsxmyy2oqoow@gmail.com>
References: <20170817182047.176752-1-mka@chromium.org>
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* Matthias Kaehlcke <mka@chromium.org> wrote:

> With 8f91869766c0 ("x86/build: Fix stack alignment for CLang") cc-option
> is only used to determine the name of the stack alignment option supported
> by the compiler, but not to verify that the actual parameter <option>=N is
> valid in combination with the other CFLAGS. This causes problems with older
> gcc versions which only support stack alignment on a boundary of 16 bytes
> or higher.
> 
> Also use (__)cc_option to add the stack alignment option to CFLAGS to
> make sure only valid options are added.
> 
> Fixes: 8f91869766c0 ("x86/build: Fix stack alignment for CLang")
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>

I've added the kbuild-bot Reported-by tag to document (and credit) how this bug 
was found.

Thanks,

	Ingo