From: Herbert Xu <herbert@gondor.apana.org.au>
Subject: Re: x86-64: Maintain 16-byte stack alignment
Date: Wed, 11 Jan 2017 11:15:26 +0800
Message-ID: <20170111031526.GB4515@gondor.apana.org.au>
References: <20170110143340.GA3787@gondor.apana.org.au>
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Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andy Lutomirski <luto@kernel.org>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
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On Tue, Jan 10, 2017 at 05:30:48PM +0000, Ard Biesheuvel wrote:
> 
> Apologies for introducing this breakage. It seemed like an obvious and
> simple cleanup, so I didn't even bother to mention it in the commit
> log, but if the kernel does not guarantee 16 byte alignment, I guess
> we should revert to the old method. If SSE instructions are the only
> ones that require this alignment, then I suppose not having a ABI
> conforming stack pointer should not be an issue in general.

I think we need to address this regardless of your patch.  You
won't be the last person to use __attribute__ to get 16-byte
alignment on the stack.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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