Re: x86-64: Maintain 16-byte stack alignment

From	Herbert Xu <herbert@gondor.apana.org.au>
Newsgroups	linux.kernel
Subject	Re: x86-64: Maintain 16-byte stack alignment
Date	2017-01-11 04:20 +0100
Message-ID	<sYhC9-1wa-7@gated-at.bofh.it> (permalink)
References	<sY5KF-2vR-21@gated-at.bofh.it> <sY8yR-4e0-15@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Thread

x86-64: Maintain 16-byte stack alignment Herbert Xu <herbert@gondor.apana.org.au> - 2017-01-10 15:40 +0100
  Re: x86-64: Maintain 16-byte stack alignment Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-01-10 18:40 +0100
    Re: x86-64: Maintain 16-byte stack alignment Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-01-10 20:20 +0100
      Re: x86-64: Maintain 16-byte stack alignment Andy Lutomirski <luto@amacapital.net> - 2017-01-10 20:30 +0100
        Re: x86-64: Maintain 16-byte stack alignment Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-01-10 21:10 +0100
          Re: x86-64: Maintain 16-byte stack alignment Andy Lutomirski <luto@amacapital.net> - 2017-01-11 00:30 +0100
            Re: x86-64: Maintain 16-byte stack alignment Herbert Xu <herbert@gondor.apana.org.au> - 2017-01-11 04:30 +0100
        Re: x86-64: Maintain 16-byte stack alignment Herbert Xu <herbert@gondor.apana.org.au> - 2017-01-11 04:30 +0100
    Re: x86-64: Maintain 16-byte stack alignment Andy Lutomirski <luto@amacapital.net> - 2017-01-10 20:50 +0100
      Re: x86-64: Maintain 16-byte stack alignment Herbert Xu <herbert@gondor.apana.org.au> - 2017-01-11 04:20 +0100
    Re: x86-64: Maintain 16-byte stack alignment Herbert Xu <herbert@gondor.apana.org.au> - 2017-01-11 04:20 +0100
    Re: x86-64: Maintain 16-byte stack alignment Herbert Xu <herbert@gondor.apana.org.au> - 2017-01-12 07:20 +0100
      Re: x86-64: Maintain 16-byte stack alignment Herbert Xu <herbert@gondor.apana.org.au> - 2017-01-12 09:10 +0100
      Re: x86-64: Maintain 16-byte stack alignment Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-01-12 09:10 +0100

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