From: Herbert Xu <herbert@gondor.apana.org.au>
Subject: Re: x86-64: Maintain 16-byte stack alignment
Date: Fri, 13 Jan 2017 16:36:48 +0800
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Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andy Lutomirski <luto@kernel.org>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Andy Lutomirski <luto@amacapital.net>
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On Thu, Jan 12, 2017 at 12:08:07PM -0800, Andy Lutomirski wrote:
>
> I think we have some inline functions that do asm volatile ("call
> ..."), and I don't see any credible way of forcing alignment short of
> generating an entirely new stack frame and aligning that.  Ick.  This

A straight asm call from C should always work because gcc keeps
the stack aligned in the prologue.

The only problem with inline assembly is when you start pushing
things onto the stack directly.

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