linux-kernel - Re: [PATCH] i386/audit: stop scribbling on the stack frame

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Message-ID: <alpine.DEB.2.11.1410272212420.5308@nanos>
Date:	Mon, 27 Oct 2014 22:18:21 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Eric Paris <eparis@...hat.com>
cc:	Richard Guy Briggs <rgb@...hat.com>, linux-kernel@...r.kernel.org,
	przanoni@...il.com, mingo@...nel.org, hpa@...ux.intel.com,
	hpa@...or.com, linux-tip-commits@...r.kernel.org,
	linux-audit@...hat.com
Subject: Re: [PATCH] i386/audit: stop scribbling on the stack frame

On Mon, 27 Oct 2014, Eric Paris wrote:

> My patch was already committed to the -tip urgent branch.  I believe any
> optimization should be based on that branch, Richard.  If you are trying
> to wrangle every bit of speed out of this, should you
> 
> push %esi;
> push %edi;
> CFI_ADJUST_CFA_OFFSET 8

Wrong. You want to use pushl_cfi as you need the CFI adjustment after
each modification of esp.

> call __audit_syscall_entry
> pop;
> pop;
> CFI_ADJUST_CFA_OFFSET -8
> 
> Instead of using the pushl_cfi and popl_cfi macros?

Wrong again. See above. Aside of that, why do you want to use pop at
all? All we care about is adjusting esp, right?

Thanks,

	tglx
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