linux-kernel - Re: [GIT PULL] x86/alternatives padding

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Message-ID: <20150304114151.GD3516@pd.tnic>
Date:	Wed, 4 Mar 2015 12:41:52 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	x86-ml <x86@...nel.org>, Peter Zijlstra <peterz@...radead.org>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Andy Lutomirski <luto@...capital.net>,
	lkml <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [GIT PULL] x86/alternatives padding

On Wed, Mar 04, 2015 at 12:22:06PM +0100, Borislav Petkov wrote:
> Well, kernel image doesn't change while vmlinux shows only a very small
> .text increase of about 2K. I'm not sure yet why that happens though
> because it shouldn't be the padding. Because we will have to do it
> anyway, this patchset makes it automatic instead of by-hand, so to
> speak.
> 
> Let me bisect it and see which patch adds the increase.

Doh, of course. I've added u8 padlen to the alternative instruction
entry struct. For 2Kish alt sites in total, this explains the almost
exact same increase in text size:

   text    data     bss     dec     hex filename
12290539        1595264 1085440 14971243         e4716b vmlinux

338ea55579d1... x86/lib/copy_user_64.S: Remove FIX_ALIGNMENT define
   text    data     bss     dec     hex filename
12290539        1595264 1085440 14971243         e4716b vmlinux

db477a3386de... x86/alternatives: Cleanup DPRINTK macro
   text    data     bss     dec     hex filename
12290539        1595264 1085440 14971243         e4716b vmlinux

4332195c5615... x86/alternatives: Add instruction padding
   text    data     bss     dec     hex filename
12293030        1595264 1085440 14973734         e47b26 vmlinux
^^^^^^^

Ok, that's sorted out now.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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