linux-kernel - Re: BUG: GCC-4.4.x changes the function frame on some functions

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4B056FAD.2080500@redhat.com>
Date:	Thu, 19 Nov 2009 16:17:49 +0000
From:	Andrew Haley <aph@...hat.com>
To:	Thomas Gleixner <tglx@...utronix.de>
CC:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	feng.tang@...el.com, Fr??d??ric Weisbecker <fweisbec@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Peter Zijlstra <peterz@...radead.org>, jakub@...hat.com,
	gcc@....gnu.org
Subject: Re: BUG: GCC-4.4.x changes the function frame on some functions

Thomas Gleixner wrote:
> On Thu, 19 Nov 2009, Andrew Haley wrote:
>> Thomas Gleixner wrote:
>>> There is no real obvious reason why the edi magic needs to be done
>>> _before_ 
>>>
>>> 	push   %ebp
>>> 	mov    %esp,%ebp
>> Sure there is: unless you do the adjustment first %ebp won't be 16-aligned.
> 
> And why is this not done in 99% of the functions in the kernel, just
> in this one and some random others ?

If I could see the function I might be able to tell you.  It's either a
performance enhancement, something to do with SSE, or it's a bug.

Andrew.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/