linux-kernel - Re: [RFC-PATCH] x86: really use __builtin_memcmp on x86

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: <87prl4otzx.fsf@basil.nowhere.org>
Date:	Mon, 10 Nov 2008 09:38:58 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	Harvey Harrison <harvey.harrison@...il.com>
Cc:	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC-PATCH] x86: really use __builtin_memcmp on x86_32

Harvey Harrison <harvey.harrison@...il.com> writes:

> Impact: prevent generic code from overriding __builtin_memcmp
>
> lib/string.c was using a generic implementation of memcmp
> because __HAVE_ARCH_MEMCMP was not defined and it was then doing
> #undef memcmp and defining a generic version.

gcc sometimes decides to not inline memcmp, so an out of line
version is always needed even when __builtin_memcmp is used.

While in theory x86 could supply an optimized version,
memcmp is relatively rarely used (and in many cases inlined),
so adding an assembler version for x86 is likely not worth
it.

-Andi

-- 
ak@...ux.intel.com
--
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/