Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753044Ab0KBApq (ORCPT ); Mon, 1 Nov 2010 20:45:46 -0400 Received: from hera.kernel.org ([140.211.167.34]:46190 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750966Ab0KBApm (ORCPT ); Mon, 1 Nov 2010 20:45:42 -0400 Date: Tue, 2 Nov 2010 00:45:06 GMT From: "tip-bot for Ma, Ling" Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, ling.ma@intel.com, tglx@linutronix.de, hpa@linux.intel.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, ling.ma@intel.com, tglx@linutronix.de, hpa@linux.intel.com In-Reply-To: References: To: linux-tip-commits@vger.kernel.org Subject: [tip:core/locking] x86, mem: Don't implement forward memmove() as memcpy() Message-ID: Git-Commit-ID: fdf4289679fd41d76553ce224750e9737cd80eea X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Tue, 02 Nov 2010 00:45:29 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3663 Lines: 137 Commit-ID: fdf4289679fd41d76553ce224750e9737cd80eea Gitweb: http://git.kernel.org/tip/fdf4289679fd41d76553ce224750e9737cd80eea Author: Ma, Ling AuthorDate: Mon, 23 Aug 2010 14:11:12 -0700 Committer: H. Peter Anvin CommitDate: Mon, 23 Aug 2010 14:14:27 -0700 x86, mem: Don't implement forward memmove() as memcpy() memmove() allow source and destination address to be overlap, but there is no such limitation for memcpy(). Therefore, explicitly implement memmove() in both the forwards and backward directions, to give us the ability to optimize memcpy(). Signed-off-by: Ma Ling LKML-Reference: Signed-off-by: H. Peter Anvin --- arch/x86/lib/memcpy_32.c | 38 ++++++++++++++++++++++++++---------- arch/x86/lib/memmove_64.c | 46 ++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 68 insertions(+), 16 deletions(-) diff --git a/arch/x86/lib/memcpy_32.c b/arch/x86/lib/memcpy_32.c index 5415a9d..be424df 100644 --- a/arch/x86/lib/memcpy_32.c +++ b/arch/x86/lib/memcpy_32.c @@ -25,19 +25,35 @@ void *memmove(void *dest, const void *src, size_t n) int d0, d1, d2; if (dest < src) { - memcpy(dest, src, n); + if ((dest + n) < src) + return memcpy(dest, src, n); + else + __asm__ __volatile__( + "rep\n\t" + "movsb\n\t" + : "=&c" (d0), "=&S" (d1), "=&D" (d2) + :"0" (n), + "1" (src), + "2" (dest) + :"memory"); + } else { - __asm__ __volatile__( - "std\n\t" - "rep\n\t" - "movsb\n\t" - "cld" - : "=&c" (d0), "=&S" (d1), "=&D" (d2) - :"0" (n), - "1" (n-1+src), - "2" (n-1+dest) - :"memory"); + + if((src + count) < dest) + return memcpy(dest, src, count); + else + __asm__ __volatile__( + "std\n\t" + "rep\n\t" + "movsb\n\t" + "cld" + : "=&c" (d0), "=&S" (d1), "=&D" (d2) + :"0" (n), + "1" (n-1+src), + "2" (n-1+dest) + :"memory"); } + return dest; } EXPORT_SYMBOL(memmove); diff --git a/arch/x86/lib/memmove_64.c b/arch/x86/lib/memmove_64.c index 0a33909..ecacc4b 100644 --- a/arch/x86/lib/memmove_64.c +++ b/arch/x86/lib/memmove_64.c @@ -8,13 +8,49 @@ #undef memmove void *memmove(void *dest, const void *src, size_t count) { + unsigned long d0, d1, d2, d3; if (dest < src) { - return memcpy(dest, src, count); + if ((dest + count) < src) + return memcpy(dest, src, count); + else + __asm__ __volatile__( + "movq %0, %3\n\t" + "shr $3, %0\n\t" + "andq $7, %3\n\t" + "rep\n\t" + "movsq\n\t" + "movq %3, %0\n\t" + "rep\n\t" + "movsb" + : "=&c" (d0), "=&S" (d1), "=&D" (d2), "=r" (d3) + :"0" (count), + "1" (src), + "2" (dest) + :"memory"); } else { - char *p = dest + count; - const char *s = src + count; - while (count--) - *--p = *--s; + if((src + count) < dest) + return memcpy(dest, src, count); + else + __asm__ __volatile__( + "movq %0, %3\n\t" + "lea -8(%1, %0), %1\n\t" + "lea -8(%2, %0), %2\n\t" + "shr $3, %0\n\t" + "andq $7, %3\n\t" + "std\n\t" + "rep\n\t" + "movsq\n\t" + "lea 7(%1), %1\n\t" + "lea 7(%2), %2\n\t" + "movq %3, %0\n\t" + "rep\n\t" + "movsb\n\t" + "cld" + : "=&c" (d0), "=&S" (d1), "=&D" (d2), "=r" (d3) + :"0" (count), + "1" (src), + "2" (dest) + :"memory"); } return dest; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/