From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757829Ab3HPWrl (ORCPT ); Fri, 16 Aug 2013 18:47:41 -0400 Received: from mga02.intel.com ([134.134.136.20]:39262 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757805Ab3HPWrj (ORCPT ); Fri, 16 Aug 2013 18:47:39 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.89,897,1367996400"; d="scan'208";a="363878652" From: Andi Kleen To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, peterz@infradead.org, akpm@linux-foundation.org, Andi Kleen Subject: [PATCH 1/6] x86: Add 1/2/4/8 byte optimization to 64bit __copy_{from,to}_user_inatomic Date: Fri, 16 Aug 2013 14:17:19 -0700 Message-Id: <1376687844-19857-2-git-send-email-andi@firstfloor.org> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1376687844-19857-1-git-send-email-andi@firstfloor.org> References: <1376687844-19857-1-git-send-email-andi@firstfloor.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andi Kleen The 64bit __copy_{from,to}_user_inatomic always called copy_from_user_generic, but skipped the special optimizations for 1/2/4/8 byte accesses. This especially hurts the futex call, which accesses the 4 byte futex user value with a complicated fast string operation in a function call, instead of a single movl. Use __copy_{from,to}_user for _inatomic instead to get the same optimizations. The only problem was the might_fault() in those functions. So move that to new wrapper and call __copy_{f,t}_user_nocheck() from *_inatomic directly. 32bit already did this correctly by duplicating the code. Signed-off-by: Andi Kleen --- arch/x86/include/asm/uaccess_64.h | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h index 4f7923d..64476bb 100644 --- a/arch/x86/include/asm/uaccess_64.h +++ b/arch/x86/include/asm/uaccess_64.h @@ -77,11 +77,10 @@ int copy_to_user(void __user *dst, const void *src, unsigned size) } static __always_inline __must_check -int __copy_from_user(void *dst, const void __user *src, unsigned size) +int __copy_from_user_nocheck(void *dst, const void __user *src, unsigned size) { int ret = 0; - might_fault(); if (!__builtin_constant_p(size)) return copy_user_generic(dst, (__force void *)src, size); switch (size) { @@ -121,11 +120,17 @@ int __copy_from_user(void *dst, const void __user *src, unsigned size) } static __always_inline __must_check -int __copy_to_user(void __user *dst, const void *src, unsigned size) +int __copy_from_user(void *dst, const void __user *src, unsigned size) +{ + might_fault(); + return __copy_from_user_nocheck(dst, src, size); +} + +static __always_inline __must_check +int __copy_to_user_nocheck(void __user *dst, const void *src, unsigned size) { int ret = 0; - might_fault(); if (!__builtin_constant_p(size)) return copy_user_generic((__force void *)dst, src, size); switch (size) { @@ -165,6 +170,13 @@ int __copy_to_user(void __user *dst, const void *src, unsigned size) } static __always_inline __must_check +int __copy_to_user(void __user *dst, const void *src, unsigned size) +{ + might_fault(); + return __copy_to_user_nocheck(dst, src, size); +} + +static __always_inline __must_check int __copy_in_user(void __user *dst, const void __user *src, unsigned size) { int ret = 0; @@ -220,13 +232,13 @@ int __copy_in_user(void __user *dst, const void __user *src, unsigned size) static __must_check __always_inline int __copy_from_user_inatomic(void *dst, const void __user *src, unsigned size) { - return copy_user_generic(dst, (__force const void *)src, size); + return __copy_from_user_nocheck(dst, (__force const void *)src, size); } static __must_check __always_inline int __copy_to_user_inatomic(void __user *dst, const void *src, unsigned size) { - return copy_user_generic((__force void *)dst, src, size); + return __copy_to_user_nocheck((__force void *)dst, src, size); } extern long __copy_user_nocache(void *dst, const void __user *src, -- 1.8.3.1