From patchwork Thu May 24 20:26:13 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Miller X-Patchwork-Id: 161198 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id E2EF1B6EEC for ; Fri, 25 May 2012 06:26:15 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755382Ab2EXU0P (ORCPT ); Thu, 24 May 2012 16:26:15 -0400 Received: from shards.monkeyblade.net ([198.137.202.13]:42681 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755036Ab2EXU0O (ORCPT ); Thu, 24 May 2012 16:26:14 -0400 Received: from localhost (cpe-66-108-119-99.nyc.res.rr.com [66.108.119.99]) (authenticated bits=0) by shards.monkeyblade.net (8.14.4/8.14.4) with ESMTP id q4OKQDcX001230 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NO); Thu, 24 May 2012 13:26:14 -0700 Date: Thu, 24 May 2012 16:26:13 -0400 (EDT) Message-Id: <20120524.162613.256050233513717246.davem@davemloft.net> To: linux-arch@vger.kernel.org CC: sparclinux@vger.kernel.org Subject: [PATCH 1/3 v2] sparc: Increase portability of strncpy_from_user() implementation. From: David Miller X-Mailer: Mew version 6.5 on Emacs 24.0.95 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.6 (shards.monkeyblade.net [198.137.202.13]); Thu, 24 May 2012 13:26:14 -0700 (PDT) Sender: sparclinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: sparclinux@vger.kernel.org Hide details of maximum user address calculation in a new asm/uaccess.h interface named user_addr_max(). Provide little-endian implementation in find_zero(), which should work but can probably be improved. Abstrace alignment check behind IS_UNALIGNED() macro. Kill double-semicolon, noticed by David Howells. Signed-off-by: David S. Miller --- arch/sparc/include/asm/uaccess.h | 3 +++ arch/sparc/lib/usercopy.c | 32 +++++++++++++++++++++++++++----- 2 files changed, 30 insertions(+), 5 deletions(-) diff --git a/arch/sparc/include/asm/uaccess.h b/arch/sparc/include/asm/uaccess.h index 42a28cf..20c2acb 100644 --- a/arch/sparc/include/asm/uaccess.h +++ b/arch/sparc/include/asm/uaccess.h @@ -6,6 +6,9 @@ #include #endif +#define user_addr_max() \ + (segment_eq(get_fs(), USER_DS) ? STACK_TOP : ~0UL) + extern long strncpy_from_user(char *dest, const char __user *src, long count); #endif diff --git a/arch/sparc/lib/usercopy.c b/arch/sparc/lib/usercopy.c index 87f9645..f61ed82 100644 --- a/arch/sparc/lib/usercopy.c +++ b/arch/sparc/lib/usercopy.c @@ -3,6 +3,8 @@ #include #include +#include + void copy_from_user_overflow(void) { WARN(1, "Buffer overflow detected!\n"); @@ -14,6 +16,8 @@ EXPORT_SYMBOL(copy_from_user_overflow); static inline long find_zero(unsigned long mask) { long byte = 0; + +#ifdef __BIG_ENDIAN #ifdef CONFIG_64BIT if (mask >> 32) mask >>= 32; @@ -25,8 +29,28 @@ static inline long find_zero(unsigned long mask) else byte += 2; return (mask >> 8) ? byte : byte + 1; +#else +#ifdef CONFIG_64BIT + if (!((unsigned int) mask)) { + mask >>= 32; + byte = 4; + } +#endif + if (!(mask & 0xffff)) { + mask >>= 16; + byte += 2; + } + return (mask & 0xff) ? byte : byte + 1; +#endif } +#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS +#define IS_UNALIGNED(src, dst) 0 +#else +#define IS_UNALIGNED(src, dst) \ + (((long) dst | (long) src) & (sizeof(long) - 1)) +#endif + /* * Do a strncpy, return length of string without final '\0'. * 'count' is the user-supplied count (return 'count' if we @@ -46,7 +70,7 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long if (max > count) max = count; - if (((long) dst | (long) src) & (sizeof(long) - 1)) + if (IS_UNALIGNED(src, dst)) goto byte_at_a_time; while (max >= sizeof(unsigned long)) { @@ -59,7 +83,7 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long v = (c + high_bits) & ~rhs; *(unsigned long *)(dst+res) = c; if (v) { - v = (c & low_bits) + low_bits;; + v = (c & low_bits) + low_bits; v = ~(v | rhs); return res + find_zero(v); } @@ -119,9 +143,7 @@ long strncpy_from_user(char *dst, const char __user *src, long count) if (unlikely(count <= 0)) return 0; - max_addr = ~0UL; - if (likely(segment_eq(get_fs(), USER_DS))) - max_addr = STACK_TOP; + max_addr = user_addr_max(); src_addr = (unsigned long)src; if (likely(src_addr < max_addr)) { unsigned long max = max_addr - src_addr;