From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: [PATCH 1/3] sparc: Increase portability of strncpy_from_user() implementation. Date: Wed, 23 May 2012 23:34:30 -0400 (EDT) Message-ID: <20120523.233430.1084831063018998232.davem@davemloft.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from shards.monkeyblade.net ([198.137.202.13]:35989 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932116Ab2EXDec (ORCPT ); Wed, 23 May 2012 23:34:32 -0400 Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-arch@vger.kernel.org Cc: torvalds@linux-foundation.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. Guard alignment check using CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS. Signed-off-by: David S. Miller --- arch/sparc/include/asm/uaccess.h | 3 +++ arch/sparc/lib/usercopy.c | 28 ++++++++++++++++++++++------ 2 files changed, 25 insertions(+), 6 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..9ba59ef 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; @@ -25,6 +29,19 @@ 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 } /* @@ -45,10 +62,10 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long */ if (max > count) max = count; - +#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS if (((long) dst | (long) src) & (sizeof(long) - 1)) goto byte_at_a_time; - +#endif while (max >= sizeof(unsigned long)) { unsigned long c, v, rhs; @@ -66,8 +83,9 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long res += sizeof(unsigned long); max -= sizeof(unsigned long); } - +#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS byte_at_a_time: +#endif while (max) { char c; @@ -119,9 +137,7 @@ 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; -- 1.7.10