From: Heiko Carstens Date: Tue, 29 May 2012 08:11:21 +0000 (+0200) Subject: s390/cmpxchg: fix 1 and 2 byte memory accesses X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=bf3db85311292eeacc9a9a8f38a0a4065a43a2fc;p=linux-beck.git s390/cmpxchg: fix 1 and 2 byte memory accesses When accessing a 1 or 2 byte memory operand we cannot use the passed address since the compare and swap instruction only works for 4 byte aligned memory operands. Hence we calculate an aligned address so that compare and swap works correctly. However we don't pass the calculated address to the inline assembly. This results in incorrect memory accesses and in a specification exception if used on non 4 byte aligned memory operands. Since this didn't happen until now, there don't seem to be too many users of cmpxchg on unaligned addresses. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- diff --git a/arch/s390/include/asm/cmpxchg.h b/arch/s390/include/asm/cmpxchg.h index 13c8b2eb6983..26f2cb1aa9ff 100644 --- a/arch/s390/include/asm/cmpxchg.h +++ b/arch/s390/include/asm/cmpxchg.h @@ -113,9 +113,9 @@ static inline unsigned long __cmpxchg(void *ptr, unsigned long old, " nr %1,%5\n" " jnz 0b\n" "1:" - : "=&d" (prev), "=&d" (tmp), "=Q" (*(int *) ptr) + : "=&d" (prev), "=&d" (tmp), "+Q" (*(int *) addr) : "d" (old << shift), "d" (new << shift), - "d" (~(255 << shift)), "Q" (*(int *) ptr) + "d" (~(255 << shift)) : "memory", "cc"); return prev >> shift; case 2: @@ -134,9 +134,9 @@ static inline unsigned long __cmpxchg(void *ptr, unsigned long old, " nr %1,%5\n" " jnz 0b\n" "1:" - : "=&d" (prev), "=&d" (tmp), "=Q" (*(int *) ptr) + : "=&d" (prev), "=&d" (tmp), "+Q" (*(int *) addr) : "d" (old << shift), "d" (new << shift), - "d" (~(65535 << shift)), "Q" (*(int *) ptr) + "d" (~(65535 << shift)) : "memory", "cc"); return prev >> shift; case 4: