| From afa31d8eb86fc2f25083e675d57ac8173a98f999 Mon Sep 17 00:00:00 2001 |
| From: Will Deacon <will.deacon@arm.com> |
| Date: Mon, 12 Aug 2013 18:03:26 +0100 |
| Subject: ARM: 7811/1: locks: use early clobber in arch_spin_trylock |
| |
| From: Will Deacon <will.deacon@arm.com> |
| |
| commit afa31d8eb86fc2f25083e675d57ac8173a98f999 upstream. |
| |
| The res variable is written before we've finished with the input |
| operands (namely the lock address), so ensure that we mark it as `early |
| clobber' to avoid unintended register sharing. |
| |
| Signed-off-by: Will Deacon <will.deacon@arm.com> |
| Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> |
| Cc: Wang Weidong <wangweidong1@huawei.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/arm/include/asm/spinlock.h | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/arch/arm/include/asm/spinlock.h |
| +++ b/arch/arm/include/asm/spinlock.h |
| @@ -107,7 +107,7 @@ static inline int arch_spin_trylock(arch |
| " subs %1, %0, %0, ror #16\n" |
| " addeq %0, %0, %4\n" |
| " strexeq %2, %0, [%3]" |
| - : "=&r" (slock), "=&r" (contended), "=r" (res) |
| + : "=&r" (slock), "=&r" (contended), "=&r" (res) |
| : "r" (&lock->slock), "I" (1 << TICKET_SHIFT) |
| : "cc"); |
| } while (res); |
