| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 28/85] ARM: 7811/1: locks: use early clobber in arch_spin_trylock | Date | Thu, 20 Mar 2014 17:09:31 -0700 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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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);
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