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ARM: 7811/1: locks: use early clobber in arch_spin_trylock

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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>
This commit is contained in:
Will Deacon 2013-08-12 18:03:26 +01:00 committed by Russell King
parent e35ac62d22
commit afa31d8eb8
1 changed files with 1 additions and 1 deletions
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2
arch/arm/include/asm/spinlock.h
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@ -107,7 +107,7 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock)
" 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);