From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: [PATCH] alpha: spinlock: don't perform memory access in locked critical section Date: Mon, 6 May 2013 21:01:05 +0100 Message-ID: <1367870465-23948-1-git-send-email-will.deacon@arm.com> Return-path: Sender: linux-alpha-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-alpha@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Will Deacon , Richard Henderson , Ivan Kokshaysky , Matt Turner The Alpha Architecture Reference Manual states that any memory access performed between an LD_xL and a STx_C instruction may cause the store-conditional to fail unconditionally and, as such, `no useful program should do this'. Linux is a useful program, so fix up the Alpha spinlock implementation to use logical operations rather than load-address instructions for generating immediates. Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Signed-off-by: Will Deacon --- arch/alpha/include/asm/spinlock.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/alpha/include/asm/spinlock.h b/arch/alpha/include/asm/spinlock.h index 3bba21e..0c357cd 100644 --- a/arch/alpha/include/asm/spinlock.h +++ b/arch/alpha/include/asm/spinlock.h @@ -29,7 +29,7 @@ static inline void arch_spin_lock(arch_spinlock_t * lock) __asm__ __volatile__( "1: ldl_l %0,%1\n" " bne %0,2f\n" - " lda %0,1\n" + " mov 1,%0\n" " stl_c %0,%1\n" " beq %0,2f\n" " mb\n" @@ -86,7 +86,7 @@ static inline void arch_write_lock(arch_rwlock_t *lock) __asm__ __volatile__( "1: ldl_l %1,%0\n" " bne %1,6f\n" - " lda %1,1\n" + " mov 1,%1\n" " stl_c %1,%0\n" " beq %1,6f\n" " mb\n" @@ -106,7 +106,7 @@ static inline int arch_read_trylock(arch_rwlock_t * lock) __asm__ __volatile__( "1: ldl_l %1,%0\n" - " lda %2,0\n" + " mov 0,%2\n" " blbs %1,2f\n" " subl %1,2,%2\n" " stl_c %2,%0\n" @@ -128,9 +128,9 @@ static inline int arch_write_trylock(arch_rwlock_t * lock) __asm__ __volatile__( "1: ldl_l %1,%0\n" - " lda %2,0\n" + " mov 0,%2\n" " bne %1,2f\n" - " lda %2,1\n" + " mov 1,%2\n" " stl_c %2,%0\n" " beq %2,6f\n" "2: mb\n" -- 1.8.2.2