From 3a0310eb369aae985d6409d8ff1340146578e5c1 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 4 Feb 2013 12:12:33 +0000 Subject: arm64: atomics: fix grossly inconsistent asm constraints for exclusives Our uses of inline asm constraints for atomic operations are fairly wild and varied. We basically need to guarantee the following: 1. Any instructions with barrier implications (load-acquire/store-release) have a "memory" clobber 2. When performing exclusive accesses, the addresing mode is generated using the "Q" constraint 3. Atomic blocks which use the condition flags, have a "cc" clobber This patch addresses these concerns which, as well as fixing the semantics of the code, stops GCC complaining about impossible asm constraints. Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/spinlock.h | 78 +++++++++++++++++++-------------------- 1 file changed, 39 insertions(+), 39 deletions(-) (limited to 'arch/arm64/include/asm/spinlock.h') diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h index 41112fe2f8b1..7065e920149d 100644 --- a/arch/arm64/include/asm/spinlock.h +++ b/arch/arm64/include/asm/spinlock.h @@ -45,13 +45,13 @@ static inline void arch_spin_lock(arch_spinlock_t *lock) asm volatile( " sevl\n" "1: wfe\n" - "2: ldaxr %w0, [%1]\n" + "2: ldaxr %w0, %1\n" " cbnz %w0, 1b\n" - " stxr %w0, %w2, [%1]\n" + " stxr %w0, %w2, %1\n" " cbnz %w0, 2b\n" - : "=&r" (tmp) - : "r" (&lock->lock), "r" (1) - : "memory"); + : "=&r" (tmp), "+Q" (lock->lock) + : "r" (1) + : "cc", "memory"); } static inline int arch_spin_trylock(arch_spinlock_t *lock) @@ -59,13 +59,13 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock) unsigned int tmp; asm volatile( - " ldaxr %w0, [%1]\n" + " ldaxr %w0, %1\n" " cbnz %w0, 1f\n" - " stxr %w0, %w2, [%1]\n" + " stxr %w0, %w2, %1\n" "1:\n" - : "=&r" (tmp) - : "r" (&lock->lock), "r" (1) - : "memory"); + : "=&r" (tmp), "+Q" (lock->lock) + : "r" (1) + : "cc", "memory"); return !tmp; } @@ -73,8 +73,8 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock) static inline void arch_spin_unlock(arch_spinlock_t *lock) { asm volatile( - " stlr %w1, [%0]\n" - : : "r" (&lock->lock), "r" (0) : "memory"); + " stlr %w1, %0\n" + : "=Q" (lock->lock) : "r" (0) : "memory"); } /* @@ -94,13 +94,13 @@ static inline void arch_write_lock(arch_rwlock_t *rw) asm volatile( " sevl\n" "1: wfe\n" - "2: ldaxr %w0, [%1]\n" + "2: ldaxr %w0, %1\n" " cbnz %w0, 1b\n" - " stxr %w0, %w2, [%1]\n" + " stxr %w0, %w2, %1\n" " cbnz %w0, 2b\n" - : "=&r" (tmp) - : "r" (&rw->lock), "r" (0x80000000) - : "memory"); + : "=&r" (tmp), "+Q" (rw->lock) + : "r" (0x80000000) + : "cc", "memory"); } static inline int arch_write_trylock(arch_rwlock_t *rw) @@ -108,13 +108,13 @@ static inline int arch_write_trylock(arch_rwlock_t *rw) unsigned int tmp; asm volatile( - " ldaxr %w0, [%1]\n" + " ldaxr %w0, %1\n" " cbnz %w0, 1f\n" - " stxr %w0, %w2, [%1]\n" + " stxr %w0, %w2, %1\n" "1:\n" - : "=&r" (tmp) - : "r" (&rw->lock), "r" (0x80000000) - : "memory"); + : "=&r" (tmp), "+Q" (rw->lock) + : "r" (0x80000000) + : "cc", "memory"); return !tmp; } @@ -122,8 +122,8 @@ static inline int arch_write_trylock(arch_rwlock_t *rw) static inline void arch_write_unlock(arch_rwlock_t *rw) { asm volatile( - " stlr %w1, [%0]\n" - : : "r" (&rw->lock), "r" (0) : "memory"); + " stlr %w1, %0\n" + : "=Q" (rw->lock) : "r" (0) : "memory"); } /* write_can_lock - would write_trylock() succeed? */ @@ -148,14 +148,14 @@ static inline void arch_read_lock(arch_rwlock_t *rw) asm volatile( " sevl\n" "1: wfe\n" - "2: ldaxr %w0, [%2]\n" + "2: ldaxr %w0, %2\n" " add %w0, %w0, #1\n" " tbnz %w0, #31, 1b\n" - " stxr %w1, %w0, [%2]\n" + " stxr %w1, %w0, %2\n" " cbnz %w1, 2b\n" - : "=&r" (tmp), "=&r" (tmp2) - : "r" (&rw->lock) - : "memory"); + : "=&r" (tmp), "=&r" (tmp2), "+Q" (rw->lock) + : + : "cc", "memory"); } static inline void arch_read_unlock(arch_rwlock_t *rw) @@ -163,13 +163,13 @@ static inline void arch_read_unlock(arch_rwlock_t *rw) unsigned int tmp, tmp2; asm volatile( - "1: ldxr %w0, [%2]\n" + "1: ldxr %w0, %2\n" " sub %w0, %w0, #1\n" - " stlxr %w1, %w0, [%2]\n" + " stlxr %w1, %w0, %2\n" " cbnz %w1, 1b\n" - : "=&r" (tmp), "=&r" (tmp2) - : "r" (&rw->lock) - : "memory"); + : "=&r" (tmp), "=&r" (tmp2), "+Q" (rw->lock) + : + : "cc", "memory"); } static inline int arch_read_trylock(arch_rwlock_t *rw) @@ -177,14 +177,14 @@ static inline int arch_read_trylock(arch_rwlock_t *rw) unsigned int tmp, tmp2 = 1; asm volatile( - " ldaxr %w0, [%2]\n" + " ldaxr %w0, %2\n" " add %w0, %w0, #1\n" " tbnz %w0, #31, 1f\n" - " stxr %w1, %w0, [%2]\n" + " stxr %w1, %w0, %2\n" "1:\n" - : "=&r" (tmp), "+r" (tmp2) - : "r" (&rw->lock) - : "memory"); + : "=&r" (tmp), "+r" (tmp2), "+Q" (rw->lock) + : + : "cc", "memory"); return !tmp2; } -- cgit v1.2.3-59-g8ed1b