diff options
Diffstat (limited to 'arch/arc/include/asm/atomic.h')
| -rw-r--r-- | arch/arc/include/asm/atomic.h | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h index 9917a45fc430..03484cb4d16d 100644 --- a/arch/arc/include/asm/atomic.h +++ b/arch/arc/include/asm/atomic.h @@ -23,13 +23,21 @@ #define atomic_set(v, i) (((v)->counter) = (i)) +#ifdef CONFIG_ISA_ARCV2 +#define PREFETCHW " prefetchw [%1] \n" +#else +#define PREFETCHW +#endif + #define ATOMIC_OP(op, c_op, asm_op) \ static inline void atomic_##op(int i, atomic_t *v) \ { \ unsigned int temp; \ \ __asm__ __volatile__( \ - "1: llock %0, [%1] \n" \ + "1: \n" \ + PREFETCHW \ + " llock %0, [%1] \n" \ " " #asm_op " %0, %0, %2 \n" \ " scond %0, [%1] \n" \ " bnz 1b \n" \ @@ -43,8 +51,16 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ { \ unsigned int temp; \ \ + /* \ + * Explicit full memory barrier needed before/after as \ + * LLOCK/SCOND thmeselves don't provide any such semantics \ + */ \ + smp_mb(); \ + \ __asm__ __volatile__( \ - "1: llock %0, [%1] \n" \ + "1: \n" \ + PREFETCHW \ + " llock %0, [%1] \n" \ " " #asm_op " %0, %0, %2 \n" \ " scond %0, [%1] \n" \ " bnz 1b \n" \ @@ -52,6 +68,8 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ : "r"(&v->counter), "ir"(i) \ : "cc"); \ \ + smp_mb(); \ + \ return temp; \ } @@ -105,6 +123,9 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ unsigned long flags; \ unsigned long temp; \ \ + /* \ + * spin lock/unlock provides the needed smp_mb() before/after \ + */ \ atomic_ops_lock(flags); \ temp = v->counter; \ temp c_op i; \ @@ -142,9 +163,19 @@ ATOMIC_OP(and, &=, and) #define __atomic_add_unless(v, a, u) \ ({ \ int c, old; \ + \ + /* \ + * Explicit full memory barrier needed before/after as \ + * LLOCK/SCOND thmeselves don't provide any such semantics \ + */ \ + smp_mb(); \ + \ c = atomic_read(v); \ while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c)\ c = old; \ + \ + smp_mb(); \ + \ c; \ }) |
