[PATCH -v2 13/33] locking,m32r: Implement atomic_fetch_{add,sub,and,or,xor}()
From: Peter Zijlstra <peterz@infradead.org>
Date: 2016-05-31 10:30:09
Also in:
lkml
Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- arch/m32r/include/asm/atomic.h | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-)
--- a/arch/m32r/include/asm/atomic.h
+++ b/arch/m32r/include/asm/atomic.h@@ -89,16 +89,46 @@ static __inline__ int atomic_##op##_retu return result; \ } -#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) +#define ATOMIC_FETCH_OP(op) \ +static __inline__ int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + unsigned long flags; \ + int result, val; \ + \ + local_irq_save(flags); \ + __asm__ __volatile__ ( \ + "# atomic_fetch_" #op " \n\t" \ + DCACHE_CLEAR("%0", "r4", "%2") \ + M32R_LOCK" %1, @%2; \n\t" \ + "mv %0, %1 \n\t" \ + #op " %1, %3; \n\t" \ + M32R_UNLOCK" %1, @%2; \n\t" \ + : "=&r" (result), "=&r" (val) \ + : "r" (&v->counter), "r" (i) \ + : "memory" \ + __ATOMIC_CLOBBER \ + ); \ + local_irq_restore(flags); \ + \ + return result; \ +} + +#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) ATOMIC_FETCH_OP(op) ATOMIC_OPS(add) ATOMIC_OPS(sub) -ATOMIC_OP(and) -ATOMIC_OP(or) -ATOMIC_OP(xor) +#undef ATOMIC_OPS +#define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_FETCH_OP(op) + +#define atomic_fetch_or atomic_fetch_or + +ATOMIC_OPS(and) +ATOMIC_OPS(or) +ATOMIC_OPS(xor) #undef ATOMIC_OPS +#undef ATOMIC_FETCH_OP #undef ATOMIC_OP_RETURN #undef ATOMIC_OP