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| author | Peter Zijlstra <peterz@infradead.org> | 2016-04-17 23:16:07 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-16 08:48:25 (GMT) |
| commit | f649370523033c7c2adf16a9d062438c8a7758b3 (patch) | |
| tree | 671dd5b1d9354e91053521dd29ad90f3f05c80a9 | |
| parent | cc102507fac75f9f4f37938f49d10c25e596a608 (diff) | |
| download | linux-f649370523033c7c2adf16a9d062438c8a7758b3.tar.xz | |
locking/atomic, arch/m32r: Implement atomic_fetch_{add,sub,and,or,xor}()
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>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/m32r/include/asm/atomic.h | 38 |
1 files changed, 34 insertions, 4 deletions
diff --git a/arch/m32r/include/asm/atomic.h b/arch/m32r/include/asm/atomic.h index ea35160..8ba8a0a 100644 --- a/arch/m32r/include/asm/atomic.h +++ b/arch/m32r/include/asm/atomic.h @@ -89,16 +89,46 @@ static __inline__ int atomic_##op##_return(int i, atomic_t *v) \ 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 |