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| author | Peter Zijlstra <peterz@infradead.org> | 2016-04-18 01:16:07 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-16 10:48:25 +0200 |
| commit | 4be7dd393515615430a4d07ca1ffceaf2a331620 (patch) | |
| tree | a69d51f7059eae1a168f58aca3f853ddbf755c54 | |
| parent | locking/atomic, arch/h8300: Implement atomic_fetch_{add,sub,and,or,xor}() (diff) | |
| download | linux-4be7dd393515615430a4d07ca1ffceaf2a331620.tar.xz linux-4be7dd393515615430a4d07ca1ffceaf2a331620.zip | |
locking/atomic, arch/hexagon: 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: Richard Kuo <rkuo@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-hexagon@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/hexagon/include/asm/atomic.h | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/arch/hexagon/include/asm/atomic.h b/arch/hexagon/include/asm/atomic.h index 55696c4100d4..07dbb3332b4a 100644 --- a/arch/hexagon/include/asm/atomic.h +++ b/arch/hexagon/include/asm/atomic.h @@ -110,7 +110,7 @@ static inline void atomic_##op(int i, atomic_t *v) \ ); \ } \ -#define ATOMIC_OP_RETURN(op) \ +#define ATOMIC_OP_RETURN(op) \ static inline int atomic_##op##_return(int i, atomic_t *v) \ { \ int output; \ @@ -127,16 +127,39 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ return output; \ } -#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) \ +{ \ + int output, val; \ + \ + __asm__ __volatile__ ( \ + "1: %0 = memw_locked(%2);\n" \ + " %1 = "#op "(%0,%3);\n" \ + " memw_locked(%2,P3)=%1;\n" \ + " if !P3 jump 1b;\n" \ + : "=&r" (output), "=&r" (val) \ + : "r" (&v->counter), "r" (i) \ + : "memory", "p3" \ + ); \ + return output; \ +} + +#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 |