From e898eb27ffd8b0ad6f4fd0b631559bc877c85444 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 18 Apr 2016 01:16:06 +0200 Subject: [PATCH] locking/atomic, arch/metag: 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) Acked-by: James Hogan Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-metag@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/metag/include/asm/atomic.h | 2 ++ arch/metag/include/asm/atomic_lnkget.h | 36 ++++++++++++++++++++++++++++++---- arch/metag/include/asm/atomic_lock1.h | 33 +++++++++++++++++++++++++++---- 3 files changed, 63 insertions(+), 8 deletions(-) diff --git a/arch/metag/include/asm/atomic.h b/arch/metag/include/asm/atomic.h index 470e365..6ca210d 100644 --- a/arch/metag/include/asm/atomic.h +++ b/arch/metag/include/asm/atomic.h @@ -17,6 +17,8 @@ #include #endif +#define atomic_fetch_or atomic_fetch_or + #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0) #define atomic_dec_return(v) atomic_sub_return(1, (v)) diff --git a/arch/metag/include/asm/atomic_lnkget.h b/arch/metag/include/asm/atomic_lnkget.h index 88fa25f..def2c64 100644 --- a/arch/metag/include/asm/atomic_lnkget.h +++ b/arch/metag/include/asm/atomic_lnkget.h @@ -69,16 +69,44 @@ 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) \ +{ \ + int result, temp; \ + \ + smp_mb(); \ + \ + asm volatile ( \ + "1: LNKGETD %1, [%2]\n" \ + " " #op " %0, %1, %3\n" \ + " LNKSETD [%2], %0\n" \ + " DEFR %0, TXSTAT\n" \ + " ANDT %0, %0, #HI(0x3f000000)\n" \ + " CMPT %0, #HI(0x02000000)\n" \ + " BNZ 1b\n" \ + : "=&d" (temp), "=&d" (result) \ + : "da" (&v->counter), "bd" (i) \ + : "cc"); \ + \ + smp_mb(); \ + \ + 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) + +ATOMIC_OPS(and) +ATOMIC_OPS(or) +ATOMIC_OPS(xor) #undef ATOMIC_OPS +#undef ATOMIC_FETCH_OP #undef ATOMIC_OP_RETURN #undef ATOMIC_OP diff --git a/arch/metag/include/asm/atomic_lock1.h b/arch/metag/include/asm/atomic_lock1.h index 0295d9b..6c1380a 100644 --- a/arch/metag/include/asm/atomic_lock1.h +++ b/arch/metag/include/asm/atomic_lock1.h @@ -64,15 +64,40 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ return result; \ } -#define ATOMIC_OPS(op, c_op) ATOMIC_OP(op, c_op) ATOMIC_OP_RETURN(op, c_op) +#define ATOMIC_FETCH_OP(op, c_op) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + unsigned long result; \ + unsigned long flags; \ + \ + __global_lock1(flags); \ + result = v->counter; \ + fence(); \ + v->counter c_op i; \ + __global_unlock1(flags); \ + \ + return result; \ +} + +#define ATOMIC_OPS(op, c_op) \ + ATOMIC_OP(op, c_op) \ + ATOMIC_OP_RETURN(op, c_op) \ + ATOMIC_FETCH_OP(op, c_op) ATOMIC_OPS(add, +=) ATOMIC_OPS(sub, -=) -ATOMIC_OP(and, &=) -ATOMIC_OP(or, |=) -ATOMIC_OP(xor, ^=) #undef ATOMIC_OPS +#define ATOMIC_OPS(op, c_op) \ + ATOMIC_OP(op, c_op) \ + ATOMIC_FETCH_OP(op, c_op) + +ATOMIC_OPS(and, &=) +ATOMIC_OPS(or, |=) +ATOMIC_OPS(xor, ^=) + +#undef ATOMIC_OPS +#undef ATOMIC_FETCH_OP #undef ATOMIC_OP_RETURN #undef ATOMIC_OP -- 2.7.4