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| author | Peter Zijlstra <peterz@infradead.org> | 2016-04-18 01:16:09 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-16 10:48:20 +0200 |
| commit | fbffe892e5253dd02c016c59a9d792eafe9d53e1 (patch) | |
| tree | 668ef1af920c73d04fac72baf07a817d65d14a5a /arch/arc/include | |
| parent | locking/atomic, arch/alpha: Implement atomic{,64}_fetch_{add,sub,and,andnot,o... (diff) | |
| download | linux-fbffe892e5253dd02c016c59a9d792eafe9d53e1.tar.xz linux-fbffe892e5253dd02c016c59a9d792eafe9d53e1.zip | |
locking/atomic, arch/arc: Implement atomic_fetch_{add,sub,and,andnot,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>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Noam Camus <noamc@ezchip.com>
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
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/arc/include')
| -rw-r--r-- | arch/arc/include/asm/atomic.h | 103 |
1 files changed, 94 insertions, 9 deletions
diff --git a/arch/arc/include/asm/atomic.h b/arch/arc/include/asm/atomic.h index dd683995bc9d..c066a21caaaf 100644 --- a/arch/arc/include/asm/atomic.h +++ b/arch/arc/include/asm/atomic.h @@ -67,6 +67,37 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ return val; \ } +#define ATOMIC_FETCH_OP(op, c_op, asm_op) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + unsigned int val, orig; \ + SCOND_FAIL_RETRY_VAR_DEF \ + \ + /* \ + * Explicit full memory barrier needed before/after as \ + * LLOCK/SCOND thmeselves don't provide any such semantics \ + */ \ + smp_mb(); \ + \ + __asm__ __volatile__( \ + "1: llock %[orig], [%[ctr]] \n" \ + " " #asm_op " %[val], %[orig], %[i] \n" \ + " scond %[val], [%[ctr]] \n" \ + " \n" \ + SCOND_FAIL_RETRY_ASM \ + \ + : [val] "=&r" (val), \ + [orig] "=&r" (orig) \ + SCOND_FAIL_RETRY_VARS \ + : [ctr] "r" (&v->counter), \ + [i] "ir" (i) \ + : "cc"); \ + \ + smp_mb(); \ + \ + return orig; \ +} + #else /* !CONFIG_ARC_HAS_LLSC */ #ifndef CONFIG_SMP @@ -129,21 +160,46 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ return temp; \ } +#define ATOMIC_FETCH_OP(op, c_op, asm_op) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + unsigned long flags; \ + unsigned long orig; \ + \ + /* \ + * spin lock/unlock provides the needed smp_mb() before/after \ + */ \ + atomic_ops_lock(flags); \ + orig = v->counter; \ + v->counter c_op i; \ + atomic_ops_unlock(flags); \ + \ + return orig; \ +} + #endif /* !CONFIG_ARC_HAS_LLSC */ #define ATOMIC_OPS(op, c_op, asm_op) \ ATOMIC_OP(op, c_op, asm_op) \ - ATOMIC_OP_RETURN(op, c_op, asm_op) + ATOMIC_OP_RETURN(op, c_op, asm_op) \ + ATOMIC_FETCH_OP(op, c_op, asm_op) ATOMIC_OPS(add, +=, add) ATOMIC_OPS(sub, -=, sub) #define atomic_andnot atomic_andnot -ATOMIC_OP(and, &=, and) -ATOMIC_OP(andnot, &= ~, bic) -ATOMIC_OP(or, |=, or) -ATOMIC_OP(xor, ^=, xor) +#define atomic_fetch_or atomic_fetch_or + +#undef ATOMIC_OPS +#define ATOMIC_OPS(op, c_op, asm_op) \ + ATOMIC_OP(op, c_op, asm_op) \ + ATOMIC_FETCH_OP(op, c_op, asm_op) + +ATOMIC_OPS(and, &=, and) +ATOMIC_OPS(andnot, &= ~, bic) +ATOMIC_OPS(or, |=, or) +ATOMIC_OPS(xor, ^=, xor) #undef SCOND_FAIL_RETRY_VAR_DEF #undef SCOND_FAIL_RETRY_ASM @@ -208,22 +264,51 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ return temp; \ } +#define ATOMIC_FETCH_OP(op, c_op, asm_op) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ +{ \ + unsigned int temp = i; \ + \ + /* Explicit full memory barrier needed before/after */ \ + smp_mb(); \ + \ + __asm__ __volatile__( \ + " mov r2, %0\n" \ + " mov r3, %1\n" \ + " .word %2\n" \ + " mov %0, r2" \ + : "+r"(temp) \ + : "r"(&v->counter), "i"(asm_op) \ + : "r2", "r3", "memory"); \ + \ + smp_mb(); \ + \ + return temp; \ +} + #define ATOMIC_OPS(op, c_op, asm_op) \ ATOMIC_OP(op, c_op, asm_op) \ - ATOMIC_OP_RETURN(op, c_op, asm_op) + ATOMIC_OP_RETURN(op, c_op, asm_op) \ + ATOMIC_FETCH_OP(op, c_op, asm_op) ATOMIC_OPS(add, +=, CTOP_INST_AADD_DI_R2_R2_R3) #define atomic_sub(i, v) atomic_add(-(i), (v)) #define atomic_sub_return(i, v) atomic_add_return(-(i), (v)) -ATOMIC_OP(and, &=, CTOP_INST_AAND_DI_R2_R2_R3) +#undef ATOMIC_OPS +#define ATOMIC_OPS(op, c_op, asm_op) \ + ATOMIC_OP(op, c_op, asm_op) \ + ATOMIC_FETCH_OP(op, c_op, asm_op) + +ATOMIC_OPS(and, &=, CTOP_INST_AAND_DI_R2_R2_R3) #define atomic_andnot(mask, v) atomic_and(~(mask), (v)) -ATOMIC_OP(or, |=, CTOP_INST_AOR_DI_R2_R2_R3) -ATOMIC_OP(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3) +ATOMIC_OPS(or, |=, CTOP_INST_AOR_DI_R2_R2_R3) +ATOMIC_OPS(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3) #endif /* CONFIG_ARC_PLAT_EZNPS */ #undef ATOMIC_OPS +#undef ATOMIC_FETCH_OP #undef ATOMIC_OP_RETURN #undef ATOMIC_OP |