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locking/atomic, arch/alpha: Implement atomic{,64}_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>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-alpha@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2016-04-18 01:16:10 +02:00 committed by Ingo Molnar
parent b316ff783d
commit 1f51dee7ca
1 changed files with 56 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

65
arch/alpha/include/asm/atomic.h
View File

@ -65,6 +65,25 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \
return result; \
}
#define ATOMIC_FETCH_OP(op, asm_op) \
static inline int atomic_fetch_##op(int i, atomic_t *v) \
{ \
long temp, result; \
smp_mb(); \
__asm__ __volatile__( \
"1: ldl_l %2,%1\n" \
" " #asm_op " %2,%3,%0\n" \
" stl_c %0,%1\n" \
" beq %0,2f\n" \
".subsection 2\n" \
"2: br 1b\n" \
".previous" \
:"=&r" (temp), "=m" (v->counter), "=&r" (result) \
:"Ir" (i), "m" (v->counter) : "memory"); \
smp_mb(); \
return result; \
}
#define ATOMIC64_OP(op, asm_op) \
static __inline__ void atomic64_##op(long i, atomic64_t * v) \
{ \
@ -101,11 +120,32 @@ static __inline__ long atomic64_##op##_return(long i, atomic64_t * v) \
return result; \
}
#define ATOMIC64_FETCH_OP(op, asm_op) \
static __inline__ long atomic64_fetch_##op(long i, atomic64_t * v) \
{ \
long temp, result; \
smp_mb(); \
__asm__ __volatile__( \
"1: ldq_l %2,%1\n" \
" " #asm_op " %2,%3,%0\n" \
" stq_c %0,%1\n" \
" beq %0,2f\n" \
".subsection 2\n" \
"2: br 1b\n" \
".previous" \
:"=&r" (temp), "=m" (v->counter), "=&r" (result) \
:"Ir" (i), "m" (v->counter) : "memory"); \
smp_mb(); \
return result; \
}
#define ATOMIC_OPS(op) \
ATOMIC_OP(op, op##l) \
ATOMIC_OP_RETURN(op, op##l) \
ATOMIC_FETCH_OP(op, op##l) \
ATOMIC64_OP(op, op##q) \
ATOMIC64_OP_RETURN(op, op##q)
ATOMIC64_OP_RETURN(op, op##q) \
ATOMIC64_FETCH_OP(op, op##q)
ATOMIC_OPS(add)
ATOMIC_OPS(sub)
@ -113,18 +153,25 @@ ATOMIC_OPS(sub)
#define atomic_andnot atomic_andnot
#define atomic64_andnot atomic64_andnot
ATOMIC_OP(and, and)
ATOMIC_OP(andnot, bic)
ATOMIC_OP(or, bis)
ATOMIC_OP(xor, xor)
ATOMIC64_OP(and, and)
ATOMIC64_OP(andnot, bic)
ATOMIC64_OP(or, bis)
ATOMIC64_OP(xor, xor)
#define atomic_fetch_or atomic_fetch_or
#undef ATOMIC_OPS
#define ATOMIC_OPS(op, asm) \
ATOMIC_OP(op, asm) \
ATOMIC_FETCH_OP(op, asm) \
ATOMIC64_OP(op, asm) \
ATOMIC64_FETCH_OP(op, asm)
ATOMIC_OPS(and, and)
ATOMIC_OPS(andnot, bic)
ATOMIC_OPS(or, bis)
ATOMIC_OPS(xor, xor)
#undef ATOMIC_OPS
#undef ATOMIC64_FETCH_OP
#undef ATOMIC64_OP_RETURN
#undef ATOMIC64_OP
#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
#undef ATOMIC_OP