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locking/atomic, arch/mn10300: 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: David Howells <dhowells@redhat.com>
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-am33-list@redhat.com
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 01:16:05 +02:00 committed by Ingo Molnar
parent 4edac529eb
commit f8d638e28d
1 changed files with 31 additions and 4 deletions
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35
arch/mn10300/include/asm/atomic.h
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@ -84,16 +84,43 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \
return retval; \
}
#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 retval, status; \
\
asm volatile( \
"1: mov %4,(_AAR,%3) \n" \
" mov (_ADR,%3),%1 \n" \
" mov %1,%0 \n" \
" " #op " %5,%0 \n" \
" mov %0,(_ADR,%3) \n" \
" mov (_ADR,%3),%0 \n" /* flush */ \
" mov (_ASR,%3),%0 \n" \
" or %0,%0 \n" \
" bne 1b \n" \
: "=&r"(status), "=&r"(retval), "=m"(v->counter) \
: "a"(ATOMIC_OPS_BASE_ADDR), "r"(&v->counter), "r"(i) \
: "memory", "cc"); \
return retval; \
}
#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