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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) <peterz@infradead.org>
Acked-by: James Hogan <james.hogan@imgtec.com>
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: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-metag@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2016-04-18 01:16:06 +02:00 committed by Ingo Molnar
parent e39d88ea3c
commit e898eb27ff
3 changed files with 63 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/metag/include/asm/atomic.h
View File

@ -17,6 +17,8 @@
#include <asm/atomic_lnkget.h>
#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))

36
arch/metag/include/asm/atomic_lnkget.h
View File

@ -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

33
arch/metag/include/asm/atomic_lock1.h
View File

@ -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