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tools arch x86: Introduce atomic_cmpxchg() 

Will be used by atomic_cmpxchg_relaxed(), in turn used by refcount.h.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-kdmovd3l4gw5b1w31ypr6ddv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2017-02-22 16:55:43 -03:00
parent 3337e682d9
commit 8a73615df3
1 changed files with 7 additions and 0 deletions
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7
tools/arch/x86/include/asm/atomic.h
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@ -7,6 +7,8 @@
#define LOCK_PREFIX "\n\tlock; "
#include <asm/cmpxchg.h>
/*
* Atomic operations that C can't guarantee us. Useful for
* resource counting etc..
@ -62,4 +64,9 @@ static inline int atomic_dec_and_test(atomic_t *v)
GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, "%0", "e");
}
static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new)
{
return cmpxchg(&v->counter, old, new);
}
#endif /* _TOOLS_LINUX_ASM_X86_ATOMIC_H */