Commit 0ee3b6f8 authored Dec 14, 2013 by Qiaowei Ren Committed by H. Peter Anvin Dec 16, 2013

x86: replace futex_atomic_cmpxchg_inatomic() with user_atomic_cmpxchg_inatomic



futex_atomic_cmpxchg_inatomic() is simply the 32-bit implementation of
user_atomic_cmpxchg_inatomic(), which in turn is simply a
generalization of the original code in
futex_atomic_cmpxchg_inatomic().

Use the newly generalized user_atomic_cmpxchg_inatomic() as the futex
implementation, too.

[ hpa: retain the inline in futex.h rather than changing it to a macro ]

Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
Link: http://lkml.kernel.org/r/1387002303-6620-2-git-send-email-qiaowei.ren@intel.com


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>

parent f09174c5

arch/x86/include/asm/futex.h

+1 −20

Original line number	Diff line number	Diff line
		@@ -110,26 +110,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
		static inline int futex_atomic_cmpxchg_inatomic(u32 uval, u32 __user uaddr,
		u32 oldval, u32 newval)
		{
		int ret = 0;

		if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
		return -EFAULT;

		asm volatile("\t" ASM_STAC "\n"
		"1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"
		"2:\t" ASM_CLAC "\n"
		"\t.section .fixup, \"ax\"\n"
		"3:\tmov %3, %0\n"
		"\tjmp 2b\n"
		"\t.previous\n"
		_ASM_EXTABLE(1b, 3b)
		: "+r" (ret), "=a" (oldval), "+m" (*uaddr)
		: "i" (-EFAULT), "r" (newval), "1" (oldval)
		: "memory"
		);

		*uval = oldval;
		return ret;
		return user_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval);
		}

		#endif