x86: replace futex_atomic_cmpxchg_inatomic() with user_atomic_cmpxchg_inatomic

qwren · H. Peter Anvin · commit 0ee3b6f87d4d · 2013-12-16T09:08:13.000-08:00
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>
diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h
@@ -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
