[SPARC64]: Implement futex_atomic_cmpxchg_inatomic().

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 2 deletions

diff --git a/include/asm-sparc64/futex.h b/include/asm-sparc64/futex.h
index cd340a233156..dee40206b221 100644
--- a/include/asm-sparc64/futex.h
+++ b/include/asm-sparc64/futex.h
@@ -84,9 +84,27 @@ static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
 }
 
 static inline int
-futex_atomic_cmpxchg_inuser(int __user *uaddr, int oldval, int newval)
+futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
 {
-        return -ENOSYS;
+        __asm__ __volatile__(
+        "\n1:   lduwa   [%2] %%asi, %0\n"
+        "2:     casa    [%2] %%asi, %0, %1\n"
+        "3:\n"
+        "       .section .fixup,#alloc,#execinstr\n"
+        "       .align  4\n"
+        "4:     ba      3b\n"
+        "        mov    %3, %0\n"
+        "       .previous\n"
+        "       .section __ex_table,\"a\"\n"
+        "       .align  4\n"
+        "       .word   1b, 4b\n"
+        "       .word   2b, 4b\n"
+        "       .previous\n"
+        : "=&r" (oldval)
+        : "r" (newval), "r" (uaddr), "i" (-EFAULT)
+        : "memory");
+
+        return oldval;
 }
 
 #endif /* !(_SPARC64_FUTEX_H) */