[SPARC64]: Fix futex_atomic_cmpxchg_inatomic implementation.

I copied the logic from ll/sc arch implementations, but that
was wrong and makes no sense at all.  Just do a straight
compare-exchange instruction, just like x86.

Based upon bug reports from Dennis Gilmore and Fabio Massimo.

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

1 files changed, 8 insertions, 10 deletions

diff --git a/include/asm-sparc64/futex.h b/include/asm-sparc64/futex.h
index dee40206b22..7392fc4a954 100644
--- a/include/asm-sparc64/futex.h
+++ b/include/asm-sparc64/futex.h
@@ -87,24 +87,22 @@ static inline int
 futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
 {
         __asm__ __volatile__(
-        "\n1:   lduwa   [%2] %%asi, %0\n"
-        "2:     casa    [%2] %%asi, %0, %1\n"
-        "3:\n"
+        "\n1:   casa    [%3] %%asi, %2, %0\n"
+        "2:\n"
         "       .section .fixup,#alloc,#execinstr\n"
         "       .align  4\n"
-        "4:     ba      3b\n"
-        "        mov    %3, %0\n"
+        "3:     ba      2b\n"
+        "        mov    %4, %0\n"
         "       .previous\n"
         "       .section __ex_table,\"a\"\n"
         "       .align  4\n"
-        "       .word   1b, 4b\n"
-        "       .word   2b, 4b\n"
+        "       .word   1b, 3b\n"
         "       .previous\n"
-        : "=&r" (oldval)
-        : "r" (newval), "r" (uaddr), "i" (-EFAULT)
+        : "=r" (newval)
+        : "0" (newval), "r" (oldval), "r" (uaddr), "i" (-EFAULT)
         : "memory");
 
-        return oldval;
+        return newval;
 }
 
 #endif /* !(_SPARC64_FUTEX_H) */