sparc: Support atomic64_dec_if_positive properly.

[can-eth-gw-linux.git] / arch / sparc / lib / atomic_64.S

diff --git a/arch/sparc/lib/atomic_64.S b/arch/sparc/lib/atomic_64.S
index 4d502da3de78f2c9e3987a8b7f2ab0f807879201..85c233d0a34003d551587c7c378bd813f64712fe 100644 (file)
--- a/arch/sparc/lib/atomic_64.S
+++ b/arch/sparc/lib/atomic_64.S
@@ -1,6 +1,6 @@
 /* atomic.S: These things are too big to do inline.
  *
- * Copyright (C) 1999, 2007 David S. Miller (davem@davemloft.net)
+ * Copyright (C) 1999, 2007 2012 David S. Miller (davem@davemloft.net)
  */
 
 #include <linux/linkage.h>
@@ -117,3 +117,17 @@ ENTRY(atomic64_sub_ret) /* %o0 = decrement, %o1 = atomic_ptr */
         sub    %g1, %o0, %o0
 2:     BACKOFF_SPIN(%o2, %o3, 1b)
 ENDPROC(atomic64_sub_ret)
+
+ENTRY(atomic64_dec_if_positive) /* %o0 = atomic_ptr */
+       BACKOFF_SETUP(%o2)
+1:     ldx     [%o0], %g1
+       brlez,pn %g1, 3f
+        sub    %g1, 1, %g7
+       casx    [%o0], %g1, %g7
+       cmp     %g1, %g7
+       bne,pn  %xcc, BACKOFF_LABEL(2f, 1b)
+        nop
+3:     retl
+        sub    %g1, 1, %o0
+2:     BACKOFF_SPIN(%o2, %o3, 1b)
+ENDPROC(atomic64_dec_if_positive)