[PATCH 4.1 077/159] parisc: Use double word condition in 64bit CAS operation

From: Greg Kroah-Hartman
Date: Sat Sep 26 2015 - 17:33:44 EST

4.1-stable review patch. If anyone has any objections, please let me know.


From: John David Anglin <dave.anglin@xxxxxxxx>

commit 1b59ddfcf1678de38a1f8ca9fb8ea5eebeff1843 upstream.

The attached change fixes the condition used in the "sub" instruction.
A double word comparison is needed. This fixes the 64-bit LWS CAS
operation on 64-bit kernels.

I can now enable 64-bit atomic support in GCC.

Signed-off-by: John David Anglin <dave.anglin>
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

arch/parisc/kernel/syscall.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -821,7 +821,7 @@ cas2_action:
/* 64bit CAS */
#ifdef CONFIG_64BIT
19: ldd,ma 0(%sr3,%r26), %r29
- sub,= %r29, %r25, %r0
+ sub,*= %r29, %r25, %r0
b,n cas2_end
20: std,ma %r24, 0(%sr3,%r26)
copy %r0, %r28

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