[PATCH 4.17 050/220] powerpc/powernv: copy/paste - Mask SO bit in CR

[Greg Kroah-Hartman]

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

------------------

From: Haren Myneni <haren@xxxxxxxxxx>

commit 75743649064ec0cf5ddd69f240ef23af66dde16e upstream.

NX can set the 3rd bit in CR register for XER[SO] (Summary overflow)
which is not related to paste request. The current paste function
returns failure for a successful request when this bit is set. So mask
this bit and check the proper return status.

Fixes: 2392c8c8c045 ("powerpc/powernv/vas: Define copy/paste interfaces")
Cc: stable@xxxxxxxxxxxxxxx # v4.14+
Signed-off-by: Haren Myneni <haren@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/powerpc/platforms/powernv/copy-paste.h |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/powerpc/platforms/powernv/copy-paste.h
+++ b/arch/powerpc/platforms/powernv/copy-paste.h
@@ -42,5 +42,6 @@ static inline int vas_paste(void *paste_
 		: "b" (offset), "b" (paste_address)
 		: "memory", "cr0");
 
-	return (cr >> CR0_SHIFT) & CR0_MASK;
+	/* We mask with 0xE to ignore SO */
+	return (cr >> CR0_SHIFT) & 0xE;
 }