powerpc: No need to preserve count register across system call

The count register is volatile so we don't need to preserve it.
Store zero to the entry in the exception frame.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 7f1e6de9a5a9e6d68188d7b14ff877278dc45cb5..ba72ddbe52389d846320a2cf19db78894a82a2da 100644 (file)
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -83,6 +83,7 @@ system_call_common:
        std     r11,GPR11(r1)
        std     r11,GPR12(r1)
        std     r11,_XER(r1)
+       std     r11,_CTR(r1)
        std     r9,GPR13(r1)
        mfcr    r9
        mflr    r10
@@ -90,8 +91,6 @@ system_call_common:
        std     r9,_CCR(r1)
        std     r10,_LINK(r1)
        std     r11,_TRAP(r1)
-       mfctr   r10
-       std     r10,_CTR(r1)
        std     r3,ORIG_GPR3(r1)
        ld      r2,PACATOC(r13)
        addi    r9,r1,STACK_FRAME_OVERHEAD