UBUNTU: SAUCE: Powernv: Remove the usage of PACAR1 from opal wrappers

BugLink: http://bugs.launchpad.net/bugs/1537881
https://lists.ozlabs.org/pipermail/linuxppc-dev/2016-January/138009.html

OPAL_CALL wrapper code sticks the r1 (stack pointer) into PACAR1 purely
for debugging purpose only. The power7_wakeup* functions relies on stack
pointer saved in PACAR1. Any opal call made using opal wrapper (directly
or in-directly) before we fall through power7_wakeup*, then it ends up
replacing r1 in PACAR1(r13) leading to kernel panic. So far we don't see
any issues because we have never made any opal calls using OPAL wrapper
before power7_wakeup*. But the subsequent HMI patch would need to invoke
C calls during cpu wakeup/idle path that in-directly makes opal call using
opal wrapper. This patch facilitates the subsequent HMI patch by removing
usage of PACAR1 from opal call wrapper.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index b7a464fef7a77be52671a5ef0679f62453cdbede..62fe496723c51659b5a3a22cdf387373bc61f76c 100644 (file)
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -64,7 +64,6 @@ END_FTR_SECTION(0, 1);                                                \
        OPAL_BRANCH(opal_tracepoint_entry) \
        mfcr    r12;                    \
        stw     r12,8(r1);              \
-       std     r1,PACAR1(r13);         \
        li      r11,0;                  \
        mfmsr   r12;                    \
        ori     r11,r11,MSR_EE;         \
@@ -127,7 +126,6 @@ opal_tracepoint_entry:
        mfcr    r12
        std     r11,16(r1)
        stw     r12,8(r1)
-       std     r1,PACAR1(r13)
        li      r11,0
        mfmsr   r12
        ori     r11,r11,MSR_EE