[PATCH v2 1/2] Powernv: Remove the usage of PACAR1 from opal wrappers

Mahesh J Salgaonkar mahesh at linux.vnet.ibm.com
Sun May 15 14:14:13 AEST 2016

From: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>

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 at linux.vnet.ibm.com>
Acked-by: Michael Ellerman <mpe at ellerman.id.au>
 arch/powerpc/platforms/powernv/opal-wrappers.S |    2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index e45b88a..df6ad94 100644
--- 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

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