From: Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>
To: linuxppc-dev <linuxppc-dev@ozlabs.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: KVM <kvm@vger.kernel.org>, KVM-PPC <kvm-ppc@vger.kernel.org>
Subject: [PATCH v2 1/2] Powernv: Remove the usage of PACAR1 from opal wrappers
Date: Sun, 15 May 2016 09:44:13 +0530 [thread overview]
Message-ID: <20160515041413.2280.747.stgit@mars> (raw)
From: Mahesh Salgaonkar <mahesh@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@linux.vnet.ibm.com>
Acked-by: Michael Ellerman <mpe@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
next reply other threads:[~2016-05-15 4:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-15 4:14 Mahesh J Salgaonkar [this message]
2016-05-15 4:14 ` [PATCH v2 2/2] powerpc/book3s: Fix TB corruption in guest exit path on HMI interrupt Mahesh J Salgaonkar
2016-05-15 4:25 ` Mahesh J Salgaonkar
2017-12-19 14:35 ` Alexander Graf
2016-06-24 9:21 ` [PATCH v2 1/2] Powernv: Remove the usage of PACAR1 from opal wrappers Paul Mackerras
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