From b3fe35261e329e15736bc95630fd865df9896c66 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Fri, 2 Aug 2019 20:56:41 +1000
Subject: [PATCH] powerpc/64s/exception: machine check improve labels and
comments
References: jsc#PM-1334 jsc#SLE-9246 jsc#SLE-9251
Patch-mainline: v5.4-rc1
Git-commit: b3fe35261e329e15736bc95630fd865df9896c66
Short forward and backward branches can be given number labels,
but larger significant divergences in code path a more readable
if they're given descriptive names.
Also adjusts a comment to account for guest delivery.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802105709.27696-17-npiggin@gmail.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/kernel/exceptions-64s.S | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 3a7f18021365..c2474c9c8d41 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1052,7 +1052,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
*/
lbz r11,HSTATE_IN_GUEST(r13)
cmpwi r11,0 /* Check if coming from guest */
- bne 9f /* continue if we are. */
+ bne mce_deliver /* continue if we are. */
#endif
/*
@@ -1060,7 +1060,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
* exception handler which will deliver the MC event to this kernel.
*/
andi. r11,r12,MSR_PR /* See if coming from user. */
- bne 9f /* continue in V mode if we are. */
+ bne mce_deliver /* continue in V mode if we are. */
/*
* At this point we are coming from kernel context.
@@ -1088,8 +1088,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
MACHINE_CHECK_HANDLER_WINDUP
RFI_TO_KERNEL
-9:
- /* Deliver the machine check to host kernel in V mode. */
+mce_deliver:
+ /*
+ * This is a host user or guest MCE. Restore all registers, then
+ * run the "late" handler. For host user, this will run the
+ * machine_check_exception handler in virtual mode like a normal
+ * interrupt handler. For guest, this will trigger the KVM test
+ * and branch to the KVM interrupt similarly to other interrupts.
+ */
BEGIN_FTR_SECTION
ld r10,ORIG_GPR3(r1)
mtspr SPRN_CFAR,r10
--
2.23.0