This is a note to let you know that I've just added the patch titled
powerpc/64s: Fix i-side SLB miss bad address handler saving nonvolatile GPRs
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-64s-fix-i-side-slb-miss-bad-address-handler-saving-nonvolatile-gprs.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 52396500f97c53860164debc7d4f759077853423 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@xxxxxxxxx>
Date: Fri, 23 Mar 2018 15:53:38 +1000
Subject: powerpc/64s: Fix i-side SLB miss bad address handler saving nonvolatile GPRs
From: Nicholas Piggin <npiggin@xxxxxxxxx>
commit 52396500f97c53860164debc7d4f759077853423 upstream.
The SLB bad address handler's trap number fixup does not preserve the
low bit that indicates nonvolatile GPRs have not been saved. This
leads save_nvgprs to skip saving them, and subsequent functions and
return from interrupt will think they are saved.
This causes kernel branch-to-garbage debugging to not have correct
registers, can also cause userspace to have its registers clobbered
after a segfault.
Fixes: f0f558b131db ("powerpc/mm: Preserve CFAR value on SLB miss caused by access to bogus address")
Cc: stable@xxxxxxxxxxxxxxx # v4.9+
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/exceptions-64s.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -723,7 +723,7 @@ EXC_COMMON_BEGIN(bad_addr_slb)
ld r3, PACA_EXSLB+EX_DAR(r13)
std r3, _DAR(r1)
beq cr6, 2f
- li r10, 0x480 /* fix trap number for I-SLB miss */
+ li r10, 0x481 /* fix trap number for I-SLB miss */
std r10, _TRAP(r1)
2: bl save_nvgprs
addi r3, r1, STACK_FRAME_OVERHEAD
Patches currently in stable-queue which might be from npiggin@xxxxxxxxx are
queue-4.9/powerpc-64s-fix-lost-pending-interrupt-due-to-race-causing-lost-update-to-irq_happened.patch
queue-4.9/powerpc-64s-fix-i-side-slb-miss-bad-address-handler-saving-nonvolatile-gprs.patch