The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 26521412ae22d06caab98721757b2721c6d7c46c Mon Sep 17 00:00:00 2001
From: Sven Schnelle <svens@xxxxxxxxxxxxx>
Date: Wed, 3 Feb 2021 09:16:45 +0100
Subject: [PATCH] s390: fix kernel asce loading when sie is interrupted
If a machine check is coming in during sie, the PU saves the
control registers to the machine check save area. Afterwards
mcck_int_handler is called, which loads __LC_KERNEL_ASCE into
%cr1. Later the code restores %cr1 from the machine check area,
but that is wrong when SIE was interrupted because the machine
check area still contains the gmap asce. Instead it should return
with either __KERNEL_ASCE in %cr1 when interrupted in SIE or
the previous %cr1 content saved in the machine check save area.
Fixes: 87d598634521 ("s390/mm: remove set_fs / rework address space handling")
Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx> # v5.8+
Reviewed-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index f7953bb17558..377294969954 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -558,6 +558,7 @@ ENTRY(mcck_int_handler)
lg %r15,__LC_MCCK_STACK
.Lmcck_skip:
la %r11,STACK_FRAME_OVERHEAD(%r15)
+ stctg %c1,%c1,__PT_CR1(%r11)
lctlg %c1,%c1,__LC_KERNEL_ASCE
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
lghi %r14,__LC_GPREGS_SAVE_AREA+64
@@ -573,8 +574,6 @@ ENTRY(mcck_int_handler)
xgr %r10,%r10
mvc __PT_R8(64,%r11),0(%r14)
stmg %r8,%r9,__PT_PSW(%r11)
- la %r14,4095
- mvc __PT_CR1(8,%r11),__LC_CREGS_SAVE_AREA-4095+8(%r14)
xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
lgr %r2,%r11 # pass pointer to pt_regs
