From: Vasily Gorbik <gor@linux.ibm.com>
Date: Wed, 24 Jun 2020 17:39:14 +0200
Subject: s390/maccess: add no DAT mode to kernel_write
Patch-mainline: v5.8-rc5
Git-commit: d6df52e9996dcc2062c3d9c9123288468bb95b52
References: bsc#1176449
To be able to patch kernel code before paging is initialized do plain
memcpy if DAT is off. This is required to enable early jump label
initialization.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Nicolai Stange <nstange@suse.de>
---
arch/s390/mm/maccess.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -62,11 +62,15 @@ notrace void *s390_kernel_write(void *ds
long copied;
spin_lock_irqsave(&s390_kernel_write_lock, flags);
- while (size) {
- copied = s390_kernel_write_odd(tmp, src, size);
- tmp += copied;
- src += copied;
- size -= copied;
+ if (!(flags & PSW_MASK_DAT)) {
+ memcpy(dst, src, size);
+ } else {
+ while (size) {
+ copied = s390_kernel_write_odd(tmp, src, size);
+ tmp += copied;
+ src += copied;
+ size -= copied;
+ }
}
spin_unlock_irqrestore(&s390_kernel_write_lock, flags);