This is a note to let you know that I've just added the patch titled
s390/maccess: add no DAT mode to kernel_write
to the 5.7-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:
s390-maccess-add-no-dat-mode-to-kernel_write.patch
and it can be found in the queue-5.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9644120dd9b51ce82b384dcf2236c2a2324fddee
Author: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Date: Wed Jun 24 17:39:14 2020 +0200
s390/maccess: add no DAT mode to kernel_write
[ Upstream commit d6df52e9996dcc2062c3d9c9123288468bb95b52 ]
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@xxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 22a0be655f27a..1d17413b319a4 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -62,11 +62,15 @@ notrace void *s390_kernel_write(void *dst, const void *src, size_t size)
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);
