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Commit 1a708575 authored by Vasily Gorbik's avatar Vasily Gorbik Committed by Greg Kroah-Hartman
Browse files

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: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 627d15ee

arch/s390/mm/maccess.c

+9 −5
Original line number Diff line number Diff line
@@ -62,12 +62,16 @@ notrace void *s390_kernel_write(void *dst, const void *src, size_t size) 
	long copied;



	spin_lock_irqsave(&s390_kernel_write_lock, flags);

	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);



	return dst;