From 1a70857590f70efbfb67e088220e639c2766d63f Mon Sep 17 00:00:00 2001 From: Vasily Gorbik Date: Wed, 24 Jun 2020 17:39:14 +0200 Subject: [PATCH] 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 Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- arch/s390/mm/maccess.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c index 22a0be655f27..1d17413b319a 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);