From daa3b3a991fbe47544cb565a4d396b3e22d637e9 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 commit d6df52e9996dcc2062c3d9c9123288468bb95b52 upstream. 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: Greg Kroah-Hartman --- arch/s390/mm/maccess.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c index 7be06475809b8..a40739ea3805e 100644 --- a/arch/s390/mm/maccess.c +++ b/arch/s390/mm/maccess.c @@ -58,13 +58,19 @@ static notrace long s390_kernel_write_odd(void *dst, const void *src, size_t siz */ void notrace s390_kernel_write(void *dst, const void *src, size_t size) { + unsigned long flags; long copied; - while (size) { - copied = s390_kernel_write_odd(dst, src, size); - dst += copied; - src += copied; - size -= copied; + flags = arch_local_save_flags(); + if (!(flags & PSW_MASK_DAT)) { + memcpy(dst, src, size); + } else { + while (size) { + copied = s390_kernel_write_odd(dst, src, size); + dst += copied; + src += copied; + size -= copied; + } } } -- 2.47.3