From: Vasily Gorbik <gor@linux.ibm.com>
Date: Wed, 24 Jun 2020 15:39:14 +0000 (+0200)
Subject: s390/maccess: add no DAT mode to kernel_write
X-Git-Tag: v5.15~3434^2~4
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d6df52e9996dcc2062c3d9c9123288468bb95b52;p=platform%2Fkernel%2Flinux-starfive.git

s390/maccess: add no DAT mode to kernel_write

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>
---

diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 22a0be6..1d17413 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);