From: Vasily Gorbik <gor@linux.ibm.com>
Date: Fri, 27 Jan 2023 14:57:43 +0100
Subject: [PATCH] s390/mem_detect: rely on diag260() if
 sclp_early_get_memsize() fails
References: bsc#1012628
Patch-mainline: 6.2.3
Git-commit: eb33f9eb304a4c18beb5ba6362eaa5c4beaf40d8

[ Upstream commit eb33f9eb304a4c18beb5ba6362eaa5c4beaf40d8 ]

In case sclp_early_get_memsize() fails but diag260() succeeds make sure
some sane value is returned. This error scenario is highly unlikely,
but this change makes system able to boot in such case.

Suggested-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Stable-dep-of: 22476f47b6b7 ("s390/boot: fix mem_detect extended area allocation")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 arch/s390/boot/mem_detect.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/boot/mem_detect.c b/arch/s390/boot/mem_detect.c
index 0a5821ef..41792a3a 100644
--- a/arch/s390/boot/mem_detect.c
+++ b/arch/s390/boot/mem_detect.c
@@ -176,7 +176,7 @@ unsigned long detect_memory(void)
 
 	if (!diag260()) {
 		mem_detect.info_source = MEM_DETECT_DIAG260;
-		return max_physmem_end;
+		return max_physmem_end ?: get_mem_detect_end();
 	}
 
 	if (max_physmem_end) {
-- 
2.35.3