From 3038bbd1bb33a8cbb1e9f21d6bb7aa82bf1a2111 Mon Sep 17 00:00:00 2001 From: Philipp Rudo Date: Thu, 26 Nov 2020 18:31:08 +0100 Subject: [PATCH] s390/kexec_file: fix diag308 subcode when loading crash kernel commit 613775d62ec60202f98d2c5f520e6e9ba6dd4ac4 upstream. diag308 subcode 0 performes a clear reset which inlcudes the reset of all registers in the system. While this is the preferred behavior when loading a normal kernel via kexec it prevents the crash kernel to store the register values in the dump. To prevent this use subcode 1 when loading a crash kernel instead. Fixes: ee337f5469fd ("s390/kexec_file: Add crash support to image loader") Cc: # 4.17 Signed-off-by: Philipp Rudo Reported-by: Xiaoying Yan Tested-by: Lianbo Jiang Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman --- arch/s390/purgatory/head.S | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/s390/purgatory/head.S b/arch/s390/purgatory/head.S index 5a10ce34b95d..3d1c31e0cf3d 100644 --- a/arch/s390/purgatory/head.S +++ b/arch/s390/purgatory/head.S @@ -62,14 +62,15 @@ jh 10b .endm -.macro START_NEXT_KERNEL base +.macro START_NEXT_KERNEL base subcode lg %r4,kernel_entry-\base(%r13) lg %r5,load_psw_mask-\base(%r13) ogr %r4,%r5 stg %r4,0(%r0) xgr %r0,%r0 - diag %r0,%r0,0x308 + lghi %r1,\subcode + diag %r0,%r1,0x308 .endm .text @@ -123,7 +124,7 @@ ENTRY(purgatory_start) je .start_crash_kernel /* start normal kernel */ - START_NEXT_KERNEL .base_crash + START_NEXT_KERNEL .base_crash 0 .return_old_kernel: lmg %r6,%r15,gprregs-.base_crash(%r13) @@ -227,7 +228,7 @@ ENTRY(purgatory_start) MEMCPY %r9,%r10,%r11 /* start crash kernel */ - START_NEXT_KERNEL .base_dst + START_NEXT_KERNEL .base_dst 1 load_psw_mask: