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s390/kexec_file: fix diag308 subcode when loading crash kernel

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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: ee337f5469 ("s390/kexec_file: Add crash support to image loader")
Cc: <stable@vger.kernel.org> # 4.17
Signed-off-by: Philipp Rudo <prudo@linux.ibm.com>
Reported-by: Xiaoying Yan <yiyan@redhat.com>
Tested-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Philipp Rudo 2020-11-26 18:31:08 +01:00 committed by Greg Kroah-Hartman
parent 0063e1142a
commit bc8f8833e9
1 changed files with 5 additions and 4 deletions
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9
arch/s390/purgatory/head.S
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@ -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: