Commit 613775d6 authored Nov 26, 2020 by Philipp Rudo Committed by Heiko Carstens Dec 09, 2020

s390/kexec_file: fix diag308 subcode when loading crash kernel



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: ee337f54 ("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>

parent 14d4c4fa

arch/s390/purgatory/head.S

+5 −4

Original line number	Diff line number	Diff line
		@@ -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: