On 08/22/24 at 09:33am, John Paul Adrian Glaubitz wrote:

Hi Baoquan,

On Wed, 2024-01-24 at 13:12 +0800, Baoquan He wrote:

quoted

By splitting CRASH_RESERVE and VMCORE_INFO out from CRASH_CORE, cleaning
up the dependency of FA_DMUMP on CRASH_DUMP, and moving crash codes from
kexec_core.c to crash_core.c, now we can rearrange CRASH_DUMP to
depend on KEXEC_CORE, and make CRASH_DUMP select CRASH_RESERVE and
VMCORE_INFO.

KEXEC_CORE won't select CRASH_RESERVE and VMCORE_INFO any more because
KEXEC_CORE enables codes which allocate control pages, copy
kexec/kdump segments, and prepare for switching. These codes are shared
by both kexec reboot and crash dumping.

Doing this makes codes and the corresponding config items more
logical (the right item depends on or is selected by the left item).

PROC_KCORE -----------> VMCORE_INFO

           |----------> VMCORE_INFO
FA_DUMP----|
           |----------> CRASH_RESERVE

                                                ---->VMCORE_INFO
                                               /
                                               |---->CRASH_RESERVE
KEXEC      --|                                /|
             |--> KEXEC_CORE--> CRASH_DUMP-->/-|---->PROC_VMCORE
KEXEC_FILE --|                               \ |
                                               \---->CRASH_HOTPLUG

KEXEC      --|
             |--> KEXEC_CORE--> kexec reboot
KEXEC_FILE --|

Signed-off-by: Baoquan He <redacted>
---
 kernel/Kconfig.kexec | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
index 8faf27043432..6c34e63c88ff 100644
--- a/kernel/Kconfig.kexec
+++ b/kernel/Kconfig.kexec

@@ -9,8 +9,6 @@ config VMCORE_INFO
 	bool
 
 config KEXEC_CORE
-	select VMCORE_INFO
-	select CRASH_RESERVE
 	bool
 
 config KEXEC_ELF

@@ -99,8 +97,11 @@ config KEXEC_JUMP
 
 config CRASH_DUMP
 	bool "kernel crash dumps"
+	default y
 	depends on ARCH_SUPPORTS_CRASH_DUMP
-	select KEXEC_CORE
+	depends on KEXEC_CORE
+	select VMCORE_INFO
+	select CRASH_RESERVE
 	help
 	  Generate crash dump after being started by kexec.
 	  This should be normally only set in special crash dump kernels

The change to enable CONFIG_CRASH_DUMP by default apparently broke the boot
on 32-bit Power Macintosh systems which fail after GRUB with:

	"Error: You can't boot a kdump kernel from OF!"

We may have to turn this off for 32-bit Power Macintosh systems.

See this thread on debian-powerpc ML: https://lists.debian.org/debian-powerpc/2024/07/msg00001.html

If so, fix need be made.

We may need change in ARCH_SUPPORTS_CRASH_DUMP of ppc, can you or anyone
post a patch? I don't know how to identify 32-bit Power Macintosh.

arch/powerpc/Kconfig:
===
config ARCH_SUPPORTS_CRASH_DUMP
        def_bool PPC64 || PPC_BOOK3S_32 || PPC_85xx || (44x && !SMP)
        
config ARCH_SELECTS_CRASH_DUMP
        def_bool y
        depends on CRASH_DUMP
        select RELOCATABLE if PPC64 || 44x || PPC_85xx
......
config PHYSICAL_START
        hex "Physical address where the kernel is loaded" if PHYSICAL_START_BOOL
        default "0x02000000" if PPC_BOOK3S && CRASH_DUMP && !NONSTATIC_KERNEL
        default "0x00000000"