Re: [PATCH linux-next v3 05/14] crash: clean up kdump related config items
- To: Baoquan He <bhe@redhat.com>
- Cc: linux-kernel@vger.kernel.org, Dave Vasilevsky <dave@vasilevsky.ca>, Michael Ellerman <mpe@ellerman.id.au>, kexec@lists.infradead.org, debian-powerpc@lists.debian.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, loongarch@lists.linux.dev, akpm@linux-foundation.org, ebiederm@xmission.com, hbathini@linux.ibm.com, piliu@redhat.com, viro@zeniv.linux.org.uk, Sam James <sam@gentoo.org>
- Subject: Re: [PATCH linux-next v3 05/14] crash: clean up kdump related config items
- From: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
- Date: Thu, 22 Aug 2024 11:37:09 +0200
- Message-id: <[🔎] c5e9996e4d2ba2a0849d65f68e3dce94fffc5828.camel@physik.fu-berlin.de>
- In-reply-to: <ZscCMLfNbj2MDiaB@MiWiFi-R3L-srv>
- References: <20240124051254.67105-1-bhe@redhat.com> <20240124051254.67105-6-bhe@redhat.com> <[🔎] a9d9ecd1ed8d62eae47ec26257093495e6cbd44a.camel@physik.fu-berlin.de> <ZscCMLfNbj2MDiaB@MiWiFi-R3L-srv>
Hi Baoquan,
On Thu, 2024-08-22 at 17:17 +0800, Baoquan He wrote:
> > 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"
I think the architecture does support crash dumps, but I think the kernel has to
be booted from kexec in this case. Booting a kernel with CRASH_DUMP enabled won't
work from Open Firmware. So, I think CRASH_DUMP should just be disabled for
PPC_BOOK3S_32 by default and users who want to use it on these systems, will have to
enable it explicitly.
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer
`. `' Physicist
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
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