[PATCH linux-next v3 05/14] crash: clean up kdump related config items

[Baoquan He]

On 08/22/24 at 11:37am, John Paul Adrian Glaubitz wrote:
> 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.

If so, below patch possiblly can fix it. Can you help check if it's OK?