[lkml]   [2007]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [Fastboot] [PATCH 1/1] Allow i386 crash kernels to handle x86_64 dumps
On 3/16/07, Ian Campbell <> wrote:
> On Fri, 2007-03-16 at 11:40 +0900, Magnus Damm wrote:
> > Right. And maybe it's a good idea to make sure that this feature is
> > actually supported by kexec-tools before adding code to the kernel?
> I sent patches to the fastboot list at the same time I sent these ones
> to support differences in the underlying hypervisor architecture in the
> tools.

Oh, that's good news. I have not seen them yet...

> They haven't appeared in the archives yet so I fear they have gone
> astray. I'll resend when I get to the office in a bit.

... so please resend.

We've just frozen the kexec-tools-testing tree for an upcoming
release, but if you resend soon and your patches are trivial you may
be able to talk us into merging your changes before the release..

> The tools already have support for introducing a SHIM when kexecing
> between different architectures (at least in the 64->32 direction if I
> understand kexec-tools-testing/purgatory/arch/i386/compat_x86_64.S and
> k-t-t.../kexec/arch/i386/compat_x86_64.S correctly). This is really just
> an extension of that.

Right, the mode switching code in purgatory.

> > My gut feeling about this is that you are begging for trouble. The
> > kexec/kdump solution is fragile just by itself, and trying to go
> > between architectures is just going to be painful.
> It works fine under Xen and I think going from 64Xen+32Kernel->32Kernel
> makes more sense than going from 64Xen+32Kernel->64Kernel. As I said
> originally I'm not so convinced it makes sense in the native case but I
> see no reason to outlaw it (people get to keep both pieces etc...)

For kexec I think it is just fine. But for kdump, are you sure things
will work out ok? There are some differences between the i386 and
x86_64 kexec-tools code and I wonder if feeding i386 info into an
x86_64 kernel will work properly.


/ magnus
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-03-16 09:03    [W:0.069 / U:11.056 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site