Subject: Re: sparse, kernel-only crashdumps
To: None <tech-kern@NetBSD.org>
From: David Young <firstname.lastname@example.org>
Date: 10/07/2004 16:17:55
On Thu, Oct 07, 2004 at 01:39:11AM -0500, David Young wrote:
> It looks to me like it isn't too hard to make a sparse crashdump on x86
> that contains only the pages that are mapped into kernel virtual memory,
> the page directory and page table pages (PDP and PTPs). Does a crashdump
> require any other pages? I have a need for compact crashdumps, so I am
> going to work on this over the weekend.
Ok, just to clarify: I was not asking for new requirements. I will see
what I can do to split i386 into generic MI/MD portions, but I have no
intention of writing generic crash dump support. Cross-debugging is
totally out of the scope of this weekend project. I have no interest
whatsoever in extending or fixing kcore/libkvm. FWIW, I think the kcore
format is adequate to support i386 kernel-only dumps already.
I may have underestimated the amount of work this will take. Just for
instance, I don't know how/where to find the kernel's .data or .bss
sections---I'd assumed they were in kernel virtual memory. If you
have any pointers, it might save me a couple hours hunting through the
I intend to commit whatever I come up with, when it works, as an option
enabled by 'options X86_KERNEL_ONLY_DUMP'.
David Young OJC Technologies
email@example.com Urbana, IL * (217) 278-3933