Re: [PATCH] [makedumpfile] Implement memory regions on IA64

["Ken'ichi Ohmichi" <oomichi@mxs.nes.nec.co.jp>]

Hi Bernhard,

2007/05/16 00:08:45 +0200, Bernhard Walle <bwalle@suse.de> wrote:
>Hello,
>
>* Bernhard Walle <bwalle@suse.de> [2007-05-14 23:49]:
>> 
>> I'm working on support for the 4 layer pagetable.
>
>Here's my first attempt. It works with SLES 10, SP1 on a Tiger4
>machine with 16 GiB of memory. (I had still problems with a big
>SGI machine when creating the bitmap. I'm investigating this, too.)
>
>The problem is not to implement the 4 layer page table, but to
>*detect* it. crash uses the built-in configuration data in the kernel
>image, and that's what I used in my patch. If you have a better and
>still reliable method, I'm open to suggestions. :-)

Thank you for the patch.
I tested makedumpfile with your patch on linux-2.6.18 ia64,
and it output the following message and failed.

Error message:
  $ makedumpfile -cd 31 -x vmlinux vmcore dumpfile
  Can't read kernel cofiguration from kernel binary
  makedumpfile Failed.
  $

The reason was that kernel binary file didn't have "kernel_config_data" 
because CONFIG_IKCONFIG was not set in my .config.
It is uncertain that "kernel_config_data" exists in a kernel binary.

I propose that makedumpfile distinguishes the page table (3L or 4L)
by checking the defined file name of pud_t.
I'm trying for the above implementation.
I will send you the patch when it is complete.

All the pud_t(s) of linux-2.6.16 - 2.6.21 are defined in the following files:

CONFIG_PGTABLE_4
  include/asm-ia64/page.h

!CONFIG_PGTABLE_4
  include/asm-generic/pgtable-nopud.h


Thanks
Ken'ichi Ohmichi

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