[PATCHv3 0/9] Support Xen versions up to xen-4.1

[Stefan Bader]

On 12.09.2012 16:39, Trapp, Norbert wrote:
> Hello Atsushi, Petr, Stefan et al.,
> 

Hi Norbert,

> When applying the makedumpfile Xen4 patches to the makedumpfile 1.5.0
> version and using it for a crash file to save just the dom0 and xen pages
> it again worked splendid in that makedumpfile was much faster than without
> the Xen4 patches. Alas I had to remove the OFFSET_IN_UNION_INIT(page._domain,
> "page_info", "domain") call because OFFSET_IN_UNION_INIT was no longer present.
> It didn't matter much because the call is only needed for makedumpfile -g or when
> using the /boot/xen-syms file. In the current 1.5.0  makedumpfile.c version you
> see
> 
>     OFFSET_INIT(page_info._domain, "page_info", "u").
> 
> The Xen4 patch modified this because the _domain structure member is in different
> unions for different version (x86, ia64) and may also not be the first entry in
> the union depending on the Xen version.
> 
>     OFFSET_IN_UNION_INIT(page_info._domain, "page_info", "_domain");
> 
> As an experiment I tried to use
> 

>     OFFSET_INIT(page_info._domain, "page_info", "domain")

Just to make sure and since I am a bit lazy: with the Xen patch the page_info
structure has a member (somewhere) named domain? (or _domain)?

> 
> with makedumpfile 1.5.0. To get the correct offset I had to
> modify the dwarf_info.c code:
> 
> --- ../makedumpfile-1.5.0/dwarf_info.c  2012-09-06 07:30:23.000000000 +0200
> +++ dwarf_info.c        2012-09-12 15:49:23.000000000 +0200
> @@ -449,8 +449,8 @@
>  static int
>  is_anonymous_container(Dwarf_Die *die)
>  {
> -       if (dwarf_diename(die))
> -               return FALSE;
> +       //if (dwarf_diename(die))
> +       //      return FALSE;
>         if (dwarf_tag(die) == DW_TAG_structure_type)
>                 return TRUE;
>         if (dwarf_info.cmd != DWARF_INFO_GET_MEMBER_OFFSET_1ST_UNION
> @@ -495,7 +495,7 @@
>                  * Descend into anonymous members and search for member
>                  * there.
>                  */
> -               if (!name) {
> +               if ((!name) || (strcmp(name, dwarf_info.member_name) != 0)) {
>                         if (!get_die_type(walker, &die_type))
>                                 continue;
>                         if (is_anonymous_container(&die_type))
> 
> 
> This is not a patch but just a description of what I modified for a test.
> The underlying question is why only the anonymous unions are used and not the
> ones with a name.

I made the patch because one element in some anonymous structure/union combo was
not found in newer kernels and the previous exceptions for such a thing were
hard coded. But as far as the dwarf info I was looking at the named
structures/unions were handled and I did not want to modify that case without a
way to test.

-Stefan
> 
> With kind regards
> 
> 	Norbert
> 
> Norbert Trapp
> PDG ES&S SWE OS 6
> 
> FUJITSU
> Fujitsu Technology Solutions GmbH
> Domagkstraße 28, D-80807 München, Germany
> E-mail: Norbert.Trapp at ts.fujitsu.com
> Web: ts.fujitsu.com
> Company details: ts.fujitsu.com/imprint
> 
>> -----Original Message-----
>> From: Atsushi Kumagai [mailto:kumagai-atsushi at mxc.nes.nec.co.jp]
>> Sent: Monday, September 03, 2012 7:01 AM
>> To: Trapp, Norbert; petr at tesarici.cz
>> Cc: kexec at lists.infradead.org
>> Subject: Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1
>>
> ...
>>
>> Thank you for your report, that's good.
>> So, I'll review these patches for makedumpfile-1.5.1.
>>
>>
>> Thanks
>> Atsushi Kumagai
> 


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