Re: [PATCH v3 07/12] ppc64/kexec_file: add support to relocate purgatory

[Thiago Jung Bauermann]

Hari Bathini <hbathini@xxxxxxxxxxxxx> writes:

> On 16/07/20 5:50 am, Thiago Jung Bauermann wrote:
>> 
>> Hari Bathini <hbathini@xxxxxxxxxxxxx> writes:
>> 
>>> So, add support to relocate purgatory in kexec_file_load system call
>>> by setting up TOC pointer and applying RELA relocations as needed.
>> 
>> If we do want to use a C purgatory, Michael Ellerman had suggested
>> building it as a Position Independent Executable, which greatly reduces
>> the number and types of relocations that are needed. See patches 4 and 9
>> here:
>> 
>> https://lore.kernel.org/linuxppc-dev/1478748449-3894-1-git-send-email-bauerman@xxxxxxxxxxxxxxxxxx/
>> 
>> In the series above I hadn't converted x86 to PIE. If I had done that,
>> possibly Dave Young's opinion would have been different. :-)
>> 
>> If that's still not desirable, he suggested in that discussion lifting
>> some code from x86 to generic code, which I implemented and would
>> simplify this patch as well:
>> 
>> https://lore.kernel.org/linuxppc-dev/5009580.5GxAkTrMYA@morokweng/
>> 
>
> Agreed. But I prefer to work on PIE and/or moving common relocation_add code
> for x86 & s390 to generic code later when I try to build on these purgatory
> changes. So, a separate series later to rework purgatory with the things you
> mentioned above sounds ok?

Sounds ok to me. Let's see what the maintainers think, then.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center