Roland McGrath wrote:
Ananth forwarded me this mail as it has some mention of kexec.
In this posting you mentioned that the recent regset changes
you are planning might break kexec.
Could you elaborate on this ? Also will these changes break
kexec only on powerpc or other arch also ?
Please see http://lkml.org/lkml/2008/1/18/583
No arch's kexec is affected unless it has removed its ELF_CORE_COPY_REGS
macro. My x86 changes in the x86/mm tree did that, but it's now been added
back to unbreak kexec. The powerpc patches I posted also remove the macro,
but those patches haven't been incorporated anywhere yet anyway; it's
simple just not to remove the macro (it's part of patch 10/16 in the
powerpc patch series; patch 10 does nothing but remove old code, all of
which but this is truly unused).
...
As I mentioned in that lkml message, I think it would be better for kexec
to clean up its arch interfaces not to use elf_core_copy_regs at all.
There is already machine-specific kexec code that goes through contortions
with register values, so it might as well be consolidated into a single set
of contortions that produces the final data format (i.e. elf_gregset_t).
But there is no big rush to resolve that. The machine-specific macro
ELF_CORE_COPY_REGS no longer has any use for core files and it's unsightly
to keep it around with that name, but that's all.
Thanks for the descriptive mail.
kexec will not be broken by the user_regset changes when they are merged.
If kexec cleaned up, that and user_regset support together would permit
each arch to drop the ELF_CORE_COPY_REGS macro and cut down the clutter.
Will try to make necessary modifications for this.
Thanks
-Sachin
