Re: [RFC][PATCH][v2] Enable livepatching for powerpc

* Balbir Singh [off-list ref] [2016-03-03 18:00:54]:

Changelog:
	1. Implement review comments by Michael
	2. The previous version compared _NIP from the
	   wrong location to check for whether we
	   are going to a patched location

This applies on top of the patches posted by Michael 
https://patchwork.ozlabs.org/patch/589791/

It enables livepatching. This takes patch 6/8 and 7/8 of v8 as the base.
Removes the extra strict check in gcc-profile-kernel-notrace.sh
and adds logic for checking offsets in livepatch. The patch
for HAVE_C_RECORDMCOUNT is not required and not used here.

Depending on whether or not a TOC is generated, the offset
for _mcount can be +16,+12,+8,+4. The changes are such that the
offset checks are specific to powerpc.

TODOs
1. Build a version with offsets removed and rebuild
   ftrace_location() sort of functionality
2. Make livepatching experimental on powerpc

Comments? Testing? I tested the sample in the livepatch
directory

References

1. https://patchwork.ozlabs.org/patch/581521/
2. https://patchwork.ozlabs.org/patch/587464/

Signed-off-by: Torsten Duwe <redacted>
Signed-off-by: Balbir Singh <bsingharora@gmail.com>

Tested-by: Kamalesh Babulal <redacted>