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

[Kamalesh Babulal]

* Balbir Singh <bsingharora at gmail.com> [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 <duwe at suse.de>
> Signed-off-by: Balbir Singh <bsingharora at gmail.com>

Tested-by: Kamalesh Babulal <kamalesh at linux.vnet.ibm.com>