Re: [PATCH 1/2] ppc64le live patch: clear out storage location(s) in mini stack frame

On 10/03/16 04:28, Torsten Duwe wrote:

This can be applied on top of Petr Mladek's v4 rework of the ppc64le
live patching. Inspired by Balbir Singh's v5, information about the
callee's r2 is stored in a "reserved" 32 bit location in the caller's
stack frame, instead of 64 bits in the newly created mini frame 24(r1).

It only needs to work for a local call, when caller's TOC == callee's
TOC, and along with the return address (LR) it's all within a 4GiB
range (+-31 bits). If the original call already was global, we are
allowed to restore any nonsense into r2, because the global caller
will restore its TOC anyway from the ABI compliant location 24(r1)
right after return.

Hi, Torsten

Sorry, I've had no time to test this. Caught up with something else for the moment.
Hopefully I'll get a chance over the weekend.

Have you tested this against Petr's sample changes to patch printk?

Balbir Singh.