Hi Nick,
Nicholas Piggin wrote:
The new mprofile-kernel mcount sequence is
mflr r0
bl _mcount
Dynamic ftrace patches the branch instruction with a noop, but leaves
the mflr. mflr is executed by the branch unit that can only execute one
per cycle on POWER9 and shared with branches, so it would be nice to
avoid it where possible.
This patch is a hacky proof of concept to nop out the mflr. Can we do
this or are there races or other issues with it?
Thanks for implementing this. I don't see a problem with this.
- Naveen
