[v7,0/3] arm64: ftrace with regs

Message

Torsten Duwe Jan. 18, 2019, 4:37 p.m. UTC

So here's v7 of ftrace with regs only. I've split out the CC_FLAGS_FTRACE
cleanup and the gcc activation into separate patches, respectively. The set
should include all of Mark's requested changes. Most notably, it now patches
in the first insn "mov x9, lr" right at startup, to avoid the races we
discussed; I'm conveniently abusing the initial _make_nop for that. The empty
mcount: routine caused a lot of Q's, so it's gone now.

I updated the accompanying livepatch patches here as well, in case somebody is
interested ;) They have only been updated to match this current ftrace-regs set,
not more.

The whole series applies cleanly on 5.0-rc2

in detail:

changes since v6:

* change the stack layout once more; I hope I have it the "standard" way now.
  And yes, it looks simpler and cleaner; thanks, Mark, for nagging.

* split out the independent Kconfig and Makefile changes

* fixed style issues

* s/fp/x29/g

* MCOUNT_ADDR is now merely a 64-bit magic, as this is totally sufficient.

* QUICK_LR_SAVE renamed back to MOV_X9_X30.

* place MOV_X9_X30 insns on bootup, and only flip b <-> nop at runtime

* graph tracer "ifdeffery" reshuffle

	Torsten