On Thu, 18 Jun 2015 18:21:07 +0200
Torsten Duwe [off-list ref] wrote:

Implement FTRACE_WITH_REGS for powerpc64, on ELF ABI v2.
Initial work started by Vojtech Pavlik, used with permission.

  * arch/powerpc/kernel/entry_64.S:
    - enhance _mcount with a stub to test (ftrace_trace_function == &ftrace_stub)
      as suggested in Documentation/trace/ftrace-design.txt
      (for reference only, patched out at runtime)
    - Implement an effective ftrace_caller that works from within the kernel
      binary as well as from modules.
  * arch/powerpc/kernel/ftrace.c:
    - be prepared to deal with ppc64 ELV ABI v2, especially calls to _mcount
      that result from gcc -mprofile-kernel
  * arch/powerpc/kernel/module_64.c:
    - do not save the TOC pointer on the trampoline when the destination
      is ftrace_caller. This trampoline jump happens from a function prologue
      before a new stack frame is set up, so bad things may happen otherwise...
    - relax is_module_trampoline() to recognise the modified trampoline.

Signed-off-by: Torsten Duwe <redacted>
--

FYI, the standard notation after the change log is '---' not '--'. That
way git will chop off this from the change log. When I did a git am -s
on this patch I had:

    Signed-off-by: Torsten Duwe [off-list ref]
    --
     arch/powerpc/include/asm/ftrace.h |    5 +
     arch/powerpc/kernel/entry_64.S    |  112 +++++++++++++++++++++++++++++++-------
     arch/powerpc/kernel/ftrace.c      |   67 ++++++++++++++++++++--
     arch/powerpc/kernel/module_64.c   |   33 ++++++++++-
     4 files changed, 186 insertions(+), 31 deletions(-)
    --
    Signed-off-by: Steven Rostedt [off-list ref]

-- Steve