Re: [RESEND PATCH 1/4] ppc64 FTRACE_WITH_REGS implementation

From: Steven Rostedt
Date: Fri Jun 19 2015 - 09:25:56 EST


On Thu, 18 Jun 2015 18:21:07 +0200
Torsten Duwe <duwe@xxxxxx> 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 <duwe@xxxxxxx>
> --

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 <duwe@xxxxxxx>
--
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 <rostedt@xxxxxxxxxxx>

-- Steve


> 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(-)
> --
> diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
> index e366187..6111191 100644
> --- a/arch/powerpc/include/asm/ftrace.h
> +++ b/arch/powerpc/include/asm/ftrace.h
--
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