Re: [PATCH v2 1/2] arm64: implement FTRACE_WITH_REGS

[Steven Rostedt]

On Fri, 8 Jul 2016 10:48:24 -0500
Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:


> My understanding is that other arches don't need this check because they
> use -mfentry, so they have to modify the "call fentry" instruction to a
> nop on startup.
> 
> Here, with -fprolog-pad, it's already a nop, so no change is needed.
> 

That's what I was thinking. But as I stated in another email (probably
in the air when you wrote this), the call to ftrace_modify_code() may be
completely circumvented by ftrace_make_nop() if the addr is MCOUNT_ADDR.

-- Steve