Re: [RFC PATCH 1/4] objtool: Add --mnop as an option to --mcount

[Naveen N. Rao]

Peter Zijlstra wrote:
> On Tue, May 24, 2022 at 04:01:48PM +0530, Naveen N. Rao wrote:
>
> > We need to know for sure either way. Nop'ing out the _mcount locations at
> > boot allows us to discover existing long branch trampolines. If we want to
> > avoid it, we need to note down those locations during build time.
> >
> > Do you have a different approach in mind?
>
> If you put _mcount in a separate section then the compiler cannot tell
> where it is and is forced to always emit a long branch trampoline.
>
> Does that help?

That's an interesting thought. Depending on the type of trampoline the 
compiler emits, I might be able to use this approach. We will still need 
objtool on powerpc  so that we can note down those trampoline locations.


Thanks,
Naveen