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

From: "Naveen N. Rao" <[email-masked]>
Date: Tue, 24 May 2022 15:45:20 +0530

Christophe Leroy wrote:
> 
> 
> Le 23/05/2022 à 19:55, Sathvika Vasireddy a écrit :
>> Architectures can select HAVE_NOP_MCOUNT if they choose
>> to nop out mcount call sites. If that config option is
>> selected, then --mnop is passed as an option to objtool,
>> along with --mcount.
>> 
> 
> Is there a reason not to nop out mcount call sites on powerpc as well ?

Yes, if there are functions that are out of range of _mcount(), then the 
linker would have inserted long branch trampolines. We detect such cases 
during boot. But, if we nop out the _mcount call sites during build 
time, we will need some other way to identify these.

- Naveen