Subject: Re: [PATCH] powerpc: Avoid clang warnings around setjmp and longjmp

From: Nathan Chancellor <[email-masked]>
Date: Mon, 2 Sep 2019 22:55:53 -0700

On Thu, Aug 29, 2019 at 09:59:48AM +0000, David Laight wrote:
> From: Nathan Chancellor
> > Sent: 28 August 2019 19:45
> ...
> > However, I think that -fno-builtin-* would be appropriate here because
> > we are providing our own setjmp implementation, meaning clang should not
> > be trying to do anything with the builtin implementation like building a
> > declaration for it.
> 
> Isn't implementing setjmp impossible unless you tell the compiler that
> you function is 'setjmp-like' ?

No idea, PowerPC is the only architecture that does such a thing.

https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/tree/arch/powerpc/kernel/misc.S#n43

Goes back all the way to before git history (all the way to ppc64's
addition actually):

https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=61542216fa90397a2e70c46583edf26bc81994df

https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/arch/ppc64/xmon/setjmp.c?id=5f12b0bff93831620218e8ed3970903ecb7861ce

I would just like this warning fixed given that PowerPC builds with
-Werror by default so it is causing a build failure in our CI.

Cheers,
Nathan