Re: [PATCH] kbuild: rebuild GCC plugins when the compiler is upgraded

[Josh Poimboeuf]

On Sat, Mar 06, 2021 at 11:18:31AM +0900, Masahiro Yamada wrote:
> On Sat, Mar 6, 2021 at 10:28 AM Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> >
> > On Thu, Mar 04, 2021 at 08:25:00PM -0600, Josh Poimboeuf wrote:
> > > On Thu, Mar 04, 2021 at 03:37:14PM -0800, Linus Torvalds wrote:
> > > > On Thu, Mar 4, 2021 at 3:20 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > > > >
> > > > > This seems fine to me, but I want to make sure Josh has somewhere to
> > > > > actually go with this. Josh, does this get you any closer?
> > >
> > > No, this doesn't seem to help me at all.
> > >
> > > > > It sounds like the plugins need to move to another location for
> > > > > packaged kernels?
> > > >
> > > > Well, it might be worth extending the stuff that gets installed with
> > > > /lib/modules/<kernel-version>/ with enough information and
> > > > infrastruvcture to then build any external modules.
> > >
> > > The gcc plugins live in scripts/, which get installed by "make
> > > modules_install" already.  So the plugins' source and makefiles are in
> > > /lib/modules/<kernel-version>/build/scripts/gcc-plugins.
> > >
> > > So everything needed for building the plugins is already there.  We just
> > > need the kernel makefiles to rebuild the plugins locally, when building
> > > an external module.
> >
> > This seems to work with very limited testing...  Based on top of
> > Masahiro's recent patch:
> >
> >   https://lkml.kernel.org/r/CAK7LNARHoTnZ3gAvHgnYB4n-wYuboxC10A6zURh1ODGhxWd2yA@xxxxxxxxxxxxxx
> 
> Is this a bad coding contest?
> 
> I am not asking you to add ugly ifeq or whatever
> hacks to say "this worked for me".
> 
> Please feel free to do this in the fedora kernel,
> but do not send it to upstream.
> 
> Sorry, I really do not want to see hacks like this any more.

Geez, that's a bit harsh.  I never claimed to be a brilliant makefile
coder.  Do you have any constructive feedback for improving the patch?

> Remember, how badly objtool was integrated in the build system,
> and you even blocked me from fixing that.

I have no idea what you're talking about, nor how it would be relevant
to this patch.

-- 
Josh