[PATCH v2 1/2] kbuild: Hoist '--orphan-handling' into Kconfig

[Masahiro Yamada]

On Sat, Nov 21, 2020 at 9:08 AM Kees Cook <keescook at chromium.org> wrote:
>
> On Thu, Nov 19, 2020 at 01:46:56PM -0700, Nathan Chancellor wrote:
> > Currently, '--orphan-handling=warn' is spread out across four different
> > architectures in their respective Makefiles, which makes it a little
> > unruly to deal with in case it needs to be disabled for a specific
> > linker version (in this case, ld.lld 10.0.1).
> >
> > To make it easier to control this, hoist this warning into Kconfig and
> > the main Makefile so that disabling it is simpler, as the warning will
> > only be enabled in a couple places (main Makefile and a couple of
> > compressed boot folders that blow away LDFLAGS_vmlinx) and making it
> > conditional is easier due to Kconfig syntax. One small additional
> > benefit of this is saving a call to ld-option on incremental builds
> > because we will have already evaluated it for CONFIG_LD_ORPHAN_WARN.
> >
> > To keep the list of supported architectures the same, introduce
> > CONFIG_ARCH_WANT_LD_ORPHAN_WARN, which an architecture can select to
> > gain this automatically after all of the sections are specified and size
> > asserted. A special thanks to Kees Cook for the help text on this
> > config.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1187
> > Acked-by: Kees Cook <keescook at chromium.org>
> > Acked-by: Michael Ellerman <mpe at ellerman.id.au> (powerpc)
> > Reviewed-by: Nick Desaulniers <ndesaulniers at google.com>
> > Tested-by: Nick Desaulniers <ndesaulniers at google.com>
> > Signed-off-by: Nathan Chancellor <natechancellor at gmail.com>
>
> Masahiro, do you want to take these to get them to Linus for v5.10? I
> can send them if you'd prefer.
>



Sorry for the delay.

Applied to linux-kbuild.





> -Kees
>
> --
> Kees Cook
>
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-- 
Best Regards
Masahiro Yamada