linux-kernel - Re: [PATCH v4 0/7] x86/boot: Remove runtime relocations from compressed kernel

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Message-ID: <20200714202100.GB902932@rani.riverdale.lan>
Date:   Tue, 14 Jul 2020 16:21:00 -0400
From:   Arvind Sankar <nivedita@...m.mit.edu>
To:     Sedat Dilek <sedat.dilek@...il.com>
Cc:     Arvind Sankar <nivedita@...m.mit.edu>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Fangrui Song <maskray@...gle.com>,
        Dmitry Golovin <dima@...ovin.in>,
        Clang-Built-Linux ML <clang-built-linux@...glegroups.com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Daniel Kiper <daniel.kiper@...cle.com>,
        Kees Cook <keescook@...omium.org>,
        Nathan Chancellor <natechancellor@...il.com>,
        Arnd Bergmann <arnd@...db.de>,
        "H . J . Lu" <hjl@...rceware.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 0/7] x86/boot: Remove runtime relocations from
 compressed kernel

On Tue, Jul 14, 2020 at 10:08:04PM +0200, Sedat Dilek wrote:
> > >
> > > In any case, I think the right fix here would be to add -pie and
> > > --no-dynamic-linker to LDFLAGS_vmlinux instead of KBUILD_LDFLAGS.
> >
> > Hmm, you might be right with moving to LDFLAGS_vmlinux.
> >
> 
> We will need the "ifndef CONFIG_LD_IS_LLD" as -r and -pie cannot be
> used together.
> Is that the or not the fact when moving to LDFLAGS_vmlinux?

LDFLAGS_vmlinux will only be used to link boot/compressed/vmlinux,
whereas KBUILD_LDFLAGS is used for all linker invocations, and in
particular the little link to do the modversions stuff ends up using it.

So once we move -pie --no-dynamic-linker to the more correct
LDFLAGS_vmlinux and/or stop modversions running, we'll be fine. Being
able to use -pie with lld is one of the goals of this series.

> 
> I cannot test as I modified my local Git and re-invoking my
> build-script is doing a whole new build-dance.
> 
> - Sedat -