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

From: Sedat Dilek <sedat.dilek@gmail.com>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, Nick Desaulniers <ndesaulniers@google.com>,
	Fangrui Song <maskray@google.com>,
	Dmitry Golovin <dima@golovin.in>,
	Clang-Built-Linux ML <clang-built-linux@googlegroups.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Daniel Kiper <daniel.kiper@oracle.com>,
	Kees Cook <keescook@chromium.org>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>, "H . J . Lu" <hjl@sourceware.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 0/7] x86/boot: Remove runtime relocations from compressed kernel
Date: Tue, 14 Jul 2020 20:33:19 +0200	[thread overview]
Message-ID: <CA+icZUWip6xAFdTiLNWT4QHS0R6bQuCZ6W7dWd+UbbZGnBBh4w@mail.gmail.com> (raw)
In-Reply-To: <CA+icZUWHdsk9+wkTZOdDghM7pRZyk2vHgxpYx62vPooqohzbYw@mail.gmail.com>

On Tue, Jul 14, 2020 at 8:30 PM Sedat Dilek <sedat.dilek@gmail.com> wrote:
>
> > I did a full new build...
> >
> > ...and it fails with ld.lld-11 as linker:
> >
> > ld.lld-11 -m elf_x86_64 -pie  --no-dynamic-linker -r -o
> > arch/x86/boot/compressed/.tmp_misc.o arch/x86/boot/compressed/misc.o
> > -T arch/x86/boot/compressed/.tmp_misc.ver; mv -f
> > arch/x86/boot/compressed/.tmp_misc.o arch/x86/boot/compressed/misc.o;
> > rm -f arch/x86/boot/compressed/.tmp_misc.ver; fi
> > *** ld.lld-11: error: -r and -pie may not be used together ***
> > make[5]: *** [scripts/Makefile.build:281:
> > arch/x86/boot/compressed/misc.o] Error 1
> >
> > It's annoying to fail on the last minutes of a build.
> > Sorry for being very honest.
> >
>
> I applied this diff...
>
> $ git diff arch/x86/boot/compressed/Makefile
> diff --git a/arch/x86/boot/compressed/Makefile
> b/arch/x86/boot/compressed/Makefile
> index 789d5d14d8b0..9ba52a656838 100644
> --- a/arch/x86/boot/compressed/Makefile
> +++ b/arch/x86/boot/compressed/Makefile
> @@ -51,7 +51,10 @@ UBSAN_SANITIZE :=n
>  KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
>  # Compressed kernel should be built as PIE since it may be loaded at any
>  # address by the bootloader.
> +# LLD linker does not allow -r and -pie options to be used together.
> +ifndef CONFIG_LD_IS_LLD
>  KBUILD_LDFLAGS += -pie $(call ld-option, --no-dynamic-linker)
> +endif
>  LDFLAGS_vmlinux := -T
>
>  hostprogs      := mkpiggy
>
> ...and was able to build, assemble, link arch/x86/boot/compressed/*.
>

I checked my last succesfull build without your patchset:

$ grep no-dynamic-linker build-log_5.8.0-rc5-1-amd64-llvm11-ias.txt
[ EMPTY ]

- Sedat -