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From:   Lukas Bulwahn <lukas.bulwahn@gmail.com>
Date:   Fri, 13 Jan 2023 14:25:17 +0100
Message-ID: <CAKXUXMyoUxKqxA3FSwFHitZkahbJqXZk4cb7LL7c9yFddFHw3Q@mail.gmail.com>
Subject: Re: linker problem with Ubuntu 18.04 tool chain: unknown architecture
 of input file `arch/arm64/boot/vmlinuz.o' is incompatible with aarch64 output
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     linux-efi@vger.kernel.org,
        Catalin Marinas <catalin.marinas@arm.com>,
        Jeremy Linton <jeremy.linton@arm.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, Jan 13, 2023 at 12:58 PM Ard Biesheuvel <ardb@kernel.org> wrote:
>
> On Fri, 13 Jan 2023 at 12:50, Lukas Bulwahn <lukas.bulwahn@gmail.com> wrote:
> >
> > Dear Ard,
> >
> > with my Ubuntu 18.04 arm gcc tool chain, I encounter this linker error
> > in my allyesconfig build:
> >
> >  LD      arch/arm64/boot/vmlinuz.efi.elf
> > aarch64-linux-gnu-ld: unknown architecture of input file
> > `arch/arm64/boot/vmlinuz.o' is incompatible with aarch64 output
> > drivers/firmware/efi/libstub/Makefile.zboot:41: recipe for target
> > 'arch/arm64/boot/vmlinuz.efi.elf' failed
> > make[1]: *** [arch/arm64/boot/vmlinuz.efi.elf] Error 1
> > arch/arm64/Makefile:173: recipe for target 'vmlinuz.efi' failed
> > make: *** [vmlinuz.efi] Error 2
> >
> > I bisected it back to happen since commit c37b830fef13 ("arm64: efi:
> > enable generic EFI compressed boot"), and it still appears with the
> > latest next-20230113 (on linux-next, I have to remove DRM_MSM as it
> > currently comes with a build error).
> >
> > The specific compiler and linker versions on my system are:
> >
> > $ aarch64-linux-gnu-ld --version
> > GNU ld (GNU Binutils for Ubuntu) 2.30
> >
> > $ aarch64-linux-gnu-gcc --version
> > aarch64-linux-gnu-gcc (Ubuntu/Linaro 7.5.0-3ubuntu1~18.04) 7.5.0
> >
> >
> > IMHO, I run pretty standard commands:
> > make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -j 32 mrproper
> > make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -j 32 allyesconfig
> > make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -j 32 all
> >
> > Let me know if you need more information.
> >
>
> Hello Lukas,
>
> This seems to mean that AArch64 ld.bfd 2.30 is not able to combine
> generic ELF objects with AArch64 ELF objects. vmlinuz.o only contains
> a compressed blob in an ELF data section, and more modern toolchains
> have no issue with this at all.
>
> Given that building allyesconfig with fairly outdated toolchains is
> not something anyone is likely to obsess about, I don't have a strong
> preference as to how we work around this, put perhaps the easiest
> approach would be for CONFIG_EFI_ZBOOT to depend on !CONFIG_LD_IS_BFD
> || CONFIG_LD_VERSION >= 23xxx here? (We'll need to check the exact
> version)

That sounds reasonable to me.

Thanks,

Lukas