From: Segher Boessenkool <segher@kernel.crashing.org>
To: Fangrui Song <maskray@google.com>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] Replace __toc_start + 0x8000 with .TOC.
Date: Sun, 7 Mar 2021 00:23:36 -0600 [thread overview]
Message-ID: <20210307062336.GD29191@gate.crashing.org> (raw)
In-Reply-To: <20210307051433.2756645-1-maskray@google.com>
Hi!
On Sat, Mar 06, 2021 at 09:14:33PM -0800, Fangrui Song wrote:
> TOC relocations are like GOT relocations on other architectures.
> However, unlike other architectures, GNU ld's ppc64 port defines .TOC.
> relative to the .got output section instead of the linker synthesized
> .got input section. LLD defines .TOC. as the .got input section plus
> 0x8000. When CONFIG_PPC_OF_BOOT_TRAMPOLINE=y,
> arch/powerpc/kernel/prom_init.o is built, and LLD computed .TOC. can be
> different from __toc_start defined by the linker script.
>
> Simplify kernel_toc_addr with asm label .TOC. so that we can get rid of
> __toc_start.
>
> With this change, powernv_defconfig with CONFIG_PPC_OF_BOOT_TRAMPOLINE=y
> is bootable with LLD. There is still an untriaged issue with Alexey's
> configuration.
Do you have any explanation why this *does* work, while the original
doesn't? Some explanation that says *what* is wrong. To me it doesn't
look like the kernel script is.
Segher
next prev parent reply other threads:[~2021-03-07 6:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-07 5:14 [PATCH] Replace __toc_start + 0x8000 with .TOC Fangrui Song
2021-03-07 6:23 ` Segher Boessenkool [this message]
2021-03-07 6:31 ` Fāng-ruì Sòng
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