Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220218081209.354383-1-maskray@google.com>
In-Reply-To: <20220218081209.354383-1-maskray@google.com>
From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Fri, 18 Feb 2022 09:17:46 +0100
Message-ID: <CAMj1kXGZuOWOPEHv0YSM4GseG2PnTgS8mSLXQ+imo-TN7MmvaQ@mail.gmail.com>
Subject: Re: [PATCH] arm64 module: remove (NOLOAD)
To:     Fangrui Song <maskray@google.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        llvm@lists.linux.dev
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, 18 Feb 2022 at 09:12, Fangrui Song <maskray@google.com> wrote:
>
> On ELF, (NOLOAD) sets the section type to SHT_NOBITS[1]. It is conceptually
> inappropriate for .plt and .text.* sections which are always
> SHT_PROGBITS.
>
> In GNU ld, if PLT entries are needed, .plt will be SHT_PROGBITS anyway
> and (NOLOAD) will be essentially ignored. In ld.lld, since
> https://reviews.llvm.org/D118840 ("[ELF] Support (TYPE=<value>) to
> customize the output section type"), ld.lld will report a `section type
> mismatch` error. Just remove (NOLOAD) to fix the error.
>
> [1] https://lld.llvm.org/ELF/linker_script.html As of today, "The
> section should be marked as not loadable" on
> https://sourceware.org/binutils/docs/ld/Output-Section-Type.html is
> outdated for ELF.

This patch lacks a SOB line.

With one added,

Acked-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  arch/arm64/include/asm/module.lds.h | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/include/asm/module.lds.h b/arch/arm64/include/asm/module.lds.h
> index a11ccadd47d2..094701ec5500 100644
> --- a/arch/arm64/include/asm/module.lds.h
> +++ b/arch/arm64/include/asm/module.lds.h
> @@ -1,8 +1,8 @@
>  SECTIONS {
>  #ifdef CONFIG_ARM64_MODULE_PLTS
> -       .plt 0 (NOLOAD) : { BYTE(0) }
> -       .init.plt 0 (NOLOAD) : { BYTE(0) }
> -       .text.ftrace_trampoline 0 (NOLOAD) : { BYTE(0) }
> +       .plt 0 : { BYTE(0) }
> +       .init.plt 0 : { BYTE(0) }
> +       .text.ftrace_trampoline 0 : { BYTE(0) }
>  #endif
>
>  #ifdef CONFIG_KASAN_SW_TAGS
> --
> 2.35.1.265.g69c8d7142f-goog
>