From: Will Deacon <will@kernel.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: "Catalin Marinas" <catalin.marinas@arm.com>,
kernel-team <kernel-team@android.com>,
"Peter Smith" <Peter.Smith@arm.com>,
clang-built-linux <clang-built-linux@googlegroups.com>,
stable <stable@vger.kernel.org>,
"Ard Biesheuvel" <ardb@kernel.org>,
"Fāng-ruì Sòng" <maskray@google.com>,
"Quentin Perret" <qperret@google.com>,
"Alan Modra" <amodra@gmail.com>,
"kernelci . org bot" <bot@kernelci.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: link with -z norelro for LLD or aarch64-elf
Date: Thu, 17 Dec 2020 12:01:19 +0000 [thread overview]
Message-ID: <20201217120118.GC17544@willie-the-truck> (raw)
In-Reply-To: <20201217004051.1247544-1-ndesaulniers@google.com>
On Wed, Dec 16, 2020 at 04:40:51PM -0800, Nick Desaulniers wrote:
> With newer GNU binutils, linking with BFD produces warnings for vmlinux:
> aarch64-linux-gnu-ld: warning: -z norelro ignored
>
> BFD can produce this warning when the target emulation mode does not
> support RELRO relocation types, and -z relro or -z norelro is passed.
>
> Alan Modra clarifies:
> The default linker emulation for an aarch64-linux ld.bfd is
> -maarch64linux, the default for an aarch64-elf linker is
> -maarch64elf. They are not equivalent. If you choose -maarch64elf
> you get an emulation that doesn't support -z relro.
>
> The ARCH=arm64 kernel prefers -maarch64elf, but may fall back to
> -maarch64linux based on the toolchain configuration.
>
> LLD will always create RELRO relocation types regardless of target
> emulation.
>
> To avoid the above warning when linking with BFD, pass -z norelro only
> when linking with LLD or with -maarch64linux.
Given that, prior to 3b92fa7485eb, we used to pass '-z norelro' if
CONFIG_RELOCATABLE then was this already broken with the ELF toolchain?
Will
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: "kernelci . org bot" <bot@kernelci.org>,
"Fāng-ruì Sòng" <maskray@google.com>,
"Quentin Perret" <qperret@google.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Alan Modra" <amodra@gmail.com>,
"Peter Smith" <Peter.Smith@arm.com>,
stable <stable@vger.kernel.org>,
linux-kernel@vger.kernel.org,
clang-built-linux <clang-built-linux@googlegroups.com>,
kernel-team <kernel-team@android.com>,
"Ard Biesheuvel" <ardb@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: link with -z norelro for LLD or aarch64-elf
Date: Thu, 17 Dec 2020 12:01:19 +0000 [thread overview]
Message-ID: <20201217120118.GC17544@willie-the-truck> (raw)
In-Reply-To: <20201217004051.1247544-1-ndesaulniers@google.com>
On Wed, Dec 16, 2020 at 04:40:51PM -0800, Nick Desaulniers wrote:
> With newer GNU binutils, linking with BFD produces warnings for vmlinux:
> aarch64-linux-gnu-ld: warning: -z norelro ignored
>
> BFD can produce this warning when the target emulation mode does not
> support RELRO relocation types, and -z relro or -z norelro is passed.
>
> Alan Modra clarifies:
> The default linker emulation for an aarch64-linux ld.bfd is
> -maarch64linux, the default for an aarch64-elf linker is
> -maarch64elf. They are not equivalent. If you choose -maarch64elf
> you get an emulation that doesn't support -z relro.
>
> The ARCH=arm64 kernel prefers -maarch64elf, but may fall back to
> -maarch64linux based on the toolchain configuration.
>
> LLD will always create RELRO relocation types regardless of target
> emulation.
>
> To avoid the above warning when linking with BFD, pass -z norelro only
> when linking with LLD or with -maarch64linux.
Given that, prior to 3b92fa7485eb, we used to pass '-z norelro' if
CONFIG_RELOCATABLE then was this already broken with the ELF toolchain?
Will
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next prev parent reply other threads:[~2020-12-17 12:02 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-16 17:53 [PATCH] arm64: link with -z norelro regardless of CONFIG_RELOCATABLE Nick Desaulniers
2020-10-16 17:53 ` Nick Desaulniers
2020-10-20 17:57 ` Will Deacon
2020-10-20 17:57 ` Will Deacon
2020-10-20 20:16 ` Nick Desaulniers
2020-10-20 20:16 ` Nick Desaulniers
2020-10-21 6:58 ` Ard Biesheuvel
2020-10-21 6:58 ` Ard Biesheuvel
2020-12-14 21:44 ` Nick Desaulniers
2020-12-14 21:44 ` Nick Desaulniers
2020-12-14 23:18 ` Alan Modra
2020-12-14 23:18 ` Alan Modra
2020-12-14 23:33 ` Nick Desaulniers
2020-12-14 23:33 ` Nick Desaulniers
2020-12-17 0:40 ` [PATCH] arm64: link with -z norelro for LLD or aarch64-elf Nick Desaulniers
2020-12-17 0:40 ` Nick Desaulniers
2020-12-17 12:01 ` Will Deacon [this message]
2020-12-17 12:01 ` Will Deacon
2020-12-17 21:07 ` Nick Desaulniers
2020-12-17 21:07 ` Nick Desaulniers
2020-12-18 0:24 ` [PATCH v2] " Nick Desaulniers
2020-12-18 0:24 ` Nick Desaulniers
2020-12-18 2:36 ` Nathan Chancellor
2020-12-18 2:36 ` Nathan Chancellor
2021-01-05 12:26 ` Catalin Marinas
2021-01-05 12:26 ` Catalin Marinas
2020-12-17 19:29 ` [PATCH] " Ard Biesheuvel
2020-12-17 19:29 ` Ard Biesheuvel
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