From: Peter Collingbourne <pcc@google.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: clang-built-linux <clang-built-linux@googlegroups.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2] arm64: Add support for relocating the kernel with RELR relocations
Date: Mon, 29 Jul 2019 13:00:51 -0700 [thread overview]
Message-ID: <CAMn1gO4KUq_Q39Rj3FWs6bG8BkCpGhS7gqYtBxi9EtrX=J9uTg@mail.gmail.com> (raw)
In-Reply-To: <20190712193846.174893-1-pcc@google.com>
On Fri, Jul 12, 2019 at 12:39 PM Peter Collingbourne <pcc@google.com> wrote:
>
> RELR is a relocation packing format for relative relocations.
> The format is described in a generic-abi proposal:
> https://groups.google.com/d/topic/generic-abi/bX460iggiKg/discussion
>
> The LLD linker can be instructed to pack relocations in the RELR
> format by passing the flag --pack-dyn-relocs=relr.
>
> This patch adds a new config option, CONFIG_RELR. Enabling this option
> instructs the linker to pack vmlinux's relative relocations in the RELR
> format, and causes the kernel to apply the relocations at startup along
> with the RELA relocations. RELA relocations still need to be applied
> because the linker will emit RELA relative relocations if they are
> unrepresentable in the RELR format (i.e. address not a multiple of 2).
>
> Enabling CONFIG_RELR reduces the size of a defconfig kernel image
> with CONFIG_RANDOMIZE_BASE by 3.5MB/16% uncompressed, or 550KB/5%
> compressed (lz4).
>
> Signed-off-by: Peter Collingbourne <pcc@google.com>
> Tested-by: Nick Desaulniers <ndesaulniers@google.com>
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> Changes in v2:
> - Reverted change to RELA processing
> - Added more comments, as requested by Nick and Will
> - Added a feature test for NM and OBJCOPY
> - Made CONFIG_RELR=y the default if the tools support it
Ping.
Peter
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next prev parent reply other threads:[~2019-07-29 20:01 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-05 8:02 [PATCH] arm64: Add support for relocating the kernel with RELR relocations Peter Collingbourne
2019-07-08 18:02 ` Nick Desaulniers
2019-07-09 22:04 ` Peter Collingbourne
2019-07-09 23:13 ` Nick Desaulniers
2019-07-12 19:40 ` Peter Collingbourne
2019-07-10 16:21 ` Will Deacon
2019-07-12 19:40 ` Peter Collingbourne
2019-07-10 23:14 ` Nick Desaulniers
2019-07-12 19:40 ` Peter Collingbourne
2019-07-12 19:33 ` [PATCH v2] arm64: Add support for relocating the kernel with RELR Peter Collingbourne
2019-07-12 19:38 ` [PATCH v2] arm64: Add support for relocating the kernel with RELR relocations Peter Collingbourne
2019-07-29 20:00 ` Peter Collingbourne [this message]
2019-07-31 16:48 ` Will Deacon
2019-08-01 1:19 ` Peter Collingbourne
2019-08-01 1:18 ` [PATCH v3] " Peter Collingbourne
2019-08-01 12:05 ` Will Deacon
2019-08-01 17:51 ` Peter Collingbourne
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