From: Linus Walleij <linus.walleij@linaro.org>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Russell King <linux@armlinux.org.uk>,
Florian Fainelli <f.fainelli@gmail.com>,
Arnd Bergmann <arnd@arndb.de>,
Abbott Liu <liuwenliang@huawei.com>,
Jian Cai <jiancai@google.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Ard Biesheuvel <ardb@kernel.org>,
linux-kbuild <linux-kbuild@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH] kbuild: Always link with '-z norelro'
Date: Tue, 17 Nov 2020 22:17:19 +0100 [thread overview]
Message-ID: <CACRpkda_u7wVr6E97WaxPC6h5SGTrmGWYBrph_0oLUAFgYnYMw@mail.gmail.com> (raw)
In-Reply-To: <20201112183839.1009297-1-natechancellor@gmail.com>
On Thu, Nov 12, 2020 at 7:41 PM Nathan Chancellor
<natechancellor@gmail.com> wrote:
> Commit 3bbd3db86470 ("arm64: relocatable: fix inconsistencies in linker
> script and options") added '-z norelro' to the arm64 Makefile when
> CONFIG_RELOCATABLE was set to help support ld.lld because ld.lld
> defaults to '-z relro' but the kernel does not use program headers or
> adhere to the section layout that is required for RELRO to work.
>
> Commit 3b92fa7485eb ("arm64: link with -z norelro regardless of
> CONFIG_RELOCATABLE") unconditionally added it to LDFLAGS_vmlinux because
> an error occurs with CONFIG_KASAN set even when CONFIG_RELOCATABLE is
> unset.
>
> As it turns out, ARM experiences the same error after CONFIG_KASAN was
> implemented, meaning that '-z norelro' needs to be added to that
> Makefile as well (multi_v7_defconfig + CONFIG_KASAN=y + LD=ld.lld):
>
> $ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- LLVM=1 zImage
> ld.lld: error: section: .exit.data is not contiguous with other relro sections
>
> To avoid playing whack-a-mole with different architectures over time,
> hoist '-z norelro' into the main Makefile. This does not affect ld.bfd
> because '-z norelro' is the default for it.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1189
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
OK makes sense, FWIW:
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Yours,
Linus Walleij
prev parent reply other threads:[~2020-11-17 21:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 18:38 [PATCH] kbuild: Always link with '-z norelro' Nathan Chancellor
2020-11-13 0:44 ` Nick Desaulniers
2020-11-13 0:53 ` Nathan Chancellor
2020-11-13 6:06 ` Ard Biesheuvel
2020-11-13 19:34 ` Nick Desaulniers
2020-11-18 23:05 ` Nick Desaulniers
2020-11-18 23:06 ` Ard Biesheuvel
2020-11-18 23:24 ` Nick Desaulniers
2020-11-19 19:33 ` Nathan Chancellor
2020-11-16 12:31 ` Catalin Marinas
2020-11-17 21:17 ` Linus Walleij [this message]
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