From: Kees Cook <keescook@chromium.org>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Fangrui Song <maskray@google.com>, Arnd Bergmann <arnd@arndb.de>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-kernel@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
David Brazdil <dbrazdil@google.com>,
Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: vmlinux.lds.S: keep .entry.tramp.text section
Date: Fri, 26 Feb 2021 12:59:17 -0800 [thread overview]
Message-ID: <202102261256.AF256702@keescook> (raw)
In-Reply-To: <20210226140352.3477860-1-arnd@kernel.org>
On Fri, Feb 26, 2021 at 03:03:39PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> When building with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION,
> I sometimes see an assertion
>
> ld.lld: error: Entry trampoline text too big
Heh, "too big" seems a weird report for having it discarded. :)
Any idea on this Fangrui?
( I see this is https://github.com/ClangBuiltLinux/linux/issues/1311 )
>
> This happens when any reference to the trampoline is discarded at link
> time. Marking the section as KEEP() avoids the assertion, but I have
> not figured out whether this is the correct solution for the underlying
> problem.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
As a work-around, it seems fine to me.
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> arch/arm64/kernel/vmlinux.lds.S | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
> index 926cdb597a45..c5ee9d5842db 100644
> --- a/arch/arm64/kernel/vmlinux.lds.S
> +++ b/arch/arm64/kernel/vmlinux.lds.S
> @@ -96,7 +96,7 @@ jiffies = jiffies_64;
> #define TRAMP_TEXT \
> . = ALIGN(PAGE_SIZE); \
> __entry_tramp_text_start = .; \
> - *(.entry.tramp.text) \
> + KEEP(*(.entry.tramp.text)) \
> . = ALIGN(PAGE_SIZE); \
> __entry_tramp_text_end = .;
> #else
> --
> 2.29.2
>
--
Kees Cook
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next prev parent reply other threads:[~2021-02-26 21:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 14:03 [PATCH] arm64: vmlinux.lds.S: keep .entry.tramp.text section Arnd Bergmann
2021-02-26 20:59 ` Kees Cook [this message]
2021-02-27 4:32 ` Fangrui Song
2021-03-16 10:45 ` Catalin Marinas
2021-03-16 16:27 ` Catalin Marinas
2021-03-16 16:39 ` Arnd Bergmann
2021-03-16 19:09 ` Catalin Marinas
2021-06-02 19:32 ` Kees Cook
2021-06-03 12:07 ` Catalin Marinas
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