From: Catalin Marinas <catalin.marinas@arm.com>
To: Fangrui Song <maskray@google.com>
Cc: Kees Cook <keescook@chromium.org>,
Arnd Bergmann <arnd@kernel.org>, Will Deacon <will@kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Ard Biesheuvel <ardb@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Marc Zyngier <maz@kernel.org>,
David Brazdil <dbrazdil@google.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: vmlinux.lds.S: keep .entry.tramp.text section
Date: Tue, 16 Mar 2021 16:27:45 +0000 [thread overview]
Message-ID: <20210316162745.GA20565@arm.com> (raw)
In-Reply-To: <20210316104530.GA7309@arm.com>
On Tue, Mar 16, 2021 at 10:45:32AM +0000, Catalin Marinas wrote:
> On Fri, Feb 26, 2021 at 08:32:57PM -0800, Fangrui Song wrote:
> > On 2021-02-26, Kees Cook wrote:
> > > 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 diagnostic is from an ASSERT in arch/arm64/kernel/vmlinux.lds
> >
> > ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == (1 << 16),
> > "Entry trampoline text too big")
>
> Can we not change the ASSERT to be <= PAGE_SIZE instead?
Ah, that won't work as I suspect we still need the trampoline section.
Arnd, do you know why this section disappears? I did a simple test with
defconfig + LD_DEAD_CODE_DATA_ELIMINATION and the trampoline section is
still around.
--
Catalin
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next prev parent reply other threads:[~2021-03-16 16:29 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
2021-02-27 4:32 ` Fangrui Song
2021-03-16 10:45 ` Catalin Marinas
2021-03-16 16:27 ` Catalin Marinas [this message]
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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