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From: Kees Cook <keescook@chromium.org>
To: Will Deacon <will@kernel.org>
Cc: Borislav Petkov <bp@suse.de>, "H.J. Lu" <hjl.tools@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Peter Collingbourne <pcc@google.com>,
	James Morse <james.morse@arm.com>, Arnd Bergmann <arnd@arndb.de>,
	Masahiro Yamada <masahiroy@kernel.org>,
	x86@kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-arch@vger.kernel.org, linux-kbuild@vger.kernel.org,
	clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 7/9] arm64/build: Warn on orphan section placement
Date: Tue, 17 Mar 2020 16:01:16 -0700
Message-ID: <202003171558.7E1D46AED6@keescook> (raw)
In-Reply-To: <20200317215614.GB20788@willie-the-truck>

On Tue, Mar 17, 2020 at 09:56:14PM +0000, Will Deacon wrote:
> On Thu, Feb 27, 2020 at 04:22:42PM -0800, Kees Cook wrote:
> > We don't want to depend on the linker's orphan section placement
> > heuristics as these can vary between linkers, and may change between
> > versions. All sections need to be explicitly named in the linker
> > script.
> > 
> > Explicitly include debug sections when they're present. Add .eh_frame*
> > to discard as it seems that these are still generated even though
> > -fno-asynchronous-unwind-tables is being specified. Add .plt and
> > .data.rel.ro to discards as they are not actually used. Add .got.plt
> > to the image as it does appear to be mapped near .data. Finally enable
> > orphan section warnings.
> 
> Hmm, I don't understand what .got.plt is doing here. Please can you
> elaborate?

I didn't track it down, but it seems to have been present (and merged
into the kernel .data) for a while now. I can try to track this down if
you want?

-- 
Kees Cook

  reply index

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-28  0:22 [PATCH 0/9] Enable orphan section warning Kees Cook
2020-02-28  0:22 ` [PATCH 1/9] scripts/link-vmlinux.sh: Delay orphan handling warnings until final link Kees Cook
2020-03-20  2:47   ` Nicholas Piggin
2020-03-20 18:24     ` Kees Cook
2020-03-22  9:16       ` Nicholas Piggin
2020-03-22 16:00         ` Kees Cook
2020-02-28  0:22 ` [PATCH 2/9] vmlinux.lds.h: Add .gnu.version* to DISCARDS Kees Cook
2020-02-28  0:22 ` [PATCH 3/9] x86/build: Warn on orphan section placement Kees Cook
2020-02-28  0:22 ` [PATCH 4/9] x86/boot: " Kees Cook
2020-02-28  0:22 ` [PATCH 5/9] Add RUNTIME_DISCARD_EXIT to generic DISCARDS Kees Cook
2020-02-28  0:22 ` [PATCH 6/9] arm64/build: Use common DISCARDS in linker script Kees Cook
2020-03-17 21:52   ` Will Deacon
2020-02-28  0:22 ` [PATCH 7/9] arm64/build: Warn on orphan section placement Kees Cook
2020-03-17 21:56   ` Will Deacon
2020-03-17 23:01     ` Kees Cook [this message]
2020-03-17 23:10       ` Nick Desaulniers
2020-02-28  0:22 ` [PATCH 8/9] arm/build: " Kees Cook
2020-02-28  0:22 ` [PATCH 9/9] arm/boot: " Kees Cook
2020-02-28  6:51 ` [PATCH 0/9] Enable orphan section warning Sedat Dilek
2020-03-03  4:32   ` Kees Cook
2020-04-02 16:20 ` Sedat Dilek
2020-04-02 17:26   ` Kees Cook
2020-04-05 11:15     ` Sedat Dilek

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