From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 10/18] arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS
Date: Thu, 16 Nov 2017 18:47:15 +0000 [thread overview]
Message-ID: <20171116184714.GD21898@arm.com> (raw)
In-Reply-To: <20171116164101.GE94341@samitolvanen.mtv.corp.google.com>
On Thu, Nov 16, 2017 at 08:41:01AM -0800, Sami Tolvanen wrote:
> On Thu, Nov 16, 2017 at 11:50:12AM +0000, Will Deacon wrote:
> > Why don't we just not do LTO if the toolchain is busted?
>
> Because LTO can not only potentially improve performance, especially
> when combined with PGO (Profile Guided Optimization), but it also
> makes it possible to enable features like Control Flow Integrity that
> can make kernel vulnerabilities more difficult to exploit:
>
> https://clang.llvm.org/docs/ControlFlowIntegrity.html
>
> > This feels like it will end up being a game of whack-a-mole as code
> > could be introduced that tickles known bugs on older toolchains.
>
> I'm not sure this is much different from dealing with older versions
> of the existing toolchain. Otherwise, we wouldn't need cc-version or
> other similar macros, for example.
I think the big difference is that we have no compelling need to support
older versions of clang or gold.
Will
next prev parent reply other threads:[~2017-11-16 18:47 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-15 21:34 [PATCH v2 00/18] Add support for clang LTO Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 01/18] kbuild: add ld-name macro and support for GNU gold Sami Tolvanen
2017-11-15 21:53 ` Kees Cook
2017-11-15 21:34 ` [PATCH v2 02/18] kbuild: fix LD_DEAD_CODE_DATA_ELIMINATION with " Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 03/18] kbuild: move gcc-version.sh to cc-version.sh and add clang support Sami Tolvanen
2017-11-15 21:48 ` Kees Cook
2017-11-15 22:06 ` Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 04/18] arm64: use -mno-implicit-float instead of -mgeneral-regs-only Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 05/18] arm64: fix -m for GNU gold Sami Tolvanen
2017-11-16 10:55 ` Yury Norov
2017-11-16 16:55 ` Nick Desaulniers
2017-11-15 21:34 ` [PATCH v2 06/18] arm64: kvm: use -fno-jump-tables with clang Sami Tolvanen
2017-11-16 11:46 ` Will Deacon
2017-11-16 16:25 ` Sami Tolvanen
2017-11-20 14:41 ` Mark Rutland
2017-11-20 14:43 ` Mark Rutland
2017-11-20 14:47 ` Ard Biesheuvel
2017-11-15 21:34 ` [PATCH v2 07/18] arm64: keep .altinstructions and .altinstr_replacement Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 08/18] arm64: don't disable ADR_PREL_PG_HI21* with ARM64_ERRATUM_843419 Sami Tolvanen
2017-11-15 22:29 ` Ard Biesheuvel
2017-11-16 11:44 ` Will Deacon
2017-11-16 16:32 ` Sami Tolvanen
2017-11-16 16:34 ` Ard Biesheuvel
2017-11-16 21:37 ` Sami Tolvanen
2017-11-16 22:14 ` Ard Biesheuvel
2017-11-16 22:25 ` Ard Biesheuvel
2017-11-16 23:09 ` Sami Tolvanen
2017-11-16 23:20 ` Ard Biesheuvel
2017-11-16 23:50 ` Sami Tolvanen
2017-11-17 9:54 ` Ard Biesheuvel
2017-11-17 18:49 ` Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 09/18] arm64: explicitly pass --no-fix-cortex-a53-843419 to GNU gold Sami Tolvanen
2017-11-16 11:47 ` Will Deacon
2017-11-16 16:35 ` Sami Tolvanen
2017-11-20 14:47 ` Mark Rutland
2017-11-20 20:35 ` Sami Tolvanen
2017-11-21 11:15 ` Mark Rutland
2017-11-15 21:34 ` [PATCH v2 10/18] arm64: add a workaround for GNU gold with ARM64_MODULE_PLTS Sami Tolvanen
2017-11-16 11:50 ` Will Deacon
2017-11-16 16:41 ` Sami Tolvanen
2017-11-16 18:47 ` Will Deacon [this message]
2017-11-15 21:34 ` [PATCH v2 11/18] arm64: make mrs_s and msr_s macros work with LTO Sami Tolvanen
2017-11-16 11:54 ` Will Deacon
2017-11-16 13:07 ` Yury Norov
2017-11-16 13:55 ` Robin Murphy
2017-11-16 21:29 ` Yury Norov
2017-11-16 22:54 ` Alex Matveev
2017-12-04 17:34 ` Nick Desaulniers
2017-11-16 13:56 ` Segher Boessenkool
2017-11-16 16:46 ` Sami Tolvanen
2017-11-16 17:01 ` Segher Boessenkool
2017-11-16 17:11 ` Sami Tolvanen
2017-11-16 16:43 ` Sami Tolvanen
2017-11-16 16:44 ` Nick Desaulniers
2017-11-16 18:14 ` Alex Matveev
2017-11-15 21:34 ` [PATCH v2 12/18] kbuild: add support for clang LTO Sami Tolvanen
2017-11-15 22:06 ` Kees Cook
2017-11-18 3:21 ` [v2,12/18] " Nicholas Piggin
2017-11-20 20:21 ` Sami Tolvanen
2017-11-21 1:01 ` Nicholas Piggin
2017-11-29 23:30 ` Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 13/18] kbuild: fix dynamic ftrace with " Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 14/18] scripts/mod: disable LTO for empty.c Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 15/18] efi/libstub: disable LTO Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 16/18] arm64: crypto: disable LTO for aes-ce-cipher.c Sami Tolvanen
2017-11-20 15:20 ` Mark Rutland
2017-11-20 15:25 ` Ard Biesheuvel
2017-11-20 21:01 ` Sami Tolvanen
2017-11-21 11:47 ` Mark Rutland
2017-11-20 20:51 ` Sami Tolvanen
2017-11-20 21:29 ` Alex Matveev
2017-11-20 21:31 ` Ard Biesheuvel
2017-11-20 22:03 ` Alex Matveev
2017-11-15 21:34 ` [PATCH v2 17/18] arm64: disable RANDOMIZE_MODULE_REGION_FULL with LTO_CLANG Sami Tolvanen
2017-11-15 21:34 ` [PATCH v2 18/18] arm64: select ARCH_SUPPORTS_LTO_CLANG Sami Tolvanen
2017-11-16 11:58 ` Will Deacon
2017-11-16 16:17 ` Sami Tolvanen
2017-11-16 16:30 ` Peter Zijlstra
2017-11-16 16:50 ` Nick Desaulniers
2017-11-16 16:59 ` Peter Zijlstra
2017-11-16 17:16 ` Nick Desaulniers
2017-11-16 17:34 ` Peter Zijlstra
2017-11-16 17:48 ` Paul E. McKenney
2017-11-16 18:16 ` Nick Desaulniers
2017-11-16 18:39 ` Paul E. McKenney
2017-11-16 18:45 ` Will Deacon
2017-11-16 19:13 ` Paul E. McKenney
2017-11-16 20:17 ` Sami Tolvanen
2017-11-20 18:05 ` Will Deacon
2017-11-20 19:25 ` Peter Zijlstra
2017-11-20 19:28 ` Peter Zijlstra
2017-11-20 20:52 ` Paul E. McKenney
2017-11-20 19:32 ` Peter Zijlstra
2017-11-20 20:53 ` Paul E. McKenney
2017-11-21 17:23 ` David Laight
2017-11-21 18:51 ` Paul E. McKenney
2017-11-23 13:42 ` Alexander Potapenko
2017-11-24 7:52 ` Dmitry Vyukov
2017-11-16 20:53 ` [PATCH v2 00/18] Add support for clang LTO Yury Norov
2017-11-16 21:38 ` Sami Tolvanen
2017-11-20 15:21 ` Mark Rutland
2017-11-20 21:04 ` Sami Tolvanen
2017-11-21 11:53 ` Mark Rutland
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