From: Kees Cook <keescook@chromium.org>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Sami Tolvanen <samitolvanen@google.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Will Deacon <will@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
linux-arch <linux-arch@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-pci@vger.kernel.org
Subject: Re: [PATCH v7 02/17] kbuild: add support for Clang LTO
Date: Fri, 20 Nov 2020 12:43:14 -0800 [thread overview]
Message-ID: <202011201241.B159562D7@keescook> (raw)
In-Reply-To: <20201120202935.GA1220359@ubuntu-m3-large-x86>
On Fri, Nov 20, 2020 at 01:29:35PM -0700, Nathan Chancellor wrote:
> On Fri, Nov 20, 2020 at 11:47:21AM -0800, Kees Cook wrote:
> > On Fri, Nov 20, 2020 at 08:23:11AM -0800, Sami Tolvanen wrote:
> > > Changing the ThinLTO config to a choice and moving it after the main
> > > LTO config sounds like a good idea to me. I'll see if I can change
> > > this in v8. Thanks!
> >
> > Originally, I thought this might be a bit ugly once GCC LTO is added,
> > but this could be just a choice like we're done for the stack
> > initialization. Something like an "LTO" choice of NONE, CLANG_FULL,
> > CLANG_THIN, and in the future GCC, etc.
>
> Having two separate choices might be a little bit cleaner though? One
> for the compiler (LTO_CLANG versus LTO_GCC) and one for the type
> (THINLTO versus FULLLTO). The type one could just have a "depends on
> CC_IS_CLANG" to ensure it only showed up when needed.
Right, that's how the stack init choice works. Kconfigs that aren't
supported by the compiler won't be shown. I.e. after Sami's future
patch, the only choice for GCC will be CONFIG_LTO_NONE. But building
under Clang, it would offer CONFIG_LTO_NONE, CONFIG_LTO_CLANG_FULL,
CONFIG_LTO_CLANG_THIN, or something.
(and I assume CONFIG_LTO would be def_bool y, depends on !LTO_NONE)
--
Kees Cook
next prev parent reply other threads:[~2020-11-20 20:43 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-18 22:07 [PATCH v7 00/17] Add support for Clang LTO Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 01/17] tracing: move function tracer options to Kconfig Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 02/17] kbuild: add support for Clang LTO Sami Tolvanen
2020-11-18 23:48 ` Nick Desaulniers
2020-11-20 16:23 ` Sami Tolvanen
2020-11-20 19:47 ` Kees Cook
2020-11-20 20:29 ` Nathan Chancellor
2020-11-20 20:43 ` Kees Cook [this message]
2020-11-20 20:58 ` Sami Tolvanen
2020-11-20 23:59 ` Kees Cook
2020-11-21 1:46 ` Sami Tolvanen
2020-11-21 20:11 ` Kees Cook
2020-11-18 22:07 ` [PATCH v7 03/17] kbuild: lto: fix module versioning Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 04/17] kbuild: lto: limit inlining Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 05/17] kbuild: lto: merge module sections Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 06/17] kbuild: lto: remove duplicate dependencies from .mod files Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 07/17] init: lto: ensure initcall ordering Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 08/17] init: lto: fix PREL32 relocations Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 09/17] PCI: Fix PREL32 relocations for LTO Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 10/17] modpost: lto: strip .lto from module names Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 11/17] scripts/mod: disable LTO for empty.c Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 12/17] efi/libstub: disable LTO Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 13/17] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 14/17] arm64: vdso: disable LTO Sami Tolvanen
2020-11-30 11:52 ` Will Deacon
2020-11-30 23:44 ` Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 15/17] KVM: arm64: disable LTO for the nVHE directory Sami Tolvanen
2020-11-23 10:21 ` David Brazdil
2020-11-23 18:34 ` Sami Tolvanen
2020-11-18 22:07 ` [PATCH v7 16/17] arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS Sami Tolvanen
2020-11-30 11:59 ` Will Deacon
2020-11-18 22:07 ` [PATCH v7 17/17] arm64: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen
2020-11-30 12:00 ` Will Deacon
2020-11-18 23:42 ` [PATCH v7 00/17] Add support for Clang LTO Nick Desaulniers
2020-11-20 10:29 ` Ard Biesheuvel
2020-11-20 20:19 ` Nick Desaulniers
2020-11-20 23:30 ` Ard Biesheuvel
2020-11-20 23:53 ` Nick Desaulniers
2020-11-21 7:35 ` Ard Biesheuvel
2020-11-21 11:40 ` Marc Zyngier
2020-11-21 3:14 ` Nathan Chancellor
2020-11-20 4:04 ` Josh Poimboeuf
2020-11-20 20:25 ` Sami Tolvanen
2020-11-30 12:01 ` Will Deacon
2020-12-01 17:31 ` Kees Cook
2020-12-01 19:51 ` Nick Desaulniers
2020-12-01 21:38 ` Sami Tolvanen
2020-12-02 2:42 ` Masahiro Yamada
2020-12-02 5:46 ` Sami Tolvanen
2020-12-02 18:54 ` Kees Cook
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