Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Tue, 1 Dec 2020 11:51:41 -0800
From: Nick Desaulniers <ndesaulniers@...gle.com>
To: Kees Cook <keescook@...omium.org>
Cc: Will Deacon <will@...nel.org>, Sami Tolvanen <samitolvanen@...gle.com>, 
	Masahiro Yamada <masahiroy@...nel.org>, Steven Rostedt <rostedt@...dmis.org>, 
	Josh Poimboeuf <jpoimboe@...hat.com>, Peter Zijlstra <peterz@...radead.org>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, "Paul E. McKenney" <paulmck@...nel.org>, 
	clang-built-linux <clang-built-linux@...glegroups.com>, 
	Kernel Hardening <kernel-hardening@...ts.openwall.com>, 
	linux-arch <linux-arch@...r.kernel.org>, 
	Linux ARM <linux-arm-kernel@...ts.infradead.org>, 
	Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>, 
	PCI <linux-pci@...r.kernel.org>
Subject: Re: [PATCH v7 00/17] Add support for Clang LTO

On Tue, Dec 1, 2020 at 9:31 AM Kees Cook <keescook@...omium.org> wrote:
>
> On Mon, Nov 30, 2020 at 12:01:31PM +0000, Will Deacon wrote:
> > Hi Sami,
> >
> > On Wed, Nov 18, 2020 at 02:07:14PM -0800, Sami Tolvanen wrote:
> > > This patch series adds support for building the kernel with Clang's
> > > Link Time Optimization (LTO). In addition to performance, the primary
> > > motivation for LTO is to allow Clang's Control-Flow Integrity (CFI) to
> > > be used in the kernel. Google has shipped millions of Pixel devices
> > > running three major kernel versions with LTO+CFI since 2018.
> > >
> > > Most of the patches are build system changes for handling LLVM bitcode,
> > > which Clang produces with LTO instead of ELF object files, postponing
> > > ELF processing until a later stage, and ensuring initcall ordering.
> > >
> > > Note that v7 brings back arm64 support as Will has now staged the
> > > prerequisite memory ordering patches [1], and drops x86_64 while we work
> > > on fixing the remaining objtool warnings [2].
> >
> > Sounds like you're going to post a v8, but that's the plan for merging
> > that? The arm64 parts look pretty good to me now.
>
> I haven't seen Masahiro comment on this in a while, so given the review
> history and its use (for years now) in Android, I will carry v8 (assuming
> all is fine with it) it in -next unless there are objections.

I had some minor stylistic feedback on the Kconfig changes; I'm happy
for you to land the bulk of the changes and then I follow up with
patches to the Kconfig after.
-- 
Thanks,
~Nick Desaulniers

Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.