linux-kernel - Re: [PATCH v7 02/17] kbuild: add support for Clang LTO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20201120202935.GA1220359@ubuntu-m3-large-x86>
Date:   Fri, 20 Nov 2020 13:29:35 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Kees Cook <keescook@...omium.org>
Cc:     Sami Tolvanen <samitolvanen@...gle.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Will Deacon <will@...nel.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>, linux-pci@...r.kernel.org
Subject: Re: [PATCH v7 02/17] kbuild: add support for Clang LTO

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.

Cheers,
Nathan