From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Peter Zijlstra <peterz@infradead.org>,
Nick Desaulniers <ndesaulniers@google.com>
Cc: <linux-toolchains@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Steven Rostedt <rostedt@goodmis.org>,
"Jose E. Marchesi" <jemarch@gnu.org>,
Kees Cook <keescook@chromium.org>,
Florian Weimer <fweimer@redhat.com>,
Christian Brauner <christian.brauner@canonical.com>,
<nick.alcock@oracle.com>,
Segher Boessenkool <segher@kernel.crashing.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Will Deacon <will@kernel.org>
Subject: Re: Plumbers CF MCs
Date: Tue, 23 Mar 2021 19:29:01 +0000 [thread overview]
Message-ID: <a60f83d2-75da-d147-ae92-47a5b474e162@citrix.com> (raw)
In-Reply-To: <YFmoPpb5w4q1dWXz@hirez.programming.kicks-ass.net>
On 23/03/2021 08:35, Peter Zijlstra wrote:
> There also is talk about straight line speculation mitigations. for x86
> we should probably emit an INT3 after every JMP and RET. Although this
> might not be controversial and be sorted by the time Plumbers happens.
I guess this one is levied at me.
Hopefully it isn't controversial in any way. I have just had sufficient
tuits to get around to making an x86 straight line speculation feature
request to the GCC and Clang communities yet.
For the compiler folk here, the tl;dr is that indirect CALL/JMP (i.e.
function pointers, jump tables) and RET instructions may speculatively
execute the next sequential instruction(s) before taking the control
flow change into account. Having some toolchain support to deal with
this would be great, and preferable to some of the asm hackary currently
under suggestion.
~Andrew
next prev parent reply other threads:[~2021-03-23 19:37 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 20:23 Plumbers CF MCs Nick Desaulniers
2021-03-22 20:39 ` Jose E. Marchesi
2021-03-31 19:34 ` Elena Zannoni
2021-03-31 20:36 ` Nick Desaulniers
2021-04-01 7:59 ` Jose E. Marchesi
2021-04-01 20:01 ` Nick Desaulniers
2021-04-01 13:29 ` Steven Rostedt
2021-04-01 13:31 ` Steven Rostedt
2021-04-01 13:49 ` Elena Zannoni
2021-04-01 15:11 ` Miguel Ojeda
2021-04-01 20:11 ` Nick Desaulniers
2021-04-01 13:25 ` Steven Rostedt
2021-04-01 13:25 ` Steven Rostedt
2021-03-23 8:35 ` Peter Zijlstra
2021-03-23 8:45 ` Peter Zijlstra
2021-03-23 19:29 ` Andrew Cooper [this message]
2021-03-23 19:53 ` Peter Zijlstra
2021-03-23 22:12 ` Peter Zijlstra
2021-03-24 0:36 ` Steven Rostedt
2021-03-24 8:15 ` Peter Zijlstra
2021-03-23 22:23 ` Andrew Cooper
2021-03-24 8:08 ` Peter Zijlstra
2021-03-24 11:30 ` Andrew Cooper
2021-04-02 12:40 ` Segher Boessenkool
2021-03-23 22:26 ` Nick Desaulniers
2021-03-24 7:52 ` Peter Zijlstra
2021-03-24 8:47 ` Christian Brauner
2021-03-30 14:13 ` Will Deacon
2021-04-01 7:17 ` Kees Cook
2021-04-02 12:33 ` Segher Boessenkool
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