From: "H.J. Lu" <hjl.tools@gmail.com>
To: Uros Bizjak <ubizjak@gmail.com>
Cc: Richard Earnshaw <Richard.Earnshaw@arm.com>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
Jan Hubicka <hubicka@ucw.cz>
Subject: Re: [PATCH 10/11] x86 - add speculation_barrier pattern
Date: Tue, 31 Jul 2018 23:15:00 -0000 [thread overview]
Message-ID: <CAMe9rOqjE08hrhZOwa2Dtm87ykwAzrMH4y=HpNn3nnysavJYRA@mail.gmail.com> (raw)
In-Reply-To: <CAFULd4Zqy91xq35kgx_Y2h2jpDC6Pc6OemUwb0LQdk2Mf44oog@mail.gmail.com>
On Sat, Jul 28, 2018 at 1:25 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Fri, Jul 27, 2018 at 11:37 AM, Richard Earnshaw
> <Richard.Earnshaw@arm.com> wrote:
>>
>> This patch adds a speculation barrier for x86, based on my
>> understanding of the required mitigation for that CPU, which is to use
>> an lfence instruction.
>>
>> This patch needs some review by an x86 expert and if adjustments are
>> needed, I'd appreciate it if they could be picked up by the port
>> maintainer. This is supposed to serve as an example of how to deploy
>> the new __builtin_speculation_safe_value() intrinsic on this
>> architecture.
>>
>> * config/i386/i386.md (unspecv): Add UNSPECV_SPECULATION_BARRIER.
>> (speculation_barrier): New insn.
>
> The implementation is OK, but someone from Intel (CC'd) should clarify
> if lfence is the correct insn.
>
I checked with our people. lfence is OK.
Thanks.
--
H.J.
next prev parent reply other threads:[~2018-07-31 23:15 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 16:39 [PATCH 0/7] Mitigation against unsafe data speculation (CVE-2017-5753) Richard Earnshaw
2018-07-09 16:39 ` [PATCH 1/7] Add __builtin_speculation_safe_value Richard Earnshaw
2018-07-23 14:28 ` Richard Earnshaw (lists)
2018-07-24 17:26 ` Richard Biener
2018-07-25 9:49 ` Richard Earnshaw (lists)
2018-07-25 10:36 ` Richard Biener
2018-07-25 12:41 ` Richard Earnshaw (lists)
2018-07-25 13:47 ` Richard Biener
2018-07-26 10:03 ` Richard Earnshaw (lists)
2018-07-26 12:41 ` Richard Biener
2018-07-26 13:06 ` Richard Earnshaw (lists)
2018-07-26 13:13 ` Richard Biener
2018-07-26 23:34 ` Joseph Myers
2018-07-27 0:46 ` Paul Koning
2018-07-27 8:59 ` Richard Earnshaw (lists)
2018-07-27 10:59 ` Joseph Myers
2018-07-25 18:03 ` Richard Earnshaw (lists)
2018-07-26 8:42 ` Richard Biener
2018-07-09 16:39 ` [PATCH 6/7] AArch64 - new pass to add conditional-branch speculation tracking Richard Earnshaw
2018-07-11 21:01 ` Jeff Law
2018-07-23 14:33 ` Richard Earnshaw (lists)
2018-07-24 21:31 ` Jeff Law
2018-07-09 16:39 ` [PATCH 4/7] AArch64 - Add new option -mtrack-speculation Richard Earnshaw
2018-07-09 16:39 ` [PATCH 2/7] Arm - add speculation_barrier pattern Richard Earnshaw
2018-07-09 16:39 ` [PATCH 5/7] AArch64 - disable CB[N]Z TB[N]Z when tracking speculation Richard Earnshaw
2018-07-09 16:39 ` [PATCH 7/7] AArch64 - use CSDB based sequences if speculation tracking is enabled Richard Earnshaw
2018-07-09 16:39 ` [PATCH 3/7] AArch64 - add speculation barrier Richard Earnshaw
2018-07-09 23:13 ` [PATCH 0/7] Mitigation against unsafe data speculation (CVE-2017-5753) Jeff Law
2018-07-10 8:49 ` Richard Earnshaw (lists)
2018-07-10 13:48 ` Bill Schmidt
2018-07-10 14:14 ` Richard Earnshaw (lists)
2018-07-10 15:44 ` Jeff Law
2018-07-10 15:42 ` Jeff Law
2018-07-10 16:43 ` Richard Earnshaw (lists)
2018-07-11 20:47 ` Jeff Law
2018-07-11 22:31 ` Richard Earnshaw (lists)
2018-07-10 7:19 ` Richard Biener
2018-07-10 8:39 ` Richard Earnshaw (lists)
2018-07-10 10:10 ` Richard Biener
2018-07-10 10:53 ` Richard Earnshaw (lists)
2018-07-10 11:22 ` Richard Biener
2018-07-10 13:43 ` Richard Earnshaw (lists)
2018-07-10 15:56 ` Jeff Law
2018-07-27 9:38 ` [PATCH 00/11] (v2) " Richard Earnshaw
2018-07-27 9:38 ` [PATCH 02/11] Arm - add speculation_barrier pattern Richard Earnshaw
2018-08-06 14:01 ` Christophe Lyon
2018-08-06 15:59 ` Richard Earnshaw (lists)
2018-07-27 9:38 ` [PATCH 03/11] AArch64 - add speculation barrier Richard Earnshaw
2018-07-27 9:38 ` [PATCH 01/11] Add __builtin_speculation_safe_value Richard Earnshaw
2018-07-27 12:11 ` Nathan Sidwell
2018-07-27 12:32 ` Richard Earnshaw (lists)
2018-07-27 12:49 ` Nathan Sidwell
2018-07-27 12:53 ` Richard Earnshaw (lists)
2018-07-30 13:16 ` Richard Biener
2018-07-31 19:25 ` H.J. Lu
2018-07-31 20:51 ` Ian Lance Taylor via gcc-patches
2018-08-01 8:50 ` Richard Earnshaw (lists)
2018-08-01 8:54 ` Jakub Jelinek
2018-08-01 9:25 ` Richard Earnshaw (lists)
2018-07-27 9:38 ` [PATCH 07/11] AArch64 - use CSDB based sequences if speculation tracking is enabled Richard Earnshaw
2018-07-27 9:38 ` [PATCH 10/11] x86 - add speculation_barrier pattern Richard Earnshaw
2018-07-28 8:25 ` Uros Bizjak
2018-07-31 23:15 ` H.J. Lu [this message]
2018-07-27 9:38 ` [PATCH 11/11] rs6000 " Richard Earnshaw
2018-07-31 22:01 ` Bill Schmidt
2018-07-31 23:31 ` Segher Boessenkool
2018-07-27 9:38 ` [PATCH 08/11] targhooks - provide an alternative hook for targets that never execute speculatively Richard Earnshaw
2018-07-30 13:17 ` Richard Biener
2018-07-27 9:38 ` [PATCH 09/11] pdp11 - example of a port not needing a speculation barrier Richard Earnshaw
2018-07-27 13:27 ` Paul Koning
2018-07-27 15:19 ` Richard Biener
2018-07-27 9:38 ` [PATCH 06/11] AArch64 - new pass to add conditional-branch speculation tracking Richard Earnshaw
2018-07-27 9:38 ` [PATCH 04/11] AArch64 - Add new option -mtrack-speculation Richard Earnshaw
2018-07-27 9:38 ` [PATCH 05/11] AArch64 - disable CB[N]Z TB[N]Z when tracking speculation Richard Earnshaw
2018-07-27 19:49 ` [PATCH 00/11] (v2) Mitigation against unsafe data speculation (CVE-2017-5753) John David Anglin
2018-08-02 18:40 ` Jeff Law
2018-08-02 20:19 ` John David Anglin
2018-08-03 9:06 ` Richard Earnshaw (lists)
2018-08-06 21:52 ` John David Anglin
2018-08-07 14:05 ` Richard Earnshaw (lists)
2018-08-07 14:56 ` John David Anglin
2018-08-03 17:26 ` Jeff Law
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAMe9rOqjE08hrhZOwa2Dtm87ykwAzrMH4y=HpNn3nnysavJYRA@mail.gmail.com' \
--to=hjl.tools@gmail.com \
--cc=Richard.Earnshaw@arm.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=hubicka@ucw.cz \
--cc=ubizjak@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).