From: "Rémi Denis-Courmont" <remi@remlab.net>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH] Replace br return with ret
Date: Thu, 27 Jul 2023 16:55:00 +0300
Message-ID: <F3E3CFC9-4F01-45BD-9258-679D52F63D5F@remlab.net> (raw)
In-Reply-To: <667c0538-92d0-84d6-7459-ccb4194f2ea7@arm.com>
Hi,
The use of RET vs BR also has microarchitectural side effects. AFAIU, RET should always be paired with an earlier BL/BLR to avoid interfering with branch prediction.
So depending on the circumstances, either one of these should be addressed:
* Clarify that this is actually a function return , and RET should be used anyway, regardless of BTI.
* Keep BR and add BTI J landing pads where appropriate, if this wasn't really a function return.
Br,
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
next prev parent reply other threads:[~2023-07-27 13:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-27 10:26 Casey Smalley
2023-07-27 13:55 ` Rémi Denis-Courmont [this message]
2023-07-27 17:22 ` Reimar Döffinger
2023-08-04 9:14 ` Casey Smalley
2023-08-04 10:48 ` Martin Storsjö
2023-08-08 12:22 Casey Smalley
2023-08-08 17:46 ` Martin Storsjö
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=F3E3CFC9-4F01-45BD-9258-679D52F63D5F@remlab.net \
--to=remi@remlab.net \
--cc=ffmpeg-devel@ffmpeg.org \
/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
Git Inbox Mirror of the ffmpeg-devel mailing list - see https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
This inbox may be cloned and mirrored by anyone:
git clone --mirror https://master.gitmailbox.com/ffmpegdev/0 ffmpegdev/git/0.git
# If you have public-inbox 1.1+ installed, you may
# initialize and index your mirror using the following commands:
public-inbox-init -V2 ffmpegdev ffmpegdev/ https://master.gitmailbox.com/ffmpegdev \
ffmpegdev@gitmailbox.com
public-inbox-index ffmpegdev
Example config snippet for mirrors.
AGPL code for this site: git clone https://public-inbox.org/public-inbox.git