From: Richard Earnshaw <Richard.Earnshaw@foss.arm.com>
To: Florian Mayer <fmayer@google.com>, gcc@gcc.gnu.org
Cc: Fangrui Song <maskray@google.com>, Evgenii Stepanov <eugenis@google.com>
Subject: Re: .eh_frame augmentation character for MTE stack tagging
Date: Mon, 6 Jun 2022 12:00:38 +0100 [thread overview]
Message-ID: <00728f04-2b84-13a3-2ebb-34f5953d28a5@foss.arm.com> (raw)
In-Reply-To: <CAJAyTCDHRLfxUWARpH5fzis9sqWtuF1PV5MsjLuyYU3LxPx9cA@mail.gmail.com>
On 04/06/2022 00:52, Florian Mayer via Gcc wrote:
> Hey!
>
> We are in the process of implementing MTE (Memory Tagging Extension)
> stack tagging in LLVM. To support stack tagging in combination with
> exceptions, we need to make sure that the unwinder will untag stack
> frames, to avoid leaving behind stale tags. As such, we need some way
> to communicate to the unwinder to do that.
>
> In a discussion on llvm-dev [1], it was decided the best way to go
> forward with this would be to add a new character ('G' for taG, as the
> MTE instructions stg etc.) to the eh_frame augmentation string, and
> then handle that in libunwind by clearing the tags of the respective
> frame.
>
> How does that sound? Would that be a good course of action for GCC as well?
>
> Thanks,
> Florian
>
> [1]: https://lists.llvm.org/pipermail/llvm-dev/2020-May/141345.html
Hi Florian,
This is something that needs to be specified in the ABI, not just agreed
between a couple of compilers. So while the community input is helpful,
it isn't enough.
The correct place to do this is in the ABI project here:
https://github.com/ARM-software/abi-aa
R.
next prev parent reply other threads:[~2022-06-06 11:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-03 23:52 Florian Mayer
2022-06-06 11:00 ` Richard Earnshaw [this message]
2022-06-06 14:15 ` Matthew Malcomson
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=00728f04-2b84-13a3-2ebb-34f5953d28a5@foss.arm.com \
--to=richard.earnshaw@foss.arm.com \
--cc=eugenis@google.com \
--cc=fmayer@google.com \
--cc=gcc@gcc.gnu.org \
--cc=maskray@google.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).