public inbox for libc-ports@sourceware.org
 help / color / mirror / Atom feed
From: Will Newton <will.newton@linaro.org>
To: Roland McGrath <roland@hack.frob.com>
Cc: libc-ports@sourceware.org
Subject: Re: ARM per-thread stack protector
Date: Mon, 22 Jul 2013 09:15:00 -0000	[thread overview]
Message-ID: <CANu=DmhQXD2NO4a2ACned-s08m6jzjJaQ2vPO4FppdDejsjiBg@mail.gmail.com> (raw)
In-Reply-To: <20130719214113.EDAD02C0A1@topped-with-meat.com>

On 19 July 2013 22:41, Roland McGrath <roland@hack.frob.com> wrote:

Hi Roland,

> No machine has a per-thread canary value.  Using one would break
> user-implemented stack-switching schemes.
>
> Some machines store the global canary value in every thread's TCB for the
> sole reason that it's cheaper to access a field in the TCB than to access a
> global variable.  I don't think that's the case on ARM.

Thanks for the clarification. So the two methods are functionally identical?

I looked at this problem initially after reading Carlos's mail to the
fedora devel list:

http://www.mail-archive.com/devel@lists.fedoraproject.org/msg62354.html

From what I understand then all that is missing on ARM from that list
is pointer mangling support?

Thanks,

--
Will Newton
Toolchain Working Group, Linaro

  reply	other threads:[~2013-07-22  9:15 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-19 16:34 Will Newton
2013-07-19 21:41 ` Roland McGrath
2013-07-22  9:15   ` Will Newton [this message]
2013-07-22 22:01     ` Roland McGrath

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='CANu=DmhQXD2NO4a2ACned-s08m6jzjJaQ2vPO4FppdDejsjiBg@mail.gmail.com' \
    --to=will.newton@linaro.org \
    --cc=libc-ports@sourceware.org \
    --cc=roland@hack.frob.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).