From: Brian Gerst <bgerst@didntduck.org>
To: Alon Bar-Lev <alon.barlev@gmail.com>
Cc: "Jonathan M. McCune" <jonmccune@cmu.edu>,
linux-kernel@vger.kernel.org,
Arvind Seshadri <arvinds@cs.cmu.edu>, Bryan Parno <parno@cmu.edu>
Subject: Re: using segmentation in the kernel
Date: Tue, 11 Oct 2005 17:14:50 -0400 [thread overview]
Message-ID: <434C2B4A.7040309@didntduck.org> (raw)
In-Reply-To: <434C1F8E.6080405@gmail.com>
Alon Bar-Lev wrote:
> Brian Gerst wrote:
>
>> Jonathan M. McCune wrote:
>>
>>> Hello,
>>>
>> Why send the kernel back to the 2.0 days? There is no valid reason
>> for doing this with they way x86 segmentation works, which is why it
>> was done away with in 2.1.
>>
>
> But with segmentation you can set code to be read-only, disallow
> execution from stack, separate modules so that they will not affect
> kernel and more...
>
> The main problem with segmentation is that it is x86 specific...
Too much pain for for not enough gain. Segments are not fine-grained
enough to work well. Look at the PaX and execshield hacks for
userspace. You are far better off working at the page-table level (RO
and NX pages) which has the advantage of being portable.
--
Brian Gerst
next prev parent reply other threads:[~2005-10-11 21:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-11 20:15 using segmentation in the kernel Jonathan M. McCune
2005-10-11 20:36 ` Brian Gerst
2005-10-11 20:24 ` Alon Bar-Lev
2005-10-11 21:12 ` Al Viro
2005-10-11 21:14 ` Brian Gerst [this message]
2005-10-12 9:05 ` Arjan van de Ven
2005-10-12 16:07 ` Alan Cox
2005-10-12 15:44 ` Arjan van de Ven
2005-10-12 23:55 ` Jonathan M. McCune
2005-10-12 13:03 ` linux-os (Dick Johnson)
2005-10-13 8:51 ` Denis Vlasenko
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=434C2B4A.7040309@didntduck.org \
--to=bgerst@didntduck.org \
--cc=alon.barlev@gmail.com \
--cc=arvinds@cs.cmu.edu \
--cc=jonmccune@cmu.edu \
--cc=linux-kernel@vger.kernel.org \
--cc=parno@cmu.edu \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.