From: "H. Peter Anvin" <hpa@zytor.com>
To: Kees Cook <kees.cook@canonical.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, Pekka Enberg <penberg@cs.helsinki.fi>,
Jan Beulich <jbeulich@novell.com>,
Vegard Nossum <vegardno@ifi.uio.no>,
Yinghai Lu <yinghai@kernel.org>,
Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4] [x86] detect and report lack of NX protections
Date: Tue, 10 Nov 2009 12:25:39 -0800 [thread overview]
Message-ID: <4AF9CC43.50103@zytor.com> (raw)
In-Reply-To: <20091110194304.GW5129@outflux.net>
The more I stare at the underlying code, the more I'm convinced that the
fundamental problem is that the underlying code is insane, with multiple
levels of detection for what amounts to cpu_has_nx, each effectively
checking what the previous code has done.
check_efer(), for example, screws with EFER, but EFER is simply set in
head_64.S from CPUID (unless Xen does something insane -- but if so, Xen
should clear X86_FEATURE_NX instead.)
The 32-bit startup code also sets NX, but yet on 32 bits we wiggle EFER
as if it had never been. This code is screaming for cleanup and
unification.
-hpa
next prev parent reply other threads:[~2009-11-10 20:29 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-19 18:42 [PATCH] [x86] detect and report lack of NX protections Kees Cook
2009-10-19 23:43 ` Arjan van de Ven
2009-10-20 2:04 ` [PATCH v2] " Kees Cook
2009-10-20 2:18 ` H. Peter Anvin
2009-10-20 4:44 ` Kees Cook
2009-10-20 4:55 ` [PATCH v3] " Kees Cook
2009-11-09 22:10 ` [PATCH v4] " Kees Cook
2009-11-09 23:16 ` H. Peter Anvin
2009-11-10 15:49 ` Kees Cook
2009-11-10 16:47 ` H. Peter Anvin
2009-11-10 16:57 ` Kees Cook
2009-11-10 17:12 ` H. Peter Anvin
2009-11-10 17:46 ` Kees Cook
2009-11-10 18:53 ` H. Peter Anvin
2009-11-10 19:43 ` Kees Cook
2009-11-10 19:59 ` H. Peter Anvin
2009-11-10 20:55 ` Kees Cook
2009-11-10 21:22 ` H. Peter Anvin
2009-11-10 22:15 ` Kees Cook
2009-11-10 22:25 ` H. Peter Anvin
2009-11-12 18:01 ` Yuhong Bao
2009-11-10 20:25 ` H. Peter Anvin [this message]
2009-11-10 16:55 ` [PATCH v5] " Kees Cook
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=4AF9CC43.50103@zytor.com \
--to=hpa@zytor.com \
--cc=arjan@infradead.org \
--cc=jbeulich@novell.com \
--cc=jeremy.fitzhardinge@citrix.com \
--cc=kees.cook@canonical.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=penberg@cs.helsinki.fi \
--cc=tglx@linutronix.de \
--cc=vegardno@ifi.uio.no \
--cc=x86@kernel.org \
--cc=yinghai@kernel.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
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.