linux-kernel - RE: [PATCH] x86: clear XD_DISABLED flag on Intel to regain NX

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <SNT125-W601D37A89A8CBFFDFFF40EC3C00@phx.gbl>
Date:	Thu, 17 Jun 2010 19:07:31 -0700
From:	Yuhong Bao <yuhongbao_386@...mail.com>
To:	<hpa@...or.com>, <kees.cook@...onical.com>
CC:	<x86@...nel.org>, <linux-kernel@...r.kernel.org>,
	<tglx@...utronix.de>, <mingo@...hat.com>, <tabbott@...lice.com>,
	<sam@...nborg.org>, <heukelum@...tmail.fm>
Subject: RE: [PATCH] x86: clear XD_DISABLED flag on Intel to regain NX

> a) Not all Intel CPUs with extended CPUID levels have
> MSR_IA32_MISC_ENABLE bit 34. Since we can't take traps here we would
> have to know positively that we aren't going to trip on anything.
It won't as these older Intel CPUs are always going to read this bit as zero, and even if no checking for this is include all the wrmsr would do is write the same value back, which won't cause a trap.

Yuhong Bao

_________________________________________________________________
Hotmail has tools for the New Busy. Search, chat and e-mail from your inbox.
http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_1--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/