From: Jamie Lokier <jamie@shareable.org>
To: Andi Kleen <ak@suse.de>
Cc: Linus Torvalds <torvalds@osdl.org>,
Nick Piggin <piggin@cyberone.com.au>,
Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, richard.brunner@amd.com
Subject: Re: [PATCH] Athlon/Opteron Prefetch Fix for 2.6.0test5 + numbers
Date: Thu, 18 Sep 2003 17:04:56 +0100 [thread overview]
Message-ID: <20030918160456.GC7548@mail.jlokier.co.uk> (raw)
In-Reply-To: <20030918153831.GA7548@mail.jlokier.co.uk>
Jamie Lokier wrote:
> > + /* Don't check for LDT code segments because they could have
> > + non zero bases. Better would be to add in the base in this case. */
> > + if (regs->xcs & (1<<2))
> > + return 0;
>
> It is possible to have a non-standard code segment in the GDT, too.
> Thus a better to check is "unlikely((regs->xcs & 0xffff) != __USER_CS)".
Ignore me here, I'm being dense - forgetting about __KERNEL_CS :)
My point is simply that non-zero base GDT segments are possible in
userspace, and whatever code you add later to add the base should
be aware of that.
-- Jamie
next prev parent reply other threads:[~2003-09-18 16:05 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-17 2:22 [PATCH] Athlon/Opteron Prefetch Fix for 2.6.0test5 + numbers Andi Kleen
2003-09-17 2:44 ` Andrew Morton
2003-09-17 3:25 ` Andi Kleen
2003-09-17 4:53 ` Nick Piggin
2003-09-17 5:08 ` Andrew Morton
2003-09-17 5:19 ` Nick Piggin
2003-09-17 7:15 ` Dave Hansen
2003-09-17 5:26 ` Andi Kleen
2003-09-17 5:44 ` Nick Piggin
2003-09-17 19:53 ` Linus Torvalds
2003-09-17 20:21 ` Andi Kleen
2003-09-17 20:50 ` Linus Torvalds
2003-09-17 21:12 ` Andi Kleen
2003-09-18 15:38 ` Jamie Lokier
2003-09-18 16:04 ` Jamie Lokier [this message]
2003-09-18 17:06 ` Andi Kleen
2003-09-18 19:48 ` Jamie Lokier
2003-09-19 6:55 ` Kai Henningsen
2003-09-19 10:02 ` Andreas Schwab
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