From: ebiederm@xmission.com (Eric W. Biederman)
To: Jiri Olsa <jolsa@redhat.com>
Cc: tglx@linutronix.de, mingo@redhat.com, x86@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86_64: disable identity mappings statically
Date: Fri, 11 Feb 2011 08:46:41 -0800 [thread overview]
Message-ID: <m14o8a34em.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <1297432830-3912-1-git-send-email-jolsa@redhat.com> (Jiri Olsa's message of "Fri, 11 Feb 2011 15:00:30 +0100")
Jiri Olsa <jolsa@redhat.com> writes:
> hi,
>
> while browsing the page table setup code, I noticed the x86_64 head
> code might not need the identity mappings at all.
> It seems it's ok to switch it off completely from the begining,
> unless I'm missing something.
Have you tested it?
I expect you will find that we need the identity mapping because
before we load this page table we are running with virt==phys
and we need the identity mapping retained in the new page table
so we can get to the instruction after movq %rax, %cr0.
Eric
next prev parent reply other threads:[~2011-02-11 16:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-11 14:00 [PATCH] x86_64: disable identity mappings statically Jiri Olsa
2011-02-11 16:46 ` Eric W. Biederman [this message]
2011-02-11 17:07 ` Jiri Olsa
2011-02-11 17:35 ` Cyrill Gorcunov
2011-02-11 17:59 ` Brian Gerst
2011-02-11 19:13 ` Jiri Olsa
2011-02-11 20:19 ` Brian Gerst
2011-02-11 20:40 ` Jiri Olsa
2011-02-11 21:59 ` Brian Gerst
2011-02-12 8:57 ` Jiri Olsa
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