From: Andy Lutomirski <luto@amacapital.net>
To: Alexander Kuleshov <alex0xax@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: x86_64: Question about fixmaps
Date: Tue, 14 Apr 2015 17:28:46 -0700 [thread overview]
Message-ID: <552DB0BE.5020305@amacapital.net> (raw)
In-Reply-To: <CAFkLPWHg-AO2x-kFfHaw7ZP=w_Lq+pUST3a0Nm9o0G3eQWUk=w@mail.gmail.com>
On 04/14/2015 06:16 AM, Alexander Kuleshov wrote:
> Hello All,
>
> I'm reading x86_64 source code and trying to understand where are
> fixmaps space in the virtual memory space. If I understand correctly
> (but i'm really not sure about it), fixmap space is after vsyscall
> space. As Documentation/x86/x86_64/mm.txt says vsyscall virtual space
> is:
>
> ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls
>
> With 'earlyprintk' i got FIXADDR_START and FIXADDR_TOP and they are:
>
> FIXADDR_START - 0xffffffffff779000L
> FIXADDR_TOP - 0xffffffffff7ff000L
>
> with these addressess FIXADDR_START/FIXADDR_TOP overlap vsyscalls
> area. Is it correct case that fixmaps are in vsyscal virtual memory
> space or I'm wrong somewhere?
It's the other way around. vsyscalls are in the fixmap. I should fix
the docs.
--Andy
prev parent reply other threads:[~2015-04-15 0:28 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-14 13:16 Alexander Kuleshov
2015-04-15 0:28 ` Andy Lutomirski [this message]
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