Date: Mon, 3 Nov 2003 16:41:16 -0800
From: "David S. Miller" <davem@redhat.com>
To: davidm@hpl.hp.com
Cc: davidm@napali.hpl.hp.com, jes@wildopensource.com,
       Jamie.Wellnitz@emulex.com, linux-kernel@vger.kernel.org
Subject: Re: virt_to_page/pci_map_page vs. pci_map_single
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On Mon, 3 Nov 2003 14:02:57 -0800
David Mosberger <davidm@napali.hpl.hp.com> wrote:

> >>>>> On 03 Nov 2003 09:17:59 -0500, Jes Sorensen <jes@wildopensource.com> said:
> 
>   Jes> Hmmm, my brain has gotten ia64ified ;-) It's basically the normal
>   Jes> mappings of the kernel, ie. the kernel text/data/bss segments as well
>   Jes> as anything you do not get back as a dynamic mapping such as
>   Jes> ioremap/vmalloc/kmap.
> 
> I don't think it's safe to use virt_to_page() on static kernel
> addresses (text, data, and bss).  For example, ia64 linux nowadays
> uses a virtual mapping for the static kernel memory, so it's not part
> of the identity-mapped segment.

That's correct and it'll break on sparc64 for similar reasons.

It's also not safe to do virt_to_page() on kernel stack addresses
either.
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