* Page table mapped and identity segments!
@ 2003-11-04 10:22 Ameya Mitragotri
2003-11-04 10:29 ` Keith Owens
2003-11-04 11:00 ` Christian Hildner
0 siblings, 2 replies; 3+ messages in thread
From: Ameya Mitragotri @ 2003-11-04 10:22 UTC (permalink / raw)
To: linux-ia64
Hello,
I am refering to David's and Stephanes's book on the IA64 linux kernel.
From my understanding,
1) I can see that the PAGE_OFFSET which designates the start of
the identity mapped segment starts at 0xe000000000000000 (region 7).
2) This region has the linux kernel text/data/stack segments.
Now after compiling the linux-2.6.0-test5 on an itanium-2 machine,
the System.map generated contains addresses only starting with
0xa0000..which means all these lie in the page table mapped segments
(region 5).
Why is this happening?
Apologies if this is too trivial to be asked.
Thanks
Ameya
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Page table mapped and identity segments!
2003-11-04 10:22 Page table mapped and identity segments! Ameya Mitragotri
@ 2003-11-04 10:29 ` Keith Owens
2003-11-04 11:00 ` Christian Hildner
1 sibling, 0 replies; 3+ messages in thread
From: Keith Owens @ 2003-11-04 10:29 UTC (permalink / raw)
To: linux-ia64
On Tue, 4 Nov 2003 15:40:06 +0530,
"Ameya Mitragotri" <ameya.mitragotri@wipro.com> wrote:
>I am refering to David's and Stephanes's book on the IA64 linux kernel.
From my understanding,
>
>1) I can see that the PAGE_OFFSET which designates the start of
>the identity mapped segment starts at 0xe000000000000000 (region 7).
>
>2) This region has the linux kernel text/data/stack segments.
>
>Now after compiling the linux-2.6.0-test5 on an itanium-2 machine,
>the System.map generated contains addresses only starting with
>0xa0000..which means all these lie in the page table mapped segments
>(region 5).
The book refers to the 2.4 and earlier kernels. In 2.6 kernels the
kernel code and data lives in region 5, not 7.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Page table mapped and identity segments!
2003-11-04 10:22 Page table mapped and identity segments! Ameya Mitragotri
2003-11-04 10:29 ` Keith Owens
@ 2003-11-04 11:00 ` Christian Hildner
1 sibling, 0 replies; 3+ messages in thread
From: Christian Hildner @ 2003-11-04 11:00 UTC (permalink / raw)
To: linux-ia64
Ameya Mitragotri schrieb:
>Hello,
>I am refering to David's and Stephanes's book on the IA64 linux kernel.
From my understanding,
>
>1) I can see that the PAGE_OFFSET which designates the start of
>the identity mapped segment starts at 0xe000000000000000 (region 7).
>
>2) This region has the linux kernel text/data/stack segments.
>
>Now after compiling the linux-2.6.0-test5 on an itanium-2 machine,
>the System.map generated contains addresses only starting with
>0xa0000..which means all these lie in the page table mapped segments
>(region 5).
>
>Why is this happening?
>
Kernel mapping has changed in the 2.6 kernel. The kernel is now
relocatable (needed for new hardware). Because of that it was decided to
move the kernel outside the identity mapped region. But the virtual to
physical mappings are nevertheless done with the old mechanism of pinned
large 64M pages for text and data. See head.S where these mappings are done.
Christian
>
>
>Apologies if this is too trivial to be asked.
>
>Thanks
>Ameya
>
>-
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>
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2003-11-04 10:22 Page table mapped and identity segments! Ameya Mitragotri
2003-11-04 10:29 ` Keith Owens
2003-11-04 11:00 ` Christian Hildner
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