PFN to virtual address for identity mapped segment

PFN to virtual address for identity mapped segment

[Arvind Kandhare]

Hi,
We are working on porting LKCD (Linux Kernel Crash Dump) to the ia64 platform.
The normal dumping procedure goes through all the Physical Page Frame Numbers,
finds out the corresponding virtual addresses for all of them and dumps the data.

We are facing difficulty in finding out corresponding virtual address if
it is in the identity mapped region (region 7). The macro pfn_to_page does not seem to return
proper page structure for this region although region 7 does seem to have corresponding page
table entries (in the PTE table).
But it does not have entries for memory for the pages which are allocated by the alloc_pages call.

Please let us know whether our understanding is correct. Any more light on this matter will be really helpful.

Thanks and regards,
Arvind

Re: PFN to virtual address for identity mapped segment

[Keith Owens]

On Sun, 23 Nov 2003 17:56:10 +0530, 
Arvind Kandhare <arvind.kan@wipro.com> wrote:
>We are working on porting LKCD (Linux Kernel Crash Dump) to the ia64 platform.

LKCD already works on ia64, SGI use it all the time.  Inside SGI, I
(kaos a.t. sgi.com) maintain the kernel patches for LKCD, Tom Morano
(tjm a.t. sgi.com) maintains the user space code (lcrash).  Tom has
made a lot of changes to lcrash to make it support discontiguous memory
and other ia64 peculiarities.

RE: PFN to virtual address for identity mapped segment

[Abbott, Phillip]

How about porting mcore to ia-64 ? it seems to work nicely on ia-32, and
is quicker reaping dumps ...

-----Original Message-----
From: linux-ia64-owner@vger.kernel.org
[mailto:linux-ia64-owner@vger.kernel.org]On Behalf Of Keith Owens
Sent: 24 November 2003 00:28
To: arvind.kan@wipro.com
Cc: linux-ia64@vger.kernel.org
Subject: Re: PFN to virtual address for identity mapped segment 


On Sun, 23 Nov 2003 17:56:10 +0530, 
Arvind Kandhare <arvind.kan@wipro.com> wrote:
>We are working on porting LKCD (Linux Kernel Crash Dump) to the ia64 platform.

LKCD already works on ia64, SGI use it all the time.  Inside SGI, I
(kaos a.t. sgi.com) maintain the kernel patches for LKCD, Tom Morano
(tjm a.t. sgi.com) maintains the user space code (lcrash).  Tom has
made a lot of changes to lcrash to make it support discontiguous memory
and other ia64 peculiarities.

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