Re: pte_page

I am doing a DMA from a card to system memory. The system memory "physical
address" is '0x104000'. I am doing this on x86 with kernel version 2.4.2.
Can this address be the address of a user space buffer?

Regards,
Daljeet.

|--------+----------------------->
|        |          Ingo Molnar  |
|        |          <mingo@elte.h|
|        |          u>           |
|        |                       |
|        |          05/30/01     |
|        |          11:09 PM     |
|        |          Please       |
|        |          respond to   |
|        |          mingo        |
|        |                       |
|--------+----------------------->
  >--------------------------------------------------------|
  |                                                        |
  |       To:     Pete Wyckoff <[e-mail]>                |
  |       cc:     Daljeet Maini/India/IBM@IBMIN,           |
  |       [e-mail]                     |
  |       Subject:     Re: pte_page                        |
  >--------------------------------------------------------|

On Wed, 30 May 2001, Pete Wyckoff wrote:

> > __pa(page_address(pte_page(pte))) is the address you want. [or
> > pte_val(*pte) & (PAGE_SIZE-1) on x86 but this is platform-dependent.]
>
> Does this work on x86 non-kmapped highmem user pages too?  (i.e. is
> page->virtual valid for every potential user page.)

you are right, the highmem-compatible solution is to use page-mem_map as
the physical page index.

     Ingo