Messages in this thread | | | From | mdaljeet@in ... | Date | Thu, 31 May 2001 15:27:38 +0530 | Subject | Re: pte_page |
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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 <pw@osc.edu> | | cc: Daljeet Maini/India/IBM@IBMIN, | | linux-kernel@vger.kernel.org | | 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
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