Re: Calculating kernel logical address ..

From: Manfred Spraul (manfred@colorfullife.com)
Date: Fri Sep 06 2002 - 10:44:29 EST

> adr = user_address;
> pgd_offset(current->mm, adr);
>
> if (!pgd_none(*pgd)) {
> pmd = pmd_offset(pgd, adr);
> if (!pmd_none(*pmd)) {
> ptep = pte_offset(pmd, adr);
> pte = *ptep;
> if(pte_present(pte)) {
> kaddr = (unsigned long) page_address(pte_page(pte));
> kaddr |= (adr & (PAGE_SIZE - 1));
> }
> }
> }
>
> Will this code always give me correct kernel logical address?
>
What about

        kmalloc_buffer+(user_address-vma->vm_start)

?
A driver should avoid accessing the page tables. 

--
	Manfred

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This archive was generated by hypermail 2b29 : Sat Sep 07 2002 - 22:00:29 EST