2008-10-17 07:07:27

by Peter Teoh

[permalink] [raw]
Subject: How to get the PTE pointer for a linear address?

If I allocate kernel memory via alloc_page(GFP_KERNEL), and convert
that struct page pointer to linear address via page_address(), how do
I derive the PTE pointer of that page?

Following the source code, I did the following:

pgd_t *pgd = pgd_offset_k(address);

if (pgd_none(*pgd)) {
printk("no pgd ");
return 0;
}
pud = pud_offset(pgd, address);
if (pud_none(*pud)) {
printk("no pud ");
return 0;
}
pmd = pmd_offset(pud, address);
if (pmd_none(*pmd)) {
printk("no pmd ");
return 0;
}

pte = pte_offset_map(pmd, address);

===============> and in between here, the PTE pointer is returned
(from pte_offset_map())? And so the PTE structure (pte_t) should be
*pte?

pte_unmap(pte);

I suspect something is not right?

Thanks.
--
Regards,
Peter Teoh