Why is a PA converted to a VA in pmd_page?

"Kirk True" <ktrue@movaris.com> · Thu, 10 Jul 2003 12:37:37 -0700

Hi all,

In <asm>/pgtable.h, it defines the following:

    323 #define pmd_page(pmd) \
    324 ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))

Why does it convert the physical address provided by pmd_val to a virtual
one? The addresses returned from pgd_offset and pmd_offset represent a
physical address, correct? Then why the switch to a virtual address for the
pte_offset?

Aren't these methods called from the kernel in the physical address space
rather than the linear/virtual address space?

I'm confused, please help ;)

Thanks,
Kirk
___________________________________

Kirk True
Movaris Process Server Project Lead
Movaris
(408) 540-1405
___________________________________

--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive:       http://mail.nl.linux.org/kernelnewbies/
FAQ:           http://kernelnewbies.org/faq/