virt_to_page for userspace pointers (was: Reversing a memory mapping?)

[Nikolaus Rath <Nikolaus@rath.org>]

Nikolaus Rath <Nikolaus@rath.org> writes:
> Is there a way that my own kernel module can "reverse" this mmap call?
> I.e. given the userspace pointer, how do I get access to the physical
> location of the memory that has been mapped?

Ok, after some studying I think I can ask the question in a better way:

Is there an equivalent function to virt_to_page (and virt_to_phys) that
works with userspace pointers? Or do I have to manually walk through the
page tables? In the later case, are there any examples of this kind of
search that I could use as a basis?


Thanks,

   -Nikolaus

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