check if a kernel page is read-only

I think I can do that by getting the related pte of a virtuak kaddr,
starting with

 pgd_offset_k <http://lxr.free-electrons.com/ident?i=pgd_offset_k>(address
<http://lxr.free-electrons.com/ident?i=address>)

, or directly with

pte_t <http://lxr.free-electrons.com/ident?i=pte_t> *lookup_address
<http://lxr.free-electrons.com/ident?i=lookup_address>(unsigned long
address <http://lxr.free-electrons.com/ident?i=address>, unsigned int
*level <http://lxr.free-electrons.com/ident?i=level>);

  And then I can checks the flags of this pte.





2016-09-05 12:59 GMT+02:00 Oscar Salvador [off-list ref]:

Hi all,

I'm writing a module to read/write kernel memory, and for this I'd like to
check if a page is marked as read-only, so we don't have the right to write
there (kernel code for instance).

I though about the flags field from "struct page {}", but from the name I
can't see any useful flag to check this.

The only flag I saw is different between kernel code and module code is
that kernel code has the flag "reserved" enabled, so it's not swapped.

Could someone provide me a hint about that?

Thank you very much

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