How to avoid kernel Oops 0x81F in function do_alignment() ?

[subin gangadharan]

Hi,


>    2. how can i change the page permisson before write back instruction of
> user mode application?
>       for example, find out the page tables of current application, find out
> the pte which represents
> the instruction that generate data abort, then modify pte, write back
> instruction, restore pte, done.
>     how to do these?

I think you can get the pgd of this process by current->mm->pgd and
pgd_offset macro to ge the pgd entry for that address. There are
macros available for accessing pmd and pte too. For example
pte_offset_map for pte and a locking version for the same is also
there. I don't have any hands on experience on this,  so our kernel
experts can comment on this more.

And one more thing, if you can look at the function handle_mm_fault
(mm/memory.c), there are plenty of refererces for accesing these page
table entries.

With Regards,
Subin K G



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-- 
With Regards
Subin Gangadharan

I am not afraid and I am also not afraid of being afraid.