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

[弋天 卜]

hi subin:

Thanks,I have solved this issue, the 
Method looks the same as you mentioned. 



在 2012-3-14，11:12，"subin gangadharan" <subingangadharan at gmail.com> 写道：

> 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.
> 
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