On Mon, Jun 28, 2010 at 6:34 AM, sam shepperd <samshepperd@xxxxxxxxx> wrote:
On Mon, Jun 28, 2010 at 12:47 AM, Venkatram TummalaThis is what I need (pgd_offset_k), thank you!!
<venkatram867@xxxxxxxxx> wrote:
> On Sun, Jun 27, 2010 at 10:05 PM, Mulyadi Santosa
> <mulyadi.santosa@xxxxxxxxx> wrote:
>>
>> On Mon, Jun 28, 2010 at 09:54, sam shepperd <samshepperd@xxxxxxxxx> wrote:
>> > Kindly thanks - that helps. However the virtual address of the kernel
>> > symbol I am looking up in memory is not within current->mm.
>
> I see. I think i know what you mean . Your symbol is in kernel address
> space. I think the mm_struct object you are looking for is init_mm . If so,
> in the above code I wrote, use pgd_offset_k(addr) instead of pgd_offset(mm,
> addr). I think that is what you are looking for. Correct me if I
> misunderstood you.
>
> Venkatram Tummala
On new kernels init_mm is not exported however. Is there a
replacement I can use from a module? mm_struct->mmlist is no longer a
list of all mm's (only swapped mm's). I would like a way to walk from
current->mm to init_mm. Google seems to indicate rmap can do this but
I cannot find any code.
Glad that pgd_offset_k(..) worked. I dont think you can walk through the mm_struct objects. Ideally, there should be no reason for anybody to be accessing all mm_structs. All the kernel should care about is current->mm & init_mm. You should not be poking into somebody's else address space. I understand that you want to do this because init_mm is no longer exported by the kernel.
As far as i know, the only way to access init_mm from a kernel module is to do a EXPORT_SYMBOL(..) in the kernel & compile it.
As a workaround, you can walkthrough the task_struct objects, and you can get the mm_struct object from the task_struct object. Having said that, its a pretty bad workaround & certainly it will not be accepted by kernel community if at all you care anything about it.
Venkatram Tummala
As far as i know, the only way to access init_mm from a kernel module is to do a EXPORT_SYMBOL(..) in the kernel & compile it.
As a workaround, you can walkthrough the task_struct objects, and you can get the mm_struct object from the task_struct object. Having said that, its a pretty bad workaround & certainly it will not be accepted by kernel community if at all you care anything about it.
Venkatram Tummala
