Re: [Qemu-devel] Getting current PGD on address@hidden

[Igor R]

>> On x86 one can get the current PGD from CR3. What's the right way to
>> do this on ARM?
>
> What's a PGD ?

Page global directory


> However just looking at base & mask is not necessarily
> correct -- depending on the configuration of the CPU we
> might be using translation table base control registers
> in a different format, in which case mask and base_mask
> are meaningless. (See the comment in vmsa_ttbcr_raw_write().)

Ok, thanks, I'll take a look at it.


>> But in the recent QEMU version c2_base0 field is absent. Instead,
>> there's ttbr0[] array. So should I just use ttbr0[current_el]?
>
> What are you trying to do inside QEMU with the page tables?

When debugging (via gdbstub), I would like to get the current process
id by a virtual address. When the virtual address is in the
user-space, the only way to find the current task_struct I can think
of is to iterate over all the task_struct's (assuming we know
task_init and the offsets of the relevant fields), and compare
task->mm->pgd against the current PGD.


Thanks!