Mapping memory into process address space

Noah Zentzis nzentzis at pdx.edu
Wed Aug 20 05:59:16 CEST 2014


On 08/17/2014 12:55 AM, Adam Lackorzynski wrote:
> So now I'm not sure how you want to proceed. Are your programs special
> ones, i.e. that they are quite different from L4 programs or are they L4
> programs? I wondering where to do the paging, however, in any case it
> sounds to me like doing it in a different task would be good.
>
> To address your question:
> You map the pager to the task with the dst_task->map() call as shown
> above. The pager is probably a thread you implement, for doing your
> work. The order does not really matter because the thread only starts
> running until the run_thread call, i.e. it does not matter whether the
> pager cap (any cap) is mapped before or after it has been registered
> with the thread.

How would I configure the new task to use the same pager that the 
current task is? Looking at libloader, I'd think it would be something like:

task-map(L4Re::This_task, env->rm().fpage(), env->rm().snd_base());

but I'm not sure if I need to create a new region map or something like 
that. I think I've got memory mapping working, but the process dies with 
an unhandled read page fault.

- Noah Zentzis



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