On Mon Sep 01, 2014 at 18:31:40 +0200, Valentin Hauner wrote:
On 09/01/2014 12:02 AM, Adam Lackorzynski wrote: I'm currently struggling with creating a new task. I guess, according to the initial post of this mailing list thread, using the following interface is deprecated? https://os.inf.tu-dresden.de/L4/l4libman/l4_task_new.html
It belongs to a previous and now incompatible version of L4. It won't work anymore.
So I've found l4_factory_create_task in factory.h. Unfortunately, there seems to be no example in ./l4/pkg how to use it.
Most use the C++ interface, so looking for 'create_task' is better.
My first try is the following:
l4_cap_idx_t task_cap = l4re_util_cap_alloc(); l4_fpage_t task_fpage = l4_fpage(l4re_env()->first_free_utcb, 1024,
L4_CAP_FPAGE_RW);
l4_factory_create_task(l4re_env()->factory, task_cap, task_fpage); // Create thread, start thread control sequence ... l4_thread_control_bind((l4_utcb_t *)l4re_env()->first_free_utcb, task_cap); // Commit & shift first_free_utcb ...
But when executing the example, the states of all threads created are set to 'dead'. I'm not sure about using first_free_utcb as start address for the flex-page as it is used as a offset for threads' UTCBs normally.
When creating a new task you're free to put the UTCB area anywhere in the task's address space. Also, the size argument of l4_fpage is the size in log2, so maybe 12 is a good number (the minimum because it's a page). Of course you can use the same address range for the new task, so using l4re_env()->first_free_utcb is ok (lower bits are truncated by l4_fpage, so just using it is ok).
Can you give a small working example for creating new tasks? Basically, I want to create a new task for each thread demanded by my end users. So the number of tasks and threads to create is variable.
examples/sys/vcpu/vcpu.cc creates a task, however does not directly put a thread in there, you have to adapt that part a bit. Why not use ned for creating tasks?
Adam