Re: l4/sys/syscalls.h: No such file or directory

Valentin Hauner <[email protected]> Tue, 02 Sep 2014 11:19:35 +0200

Newsgroups	gmane.comp.micro-kernel.l4.devel
Message-ID	<[email protected]>

Hi,

On 09/02/2014 12:27 AM, Adam Lackorzynski wrote:
> Most use the C++ interface, so looking for 'create_task' is better.
> Why not use ned for creating tasks?
My whole EDF library is written in C now, so switching to C++ or Lua
makes it very uncomfortable for me.


On 09/02/2014 12:27 AM, Adam Lackorzynski wrote:
> 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).
Thanks, that part is working now. The new tasks are created properly and
displayed as 'ready' in the JDB thread list.

But there's another problem: Using the region mapper of the current task
does not work for the newly created tasks, of course.
I've attached a small example that illustrates the problem (task
creation: lines 19-25, setting pager and exception handler: lines
40-48). I've tried to make it as small as possible for your convenience.

How can I create a dedicated region mapper for each of the new tasks? Or
is it better to just map the old region mapper to the new tasks? I've found
> l4_task_map(task_cap, L4RE_THIS_TASK_CAP, ... )
but I didn't come along with the third and fourth parameter.

Best regards,
Valentin

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l4_create_task_for_each_thread.c (text/x-csrc, 2.4 KB)

#define THREAD_MAX_NUM 20

typedef struct Edf_thread
{
  unsigned     dl;       // Deadline
  void        *func;     // EIP
  l4_cap_idx_t cap;      // L4 Capability
} Edf_thread;

Edf_thread     thread[THREAD_MAX_NUM];
unsigned char *thread_stack[THREAD_MAX_NUM];

unsigned       count = 0;

int create_l4_thread(Edf_thread *_thread)
{
  l4_msgtag_t tag;

  // Create a new task for each thread
  l4_cap_idx_t task_cap = l4re_util_cap_alloc();
  if (l4_is_invalid_cap(task_cap))
    return -1;
  l4_fpage_t task_fpage = l4_fpage(l4re_env()->first_free_utcb, 12, L4_CAP_FPAGE_RW);
  l4_factory_create_task(l4re_env()->factory, task_cap, task_fpage);
  //

  _thread->cap = l4re_util_cap_alloc();
  thread[count] = *_thread;
  thread_stack[count] = malloc(8 << 10);

  if (l4_is_invalid_cap(_thread->cap))
    return -1;

  tag = l4_factory_create_thread(l4re_env()->factory, _thread->cap);
  if (l4_error(tag))
    return -1;

  l4_thread_control_start();

  /*
   * Of course, using the region mapper and exception handler of the current task for the newly created task fails.
   * I'm getting the following kernel output:
   * > KERNEL: Warning: CPU0: Pager of 26 is invalid (pfa=010002c0, errorcode=00000004) to 3 (pc=10002c0)
   * But how can I create a new region mapper?
   * Or is it better to just map the old one to the new task? l4_task_map(task_cap, L4RE_THIS_TASK_CAP, ... ?)
   */
  l4_thread_control_pager(l4re_env()->rm);       // fails
  l4_thread_control_exc_handler(l4re_env()->rm); // fails

  l4_thread_control_bind((l4_utcb_t *)l4re_env()->first_free_utcb,
                          task_cap);
  tag = l4_thread_control_commit(_thread->cap);
  if (l4_error(tag))
    return -2;

  tag = l4_thread_ex_regs(_thread->cap,
                          (l4_umword_t)_thread->func,
                          (l4_umword_t)(thread_stack[count] + sizeof(thread_stack[count])), 0);
  if (l4_error(tag))
    return -3;

  // Pass the deadline of the thread to the L4 system
  l4_sched_param_t sp = l4_sched_param_by_type(Deadline, thread[count].dl, 0);
  // Let the L4 system tell the kernel to enqueue the thread in its (deadline-based) ready queue
  tag = l4_scheduler_run_thread(l4re_env()->scheduler, thread[count].cap, &sp);
  if (l4_error(tag))
    return -4;

  // Shift first_free_utcb for further threads
  l4re_env()->first_free_utcb = (l4_addr_t)l4re_env()->first_free_utcb + L4_UTCB_OFFSET;

  return count++;
}