Rodolfo wrote:
> Gilles Chanteperdrix wrote:
>
>>Rodolfo wrote:
>>
>>
>>>Hi,
>>>I am totally new to Xenomai and have no experience with RTAI. I'm trying
>>>to load a kernel module that uses the native API for testing, but I get
>>>the following segmentation fault. Can anyone help me out??
>>>
>>
>>Please post here the sources of your module.
>>
>>
>
>
>
> here's the source of the testing module.
>
> #include <linux/module.h>
> #include <linux/kernel.h>
> #include <linux/proc_fs.h>
> #include <native/task.h>
> #include <native/types.h>
> #include <native/timer.h>
> #include <rtdm/rtdm_driver.h>
> #include <nucleus/pod.h>
>
> MODULE_LICENSE("GPL");
> MODULE_DESCRIPTION("Hello World Xenomai Application");
>
> /************************* Global Variables ******************************/
>
> RT_TASK thread;
> RTIME timer_period_ns;
> RTIME task_period_ns;
> RTIME expected;
> int timer_period_counts;
> unsigned long overrun; // rt_task_wait_period() writes here overrun
> count.0 if everything OK
>
> /************************* Periodic realtime thread **********************/
>
> void fun(int dummy) {
> int count = 0;
> while(1) {
> ++count;
> rt_task_wait_period(&overrun);
Before calling rt_task_wait_period, you should have called
rt_task_set_periodic. Here, rt_task_wait_period will continuously return
-EWOULDBLOCK and you will get a hard lockup.
> if ((count%100)==0) {
> rtdm_printk("Periode %d ist abgelaufen\n",count);
> }
> }
> }
>
> /************************* Initialisation *******************************/
>
> static int hello_init(void)
> {
> //testing rt_task_create(...);
> int count = 0;
> printk("task create");
> rt_task_create(&thread,"fun_task",3000,1,0);
> printk("created..");
> printk("task start");
> rt_task_start(&thread,fun,0);
At this point you do not know if rt_task_create succeeded, since you did
not check its return value.
> printk("started........");
>
>
>
> //timer_period_ns = 10000000;/*10ms*/
> /*timer_period_counts = start_rt_timer(nano2count(timer_period_ns));*/
>
> //timer_period_counts=rt_timer_set_mode(rt_timer_ns2tsc(timer_period_ns));
Setting the timer to periodic mode results in a lower timer resolution.
Aperiodic mode, the default is usually fine.
> /* Calculate the start time for the task. */
> /* We set this to "now plus 10 periods" */
> //expected = xnpod_get_time() + 10 * timer_period_counts;
xnpod_get_time is not part of the native API, what you want is
rt_timer_read.
>
> /* Task period initialization */
> //task_period_ns =50000000;/*5ms*/
> /*rt_task_make_periodic(&thread, expected,
> nano2count(task_period_ns));*/
> //rt_task_set_periodic(&thread, expected,
> rt_timer_ns2tsc(task_period_ns));
> return 0;
> }
>
> /************************* Cleanup *********************************/
>
> static void hello_exit(void)
> {
> /*stop_rt_timer();*/
>
> /* Now delete our task */
> // rt_task_delete(&thread);
> }
>
> module_init(hello_init);
> module_exit(hello_exit);
Why do you want to use Xenomai in kernel-space ? Since, as you said it,
you are a beginner, you should use Xenomai in user-space. There, gdb
will help you debug your segmentation faults.
--
Gilles Chanteperdrix
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