Re: [Xenomai-help] rtdm_event_timedwait hang-up - SOLVED

["Petr Cervenka" <grugh@domain.hid>]

The problem was in my calling "RT" task. I forgot to switch the new created task to PRIMARY MODE, because I didn't know it's neccessary. I still have same problems with porting the driver, but I think I can handle them myself.
Thanks for your help.
Petr Cervenka

>  Petr Cervenka wrote:
> > I' tried to create  user realtime task, and after all effort (and
> > many related partial problems solved) I still cannot do blocking
> > variant of rtdm_event_timedwait.
> > 1) How can I recognize, that the function is called within proper
> > context / ie. is there an rtdm equivalent to xnpod_unblockable_p?
> 
> First of all, there is the concept of the dual entry points, one for RT
> (xxx_rt), the other for non-RT (xxx_nrt). If your driver only registers
> a handler on xxx_rt, it will never get called in unblockable context. If
> it registers different functions on those entry points, it can easily
> tell the contexts apart.
> 
> Given that you have some significant amount of code to share between a
> RT and a non-RT invocation, you can register the same handler on both
> entry points. Then rtdm_in_rt_context() will tell you in which context
> you currently are.
> 
> > 2) Could be the problem elsewhere?
> 
> I prepared the attached patch that catches illegal service
> invocations. It will get checked in as soon as we decided how to switch
> XENO_ASSERTs on. For now this is done via CONFIG_XENO_OPT_DEBUG. Feel
> free to apply it on your Xenomai code and check if it's useful. I tested
> it a bit, and it didn't break anything of RTDM in an obvious way. :)
> 
> > 3) My General Standards PCI-24DSI-12 card is not supported by comedi.
> > And I'm not familiar with it either. The original driver is not so
> > complicated and the port looked as easy work ;-) But waiting inside
> 
> I can understand that you do not want to complicate your job with comedi
> when there is no support for your hardware anyway.
> 
> > ioctl or read handler for an interrupt is critical for proper
> > functionality.
> 
> This must work. See the 16550A driver e.g., it has a similar design,
> specifically for handling RTSER_RTIOC_WAIT_EVENT.
> 
> > 4) I realized when I make a realtime task (prio 1 ~ lowest, I hope)
> > and in my main (nrt) task I call sleep(1), It will fall asleep
> > forever (or maybe to some signal).
> 
> Sounds like something is blocking the Linux timer. Did you accidentally
> register your driver on it? See /proc/interrupts for the timer IRQ
> counter, in contrast to /proc/xenomai/irq.
> 
> > 5) Is it possible to set some event or to send signal/message/...
> > from rt to nrt and back?
> 
> rt->nrt: rtdm_nrtsig_xxx
> nrt->rt: any blocking rtdm-IPC service (except for mutexes of course)
> can be signalled also from non-rt
> 
> > 6) Is there some easy-to-understand documentation? What I can or
> > cannot...?
> 
> Did you browse the API documentation of RTDM, maybe also had a look at
> the related RTDM-and-Applications.pdf (hmm, were does a user get this
> from? At least, it's in the SVN, but the homepage still requires an
> update...)? If yes, please let us know what remains unclear and what
> would be additionally desirable. A tour on RTDM, like Philippe already
> wrote for other subsystems, would be nice - it just takes someone to
> write it...
> 
> > Petr Cervenka
> > 
> 
> Jan
> 
> Index: include/rtdm/rtdm_driver.h
> ===================================================================
> --- include/rtdm/.svn/text-base/rtdm_driver.h.svn-base	2006-03-09
> 22:16:03.000000000 +0100
> +++ include/rtdm/rtdm_driver.h	2006-03-20 17:55:10.000000000 +0100
> @@ -38,6 +38,7 @@
>  #include <nucleus>
>  #include <nucleus>
>  #include <nucleus>
> +#include <nucleus>
>  #include <rtdm>
>  
>  
> @@ -890,6 +891,7 @@ static inline rtdm_task_t *rtdm_task_cur
>  
>  static inline int rtdm_task_wait_period(void)
>  {
> +    XENO_ASSERT(!xnpod_unblockable_p(), return -EPERM;);
>      return xnpod_wait_thread_period(NULL);
>  }
>  
> Index: include/nucleus/assert.h
> ===================================================================
> --- include/nucleus/.svn/text-base/assert.h.svn-base	2006-03-08
> 00:48:14.000000000 +0100
> +++ include/nucleus/assert.h	2006-03-20 20:04:10.000000000 +0100
> @@ -22,18 +22,14 @@
>  
>  #include <nucleus>
>  
> -#ifndef CONFIG_XENO_OPT_DEBUG_LEVEL
> -#define CONFIG_XENO_OPT_DEBUG_LEVEL  0
> -#endif
> -
> -#if CONFIG_XENO_OPT_DEBUG_LEVEL > 0
> +#if CONFIG_XENO_OPT_DEBUG
>  #define XENO_ASSERT(cond,action)  do { \
>  if (unlikely((cond) != 0)) \
>  	do { action; } while(0); \
>  } while(0)
> -#else  /* CONFIG_XENO_OPT_DEBUG_LEVEL == 0 */
> +#else  /* !CONFIG_XENO_OPT_DEBUG */
>  #define XENO_ASSERT(cond,action) do { } while(0)
> -#endif /* CONFIG_XENO_OPT_DEBUG_LEVEL > 0 */
> +#endif /* CONFIG_XENO_OPT_DEBUG */
>  
>  #define XENO_BUGON(cond)  \
>      XENO_ASSERT(cond,xnpod_fatal("assertion failed at
> %s:%d",__FILE__,__LINE__))
> Index: ksrc/skins/rtdm/drvlib.c
> ===================================================================
> --- ksrc/skins/rtdm/.svn/text-base/drvlib.c.svn-base	2006-03-13
> 23:13:19.000000000 +0100
> +++ ksrc/skins/rtdm/drvlib.c	2006-03-20 20:11:38.000000000 +0100
> @@ -279,6 +279,8 @@ void rtdm_task_join_nrt(rtdm_task_t *tas
>      spl_t s;
>  
>  
> +    XENO_ASSERT(xnpod_root_p(), return;);
> +
>      xnlock_get_irqsave(&nklock, s);
>  
>      while (!xnthread_test_flags(task, XNZOMBIE)) {
> @@ -305,6 +307,9 @@ EXPORT_SYMBOL(rtdm_task_join_nrt);
>   * - -EINTR is returned if calling task has been unblock by a signal or
>   * explicitely via rtdm_task_unblock().
>   *
> + * - -EPERM @e may be returned if an illegal invocation environment is
> + * detected.
> + *
>   * Environments:
>   *
>   * This service can be called from:
> @@ -319,6 +324,8 @@ int rtdm_task_sleep(uint64_t delay)
>      xnthread_t  *thread = xnpod_current_thread();
>  
>  
> +    XENO_ASSERT(!xnpod_unblockable_p(), return -EPERM;);
> +
>      xnpod_suspend_thread(thread, XNDELAY, xnpod_ns2ticks(delay), NULL);
>  
>      return xnthread_test_flags(thread, XNBREAK) ? -EINTR : 0;
> @@ -337,6 +344,9 @@ EXPORT_SYMBOL(rtdm_task_sleep);
>   * - -EINTR is returned if calling task has been unblock by a signal or
>   * explicitely via rtdm_task_unblock().
>   *
> + * - -EPERM @e may be returned if an illegal invocation environment is
> + * detected.
> + *
>   * Environments:
>   *
>   * This service can be called from:
> @@ -354,6 +364,8 @@ int rtdm_task_sleep_until(uint64_t wakeu
>      int         err = 0;
>  
>  
> +    XENO_ASSERT(!xnpod_unblockable_p(), return -EPERM;);
> +
>      xnlock_get_irqsave(&nklock, s);
>  
>      delay = xnpod_ns2ticks(wakeup_time) - xnpod_get_time();
> @@ -626,6 +638,9 @@ EXPORT_SYMBOL(rtdm_event_signal);
>   *
>   * - -EIDRM is returned if @a event has been destroyed.
>   *
> + * - -EPERM @e may be returned if an illegal invocation environment is
> + * detected.
> + *
>   * Environments:
>   *
>   * This service can be called from:
> @@ -641,6 +656,8 @@ int rtdm_event_wait(rtdm_event_t *event)
>      int     err = 0;
>  
>  
> +    XENO_ASSERT(!xnpod_unblockable_p(), return -EPERM;);
> +
>      xnlock_get_irqsave(&nklock, s);
>  
>      if (testbits(event->synch_base.status, SYNCH_DELETED))
> @@ -689,6 +706,9 @@ EXPORT_SYMBOL(rtdm_event_wait);
>   *
>   * - -EIDRM is returned if @a event has been destroyed.
>   *
> + * - -EPERM @e may be returned if an illegal invocation environment is
> + * detected.
> + *
>   * Environments:
>   *
>   * This service can be called from:
> @@ -706,6 +726,8 @@ int rtdm_event_timedwait(rtdm_event_t *e
>      int         err = 0;
>  
>  
> +    XENO_ASSERT(!xnpod_unblockable_p(), return -EPERM;);
> +
>      xnlock_get_irqsave(&nklock, s);
>  
>      if (unlikely(testbits(event->synch_base.status, SYNCH_DELETED)))
> @@ -810,6 +832,9 @@ void rtdm_sem_destroy(rtdm_sem_t *sem);
>   *
>   * - -EIDRM is returned if @a sem has been destroyed.
>   *
> + * - -EPERM @e may be returned if an illegal invocation environment is
> + * detected.
> + *
>   * Environments:
>   *
>   * This service can be called from:
> @@ -825,6 +850,8 @@ int rtdm_sem_down(rtdm_sem_t *sem)
>      int     err = 0;
>  
>  
> +    XENO_ASSERT(!xnpod_unblockable_p(), return -EPERM;);
> +
>      xnlock_get_irqsave(&nklock, s);
>  
>      if (testbits(sem->synch_base.status, SYNCH_DELETED))
> @@ -878,6 +905,9 @@ EXPORT_SYMBOL(rtdm_sem_down);
>   *
>   * - -EIDRM is returned if @a sem has been destroyed.
>   *
> + * - -EPERM @e may be returned if an illegal invocation environment is
> + * detected.
> + *
>   * Environments:
>   *
>   * This service can be called from:
> @@ -895,6 +925,8 @@ int rtdm_sem_timeddown(rtdm_sem_t *sem, 
>      int         err = 0;
>  
>  
> +    XENO_ASSERT(!xnpod_unblockable_p(), return -EPERM;);
> +
>      xnlock_get_irqsave(&nklock, s);
>  
>      if (testbits(sem->synch_base.status, SYNCH_DELETED))
> @@ -1035,6 +1067,9 @@ void rtdm_mutex_destroy(rtdm_mutex_t *mu
>   *
>   * - -EIDRM is returned if @a mutex has been destroyed.
>   *
> + * - -EPERM @e may be returned if an illegal invocation environment is
> + * detected.
> + *
>   * Environments:
>   *
>   * This service can be called from:
> @@ -1050,6 +1085,8 @@ int rtdm_mutex_lock(rtdm_mutex_t *mutex)
>      int     err = 0;
>  
>  
> +    XENO_ASSERT(!xnpod_unblockable_p(), return -EPERM;);
> +
>      xnlock_get_irqsave(&nklock, s);
>  
>      if (testbits(mutex->synch_base.status, SYNCH_DELETED))
> @@ -1097,6 +1134,9 @@ EXPORT_SYMBOL(rtdm_mutex_lock);
>   *
>   * - -EIDRM is returned if @a mutex has been destroyed.
>   *
> + * - -EPERM @e may be returned if an illegal invocation environment is
> + * detected.
> + *
>   * Environments:
>   *
>   * This service can be called from:
> @@ -1114,6 +1154,8 @@ int rtdm_mutex_timedlock(rtdm_mutex_t *m
>      int         err = 0;
>  
>  
> +    XENO_ASSERT(!xnpod_unblockable_p(), return -EPERM;);
> +
>      xnlock_get_irqsave(&nklock, s);
>  
>      if (testbits(mutex->synch_base.status, SYNCH_DELETED))
> @@ -1179,6 +1221,8 @@ void rtdm_mutex_unlock(rtdm_mutex_t *mut
>      spl_t s;
>  
>  
> +    XENO_ASSERT(!xnpod_asynch_p(), return;);
> +
>      xnlock_get_irqsave(&nklock, s);
>  
>      __clear_bit(0, &mutex->locked);
> @@ -1426,6 +1470,9 @@ static struct file_operations rtdm_mmap_
>   * - -EAGAIN is returned if too much memory has been already locked by
> the
>   * user process.
>   *
> + * - -EPERM @e may be returned if an illegal invocation environment is
> + * detected.
> + *
>   * @note RTDM supports two models for unmapping the user memory range
> again.
>   * One is explicite unmapping via rtdm_munmap(), either performed when
> the
>   * user requests it via an IOCTL etc. or when the related device is
> closed.
> @@ -1457,6 +1504,9 @@ int rtdm_mmap_to_user(rtdm_user_info_t *
>      void                    *old_priv_data;
>      void                    *user_ptr;
>  
> +
> +    XENO_ASSERT(xnpod_root_p(), return -EPERM;);
> +
>      filp = filp_open("/dev/zero", O_RDWR, 0);
>      if (IS_ERR(filp))
>          return PTR_ERR(filp);
> @@ -1499,6 +1549,9 @@ EXPORT_SYMBOL(rtdm_mmap_to_user);
>   *
>   * - -EINVAL is returned if an invalid address or size was passed.
>   *
> + * - -EPERM @e may be returned if an illegal invocation environment is
> + * detected.
> + *
>   * Environments:
>   *
>   * This service can be called from:
> @@ -1512,6 +1565,9 @@ int rtdm_munmap(rtdm_user_info_t *user_i
>  {
>      int err;
>  
> +
> +    XENO_ASSERT(xnpod_root_p(), return -EPERM;);
> +
>      down_write(&user_info->mm->mmap_sem);
>      err = do_munmap(user_info->mm, (unsigned long)ptr, len);
>      up_write(&user_info->mm->mmap_sem);
> 
> </nucleus></rtdm></nucleus></nucleus></nucleus></nucleus>