rom/exec/signal.c

   1 /*
   2     Copyright © 1995-2015, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Send some signal to a given task
   6     Lang: english
   7 */
   8
   9 #include <exec/execbase.h>
  10 #include <aros/libcall.h>
  11 #include <proto/exec.h>
  12 #include <aros/debug.h>
  13
  14 #include "exec_intern.h"
  15
  16 /*****************************************************************************
  17
  18     NAME */
  19
  20         AROS_LH2(void, Signal,
  21
  22 /*  SYNOPSIS */
  23         AROS_LHA(struct Task *,     task,      A1),
  24         AROS_LHA(ULONG,             signalSet, D0),
  25
  26 /*  LOCATION */
  27         struct ExecBase *, SysBase, 54, Exec)
  28
  29 /*  FUNCTION
  30         Send some signals to a given task. If the task is currently waiting
  31         on these signals, has a higher priority as the current one and if
  32         taskswitches are allowed the new task begins to run immediately.
  33
  34     INPUTS
  35         task      - Pointer to task structure.
  36         signalSet - The set of signals to send to the task.
  37
  38     RESULT
  39
  40     NOTES
  41         This function may be used from interrupts.
  42
  43     EXAMPLE
  44
  45     BUGS
  46
  47     SEE ALSO
  48         AllocSignal(), FreeSignal(), Wait(), SetSignal(), SetExcept()
  49
  50     INTERNALS
  51
  52     HISTORY
  53
  54 ******************************************************************************/
  55 {
  56     AROS_LIBFUNC_INIT
  57
  58 #if defined(__AROSEXEC_SMP__)
  59     spinlock_t *task_listlock = NULL;
  60 #endif
  61
  62     /* Protect the task lists against other tasks that may use Signal(). */
  63 #if defined(__AROSEXEC_SMP__)
  64     switch (task->tc_State)
  65     {
  66         case TS_RUN:
  67             task_listlock =&PrivExecBase(SysBase)->TaskRunningSpinLock;
  68             break;
  69         case TS_WAIT:
  70             task_listlock = &PrivExecBase(SysBase)->TaskWaitSpinLock;
  71             break;
  72         default:
  73             task_listlock = &PrivExecBase(SysBase)->TaskReadySpinLock;
  74             break;
  75     }
  76     EXEC_SPINLOCK_LOCK(task_listlock, SPINLOCK_MODE_WRITE);
  77 #endif
  78     Disable();
  79
  80     /* Set the signals in the task structure. */
  81     task->tc_SigRecvd |= signalSet;
  82
  83     /* Do those bits raise exceptions? */
  84     if (task->tc_SigExcept & task->tc_SigRecvd)
  85     {
  86         /* Yes. Set the exception flag. */
  87         task->tc_Flags |= TF_EXCEPT;
  88
  89         /* task is running (Signal() called from within interrupt)? Raise the exception or defer it for later. */
  90         if (task->tc_State == TS_RUN)
  91         {
  92 #if defined(__AROSEXEC_SMP__)
  93             EXEC_SPINLOCK_UNLOCK(task_listlock);
  94 #endif
  95             /* Order a reschedule */
  96             Reschedule();
  97
  98             /* All done. */
  99             Enable();
 100
 101             return;
 102         }
 103     }
 104
 105     /*
 106         Is the task receiving the signals waiting on them
 107         (or on a exception) ?
 108     */
 109     if ((task->tc_State == TS_WAIT) &&
 110        (task->tc_SigRecvd&(task->tc_SigWait | task->tc_SigExcept)))
 111     {
 112         /* Yes. Move him to the ready list. */
 113         task->tc_State = TS_READY;
 114         Remove(&task->tc_Node);
 115 #if defined(__AROSEXEC_SMP__)
 116         EXEC_SPINLOCK_UNLOCK(task_listlock);
 117         Enable();
 118         task_listlock = EXEC_SPINLOCK_LOCK(&PrivExecBase(SysBase)->TaskReadySpinLock, SPINLOCK_MODE_WRITE);
 119         Disable();
 120 #endif
 121         Enqueue(&SysBase->TaskReady, &task->tc_Node);
 122
 123         /* Has it a higher priority as the current one? */
 124         if (task->tc_Node.ln_Pri > GET_THIS_TASK->tc_Node.ln_Pri)
 125         {
 126             /*
 127                 Yes. A taskswitch is necessary. Prepare one if possible.
 128                 (If the current task is not running it is already moved)
 129             */
 130             if (GET_THIS_TASK->tc_State == TS_RUN)
 131             {
 132 #if defined(__AROSEXEC_SMP__)
 133                 EXEC_SPINLOCK_UNLOCK(task_listlock);
 134                 task_listlock = NULL;
 135 #endif
 136                 Reschedule();
 137             }
 138         }
 139     }
 140
 141 #if defined(__AROSEXEC_SMP__)
 142     if (task_listlock)
 143     {
 144         EXEC_SPINLOCK_UNLOCK(task_listlock);
 145     }
 146 #endif
 147     Enable();
 148
 149     AROS_LIBFUNC_EXIT
 150 }
 151