rom/exec/newaddtask.c

   1 /*
   2     Copyright © 1995-2015, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Add a task.
   6     Lang: english
   7 */
   8
   9 #include <exec/execbase.h>
  10 #include <exec/memory.h>
  11 #include <utility/tagitem.h>
  12 #include <aros/debug.h>
  13 #include <aros/libcall.h>
  14 #include <proto/exec.h>
  15
  16 #include "etask.h"
  17 #include "exec_util.h"
  18 #include "exec_debug.h"
  19 #include "taskstorage.h"
  20
  21 #if defined(__AROSEXEC_SMP__)
  22 #include <proto/kernel.h>
  23 #endif
  24
  25 /*****************************************************************************
  26
  27     NAME */
  28
  29         AROS_LH4(APTR, NewAddTask,
  30
  31 /*  SYNOPSIS */
  32         AROS_LHA(struct Task *,     task,      A1),
  33         AROS_LHA(APTR,              initialPC, A2),
  34         AROS_LHA(APTR,              finalPC,   A3),
  35         AROS_LHA(struct TagItem *,  tagList,   A4),
  36
  37 /*  LOCATION */
  38         struct ExecBase *, SysBase, 176, Exec)
  39
  40 /*  FUNCTION
  41         Add a new task to the system. If the new task has the highest
  42         priority of all and task switches are allowed it will be started
  43         immediately.
  44         Certain task fields should be intitialized and a stack must be
  45         allocated before calling this function. tc_SPReg will be used as the
  46         starting location for the stack pointer, i.e. a part of the stack can
  47         be reserved to pass the task some initial arguments.
  48         Memory can be added to the tc_MemEntry list and will be freed when the
  49         task dies. The new task's registers are set to 0.
  50
  51     INPUTS
  52         task      - Pointer to task structure.
  53         initialPC - Entry point for the new task.
  54         finalPC   - Routine that is called if the initialPC() function returns.
  55                     A NULL pointer installs the default finalizer.
  56
  57     RESULT
  58         The address of the new task or NULL if the operation failed (can only
  59         happen with TF_ETASK set - currenty not implemented).
  60
  61     NOTES
  62         This function is private. Use MorphOS-compatible NewCreateTaskA()
  63         in your applications.
  64
  65     EXAMPLE
  66
  67     BUGS
  68
  69     SEE ALSO
  70         RemTask()
  71
  72     INTERNALS
  73
  74     HISTORY
  75
  76 ******************************************************************************/
  77 {
  78     AROS_LIBFUNC_INIT
  79
  80     ASSERT_VALID_PTR(task);
  81
  82 #if defined(__AROSEXEC_SMP__)
  83     int cpunum = KrnGetCPUNumber();
  84 #endif
  85
  86     /* Sigh - you should provide a name for your task. */
  87     if (task->tc_Node.ln_Name == NULL)
  88         task->tc_Node.ln_Name = "unknown task";
  89
  90     DADDTASK("NewAddTask (0x%p (\"%s\"), 0x%p, 0x%p)", task, task->tc_Node.ln_Name, initialPC, finalPC);
  91
  92     /* Initialize the memory entry list if the caller forgot */
  93     if (!task->tc_MemEntry.lh_Head)
  94         NEWLIST(&task->tc_MemEntry);
  95
  96     DADDTASK("NewAddTask MemEntry head: 0x%p", GetHead(&task->tc_MemEntry.lh_Head));
  97
  98     /* Set node type to NT_TASK if not set to something else. */
  99     if (!task->tc_Node.ln_Type)
 100         task->tc_Node.ln_Type = NT_TASK;
 101
 102     /* This is moved into SysBase at the tasks's startup */
 103     task->tc_IDNestCnt = -1;
 104     task->tc_TDNestCnt = -1;
 105
 106     task->tc_State = TS_ADDED;
 107     task->tc_Flags = 0;
 108
 109     task->tc_SigWait = 0;
 110     task->tc_SigRecvd = 0;
 111     task->tc_SigExcept = 0;
 112
 113     /* Signals default to all system signals allocated. */
 114     if (task->tc_SigAlloc == 0)
 115         task->tc_SigAlloc = SysBase->TaskSigAlloc;
 116
 117     /* Currently only used for segmentation violation */
 118     if (task->tc_TrapCode == NULL)
 119         task->tc_TrapCode = SysBase->TaskTrapCode;
 120
 121     if (task->tc_ExceptCode == NULL)
 122         task->tc_ExceptCode = SysBase->TaskExceptCode;
 123
 124     /*
 125      * EXECF_StackSnoop can be set or reset at runtime.
 126      * However task's stack is either snooped or not, it's problematic
 127      * to turn it on at runtime. So we initialize it when the task starts up.
 128      */
 129     if (PrivExecBase(SysBase)->IntFlags & EXECF_StackSnoop)
 130         task->tc_Flags |= TF_STACKCHK;
 131
 132     /* Initialize ETask */
 133     if (!InitETask(task))
 134         return NULL;
 135
 136     /* Get new stackpointer. */
 137     if (task->tc_SPReg == NULL)
 138         task->tc_SPReg = (UBYTE *)(task->tc_SPUpper) - SP_OFFSET;
 139
 140 #ifdef AROS_STACKALIGN
 141     if ((IPTR)task->tc_SPReg & (AROS_STACKALIGN - 1))
 142     {
 143         DADDTASK("NewAddTask with unaligned stack pointer (0x%p)! Fixing...", task->tc_SPReg);
 144         task->tc_SPReg = (APTR)((IPTR)task->tc_SPReg & ~(AROS_STACKALIGN - 1));
 145     }
 146 #endif
 147     DADDTASK("NewAddTask: SPLower: 0x%p SPUpper: 0x%p SP: 0x%p", task->tc_SPLower, task->tc_SPUpper, task->tc_SPReg);
 148
 149     if (task->tc_Flags & TF_STACKCHK)
 150     {
 151         UBYTE *startfill, *endfill;
 152
 153         startfill = (UBYTE *)task->tc_SPLower;
 154         endfill   = ((UBYTE *)task->tc_SPReg) - 16;
 155
 156         while (startfill <= endfill)
 157         {
 158             *startfill++ = 0xE1;
 159         }
 160     }
 161
 162     /* Default finalizer? */
 163     if (finalPC == NULL)
 164         finalPC = SysBase->TaskExitCode;
 165
 166     /* Init new context. */
 167     if (!PrepareContext(task, initialPC, finalPC, tagList, SysBase))
 168     {
 169         CleanupETask(task);
 170         return NULL;
 171     }
 172
 173     /* Set the task flags for switch and launch. */
 174     if(task->tc_Switch)
 175         task->tc_Flags|=TF_SWITCH;
 176
 177     if(task->tc_Launch)
 178         task->tc_Flags|=TF_LAUNCH;
 179
 180     /*
 181         Protect the task lists. This must be done with Disable() because
 182         of Signal() which is usable from interrupts and may change those
 183         lists.
 184      */
 185
 186 #if defined(__AROSEXEC_SMP__)
 187     EXEC_SPINLOCK_LOCK(&PrivExecBase(SysBase)->TaskReadySpinLock, SPINLOCK_MODE_WRITE);
 188 #endif
 189     Disable();
 190
 191     /* Add the new task to the ready list. */
 192     task->tc_State = TS_READY;
 193     Enqueue(&SysBase->TaskReady, &task->tc_Node);
 194 #if defined(__AROSEXEC_SMP__)
 195     EXEC_SPINLOCK_UNLOCK(&PrivExecBase(SysBase)->TaskReadySpinLock);
 196 #endif
 197
 198     /*
 199         Determine if a task switch is necessary. (If the new task has a
 200         higher priority than the current one and the current one
 201         is still active.) If the current task isn't of type TS_RUN it
 202         is already gone.
 203     */
 204
 205     if (
 206 #if defined(__AROSEXEC_SMP__)
 207         ((IntETask(task->tc_UnionETask.tc_ETask)->iet_CpuAffinity & KrnGetCPUMask(cpunum)) == KrnGetCPUMask(cpunum)) &&
 208 #endif
 209         task->tc_Node.ln_Pri > GET_THIS_TASK->tc_Node.ln_Pri &&
 210         GET_THIS_TASK->tc_State == TS_RUN)
 211     {
 212         D(bug("[AddTask] Rescheduling...\n");)
 213
 214         /* Reschedule() will take care about disabled task switching automatically */
 215         Reschedule();
 216     }
 217 #if defined(__AROSEXEC_SMP__)
 218     else
 219     {
 220         bug("[Exec] AddTask:\n");
 221     }
 222 #endif
 223
 224     Enable();
 225
 226     DADDTASK("Added task 0x%p", task);
 227     return task;
 228
 229     AROS_LIBFUNC_EXIT
 230 } /* NewAddTask */