# sched.c

Go to the documentation of this file.

    00001 /*****************************************************************************************
    00002  Copyright (c) 2002-2004 The UbixOS Project
    00003  All rights reserved.
    00004
    00005  Redistribution and use in source and binary forms, with or without modification, are
    00006  permitted provided that the following conditions are met:
    00007
    00008  Redistributions of source code must retain the above copyright notice, this list of
    00009  conditions, the following disclaimer and the list of authors.  Redistributions in binary
    00010  form must reproduce the above copyright notice, this list of conditions, the following
    00011  disclaimer and the list of authors in the documentation and/or other materials provided
    00012  with the distribution. Neither the name of the UbixOS Project nor the names of its
    00013  contributors may be used to endorse or promote products derived from this software
    00014  without specific prior written permission.
    00015
    00016  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
    00017  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
    00018  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
    00019  THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    00020  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
    00021  OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    00022  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
    00023  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
    00024  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    00025
    00026  $Id: sched_8c-source.html 88 2016-01-12 00:11:29Z reddawg $
    00027
    00028 *****************************************************************************************/
    00029
    00030 #include <ubixos/sched.h>
    00031 #include <ubixos/kpanic.h>
    00032 #include <ubixos/spinlock.h>
    00033 #include <ubixos/endtask.h>
    00034 #include <vfs/mount.h>
    00035 #include <lib/kmalloc.h>
    00036 #include <lib/kprintf.h>
    00037 #include <vmm/vmm.h>
    00038 #include <sys/gdt.h>
    00039 #include <sys/idt.h>
    00040 #include <sys/kern_descrip.h>
    00041 #include <isa/8259.h>
    00042 #include <string.h>
    00043 #include <assert.h>
    00044
    00045 #include <ubixos/spinlock.h>
    00046
    00047 static kTask_t *taskList = 0x0;
    00048 static kTask_t *delList  = 0x0;
    00049 static uInt32  nextID    = -1;
    00050
    00051 kTask_t *_current = 0x0;
    00052 kTask_t *_usedMath = 0x0;
    00053
    00054 static spinLock_t schedulerSpinLock = SPIN_LOCK_INITIALIZER;
    00055
    00056 /************************************************************************
    00057
    00058 Function: int sched_init()
    00059
    00060 Description: This function is used to enable the kernel scheduler
    00061
    00062 Notes:
    00063
    00064 02/20/2004 - Approved for quality
    00065
    00066 ************************************************************************/
    00067
    00068
    00069 int sched_init() {
    00070   taskList = (kTask_t *)kmalloc(sizeof(kTask_t));
    00071   if(taskList == 0x0)
    00072         kpanic("Unable to create task list");
    00073
    00074   taskList->id = nextID++;
    00075
    00076   /* Print out information on scheduler */
    00077   kprintf("sched0 - Address: [0x%X]\n", taskList);
    00078
    00079   /* Return so we know everything went well */
    00080   return(0x0);
    00081   }
    00082
    00083
    00084 void sched(){
    00085   uInt32 memAddr   = 0x0;
    00086   kTask_t *tmpTask = 0x0;
    00087   kTask_t *delTask = 0x0;
    00088
    00089   if (!spinTryLock(&schedulerSpinLock))
    00090         return;
    00091
    00092   tmpTask = _current->next;
    00093   //outportByte(0xE9,_current->id + '0');
    00094   schedStart:
    00095
    00096   /* Yield the next task from the current prio queue */
    00097   for (;tmpTask != 0x0; tmpTask = tmpTask->next) {
    00098     if (tmpTask->state > 0x0) {
    00099       _current = tmpTask;
    00100       if (_current->state == FORK)
    00101         _current->state = READY;
    00102       break;
    00103       }
    00104     else if (tmpTask->state == DEAD)
    00105       {
    00106         delTask  = tmpTask;
    00107         tmpTask  = tmpTask->next;
    00108         sched_deleteTask(delTask->id);
    00109         sched_addDelTask(delTask);
    00110         goto schedStart;
    00111       }
    00112     }
    00113
    00114         /* Finished all the tasks, restarting the list */
    00115         if (0x0 == tmpTask) {
    00116                 tmpTask = taskList;
    00117                 goto schedStart;
    00118         }
    00119
    00120
    00121         if (_current->state > 0x0) {
    00122                 if (_current->oInfo.v86Task == 0x1)
    00123                         irqDisable(0x0);
    00124                 asm("cli");
    00125                 memAddr = (uInt32)&(_current->tss);
    00126                 ubixGDT[4].descriptor.baseLow  = (memAddr & 0xFFFF);
    00127                 ubixGDT[4].descriptor.baseMed  = ((memAddr >> 16) & 0xFF);
    00128                 ubixGDT[4].descriptor.baseHigh = (memAddr >> 24);
    00129                 ubixGDT[4].descriptor.access   = '\x89';
    00130                 spinUnlock(&schedulerSpinLock);
    00131                 asm("sti");
    00132                 asm("ljmp $0x20,$0\n");
    00133         }
    00134         else
    00135         {
    00136                 spinUnlock(&schedulerSpinLock);
    00137         }
    00138
    00139         return;
    00140 }
    00141
    00142
    00143 kTask_t *schedNewTask() {
    00144   int i = 0;
    00145   kTask_t *tmpTask  = (kTask_t *)kmalloc(sizeof(kTask_t));
    00146   struct file *fp = 0x0;
    00147   if (tmpTask == 0x0)
    00148     kpanic("Error: schedNewTask() - kmalloc failed trying to initialize a new task struct\n");
    00149
    00150   memset(tmpTask,0x0,sizeof(kTask_t));
    00151   /* Filling in tasks attrs */
    00152   tmpTask->usedMath   = 0x0;
    00153   tmpTask->state      = NEW;
    00154
    00155   /* HACK */
    00156   for (i=0;i<3;i++) {
    00157     fp = kmalloc(sizeof(struct file));
    00158     tmpTask->td.o_files[i] = (u_int32_t)fp;
    00159     fp->f_flag = 0x4;
    00160     }
    00161
    00162   spinLock(&schedulerSpinLock);
    00163   tmpTask->id         = nextID++;
    00164   tmpTask->next  = taskList;
    00165   tmpTask->prev  = 0x0;
    00166   taskList->prev = tmpTask;
    00167   taskList       = tmpTask;
    00168
    00169   spinUnlock(&schedulerSpinLock);
    00170
    00171   return(tmpTask);
    00172   }
    00173
    00174
    00175 int sched_deleteTask(pidType id) {
    00176   kTask_t *tmpTask = 0x0;
    00177
    00178   /* Checking each task from the prio queue */
    00179   for (tmpTask = taskList; tmpTask != 0x0; tmpTask = tmpTask->next) {
    00180    if (tmpTask->id == id) {
    00181      if (tmpTask->prev != 0x0)
    00182        tmpTask->prev->next = tmpTask->next;
    00183      if (tmpTask->next != 0x0)
    00184        tmpTask->next->prev = tmpTask->prev;
    00185      if (taskList == tmpTask)
    00186        taskList = tmpTask->next;
    00187
    00188      return(0x0);
    00189      }
    00190    }
    00191   return(0x1);
    00192   }
    00193
    00194 int  sched_addDelTask(kTask_t *tmpTask) {
    00195   tmpTask->next = delList;
    00196   tmpTask->prev = 0x0;
    00197   if (delList != 0x0)
    00198     delList->prev = tmpTask;
    00199   delList       = tmpTask;
    00200   return(0x0);
    00201   }
    00202
    00203 kTask_t *sched_getDelTask() {
    00204   kTask_t *tmpTask = 0x0;
    00205
    00206   if (delList == 0x0)
    00207     return(0x0);
    00208
    00209   tmpTask = delList;
    00210   delList = delList->next;
    00211   return(tmpTask);
    00212   }
    00213
    00214
    00215 kTask_t *
    00216 schedFindTask(uInt32 id)
    00217 {
    00218         kTask_t *tmpTask = 0x0;
    00219
    00220         for (tmpTask = taskList; tmpTask; tmpTask = tmpTask->next) {
    00221                 if (tmpTask->id == id)
    00222                         return(tmpTask);
    00223         }
    00224
    00225         return(0x0);
    00226 }
    00227
    00228
    00229 /************************************************************************
    00230
    00231  Function: void schedEndTask()
    00232
    00233  Description: This function will end a task
    00234
    00235  Notes:
    00236
    00237   02/20/2004 - Approved for quality
    00238
    00239 ************************************************************************/
    00240 void
    00241 schedEndTask(pidType pid) {
    00242         endTask(_current->id);
    00243         sched_yield();
    00244 }
    00245
    00246 /************************************************************************
    00247
    00248 Function: int schedEndTask()
    00249
    00250 Description: This function will yield a task
    00251
    00252 Notes:
    00253
    00254 02/20/2004 - Approved for quality
    00255
    00256 ************************************************************************/
    00257
    00258 void
    00259 sched_yield() {
    00260   sched();
    00261   }
    00262
    00263 /*
    00264 asm(
    00265   ".globl sched_yield \n"
    00266   "sched_yield:       \n"
    00267   "  cli              \n"
    00268   "  call sched       \n"
    00269   );
    00270 */
    00271
    00272 /************************************************************************
    00273
    00274 Function: int sched_setStatus(pidType pid,tState state)
    00275
    00276 Description: Change the tasks status
    00277
    00278 Notes:
    00279
    00280 ************************************************************************/
    00281 int sched_setStatus(pidType pid,tState state) {
    00282   kTask_t *tmpTask = schedFindTask(pid);
    00283   if (tmpTask == 0x0)
    00284     return(0x1);
    00285   tmpTask->state = state;
    00286   return(0x0);
    00287   }
    00288
    00289 /***
    00290  END
    00291  ***/
    00292