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ubixos / src / sys / kernel / sched.c
@reddawg reddawg on 16 Sep 2004 11 KB Demo Release
/*****************************************************************************************
 Copyright (c) 2002-2004 The UbixOS Project
 All rights reserved.

 Redistribution and use in source and binary forms, with or without modification, are
 permitted provided that the following conditions are met:

 Redistributions of source code must retain the above copyright notice, this list of
 conditions, the following disclaimer and the list of authors.  Redistributions in binary
 form must reproduce the above copyright notice, this list of conditions, the following
 disclaimer and the list of authors in the documentation and/or other materials provided
 with the distribution. Neither the name of the UbixOS Project nor the names of its
 contributors may be used to endorse or promote products derived from this software
 without specific prior written permission.

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 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 $Id$

*****************************************************************************************/

#include <ubixos/sched.h>
#include <ubixos/kpanic.h>
#include <ubixos/spinlock.h>
#include <ubixos/endtask.h>
#include <ubixos/vitals.h>
#include <vfs/mount.h>
#include <lib/kmalloc.h>
#include <lib/kprintf.h>
#include <vmm/vmm.h>
#include <sys/gdt.h>
#include <sys/idt.h>
#include <isa/8259.h>
#include <string.h>
#include <assert.h>

#include <ubixos/spinlock.h>

static kTask_t *taskList = 0x0;
static kTask_t *delList  = 0x0;
static uInt32  nextID    = -1;

kTask_t *_current = 0x0;
kTask_t *_usedMath = 0x0;

static spinLock_t schedulerSpinLock = SPIN_LOCK_INITIALIZER;

/************************************************************************

Function: int sched_init()

Description: This function is used to enable the kernel scheduler

Notes:

02/20/2004 - Approved for quality

************************************************************************/


int sched_init() {        
  taskList = (kTask_t *)kmalloc(sizeof(kTask_t));
   
  taskList->id = nextID++;

  /* Print out information on scheduler */
  kprint("sched0 - Address: [0x%X]\n", taskList);
        
  /* Return so we know everything went well */
  return(0x0); 
  }


void sched(){
  uInt32 memAddr   = 0x0;
  kTask_t *tmpTask = 0x0;
  kTask_t *delTask = 0x0;
  
  if (!spinTryLock(&schedulerSpinLock))
  	return;
  
  tmpTask = _current->next;
  //outportByte(0xE9,_current->id + '0');
  schedStart:
  /* Yield the next task from the current prio queue */
  for (;tmpTask != 0x0; tmpTask = tmpTask->next) {
    if (tmpTask->state > 0x0) {
      _current = tmpTask;
      if (_current->state == FORK)
        _current->state = READY;
      break;
      }
    else if (_current->state == DEAD)
      {
        delTask  = tmpTask;
        tmpTask  = tmpTask->next;
        sched_deleteTask(delTask->id);
        sched_addDelTask(delTask);
        goto schedStart;
      }
    }

        /* Finished all the tasks, restarting the list */
        if (0x0 == tmpTask) {
                tmpTask = taskList;
                goto schedStart;
        }
        
        
        if (_current->state > 0x0) {
                if (_current->oInfo.v86Task == 0x1)
                        irqDisable(0x0);
                asm("cli");
                memAddr = (uInt32)&(_current->tss);
                ubixGDT[4].descriptor.baseLow  = (memAddr & 0xFFFF);
                ubixGDT[4].descriptor.baseMed  = ((memAddr >> 16) & 0xFF);
                ubixGDT[4].descriptor.baseHigh = (memAddr >> 24);
                ubixGDT[4].descriptor.access   = '\x89';
		spinUnlock(&schedulerSpinLock);
		asm("sti");
		asm("ljmp $0x20,$0\n");
        }
	else
	{
		spinUnlock(&schedulerSpinLock);
	}
	
        return;
}


kTask_t *schedNewTask() {
  kTask_t *tmpTask  = (kTask_t *)kmalloc(sizeof(kTask_t));
  if (tmpTask == 0x0)
    kpanic("Error: schedNewTask() - kmalloc failed trying to initialize a new task struct\n");

  memset(tmpTask,0x0,sizeof(kTask_t)); 
  /* Filling in tasks attrs */
  tmpTask->usedMath   = 0x0;
  tmpTask->id         = nextID++;
  tmpTask->state      = NEW;

  spinLock(&schedulerSpinLock);
  
  tmpTask->next  = taskList;
  tmpTask->prev  = 0x0;
  taskList->prev = tmpTask;
  taskList       = tmpTask;

  spinUnlock(&schedulerSpinLock);
  
  return(tmpTask);
  }


int sched_deleteTask(pidType id) {
  kTask_t *tmpTask = 0x0; 

  /* Checking each task from the prio queue */
  for (tmpTask = taskList; tmpTask != 0x0; tmpTask = tmpTask->next) {
   if (tmpTask->id == id) {
     if (tmpTask->prev != 0x0)
       tmpTask->prev->next = tmpTask->next;
     if (tmpTask->next != 0x0)
       tmpTask->next->prev = tmpTask->prev;
     if (taskList == tmpTask)
       taskList = tmpTask->next;
      
     return(0x0);
     }
   }
  return(0x1);
  }
  
int  sched_addDelTask(kTask_t *tmpTask) {
  tmpTask->next = delList;
  tmpTask->prev = 0x0;
  if (delList != 0x0)
    delList->prev = tmpTask;
  delList       = tmpTask;
  return(0x0);
  }
  
kTask_t *sched_getDelTask() {
  kTask_t *tmpTask = 0x0;
  
  if (delList == 0x0)
    return(0x0);
    
  tmpTask = delList;
  delList = delList->next;
  return(tmpTask);
  }


kTask_t * 
schedFindTask(uInt32 id) 
{
        kTask_t *tmpTask = 0x0; 

        for (tmpTask = taskList; tmpTask; tmpTask = tmpTask->next) {
                if (tmpTask->id == id)
                        return(tmpTask);
        }

        return(0x0);
}


/************************************************************************

 Function: void schedEndTask()

 Description: This function will end a task

 Notes:

  02/20/2004 - Approved for quality

************************************************************************/
void 
schedEndTask(pidType pid) {
        endTask(_current->id);
        sched_yield();
}

/************************************************************************

Function: int schedEndTask()

Description: This function will yield a task 

Notes:

02/20/2004 - Approved for quality

************************************************************************/

void 
sched_yield() {
  sched();
  }

/*
asm(
  ".globl sched_yield \n"
  "sched_yield:       \n"
  "  cli              \n"
  "  call sched       \n"
  );
*/

/************************************************************************

Function: int sched_setStatus(pidType pid,tState state)

Description: Change the tasks status

Notes:

************************************************************************/
int sched_setStatus(pidType pid,tState state) {
  kTask_t *tmpTask = schedFindTask(pid);
  if (tmpTask == 0x0)
    return(0x1);
  tmpTask->state = state;
  return(0x0);
  }

/***
 $Log$
 Revision 1.61  2004/09/15 21:25:33  reddawg
 Fixens

 Revision 1.60  2004/09/11 22:21:11  reddawg
 oInfo.cwd is now an array no longer a pointer..

 Revision 1.59  2004/09/11 22:17:52  reddawg
 hmm..

 Revision 1.58  2004/09/11 21:45:44  reddawg
 Fixed sched to work with gcc 3.3

 Revision 1.57  2004/09/11 21:38:00  reddawg
 Fixed a few problems

 Revision 1.56  2004/09/11 21:31:54  apwillia
 Fix DEAD problem

 Revision 1.55  2004/09/11 21:30:37  apwillia
 Fix race conditions in net thread and scheduler

 Revision 1.54  2004/09/11 17:39:51  apwillia
 CHRIS: Don't mess with scheduler structures outside the schedulergvim endtask.c  Finally fixed the race condition.

 Revision 1.53  2004/09/11 14:55:25  reddawg
 memset newly allocated tasks

 Revision 1.52  2004/09/11 12:11:11  reddawg
 Cleaning up the VFS more changes to follow...

 Revision 1.51  2004/09/08 22:16:02  reddawg
 Fixens

 Revision 1.50  2004/09/08 21:19:32  reddawg
 All good now

 Revision 1.49  2004/09/07 22:05:59  reddawg
 only changes I have to contribute

 Revision 1.48  2004/09/07 21:54:38  reddawg
 ok reverted back to old scheduling for now....

 Revision 1.30  2004/08/09 12:58:05  reddawg
 let me know when you got the surce

 Revision 1.29  2004/08/06 22:43:04  reddawg
 ok

 Revision 1.28  2004/08/06 22:32:16  reddawg
 Ubix Works Again

 Revision 1.26  2004/08/02 18:50:13  reddawg
 Updates to make some variable volatile to make work with gcc 3.3. However there are still some issues but we have not caused new issues with gcc 2.95

 Revision 1.25  2004/08/01 20:24:51  reddawg
 Fixens

 Revision 1.24  2004/08/01 17:50:46  reddawg
 Fixens

 Revision 1.23  2004/07/29 21:32:16  reddawg
 My quick lunchs breaks worth of updates....

 Revision 1.22  2004/07/28 16:29:30  reddawg
 old sched back

 Revision 1.20  2004/07/25 06:04:00  reddawg
 Last of my fixes for the morning

 Revision 1.19  2004/07/24 15:12:56  reddawg
 Now I'm current

 Revision 1.18  2004/07/21 10:02:09  reddawg
 devfs: renamed functions
 device system: renamed functions
 fdc: fixed a few potential bugs and cleaned up some unused variables
 strol: fixed definition
 endtask: made it print out freepage debug info
 kmalloc: fixed a huge memory leak we had some unhandled descriptor insertion so some descriptors were lost
 ld: fixed a pointer conversion
 file: cleaned up a few unused variables
 sched: broke task deletion
 kprintf: fixed ogPrintf definition

 Revision 1.17  2004/07/20 18:58:24  reddawg
 Few fixes

 Revision 1.16  2004/07/20 18:51:00  reddawg
 sched: hold that was my error

 Revision 1.15  2004/07/19 02:32:21  reddawg
 sched: we now set task status to dead which then makes the scheduler do some clean it could be some minor overhead but i feel this is our most efficient approach right now to prevent corruption of the queues

 Revision 1.14  2004/07/19 01:56:31  reddawg
 schedDeleteTask: I am pondering the possability that this could not finish in a quantum....

 Revision 1.13  2004/07/18 05:24:15  reddawg
 Fixens

 Revision 1.12  2004/07/09 13:23:20  reddawg
 sched: schedInit to sched_init
 Adjusted initialization routines

 Revision 1.11  2004/06/22 14:03:10  solar
 Making the task queue with priorities functional

 Revision 1.10  2004/06/18 13:05:47  solar
 Changed the scheduler by adding the first rudiments of priority; vitals.c initializes the system's default quantum to 40

 Revision 1.9  2004/06/04 13:29:56  reddawg
 libc: modified mkdir(); interface
 kpanic: kPanic(); now says kPanic: %s
 system: now reboots when receives message for reboot
         also when command start sde is received by system the STD is started

 Revision 1.8  2004/05/25 16:10:46  reddawg
 Spin Locks

 Revision 1.7  2004/05/21 21:15:04  reddawg
 Fixed a few bugs which prevented the system from loadin

 Revision 1.6  2004/05/21 15:49:13  reddawg
 The os does better housekeeping now when a task is exited

 Revision 1.5  2004/05/21 12:44:17  reddawg
 Cleaned Up

 Revision 1.4  2004/05/19 04:07:43  reddawg
 kmalloc(size,pid) no more it is no kmalloc(size); the way it should of been

 Revision 1.3  2004/05/15 02:30:28  reddawg
 Lots of changes


 END
 ***/