Exemplo n.º 1
0
/*===========================================================================*
 *                  do_rt_set_rm                                             *
 *===========================================================================*/
PRIVATE int do_rt_set_rm(message *m_ptr, struct proc *rp)
{
  struct proc *xp;    
    
  /* if rm_prio_policy equals PRIO_UNIQUE the priority of a
   * process scheduled with RM should be unique. We will have to
   * loop through the process table to check if there is no other process
   * with this priority.
   */
  if (rm_prio_policy == PRIO_UNIQUE) {
      for (xp = BEG_PROC_ADDR; xp < END_PROC_ADDR; ++xp) {
          if (xp->p_rts_flags != SLOT_FREE && 
              is_rtp(xp) && xp->p_rt_priority == m_ptr->RM_PRIO) {
              return (EINVAL);
          }    
      }
  }    
 
  if ( rp->p_rts_flags == 0) {
      /* Should not happen normally.
       * A process is runnable if p_rts_flags is zero.
       * The process requesting to be real-time should be
       * blocked waiting for a reply from PM 
       * and thus p_rts_flags should not be zero.
       * Still we remove the process from the scheduling queue.
       */
       lock_dequeue(rp);
  }

  /* Now we can change the process structure.
   * First make sure this process will be recognized
   * as a real-time process.
   */
   rp->p_rt = 1;
      
  /* Set the current and maximum priority to the
   * real-time queue.
   */
  rp->p_max_priority = rp->p_priority = RT_Q;

  /* set the static priority */
  rp->p_rt_priority = m_ptr->RM_PRIO;

  if ( rp->p_rts_flags == 0) {
      /* Should not happen normally.
       * See above. Add process to the scheduling queue.
       */
      lock_enqueue(rp);
  }

  return (OK);
}    
Exemplo n.º 2
0
/*===========================================================================*
 *				  do_nice				     *
 *===========================================================================*/
PUBLIC int do_nice(message *m_ptr)
{
/* Change process priority or stop the process. */
  int proc_nr, pri, new_q ;
  register struct proc *rp;

  /* Extract the message parameters and do sanity checking. */
  if(!isokendpt(m_ptr->PR_ENDPT, &proc_nr)) return EINVAL;
  if (iskerneln(proc_nr)) return(EPERM);
  
  pri = m_ptr->PR_PRIORITY;
  rp = proc_addr(proc_nr);

  if (is_rtp(rp)) return (EPERM); /* don't allow nice for RT processes */

  if (pri == PRIO_STOP) {

      /* Take process off the scheduling queues. */
      lock_dequeue(rp);
      rp->p_rts_flags |= NO_PRIORITY;
      return(OK);
  }
  else if (pri >= PRIO_MIN && pri <= PRIO_MAX) {

      /* The value passed in is currently between PRIO_MIN and PRIO_MAX. 
       * We have to scale this between MIN_USER_Q and MAX_USER_Q to match 
       * the kernel's scheduling queues.
       */
      new_q = MAX_USER_Q + (pri-PRIO_MIN) * (MIN_USER_Q-MAX_USER_Q+1) / 
          (PRIO_MAX-PRIO_MIN+1);
      if (new_q < MAX_USER_Q) new_q = MAX_USER_Q;	/* shouldn't happen */
      if (new_q > MIN_USER_Q) new_q = MIN_USER_Q;	/* shouldn't happen */

      if (new_q == RT_Q && !is_rtp(rp)) return (EINVAL); /* don't allow other processes in the RT queue */
      
      /* Make sure the process is not running while changing its priority. 
       * Put the process back in its new queue if it is runnable.
       */
      lock_dequeue(rp);
      rp->p_max_priority = rp->p_priority = new_q;
      if (! rp->p_rts_flags) lock_enqueue(rp);

      return(OK);
  }
  return(EINVAL);
}
Exemplo n.º 3
0
/*===========================================================================*
 *				  do_quantum				     *
 *===========================================================================*/
PUBLIC int do_quantum(message *m_ptr)
{
  int proc_nr, quantum;
  register struct proc *rp;

  /* Individuo il numero del processo da modificare */
  proc_nr = m_ptr->PR_PROC_NR ;
  
  /* Il numero del processo non e` valido */
  if (! isokprocn(proc_nr)) return(EINVAL);

  /* Consento di modificare la dimensione del quanto solo nei processi utente */
  if (iskerneln(proc_nr)) return(EPERM);
  
  /* Nuova dimensione del quanto */
  quantum = m_ptr->PR_QUANTUM;
  
  /* Controllo che la sua dimensione rispetti i limiti consentiti */
  if (quantum < MIN_QUANTUM_SIZE) {
	  kprintf("WARNING: quantum size exceeds MIN_QUANTUM_SIZE, it will be raised to %d ticks\n",MIN_QUANTUM_SIZE);
	  quantum = MIN_QUANTUM_SIZE;
  }
  else if (quantum > MAX_QUANTUM_SIZE) {
	  kprintf("WARNING: quantum size exceeds MAX_QUANTUM_SIZE, it will be lowered to %d ticks\n",MAX_QUANTUM_SIZE);
	  quantum = MAX_QUANTUM_SIZE;
  }
 
  /* Seleziono il processo da aggiornare */ 
  rp = proc_addr(proc_nr);
 
  /* Lo rimuovo dalla coda */
  lock_dequeue(rp);

  /* Aggiorno la dimensione del quanto */
  rp->p_quantum_size = quantum;

  /* Reinserisco il processo in coda */
  if (! rp->p_rts_flags) lock_enqueue(rp);
  
  return(OK);
}
Exemplo n.º 4
0
/*===========================================================================*
 *				main                                         *
 *===========================================================================*/
PUBLIC void main()
{
/* Start the ball rolling. */
  struct boot_image *ip;	/* boot image pointer */
  register struct proc *rp;	/* process pointer */
  register struct priv *sp;	/* privilege structure pointer */
  register int i, s;
  int hdrindex;			/* index to array of a.out headers */
  phys_clicks text_base;
  vir_clicks text_clicks, data_clicks;
  reg_t ktsb;			/* kernel task stack base */
  struct exec e_hdr;		/* for a copy of an a.out header */

  /* Initialize the interrupt controller. */
  intr_init(1);

  /* Clear the process table. Anounce each slot as empty and set up mappings 
   * for proc_addr() and proc_nr() macros. Do the same for the table with 
   * privilege structures for the system processes. 
   */
  for (rp = BEG_PROC_ADDR, i = -NR_TASKS; rp < END_PROC_ADDR; ++rp, ++i) {
  	rp->p_rts_flags = SLOT_FREE;		/* initialize free slot */
	rp->p_nr = i;				/* proc number from ptr */
        (pproc_addr + NR_TASKS)[i] = rp;        /* proc ptr from number */
  }
  for (sp = BEG_PRIV_ADDR, i = 0; sp < END_PRIV_ADDR; ++sp, ++i) {
	sp->s_proc_nr = NONE;			/* initialize as free */
	sp->s_id = i;				/* priv structure index */
	ppriv_addr[i] = sp;			/* priv ptr from number */
  }

  /* Set up proc table entries for processes in boot image.  The stacks of the
   * kernel tasks are initialized to an array in data space.  The stacks
   * of the servers have been added to the data segment by the monitor, so
   * the stack pointer is set to the end of the data segment.  All the
   * processes are in low memory on the 8086.  On the 386 only the kernel
   * is in low memory, the rest is loaded in extended memory.
   */

  /* Task stacks. */
  ktsb = (reg_t) t_stack;

  for (i=0; i < NR_BOOT_PROCS; ++i) {
	ip = &image[i];				/* process' attributes */
	rp = proc_addr(ip->proc_nr);		/* get process pointer */
	rp->p_max_priority = ip->priority;	/* max scheduling priority */
	rp->p_priority = ip->priority;		/* current priority */
	rp->p_quantum_size = ip->quantum;	/* quantum size in ticks */
	rp->p_ticks_left = ip->quantum;		/* current credit */
	strncpy(rp->p_name, ip->proc_name, P_NAME_LEN); /* set process name */
	(void) get_priv(rp, (ip->flags & SYS_PROC));    /* assign structure */
	priv(rp)->s_flags = ip->flags;			/* process flags */
	priv(rp)->s_trap_mask = ip->trap_mask;		/* allowed traps */
	priv(rp)->s_call_mask = ip->call_mask;		/* kernel call mask */
	priv(rp)->s_ipc_to.chunk[0] = ip->ipc_to;	/* restrict targets */
	if (iskerneln(proc_nr(rp))) {		/* part of the kernel? */ 
		if (ip->stksize > 0) {		/* HARDWARE stack size is 0 */
			rp->p_priv->s_stack_guard = (reg_t *) ktsb;
			*rp->p_priv->s_stack_guard = STACK_GUARD;
		}
		ktsb += ip->stksize;	/* point to high end of stack */
		rp->p_reg.sp = ktsb;	/* this task's initial stack ptr */
		text_base = kinfo.code_base >> CLICK_SHIFT;
					/* processes that are in the kernel */
		hdrindex = 0;		/* all use the first a.out header */
	} else {
		hdrindex = 1 + i-NR_TASKS;	/* servers, drivers, INIT */
	}

	/* The bootstrap loader created an array of the a.out headers at
	 * absolute address 'aout'. Get one element to e_hdr.
	 */
	phys_copy(aout + hdrindex * A_MINHDR, vir2phys(&e_hdr),
						(phys_bytes) A_MINHDR);
	/* Convert addresses to clicks and build process memory map */
	text_base = e_hdr.a_syms >> CLICK_SHIFT;
	text_clicks = (e_hdr.a_text + CLICK_SIZE-1) >> CLICK_SHIFT;
	if (!(e_hdr.a_flags & A_SEP)) text_clicks = 0;	   /* common I&D */
	data_clicks = (e_hdr.a_total + CLICK_SIZE-1) >> CLICK_SHIFT;
	rp->p_memmap[T].mem_phys = text_base;
	rp->p_memmap[T].mem_len  = text_clicks;
	rp->p_memmap[D].mem_phys = text_base + text_clicks;
	rp->p_memmap[D].mem_len  = data_clicks;
	rp->p_memmap[S].mem_phys = text_base + text_clicks + data_clicks;
	rp->p_memmap[S].mem_vir  = data_clicks;	/* empty - stack is in data */

	/* Set initial register values.  The processor status word for tasks 
	 * is different from that of other processes because tasks can
	 * access I/O; this is not allowed to less-privileged processes 
	 */
	rp->p_reg.pc = (reg_t) ip->initial_pc;
	rp->p_reg.psw = (iskernelp(rp)) ? INIT_TASK_PSW : INIT_PSW;

	/* Initialize the server stack pointer. Take it down one word
	 * to give crtso.s something to use as "argc".
	 */
	if (isusern(proc_nr(rp))) {		/* user-space process? */ 
		rp->p_reg.sp = (rp->p_memmap[S].mem_vir +
				rp->p_memmap[S].mem_len) << CLICK_SHIFT;
		rp->p_reg.sp -= sizeof(reg_t);
	}
	
	/* Set ready. The HARDWARE task is never ready. */
	if (rp->p_nr != HARDWARE) {
		rp->p_rts_flags = 0;		/* runnable if no flags */
		lock_enqueue(rp);		/* add to scheduling queues */
	} else {
		rp->p_rts_flags = NO_MAP;	/* prevent from running */
	}

	/* Code and data segments must be allocated in protected mode. */
	alloc_segments(rp);
  }
Exemplo n.º 5
0
/*===========================================================================*
 *				main                                         *
 *===========================================================================*/
PUBLIC void main()
{
/* Start the ball rolling. */
  struct boot_image *ip;	/* boot image pointer */
  register struct proc *rp;	/* process pointer */
  register struct priv *sp;	/* privilege structure pointer */
  register int i, s;
  // a.out 头部数组的索引.
  int hdrindex;			/* index to array of a.out headers */
  phys_clicks text_base;
  vir_clicks text_clicks, data_clicks;
  // 内核任务栈的基地址(低端)
  reg_t ktsb;			/* kernel task stack base */
  // 用来放置 a.out 头部的一个副本.
  struct exec e_hdr;		/* for a copy of an a.out header */

  /* Initialize the interrupt controller. */
  // 初始化 8259 中断控制器芯片.
  intr_init(1);

  /* Clear the process table. Anounce each slot as empty and set up mappings 
   * for proc_addr() and proc_nr() macros. Do the same for the table with 
   * privilege structures for the system processes. 
   */
  // 初如化进程表与进程指针表.
  // BEG_PROC_ADDR: 进程表地址;
  for (rp = BEG_PROC_ADDR, i = -NR_TASKS; rp < END_PROC_ADDR; ++rp, ++i) {
	  // 将进程表中每一项都设置为空闲.
  	rp->p_rts_flags = SLOT_FREE;		/* initialize free slot */
	// 进程号, i 的初值为 -NR_TASKS, 可见系统任务拥有负的进程号
	rp->p_nr = i;				/* proc number from ptr */
	// 建立进程数组与进程指针数组之间的映射关系
        (pproc_addr + NR_TASKS)[i] = rp;        /* proc ptr from number */
  }
  // 初始化优先级表
  for (sp = BEG_PRIV_ADDR, i = 0; sp < END_PRIV_ADDR; ++sp, ++i) {
	sp->s_proc_nr = NONE;			/* initialize as free */
	sp->s_id = i;				/* priv structure index */
	// 建立特权级表与特权级指针表之间的映射关系
	ppriv_addr[i] = sp;			/* priv ptr from number */
  }

  /* Set up proc table entries for tasks and servers.  The stacks of the
   * kernel tasks are initialized to an array in data space.  The stacks
   * of the servers have been added to the data segment by the monitor, so
   * the stack pointer is set to the end of the data segment.  All the
   * processes are in low memory on the 8086.  On the 386 only the kernel
   * is in low memory, the rest is loaded in extended memory.
   */
  /*
   * 为任务和服务进程设置进程表项. 内核任务的栈被初始化成一个在数据空间中的
   * 数组. 服务进程的栈已经由控制器添加到数据段中, 所有它们的栈指针开始时
   * 指向数据段的末尾. 所有的进程都在 8086 的低内存. 对于 386, 只有内核在
   * 低内存, 剩下的都在扩展内存中.
   */

  /* Task stacks. */
  /* 任务栈 */
  ktsb = (reg_t) t_stack;
 // 为那些包含在系统引导映像文件中的程序分配进程表项.
  for (i=0; i < NR_BOOT_PROCS; ++i) {
	ip = &image[i];				/* process' attributes */
	// 获取进程指针
	rp = proc_addr(ip->proc_nr);		/* get process pointer */
	// 最大调度优先级
	rp->p_max_priority = ip->priority;	/* max scheduling priority */
	// 当前调度优先级
	rp->p_priority = ip->priority;		/* current priority */
	// 时间片原子值
	rp->p_quantum_size = ip->quantum;	/* quantum size in ticks */
	// 剩余时间片
	rp->p_ticks_left = ip->quantum;		/* current credit */
	// 将程序名复制到进程表项中
	strncpy(rp->p_name, ip->proc_name, P_NAME_LEN); /* set process name */
	// 为进程分配一个特权级结构体, 即 从系统特权级表中分配一项
	(void) get_priv(rp, (ip->flags & SYS_PROC));    /* assign structure */
	// 初始化特权级结构体的标志.
	priv(rp)->s_flags = ip->flags;			/* process flags */
	// 初始化特权级结构体的 允许的系统调用陷井
	priv(rp)->s_trap_mask = ip->trap_mask;		/* allowed traps */
	priv(rp)->s_call_mask = ip->call_mask;		/* kernel call mask */
	// 初始化进程的消息发送位图
	priv(rp)->s_ipc_to.chunk[0] = ip->ipc_to;	/* restrict targets */
	// 如果进程是内核任务
	if (iskerneln(proc_nr(rp))) {		/* part of the kernel? */ 
		// 如果进程的栈大小大于 0, 设置进程的栈警戒字, 
		if (ip->stksize > 0) {		/* HARDWARE stack size is 0 */
			// 设置内核任务栈警戒字指针.
			rp->p_priv->s_stack_guard = (reg_t *) ktsb;
			// 指针运算符(->) 要比取值运行符 (*) 的优先级要高.
			// 等价于: 
			// *(rp->p_priv->s_stack_guard) = STACK_GUARD
			// 效果是在栈的最顶端(在低地址)放置一个特殊值,
			// 这个值就是栈警戒字.
			*rp->p_priv->s_stack_guard = STACK_GUARD;
		}
		ktsb += ip->stksize;	/* point to high end of stack */
		// 初始进程的栈指针
		rp->p_reg.sp = ktsb;	/* this task's initial stack ptr */
		// kinfo ???
		// 内核代码的基地址右移 CLICK_SHIFT 位, 赋给 text_base.
		text_base = kinfo.code_base >> CLICK_SHIFT;
					/* processes that are in the kernel */
		// 内核任务使用同一个 a.out 头部信息
		hdrindex = 0;		/* all use the first a.out header */
	} else {
		// 非内核任务, 计算它的 a.out 头部数组索引, 因为 0 号项
		// 留给了内核任务, 所以需 加 1.
		hdrindex = 1 + i-NR_TASKS;	/* servers, drivers, INIT */
	}

	/* The bootstrap loader created an array of the a.out headers at
	 * absolute address 'aout'. Get one element to e_hdr.
	 */
	/*
	 * 引导加载程序会在绝对地址 'aout' 处放置一个 a.out 头部数组.
	 * 从中取一项复制到 e_hdr.
	 */
	phys_copy(aout + hdrindex * A_MINHDR, vir2phys(&e_hdr),
						(phys_bytes) A_MINHDR);
	/* Convert addresses to clicks and build process memory map */
	/* 将地址转换为以 click 为单位, 并建立进程内存映射 */
	// 既然这里要设置 text_base, 那 146 行附近的 
	// text_base = kinfo.code_base >> CLICK_SHIFT;
	// 岂不是多余的??
	// 将 a.out 头部的符号表大小右移 CLICK_SHIFT 位,赋给 text_base.
	text_base = e_hdr.a_syms >> CLICK_SHIFT;
	// 计算程序文本段大小, 以 click 为单位, 上取整.
	text_clicks = (e_hdr.a_text + CLICK_SIZE-1) >> CLICK_SHIFT;
	// 如果 a.out 头部指明它的 I/D 是合并的 ???
	if (!(e_hdr.a_flags & A_SEP)) text_clicks = 0;	   /* common I&D */
	// 计算程序占用的内存量, 以 click 为单位, 上取整.
	data_clicks = (e_hdr.a_total + CLICK_SIZE-1) >> CLICK_SHIFT;
	// 初始化进程的内存映射数据结构
	rp->p_memmap[T].mem_phys = text_base;
	rp->p_memmap[T].mem_len  = text_clicks;
	rp->p_memmap[D].mem_phys = text_base + text_clicks;
	rp->p_memmap[D].mem_len  = data_clicks;
	rp->p_memmap[S].mem_phys = text_base + text_clicks + data_clicks;
	rp->p_memmap[S].mem_vir  = data_clicks;	/* empty - stack is in data */

	/* Set initial register values.  The processor status word for tasks 
	 * is different from that of other processes because tasks can
	 * access I/O; this is not allowed to less-privileged processes 
	 */
	/*
	 * 设置寄存器的初始值. 与其他进程相比, 内核任务的处理器状态字
	 * 稍有不同, 因为内核任务可以访问 I/O; 而对于非特权进来来说, 这是不
	 * 允许的.
	 */
	// 初始化进程的 PC 和 processor status word.
	rp->p_reg.pc = (reg_t) ip->initial_pc;
	rp->p_reg.psw = (iskernelp(rp)) ? INIT_TASK_PSW : INIT_PSW;

	/* Initialize the server stack pointer. Take it down one word
	 * to give crtso.s something to use as "argc".
	 */
	/*
	 * 初始化服务器进程的栈指针. 下移一个字的空间, 使得 crtso.s 有
	 * 空间放置 "argc".
	 */
	if (isusern(proc_nr(rp))) {		/* user-space process? */ 
		rp->p_reg.sp = (rp->p_memmap[S].mem_vir +
				rp->p_memmap[S].mem_len) << CLICK_SHIFT;
		rp->p_reg.sp -= sizeof(reg_t);
	}
	
	/* Set ready. The HARDWARE task is never ready. */
	if (rp->p_nr != HARDWARE) {
		// 如果进程不是 HARDWARE, 清空进程标志, 并加入调度队列.
		rp->p_rts_flags = 0;		/* runnable if no flags */
		lock_enqueue(rp);		/* add to scheduling queues */
	} else {
		// 对于  HARDWARE 任务, 则阻止其运行. ???
		rp->p_rts_flags = NO_MAP;	/* prevent from running */
	}

	/* Code and data segments must be allocated in protected mode. */
	/* 数据与代码段必须在保护模式下分配 */
	alloc_segments(rp);
  }