main.c

一个简单的操作系统minix的核心代码

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				src/kernel/main.c	 	 
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06700	/* This file contains the main program of MINIX.  The routine main()
06701	 * initializes the system and starts the ball rolling by setting up the proc
06702	 * table, interrupt vectors, and scheduling each task to run to initialize
06703	 * itself.
06704	 *
06705	 * The entries into this file are:
06706	 *   main:              MINIX main program
06707	 *   panic:             abort MINIX due to a fatal error
06708	 */
06709	
06710	#include "kernel.h"
06711	#include <signal.h>
06712	#include <unistd.h>
06713	#include <minix/callnr.h>
06714	#include <minix/com.h>
06715	#include "proc.h"
06716	
06717	
06718	/*===========================================================================*
06719	 *                                   main                                    *
06720	 *===========================================================================*/
06721	PUBLIC void main()
06722	{
06723	/* Start the ball rolling. */
06724	
06725	  register struct proc *rp;
06726	  register int t;
06727	  int sizeindex;
06728	  phys_clicks text_base;
06729	  vir_clicks text_clicks;
06730	  vir_clicks data_clicks;
06731	  phys_bytes phys_b;
06732	  reg_t ktsb;                   /* kernel task stack base */
06733	  struct memory *memp;
06734	  struct tasktab *ttp;
06735	
06736	  /* Initialize the interrupt controller. */
06737	  intr_init(1);
06738	
06739	  /* Interpret memory sizes. */
06740	  mem_init();
06741	
06742	  /* Clear the process table.
06743	   * Set up mappings for proc_addr() and proc_number() macros.
06744	   */
06745	  for (rp = BEG_PROC_ADDR, t = -NR_TASKS; rp < END_PROC_ADDR; ++rp, ++t) {
06746	        rp->p_flags = P_SLOT_FREE;
06747	        rp->p_nr = t;           /* proc number from ptr */
06748	        (pproc_addr + NR_TASKS)[t] = rp;        /* proc ptr from number */
06749	  }
06750	
06751	  /* Set up proc table entries for tasks and servers.  The stacks of the
06752	   * kernel tasks are initialized to an array in data space.  The stacks
06753	   * of the servers have been added to the data segment by the monitor, so
06754	   * the stack pointer is set to the end of the data segment.  All the
06755	   * processes are in low memory on the 8086.  On the 386 only the kernel
06756	   * is in low memory, the rest if loaded in extended memory.
06757	   */
06758	
06759	  /* Task stacks. */
06760	  ktsb = (reg_t) t_stack;
06761	
06762	  for (t = -NR_TASKS; t <= LOW_USER; ++t) {
06763	        rp = proc_addr(t);                      /* t's process slot */
06764	        ttp = &tasktab[t + NR_TASKS];           /* t's task attributes */
06765	        strcpy(rp->p_name, ttp->name);
06766	        if (t < 0) {
06767	                if (ttp->stksize > 0) {
06768	                        rp->p_stguard = (reg_t *) ktsb;
06769	                        *rp->p_stguard = STACK_GUARD;
06770	                }
06771	                ktsb += ttp->stksize;
06772	                rp->p_reg.sp = ktsb;
06773	                text_base = code_base >> CLICK_SHIFT;
06774	                                        /* tasks are all in the kernel */
06775	                sizeindex = 0;          /* and use the full kernel sizes */
06776	                memp = &mem[0];         /* remove from this memory chunk */
06777	        } else {
06778	                sizeindex = 2 * t + 2;  /* MM, FS, INIT have their own sizes */
06779	        }
06780	        rp->p_reg.pc = (reg_t) ttp->initial_pc;
06781	        rp->p_reg.psw = istaskp(rp) ? INIT_TASK_PSW : INIT_PSW;
06782	
06783	        text_clicks = sizes[sizeindex];
06784	        data_clicks = sizes[sizeindex + 1];
06785	        rp->p_map[T].mem_phys = text_base;
06786	        rp->p_map[T].mem_len  = text_clicks;
06787	        rp->p_map[D].mem_phys = text_base + text_clicks;
06788	        rp->p_map[D].mem_len  = data_clicks;
06789	        rp->p_map[S].mem_phys = text_base + text_clicks + data_clicks;
06790	        rp->p_map[S].mem_vir  = data_clicks;    /* empty - stack is in data */
06791	        text_base += text_clicks + data_clicks; /* ready for next, if server */
06792	        memp->size -= (text_base - memp->base);
06793	        memp->base = text_base;                 /* memory no longer free */
06794	
06795	        if (t >= 0) {
06796	                /* Initialize the server stack pointer.  Take it down one word
06797	                 * to give crtso.s something to use as "argc".
06798	                 */
06799	                rp->p_reg.sp = (rp->p_map[S].mem_vir +
06800	                                rp->p_map[S].mem_len) << CLICK_SHIFT;
06801	                rp->p_reg.sp -= sizeof(reg_t);
06802	        }
06803	
06804	#if _WORD_SIZE == 4
06805	        /* Servers are loaded in extended memory if in 386 mode. */
06806	        if (t < 0) {
06807	                memp = &mem[1];
06808	                text_base = 0x100000 >> CLICK_SHIFT;
06809	        }
06810	#endif
06811	        if (!isidlehardware(t)) lock_ready(rp); /* IDLE, HARDWARE neveready */
06812	        rp->p_flags = 0;
06813	
06814	        alloc_segments(rp);
06815	  }
06816	
06817	  proc[NR_TASKS+INIT_PROC_NR].p_pid = 1;/* INIT of course has pid 1 */
06818	  bill_ptr = proc_addr(IDLE);           /* it has to point somewhere */
06819	  lock_pick_proc();
06820	
06821	  /* Now go to the assembly code to start running the current process. */
06822	  restart();
06823	}
	
	
06826	/*===========================================================================*
06827	 *                                   panic                                   *
06828	 *===========================================================================*/
06829	PUBLIC void panic(s,n)
06830	_CONST char *s;
06831	int n;
06832	{
06833	/* The system has run aground of a fatal error.  Terminate execution.
06834	 * If the panic originated in MM or FS, the string will be empty and the
06835	 * file system already syncked.  If the panic originates in the kernel, we are
06836	 * kind of stuck.
06837	 */
06838	
06839	  if (*s != 0) {
06840	        printf("\nKernel panic: %s",s);
06841	        if (n != NO_NUM) printf(" %d", n);
06842	        printf("\n");
06843	  }
06844	  wreboot(RBT_PANIC);
06845	}