main.c

Simple Operating Systems （简称SOS）是一个可以运行在X86平台上（包括QEMU

      
      /* Lend the CPU to some other thread */
      sos_thread_yield();
    }
}


/* ======================================================================
 * Kernel thread showing some CPU usage statistics on the console every 1s
 */
static void stat_thread()
{
  while (1)
    {
      sos_ui32_t flags;
      sos_ui32_t load1, load5, load15;
      char str1[11], str5[11], str15[11];
      struct sos_time t;
      t.sec = 1;
      t.nanosec = 0;

      sos_thread_sleep(& t);

      sos_disable_IRQs(flags);

      /* The IDLE task is EXcluded in the following computation */
      sos_load_get_sload(&load1, &load5, &load15);
      sos_load_to_string(str1, load1);
      sos_load_to_string(str5, load5);
      sos_load_to_string(str15, load15);
      sos_x86_videomem_printf(16, 34,
			      SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
			      "Kernel (- Idle): %s %s %s    ",
			      str1, str5, str15);

      sos_load_get_uload(&load1, &load5, &load15);
      sos_load_to_string(str1, load1);
      sos_load_to_string(str5, load5);
      sos_load_to_string(str15, load15);
      sos_x86_videomem_printf(17, 34,
			      SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
			      "User: %s %s %s        ",
			      str1, str5, str15);

      sos_load_get_uratio(&load1, &load5, &load15);
      sos_load_to_string(str1, load1);
      sos_load_to_string(str5, load5);
      sos_load_to_string(str15, load15);
      sos_x86_videomem_printf(18, 34,
			      SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
			      "User CPU %%: %s %s %s        ",
			      str1, str5, str15);

      /* The IDLE task is INcluded in the following computation */
      sos_load_get_sratio(&load1, &load5, &load15);
      sos_load_to_string(str1, load1);
      sos_load_to_string(str5, load5);
      sos_load_to_string(str15, load15);
      sos_x86_videomem_printf(19, 34,
			      SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
			      "Kernel CPU %% (+ Idle): %s %s %s    ",
			      str1, str5, str15);
      sos_restore_IRQs(flags);
    }
}


/* ======================================================================
 * The C entry point of our operating system
 */
void sos_main(unsigned long magic, unsigned long addr)
{
  unsigned i;
  sos_paddr_t sos_kernel_core_base_paddr, sos_kernel_core_top_paddr;
  struct sos_time tick_resolution;

  /* Grub sends us a structure, called multiboot_info_t with a lot of
     precious informations about the system, see the multiboot
     documentation for more information. */
  multiboot_info_t *mbi;
  mbi = (multiboot_info_t *) addr;

  /* Setup bochs and console, and clear the console */
  sos_bochs_setup();

  sos_x86_videomem_setup();
  sos_x86_videomem_cls(SOS_X86_VIDEO_BG_BLUE);

  /* Greetings from SOS */
  if (magic == MULTIBOOT_BOOTLOADER_MAGIC)
    /* Loaded with Grub */
    sos_x86_videomem_printf(1, 0,
			    SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
			    "Welcome From GRUB to %s%c RAM is %dMB (upper mem = 0x%x kB)",
			    "SOS article 7", ',',
			    (unsigned)(mbi->mem_upper >> 10) + 1,
			    (unsigned)mbi->mem_upper);
  else
    /* Not loaded with grub */
    sos_x86_videomem_printf(1, 0,
			    SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
			    "Welcome to SOS article 7");

  sos_bochs_putstring("Message in a bochs: This is SOS article 7.\n");

  /* Setup CPU segmentation and IRQ subsystem */
  sos_gdt_subsystem_setup();
  sos_idt_subsystem_setup();

  /* Setup SOS IRQs and exceptions subsystem */
  sos_exception_subsystem_setup();
  sos_irq_subsystem_setup();

  /* Configure the timer so as to raise the IRQ0 at a 100Hz rate */
  sos_i8254_set_frequency(100);

  /* Setup the kernel time subsystem to get prepared to take the timer
     ticks into account */
  tick_resolution = (struct sos_time) { .sec=0, .nanosec=10000000UL };
  sos_time_subsysem_setup(& tick_resolution);

  /* We need a multiboot-compliant boot loader to get the size of the RAM */
  if (magic != MULTIBOOT_BOOTLOADER_MAGIC)
    {
      sos_x86_videomem_putstring(20, 0,
				 SOS_X86_VIDEO_FG_LTRED
				   | SOS_X86_VIDEO_BG_BLUE
				   | SOS_X86_VIDEO_FG_BLINKING,
				 "I'm not loaded with Grub !");
      /* STOP ! */
      for (;;)
	continue;
    }

  /*
   * Some interrupt handlers
   */

  /* Binding some HW interrupts and exceptions to software routines */
  sos_irq_set_routine(SOS_IRQ_TIMER,
		      clk_it);

  /*
   * Setup physical memory management
   */

  /* Multiboot says: "The value returned for upper memory is maximally
     the address of the first upper memory hole minus 1 megabyte.". It
     also adds: "It is not guaranteed to be this value." aka "YMMV" ;) */
  sos_physmem_subsystem_setup((mbi->mem_upper<<10) + (1<<20),
			      & sos_kernel_core_base_paddr,
			      & sos_kernel_core_top_paddr);
  
  /*
   * Switch to paged-memory mode
   */

  /* Disabling interrupts should seem more correct, but it's not really
     necessary at this stage */
  SOS_ASSERT_FATAL(SOS_OK ==
		   sos_paging_subsystem_setup(sos_kernel_core_base_paddr,
					      sos_kernel_core_top_paddr));
  
  /* Bind the page fault exception */
  sos_exception_set_routine(SOS_EXCEPT_PAGE_FAULT,
			    pgflt_ex);

  /*
   * Setup kernel virtual memory allocator
   */

  if (sos_kmem_vmm_subsystem_setup(sos_kernel_core_base_paddr,
				   sos_kernel_core_top_paddr,
				   bootstrap_stack_bottom,
				   bootstrap_stack_bottom
				   + bootstrap_stack_size))
    sos_bochs_printf("Could not setup the Kernel virtual space allocator\n");

  if (sos_kmalloc_subsystem_setup())
    sos_bochs_printf("Could not setup the Kmalloc subsystem\n");

  /*
   * Initialize the MMU context subsystem
   */
  sos_mm_context_subsystem_setup();

  /*
   * Initialize the CPU context subsystem
   */
  sos_cpu_context_subsystem_setup();

  /*
   * Bind the syscall handler to its software interrupt handler
   */
  sos_swintr_subsystem_setup();


  /*
   * Initialize the Kernel thread and scheduler subsystems
   */
  
  /* Initialize kernel thread subsystem */
  sos_thread_subsystem_setup(bootstrap_stack_bottom,
			     bootstrap_stack_size);

  /* Initialize the scheduler */
  sos_sched_subsystem_setup();

  /* Declare the IDLE thread */
  SOS_ASSERT_FATAL(sos_create_kernel_thread("idle", idle_thread, NULL,
   					    SOS_SCHED_PRIO_TS_LOWEST) != NULL);

  /* Prepare the stats subsystem */
  sos_load_subsystem_setup();

  /* Declare a thread that prints some stats */
  SOS_ASSERT_FATAL(sos_create_kernel_thread("stat_thread", stat_thread,
					    NULL,
					    SOS_SCHED_PRIO_TS_LOWEST) != NULL);


  /*
   * Initialize process stuff
   */
  sos_process_subsystem_setup();


  /* Enabling the HW interrupts here, this will make the timer HW
     interrupt call the scheduler */
  asm volatile ("sti\n");

  /* Run some tests involving USER processes and threads */
  extern void test_art7();
  test_art7();

  /* Now run some Kernel threads just for fun ! */
  extern void MouseSim();
  MouseSim();
  test_thread();

  /*
   * We can safely exit from this function now, for there is already
   * an idle Kernel thread ready to make the CPU busy working...
   *
   * However, we must EXPLICITELY call sos_thread_exit() because a
   * simple "return" will return nowhere ! Actually this first thread
   * was initialized by the Grub bootstrap stage, at a time when the
   * word "thread" did not exist. This means that the stack was not
   * setup in order for a return here to call sos_thread_exit()
   * automagically. Hence we must call it manually. This is the ONLY
   * kernel thread where we must do this manually.
   */
  sos_bochs_printf("Bye from primary thread !\n");
  sos_thread_exit();
  SOS_FATAL_ERROR("No trespassing !");
}