text: /*
   *  linux/init/main.c
   *
   *  Copyright (C) 1991, 1992  Linus Torvalds
   *
   *  GK 2/5/95  -  Changed to support mounting root fs via NFS
   *  Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
   *  Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
   *  Simplified starting of init:  Michael A. Griffith <grif@acm.org> 
   */
  
  #define __KERNEL_SYSCALLS__
  
  #include <linux/config.h>
  #include <linux/proc_fs.h>
  #include <linux/devfs_fs_kernel.h>
  #include <linux/unistd.h>
  #include <linux/string.h>
  #include <linux/ctype.h>
  #include <linux/delay.h>
  #include <linux/utsname.h>
  #include <linux/ioport.h>
  #include <linux/init.h>
  #include <linux/smp_lock.h>
  #include <linux/blk.h>
  #include <linux/hdreg.h>
  #include <linux/iobuf.h>
  #include <linux/bootmem.h>
  #include <linux/file.h>
  #include <linux/tty.h>
  
  #include <asm/io.h>
  #include <asm/bugs.h>
  
  #if defined(CONFIG_ARCH_S390)
  #include <asm/s390mach.h>
  #include <asm/ccwcache.h>
  #endif
  
  #ifdef CONFIG_ACPI
  #include <linux/acpi.h>
  #endif
  
  #ifdef CONFIG_PCI
  #include <linux/pci.h>
  #endif
  
  #ifdef CONFIG_DIO
  #include <linux/dio.h>
  #endif
  
  #ifdef CONFIG_ZORRO
  #include <linux/zorro.h>
  #endif
  
  #ifdef CONFIG_MTRR
  #  include <asm/mtrr.h>
  #endif
  
  #ifdef CONFIG_NUBUS
  #include <linux/nubus.h>
  #endif
  
  #ifdef CONFIG_ISAPNP
  #include <linux/isapnp.h>
  #endif
  
  #ifdef CONFIG_IRDA
  extern int irda_proto_init(void);
  extern int irda_device_init(void);
  #endif
  
  #ifdef CONFIG_X86_LOCAL_APIC
  #include <asm/smp.h>
  #endif
  
  /*
   * Versions of gcc older than that listed below may actually compile
   * and link okay, but the end product can have subtle run time bugs.
   * To avoid associated bogus bug reports, we flatly refuse to compile
   * with a gcc that is known to be too old from the very beginning.
   */
  #if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 91)
  #error Sorry, your GCC is too old. It builds incorrect kernels.
  #endif
  
  extern char _stext, _etext;
  extern char *linux_banner;
  
  static int init(void *);
  
  extern void init_IRQ(void);
  extern void init_modules(void);
  extern void sock_init(void);
  extern void fork_init(unsigned long);
  extern void mca_init(void);
  extern void sbus_init(void);
  extern void ppc_init(void);
  extern void sysctl_init(void);
  extern void signals_init(void);
  extern int init_pcmcia_ds(void);
  
  extern void free_initmem(void);
  #ifdef  CONFIG_ACPI_BUS
  extern void acpi_early_init(void);
  #else
  static inline void acpi_early_init(void) { }
  #endif
  
  #ifdef CONFIG_TC
  extern void tc_init(void);
  #endif
  
  extern void ecard_init(void);
  
  #if defined(CONFIG_SYSVIPC)
  extern void ipc_init(void);
  #endif
  
  /*
   * Boot command-line arguments
   */
  #define MAX_INIT_ARGS 8
  #define MAX_INIT_ENVS 8
  
  extern void time_init(void);
  extern void softirq_init(void);
  
  int rows, cols;
  
  char *execute_command;
  
  static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
  char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
  
  static int __init profile_setup(char *str)
  {
      int par;
      if (get_option(&str,&par)) prof_shift = par;
  	return 1;
  }
  
  __setup("profile=", profile_setup);
  
  static int __init checksetup(char *line)
  {
  	struct kernel_param *p;
  
  	p = &__setup_start;
  	do {
  		int n = strlen(p->str);
  		if (!strncmp(line,p->str,n)) {
  			if (p->setup_func(line+n))
  				return 1;
  		}
  		p++;
  	} while (p < &__setup_end);
  	return 0;
  }
  
  /* this should be approx 2 Bo*oMips to start (note initial shift), and will
     still work even if initially too large, it will just take slightly longer */
  unsigned long loops_per_jiffy = (1<<12);
  
  /* This is the number of bits of precision for the loops_per_jiffy.  Each
     bit takes on average 1.5/HZ seconds.  This (like the original) is a little
     better than 1% */
  #define LPS_PREC 8
  
  void __init calibrate_delay(void)
  {
  	unsigned long ticks, loopbit;
  	int lps_precision = LPS_PREC;
  
  	loops_per_jiffy = (1<<12);
  
  	printk("Calibrating delay loop... ");
  	while (loops_per_jiffy <<= 1) {
  		/* wait for "start of" clock tick */
  		ticks = jiffies;
  		while (ticks == jiffies)
  			/* nothing */;
  		/* Go .. */
  		ticks = jiffies;
  		__delay(loops_per_jiffy);
  		ticks = jiffies - ticks;
  		if (ticks)
  			break;
  	}
  
  /* Do a binary approximation to get loops_per_jiffy set to equal one clock
     (up to lps_precision bits) */
  	loops_per_jiffy >>= 1;
  	loopbit = loops_per_jiffy;
  	while ( lps_precision-- && (loopbit >>= 1) ) {
  		loops_per_jiffy |= loopbit;
  		ticks = jiffies;
  		while (ticks == jiffies);
  		ticks = jiffies;
  		__delay(loops_per_jiffy);
  		if (jiffies != ticks)	/* longer than 1 tick */
  			loops_per_jiffy &= ~loopbit;
  	}
  
  /* Round the value and print it */	
  	printk("%lu.%02lu BogoMIPS\n",
  		loops_per_jiffy/(500000/HZ),
  		(loops_per_jiffy/(5000/HZ)) % 100);
  }
  
  static int __init debug_kernel(char *str)
  {
  	if (*str)
  		return 0;
  	console_loglevel = 10;
  	return 1;
  }
  
  static int __init quiet_kernel(char *str)
  {
  	if (*str)
  		return 0;
  	console_loglevel = 4;
  	return 1;
  }
  
  __setup("debug", debug_kernel);
  __setup("quiet", quiet_kernel);
  
  /*
   * This is a simple kernel command line parsing function: it parses
   * the command line, and fills in the arguments/environment to init
   * as appropriate. Any cmd-line option is taken to be an environment
   * variable if it contains the character '='.
   *
   * This routine also checks for options meant for the kernel.
   * These options are not given to init - they are for internal kernel use only.
   */
  static void __init parse_options(char *line)
  {
  	char *next,*quote;
  	int args, envs;
  
  	if (!*line)
  		return;
  	args = 0;
  	envs = 1;	/* TERM is set to 'linux' by default */
  	next = line;
  	while ((line = next) != NULL) {
                  quote = strchr(line,'"');
                  next = strchr(line, ' ');
                  while (next != NULL && quote != NULL && quote < next) {
                          /* we found a left quote before the next blank
                           * now we have to find the matching right quote
                           */
                          next = strchr(quote+1, '"');
                          if (next != NULL) {
                                  quote = strchr(next+1, '"');
                                  next = strchr(next+1, ' ');
                          }
                  }
                  if (next != NULL)
                          *next++ = 0;
  		if (!strncmp(line,"init=",5)) {
  			line += 5;
  			execute_command = line;
  			/* In case LILO is going to boot us with default command line,
  			 * it prepends "auto" before the whole cmdline which makes
  			 * the shell think it should execute a script with such name.
  			 * So we ignore all arguments entered _before_ init=... [MJ]
  			 */
  			args = 0;
  			continue;
  		}
  		if (checksetup(line))
  			continue;
  		
  		/*
  		 * Then check if it's an environment variable or
  		 * an option.
  		 */
  		if (strchr(line,'=')) {
  			if (envs >= MAX_INIT_ENVS)
  				break;
  			envp_init[++envs] = line;
  		} else {
  			if (args >= MAX_INIT_ARGS)
  				break;
  			if (*line)
  				argv_init[++args] = line;
  		}
  	}
  	argv_init[args+1] = NULL;
  	envp_init[envs+1] = NULL;
  }
  
  
  extern void setup_arch(char **);
  
  unsigned long wait_init_idle;
  
  #ifndef CONFIG_SMP
  
  #ifdef CONFIG_X86_LOCAL_APIC
  static void __init smp_init(void)
  {
  	APIC_init_uniprocessor();
  }
  #else
  #define smp_init()	do { } while (0)
  #endif
  
  #else
  
  
  /* Called by boot processor to activate the rest. */
  static void __init smp_init(void)
  {
  	/* Get other processors into their bootup holding patterns. */
  	smp_boot_cpus();
  	wait_init_idle = cpu_online_map;
  	clear_bit(current->processor, &wait_init_idle); /* Don't wait on me! */
  
  	smp_threads_ready=1;
  	smp_commence();
  
  	/* Wait for the other cpus to set up their idle processes */
  	printk("Waiting on wait_init_idle (map = 0x%lx)\n", wait_init_idle);
  	while (wait_init_idle) {
  		cpu_relax();
  		barrier();
  	}
  	printk("All processors have done init_idle\n");
  }
  
  #endif
  
  /*
   * We need to finalize in a non-__init function or else race conditions
   * between the root thread and the init thread may cause start_kernel to
   * be reaped by free_initmem before the root thread has proceeded to
   * cpu_idle.
   */
  
  static void rest_init(void)
  {
  	kernel_thread(init, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGNAL);
  	unlock_kernel();
  	current->need_resched = 1;
   	cpu_idle();
  } 
  
  /*
   *	Activate the first processor.
   */
  
  asmlinkage void __init start_kernel(void)
  {
  	char * command_line;
  	extern char saved_command_line[];
  /*
   * Interrupts are still disabled. Do necessary setups, then
   * enable them
   */
  	lock_kernel();
  	printk(linux_banner);
  	setup_arch(&command_line);
  	printk("Kernel command line: %s\n", saved_command_line);
  	parse_options(command_line);
  	trap_init();
  	init_IRQ();
  	sched_init();
  	softirq_init();
  	time_init();
  
  	/*
  	 * HACK ALERT! This is early. We're enabling the console before
  	 * we've done PCI setups etc, and console_init() must be aware of
  	 * this. But we do want output early, in case something goes wrong.
  	 */
  	console_init();
  #ifdef CONFIG_MODULES
  	init_modules();
  #endif
  	if (prof_shift) {
  		unsigned int size;
  		/* only text is profiled */
  		prof_len = (unsigned long) &_etext - (unsigned long) &_stext;
  		prof_len >>= prof_shift;
  		
  		size = prof_len * sizeof(unsigned int) + PAGE_SIZE-1;
  		prof_buffer = (unsigned int *) alloc_bootmem(size);
  	}
  
  	kmem_cache_init();
  	sti();
  	calibrate_delay();
  #ifdef CONFIG_BLK_DEV_INITRD
  	if (initrd_start && !initrd_below_start_ok &&
  			initrd_start < min_low_pfn << PAGE_SHIFT) {
  		printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
  		    "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
  		initrd_start = 0;
  	}
  #endif
  	mem_init();
  	kmem_cache_sizes_init();
  	pgtable_cache_init();
  
  	/*
  	 * For architectures that have highmem, num_mappedpages represents
  	 * the amount of memory the kernel can use.  For other architectures
  	 * it's the same as the total pages.  We need both numbers because
  	 * some subsystems need to initialize based on how much memory the
  	 * kernel can use.
  	 */
  	if (num_mappedpages == 0)
  		num_mappedpages = num_physpages;
    
  	fork_init(num_mappedpages);
  	proc_caches_init();
  	vfs_caches_init(num_physpages);
  	buffer_init(num_physpages);
  	page_cache_init(num_physpages);
  #if defined(CONFIG_ARCH_S390)
  	ccwcache_init();
  #endif
  	signals_init();
  #ifdef CONFIG_PROC_FS
  	proc_root_init();
  #endif
  	check_bugs();
  	acpi_early_init(); /* before LAPIC and SMP init */
  	printk("POSIX conformance testing by UNIFIX\n");
  
  	/* 
  	 *	We count on the initial thread going ok 
  	 *	Like idlers init is an unlocked kernel thread, which will
  	 *	make syscalls (and thus be locked).
  	 */
  	smp_init();
  #if defined(CONFIG_SYSVIPC)
  	ipc_init();
  #endif
  	rest_init();
  }
  
  struct task_struct *child_reaper = &init_task;
  
  static void __init do_initcalls(void)
  {
  	initcall_t *call;
  
  	call = &__initcall_start;
  	do {
  		(*call)();
  		call++;
  	} while (call < &__initcall_end);
  
  	/* Make sure there is no pending stuff from the initcall sequence */
  	flush_scheduled_tasks();
  }
  
  /*
   * Ok, the machine is now initialized. None of the devices
   * have been touched yet, but the CPU subsystem is up and
   * running, and memory and process management works.
   *
   * Now we can finally start doing some real work..
   */
  static void __init do_basic_setup(void)
  {
  
  	/*
  	 * Tell the world that we're going to be the grim
  	 * reaper of innocent orphaned children.
  	 *
  	 * We don't want people to have to make incorrect
  	 * assumptions about where in the task array this
  	 * can be found.
  	 */
  	child_reaper = current;
  
  #if defined(CONFIG_MTRR)	/* Do this after SMP initialization */
  /*
   * We should probably create some architecture-dependent "fixup after
   * everything is up" style function where this would belong better
   * than in init/main.c..
   */
  	mtrr_init();
  #endif
  
  #ifdef CONFIG_SYSCTL
  	sysctl_init();
  #endif
  
  	/*
  	 * Ok, at this point all CPU's should be initialized, so
  	 * we can start looking into devices..
  	 */
  #if defined(CONFIG_ARCH_S390)
  	s390_init_machine_check();
  #endif
  #ifdef CONFIG_ACPI_INTERPRETER
  	acpi_init();
  #endif
  #ifdef CONFIG_PCI
  	pci_init();
  #endif
  #ifdef CONFIG_SBUS
  	sbus_init();
  #endif
  #if defined(CONFIG_PPC)
  	ppc_init();
  #endif
  #ifdef CONFIG_MCA
  	mca_init();
  #endif
  #ifdef CONFIG_ARCH_ACORN
  	ecard_init();
  #endif
  #ifdef CONFIG_ZORRO
  	zorro_init();
  #endif
  #ifdef CONFIG_DIO
  	dio_init();
  #endif
  #ifdef CONFIG_NUBUS
  	nubus_init();
  #endif
  #ifdef CONFIG_ISAPNP
  	isapnp_init();
  #endif
  #ifdef CONFIG_TC
  	tc_init();
  #endif
  
  	/* Networking initialization needs a process context */ 
  	sock_init();
  
  	start_context_thread();
  	do_initcalls();
  
  #ifdef CONFIG_IRDA
  	irda_proto_init();
  	irda_device_init(); /* Must be done after protocol initialization */
  #endif
  #ifdef CONFIG_PCMCIA
  	init_pcmcia_ds();		/* Do this last */
  #endif
  }
  
  static void run_init_process(char *init_filename)
  {
  	argv_init[0] = init_filename;
  	execve(init_filename, argv_init, envp_init);
  }
  
  extern void prepare_namespace(void);
  
  static int init(void * unused)
  {
  	struct files_struct *files;
  	lock_kernel();
  	do_basic_setup();
  
  	prepare_namespace();
  
  	/*
  	 * Ok, we have completed the initial bootup, and
  	 * we're essentially up and running. Get rid of the
  	 * initmem segments and start the user-mode stuff..
  	 */
  	free_initmem();
  	unlock_kernel();
  	
  	/*
  	 * Right now we are a thread sharing with a ton of kernel
  	 * stuff. We don't want to end up in user space in that state
  	 */
  	 
  	files = current->files;
  	if(unshare_files())
  		panic("unshare");
  	put_files_struct(files);
  	
  	if (open("/dev/console", O_RDWR, 0) < 0)
  		printk("Warning: unable to open an initial console.\n");
  
  	(void) dup(0);
  	(void) dup(0);
  	
  	/*
  	 * We try each of these until one succeeds.
  	 *
  	 * The Bourne shell can be used instead of init if we are 
  	 * trying to recover a really broken machine.
  	 */
  
  	if (execute_command)
  		run_init_process(execute_command);
  
  	run_init_process("/sbin/init");
  	run_init_process("/etc/init");
  	run_init_process("/bin/init");
  	run_init_process("/bin/sh");
  
  	panic("No init found.  Try passing init= option to kernel.");
  }
  