/*
   *  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/types.h>
  #include <linux/module.h>
  #include <linux/proc_fs.h>

  #include <linux/kernel.h>
  #include <linux/syscalls.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/initrd.h>
  #include <linux/hdreg.h>
  #include <linux/bootmem.h>
  #include <linux/tty.h>
  #include <linux/gfp.h>
  #include <linux/percpu.h>
  #include <linux/kmod.h>
  #include <linux/kernel_stat.h>
  #include <linux/security.h>
  #include <linux/workqueue.h>
  #include <linux/profile.h>
  #include <linux/rcupdate.h>
  #include <linux/moduleparam.h>
  #include <linux/kallsyms.h>
  #include <linux/writeback.h>
  #include <linux/cpu.h>
  #include <linux/cpuset.h>
  #include <linux/efi.h>

  #include <linux/taskstats_kern.h>

  #include <linux/delayacct.h>

  #include <linux/unistd.h>
  #include <linux/rmap.h>
  #include <linux/mempolicy.h>
  #include <linux/key.h>

  #include <linux/unwind.h>

  #include <linux/buffer_head.h>

  #include <linux/debug_locks.h>

  #include <linux/lockdep.h>

  
  #include <asm/io.h>
  #include <asm/bugs.h>
  #include <asm/setup.h>

  #include <asm/sections.h>

  #include <asm/cacheflush.h>

  #ifdef CONFIG_X86_LOCAL_APIC
  #include <asm/smp.h>
  #endif
  
  /*

   * This is one of the first .c files built. Error out early if we have compiler
   * trouble.
   *
   * 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__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 2)

  #error Sorry, your GCC is too old. It builds incorrect kernels.
  #endif
  
  static int init(void *);
  
  extern void init_IRQ(void);

  extern void fork_init(unsigned long);
  extern void mca_init(void);
  extern void sbus_init(void);
  extern void sysctl_init(void);
  extern void signals_init(void);

  extern void pidhash_init(void);
  extern void pidmap_init(void);
  extern void prio_tree_init(void);
  extern void radix_tree_init(void);
  extern void free_initmem(void);
  extern void populate_rootfs(void);
  extern void driver_init(void);
  extern void prepare_namespace(void);
  #ifdef	CONFIG_ACPI
  extern void acpi_early_init(void);
  #else
  static inline void acpi_early_init(void) { }
  #endif

  #ifndef CONFIG_DEBUG_RODATA
  static inline void mark_rodata_ro(void) { }
  #endif

  
  #ifdef CONFIG_TC
  extern void tc_init(void);
  #endif
  
  enum system_states system_state;
  EXPORT_SYMBOL(system_state);
  
  /*
   * Boot command-line arguments
   */
  #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
  #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
  
  extern void time_init(void);
  /* Default late time init is NULL. archs can override this later. */
  void (*late_time_init)(void);
  extern void softirq_init(void);
  
  /* Untouched command line (eg. for /proc) saved by arch-specific code. */
  char saved_command_line[COMMAND_LINE_SIZE];
  
  static char *execute_command;

  static char *ramdisk_execute_command;

  
  /* Setup configured maximum number of CPUs to activate */
  static unsigned int max_cpus = NR_CPUS;
  
  /*
   * Setup routine for controlling SMP activation
   *
   * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
   * activation entirely (the MPS table probe still happens, though).
   *
   * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
   * greater than 0, limits the maximum number of CPUs activated in
   * SMP mode to <NUM>.
   */
  static int __init nosmp(char *str)
  {
  	max_cpus = 0;
  	return 1;
  }
  
  __setup("nosmp", nosmp);
  
  static int __init maxcpus(char *str)
  {
  	get_option(&str, &max_cpus);
  	return 1;
  }
  
  __setup("maxcpus=", maxcpus);
  
  static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
  char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
  static const char *panic_later, *panic_param;
  
  extern struct obs_kernel_param __setup_start[], __setup_end[];
  
  static int __init obsolete_checksetup(char *line)
  {
  	struct obs_kernel_param *p;
  
  	p = __setup_start;
  	do {
  		int n = strlen(p->str);
  		if (!strncmp(line, p->str, n)) {
  			if (p->early) {
  				/* Already done in parse_early_param?  (Needs
  				 * exact match on param part) */
  				if (line[n] == '\0' || line[n] == '=')
  					return 1;
  			} else if (!p->setup_func) {
  				printk(KERN_WARNING "Parameter %s is obsolete,"
  				       " ignored
  ", p->str);
  				return 1;
  			} else 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);
  
  EXPORT_SYMBOL(loops_per_jiffy);
  
  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);
  
  static int __init loglevel(char *str)
  {
  	get_option(&str, &console_loglevel);
  	return 1;
  }
  
  __setup("loglevel=", loglevel);
  
  /*
   * Unknown boot options get handed to init, unless they look like
   * failed parameters
   */
  static int __init unknown_bootoption(char *param, char *val)
  {
  	/* Change NUL term back to "=", to make "param" the whole string. */
  	if (val) {
  		/* param=val or param="val"? */
  		if (val == param+strlen(param)+1)
  			val[-1] = '=';
  		else if (val == param+strlen(param)+2) {
  			val[-2] = '=';
  			memmove(val-1, val, strlen(val)+1);
  			val--;
  		} else
  			BUG();
  	}
  
  	/* Handle obsolete-style parameters */
  	if (obsolete_checksetup(param))
  		return 0;
  
  	/*
  	 * Preemptive maintenance for "why didn't my mispelled command
  	 * line work?"
  	 */
  	if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
  		printk(KERN_ERR "Unknown boot option `%s': ignoring
  ", param);
  		return 0;
  	}
  
  	if (panic_later)
  		return 0;
  
  	if (val) {
  		/* Environment option */
  		unsigned int i;
  		for (i = 0; envp_init[i]; i++) {
  			if (i == MAX_INIT_ENVS) {
  				panic_later = "Too many boot env vars at `%s'";
  				panic_param = param;
  			}
  			if (!strncmp(param, envp_init[i], val - param))
  				break;
  		}
  		envp_init[i] = param;
  	} else {
  		/* Command line option */
  		unsigned int i;
  		for (i = 0; argv_init[i]; i++) {
  			if (i == MAX_INIT_ARGS) {
  				panic_later = "Too many boot init vars at `%s'";
  				panic_param = param;
  			}
  		}
  		argv_init[i] = param;
  	}
  	return 0;
  }
  
  static int __init init_setup(char *str)
  {
  	unsigned int i;
  
  	execute_command = str;
  	/*
  	 * 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]
  	 */
  	for (i = 1; i < MAX_INIT_ARGS; i++)
  		argv_init[i] = NULL;
  	return 1;
  }
  __setup("init=", init_setup);

  static int __init rdinit_setup(char *str)
  {
  	unsigned int i;
  
  	ramdisk_execute_command = str;
  	/* See "auto" comment in init_setup */
  	for (i = 1; i < MAX_INIT_ARGS; i++)
  		argv_init[i] = NULL;
  	return 1;
  }
  __setup("rdinit=", rdinit_setup);

  #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
  
  static inline void setup_per_cpu_areas(void) { }
  static inline void smp_prepare_cpus(unsigned int maxcpus) { }
  
  #else
  
  #ifdef __GENERIC_PER_CPU

  unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;

  
  EXPORT_SYMBOL(__per_cpu_offset);
  
  static void __init setup_per_cpu_areas(void)
  {
  	unsigned long size, i;
  	char *ptr;

  	unsigned long nr_possible_cpus = num_possible_cpus();

  
  	/* Copy section for each CPU (we discard the original) */
  	size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
  #ifdef CONFIG_MODULES
  	if (size < PERCPU_ENOUGH_ROOM)
  		size = PERCPU_ENOUGH_ROOM;
  #endif

  	ptr = alloc_bootmem(size * nr_possible_cpus);

  	for_each_possible_cpu(i) {

  		__per_cpu_offset[i] = ptr - __per_cpu_start;
  		memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);

  		ptr += size;

  	}
  }
  #endif /* !__GENERIC_PER_CPU */
  
  /* Called by boot processor to activate the rest. */
  static void __init smp_init(void)
  {
  	unsigned int i;
  
  	/* FIXME: This should be done in userspace --RR */
  	for_each_present_cpu(i) {
  		if (num_online_cpus() >= max_cpus)
  			break;
  		if (!cpu_online(i))
  			cpu_up(i);
  	}
  
  	/* Any cleanup work */
  	printk(KERN_INFO "Brought up %ld CPUs
  ", (long)num_online_cpus());
  	smp_cpus_done(max_cpus);
  #if 0
  	/* Get other processors into their bootup holding patterns. */
  
  	smp_commence();
  #endif
  }
  
  #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.
   *
   * gcc-3.4 accidentally inlines this function, so use noinline.
   */
  
  static void noinline rest_init(void)
  	__releases(kernel_lock)
  {
  	kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
  	numa_default_policy();
  	unlock_kernel();

  
  	/*
  	 * The boot idle thread must execute schedule()
  	 * at least one to get things moving:
  	 */

  	preempt_enable_no_resched();

  	schedule();

  	preempt_disable();

  	/* Call into cpu_idle with preempt disabled */

  	cpu_idle();
  } 
  
  /* Check for early params. */
  static int __init do_early_param(char *param, char *val)
  {
  	struct obs_kernel_param *p;
  
  	for (p = __setup_start; p < __setup_end; p++) {
  		if (p->early && strcmp(param, p->str) == 0) {
  			if (p->setup_func(val) != 0)
  				printk(KERN_WARNING
  				       "Malformed early option '%s'
  ", param);
  		}
  	}
  	/* We accept everything at this stage. */
  	return 0;
  }
  
  /* Arch code calls this early on, or if not, just before other parsing. */
  void __init parse_early_param(void)
  {
  	static __initdata int done = 0;
  	static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
  
  	if (done)
  		return;
  
  	/* All fall through to do_early_param. */
  	strlcpy(tmp_cmdline, saved_command_line, COMMAND_LINE_SIZE);
  	parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
  	done = 1;
  }
  
  /*
   *	Activate the first processor.
   */

  static void __init boot_cpu_init(void)
  {
  	int cpu = smp_processor_id();
  	/* Mark the boot cpu "present", "online" etc for SMP and UP case */
  	cpu_set(cpu, cpu_online_map);
  	cpu_set(cpu, cpu_present_map);
  	cpu_set(cpu, cpu_possible_map);
  }

  void __init __attribute__((weak)) smp_setup_processor_id(void)
  {
  }

  asmlinkage void __init start_kernel(void)
  {
  	char * command_line;
  	extern struct kernel_param __start___param[], __stop___param[];

  
  	smp_setup_processor_id();

  	/*
  	 * Need to run as early as possible, to initialize the
  	 * lockdep hash:
  	 */
  	lockdep_init();
  
  	local_irq_disable();
  	early_boot_irqs_off();

  	early_init_irq_lock_class();

  /*
   * Interrupts are still disabled. Do necessary setups, then
   * enable them
   */
  	lock_kernel();

  	boot_cpu_init();

  	page_address_init();
  	printk(KERN_NOTICE);
  	printk(linux_banner);
  	setup_arch(&command_line);
  	setup_per_cpu_areas();

  	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */

  
  	/*
  	 * Set up the scheduler prior starting any interrupts (such as the
  	 * timer interrupt). Full topology setup happens at smp_init()
  	 * time - but meanwhile we still have a functioning scheduler.
  	 */
  	sched_init();
  	/*
  	 * Disable preemption - early bootup scheduling is extremely
  	 * fragile until we cpu_idle() for the first time.
  	 */
  	preempt_disable();
  	build_all_zonelists();
  	page_alloc_init();
  	printk(KERN_NOTICE "Kernel command line: %s
  ", saved_command_line);
  	parse_early_param();
  	parse_args("Booting kernel", command_line, __start___param,
  		   __stop___param - __start___param,
  		   &unknown_bootoption);
  	sort_main_extable();

  	unwind_init();

  	trap_init();
  	rcu_init();
  	init_IRQ();
  	pidhash_init();
  	init_timers();

  	hrtimers_init();

  	softirq_init();

  	timekeeping_init();

  	time_init();

  	profile_init();
  	if (!irqs_disabled())
  		printk("start_kernel(): bug: interrupts were enabled early
  ");

  	early_boot_irqs_on();

  	local_irq_enable();

  
  	/*
  	 * 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();
  	if (panic_later)
  		panic(panic_later, panic_param);

  
  	lockdep_info();

  	/*
  	 * Need to run this when irqs are enabled, because it wants
  	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
  	 * too:
  	 */
  	locking_selftest();

  #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.
  ",initrd_start,min_low_pfn << PAGE_SHIFT);
  		initrd_start = 0;
  	}
  #endif
  	vfs_caches_init_early();

  	cpuset_init_early();

  	mem_init();
  	kmem_cache_init();

  	setup_per_cpu_pageset();

  	numa_policy_init();
  	if (late_time_init)
  		late_time_init();
  	calibrate_delay();
  	pidmap_init();
  	pgtable_cache_init();
  	prio_tree_init();
  	anon_vma_init();
  #ifdef CONFIG_X86
  	if (efi_enabled)
  		efi_enter_virtual_mode();
  #endif
  	fork_init(num_physpages);
  	proc_caches_init();
  	buffer_init();
  	unnamed_dev_init();
  	key_init();
  	security_init();
  	vfs_caches_init(num_physpages);
  	radix_tree_init();
  	signals_init();
  	/* rootfs populating might need page-writeback */
  	page_writeback_init();
  #ifdef CONFIG_PROC_FS
  	proc_root_init();
  #endif
  	cpuset_init();

  	taskstats_init_early();

  	delayacct_init();

  
  	check_bugs();
  
  	acpi_early_init(); /* before LAPIC and SMP init */
  
  	/* Do the rest non-__init'ed, we're now alive */
  	rest_init();
  }
  
  static int __initdata initcall_debug;
  
  static int __init initcall_debug_setup(char *str)
  {
  	initcall_debug = 1;
  	return 1;
  }
  __setup("initcall_debug", initcall_debug_setup);
  
  struct task_struct *child_reaper = &init_task;
  
  extern initcall_t __initcall_start[], __initcall_end[];
  
  static void __init do_initcalls(void)
  {
  	initcall_t *call;
  	int count = preempt_count();
  
  	for (call = __initcall_start; call < __initcall_end; call++) {

  		char *msg = NULL;
  		char msgbuf[40];
  		int result;

  
  		if (initcall_debug) {

  			printk("Calling initcall 0x%p", *call);
  			print_fn_descriptor_symbol(": %s()",
  					(unsigned long) *call);

  			printk("
  ");
  		}

  		result = (*call)();

  		if (result && result != -ENODEV && initcall_debug) {

  			sprintf(msgbuf, "error code %d", result);
  			msg = msgbuf;
  		}

  		if (preempt_count() != count) {
  			msg = "preemption imbalance";
  			preempt_count() = count;
  		}
  		if (irqs_disabled()) {
  			msg = "disabled interrupts";
  			local_irq_enable();
  		}
  		if (msg) {

  			printk(KERN_WARNING "initcall at 0x%p", *call);
  			print_fn_descriptor_symbol(": %s()",
  					(unsigned long) *call);
  			printk(": returned with %s
  ", msg);

  		}
  	}
  
  	/* Make sure there is no pending stuff from the initcall sequence */
  	flush_scheduled_work();
  }
  
  /*
   * 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)
  {
  	/* drivers will send hotplug events */
  	init_workqueues();
  	usermodehelper_init();
  	driver_init();
  
  #ifdef CONFIG_SYSCTL
  	sysctl_init();
  #endif

  	do_initcalls();
  }
  
  static void do_pre_smp_initcalls(void)
  {
  	extern int spawn_ksoftirqd(void);
  #ifdef CONFIG_SMP
  	extern int migration_init(void);
  
  	migration_init();
  #endif
  	spawn_ksoftirqd();

  	spawn_softlockup_task();

  }
  
  static void run_init_process(char *init_filename)
  {
  	argv_init[0] = init_filename;
  	execve(init_filename, argv_init, envp_init);
  }

  static int init(void * unused)
  {
  	lock_kernel();
  	/*
  	 * init can run on any cpu.
  	 */
  	set_cpus_allowed(current, CPU_MASK_ALL);
  	/*
  	 * 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;

  	smp_prepare_cpus(max_cpus);
  
  	do_pre_smp_initcalls();

  	smp_init();
  	sched_init_smp();
  
  	cpuset_init_smp();
  
  	/*
  	 * Do this before initcalls, because some drivers want to access
  	 * firmware files.
  	 */
  	populate_rootfs();
  
  	do_basic_setup();
  
  	/*
  	 * check if there is an early userspace init.  If yes, let it do all
  	 * the work
  	 */

  
  	if (!ramdisk_execute_command)
  		ramdisk_execute_command = "/init";
  
  	if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
  		ramdisk_execute_command = NULL;

  		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();

  	mark_rodata_ro();

  	system_state = SYSTEM_RUNNING;
  	numa_default_policy();
  
  	if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
  		printk(KERN_WARNING "Warning: unable to open an initial console.
  ");
  
  	(void) sys_dup(0);
  	(void) sys_dup(0);

  
  	if (ramdisk_execute_command) {
  		run_init_process(ramdisk_execute_command);
  		printk(KERN_WARNING "Failed to execute %s
  ",
  				ramdisk_execute_command);
  	}

  	/*
  	 * 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);

  		printk(KERN_WARNING "Failed to execute %s.  Attempting "
  					"defaults...
  ", 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.");
  }