C

 /*
  *  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/types.h>

 #include <linux/module.h>
 #include <linux/proc_fs.h>
 #include <linux/devfs_fs_kernel.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/efi.h>
 #include <linux/unistd.h>
 #include <linux/rmap.h>
 #include <linux/mempolicy.h>

 #include <linux/key.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>

 #include <asm/setup.h>
 
 /*
  * This is one of the first .c files built. Error out early
  * if we have compiler trouble..

  */
 #if __GNUC__ == 2 && __GNUC_MINOR__ == 96
 #ifdef CONFIG_FRAME_POINTER
 #error This compiler cannot compile correctly with frame pointers enabled

 #endif
 #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__ < 95)

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

 extern void sock_init(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 buffer_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
 

 #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 32
 #define MAX_INIT_ENVS 32

 
 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;

 
 /* 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\n", 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);

 
 /*
  * 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\n", 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);

 
 extern void setup_arch(char **);
 
 #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];
 
 EXPORT_SYMBOL(__per_cpu_offset);
 

 static void __init setup_per_cpu_areas(void)
 {
         unsigned long size, i;

         char *ptr;
         /* Created by linker magic */
         extern char __per_cpu_start[], __per_cpu_end[];
 

         /* 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_CPUS);

 
         for (i = 0; i < NR_CPUS; i++, ptr += size) {

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

         }
 }
 #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("Brought up %ld CPUs\n", (long)num_online_cpus());
         smp_cpus_done(max_cpus);

 #if 0
         /* Get other processors into their bootup holding patterns. */
 
         smp_threads_ready=1;
         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();
         preempt_enable_no_resched();
         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'\n", 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.
  */
 

 asmlinkage void __init start_kernel(void)
 {
         char * command_line;

         extern struct kernel_param __start___param[], __stop___param[];
 /*
  * Interrupts are still disabled. Do necessary setups, then

  * enable them
  */
         lock_kernel();
         page_address_init();

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

         /*
          * Mark the boot cpu "online" so that it can call console drivers in
          * printk() and can access its per-cpu storage.
          */

         smp_prepare_boot_cpu();
 
         /*
          * 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("Kernel command line: %s\n", saved_command_line);
         parse_early_param();

         parse_args("Booting kernel", command_line, __start___param,
                    __stop___param - __start___param,

                    &unknown_bootoption);
         sort_main_extable();
         trap_init();
         rcu_init();
         init_IRQ();

         pidhash_init();
         init_timers();
         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();
         if (panic_later)
                 panic(panic_later, panic_param);

         profile_init();
         local_irq_enable();
 #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
         vfs_caches_init_early();
         mem_init();
         kmem_cache_init();
         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();
         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
         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;
 
                 if (initcall_debug) {

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

                 }
 
                 (*call)();
 
                 msg = NULL;

                 if (preempt_count() != count) {
                         msg = "preemption imbalance";
                         preempt_count() = count;

                 }
                 if (irqs_disabled()) {
                         msg = "disabled interrupts";
                         local_irq_enable();

                 }
                 if (msg) {
                         printk("error in initcall at 0x%p: "
                                 "returned with %s\n", *call, 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();
         key_init();

         driver_init();
 
 #ifdef CONFIG_SYSCTL
         sysctl_init();
 #endif

 
         /* Networking initialization needs a process context */ 
         sock_init();
 
         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();

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

         execve(init_filename, argv_init, envp_init);
 }
 
 static inline void fixup_cpu_present_map(void)

 {
 #ifdef CONFIG_SMP
         int i;
 
         /*

          * If arch is not hotplug ready and did not populate
          * cpu_present_map, just make cpu_present_map same as cpu_possible_map
          * for other cpu bringup code to function as normal. e.g smp_init() etc.
          */

         if (cpus_empty(cpu_present_map)) {
                 for_each_cpu(i) {
                         cpu_set(i, cpu_present_map);

                 }
         }
 #endif
 }
 
 static int init(void * unused)

 {
         lock_kernel();
         /*
          * 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;
 
         /* Sets up cpus_possible() */

         smp_prepare_cpus(max_cpus);
 
         do_pre_smp_initcalls();
 
         fixup_cpu_present_map();

         smp_init();
         sched_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 (sys_access((const char __user *) "/init", 0) == 0)
                 execute_command = "/init";

         else
                 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();
         system_state = SYSTEM_RUNNING;
         numa_default_policy();
 
         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)

                 printk("Warning: unable to open an initial console.\n");
 
         (void) sys_dup(0);
         (void) sys_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.");

 }