/*
 *  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/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_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_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 **);
extern void cpu_idle(void);

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
#if defined(CONFIG_SYSVIPC)
        ipc_init();
#endif
        check_bugs();
        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();
        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_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
}

extern void prepare_namespace(void);

static int init(void * unused)
{
        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();

        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)
                execve(execute_command,argv_init,envp_init);
        execve("/sbin/init",argv_init,envp_init);
        execve("/etc/init",argv_init,envp_init);
        execve("/bin/init",argv_init,envp_init);
        execve("/bin/sh",argv_init,envp_init);
        panic("No init found.  Try passing init= option to kernel.");
}