/* *  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 <linux/profile.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_IRDAextern 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.#endifextern 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 pte_chain_init(void);extern void free_initmem(void);extern void pidhash_init(void);#ifdef CONFIG_TCextern void tc_init(void);#endifextern 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 8extern 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, };__setup("profile=", profile_setup);int disable_all_usb = 0;static int __init no_usb(char * s){	disable_all_usb = 1;	return 1;}__setup("nousb", no_usb);extern int max_recursive_link;static int __init overflowmeharder(char * s){	if (strstr(s,"overflowmeharder"))		max_recursive_link = 8;	return 0;}__setup("stack",overflowmeharder);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 8void __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);#ifndef CONFIG_SMP#ifdef CONFIG_X86_LOCAL_APICstatic 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();	smp_threads_ready=1;	smp_commence();}#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){	init_idle(current, smp_processor_id());	kernel_thread(init, NULL, CLONE_KERNEL);	unlock_kernel();	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	profile_init();	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();	pidhash_init();	pgtable_cache_init();	pte_chain_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");	/* Do the rest non-__init'ed, we're now alive */	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();	smp_init();#if CONFIG_SMP	migration_init();#endif	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.");}