/* *  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/cpuset.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>#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 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_ACPIextern void acpi_early_init(void);#elsestatic inline void acpi_early_init(void) { }#endif#ifndef CONFIG_DEBUG_RODATAstatic inline void mark_rodata_ro(void) { }#endif #ifdef CONFIG_TCextern 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\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); 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\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); 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_APICstatic 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_CPUunsigned 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\n", (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'\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. */ 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);} 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();	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\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();	hrtimers_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();	if (panic_later)

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