/* *  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>  */ #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/start_kernel.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/cgroup.h>#include <linux/efi.h>#include <linux/tick.h>#include <linux/interrupt.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/debugobjects.h>#include <linux/lockdep.h>#include <linux/pid_namespace.h>#include <linux/device.h>#include <linux/kthread.h>#include <linux/sched.h>#include <linux/signal.h>#include <linux/idr.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. */ #if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0#warning gcc-4.1.0 is known to miscompile the kernel.  A different compiler version is recommended.#endif static int kernel_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 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);#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 saved by arch-specific code. */char __initdata boot_command_line[COMMAND_LINE_SIZE];/* Untouched saved command line (eg. for /proc) */char *saved_command_line;/* Command line for parameter parsing */static char *static_command_line; static char *execute_command;static char *ramdisk_execute_command; #ifdef CONFIG_SMP/* Setup configured maximum number of CPUs to activate */unsigned int __initdata setup_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>. */#ifndef CONFIG_X86_IO_APICstatic inline void disable_ioapic_setup(void) {};#endif static int __init nosmp(char *str){	setup_max_cpus = 0;	disable_ioapic_setup();	return 0;} early_param("nosmp", nosmp); static int __init maxcpus(char *str){	get_option(&str, &setup_max_cpus);	if (setup_max_cpus == 0)		disable_ioapic_setup(); 	return 0;} early_param("maxcpus", maxcpus);#else#define setup_max_cpus NR_CPUS#endif /* * If set, this is an indication to the drivers that reset the underlying * device before going ahead with the initialization otherwise driver might * rely on the BIOS and skip the reset operation. * * This is useful if kernel is booting in an unreliable environment. * For ex. kdump situaiton where previous kernel has crashed, BIOS has been * skipped and devices will be in unknown state. */unsigned int reset_devices;EXPORT_SYMBOL(reset_devices); static int __init set_reset_devices(char *str){	reset_devices = 1;	return 1;} __setup("reset_devices", set_reset_devices); 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;	int had_early_param = 0; 	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).				 * Keep iterating, as we can have early				 * params and __setups of same names 8( */				if (line[n] == '\0' || line[n] == '=')					had_early_param = 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 had_early_param;} /* * 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){	console_loglevel = 10;	return 0;} static int __init quiet_kernel(char *str){	console_loglevel = 4;	return 0;} early_param("debug", debug_kernel);early_param("quiet", quiet_kernel); static int __init loglevel(char *str){	get_option(&str, &console_loglevel);	return 0;} early_param("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 misspelled 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;} #ifdef CONFIG_DEBUG_PAGEALLOCint __read_mostly debug_pagealloc_enabled = 0;#endif 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 setup_nr_cpu_ids(void) { }static inline void smp_prepare_cpus(unsigned int maxcpus) { } #else #if NR_CPUS > BITS_PER_LONGcpumask_t cpu_mask_all __read_mostly = CPU_MASK_ALL;EXPORT_SYMBOL(cpu_mask_all);#endif /* Setup number of possible processor ids */int nr_cpu_ids __read_mostly = NR_CPUS;EXPORT_SYMBOL(nr_cpu_ids); /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */static void __init setup_nr_cpu_ids(void){	int cpu, highest_cpu = 0; 	for_each_possible_cpu(cpu)		highest_cpu = cpu; 	nr_cpu_ids = highest_cpu + 1;} #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREAunsigned 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(PERCPU_ENOUGH_ROOM, PAGE_SIZE);	ptr = alloc_bootmem_pages(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 /* CONFIG_HAVE_SETUP_PER_CPU_AREA */ /* Called by boot processor to activate the rest. */static void __init smp_init(void){	unsigned int cpu; 	/* FIXME: This should be done in userspace --RR */	for_each_present_cpu(cpu) {		if (num_online_cpus() >= setup_max_cpus)			break;		if (!cpu_online(cpu))			cpu_up(cpu);	} 	/* Any cleanup work */	printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());	smp_cpus_done(setup_max_cpus);} #endif /* * We need to store the untouched command line for future reference. * We also need to store the touched command line since the parameter * parsing is performed in place, and we should allow a component to * store reference of name/value for future reference. */static void __init setup_command_line(char *command_line){	saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);	static_command_line = alloc_bootmem(strlen (command_line)+1);	strcpy (saved_command_line, boot_command_line);	strcpy (static_command_line, command_line);} /* * 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 __init_refok rest_init(void)	__releases(kernel_lock){	int pid; 	kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);	numa_default_policy();	pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);	kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);	unlock_kernel(); 	/*	 * The boot idle thread must execute schedule()	 * at least once to get things moving:	 */	init_idle_bootup_task(current);	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) ||		    (strcmp(param, "console") == 0 &&		     strcmp(p->str, "earlycon") == 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){

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