/* *  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/stackprotector.h>#include <linux/string.h>#include <linux/ctype.h>#include <linux/delay.h>#include <linux/ioport.h>#include <linux/init.h>#include <linux/initrd.h>#include <linux/bootmem.h>#include <linux/acpi.h>#include <linux/tty.h>#include <linux/percpu.h>#include <linux/kmod.h>#include <linux/vmalloc.h>#include <linux/kernel_stat.h>#include <linux/start_kernel.h>#include <linux/security.h>#include <linux/smp.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/buffer_head.h>#include <linux/page_cgroup.h>#include <linux/debug_locks.h>#include <linux/debugobjects.h>#include <linux/lockdep.h>#include <linux/kmemleak.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 <linux/kgdb.h>#include <linux/ftrace.h>#include <linux/async.h>#include <linux/kmemcheck.h>#include <linux/sfi.h>#include <linux/shmem_fs.h>#include <linux/slab.h>#include <linux/perf_event.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 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 prio_tree_init(void);extern void radix_tree_init(void);extern void free_initmem(void);#ifndef CONFIG_DEBUG_RODATAstatic inline void mark_rodata_ro(void) { }#endif #ifdef CONFIG_TCextern void tc_init(void);#endif /* * Debug helper: via this flag we know that we are in 'early bootup code' * where only the boot processor is running with IRQ disabled.  This means * two things - IRQ must not be enabled before the flag is cleared and some * operations which are not allowed with IRQ disabled are allowed while the * flag is set. */bool early_boot_irqs_disabled __read_mostly; enum system_states system_state __read_mostly;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 (*__initdata 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; /* * 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 const char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };const char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };static const char *panic_later, *panic_param; extern const struct obs_kernel_param __setup_start[], __setup_end[]; static int __init obsolete_checksetup(char *line){	const struct obs_kernel_param *p;	int had_early_param = 0; 	p = __setup_start;	do {		int n = strlen(p->str);		if (parameqn(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){	int newlevel; 	/*	 * Only update loglevel value when a correct setting was passed,	 * to prevent blind crashes (when loglevel being set to 0) that	 * are quite hard to debug	 */	if (get_option(&str, &newlevel)) {		console_loglevel = newlevel;		return 0;	} 	return -EINVAL;} early_param("loglevel", loglevel); /* * Unknown boot options get handed to init, unless they look like * unused parameters (modprobe will find them in /proc/cmdline). */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; 	/* Unused module parameter. */	if (strchr(param, '.') && (!val || strchr(param, '.') < val))		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_SMPstatic const unsigned int setup_max_cpus = NR_CPUS;#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_nr_cpu_ids(void) { }static inline void smp_prepare_cpus(unsigned int maxcpus) { }#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 __initdata DECLARE_COMPLETION(kthreadd_done); static noinline void __init_refok rest_init(void){	int pid; 	rcu_scheduler_starting();	/*	 * We need to spawn init first so that it obtains pid 1, however	 * the init task will end up wanting to create kthreads, which, if	 * we schedule it before we create kthreadd, will OOPS.	 */	kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);	numa_default_policy();	pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);	rcu_read_lock();	kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);	rcu_read_unlock();	complete(&kthreadd_done); 	/*	 * The boot idle thread must execute schedule()	 * at least once to get things moving:	 */	init_idle_bootup_task(current);	preempt_enable_no_resched();	schedule(); 	/* Call into cpu_idle with preempt disabled */	preempt_disable();	cpu_idle();} /* Check for early params. */static int __init do_early_param(char *param, char *val){	const struct obs_kernel_param *p; 	for (p = __setup_start; p < __setup_end; p++) {		if ((p->early && parameq(param, p->str)) ||		    (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;} void __init parse_early_options(char *cmdline){	parse_args("early options", cmdline, NULL, 0, do_early_param);} /* 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, boot_command_line, COMMAND_LINE_SIZE);	parse_early_options(tmp_cmdline);	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 */	set_cpu_online(cpu, true);	set_cpu_active(cpu, true);	set_cpu_present(cpu, true);	set_cpu_possible(cpu, true);} void __init __weak smp_setup_processor_id(void){} void __init __weak thread_info_cache_init(void){} /* * Set up kernel memory allocators */static void __init mm_init(void){	/*	 * page_cgroup requires countinous pages as memmap	 * and it's bigger than MAX_ORDER unless SPARSEMEM.	 */	page_cgroup_init_flatmem();	mem_init();	kmem_cache_init();	percpu_init_late();	pgtable_cache_init();	vmalloc_init();} asmlinkage void __init start_kernel(void){	char * command_line;	extern const struct kernel_param __start___param[], __stop___param[]; 	/*	 * Need to run as early as possible, to initialize the	 * lockdep hash:	 */	lockdep_init();	smp_setup_processor_id();	debug_objects_early_init(); 	/*	 * Set up the the initial canary ASAP:	 */	boot_init_stack_canary(); 	cgroup_init_early(); 	local_irq_disable();	early_boot_irqs_disabled = true; /* * Interrupts are still disabled. Do necessary setups, then * enable them */	tick_init();	boot_cpu_init();	page_address_init();	printk(KERN_NOTICE "%s", linux_banner);	setup_arch(&command_line);	mm_init_owner(&init_mm, &init_task);	mm_init_cpumask(&init_mm);	setup_command_line(command_line);	setup_nr_cpu_ids();	setup_per_cpu_areas();	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */

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