/* * linux/init/main.c * * Copyright (C) 1991, 1992 Linus Torvalds *草稿箱 * 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/smp_lock.h>#include <linux/initrd.h>#include <linux/bootmem.h>#include <linux/acpi.h>#include <linux/tty.h>#include <linux/gfp.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/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/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/ftrace.h>#include <linux/async.h>#include <linux/kmemcheck.h>#include <linux/kmemtrace.h>#include <linux/sfi.h>#include <linux/shmem_fs.h>#include <trace/boot.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>#endifstatic 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);#endifenum 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_LIMITextern 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;#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>. */void __weak arch_disable_smp_support(void) { }static int __init nosmp(char *str){setup_max_cpus = 0;arch_disable_smp_support();return 0;}early_param("nosmp", nosmp);static int __init maxcpus(char *str){get_option(&str, &setup_max_cpus);if (setup_max_cpus == 0)arch_disable_smp_support();return 0;}early_param("maxcpus", maxcpus);#elseconst unsigned int 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 * 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--;} elseBUG();}/* 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;}#ifdef CONFIG_DEBUG_PAGEALLOCint __read_mostly debug_pagealloc_enabled = 0;#endifstatic 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)#endifstatic inline void setup_nr_cpu_ids(void) { }static inline void smp_prepare_cpus(unsigned int maxcpus) { }#else/* 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){nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;}/* Called by boot processor to activate the rest. */static void __init smp_init(void){unsigned int cpu;/* * Set up the current CPU as possible to migrate to. * The other ones will be done by cpu_up/cpu_down() */set_cpu_active(smp_processor_id(), true);/* 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 noinline void __init_refok rest_init(void)__releases(kernel_lock){int pid;rcu_scheduler_starting();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;}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_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();pgtable_cache_init();vmalloc_init();}asmlinkage void __init start_kernel(void){char * command_line;extern struct kernel_param __start___param[], __stop___param[];smp_setup_processor_id();/* * Need to run as early as possible, to initialize the * lockdep hash: */lockdep_init();debug_objects_early_init();/* * Set up the the initial canary ASAP: */boot_init_stack_canary();cgroup_init_early();local_irq_disable();early_boot_irqs_off();early_init_irq_lock_class();/* * Interrupts are still disabled. Do necessary setups, then * enable them */lock_kernel();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);setup_command_line(command_line);setup_nr_cpu_ids();setup_per_cpu_areas();smp_prepare_boot_cpu();/* arch-specific boot-cpu hooks */build_all_zonelists();page_alloc_init();printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);parse_early_param();parse_args("Booting kernel", static_command_line, __start___param, __stop___param - __start___param, &unknown_bootoption);/* * These use large bootmem allocations and must precede * kmem_cache_init() */pidhash_init();vfs_caches_init_early();sort_main_extable();trap_init();mm_init();/* * 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();if (!irqs_disabled()) {printk(KERN_WARNING "start_kernel(): bug: interrupts were ""enabled *very* early, fixing it\n");local_irq_disable();}rcu_init();/* init some links before init_ISA_irqs() */early_irq_init();init_IRQ();prio_tree_init();init_timers();hrtimers_init();softirq_init();timekeeping_init();time_init();profile_init();if (!irqs_disabled())printk(KERN_CRIT "start_kernel(): bug: interrupts were " "enabled early\n");early_boot_irqs_on();local_irq_enable();/* Interrupts are enabled now so all GFP allocations are safe. */set_gfp_allowed_mask(__GFP_BITS_MASK);kmem_cache_init_late();/* * 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)panic(panic_later, panic_param);lockdep_info();/* * Need to run this when irqs are enabled, because it wants * to self-test [hard/soft]-irqs on/off lock inversion bugs * too: */locking_selftest();#ifdef CONFIG_BLK_DEV_INITRDif (initrd_start && !initrd_below_start_ok && page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " "disabling it.\n", page_to_pfn(virt_to_page((void *)initrd_start)), min_low_pfn);initrd_start = 0;}#endifpage_cgroup_init();enable_debug_pagealloc();kmemtrace_init();kmemleak_init();debug_objects_mem_init();idr_init_cache();setup_per_cpu_pageset();numa_policy_init();if (late_time_init)late_time_init();sched_clock_init();calibrate_delay();pidmap_init();anon_vma_init();#ifdef CONFIG_X86if (efi_enabled)efi_enter_virtual_mode();#endifthread_info_cache_init();cred_init();fork_init(totalram_pages);proc_caches_init();buffer_init();key_init();security_init();vfs_caches_init(totalram_pages);radix_tree_init();signals_init();/* rootfs populating might need page-writeback */page_writeback_init();#ifdef CONFIG_PROC_FSproc_root_init();#endifcgroup_init();cpuset_init();taskstats_init_early();delayacct_init();check_bugs();acpi_early_init(); /* before LAPIC and SMP init */sfi_init_late();ftrace_init();/* Do the rest non-__init'ed, we're now alive */rest_init();}/* Call all constructor functions linked into the kernel. */static void __init do_ctors(void){#ifdef CONFIG_CONSTRUCTORSctor_fn_t *fn = (ctor_fn_t *) __ctors_start;for (; fn < (ctor_fn_t *) __ctors_end; fn++)(*fn)();#endif}int initcall_debug;core_param(initcall_debug, initcall_debug, bool, 0644);static char msgbuf[64];static struct boot_trace_call call;static struct boot_trace_ret ret;int do_one_initcall(initcall_t fn){int count = preempt_count();ktime_t calltime, delta, rettime;if (initcall_debug) {call.caller = task_pid_nr(current);printk("calling %pF @ %i\n", fn, call.caller);calltime = ktime_get();trace_boot_call(&call, fn);enable_boot_trace();}ret.result = fn();if (initcall_debug) {disable_boot_trace();rettime = ktime_get();delta = ktime_sub(rettime, calltime);ret.duration = (unsigned long long) ktime_to_ns(delta) >> 10;trace_boot_ret(&ret, fn);printk("initcall %pF returned %d after %Ld usecs\n", fn,ret.result, ret.duration);}msgbuf[0] = 0;if (ret.result && ret.result != -ENODEV && initcall_debug)sprintf(msgbuf, "error code %d ", ret.result);if (preempt_count() != count) {strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));preempt_count() = count;}if (irqs_disabled()) {strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));local_irq_enable();}if (msgbuf[0]) {printk("initcall %pF returned with %s\n", fn, msgbuf);}return ret.result;}extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];static void __init do_initcalls(void){initcall_t *fn;for (fn = __early_initcall_end; fn < __initcall_end; fn++)do_one_initcall(*fn);/* Make sure there is no pending stuff from the initcall sequence */flush_scheduled_work();}/* * 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){init_workqueues();cpuset_init_smp();usermodehelper_init();init_tmpfs();driver_init();init_irq_proc();do_ctors();do_initcalls();}static void __init do_pre_smp_initcalls(void){initcall_t *fn;for (fn = __initcall_start; fn < __early_initcall_end; fn++)do_one_initcall(*fn);}static void run_init_process(char *init_filename){argv_init[0] = init_filename;kernel_execve(init_filename, argv_init, envp_init);}/* This is a non __init function. Force it to be noinline otherwise gcc * makes it inline to init() and it becomes part of init.text section */static noinline int init_post(void)__releases(kernel_lock){/* need to finish all async __init code before freeing the memory */async_synchronize_full();free_initmem();unlock_kernel();mark_rodata_ro();system_state = SYSTEM_RUNNING;numa_default_policy();if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)printk(KERN_WARNING "Warning: unable to open an initial console.\n");(void) sys_dup(0);(void) sys_dup(0);current->signal->flags |= SIGNAL_UNKILLABLE;if (ramdisk_execute_command) {run_init_process(ramdisk_execute_command);printk(KERN_WARNING "Failed to execute %s\n",ramdisk_execute_command);}/* * 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) {run_init_process(execute_command);printk(KERN_WARNING "Failed to execute %s. Attempting ""defaults...\n", execute_command);}run_init_process("/sbin/init");run_init_process("/etc/init");run_init_process("/bin/init");run_init_process("/bin/sh");panic("No init found. Try passing init= option to kernel.");}static int __init kernel_init(void * unused){lock_kernel();/* * init can allocate pages on any node */set_mems_allowed(node_possible_map);/* * init can run on any cpu. */set_cpus_allowed_ptr(current, cpu_all_mask);/* * 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. */init_pid_ns.child_reaper = current;cad_pid = task_pid(current);smp_prepare_cpus(setup_max_cpus);do_pre_smp_initcalls();start_boot_trace();smp_init();sched_init_smp();do_basic_setup();/* * check if there is an early userspace init. If yes, let it do all * the work */if (!ramdisk_execute_command)ramdisk_execute_command = "/init";if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {ramdisk_execute_command = NULL;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.. */init_post();return 0;}
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