/* * 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_RODATA static inline void mark_rodata_ro(void) { } #endif #ifdef CONFIG_TC extern 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; #ifdef CONFIG_SMP /* Setup configured maximum number of CPUs to activate */ unsigned int setup_max_cpus = NR_CPUS; EXPORT_SYMBOL(setup_max_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); /* this is hard limit */ static int __init nrcpus(char *str) { int nr_cpus; get_option(&str, &nr_cpus); if (nr_cpus > 0 && nr_cpus < nr_cpu_ids) nr_cpu_ids = nr_cpus; return 0; } early_param("nr_cpus", nrcpus); 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); #else static const 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 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 (!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--; } 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; } #ifdef CONFIG_DEBUG_PAGEALLOC int __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_APIC static 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) { } #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; /* 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 __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(); 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) { const 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_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[]; 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_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); 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(NULL); 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(); } idr_init_cache(); perf_event_init(); rcu_init(); radix_tree_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_disabled = false; local_irq_enable(); /* Interrupts are enabled now so all GFP allocations are safe. */ 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_INITRD if (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; } #endif page_cgroup_init(); enable_debug_pagealloc(); kmemleak_init(); debug_objects_mem_init(); 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_X86 if (efi_enabled) efi_enter_virtual_mode(); #endif thread_info_cache_init(); cred_init(); fork_init(totalram_pages); proc_caches_init(); buffer_init(); key_init(); security_init(); dbg_late_init(); vfs_caches_init(totalram_pages); signals_init(); /* rootfs populating might need page-writeback */ page_writeback_init(); #ifdef CONFIG_PROC_FS proc_root_init(); #endif cgroup_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_CONSTRUCTORS ctor_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 int __init_or_module do_one_initcall_debug(initcall_t fn) { ktime_t calltime, delta, rettime; unsigned long long duration; int ret; printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current)); calltime = ktime_get(); ret = fn(); rettime = ktime_get(); delta = ktime_sub(rettime, calltime); duration = (unsigned long long) ktime_to_ns(delta) >> 10; printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n", fn, ret, duration); return ret; } int __init_or_module do_one_initcall(initcall_t fn) { int count = preempt_count(); int ret; if (initcall_debug) ret = do_one_initcall_debug(fn); else ret = fn(); msgbuf[0] = 0; if (ret && ret != -ENODEV && initcall_debug) sprintf(msgbuf, "error code %d ", ret); 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; } 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); } /* * 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) { 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(const 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) { /* need to finish all async __init code before freeing the memory */ async_synchronize_full(); free_initmem(); mark_rodata_ro(); system_state = SYSTEM_RUNNING; numa_default_policy(); 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. " "See Linux Documentation/init.txt for guidance."); } static int __init kernel_init(void * unused) { /* * Wait until kthreadd is all set-up. */ wait_for_completion(&kthreadd_done); /* * init can allocate pages on any node */ set_mems_allowed(node_states[N_HIGH_MEMORY]); /* * 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(); lockup_detector_init(); smp_init(); sched_init_smp(); do_basic_setup(); /* Open the /dev/console on the rootfs, this should never fail */ 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); /* * 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; }