/* * 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/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/lockdep.h> #include <linux/pid_namespace.h> #include <linux/device.h> #include <linux/kthread.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 #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 signals_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_ACPI extern void acpi_early_init(void); #else static inline void acpi_early_init(void) { } #endif #ifndef CONFIG_DEBUG_RODATA static inline void mark_rodata_ro(void) { } #endif #ifdef CONFIG_TC extern 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; /* Setup configured maximum number of CPUs to activate */ static unsigned int max_cpus = NR_CPUS; /* * 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); /* * 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 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) { 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_APIC static 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_CPU unsigned 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 /* !__GENERIC_PER_CPU */ /* 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() >= 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(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(pid); 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) { 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, boot_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); } void __init __attribute__((weak)) smp_setup_processor_id(void) { } 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: */ unwind_init(); lockdep_init(); 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); printk(linux_banner); setup_arch(&command_line); setup_command_line(command_line); unwind_setup(); 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", boot_command_line); parse_early_param(); parse_args("Booting kernel", static_command_line, __start___param, __stop___param - __start___param, &unknown_bootoption); if (!irqs_disabled()) { printk(KERN_WARNING "start_kernel(): bug: interrupts were " "enabled *very* early, fixing it\n"); local_irq_disable(); } sort_main_extable(); trap_init(); rcu_init(); init_IRQ(); pidhash_init(); init_timers(); hrtimers_init(); softirq_init(); timekeeping_init(); time_init(); profile_init(); if (!irqs_disabled()) printk("start_kernel(): bug: interrupts were enabled early\n"); early_boot_irqs_on(); local_irq_enable(); /* * 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 && initrd_start < min_low_pfn << PAGE_SHIFT) { printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - " "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT); initrd_start = 0; } #endif vfs_caches_init_early(); cpuset_init_early(); mem_init(); kmem_cache_init(); setup_per_cpu_pageset(); numa_policy_init(); if (late_time_init) late_time_init(); calibrate_delay(); pidmap_init(); pgtable_cache_init(); prio_tree_init(); anon_vma_init(); #ifdef CONFIG_X86 if (efi_enabled) efi_enter_virtual_mode(); #endif fork_init(num_physpages); proc_caches_init(); buffer_init(); unnamed_dev_init(); key_init(); security_init(); vfs_caches_init(num_physpages); radix_tree_init(); signals_init(); /* rootfs populating might need page-writeback */ page_writeback_init(); #ifdef CONFIG_PROC_FS proc_root_init(); #endif cpuset_init(); taskstats_init_early(); delayacct_init(); check_bugs(); acpi_early_init(); /* before LAPIC and SMP init */ /* Do the rest non-__init'ed, we're now alive */ rest_init(); } static int __initdata initcall_debug; static int __init initcall_debug_setup(char *str) { initcall_debug = 1; return 1; } __setup("initcall_debug", initcall_debug_setup); extern initcall_t __initcall_start[], __initcall_end[]; static void __init do_initcalls(void) { initcall_t *call; int count = preempt_count(); for (call = __initcall_start; call < __initcall_end; call++) { ktime_t t0, t1, delta; char *msg = NULL; char msgbuf[40]; int result; if (initcall_debug) { printk("Calling initcall 0x%p", *call); print_fn_descriptor_symbol(": %s()", (unsigned long) *call); printk("\n"); t0 = ktime_get(); } result = (*call)(); if (initcall_debug) { t1 = ktime_get(); delta = ktime_sub(t1, t0); printk("initcall 0x%p", *call); print_fn_descriptor_symbol(": %s()", (unsigned long) *call); printk(" returned %d.\n", result); printk("initcall 0x%p ran for %Ld msecs: ", *call, (unsigned long long)delta.tv64 >> 20); print_fn_descriptor_symbol("%s()\n", (unsigned long) *call); } if (result && result != -ENODEV && initcall_debug) { sprintf(msgbuf, "error code %d", result); msg = msgbuf; } if (preempt_count() != count) { msg = "preemption imbalance"; preempt_count() = count; } if (irqs_disabled()) { msg = "disabled interrupts"; local_irq_enable(); } if (msg) { printk(KERN_WARNING "initcall at 0x%p", *call); print_fn_descriptor_symbol(": %s()", (unsigned long) *call); printk(": returned with %s\n", msg); } } /* 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) { /* drivers will send hotplug events */ init_workqueues(); usermodehelper_init(); driver_init(); init_irq_proc(); do_initcalls(); } static void __init do_pre_smp_initcalls(void) { extern int spawn_ksoftirqd(void); #ifdef CONFIG_SMP extern int migration_init(void); migration_init(); #endif spawn_ksoftirqd(); spawn_softlockup_task(); } 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 int noinline init_post(void) { 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); 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 run on any cpu. */ set_cpus_allowed(current, CPU_MASK_ALL); /* * 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; __set_special_pids(1, 1); cad_pid = task_pid(current); smp_prepare_cpus(max_cpus); do_pre_smp_initcalls(); smp_init(); sched_init_smp(); cpuset_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; }