4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * GK 2/5/95 - Changed to support mounting root fs via NFS
7 * Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
8 * Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
9 * Simplified starting of init: Michael A. Griffith <grif@acm.org>
12 #define DEBUG /* Enable initcall_debug */
14 #include <linux/types.h>
15 #include <linux/module.h>
16 #include <linux/proc_fs.h>
17 #include <linux/kernel.h>
18 #include <linux/syscalls.h>
19 #include <linux/stackprotector.h>
20 #include <linux/string.h>
21 #include <linux/ctype.h>
22 #include <linux/delay.h>
23 #include <linux/ioport.h>
24 #include <linux/init.h>
25 #include <linux/initrd.h>
26 #include <linux/bootmem.h>
27 #include <linux/acpi.h>
28 #include <linux/tty.h>
29 #include <linux/percpu.h>
30 #include <linux/kmod.h>
31 #include <linux/vmalloc.h>
32 #include <linux/kernel_stat.h>
33 #include <linux/start_kernel.h>
34 #include <linux/security.h>
35 #include <linux/smp.h>
36 #include <linux/profile.h>
37 #include <linux/rcupdate.h>
38 #include <linux/moduleparam.h>
39 #include <linux/kallsyms.h>
40 #include <linux/writeback.h>
41 #include <linux/cpu.h>
42 #include <linux/cpuset.h>
43 #include <linux/cgroup.h>
44 #include <linux/efi.h>
45 #include <linux/tick.h>
46 #include <linux/interrupt.h>
47 #include <linux/taskstats_kern.h>
48 #include <linux/delayacct.h>
49 #include <linux/unistd.h>
50 #include <linux/rmap.h>
51 #include <linux/mempolicy.h>
52 #include <linux/key.h>
53 #include <linux/buffer_head.h>
54 #include <linux/page_ext.h>
55 #include <linux/debug_locks.h>
56 #include <linux/debugobjects.h>
57 #include <linux/lockdep.h>
58 #include <linux/kmemleak.h>
59 #include <linux/pid_namespace.h>
60 #include <linux/device.h>
61 #include <linux/kthread.h>
62 #include <linux/sched.h>
63 #include <linux/signal.h>
64 #include <linux/idr.h>
65 #include <linux/kgdb.h>
66 #include <linux/ftrace.h>
67 #include <linux/async.h>
68 #include <linux/kmemcheck.h>
69 #include <linux/sfi.h>
70 #include <linux/shmem_fs.h>
71 #include <linux/slab.h>
72 #include <linux/perf_event.h>
73 #include <linux/file.h>
74 #include <linux/ptrace.h>
75 #include <linux/blkdev.h>
76 #include <linux/elevator.h>
77 #include <linux/sched_clock.h>
78 #include <linux/context_tracking.h>
79 #include <linux/random.h>
80 #include <linux/list.h>
81 #include <linux/integrity.h>
85 #include <asm/setup.h>
86 #include <asm/sections.h>
87 #include <asm/cacheflush.h>
89 #ifdef CONFIG_X86_LOCAL_APIC
93 static int kernel_init(void *);
95 extern void init_IRQ(void);
96 extern void fork_init(unsigned long);
97 extern void radix_tree_init(void);
98 #ifndef CONFIG_DEBUG_RODATA
99 static inline void mark_rodata_ro(void) { }
103 * Debug helper: via this flag we know that we are in 'early bootup code'
104 * where only the boot processor is running with IRQ disabled. This means
105 * two things - IRQ must not be enabled before the flag is cleared and some
106 * operations which are not allowed with IRQ disabled are allowed while the
109 bool early_boot_irqs_disabled __read_mostly;
111 enum system_states system_state __read_mostly;
112 EXPORT_SYMBOL(system_state);
115 * Boot command-line arguments
117 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
118 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
120 extern void time_init(void);
121 /* Default late time init is NULL. archs can override this later. */
122 void (*__initdata late_time_init)(void);
124 /* Untouched command line saved by arch-specific code. */
125 char __initdata boot_command_line[COMMAND_LINE_SIZE];
126 /* Untouched saved command line (eg. for /proc) */
127 char *saved_command_line;
128 /* Command line for parameter parsing */
129 static char *static_command_line;
130 /* Command line for per-initcall parameter parsing */
131 static char *initcall_command_line;
133 static char *execute_command;
134 static char *ramdisk_execute_command;
137 * Used to generate warnings if static_key manipulation functions are used
138 * before jump_label_init is called.
140 bool static_key_initialized __read_mostly;
141 EXPORT_SYMBOL_GPL(static_key_initialized);
144 * If set, this is an indication to the drivers that reset the underlying
145 * device before going ahead with the initialization otherwise driver might
146 * rely on the BIOS and skip the reset operation.
148 * This is useful if kernel is booting in an unreliable environment.
149 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
150 * skipped and devices will be in unknown state.
152 unsigned int reset_devices;
153 EXPORT_SYMBOL(reset_devices);
155 static int __init set_reset_devices(char *str)
161 __setup("reset_devices", set_reset_devices);
163 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
164 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
165 static const char *panic_later, *panic_param;
167 extern const struct obs_kernel_param __setup_start[], __setup_end[];
169 static int __init obsolete_checksetup(char *line)
171 const struct obs_kernel_param *p;
172 int had_early_param = 0;
176 int n = strlen(p->str);
177 if (parameqn(line, p->str, n)) {
179 /* Already done in parse_early_param?
180 * (Needs exact match on param part).
181 * Keep iterating, as we can have early
182 * params and __setups of same names 8( */
183 if (line[n] == '\0' || line[n] == '=')
185 } else if (!p->setup_func) {
186 pr_warn("Parameter %s is obsolete, ignored\n",
189 } else if (p->setup_func(line + n))
193 } while (p < __setup_end);
195 return had_early_param;
199 * This should be approx 2 Bo*oMips to start (note initial shift), and will
200 * still work even if initially too large, it will just take slightly longer
202 unsigned long loops_per_jiffy = (1<<12);
203 EXPORT_SYMBOL(loops_per_jiffy);
205 static int __init debug_kernel(char *str)
207 console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
211 static int __init quiet_kernel(char *str)
213 console_loglevel = CONSOLE_LOGLEVEL_QUIET;
217 early_param("debug", debug_kernel);
218 early_param("quiet", quiet_kernel);
220 static int __init loglevel(char *str)
225 * Only update loglevel value when a correct setting was passed,
226 * to prevent blind crashes (when loglevel being set to 0) that
227 * are quite hard to debug
229 if (get_option(&str, &newlevel)) {
230 console_loglevel = newlevel;
237 early_param("loglevel", loglevel);
239 /* Change NUL term back to "=", to make "param" the whole string. */
240 static int __init repair_env_string(char *param, char *val, const char *unused)
243 /* param=val or param="val"? */
244 if (val == param+strlen(param)+1)
246 else if (val == param+strlen(param)+2) {
248 memmove(val-1, val, strlen(val)+1);
256 /* Anything after -- gets handed straight to init. */
257 static int __init set_init_arg(char *param, char *val, const char *unused)
264 repair_env_string(param, val, unused);
266 for (i = 0; argv_init[i]; i++) {
267 if (i == MAX_INIT_ARGS) {
268 panic_later = "init";
273 argv_init[i] = param;
278 * Unknown boot options get handed to init, unless they look like
279 * unused parameters (modprobe will find them in /proc/cmdline).
281 static int __init unknown_bootoption(char *param, char *val, const char *unused)
283 repair_env_string(param, val, unused);
285 /* Handle obsolete-style parameters */
286 if (obsolete_checksetup(param))
289 /* Unused module parameter. */
290 if (strchr(param, '.') && (!val || strchr(param, '.') < val))
297 /* Environment option */
299 for (i = 0; envp_init[i]; i++) {
300 if (i == MAX_INIT_ENVS) {
304 if (!strncmp(param, envp_init[i], val - param))
307 envp_init[i] = param;
309 /* Command line option */
311 for (i = 0; argv_init[i]; i++) {
312 if (i == MAX_INIT_ARGS) {
313 panic_later = "init";
317 argv_init[i] = param;
322 static int __init init_setup(char *str)
326 execute_command = str;
328 * In case LILO is going to boot us with default command line,
329 * it prepends "auto" before the whole cmdline which makes
330 * the shell think it should execute a script with such name.
331 * So we ignore all arguments entered _before_ init=... [MJ]
333 for (i = 1; i < MAX_INIT_ARGS; i++)
337 __setup("init=", init_setup);
339 static int __init rdinit_setup(char *str)
343 ramdisk_execute_command = str;
344 /* See "auto" comment in init_setup */
345 for (i = 1; i < MAX_INIT_ARGS; i++)
349 __setup("rdinit=", rdinit_setup);
352 static const unsigned int setup_max_cpus = NR_CPUS;
353 #ifdef CONFIG_X86_LOCAL_APIC
354 static void __init smp_init(void)
356 APIC_init_uniprocessor();
359 #define smp_init() do { } while (0)
362 static inline void setup_nr_cpu_ids(void) { }
363 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
367 * We need to store the untouched command line for future reference.
368 * We also need to store the touched command line since the parameter
369 * parsing is performed in place, and we should allow a component to
370 * store reference of name/value for future reference.
372 static void __init setup_command_line(char *command_line)
375 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
376 initcall_command_line =
377 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
378 static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0);
379 strcpy(saved_command_line, boot_command_line);
380 strcpy(static_command_line, command_line);
384 * We need to finalize in a non-__init function or else race conditions
385 * between the root thread and the init thread may cause start_kernel to
386 * be reaped by free_initmem before the root thread has proceeded to
389 * gcc-3.4 accidentally inlines this function, so use noinline.
392 static __initdata DECLARE_COMPLETION(kthreadd_done);
394 static noinline void __init_refok rest_init(void)
398 rcu_scheduler_starting();
400 * We need to spawn init first so that it obtains pid 1, however
401 * the init task will end up wanting to create kthreads, which, if
402 * we schedule it before we create kthreadd, will OOPS.
404 kernel_thread(kernel_init, NULL, CLONE_FS);
405 numa_default_policy();
406 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
408 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
410 complete(&kthreadd_done);
413 * The boot idle thread must execute schedule()
414 * at least once to get things moving:
416 init_idle_bootup_task(current);
417 schedule_preempt_disabled();
418 /* Call into cpu_idle with preempt disabled */
419 cpu_startup_entry(CPUHP_ONLINE);
422 /* Check for early params. */
423 static int __init do_early_param(char *param, char *val, const char *unused)
425 const struct obs_kernel_param *p;
427 for (p = __setup_start; p < __setup_end; p++) {
428 if ((p->early && parameq(param, p->str)) ||
429 (strcmp(param, "console") == 0 &&
430 strcmp(p->str, "earlycon") == 0)
432 if (p->setup_func(val) != 0)
433 pr_warn("Malformed early option '%s'\n", param);
436 /* We accept everything at this stage. */
440 void __init parse_early_options(char *cmdline)
442 parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
445 /* Arch code calls this early on, or if not, just before other parsing. */
446 void __init parse_early_param(void)
448 static int done __initdata;
449 static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
454 /* All fall through to do_early_param. */
455 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
456 parse_early_options(tmp_cmdline);
461 * Activate the first processor.
464 static void __init boot_cpu_init(void)
466 int cpu = smp_processor_id();
467 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
468 set_cpu_online(cpu, true);
469 set_cpu_active(cpu, true);
470 set_cpu_present(cpu, true);
471 set_cpu_possible(cpu, true);
474 void __init __weak smp_setup_processor_id(void)
478 # if THREAD_SIZE >= PAGE_SIZE
479 void __init __weak thread_info_cache_init(void)
485 * Set up kernel memory allocators
487 static void __init mm_init(void)
490 * page_ext requires contiguous pages,
491 * bigger than MAX_ORDER unless SPARSEMEM.
493 page_ext_init_flatmem();
501 asmlinkage __visible void __init start_kernel(void)
507 * Need to run as early as possible, to initialize the
511 set_task_stack_end_magic(&init_task);
512 smp_setup_processor_id();
513 debug_objects_early_init();
516 * Set up the the initial canary ASAP:
518 boot_init_stack_canary();
523 early_boot_irqs_disabled = true;
526 * Interrupts are still disabled. Do necessary setups, then
531 pr_notice("%s", linux_banner);
532 setup_arch(&command_line);
533 mm_init_cpumask(&init_mm);
534 setup_command_line(command_line);
536 setup_per_cpu_areas();
537 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
539 build_all_zonelists(NULL, NULL);
542 pr_notice("Kernel command line: %s\n", boot_command_line);
544 after_dashes = parse_args("Booting kernel",
545 static_command_line, __start___param,
546 __stop___param - __start___param,
547 -1, -1, &unknown_bootoption);
548 if (!IS_ERR_OR_NULL(after_dashes))
549 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
555 * These use large bootmem allocations and must precede
560 vfs_caches_init_early();
566 * Set up the scheduler prior starting any interrupts (such as the
567 * timer interrupt). Full topology setup happens at smp_init()
568 * time - but meanwhile we still have a functioning scheduler.
572 * Disable preemption - early bootup scheduling is extremely
573 * fragile until we cpu_idle() for the first time.
576 if (WARN(!irqs_disabled(),
577 "Interrupts were enabled *very* early, fixing it\n"))
582 /* trace_printk() and trace points may be used after this */
585 context_tracking_init();
587 /* init some links before init_ISA_irqs() */
597 sched_clock_postinit();
600 call_function_init();
601 WARN(!irqs_disabled(), "Interrupts were enabled early\n");
602 early_boot_irqs_disabled = false;
605 kmem_cache_init_late();
608 * HACK ALERT! This is early. We're enabling the console before
609 * we've done PCI setups etc, and console_init() must be aware of
610 * this. But we do want output early, in case something goes wrong.
614 panic("Too many boot %s vars at `%s'", panic_later,
620 * Need to run this when irqs are enabled, because it wants
621 * to self-test [hard/soft]-irqs on/off lock inversion bugs
626 #ifdef CONFIG_BLK_DEV_INITRD
627 if (initrd_start && !initrd_below_start_ok &&
628 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
629 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
630 page_to_pfn(virt_to_page((void *)initrd_start)),
636 debug_objects_mem_init();
638 setup_per_cpu_pageset();
648 if (efi_enabled(EFI_RUNTIME_SERVICES))
649 efi_enter_virtual_mode();
651 #ifdef CONFIG_X86_ESPFIX64
652 /* Should be run before the first non-init thread is created */
655 thread_info_cache_init();
657 fork_init(totalram_pages);
663 vfs_caches_init(totalram_pages);
665 /* rootfs populating might need page-writeback */
666 page_writeback_init();
670 taskstats_init_early();
677 if (efi_enabled(EFI_RUNTIME_SERVICES)) {
679 efi_free_boot_services();
684 /* Do the rest non-__init'ed, we're now alive */
688 /* Call all constructor functions linked into the kernel. */
689 static void __init do_ctors(void)
691 #ifdef CONFIG_CONSTRUCTORS
692 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
694 for (; fn < (ctor_fn_t *) __ctors_end; fn++)
700 core_param(initcall_debug, initcall_debug, bool, 0644);
702 #ifdef CONFIG_KALLSYMS
703 struct blacklist_entry {
704 struct list_head next;
708 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
710 static int __init initcall_blacklist(char *str)
713 struct blacklist_entry *entry;
715 /* str argument is a comma-separated list of functions */
717 str_entry = strsep(&str, ",");
719 pr_debug("blacklisting initcall %s\n", str_entry);
720 entry = alloc_bootmem(sizeof(*entry));
721 entry->buf = alloc_bootmem(strlen(str_entry) + 1);
722 strcpy(entry->buf, str_entry);
723 list_add(&entry->next, &blacklisted_initcalls);
730 static bool __init_or_module initcall_blacklisted(initcall_t fn)
732 struct list_head *tmp;
733 struct blacklist_entry *entry;
736 fn_name = kasprintf(GFP_KERNEL, "%pf", fn);
740 list_for_each(tmp, &blacklisted_initcalls) {
741 entry = list_entry(tmp, struct blacklist_entry, next);
742 if (!strcmp(fn_name, entry->buf)) {
743 pr_debug("initcall %s blacklisted\n", fn_name);
753 static int __init initcall_blacklist(char *str)
755 pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
759 static bool __init_or_module initcall_blacklisted(initcall_t fn)
764 __setup("initcall_blacklist=", initcall_blacklist);
766 static int __init_or_module do_one_initcall_debug(initcall_t fn)
768 ktime_t calltime, delta, rettime;
769 unsigned long long duration;
772 printk(KERN_DEBUG "calling %pF @ %i\n", fn, task_pid_nr(current));
773 calltime = ktime_get();
775 rettime = ktime_get();
776 delta = ktime_sub(rettime, calltime);
777 duration = (unsigned long long) ktime_to_ns(delta) >> 10;
778 printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
784 int __init_or_module do_one_initcall(initcall_t fn)
786 int count = preempt_count();
790 if (initcall_blacklisted(fn))
794 ret = do_one_initcall_debug(fn);
800 if (preempt_count() != count) {
801 sprintf(msgbuf, "preemption imbalance ");
802 preempt_count_set(count);
804 if (irqs_disabled()) {
805 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
808 WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
814 extern initcall_t __initcall_start[];
815 extern initcall_t __initcall0_start[];
816 extern initcall_t __initcall1_start[];
817 extern initcall_t __initcall2_start[];
818 extern initcall_t __initcall3_start[];
819 extern initcall_t __initcall4_start[];
820 extern initcall_t __initcall5_start[];
821 extern initcall_t __initcall6_start[];
822 extern initcall_t __initcall7_start[];
823 extern initcall_t __initcall_end[];
825 static initcall_t *initcall_levels[] __initdata = {
837 /* Keep these in sync with initcalls in include/linux/init.h */
838 static char *initcall_level_names[] __initdata = {
849 static void __init do_initcall_level(int level)
853 strcpy(initcall_command_line, saved_command_line);
854 parse_args(initcall_level_names[level],
855 initcall_command_line, __start___param,
856 __stop___param - __start___param,
860 for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
861 do_one_initcall(*fn);
864 static void __init do_initcalls(void)
868 for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
869 do_initcall_level(level);
873 * Ok, the machine is now initialized. None of the devices
874 * have been touched yet, but the CPU subsystem is up and
875 * running, and memory and process management works.
877 * Now we can finally start doing some real work..
879 static void __init do_basic_setup(void)
882 usermodehelper_init();
887 usermodehelper_enable();
889 random_int_secret_init();
892 static void __init do_pre_smp_initcalls(void)
896 for (fn = __initcall_start; fn < __initcall0_start; fn++)
897 do_one_initcall(*fn);
901 * This function requests modules which should be loaded by default and is
902 * called twice right after initrd is mounted and right before init is
903 * exec'd. If such modules are on either initrd or rootfs, they will be
904 * loaded before control is passed to userland.
906 void __init load_default_modules(void)
908 load_default_elevator_module();
911 static int run_init_process(const char *init_filename)
913 argv_init[0] = init_filename;
914 return do_execve(getname_kernel(init_filename),
915 (const char __user *const __user *)argv_init,
916 (const char __user *const __user *)envp_init);
919 static int try_to_run_init_process(const char *init_filename)
923 ret = run_init_process(init_filename);
925 if (ret && ret != -ENOENT) {
926 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
933 static noinline void __init kernel_init_freeable(void);
935 static int __ref kernel_init(void *unused)
939 kernel_init_freeable();
940 /* need to finish all async __init code before freeing the memory */
941 async_synchronize_full();
944 system_state = SYSTEM_RUNNING;
945 numa_default_policy();
947 flush_delayed_fput();
949 if (ramdisk_execute_command) {
950 ret = run_init_process(ramdisk_execute_command);
953 pr_err("Failed to execute %s (error %d)\n",
954 ramdisk_execute_command, ret);
958 * We try each of these until one succeeds.
960 * The Bourne shell can be used instead of init if we are
961 * trying to recover a really broken machine.
963 if (execute_command) {
964 ret = run_init_process(execute_command);
967 #ifndef CONFIG_INIT_FALLBACK
968 panic("Requested init %s failed (error %d).",
969 execute_command, ret);
971 pr_err("Failed to execute %s (error %d). Attempting defaults...\n",
972 execute_command, ret);
975 if (!try_to_run_init_process("/sbin/init") ||
976 !try_to_run_init_process("/etc/init") ||
977 !try_to_run_init_process("/bin/init") ||
978 !try_to_run_init_process("/bin/sh"))
981 panic("No working init found. Try passing init= option to kernel. "
982 "See Linux Documentation/init.txt for guidance.");
985 static noinline void __init kernel_init_freeable(void)
988 * Wait until kthreadd is all set-up.
990 wait_for_completion(&kthreadd_done);
992 /* Now the scheduler is fully set up and can do blocking allocations */
993 gfp_allowed_mask = __GFP_BITS_MASK;
996 * init can allocate pages on any node
998 set_mems_allowed(node_states[N_MEMORY]);
1000 * init can run on any cpu.
1002 set_cpus_allowed_ptr(current, cpu_all_mask);
1004 cad_pid = task_pid(current);
1006 smp_prepare_cpus(setup_max_cpus);
1008 do_pre_smp_initcalls();
1009 lockup_detector_init();
1016 /* Open the /dev/console on the rootfs, this should never fail */
1017 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1018 pr_err("Warning: unable to open an initial console.\n");
1023 * check if there is an early userspace init. If yes, let it do all
1027 if (!ramdisk_execute_command)
1028 ramdisk_execute_command = "/init";
1030 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
1031 ramdisk_execute_command = NULL;
1032 prepare_namespace();
1036 * Ok, we have completed the initial bootup, and
1037 * we're essentially up and running. Get rid of the
1038 * initmem segments and start the user-mode stuff..
1040 * rootfs is available now, try loading the public keys
1041 * and default modules
1044 integrity_load_keys();
1045 load_default_modules();