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 #include <linux/types.h>
13 #include <linux/module.h>
14 #include <linux/proc_fs.h>
15 #include <linux/kernel.h>
16 #include <linux/syscalls.h>
17 #include <linux/stackprotector.h>
18 #include <linux/string.h>
19 #include <linux/ctype.h>
20 #include <linux/delay.h>
21 #include <linux/ioport.h>
22 #include <linux/init.h>
23 #include <linux/smp_lock.h>
24 #include <linux/initrd.h>
25 #include <linux/bootmem.h>
26 #include <linux/acpi.h>
27 #include <linux/tty.h>
28 #include <linux/percpu.h>
29 #include <linux/kmod.h>
30 #include <linux/vmalloc.h>
31 #include <linux/kernel_stat.h>
32 #include <linux/start_kernel.h>
33 #include <linux/security.h>
34 #include <linux/smp.h>
35 #include <linux/workqueue.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_cgroup.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/ftrace.h>
66 #include <linux/async.h>
67 #include <linux/kmemcheck.h>
68 #include <linux/kmemtrace.h>
69 #include <linux/sfi.h>
70 #include <linux/shmem_fs.h>
71 #include <linux/slab.h>
72 #include <trace/boot.h>
76 #include <asm/setup.h>
77 #include <asm/sections.h>
78 #include <asm/cacheflush.h>
80 #ifdef CONFIG_X86_LOCAL_APIC
84 static int kernel_init(void *);
86 extern void init_IRQ(void);
87 extern void fork_init(unsigned long);
88 extern void mca_init(void);
89 extern void sbus_init(void);
90 extern void prio_tree_init(void);
91 extern void radix_tree_init(void);
92 extern void free_initmem(void);
93 #ifndef CONFIG_DEBUG_RODATA
94 static inline void mark_rodata_ro(void) { }
98 extern void tc_init(void);
101 enum system_states system_state __read_mostly;
102 EXPORT_SYMBOL(system_state);
105 * Boot command-line arguments
107 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
108 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
110 extern void time_init(void);
111 /* Default late time init is NULL. archs can override this later. */
112 void (*__initdata late_time_init)(void);
113 extern void softirq_init(void);
115 /* Untouched command line saved by arch-specific code. */
116 char __initdata boot_command_line[COMMAND_LINE_SIZE];
117 /* Untouched saved command line (eg. for /proc) */
118 char *saved_command_line;
119 /* Command line for parameter parsing */
120 static char *static_command_line;
122 static char *execute_command;
123 static char *ramdisk_execute_command;
126 /* Setup configured maximum number of CPUs to activate */
127 unsigned int __initdata setup_max_cpus = NR_CPUS;
130 * Setup routine for controlling SMP activation
132 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
133 * activation entirely (the MPS table probe still happens, though).
135 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
136 * greater than 0, limits the maximum number of CPUs activated in
140 void __weak arch_disable_smp_support(void) { }
142 static int __init nosmp(char *str)
145 arch_disable_smp_support();
150 early_param("nosmp", nosmp);
152 /* this is hard limit */
153 static int __init nrcpus(char *str)
157 get_option(&str, &nr_cpus);
158 if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
159 nr_cpu_ids = nr_cpus;
164 early_param("nr_cpus", nrcpus);
166 static int __init maxcpus(char *str)
168 get_option(&str, &setup_max_cpus);
169 if (setup_max_cpus == 0)
170 arch_disable_smp_support();
175 early_param("maxcpus", maxcpus);
177 static const unsigned int setup_max_cpus = NR_CPUS;
181 * If set, this is an indication to the drivers that reset the underlying
182 * device before going ahead with the initialization otherwise driver might
183 * rely on the BIOS and skip the reset operation.
185 * This is useful if kernel is booting in an unreliable environment.
186 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
187 * skipped and devices will be in unknown state.
189 unsigned int reset_devices;
190 EXPORT_SYMBOL(reset_devices);
192 static int __init set_reset_devices(char *str)
198 __setup("reset_devices", set_reset_devices);
200 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
201 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
202 static const char *panic_later, *panic_param;
204 extern struct obs_kernel_param __setup_start[], __setup_end[];
206 static int __init obsolete_checksetup(char *line)
208 struct obs_kernel_param *p;
209 int had_early_param = 0;
213 int n = strlen(p->str);
214 if (!strncmp(line, p->str, n)) {
216 /* Already done in parse_early_param?
217 * (Needs exact match on param part).
218 * Keep iterating, as we can have early
219 * params and __setups of same names 8( */
220 if (line[n] == '\0' || line[n] == '=')
222 } else if (!p->setup_func) {
223 printk(KERN_WARNING "Parameter %s is obsolete,"
224 " ignored\n", p->str);
226 } else if (p->setup_func(line + n))
230 } while (p < __setup_end);
232 return had_early_param;
236 * This should be approx 2 Bo*oMips to start (note initial shift), and will
237 * still work even if initially too large, it will just take slightly longer
239 unsigned long loops_per_jiffy = (1<<12);
241 EXPORT_SYMBOL(loops_per_jiffy);
243 static int __init debug_kernel(char *str)
245 console_loglevel = 10;
249 static int __init quiet_kernel(char *str)
251 console_loglevel = 4;
255 early_param("debug", debug_kernel);
256 early_param("quiet", quiet_kernel);
258 static int __init loglevel(char *str)
260 get_option(&str, &console_loglevel);
264 early_param("loglevel", loglevel);
267 * Unknown boot options get handed to init, unless they look like
268 * unused parameters (modprobe will find them in /proc/cmdline).
270 static int __init unknown_bootoption(char *param, char *val)
272 /* Change NUL term back to "=", to make "param" the whole string. */
274 /* param=val or param="val"? */
275 if (val == param+strlen(param)+1)
277 else if (val == param+strlen(param)+2) {
279 memmove(val-1, val, strlen(val)+1);
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) {
301 panic_later = "Too many boot env vars at `%s'";
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 = "Too many boot init vars at `%s'";
317 argv_init[i] = param;
322 #ifdef CONFIG_DEBUG_PAGEALLOC
323 int __read_mostly debug_pagealloc_enabled = 0;
326 static int __init init_setup(char *str)
330 execute_command = str;
332 * In case LILO is going to boot us with default command line,
333 * it prepends "auto" before the whole cmdline which makes
334 * the shell think it should execute a script with such name.
335 * So we ignore all arguments entered _before_ init=... [MJ]
337 for (i = 1; i < MAX_INIT_ARGS; i++)
341 __setup("init=", init_setup);
343 static int __init rdinit_setup(char *str)
347 ramdisk_execute_command = str;
348 /* See "auto" comment in init_setup */
349 for (i = 1; i < MAX_INIT_ARGS; i++)
353 __setup("rdinit=", rdinit_setup);
357 #ifdef CONFIG_X86_LOCAL_APIC
358 static void __init smp_init(void)
360 APIC_init_uniprocessor();
363 #define smp_init() do { } while (0)
366 static inline void setup_nr_cpu_ids(void) { }
367 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
371 /* Setup number of possible processor ids */
372 int nr_cpu_ids __read_mostly = NR_CPUS;
373 EXPORT_SYMBOL(nr_cpu_ids);
375 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
376 static void __init setup_nr_cpu_ids(void)
378 nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
381 /* Called by boot processor to activate the rest. */
382 static void __init smp_init(void)
386 /* FIXME: This should be done in userspace --RR */
387 for_each_present_cpu(cpu) {
388 if (num_online_cpus() >= setup_max_cpus)
390 if (!cpu_online(cpu))
394 /* Any cleanup work */
395 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
396 smp_cpus_done(setup_max_cpus);
402 * We need to store the untouched command line for future reference.
403 * We also need to store the touched command line since the parameter
404 * parsing is performed in place, and we should allow a component to
405 * store reference of name/value for future reference.
407 static void __init setup_command_line(char *command_line)
409 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
410 static_command_line = alloc_bootmem(strlen (command_line)+1);
411 strcpy (saved_command_line, boot_command_line);
412 strcpy (static_command_line, command_line);
416 * We need to finalize in a non-__init function or else race conditions
417 * between the root thread and the init thread may cause start_kernel to
418 * be reaped by free_initmem before the root thread has proceeded to
421 * gcc-3.4 accidentally inlines this function, so use noinline.
424 static noinline void __init_refok rest_init(void)
425 __releases(kernel_lock)
429 rcu_scheduler_starting();
430 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
431 numa_default_policy();
432 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
434 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
439 * The boot idle thread must execute schedule()
440 * at least once to get things moving:
442 init_idle_bootup_task(current);
443 preempt_enable_no_resched();
447 /* Call into cpu_idle with preempt disabled */
451 /* Check for early params. */
452 static int __init do_early_param(char *param, char *val)
454 struct obs_kernel_param *p;
456 for (p = __setup_start; p < __setup_end; p++) {
457 if ((p->early && strcmp(param, p->str) == 0) ||
458 (strcmp(param, "console") == 0 &&
459 strcmp(p->str, "earlycon") == 0)
461 if (p->setup_func(val) != 0)
463 "Malformed early option '%s'\n", param);
466 /* We accept everything at this stage. */
470 void __init parse_early_options(char *cmdline)
472 parse_args("early options", cmdline, NULL, 0, do_early_param);
475 /* Arch code calls this early on, or if not, just before other parsing. */
476 void __init parse_early_param(void)
478 static __initdata int done = 0;
479 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
484 /* All fall through to do_early_param. */
485 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
486 parse_early_options(tmp_cmdline);
491 * Activate the first processor.
494 static void __init boot_cpu_init(void)
496 int cpu = smp_processor_id();
497 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
498 set_cpu_online(cpu, true);
499 set_cpu_active(cpu, true);
500 set_cpu_present(cpu, true);
501 set_cpu_possible(cpu, true);
504 void __init __weak smp_setup_processor_id(void)
508 void __init __weak thread_info_cache_init(void)
513 * Set up kernel memory allocators
515 static void __init mm_init(void)
518 * page_cgroup requires countinous pages as memmap
519 * and it's bigger than MAX_ORDER unless SPARSEMEM.
521 page_cgroup_init_flatmem();
524 pgtable_cache_init();
528 asmlinkage void __init start_kernel(void)
531 extern struct kernel_param __start___param[], __stop___param[];
533 smp_setup_processor_id();
536 * Need to run as early as possible, to initialize the
540 debug_objects_early_init();
543 * Set up the the initial canary ASAP:
545 boot_init_stack_canary();
550 early_boot_irqs_off();
551 early_init_irq_lock_class();
554 * Interrupts are still disabled. Do necessary setups, then
561 printk(KERN_NOTICE "%s", linux_banner);
562 setup_arch(&command_line);
563 mm_init_owner(&init_mm, &init_task);
564 setup_command_line(command_line);
566 setup_per_cpu_areas();
567 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
569 build_all_zonelists();
572 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
574 parse_args("Booting kernel", static_command_line, __start___param,
575 __stop___param - __start___param,
576 &unknown_bootoption);
578 * These use large bootmem allocations and must precede
582 vfs_caches_init_early();
587 * Set up the scheduler prior starting any interrupts (such as the
588 * timer interrupt). Full topology setup happens at smp_init()
589 * time - but meanwhile we still have a functioning scheduler.
593 * Disable preemption - early bootup scheduling is extremely
594 * fragile until we cpu_idle() for the first time.
597 if (!irqs_disabled()) {
598 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
599 "enabled *very* early, fixing it\n");
604 /* init some links before init_ISA_irqs() */
614 if (!irqs_disabled())
615 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
617 early_boot_irqs_on();
620 /* Interrupts are enabled now so all GFP allocations are safe. */
621 gfp_allowed_mask = __GFP_BITS_MASK;
623 kmem_cache_init_late();
626 * HACK ALERT! This is early. We're enabling the console before
627 * we've done PCI setups etc, and console_init() must be aware of
628 * this. But we do want output early, in case something goes wrong.
632 panic(panic_later, panic_param);
637 * Need to run this when irqs are enabled, because it wants
638 * to self-test [hard/soft]-irqs on/off lock inversion bugs
643 #ifdef CONFIG_BLK_DEV_INITRD
644 if (initrd_start && !initrd_below_start_ok &&
645 page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
646 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
648 page_to_pfn(virt_to_page((void *)initrd_start)),
654 enable_debug_pagealloc();
657 debug_objects_mem_init();
659 setup_per_cpu_pageset();
669 efi_enter_virtual_mode();
671 thread_info_cache_init();
673 fork_init(totalram_pages);
678 vfs_caches_init(totalram_pages);
680 /* rootfs populating might need page-writeback */
681 page_writeback_init();
682 #ifdef CONFIG_PROC_FS
687 taskstats_init_early();
692 acpi_early_init(); /* before LAPIC and SMP init */
697 /* Do the rest non-__init'ed, we're now alive */
701 /* Call all constructor functions linked into the kernel. */
702 static void __init do_ctors(void)
704 #ifdef CONFIG_CONSTRUCTORS
705 ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
707 for (; fn < (ctor_fn_t *) __ctors_end; fn++)
713 core_param(initcall_debug, initcall_debug, bool, 0644);
715 static char msgbuf[64];
716 static struct boot_trace_call call;
717 static struct boot_trace_ret ret;
719 int do_one_initcall(initcall_t fn)
721 int count = preempt_count();
722 ktime_t calltime, delta, rettime;
724 if (initcall_debug) {
725 call.caller = task_pid_nr(current);
726 printk("calling %pF @ %i\n", fn, call.caller);
727 calltime = ktime_get();
728 trace_boot_call(&call, fn);
734 if (initcall_debug) {
735 disable_boot_trace();
736 rettime = ktime_get();
737 delta = ktime_sub(rettime, calltime);
738 ret.duration = (unsigned long long) ktime_to_ns(delta) >> 10;
739 trace_boot_ret(&ret, fn);
740 printk("initcall %pF returned %d after %Ld usecs\n", fn,
741 ret.result, ret.duration);
746 if (ret.result && ret.result != -ENODEV && initcall_debug)
747 sprintf(msgbuf, "error code %d ", ret.result);
749 if (preempt_count() != count) {
750 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
751 preempt_count() = count;
753 if (irqs_disabled()) {
754 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
758 printk("initcall %pF returned with %s\n", fn, msgbuf);
765 extern initcall_t __initcall_start[], __initcall_end[], __early_initcall_end[];
767 static void __init do_initcalls(void)
771 for (fn = __early_initcall_end; fn < __initcall_end; fn++)
772 do_one_initcall(*fn);
774 /* Make sure there is no pending stuff from the initcall sequence */
775 flush_scheduled_work();
779 * Ok, the machine is now initialized. None of the devices
780 * have been touched yet, but the CPU subsystem is up and
781 * running, and memory and process management works.
783 * Now we can finally start doing some real work..
785 static void __init do_basic_setup(void)
789 usermodehelper_init();
797 static void __init do_pre_smp_initcalls(void)
801 for (fn = __initcall_start; fn < __early_initcall_end; fn++)
802 do_one_initcall(*fn);
805 static void run_init_process(char *init_filename)
807 argv_init[0] = init_filename;
808 kernel_execve(init_filename, argv_init, envp_init);
811 /* This is a non __init function. Force it to be noinline otherwise gcc
812 * makes it inline to init() and it becomes part of init.text section
814 static noinline int init_post(void)
815 __releases(kernel_lock)
817 /* need to finish all async __init code before freeing the memory */
818 async_synchronize_full();
822 system_state = SYSTEM_RUNNING;
823 numa_default_policy();
826 current->signal->flags |= SIGNAL_UNKILLABLE;
828 if (ramdisk_execute_command) {
829 run_init_process(ramdisk_execute_command);
830 printk(KERN_WARNING "Failed to execute %s\n",
831 ramdisk_execute_command);
835 * We try each of these until one succeeds.
837 * The Bourne shell can be used instead of init if we are
838 * trying to recover a really broken machine.
840 if (execute_command) {
841 run_init_process(execute_command);
842 printk(KERN_WARNING "Failed to execute %s. Attempting "
843 "defaults...\n", execute_command);
845 run_init_process("/sbin/init");
846 run_init_process("/etc/init");
847 run_init_process("/bin/init");
848 run_init_process("/bin/sh");
850 panic("No init found. Try passing init= option to kernel. "
851 "See Linux Documentation/init.txt for guidance.");
854 static int __init kernel_init(void * unused)
859 * init can allocate pages on any node
861 set_mems_allowed(node_states[N_HIGH_MEMORY]);
863 * init can run on any cpu.
865 set_cpus_allowed_ptr(current, cpu_all_mask);
867 * Tell the world that we're going to be the grim
868 * reaper of innocent orphaned children.
870 * We don't want people to have to make incorrect
871 * assumptions about where in the task array this
874 init_pid_ns.child_reaper = current;
876 cad_pid = task_pid(current);
878 smp_prepare_cpus(setup_max_cpus);
880 do_pre_smp_initcalls();
888 /* Open the /dev/console on the rootfs, this should never fail */
889 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
890 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
895 * check if there is an early userspace init. If yes, let it do all
899 if (!ramdisk_execute_command)
900 ramdisk_execute_command = "/init";
902 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
903 ramdisk_execute_command = NULL;
908 * Ok, we have completed the initial bootup, and
909 * we're essentially up and running. Get rid of the
910 * initmem segments and start the user-mode stuff..