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/string.h>
18 #include <linux/ctype.h>
19 #include <linux/delay.h>
20 #include <linux/utsname.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/hdreg.h>
26 #include <linux/bootmem.h>
27 #include <linux/tty.h>
28 #include <linux/gfp.h>
29 #include <linux/percpu.h>
30 #include <linux/kmod.h>
31 #include <linux/kernel_stat.h>
32 #include <linux/start_kernel.h>
33 #include <linux/security.h>
34 #include <linux/workqueue.h>
35 #include <linux/profile.h>
36 #include <linux/rcupdate.h>
37 #include <linux/moduleparam.h>
38 #include <linux/kallsyms.h>
39 #include <linux/writeback.h>
40 #include <linux/cpu.h>
41 #include <linux/cpuset.h>
42 #include <linux/cgroup.h>
43 #include <linux/efi.h>
44 #include <linux/tick.h>
45 #include <linux/interrupt.h>
46 #include <linux/taskstats_kern.h>
47 #include <linux/delayacct.h>
48 #include <linux/unistd.h>
49 #include <linux/rmap.h>
50 #include <linux/mempolicy.h>
51 #include <linux/key.h>
52 #include <linux/unwind.h>
53 #include <linux/buffer_head.h>
54 #include <linux/debug_locks.h>
55 #include <linux/debugobjects.h>
56 #include <linux/lockdep.h>
57 #include <linux/pid_namespace.h>
58 #include <linux/device.h>
59 #include <linux/kthread.h>
60 #include <linux/sched.h>
61 #include <linux/signal.h>
62 #include <linux/idr.h>
66 #include <asm/setup.h>
67 #include <asm/sections.h>
68 #include <asm/cacheflush.h>
70 #ifdef CONFIG_X86_LOCAL_APIC
75 * This is one of the first .c files built. Error out early if we have compiler
79 #if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0
80 #warning gcc-4.1.0 is known to miscompile the kernel. A different compiler version is recommended.
83 static int kernel_init(void *);
85 extern void init_IRQ(void);
86 extern void fork_init(unsigned long);
87 extern void mca_init(void);
88 extern void sbus_init(void);
89 extern void pidhash_init(void);
90 extern void pidmap_init(void);
91 extern void prio_tree_init(void);
92 extern void radix_tree_init(void);
93 extern void free_initmem(void);
95 extern void acpi_early_init(void);
97 static inline void acpi_early_init(void) { }
99 #ifndef CONFIG_DEBUG_RODATA
100 static inline void mark_rodata_ro(void) { }
104 extern void tc_init(void);
107 enum system_states system_state;
108 EXPORT_SYMBOL(system_state);
111 * Boot command-line arguments
113 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
114 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
116 extern void time_init(void);
117 /* Default late time init is NULL. archs can override this later. */
118 void (*late_time_init)(void);
119 extern void softirq_init(void);
121 /* Untouched command line saved by arch-specific code. */
122 char __initdata boot_command_line[COMMAND_LINE_SIZE];
123 /* Untouched saved command line (eg. for /proc) */
124 char *saved_command_line;
125 /* Command line for parameter parsing */
126 static char *static_command_line;
128 static char *execute_command;
129 static char *ramdisk_execute_command;
132 /* Setup configured maximum number of CPUs to activate */
133 unsigned int __initdata setup_max_cpus = NR_CPUS;
136 * Setup routine for controlling SMP activation
138 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
139 * activation entirely (the MPS table probe still happens, though).
141 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
142 * greater than 0, limits the maximum number of CPUs activated in
145 #ifndef CONFIG_X86_IO_APIC
146 static inline void disable_ioapic_setup(void) {};
149 static int __init nosmp(char *str)
152 disable_ioapic_setup();
156 early_param("nosmp", nosmp);
158 static int __init maxcpus(char *str)
160 get_option(&str, &setup_max_cpus);
161 if (setup_max_cpus == 0)
162 disable_ioapic_setup();
167 early_param("maxcpus", maxcpus);
169 #define setup_max_cpus NR_CPUS
173 * If set, this is an indication to the drivers that reset the underlying
174 * device before going ahead with the initialization otherwise driver might
175 * rely on the BIOS and skip the reset operation.
177 * This is useful if kernel is booting in an unreliable environment.
178 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
179 * skipped and devices will be in unknown state.
181 unsigned int reset_devices;
182 EXPORT_SYMBOL(reset_devices);
184 static int __init set_reset_devices(char *str)
190 __setup("reset_devices", set_reset_devices);
192 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
193 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
194 static const char *panic_later, *panic_param;
196 extern struct obs_kernel_param __setup_start[], __setup_end[];
198 static int __init obsolete_checksetup(char *line)
200 struct obs_kernel_param *p;
201 int had_early_param = 0;
205 int n = strlen(p->str);
206 if (!strncmp(line, p->str, n)) {
208 /* Already done in parse_early_param?
209 * (Needs exact match on param part).
210 * Keep iterating, as we can have early
211 * params and __setups of same names 8( */
212 if (line[n] == '\0' || line[n] == '=')
214 } else if (!p->setup_func) {
215 printk(KERN_WARNING "Parameter %s is obsolete,"
216 " ignored\n", p->str);
218 } else if (p->setup_func(line + n))
222 } while (p < __setup_end);
224 return had_early_param;
228 * This should be approx 2 Bo*oMips to start (note initial shift), and will
229 * still work even if initially too large, it will just take slightly longer
231 unsigned long loops_per_jiffy = (1<<12);
233 EXPORT_SYMBOL(loops_per_jiffy);
235 static int __init debug_kernel(char *str)
237 console_loglevel = 10;
241 static int __init quiet_kernel(char *str)
243 console_loglevel = 4;
247 early_param("debug", debug_kernel);
248 early_param("quiet", quiet_kernel);
250 static int __init loglevel(char *str)
252 get_option(&str, &console_loglevel);
256 early_param("loglevel", loglevel);
259 * Unknown boot options get handed to init, unless they look like
262 static int __init unknown_bootoption(char *param, char *val)
264 /* Change NUL term back to "=", to make "param" the whole string. */
266 /* param=val or param="val"? */
267 if (val == param+strlen(param)+1)
269 else if (val == param+strlen(param)+2) {
271 memmove(val-1, val, strlen(val)+1);
277 /* Handle obsolete-style parameters */
278 if (obsolete_checksetup(param))
282 * Preemptive maintenance for "why didn't my misspelled command
285 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
286 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
294 /* Environment option */
296 for (i = 0; envp_init[i]; i++) {
297 if (i == MAX_INIT_ENVS) {
298 panic_later = "Too many boot env vars at `%s'";
301 if (!strncmp(param, envp_init[i], val - param))
304 envp_init[i] = param;
306 /* Command line option */
308 for (i = 0; argv_init[i]; i++) {
309 if (i == MAX_INIT_ARGS) {
310 panic_later = "Too many boot init vars at `%s'";
314 argv_init[i] = param;
319 #ifdef CONFIG_DEBUG_PAGEALLOC
320 int __read_mostly debug_pagealloc_enabled = 0;
323 static int __init init_setup(char *str)
327 execute_command = str;
329 * In case LILO is going to boot us with default command line,
330 * it prepends "auto" before the whole cmdline which makes
331 * the shell think it should execute a script with such name.
332 * So we ignore all arguments entered _before_ init=... [MJ]
334 for (i = 1; i < MAX_INIT_ARGS; i++)
338 __setup("init=", init_setup);
340 static int __init rdinit_setup(char *str)
344 ramdisk_execute_command = str;
345 /* See "auto" comment in init_setup */
346 for (i = 1; i < MAX_INIT_ARGS; i++)
350 __setup("rdinit=", rdinit_setup);
354 #ifdef CONFIG_X86_LOCAL_APIC
355 static void __init smp_init(void)
357 APIC_init_uniprocessor();
360 #define smp_init() do { } while (0)
363 static inline void setup_per_cpu_areas(void) { }
364 static inline void setup_nr_cpu_ids(void) { }
365 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
369 #if NR_CPUS > BITS_PER_LONG
370 cpumask_t cpu_mask_all __read_mostly = CPU_MASK_ALL;
371 EXPORT_SYMBOL(cpu_mask_all);
374 /* Setup number of possible processor ids */
375 int nr_cpu_ids __read_mostly = NR_CPUS;
376 EXPORT_SYMBOL(nr_cpu_ids);
378 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
379 static void __init setup_nr_cpu_ids(void)
381 int cpu, highest_cpu = 0;
383 for_each_possible_cpu(cpu)
386 nr_cpu_ids = highest_cpu + 1;
389 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
390 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
392 EXPORT_SYMBOL(__per_cpu_offset);
394 static void __init setup_per_cpu_areas(void)
396 unsigned long size, i;
398 unsigned long nr_possible_cpus = num_possible_cpus();
400 /* Copy section for each CPU (we discard the original) */
401 size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
402 ptr = alloc_bootmem_pages(size * nr_possible_cpus);
404 for_each_possible_cpu(i) {
405 __per_cpu_offset[i] = ptr - __per_cpu_start;
406 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
410 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
412 /* Called by boot processor to activate the rest. */
413 static void __init smp_init(void)
417 /* FIXME: This should be done in userspace --RR */
418 for_each_present_cpu(cpu) {
419 if (num_online_cpus() >= setup_max_cpus)
421 if (!cpu_online(cpu))
425 /* Any cleanup work */
426 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
427 smp_cpus_done(setup_max_cpus);
433 * We need to store the untouched command line for future reference.
434 * We also need to store the touched command line since the parameter
435 * parsing is performed in place, and we should allow a component to
436 * store reference of name/value for future reference.
438 static void __init setup_command_line(char *command_line)
440 saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
441 static_command_line = alloc_bootmem(strlen (command_line)+1);
442 strcpy (saved_command_line, boot_command_line);
443 strcpy (static_command_line, command_line);
447 * We need to finalize in a non-__init function or else race conditions
448 * between the root thread and the init thread may cause start_kernel to
449 * be reaped by free_initmem before the root thread has proceeded to
452 * gcc-3.4 accidentally inlines this function, so use noinline.
455 static void noinline __init_refok rest_init(void)
456 __releases(kernel_lock)
460 kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
461 numa_default_policy();
462 pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
463 kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
467 * The boot idle thread must execute schedule()
468 * at least once to get things moving:
470 init_idle_bootup_task(current);
471 preempt_enable_no_resched();
475 /* Call into cpu_idle with preempt disabled */
479 /* Check for early params. */
480 static int __init do_early_param(char *param, char *val)
482 struct obs_kernel_param *p;
484 for (p = __setup_start; p < __setup_end; p++) {
485 if ((p->early && strcmp(param, p->str) == 0) ||
486 (strcmp(param, "console") == 0 &&
487 strcmp(p->str, "earlycon") == 0)
489 if (p->setup_func(val) != 0)
491 "Malformed early option '%s'\n", param);
494 /* We accept everything at this stage. */
498 /* Arch code calls this early on, or if not, just before other parsing. */
499 void __init parse_early_param(void)
501 static __initdata int done = 0;
502 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
507 /* All fall through to do_early_param. */
508 strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
509 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
514 * Activate the first processor.
517 static void __init boot_cpu_init(void)
519 int cpu = smp_processor_id();
520 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
521 cpu_set(cpu, cpu_online_map);
522 cpu_set(cpu, cpu_present_map);
523 cpu_set(cpu, cpu_possible_map);
526 void __init __weak smp_setup_processor_id(void)
530 void __init __weak thread_info_cache_init(void)
534 asmlinkage void __init start_kernel(void)
537 extern struct kernel_param __start___param[], __stop___param[];
539 smp_setup_processor_id();
542 * Need to run as early as possible, to initialize the
547 debug_objects_early_init();
551 early_boot_irqs_off();
552 early_init_irq_lock_class();
555 * Interrupts are still disabled. Do necessary setups, then
563 printk(linux_banner);
564 setup_arch(&command_line);
565 mm_init_owner(&init_mm, &init_task);
566 setup_command_line(command_line);
568 setup_per_cpu_areas();
570 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
573 * Set up the scheduler prior starting any interrupts (such as the
574 * timer interrupt). Full topology setup happens at smp_init()
575 * time - but meanwhile we still have a functioning scheduler.
579 * Disable preemption - early bootup scheduling is extremely
580 * fragile until we cpu_idle() for the first time.
583 build_all_zonelists();
585 printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
587 parse_args("Booting kernel", static_command_line, __start___param,
588 __stop___param - __start___param,
589 &unknown_bootoption);
590 if (!irqs_disabled()) {
591 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
592 "enabled *very* early, fixing it\n");
607 if (!irqs_disabled())
608 printk("start_kernel(): bug: interrupts were enabled early\n");
609 early_boot_irqs_on();
613 * HACK ALERT! This is early. We're enabling the console before
614 * we've done PCI setups etc, and console_init() must be aware of
615 * this. But we do want output early, in case something goes wrong.
619 panic(panic_later, panic_param);
624 * Need to run this when irqs are enabled, because it wants
625 * to self-test [hard/soft]-irqs on/off lock inversion bugs
630 #ifdef CONFIG_BLK_DEV_INITRD
631 if (initrd_start && !initrd_below_start_ok &&
632 initrd_start < min_low_pfn << PAGE_SHIFT) {
633 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
634 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
638 vfs_caches_init_early();
641 enable_debug_pagealloc();
644 debug_objects_mem_init();
646 setup_per_cpu_pageset();
652 pgtable_cache_init();
657 efi_enter_virtual_mode();
659 thread_info_cache_init();
660 fork_init(num_physpages);
666 vfs_caches_init(num_physpages);
669 /* rootfs populating might need page-writeback */
670 page_writeback_init();
671 #ifdef CONFIG_PROC_FS
676 taskstats_init_early();
681 acpi_early_init(); /* before LAPIC and SMP init */
683 /* Do the rest non-__init'ed, we're now alive */
687 static int __initdata initcall_debug;
689 static int __init initcall_debug_setup(char *str)
694 __setup("initcall_debug", initcall_debug_setup);
696 static void __init do_one_initcall(initcall_t fn)
698 int count = preempt_count();
699 ktime_t t0, t1, delta;
703 if (initcall_debug) {
704 print_fn_descriptor_symbol("calling %s\n", fn);
710 if (initcall_debug) {
712 delta = ktime_sub(t1, t0);
714 print_fn_descriptor_symbol("initcall %s", fn);
715 printk(" returned %d after %Ld msecs\n", result,
716 (unsigned long long) delta.tv64 >> 20);
721 if (result && result != -ENODEV && initcall_debug)
722 sprintf(msgbuf, "error code %d ", result);
724 if (preempt_count() != count) {
725 strlcat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
726 preempt_count() = count;
728 if (irqs_disabled()) {
729 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
733 print_fn_descriptor_symbol(KERN_WARNING "initcall %s", fn);
734 printk(" returned with %s\n", msgbuf);
739 extern initcall_t __initcall_start[], __initcall_end[];
741 static void __init do_initcalls(void)
745 for (call = __initcall_start; call < __initcall_end; call++)
746 do_one_initcall(*call);
748 /* Make sure there is no pending stuff from the initcall sequence */
749 flush_scheduled_work();
753 * Ok, the machine is now initialized. None of the devices
754 * have been touched yet, but the CPU subsystem is up and
755 * running, and memory and process management works.
757 * Now we can finally start doing some real work..
759 static void __init do_basic_setup(void)
761 rcu_init_sched(); /* needed by module_init stage. */
762 /* drivers will send hotplug events */
764 usermodehelper_init();
770 static int __initdata nosoftlockup;
772 static int __init nosoftlockup_setup(char *str)
777 __setup("nosoftlockup", nosoftlockup_setup);
779 static void __init do_pre_smp_initcalls(void)
781 extern int spawn_ksoftirqd(void);
786 spawn_softlockup_task();
789 static void run_init_process(char *init_filename)
791 argv_init[0] = init_filename;
792 kernel_execve(init_filename, argv_init, envp_init);
795 /* This is a non __init function. Force it to be noinline otherwise gcc
796 * makes it inline to init() and it becomes part of init.text section
798 static int noinline init_post(void)
803 system_state = SYSTEM_RUNNING;
804 numa_default_policy();
806 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
807 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
812 current->signal->flags |= SIGNAL_UNKILLABLE;
814 if (ramdisk_execute_command) {
815 run_init_process(ramdisk_execute_command);
816 printk(KERN_WARNING "Failed to execute %s\n",
817 ramdisk_execute_command);
821 * We try each of these until one succeeds.
823 * The Bourne shell can be used instead of init if we are
824 * trying to recover a really broken machine.
826 if (execute_command) {
827 run_init_process(execute_command);
828 printk(KERN_WARNING "Failed to execute %s. Attempting "
829 "defaults...\n", execute_command);
831 run_init_process("/sbin/init");
832 run_init_process("/etc/init");
833 run_init_process("/bin/init");
834 run_init_process("/bin/sh");
836 panic("No init found. Try passing init= option to kernel.");
839 static int __init kernel_init(void * unused)
843 * init can run on any cpu.
845 set_cpus_allowed_ptr(current, CPU_MASK_ALL_PTR);
847 * Tell the world that we're going to be the grim
848 * reaper of innocent orphaned children.
850 * We don't want people to have to make incorrect
851 * assumptions about where in the task array this
854 init_pid_ns.child_reaper = current;
856 cad_pid = task_pid(current);
858 smp_prepare_cpus(setup_max_cpus);
860 do_pre_smp_initcalls();
870 * check if there is an early userspace init. If yes, let it do all
874 if (!ramdisk_execute_command)
875 ramdisk_execute_command = "/init";
877 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
878 ramdisk_execute_command = NULL;
883 * Ok, we have completed the initial bootup, and
884 * we're essentially up and running. Get rid of the
885 * initmem segments and start the user-mode stuff..