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/efi.h>
43 #include <linux/taskstats_kern.h>
44 #include <linux/delayacct.h>
45 #include <linux/unistd.h>
46 #include <linux/rmap.h>
47 #include <linux/mempolicy.h>
48 #include <linux/key.h>
49 #include <linux/unwind.h>
50 #include <linux/buffer_head.h>
51 #include <linux/debug_locks.h>
52 #include <linux/lockdep.h>
53 #include <linux/pid_namespace.h>
54 #include <linux/device.h>
55 #include <linux/vserver/percpu.h>
59 #include <asm/setup.h>
60 #include <asm/sections.h>
61 #include <asm/cacheflush.h>
63 #ifdef CONFIG_X86_LOCAL_APIC
68 * This is one of the first .c files built. Error out early if we have compiler
71 * Versions of gcc older than that listed below may actually compile and link
72 * okay, but the end product can have subtle run time bugs. To avoid associated
73 * bogus bug reports, we flatly refuse to compile with a gcc that is known to be
74 * too old from the very beginning.
76 #if (__GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 2)
77 #error Sorry, your GCC is too old. It builds incorrect kernels.
80 #if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0
81 #warning gcc-4.1.0 is known to miscompile the kernel. A different compiler version is recommended.
84 static int 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 sysctl_init(void);
91 extern void signals_init(void);
92 extern void pidhash_init(void);
93 extern void pidmap_init(void);
94 extern void prio_tree_init(void);
95 extern void radix_tree_init(void);
96 extern void free_initmem(void);
97 extern void prepare_namespace(void);
99 extern void acpi_early_init(void);
101 static inline void acpi_early_init(void) { }
103 #ifndef CONFIG_DEBUG_RODATA
104 static inline void mark_rodata_ro(void) { }
108 extern void tc_init(void);
111 enum system_states system_state;
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 (*late_time_init)(void);
123 extern void softirq_init(void);
125 /* Untouched command line (eg. for /proc) saved by arch-specific code. */
126 char saved_command_line[COMMAND_LINE_SIZE];
128 static char *execute_command;
129 static char *ramdisk_execute_command;
131 /* Setup configured maximum number of CPUs to activate */
132 static unsigned int max_cpus = NR_CPUS;
135 * If set, this is an indication to the drivers that reset the underlying
136 * device before going ahead with the initialization otherwise driver might
137 * rely on the BIOS and skip the reset operation.
139 * This is useful if kernel is booting in an unreliable environment.
140 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
141 * skipped and devices will be in unknown state.
143 unsigned int reset_devices;
144 EXPORT_SYMBOL(reset_devices);
147 * Setup routine for controlling SMP activation
149 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
150 * activation entirely (the MPS table probe still happens, though).
152 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
153 * greater than 0, limits the maximum number of CPUs activated in
156 static int __init nosmp(char *str)
162 __setup("nosmp", nosmp);
164 static int __init maxcpus(char *str)
166 get_option(&str, &max_cpus);
170 __setup("maxcpus=", maxcpus);
172 static int __init set_reset_devices(char *str)
178 __setup("reset_devices", set_reset_devices);
180 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
181 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
182 static const char *panic_later, *panic_param;
184 extern struct obs_kernel_param __setup_start[], __setup_end[];
186 static int __init obsolete_checksetup(char *line)
188 struct obs_kernel_param *p;
189 int had_early_param = 0;
193 int n = strlen(p->str);
194 if (!strncmp(line, p->str, n)) {
196 /* Already done in parse_early_param?
197 * (Needs exact match on param part).
198 * Keep iterating, as we can have early
199 * params and __setups of same names 8( */
200 if (line[n] == '\0' || line[n] == '=')
202 } else if (!p->setup_func) {
203 printk(KERN_WARNING "Parameter %s is obsolete,"
204 " ignored\n", p->str);
206 } else if (p->setup_func(line + n))
210 } while (p < __setup_end);
212 return had_early_param;
216 * This should be approx 2 Bo*oMips to start (note initial shift), and will
217 * still work even if initially too large, it will just take slightly longer
219 unsigned long loops_per_jiffy = (1<<12);
221 EXPORT_SYMBOL(loops_per_jiffy);
223 static int __init debug_kernel(char *str)
227 console_loglevel = 10;
231 static int __init quiet_kernel(char *str)
235 console_loglevel = 4;
239 __setup("debug", debug_kernel);
240 __setup("quiet", quiet_kernel);
242 static int __init loglevel(char *str)
244 get_option(&str, &console_loglevel);
248 __setup("loglevel=", loglevel);
251 * Unknown boot options get handed to init, unless they look like
254 static int __init unknown_bootoption(char *param, char *val)
256 /* Change NUL term back to "=", to make "param" the whole string. */
258 /* param=val or param="val"? */
259 if (val == param+strlen(param)+1)
261 else if (val == param+strlen(param)+2) {
263 memmove(val-1, val, strlen(val)+1);
269 /* Handle obsolete-style parameters */
270 if (obsolete_checksetup(param))
274 * Preemptive maintenance for "why didn't my mispelled command
277 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
278 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
286 /* Environment option */
288 for (i = 0; envp_init[i]; i++) {
289 if (i == MAX_INIT_ENVS) {
290 panic_later = "Too many boot env vars at `%s'";
293 if (!strncmp(param, envp_init[i], val - param))
296 envp_init[i] = param;
298 /* Command line option */
300 for (i = 0; argv_init[i]; i++) {
301 if (i == MAX_INIT_ARGS) {
302 panic_later = "Too many boot init vars at `%s'";
306 argv_init[i] = param;
311 static int __init init_setup(char *str)
315 execute_command = str;
317 * In case LILO is going to boot us with default command line,
318 * it prepends "auto" before the whole cmdline which makes
319 * the shell think it should execute a script with such name.
320 * So we ignore all arguments entered _before_ init=... [MJ]
322 for (i = 1; i < MAX_INIT_ARGS; i++)
326 __setup("init=", init_setup);
328 static int __init rdinit_setup(char *str)
332 ramdisk_execute_command = str;
333 /* See "auto" comment in init_setup */
334 for (i = 1; i < MAX_INIT_ARGS; i++)
338 __setup("rdinit=", rdinit_setup);
342 #ifdef CONFIG_X86_LOCAL_APIC
343 static void __init smp_init(void)
345 APIC_init_uniprocessor();
348 #define smp_init() do { } while (0)
351 static inline void setup_per_cpu_areas(void) { }
352 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
356 #ifdef __GENERIC_PER_CPU
357 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
359 EXPORT_SYMBOL(__per_cpu_offset);
361 static void __init setup_per_cpu_areas(void)
363 unsigned long size, vspc, i;
365 unsigned long nr_possible_cpus = num_possible_cpus();
367 /* Copy section for each CPU (we discard the original) */
368 size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
369 #ifdef CONFIG_MODULES
370 if (size < PERCPU_ENOUGH_ROOM)
371 size = PERCPU_ENOUGH_ROOM;
373 vspc = PERCPU_PERCTX * CONFIG_VSERVER_CONTEXTS;
374 size = ALIGN(size + vspc, SMP_CACHE_BYTES);
375 ptr = alloc_bootmem(size * nr_possible_cpus);
377 for_each_possible_cpu(i) {
378 __per_cpu_offset[i] = ptr - __per_cpu_start;
379 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
383 #endif /* !__GENERIC_PER_CPU */
385 #include <linux/ext3_fs_i.h>
386 #include <linux/skbuff.h>
387 #include <linux/sched.h>
389 /* Called by boot processor to activate the rest. */
390 static void __init smp_init(void)
394 /* FIXME: This should be done in userspace --RR */
395 for_each_present_cpu(i) {
396 if (num_online_cpus() >= max_cpus)
402 /* Any cleanup work */
403 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
404 smp_cpus_done(max_cpus);
406 /* Get other processors into their bootup holding patterns. */
411 printk(KERN_DEBUG "sizeof(vma)=%u bytes\n", (unsigned int) sizeof(struct vm_area_struct));
412 printk(KERN_DEBUG "sizeof(page)=%u bytes\n", (unsigned int) sizeof(struct page));
413 printk(KERN_DEBUG "sizeof(inode)=%u bytes\n", (unsigned int) sizeof(struct inode));
414 printk(KERN_DEBUG "sizeof(dentry)=%u bytes\n", (unsigned int) sizeof(struct dentry));
415 printk(KERN_DEBUG "sizeof(ext3inode)=%u bytes\n", (unsigned int) sizeof(struct ext3_inode_info));
416 printk(KERN_DEBUG "sizeof(buffer_head)=%u bytes\n", (unsigned int) sizeof(struct buffer_head));
417 printk(KERN_DEBUG "sizeof(skbuff)=%u bytes\n", (unsigned int) sizeof(struct sk_buff));
418 printk(KERN_DEBUG "sizeof(task_struct)=%u bytes\n", (unsigned int) sizeof(struct task_struct));
424 * We need to finalize in a non-__init function or else race conditions
425 * between the root thread and the init thread may cause start_kernel to
426 * be reaped by free_initmem before the root thread has proceeded to
429 * gcc-3.4 accidentally inlines this function, so use noinline.
432 static void noinline rest_init(void)
433 __releases(kernel_lock)
435 kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
436 numa_default_policy();
440 * The boot idle thread must execute schedule()
441 * at least one to get things moving:
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 if (p->setup_func(val) != 0)
460 "Malformed early option '%s'\n", param);
463 /* We accept everything at this stage. */
467 /* Arch code calls this early on, or if not, just before other parsing. */
468 void __init parse_early_param(void)
470 static __initdata int done = 0;
471 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
476 /* All fall through to do_early_param. */
477 strlcpy(tmp_cmdline, saved_command_line, COMMAND_LINE_SIZE);
478 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
483 * Activate the first processor.
486 static void __init boot_cpu_init(void)
488 int cpu = smp_processor_id();
489 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
490 cpu_set(cpu, cpu_online_map);
491 cpu_set(cpu, cpu_present_map);
492 cpu_set(cpu, cpu_possible_map);
495 void __init __attribute__((weak)) smp_setup_processor_id(void)
499 asmlinkage void __init start_kernel(void)
502 extern struct kernel_param __start___param[], __stop___param[];
504 smp_setup_processor_id();
507 * Need to run as early as possible, to initialize the
514 early_boot_irqs_off();
515 early_init_irq_lock_class();
518 * Interrupts are still disabled. Do necessary setups, then
525 printk(linux_banner);
526 setup_arch(&command_line);
528 setup_per_cpu_areas();
529 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
532 * Set up the scheduler prior starting any interrupts (such as the
533 * timer interrupt). Full topology setup happens at smp_init()
534 * time - but meanwhile we still have a functioning scheduler.
538 * Disable preemption - early bootup scheduling is extremely
539 * fragile until we cpu_idle() for the first time.
542 build_all_zonelists();
544 printk(KERN_NOTICE "Kernel command line: %s\n", saved_command_line);
546 parse_args("Booting kernel", command_line, __start___param,
547 __stop___param - __start___param,
548 &unknown_bootoption);
549 if (!irqs_disabled()) {
550 printk(KERN_WARNING "start_kernel(): bug: interrupts were "
551 "enabled *very* early, fixing it\n");
565 if (!irqs_disabled())
566 printk("start_kernel(): bug: interrupts were enabled early\n");
567 early_boot_irqs_on();
571 * HACK ALERT! This is early. We're enabling the console before
572 * we've done PCI setups etc, and console_init() must be aware of
573 * this. But we do want output early, in case something goes wrong.
577 panic(panic_later, panic_param);
582 * Need to run this when irqs are enabled, because it wants
583 * to self-test [hard/soft]-irqs on/off lock inversion bugs
588 #ifdef CONFIG_BLK_DEV_INITRD
589 if (initrd_start && !initrd_below_start_ok &&
590 initrd_start < min_low_pfn << PAGE_SHIFT) {
591 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
592 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
596 vfs_caches_init_early();
600 setup_per_cpu_pageset();
606 pgtable_cache_init();
611 efi_enter_virtual_mode();
613 fork_init(num_physpages);
619 vfs_caches_init(num_physpages);
622 /* rootfs populating might need page-writeback */
623 page_writeback_init();
624 #ifdef CONFIG_PROC_FS
628 taskstats_init_early();
633 acpi_early_init(); /* before LAPIC and SMP init */
635 /* Do the rest non-__init'ed, we're now alive */
639 static int __initdata initcall_debug;
641 static int __init initcall_debug_setup(char *str)
646 __setup("initcall_debug", initcall_debug_setup);
648 extern initcall_t __initcall_start[], __initcall_end[];
650 static void __init do_initcalls(void)
653 int count = preempt_count();
655 for (call = __initcall_start; call < __initcall_end; call++) {
660 if (initcall_debug) {
661 printk("Calling initcall 0x%p", *call);
662 print_fn_descriptor_symbol(": %s()",
663 (unsigned long) *call);
669 if (result && result != -ENODEV && initcall_debug) {
670 sprintf(msgbuf, "error code %d", result);
673 if (preempt_count() != count) {
674 msg = "preemption imbalance";
675 preempt_count() = count;
677 if (irqs_disabled()) {
678 msg = "disabled interrupts";
682 printk(KERN_WARNING "initcall at 0x%p", *call);
683 print_fn_descriptor_symbol(": %s()",
684 (unsigned long) *call);
685 printk(": returned with %s\n", msg);
689 /* Make sure there is no pending stuff from the initcall sequence */
690 flush_scheduled_work();
693 #ifdef CONFIG_BOOT_DELAY
695 unsigned int boot_delay = 0; /* msecs delay after each printk during bootup */
696 extern long preset_lpj;
697 unsigned long long printk_delay_msec = 0; /* per msec, based on boot_delay */
699 static int __init boot_delay_setup(char *str)
701 unsigned long lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */
702 unsigned long long loops_per_msec = lpj / 1000 * CONFIG_HZ;
704 get_option(&str, &boot_delay);
705 if (boot_delay > 10 * 1000)
708 printk_delay_msec = loops_per_msec;
709 printk("boot_delay: %u, preset_lpj: %ld, lpj: %lu, CONFIG_HZ: %d, printk_delay_msec: %llu\n",
710 boot_delay, preset_lpj, lpj, CONFIG_HZ, printk_delay_msec);
713 __setup("boot_delay=", boot_delay_setup);
718 * Ok, the machine is now initialized. None of the devices
719 * have been touched yet, but the CPU subsystem is up and
720 * running, and memory and process management works.
722 * Now we can finally start doing some real work..
724 static void __init do_basic_setup(void)
726 /* drivers will send hotplug events */
728 usermodehelper_init();
738 static int __initdata nosoftlockup;
740 static int __init nosoftlockup_setup(char *str)
745 __setup("nosoftlockup", nosoftlockup_setup);
747 static void __init do_pre_smp_initcalls(void)
749 extern int spawn_ksoftirqd(void);
751 extern int migration_init(void);
757 spawn_softlockup_task();
760 static void run_init_process(char *init_filename)
762 argv_init[0] = init_filename;
763 kernel_execve(init_filename, argv_init, envp_init);
766 static int init(void * unused)
770 * init can run on any cpu.
772 set_cpus_allowed(current, CPU_MASK_ALL);
774 * Tell the world that we're going to be the grim
775 * reaper of innocent orphaned children.
777 * We don't want people to have to make incorrect
778 * assumptions about where in the task array this
781 init_pid_ns.child_reaper = current;
783 cad_pid = task_pid(current);
785 smp_prepare_cpus(max_cpus);
787 do_pre_smp_initcalls();
797 * check if there is an early userspace init. If yes, let it do all
801 if (!ramdisk_execute_command)
802 ramdisk_execute_command = "/init";
804 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
805 ramdisk_execute_command = NULL;
810 * Ok, we have completed the initial bootup, and
811 * we're essentially up and running. Get rid of the
812 * initmem segments and start the user-mode stuff..
817 system_state = SYSTEM_RUNNING;
818 numa_default_policy();
820 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
821 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
826 if (ramdisk_execute_command) {
827 run_init_process(ramdisk_execute_command);
828 printk(KERN_WARNING "Failed to execute %s\n",
829 ramdisk_execute_command);
833 * We try each of these until one succeeds.
835 * The Bourne shell can be used instead of init if we are
836 * trying to recover a really broken machine.
838 if (execute_command) {
839 run_init_process(execute_command);
840 printk(KERN_WARNING "Failed to execute %s. Attempting "
841 "defaults...\n", execute_command);
843 run_init_process("/sbin/init");
844 run_init_process("/etc/init");
845 run_init_process("/bin/init");
846 run_init_process("/bin/sh");
848 panic("No init found. Try passing init= option to kernel.");