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/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>
75 #include <asm/setup.h>
76 #include <asm/sections.h>
77 #include <asm/cacheflush.h>
79 #ifdef CONFIG_X86_LOCAL_APIC
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 prio_tree_init(void);
90 extern void radix_tree_init(void);
91 extern void free_initmem(void);
92 #ifndef CONFIG_DEBUG_RODATA
93 static inline void mark_rodata_ro(void) { }
97 extern void tc_init(void);
100 enum system_states system_state __read_mostly
;
101 EXPORT_SYMBOL(system_state
);
104 * Boot command-line arguments
106 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
107 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
109 extern void time_init(void);
110 /* Default late time init is NULL. archs can override this later. */
111 void (*__initdata late_time_init
)(void);
112 extern void softirq_init(void);
114 /* Untouched command line saved by arch-specific code. */
115 char __initdata boot_command_line
[COMMAND_LINE_SIZE
];
116 /* Untouched saved command line (eg. for /proc) */
117 char *saved_command_line
;
118 /* Command line for parameter parsing */
119 static char *static_command_line
;
121 static char *execute_command
;
122 static char *ramdisk_execute_command
;
125 /* Setup configured maximum number of CPUs to activate */
126 unsigned int setup_max_cpus
= NR_CPUS
;
127 EXPORT_SYMBOL(setup_max_cpus
);
131 * Setup routine for controlling SMP activation
133 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
134 * activation entirely (the MPS table probe still happens, though).
136 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
137 * greater than 0, limits the maximum number of CPUs activated in
141 void __weak
arch_disable_smp_support(void) { }
143 static int __init
nosmp(char *str
)
146 arch_disable_smp_support();
151 early_param("nosmp", nosmp
);
153 /* this is hard limit */
154 static int __init
nrcpus(char *str
)
158 get_option(&str
, &nr_cpus
);
159 if (nr_cpus
> 0 && nr_cpus
< nr_cpu_ids
)
160 nr_cpu_ids
= nr_cpus
;
165 early_param("nr_cpus", nrcpus
);
167 static int __init
maxcpus(char *str
)
169 get_option(&str
, &setup_max_cpus
);
170 if (setup_max_cpus
== 0)
171 arch_disable_smp_support();
176 early_param("maxcpus", maxcpus
);
178 static const unsigned int setup_max_cpus
= NR_CPUS
;
182 * If set, this is an indication to the drivers that reset the underlying
183 * device before going ahead with the initialization otherwise driver might
184 * rely on the BIOS and skip the reset operation.
186 * This is useful if kernel is booting in an unreliable environment.
187 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
188 * skipped and devices will be in unknown state.
190 unsigned int reset_devices
;
191 EXPORT_SYMBOL(reset_devices
);
193 static int __init
set_reset_devices(char *str
)
199 __setup("reset_devices", set_reset_devices
);
201 static char * argv_init
[MAX_INIT_ARGS
+2] = { "init", NULL
, };
202 char * envp_init
[MAX_INIT_ENVS
+2] = { "HOME=/", "TERM=linux", NULL
, };
203 static const char *panic_later
, *panic_param
;
205 extern struct obs_kernel_param __setup_start
[], __setup_end
[];
207 static int __init
obsolete_checksetup(char *line
)
209 struct obs_kernel_param
*p
;
210 int had_early_param
= 0;
214 int n
= strlen(p
->str
);
215 if (!strncmp(line
, p
->str
, n
)) {
217 /* Already done in parse_early_param?
218 * (Needs exact match on param part).
219 * Keep iterating, as we can have early
220 * params and __setups of same names 8( */
221 if (line
[n
] == '\0' || line
[n
] == '=')
223 } else if (!p
->setup_func
) {
224 printk(KERN_WARNING
"Parameter %s is obsolete,"
225 " ignored\n", p
->str
);
227 } else if (p
->setup_func(line
+ n
))
231 } while (p
< __setup_end
);
233 return had_early_param
;
237 * This should be approx 2 Bo*oMips to start (note initial shift), and will
238 * still work even if initially too large, it will just take slightly longer
240 unsigned long loops_per_jiffy
= (1<<12);
242 EXPORT_SYMBOL(loops_per_jiffy
);
244 static int __init
debug_kernel(char *str
)
246 console_loglevel
= 10;
250 static int __init
quiet_kernel(char *str
)
252 console_loglevel
= 4;
256 early_param("debug", debug_kernel
);
257 early_param("quiet", quiet_kernel
);
259 static int __init
loglevel(char *str
)
261 get_option(&str
, &console_loglevel
);
265 early_param("loglevel", loglevel
);
268 * Unknown boot options get handed to init, unless they look like
269 * unused parameters (modprobe will find them in /proc/cmdline).
271 static int __init
unknown_bootoption(char *param
, char *val
)
273 /* Change NUL term back to "=", to make "param" the whole string. */
275 /* param=val or param="val"? */
276 if (val
== param
+strlen(param
)+1)
278 else if (val
== param
+strlen(param
)+2) {
280 memmove(val
-1, val
, strlen(val
)+1);
286 /* Handle obsolete-style parameters */
287 if (obsolete_checksetup(param
))
290 /* Unused module parameter. */
291 if (strchr(param
, '.') && (!val
|| strchr(param
, '.') < val
))
298 /* Environment option */
300 for (i
= 0; envp_init
[i
]; i
++) {
301 if (i
== MAX_INIT_ENVS
) {
302 panic_later
= "Too many boot env vars at `%s'";
305 if (!strncmp(param
, envp_init
[i
], val
- param
))
308 envp_init
[i
] = param
;
310 /* Command line option */
312 for (i
= 0; argv_init
[i
]; i
++) {
313 if (i
== MAX_INIT_ARGS
) {
314 panic_later
= "Too many boot init vars at `%s'";
318 argv_init
[i
] = param
;
323 #ifdef CONFIG_DEBUG_PAGEALLOC
324 int __read_mostly debug_pagealloc_enabled
= 0;
327 static int __init
init_setup(char *str
)
331 execute_command
= str
;
333 * In case LILO is going to boot us with default command line,
334 * it prepends "auto" before the whole cmdline which makes
335 * the shell think it should execute a script with such name.
336 * So we ignore all arguments entered _before_ init=... [MJ]
338 for (i
= 1; i
< MAX_INIT_ARGS
; i
++)
342 __setup("init=", init_setup
);
344 static int __init
rdinit_setup(char *str
)
348 ramdisk_execute_command
= str
;
349 /* See "auto" comment in init_setup */
350 for (i
= 1; i
< MAX_INIT_ARGS
; i
++)
354 __setup("rdinit=", rdinit_setup
);
358 #ifdef CONFIG_X86_LOCAL_APIC
359 static void __init
smp_init(void)
361 APIC_init_uniprocessor();
364 #define smp_init() do { } while (0)
367 static inline void setup_nr_cpu_ids(void) { }
368 static inline void smp_prepare_cpus(unsigned int maxcpus
) { }
372 /* Setup number of possible processor ids */
373 int nr_cpu_ids __read_mostly
= NR_CPUS
;
374 EXPORT_SYMBOL(nr_cpu_ids
);
376 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
377 static void __init
setup_nr_cpu_ids(void)
379 nr_cpu_ids
= find_last_bit(cpumask_bits(cpu_possible_mask
),NR_CPUS
) + 1;
382 /* Called by boot processor to activate the rest. */
383 static void __init
smp_init(void)
387 /* FIXME: This should be done in userspace --RR */
388 for_each_present_cpu(cpu
) {
389 if (num_online_cpus() >= setup_max_cpus
)
391 if (!cpu_online(cpu
))
395 /* Any cleanup work */
396 printk(KERN_INFO
"Brought up %ld CPUs\n", (long)num_online_cpus());
397 smp_cpus_done(setup_max_cpus
);
403 * We need to store the untouched command line for future reference.
404 * We also need to store the touched command line since the parameter
405 * parsing is performed in place, and we should allow a component to
406 * store reference of name/value for future reference.
408 static void __init
setup_command_line(char *command_line
)
410 saved_command_line
= alloc_bootmem(strlen (boot_command_line
)+1);
411 static_command_line
= alloc_bootmem(strlen (command_line
)+1);
412 strcpy (saved_command_line
, boot_command_line
);
413 strcpy (static_command_line
, command_line
);
417 * We need to finalize in a non-__init function or else race conditions
418 * between the root thread and the init thread may cause start_kernel to
419 * be reaped by free_initmem before the root thread has proceeded to
422 * gcc-3.4 accidentally inlines this function, so use noinline.
425 static __initdata
DECLARE_COMPLETION(kthreadd_done
);
427 static noinline
void __init_refok
rest_init(void)
428 __releases(kernel_lock
)
432 rcu_scheduler_starting();
434 * We need to spawn init first so that it obtains pid 1, however
435 * the init task will end up wanting to create kthreads, which, if
436 * we schedule it before we create kthreadd, will OOPS.
438 kernel_thread(kernel_init
, NULL
, CLONE_FS
| CLONE_SIGHAND
);
439 numa_default_policy();
440 pid
= kernel_thread(kthreadd
, NULL
, CLONE_FS
| CLONE_FILES
);
442 kthreadd_task
= find_task_by_pid_ns(pid
, &init_pid_ns
);
444 complete(&kthreadd_done
);
448 * The boot idle thread must execute schedule()
449 * at least once to get things moving:
451 init_idle_bootup_task(current
);
452 preempt_enable_no_resched();
456 /* Call into cpu_idle with preempt disabled */
460 /* Check for early params. */
461 static int __init
do_early_param(char *param
, char *val
)
463 struct obs_kernel_param
*p
;
465 for (p
= __setup_start
; p
< __setup_end
; p
++) {
466 if ((p
->early
&& strcmp(param
, p
->str
) == 0) ||
467 (strcmp(param
, "console") == 0 &&
468 strcmp(p
->str
, "earlycon") == 0)
470 if (p
->setup_func(val
) != 0)
472 "Malformed early option '%s'\n", param
);
475 /* We accept everything at this stage. */
479 void __init
parse_early_options(char *cmdline
)
481 parse_args("early options", cmdline
, NULL
, 0, do_early_param
);
484 /* Arch code calls this early on, or if not, just before other parsing. */
485 void __init
parse_early_param(void)
487 static __initdata
int done
= 0;
488 static __initdata
char tmp_cmdline
[COMMAND_LINE_SIZE
];
493 /* All fall through to do_early_param. */
494 strlcpy(tmp_cmdline
, boot_command_line
, COMMAND_LINE_SIZE
);
495 parse_early_options(tmp_cmdline
);
500 * Activate the first processor.
503 static void __init
boot_cpu_init(void)
505 int cpu
= smp_processor_id();
506 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
507 set_cpu_online(cpu
, true);
508 set_cpu_active(cpu
, true);
509 set_cpu_present(cpu
, true);
510 set_cpu_possible(cpu
, true);
513 void __init __weak
smp_setup_processor_id(void)
517 void __init __weak
thread_info_cache_init(void)
522 * Set up kernel memory allocators
524 static void __init
mm_init(void)
527 * page_cgroup requires countinous pages as memmap
528 * and it's bigger than MAX_ORDER unless SPARSEMEM.
530 page_cgroup_init_flatmem();
534 pgtable_cache_init();
538 asmlinkage
void __init
start_kernel(void)
541 extern struct kernel_param __start___param
[], __stop___param
[];
543 smp_setup_processor_id();
546 * Need to run as early as possible, to initialize the
550 debug_objects_early_init();
553 * Set up the the initial canary ASAP:
555 boot_init_stack_canary();
560 early_boot_irqs_off();
561 early_init_irq_lock_class();
564 * Interrupts are still disabled. Do necessary setups, then
571 printk(KERN_NOTICE
"%s", linux_banner
);
572 setup_arch(&command_line
);
573 mm_init_owner(&init_mm
, &init_task
);
574 setup_command_line(command_line
);
576 setup_per_cpu_areas();
577 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
579 build_all_zonelists(NULL
);
582 printk(KERN_NOTICE
"Kernel command line: %s\n", boot_command_line
);
584 parse_args("Booting kernel", static_command_line
, __start___param
,
585 __stop___param
- __start___param
,
586 &unknown_bootoption
);
588 * These use large bootmem allocations and must precede
592 vfs_caches_init_early();
597 * Set up the scheduler prior starting any interrupts (such as the
598 * timer interrupt). Full topology setup happens at smp_init()
599 * time - but meanwhile we still have a functioning scheduler.
603 * Disable preemption - early bootup scheduling is extremely
604 * fragile until we cpu_idle() for the first time.
607 if (!irqs_disabled()) {
608 printk(KERN_WARNING
"start_kernel(): bug: interrupts were "
609 "enabled *very* early, fixing it\n");
614 /* init some links before init_ISA_irqs() */
624 if (!irqs_disabled())
625 printk(KERN_CRIT
"start_kernel(): bug: interrupts were "
627 early_boot_irqs_on();
630 /* Interrupts are enabled now so all GFP allocations are safe. */
631 gfp_allowed_mask
= __GFP_BITS_MASK
;
633 kmem_cache_init_late();
636 * HACK ALERT! This is early. We're enabling the console before
637 * we've done PCI setups etc, and console_init() must be aware of
638 * this. But we do want output early, in case something goes wrong.
642 panic(panic_later
, panic_param
);
647 * Need to run this when irqs are enabled, because it wants
648 * to self-test [hard/soft]-irqs on/off lock inversion bugs
653 #ifdef CONFIG_BLK_DEV_INITRD
654 if (initrd_start
&& !initrd_below_start_ok
&&
655 page_to_pfn(virt_to_page((void *)initrd_start
)) < min_low_pfn
) {
656 printk(KERN_CRIT
"initrd overwritten (0x%08lx < 0x%08lx) - "
658 page_to_pfn(virt_to_page((void *)initrd_start
)),
664 enable_debug_pagealloc();
666 debug_objects_mem_init();
668 setup_per_cpu_pageset();
678 efi_enter_virtual_mode();
680 thread_info_cache_init();
682 fork_init(totalram_pages
);
688 vfs_caches_init(totalram_pages
);
690 /* rootfs populating might need page-writeback */
691 page_writeback_init();
692 #ifdef CONFIG_PROC_FS
697 taskstats_init_early();
702 acpi_early_init(); /* before LAPIC and SMP init */
707 /* Do the rest non-__init'ed, we're now alive */
711 /* Call all constructor functions linked into the kernel. */
712 static void __init
do_ctors(void)
714 #ifdef CONFIG_CONSTRUCTORS
715 ctor_fn_t
*fn
= (ctor_fn_t
*) __ctors_start
;
717 for (; fn
< (ctor_fn_t
*) __ctors_end
; fn
++)
723 core_param(initcall_debug
, initcall_debug
, bool, 0644);
725 static char msgbuf
[64];
727 int do_one_initcall(initcall_t fn
)
729 int count
= preempt_count();
730 ktime_t calltime
, delta
, rettime
;
731 unsigned long long duration
;
734 if (initcall_debug
) {
735 printk("calling %pF @ %i\n", fn
, task_pid_nr(current
));
736 calltime
= ktime_get();
741 if (initcall_debug
) {
742 rettime
= ktime_get();
743 delta
= ktime_sub(rettime
, calltime
);
744 duration
= (unsigned long long) ktime_to_ns(delta
) >> 10;
745 printk("initcall %pF returned %d after %lld usecs\n", fn
,
751 if (ret
&& ret
!= -ENODEV
&& initcall_debug
)
752 sprintf(msgbuf
, "error code %d ", ret
);
754 if (preempt_count() != count
) {
755 strlcat(msgbuf
, "preemption imbalance ", sizeof(msgbuf
));
756 preempt_count() = count
;
758 if (irqs_disabled()) {
759 strlcat(msgbuf
, "disabled interrupts ", sizeof(msgbuf
));
763 printk("initcall %pF returned with %s\n", fn
, msgbuf
);
770 extern initcall_t __initcall_start
[], __initcall_end
[], __early_initcall_end
[];
772 static void __init
do_initcalls(void)
776 for (fn
= __early_initcall_end
; fn
< __initcall_end
; fn
++)
777 do_one_initcall(*fn
);
779 /* Make sure there is no pending stuff from the initcall sequence */
780 flush_scheduled_work();
784 * Ok, the machine is now initialized. None of the devices
785 * have been touched yet, but the CPU subsystem is up and
786 * running, and memory and process management works.
788 * Now we can finally start doing some real work..
790 static void __init
do_basic_setup(void)
794 usermodehelper_init();
802 static void __init
do_pre_smp_initcalls(void)
806 for (fn
= __initcall_start
; fn
< __early_initcall_end
; fn
++)
807 do_one_initcall(*fn
);
810 static void run_init_process(char *init_filename
)
812 argv_init
[0] = init_filename
;
813 kernel_execve(init_filename
, argv_init
, envp_init
);
816 /* This is a non __init function. Force it to be noinline otherwise gcc
817 * makes it inline to init() and it becomes part of init.text section
819 static noinline
int init_post(void)
820 __releases(kernel_lock
)
822 /* need to finish all async __init code before freeing the memory */
823 async_synchronize_full();
827 system_state
= SYSTEM_RUNNING
;
828 numa_default_policy();
831 current
->signal
->flags
|= SIGNAL_UNKILLABLE
;
833 if (ramdisk_execute_command
) {
834 run_init_process(ramdisk_execute_command
);
835 printk(KERN_WARNING
"Failed to execute %s\n",
836 ramdisk_execute_command
);
840 * We try each of these until one succeeds.
842 * The Bourne shell can be used instead of init if we are
843 * trying to recover a really broken machine.
845 if (execute_command
) {
846 run_init_process(execute_command
);
847 printk(KERN_WARNING
"Failed to execute %s. Attempting "
848 "defaults...\n", execute_command
);
850 run_init_process("/sbin/init");
851 run_init_process("/etc/init");
852 run_init_process("/bin/init");
853 run_init_process("/bin/sh");
855 panic("No init found. Try passing init= option to kernel. "
856 "See Linux Documentation/init.txt for guidance.");
859 static int __init
kernel_init(void * unused
)
862 * Wait until kthreadd is all set-up.
864 wait_for_completion(&kthreadd_done
);
868 * init can allocate pages on any node
870 set_mems_allowed(node_states
[N_HIGH_MEMORY
]);
872 * init can run on any cpu.
874 set_cpus_allowed_ptr(current
, cpu_all_mask
);
876 * Tell the world that we're going to be the grim
877 * reaper of innocent orphaned children.
879 * We don't want people to have to make incorrect
880 * assumptions about where in the task array this
883 init_pid_ns
.child_reaper
= current
;
885 cad_pid
= task_pid(current
);
887 smp_prepare_cpus(setup_max_cpus
);
889 do_pre_smp_initcalls();
896 /* Open the /dev/console on the rootfs, this should never fail */
897 if (sys_open((const char __user
*) "/dev/console", O_RDWR
, 0) < 0)
898 printk(KERN_WARNING
"Warning: unable to open an initial console.\n");
903 * check if there is an early userspace init. If yes, let it do all
907 if (!ramdisk_execute_command
)
908 ramdisk_execute_command
= "/init";
910 if (sys_access((const char __user
*) ramdisk_execute_command
, 0) != 0) {
911 ramdisk_execute_command
= NULL
;
916 * Ok, we have completed the initial bootup, and
917 * we're essentially up and running. Get rid of the
918 * initmem segments and start the user-mode stuff..