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/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/unwind.h>
54 #include <linux/buffer_head.h>
55 #include <linux/debug_locks.h>
56 #include <linux/debugobjects.h>
57 #include <linux/lockdep.h>
58 #include <linux/pid_namespace.h>
59 #include <linux/device.h>
60 #include <linux/kthread.h>
61 #include <linux/sched.h>
62 #include <linux/signal.h>
63 #include <linux/idr.h>
67 #include <asm/setup.h>
68 #include <asm/sections.h>
69 #include <asm/cacheflush.h>
71 #ifdef CONFIG_X86_LOCAL_APIC
76 * This is one of the first .c files built. Error out early if we have compiler
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 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 pidhash_init(void);
91 extern void pidmap_init(void);
92 extern void prio_tree_init(void);
93 extern void radix_tree_init(void);
94 extern void free_initmem(void);
96 extern void acpi_early_init(void);
98 static inline void acpi_early_init(void) { }
100 #ifndef CONFIG_DEBUG_RODATA
101 static inline void mark_rodata_ro(void) { }
105 extern void tc_init(void);
108 enum system_states system_state
;
109 EXPORT_SYMBOL(system_state
);
112 * Boot command-line arguments
114 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
115 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
117 extern void time_init(void);
118 /* Default late time init is NULL. archs can override this later. */
119 void (*late_time_init
)(void);
120 extern void softirq_init(void);
122 /* Untouched command line saved by arch-specific code. */
123 char __initdata boot_command_line
[COMMAND_LINE_SIZE
];
124 /* Untouched saved command line (eg. for /proc) */
125 char *saved_command_line
;
126 /* Command line for parameter parsing */
127 static char *static_command_line
;
129 static char *execute_command
;
130 static char *ramdisk_execute_command
;
133 /* Setup configured maximum number of CPUs to activate */
134 unsigned int __initdata setup_max_cpus
= NR_CPUS
;
137 * Setup routine for controlling SMP activation
139 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
140 * activation entirely (the MPS table probe still happens, though).
142 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
143 * greater than 0, limits the maximum number of CPUs activated in
146 #ifndef CONFIG_X86_IO_APIC
147 static inline void disable_ioapic_setup(void) {};
150 static int __init
nosmp(char *str
)
153 disable_ioapic_setup();
157 early_param("nosmp", nosmp
);
159 static int __init
maxcpus(char *str
)
161 get_option(&str
, &setup_max_cpus
);
162 if (setup_max_cpus
== 0)
163 disable_ioapic_setup();
168 early_param("maxcpus", maxcpus
);
170 #define setup_max_cpus NR_CPUS
174 * If set, this is an indication to the drivers that reset the underlying
175 * device before going ahead with the initialization otherwise driver might
176 * rely on the BIOS and skip the reset operation.
178 * This is useful if kernel is booting in an unreliable environment.
179 * For ex. kdump situaiton where previous kernel has crashed, BIOS has been
180 * skipped and devices will be in unknown state.
182 unsigned int reset_devices
;
183 EXPORT_SYMBOL(reset_devices
);
185 static int __init
set_reset_devices(char *str
)
191 __setup("reset_devices", set_reset_devices
);
193 static char * argv_init
[MAX_INIT_ARGS
+2] = { "init", NULL
, };
194 char * envp_init
[MAX_INIT_ENVS
+2] = { "HOME=/", "TERM=linux", NULL
, };
195 static const char *panic_later
, *panic_param
;
197 extern struct obs_kernel_param __setup_start
[], __setup_end
[];
199 static int __init
obsolete_checksetup(char *line
)
201 struct obs_kernel_param
*p
;
202 int had_early_param
= 0;
206 int n
= strlen(p
->str
);
207 if (!strncmp(line
, p
->str
, n
)) {
209 /* Already done in parse_early_param?
210 * (Needs exact match on param part).
211 * Keep iterating, as we can have early
212 * params and __setups of same names 8( */
213 if (line
[n
] == '\0' || line
[n
] == '=')
215 } else if (!p
->setup_func
) {
216 printk(KERN_WARNING
"Parameter %s is obsolete,"
217 " ignored\n", p
->str
);
219 } else if (p
->setup_func(line
+ n
))
223 } while (p
< __setup_end
);
225 return had_early_param
;
229 * This should be approx 2 Bo*oMips to start (note initial shift), and will
230 * still work even if initially too large, it will just take slightly longer
232 unsigned long loops_per_jiffy
= (1<<12);
234 EXPORT_SYMBOL(loops_per_jiffy
);
236 static int __init
debug_kernel(char *str
)
238 console_loglevel
= 10;
242 static int __init
quiet_kernel(char *str
)
244 console_loglevel
= 4;
248 early_param("debug", debug_kernel
);
249 early_param("quiet", quiet_kernel
);
251 static int __init
loglevel(char *str
)
253 get_option(&str
, &console_loglevel
);
257 early_param("loglevel", loglevel
);
260 * Unknown boot options get handed to init, unless they look like
263 static int __init
unknown_bootoption(char *param
, char *val
)
265 /* Change NUL term back to "=", to make "param" the whole string. */
267 /* param=val or param="val"? */
268 if (val
== param
+strlen(param
)+1)
270 else if (val
== param
+strlen(param
)+2) {
272 memmove(val
-1, val
, strlen(val
)+1);
278 /* Handle obsolete-style parameters */
279 if (obsolete_checksetup(param
))
283 * Preemptive maintenance for "why didn't my misspelled command
286 if (strchr(param
, '.') && (!val
|| strchr(param
, '.') < val
)) {
287 printk(KERN_ERR
"Unknown boot option `%s': ignoring\n", param
);
295 /* Environment option */
297 for (i
= 0; envp_init
[i
]; i
++) {
298 if (i
== MAX_INIT_ENVS
) {
299 panic_later
= "Too many boot env vars at `%s'";
302 if (!strncmp(param
, envp_init
[i
], val
- param
))
305 envp_init
[i
] = param
;
307 /* Command line option */
309 for (i
= 0; argv_init
[i
]; i
++) {
310 if (i
== MAX_INIT_ARGS
) {
311 panic_later
= "Too many boot init vars at `%s'";
315 argv_init
[i
] = param
;
320 #ifdef CONFIG_DEBUG_PAGEALLOC
321 int __read_mostly debug_pagealloc_enabled
= 0;
324 static int __init
init_setup(char *str
)
328 execute_command
= str
;
330 * In case LILO is going to boot us with default command line,
331 * it prepends "auto" before the whole cmdline which makes
332 * the shell think it should execute a script with such name.
333 * So we ignore all arguments entered _before_ init=... [MJ]
335 for (i
= 1; i
< MAX_INIT_ARGS
; i
++)
339 __setup("init=", init_setup
);
341 static int __init
rdinit_setup(char *str
)
345 ramdisk_execute_command
= str
;
346 /* See "auto" comment in init_setup */
347 for (i
= 1; i
< MAX_INIT_ARGS
; i
++)
351 __setup("rdinit=", rdinit_setup
);
355 #ifdef CONFIG_X86_LOCAL_APIC
356 static void __init
smp_init(void)
358 APIC_init_uniprocessor();
361 #define smp_init() do { } while (0)
364 static inline void setup_per_cpu_areas(void) { }
365 static inline void setup_nr_cpu_ids(void) { }
366 static inline void smp_prepare_cpus(unsigned int maxcpus
) { }
370 #if NR_CPUS > BITS_PER_LONG
371 cpumask_t cpu_mask_all __read_mostly
= CPU_MASK_ALL
;
372 EXPORT_SYMBOL(cpu_mask_all
);
375 /* Setup number of possible processor ids */
376 int nr_cpu_ids __read_mostly
= NR_CPUS
;
377 EXPORT_SYMBOL(nr_cpu_ids
);
379 /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
380 static void __init
setup_nr_cpu_ids(void)
382 int cpu
, highest_cpu
= 0;
384 for_each_possible_cpu(cpu
)
387 nr_cpu_ids
= highest_cpu
+ 1;
390 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
391 unsigned long __per_cpu_offset
[NR_CPUS
] __read_mostly
;
393 EXPORT_SYMBOL(__per_cpu_offset
);
395 static void __init
setup_per_cpu_areas(void)
397 unsigned long size
, i
;
399 unsigned long nr_possible_cpus
= num_possible_cpus();
401 /* Copy section for each CPU (we discard the original) */
402 size
= ALIGN(PERCPU_ENOUGH_ROOM
, PAGE_SIZE
);
403 ptr
= alloc_bootmem_pages(size
* nr_possible_cpus
);
405 for_each_possible_cpu(i
) {
406 __per_cpu_offset
[i
] = ptr
- __per_cpu_start
;
407 memcpy(ptr
, __per_cpu_start
, __per_cpu_end
- __per_cpu_start
);
411 #endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
413 /* Called by boot processor to activate the rest. */
414 static void __init
smp_init(void)
418 /* FIXME: This should be done in userspace --RR */
419 for_each_present_cpu(cpu
) {
420 if (num_online_cpus() >= setup_max_cpus
)
422 if (!cpu_online(cpu
))
426 /* Any cleanup work */
427 printk(KERN_INFO
"Brought up %ld CPUs\n", (long)num_online_cpus());
428 smp_cpus_done(setup_max_cpus
);
434 * We need to store the untouched command line for future reference.
435 * We also need to store the touched command line since the parameter
436 * parsing is performed in place, and we should allow a component to
437 * store reference of name/value for future reference.
439 static void __init
setup_command_line(char *command_line
)
441 saved_command_line
= alloc_bootmem(strlen (boot_command_line
)+1);
442 static_command_line
= alloc_bootmem(strlen (command_line
)+1);
443 strcpy (saved_command_line
, boot_command_line
);
444 strcpy (static_command_line
, command_line
);
448 * We need to finalize in a non-__init function or else race conditions
449 * between the root thread and the init thread may cause start_kernel to
450 * be reaped by free_initmem before the root thread has proceeded to
453 * gcc-3.4 accidentally inlines this function, so use noinline.
456 static void noinline __init_refok
rest_init(void)
457 __releases(kernel_lock
)
461 kernel_thread(kernel_init
, NULL
, CLONE_FS
| CLONE_SIGHAND
);
462 numa_default_policy();
463 pid
= kernel_thread(kthreadd
, NULL
, CLONE_FS
| CLONE_FILES
);
464 kthreadd_task
= find_task_by_pid_ns(pid
, &init_pid_ns
);
468 * The boot idle thread must execute schedule()
469 * at least once to get things moving:
471 init_idle_bootup_task(current
);
472 preempt_enable_no_resched();
476 /* Call into cpu_idle with preempt disabled */
480 /* Check for early params. */
481 static int __init
do_early_param(char *param
, char *val
)
483 struct obs_kernel_param
*p
;
485 for (p
= __setup_start
; p
< __setup_end
; p
++) {
486 if ((p
->early
&& strcmp(param
, p
->str
) == 0) ||
487 (strcmp(param
, "console") == 0 &&
488 strcmp(p
->str
, "earlycon") == 0)
490 if (p
->setup_func(val
) != 0)
492 "Malformed early option '%s'\n", param
);
495 /* We accept everything at this stage. */
499 /* Arch code calls this early on, or if not, just before other parsing. */
500 void __init
parse_early_param(void)
502 static __initdata
int done
= 0;
503 static __initdata
char tmp_cmdline
[COMMAND_LINE_SIZE
];
508 /* All fall through to do_early_param. */
509 strlcpy(tmp_cmdline
, boot_command_line
, COMMAND_LINE_SIZE
);
510 parse_args("early options", tmp_cmdline
, NULL
, 0, do_early_param
);
515 * Activate the first processor.
518 static void __init
boot_cpu_init(void)
520 int cpu
= smp_processor_id();
521 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
522 cpu_set(cpu
, cpu_online_map
);
523 cpu_set(cpu
, cpu_present_map
);
524 cpu_set(cpu
, cpu_possible_map
);
527 void __init __weak
smp_setup_processor_id(void)
531 void __init __weak
thread_info_cache_init(void)
535 asmlinkage
void __init
start_kernel(void)
538 extern struct kernel_param __start___param
[], __stop___param
[];
540 smp_setup_processor_id();
543 * Need to run as early as possible, to initialize the
548 debug_objects_early_init();
552 early_boot_irqs_off();
553 early_init_irq_lock_class();
556 * Interrupts are still disabled. Do necessary setups, then
564 printk(linux_banner
);
565 setup_arch(&command_line
);
566 mm_init_owner(&init_mm
, &init_task
);
567 setup_command_line(command_line
);
569 setup_per_cpu_areas();
571 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
574 * Set up the scheduler prior starting any interrupts (such as the
575 * timer interrupt). Full topology setup happens at smp_init()
576 * time - but meanwhile we still have a functioning scheduler.
580 * Disable preemption - early bootup scheduling is extremely
581 * fragile until we cpu_idle() for the first time.
584 build_all_zonelists();
586 printk(KERN_NOTICE
"Kernel command line: %s\n", boot_command_line
);
588 parse_args("Booting kernel", static_command_line
, __start___param
,
589 __stop___param
- __start___param
,
590 &unknown_bootoption
);
591 if (!irqs_disabled()) {
592 printk(KERN_WARNING
"start_kernel(): bug: interrupts were "
593 "enabled *very* early, fixing it\n");
608 if (!irqs_disabled())
609 printk("start_kernel(): bug: interrupts were enabled early\n");
610 early_boot_irqs_on();
614 * HACK ALERT! This is early. We're enabling the console before
615 * we've done PCI setups etc, and console_init() must be aware of
616 * this. But we do want output early, in case something goes wrong.
620 panic(panic_later
, panic_param
);
625 * Need to run this when irqs are enabled, because it wants
626 * to self-test [hard/soft]-irqs on/off lock inversion bugs
631 #ifdef CONFIG_BLK_DEV_INITRD
632 if (initrd_start
&& !initrd_below_start_ok
&&
633 initrd_start
< min_low_pfn
<< PAGE_SHIFT
) {
634 printk(KERN_CRIT
"initrd overwritten (0x%08lx < 0x%08lx) - "
635 "disabling it.\n",initrd_start
,min_low_pfn
<< PAGE_SHIFT
);
639 vfs_caches_init_early();
642 enable_debug_pagealloc();
645 debug_objects_mem_init();
647 setup_per_cpu_pageset();
653 pgtable_cache_init();
658 efi_enter_virtual_mode();
660 thread_info_cache_init();
661 fork_init(num_physpages
);
667 vfs_caches_init(num_physpages
);
670 /* rootfs populating might need page-writeback */
671 page_writeback_init();
672 #ifdef CONFIG_PROC_FS
677 taskstats_init_early();
682 acpi_early_init(); /* before LAPIC and SMP init */
684 /* Do the rest non-__init'ed, we're now alive */
688 static int __initdata initcall_debug
;
690 static int __init
initcall_debug_setup(char *str
)
695 __setup("initcall_debug", initcall_debug_setup
);
697 static void __init
do_one_initcall(initcall_t fn
)
699 int count
= preempt_count();
700 ktime_t t0
, t1
, delta
;
704 if (initcall_debug
) {
705 print_fn_descriptor_symbol("calling %s\n", fn
);
711 if (initcall_debug
) {
713 delta
= ktime_sub(t1
, t0
);
715 print_fn_descriptor_symbol("initcall %s", fn
);
716 printk(" returned %d after %Ld msecs\n", result
,
717 (unsigned long long) delta
.tv64
>> 20);
722 if (result
&& result
!= -ENODEV
&& initcall_debug
)
723 sprintf(msgbuf
, "error code %d ", result
);
725 if (preempt_count() != count
) {
726 strlcat(msgbuf
, "preemption imbalance ", sizeof(msgbuf
));
727 preempt_count() = count
;
729 if (irqs_disabled()) {
730 strlcat(msgbuf
, "disabled interrupts ", sizeof(msgbuf
));
734 print_fn_descriptor_symbol(KERN_WARNING
"initcall %s", fn
);
735 printk(" returned with %s\n", msgbuf
);
740 extern initcall_t __initcall_start
[], __initcall_end
[];
742 static void __init
do_initcalls(void)
746 for (call
= __initcall_start
; call
< __initcall_end
; call
++)
747 do_one_initcall(*call
);
749 /* Make sure there is no pending stuff from the initcall sequence */
750 flush_scheduled_work();
754 * Ok, the machine is now initialized. None of the devices
755 * have been touched yet, but the CPU subsystem is up and
756 * running, and memory and process management works.
758 * Now we can finally start doing some real work..
760 static void __init
do_basic_setup(void)
762 rcu_init_sched(); /* needed by module_init stage. */
763 /* drivers will send hotplug events */
765 usermodehelper_init();
771 static int __initdata nosoftlockup
;
773 static int __init
nosoftlockup_setup(char *str
)
778 __setup("nosoftlockup", nosoftlockup_setup
);
780 static void __init
do_pre_smp_initcalls(void)
782 extern int spawn_ksoftirqd(void);
784 init_call_single_data();
788 spawn_softlockup_task();
791 static void run_init_process(char *init_filename
)
793 argv_init
[0] = init_filename
;
794 kernel_execve(init_filename
, argv_init
, envp_init
);
797 /* This is a non __init function. Force it to be noinline otherwise gcc
798 * makes it inline to init() and it becomes part of init.text section
800 static int noinline
init_post(void)
805 system_state
= SYSTEM_RUNNING
;
806 numa_default_policy();
808 if (sys_open((const char __user
*) "/dev/console", O_RDWR
, 0) < 0)
809 printk(KERN_WARNING
"Warning: unable to open an initial console.\n");
814 current
->signal
->flags
|= SIGNAL_UNKILLABLE
;
816 if (ramdisk_execute_command
) {
817 run_init_process(ramdisk_execute_command
);
818 printk(KERN_WARNING
"Failed to execute %s\n",
819 ramdisk_execute_command
);
823 * We try each of these until one succeeds.
825 * The Bourne shell can be used instead of init if we are
826 * trying to recover a really broken machine.
828 if (execute_command
) {
829 run_init_process(execute_command
);
830 printk(KERN_WARNING
"Failed to execute %s. Attempting "
831 "defaults...\n", execute_command
);
833 run_init_process("/sbin/init");
834 run_init_process("/etc/init");
835 run_init_process("/bin/init");
836 run_init_process("/bin/sh");
838 panic("No init found. Try passing init= option to kernel.");
841 static int __init
kernel_init(void * unused
)
845 * init can run on any cpu.
847 set_cpus_allowed_ptr(current
, CPU_MASK_ALL_PTR
);
849 * Tell the world that we're going to be the grim
850 * reaper of innocent orphaned children.
852 * We don't want people to have to make incorrect
853 * assumptions about where in the task array this
856 init_pid_ns
.child_reaper
= current
;
858 cad_pid
= task_pid(current
);
860 smp_prepare_cpus(setup_max_cpus
);
862 do_pre_smp_initcalls();
872 * check if there is an early userspace init. If yes, let it do all
876 if (!ramdisk_execute_command
)
877 ramdisk_execute_command
= "/init";
879 if (sys_access((const char __user
*) ramdisk_execute_command
, 0) != 0) {
880 ramdisk_execute_command
= NULL
;
885 * Ok, we have completed the initial bootup, and
886 * we're essentially up and running. Get rid of the
887 * initmem segments and start the user-mode stuff..