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 #define __KERNEL_SYSCALLS__
14 #include <linux/types.h>
15 #include <linux/module.h>
16 #include <linux/proc_fs.h>
17 #include <linux/kernel.h>
18 #include <linux/syscalls.h>
19 #include <linux/string.h>
20 #include <linux/ctype.h>
21 #include <linux/delay.h>
22 #include <linux/utsname.h>
23 #include <linux/ioport.h>
24 #include <linux/init.h>
25 #include <linux/smp_lock.h>
26 #include <linux/initrd.h>
27 #include <linux/hdreg.h>
28 #include <linux/bootmem.h>
29 #include <linux/tty.h>
30 #include <linux/gfp.h>
31 #include <linux/percpu.h>
32 #include <linux/kmod.h>
33 #include <linux/kernel_stat.h>
34 #include <linux/security.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/efi.h>
44 #include <linux/unistd.h>
45 #include <linux/rmap.h>
46 #include <linux/mempolicy.h>
47 #include <linux/key.h>
48 #include <linux/unwind.h>
49 #include <linux/buffer_head.h>
53 #include <asm/setup.h>
54 #include <asm/sections.h>
55 #include <asm/cacheflush.h>
57 #ifdef CONFIG_X86_LOCAL_APIC
62 * This is one of the first .c files built. Error out early if we have compiler
65 * Versions of gcc older than that listed below may actually compile and link
66 * okay, but the end product can have subtle run time bugs. To avoid associated
67 * bogus bug reports, we flatly refuse to compile with a gcc that is known to be
68 * too old from the very beginning.
70 #if (__GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 2)
71 #error Sorry, your GCC is too old. It builds incorrect kernels.
74 static int init(void *);
76 extern void init_IRQ(void);
77 extern void fork_init(unsigned long);
78 extern void mca_init(void);
79 extern void sbus_init(void);
80 extern void sysctl_init(void);
81 extern void signals_init(void);
82 extern void pidhash_init(void);
83 extern void pidmap_init(void);
84 extern void prio_tree_init(void);
85 extern void radix_tree_init(void);
86 extern void free_initmem(void);
87 extern void populate_rootfs(void);
88 extern void driver_init(void);
89 extern void prepare_namespace(void);
91 extern void acpi_early_init(void);
93 static inline void acpi_early_init(void) { }
95 #ifndef CONFIG_DEBUG_RODATA
96 static inline void mark_rodata_ro(void) { }
100 extern void tc_init(void);
103 enum system_states system_state
;
104 EXPORT_SYMBOL(system_state
);
107 * Boot command-line arguments
109 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
110 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
112 extern void time_init(void);
113 /* Default late time init is NULL. archs can override this later. */
114 void (*late_time_init
)(void);
115 extern void softirq_init(void);
117 /* Untouched command line (eg. for /proc) saved by arch-specific code. */
118 char saved_command_line
[COMMAND_LINE_SIZE
];
120 static char *execute_command
;
121 static char *ramdisk_execute_command
;
123 /* Setup configured maximum number of CPUs to activate */
124 static unsigned int max_cpus
= NR_CPUS
;
127 * Setup routine for controlling SMP activation
129 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
130 * activation entirely (the MPS table probe still happens, though).
132 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
133 * greater than 0, limits the maximum number of CPUs activated in
136 static int __init
nosmp(char *str
)
142 __setup("nosmp", nosmp
);
144 static int __init
maxcpus(char *str
)
146 get_option(&str
, &max_cpus
);
150 __setup("maxcpus=", maxcpus
);
152 static char * argv_init
[MAX_INIT_ARGS
+2] = { "init", NULL
, };
153 char * envp_init
[MAX_INIT_ENVS
+2] = { "HOME=/", "TERM=linux", NULL
, };
154 static const char *panic_later
, *panic_param
;
156 extern struct obs_kernel_param __setup_start
[], __setup_end
[];
158 static int __init
obsolete_checksetup(char *line
)
160 struct obs_kernel_param
*p
;
164 int n
= strlen(p
->str
);
165 if (!strncmp(line
, p
->str
, n
)) {
167 /* Already done in parse_early_param? (Needs
168 * exact match on param part) */
169 if (line
[n
] == '\0' || line
[n
] == '=')
171 } else if (!p
->setup_func
) {
172 printk(KERN_WARNING
"Parameter %s is obsolete,"
173 " ignored\n", p
->str
);
175 } else if (p
->setup_func(line
+ n
))
179 } while (p
< __setup_end
);
184 * This should be approx 2 Bo*oMips to start (note initial shift), and will
185 * still work even if initially too large, it will just take slightly longer
187 unsigned long loops_per_jiffy
= (1<<12);
189 EXPORT_SYMBOL(loops_per_jiffy
);
191 static int __init
debug_kernel(char *str
)
195 console_loglevel
= 10;
199 static int __init
quiet_kernel(char *str
)
203 console_loglevel
= 4;
207 __setup("debug", debug_kernel
);
208 __setup("quiet", quiet_kernel
);
210 static int __init
loglevel(char *str
)
212 get_option(&str
, &console_loglevel
);
216 __setup("loglevel=", loglevel
);
219 * Unknown boot options get handed to init, unless they look like
222 static int __init
unknown_bootoption(char *param
, char *val
)
224 /* Change NUL term back to "=", to make "param" the whole string. */
226 /* param=val or param="val"? */
227 if (val
== param
+strlen(param
)+1)
229 else if (val
== param
+strlen(param
)+2) {
231 memmove(val
-1, val
, strlen(val
)+1);
237 /* Handle obsolete-style parameters */
238 if (obsolete_checksetup(param
))
242 * Preemptive maintenance for "why didn't my mispelled command
245 if (strchr(param
, '.') && (!val
|| strchr(param
, '.') < val
)) {
246 printk(KERN_ERR
"Unknown boot option `%s': ignoring\n", param
);
254 /* Environment option */
256 for (i
= 0; envp_init
[i
]; i
++) {
257 if (i
== MAX_INIT_ENVS
) {
258 panic_later
= "Too many boot env vars at `%s'";
261 if (!strncmp(param
, envp_init
[i
], val
- param
))
264 envp_init
[i
] = param
;
266 /* Command line option */
268 for (i
= 0; argv_init
[i
]; i
++) {
269 if (i
== MAX_INIT_ARGS
) {
270 panic_later
= "Too many boot init vars at `%s'";
274 argv_init
[i
] = param
;
279 static int __init
init_setup(char *str
)
283 execute_command
= str
;
285 * In case LILO is going to boot us with default command line,
286 * it prepends "auto" before the whole cmdline which makes
287 * the shell think it should execute a script with such name.
288 * So we ignore all arguments entered _before_ init=... [MJ]
290 for (i
= 1; i
< MAX_INIT_ARGS
; i
++)
294 __setup("init=", init_setup
);
296 static int __init
rdinit_setup(char *str
)
300 ramdisk_execute_command
= str
;
301 /* See "auto" comment in init_setup */
302 for (i
= 1; i
< MAX_INIT_ARGS
; i
++)
306 __setup("rdinit=", rdinit_setup
);
310 #ifdef CONFIG_X86_LOCAL_APIC
311 static void __init
smp_init(void)
313 APIC_init_uniprocessor();
316 #define smp_init() do { } while (0)
319 static inline void setup_per_cpu_areas(void) { }
320 static inline void smp_prepare_cpus(unsigned int maxcpus
) { }
324 #ifdef __GENERIC_PER_CPU
325 unsigned long __per_cpu_offset
[NR_CPUS
] __read_mostly
;
327 EXPORT_SYMBOL(__per_cpu_offset
);
329 static void __init
setup_per_cpu_areas(void)
331 unsigned long size
, i
;
333 unsigned long nr_possible_cpus
= num_possible_cpus();
335 /* Copy section for each CPU (we discard the original) */
336 size
= ALIGN(__per_cpu_end
- __per_cpu_start
, SMP_CACHE_BYTES
);
337 #ifdef CONFIG_MODULES
338 if (size
< PERCPU_ENOUGH_ROOM
)
339 size
= PERCPU_ENOUGH_ROOM
;
341 ptr
= alloc_bootmem(size
* nr_possible_cpus
);
343 for_each_possible_cpu(i
) {
344 __per_cpu_offset
[i
] = ptr
- __per_cpu_start
;
345 memcpy(ptr
, __per_cpu_start
, __per_cpu_end
- __per_cpu_start
);
349 #endif /* !__GENERIC_PER_CPU */
351 /* Called by boot processor to activate the rest. */
352 static void __init
smp_init(void)
356 /* FIXME: This should be done in userspace --RR */
357 for_each_present_cpu(i
) {
358 if (num_online_cpus() >= max_cpus
)
364 /* Any cleanup work */
365 printk(KERN_INFO
"Brought up %ld CPUs\n", (long)num_online_cpus());
366 smp_cpus_done(max_cpus
);
368 /* Get other processors into their bootup holding patterns. */
377 * We need to finalize in a non-__init function or else race conditions
378 * between the root thread and the init thread may cause start_kernel to
379 * be reaped by free_initmem before the root thread has proceeded to
382 * gcc-3.4 accidentally inlines this function, so use noinline.
385 static void noinline
rest_init(void)
386 __releases(kernel_lock
)
388 kernel_thread(init
, NULL
, CLONE_FS
| CLONE_SIGHAND
);
389 numa_default_policy();
393 * The boot idle thread must execute schedule()
394 * at least one to get things moving:
396 preempt_enable_no_resched();
400 /* Call into cpu_idle with preempt disabled */
404 /* Check for early params. */
405 static int __init
do_early_param(char *param
, char *val
)
407 struct obs_kernel_param
*p
;
409 for (p
= __setup_start
; p
< __setup_end
; p
++) {
410 if (p
->early
&& strcmp(param
, p
->str
) == 0) {
411 if (p
->setup_func(val
) != 0)
413 "Malformed early option '%s'\n", param
);
416 /* We accept everything at this stage. */
420 /* Arch code calls this early on, or if not, just before other parsing. */
421 void __init
parse_early_param(void)
423 static __initdata
int done
= 0;
424 static __initdata
char tmp_cmdline
[COMMAND_LINE_SIZE
];
429 /* All fall through to do_early_param. */
430 strlcpy(tmp_cmdline
, saved_command_line
, COMMAND_LINE_SIZE
);
431 parse_args("early options", tmp_cmdline
, NULL
, 0, do_early_param
);
436 * Activate the first processor.
439 static void __init
boot_cpu_init(void)
441 int cpu
= smp_processor_id();
442 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
443 cpu_set(cpu
, cpu_online_map
);
444 cpu_set(cpu
, cpu_present_map
);
445 cpu_set(cpu
, cpu_possible_map
);
448 void __init
__attribute__((weak
)) smp_setup_processor_id(void)
452 asmlinkage
void __init
start_kernel(void)
455 extern struct kernel_param __start___param
[], __stop___param
[];
457 smp_setup_processor_id();
460 * Interrupts are still disabled. Do necessary setups, then
467 printk(linux_banner
);
468 setup_arch(&command_line
);
469 setup_per_cpu_areas();
470 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
473 * Set up the scheduler prior starting any interrupts (such as the
474 * timer interrupt). Full topology setup happens at smp_init()
475 * time - but meanwhile we still have a functioning scheduler.
479 * Disable preemption - early bootup scheduling is extremely
480 * fragile until we cpu_idle() for the first time.
483 build_all_zonelists();
485 printk(KERN_NOTICE
"Kernel command line: %s\n", saved_command_line
);
487 parse_args("Booting kernel", command_line
, __start___param
,
488 __stop___param
- __start___param
,
489 &unknown_bootoption
);
503 * HACK ALERT! This is early. We're enabling the console before
504 * we've done PCI setups etc, and console_init() must be aware of
505 * this. But we do want output early, in case something goes wrong.
509 panic(panic_later
, panic_param
);
512 #ifdef CONFIG_BLK_DEV_INITRD
513 if (initrd_start
&& !initrd_below_start_ok
&&
514 initrd_start
< min_low_pfn
<< PAGE_SHIFT
) {
515 printk(KERN_CRIT
"initrd overwritten (0x%08lx < 0x%08lx) - "
516 "disabling it.\n",initrd_start
,min_low_pfn
<< PAGE_SHIFT
);
520 vfs_caches_init_early();
524 setup_per_cpu_pageset();
530 pgtable_cache_init();
535 efi_enter_virtual_mode();
537 fork_init(num_physpages
);
543 vfs_caches_init(num_physpages
);
546 /* rootfs populating might need page-writeback */
547 page_writeback_init();
548 #ifdef CONFIG_PROC_FS
555 acpi_early_init(); /* before LAPIC and SMP init */
557 /* Do the rest non-__init'ed, we're now alive */
561 static int __initdata initcall_debug
;
563 static int __init
initcall_debug_setup(char *str
)
568 __setup("initcall_debug", initcall_debug_setup
);
570 struct task_struct
*child_reaper
= &init_task
;
572 extern initcall_t __initcall_start
[], __initcall_end
[];
574 static void __init
do_initcalls(void)
577 int count
= preempt_count();
579 for (call
= __initcall_start
; call
< __initcall_end
; call
++) {
584 if (initcall_debug
) {
585 printk("Calling initcall 0x%p", *call
);
586 print_fn_descriptor_symbol(": %s()",
587 (unsigned long) *call
);
593 if (result
&& result
!= -ENODEV
&& initcall_debug
) {
594 sprintf(msgbuf
, "error code %d", result
);
597 if (preempt_count() != count
) {
598 msg
= "preemption imbalance";
599 preempt_count() = count
;
601 if (irqs_disabled()) {
602 msg
= "disabled interrupts";
606 printk(KERN_WARNING
"initcall at 0x%p", *call
);
607 print_fn_descriptor_symbol(": %s()",
608 (unsigned long) *call
);
609 printk(": returned with %s\n", msg
);
613 /* Make sure there is no pending stuff from the initcall sequence */
614 flush_scheduled_work();
618 * Ok, the machine is now initialized. None of the devices
619 * have been touched yet, but the CPU subsystem is up and
620 * running, and memory and process management works.
622 * Now we can finally start doing some real work..
624 static void __init
do_basic_setup(void)
626 /* drivers will send hotplug events */
628 usermodehelper_init();
638 static void do_pre_smp_initcalls(void)
640 extern int spawn_ksoftirqd(void);
642 extern int migration_init(void);
647 spawn_softlockup_task();
650 static void run_init_process(char *init_filename
)
652 argv_init
[0] = init_filename
;
653 execve(init_filename
, argv_init
, envp_init
);
656 static int init(void * unused
)
660 * init can run on any cpu.
662 set_cpus_allowed(current
, CPU_MASK_ALL
);
664 * Tell the world that we're going to be the grim
665 * reaper of innocent orphaned children.
667 * We don't want people to have to make incorrect
668 * assumptions about where in the task array this
671 child_reaper
= current
;
673 smp_prepare_cpus(max_cpus
);
675 do_pre_smp_initcalls();
683 * Do this before initcalls, because some drivers want to access
691 * check if there is an early userspace init. If yes, let it do all
695 if (!ramdisk_execute_command
)
696 ramdisk_execute_command
= "/init";
698 if (sys_access((const char __user
*) ramdisk_execute_command
, 0) != 0) {
699 ramdisk_execute_command
= NULL
;
704 * Ok, we have completed the initial bootup, and
705 * we're essentially up and running. Get rid of the
706 * initmem segments and start the user-mode stuff..
711 system_state
= SYSTEM_RUNNING
;
712 numa_default_policy();
714 if (sys_open((const char __user
*) "/dev/console", O_RDWR
, 0) < 0)
715 printk(KERN_WARNING
"Warning: unable to open an initial console.\n");
720 if (ramdisk_execute_command
) {
721 run_init_process(ramdisk_execute_command
);
722 printk(KERN_WARNING
"Failed to execute %s\n",
723 ramdisk_execute_command
);
727 * We try each of these until one succeeds.
729 * The Bourne shell can be used instead of init if we are
730 * trying to recover a really broken machine.
732 if (execute_command
) {
733 run_init_process(execute_command
);
734 printk(KERN_WARNING
"Failed to execute %s. Attempting "
735 "defaults...\n", execute_command
);
737 run_init_process("/sbin/init");
738 run_init_process("/etc/init");
739 run_init_process("/bin/init");
740 run_init_process("/bin/sh");
742 panic("No init found. Try passing init= option to kernel.");