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/config.h>
15 #include <linux/proc_fs.h>
16 #include <linux/devfs_fs_kernel.h>
17 #include <linux/kernel.h>
18 #include <linux/unistd.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/kernel_stat.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/writeback.h>
39 #include <linux/cpu.h>
45 * This is one of the first .c files built. Error out early
46 * if we have compiler trouble..
48 #if __GNUC__ == 2 && __GNUC_MINOR__ == 96
49 #ifdef CONFIG_FRAME_POINTER
50 #error This compiler cannot compile correctly with frame pointers enabled
54 #ifdef CONFIG_X86_LOCAL_APIC
59 * Versions of gcc older than that listed below may actually compile
60 * and link okay, but the end product can have subtle run time bugs.
61 * To avoid associated bogus bug reports, we flatly refuse to compile
62 * with a gcc that is known to be too old from the very beginning.
64 #if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 95)
65 #error Sorry, your GCC is too old. It builds incorrect kernels.
68 extern char *linux_banner
;
70 static int init(void *);
72 extern void init_IRQ(void);
73 extern void sock_init(void);
74 extern void fork_init(unsigned long);
75 extern void mca_init(void);
76 extern void sbus_init(void);
77 extern void sysctl_init(void);
78 extern void signals_init(void);
79 extern void buffer_init(void);
80 extern void pidhash_init(void);
81 extern void pidmap_init(void);
82 extern void pte_chain_init(void);
83 extern void radix_tree_init(void);
84 extern void free_initmem(void);
85 extern void populate_rootfs(void);
86 extern void driver_init(void);
89 extern void tc_init(void);
93 * Are we up and running (ie do we have all the infrastructure
96 int system_running
= 0;
99 * Boot command-line arguments
101 #define MAX_INIT_ARGS 8
102 #define MAX_INIT_ENVS 8
104 extern void time_init(void);
105 /* Default late time init is NULL. archs can override this later. */
106 void (*late_time_init
)(void) = NULL
;
107 extern void softirq_init(void);
111 char *execute_command
;
113 /* Setup configured maximum number of CPUs to activate */
114 static unsigned int max_cpus
= NR_CPUS
;
117 * Setup routine for controlling SMP activation
119 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
120 * activation entirely (the MPS table probe still happens, though).
122 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
123 * greater than 0, limits the maximum number of CPUs activated in
126 static int __init
nosmp(char *str
)
132 __setup("nosmp", nosmp
);
134 static int __init
maxcpus(char *str
)
136 get_option(&str
, &max_cpus
);
140 __setup("maxcpus=", maxcpus
);
142 static char * argv_init
[MAX_INIT_ARGS
+2] = { "init", NULL
, };
143 char * envp_init
[MAX_INIT_ENVS
+2] = { "HOME=/", "TERM=linux", NULL
, };
145 __setup("profile=", profile_setup
);
147 static int __init
obsolete_checksetup(char *line
)
149 struct obs_kernel_param
*p
;
150 extern struct obs_kernel_param __setup_start
, __setup_end
;
154 int n
= strlen(p
->str
);
155 if (!strncmp(line
,p
->str
,n
)) {
156 if (p
->setup_func(line
+n
))
160 } while (p
< &__setup_end
);
164 /* this should be approx 2 Bo*oMips to start (note initial shift), and will
165 still work even if initially too large, it will just take slightly longer */
166 unsigned long loops_per_jiffy
= (1<<12);
168 /* This is the number of bits of precision for the loops_per_jiffy. Each
169 bit takes on average 1.5/HZ seconds. This (like the original) is a little
173 void __init
calibrate_delay(void)
175 unsigned long ticks
, loopbit
;
176 int lps_precision
= LPS_PREC
;
178 loops_per_jiffy
= (1<<12);
180 printk("Calibrating delay loop... ");
181 while (loops_per_jiffy
<<= 1) {
182 /* wait for "start of" clock tick */
184 while (ticks
== jiffies
)
188 __delay(loops_per_jiffy
);
189 ticks
= jiffies
- ticks
;
194 /* Do a binary approximation to get loops_per_jiffy set to equal one clock
195 (up to lps_precision bits) */
196 loops_per_jiffy
>>= 1;
197 loopbit
= loops_per_jiffy
;
198 while ( lps_precision
-- && (loopbit
>>= 1) ) {
199 loops_per_jiffy
|= loopbit
;
201 while (ticks
== jiffies
);
203 __delay(loops_per_jiffy
);
204 if (jiffies
!= ticks
) /* longer than 1 tick */
205 loops_per_jiffy
&= ~loopbit
;
208 /* Round the value and print it */
209 printk("%lu.%02lu BogoMIPS\n",
210 loops_per_jiffy
/(500000/HZ
),
211 (loops_per_jiffy
/(5000/HZ
)) % 100);
214 static int __init
debug_kernel(char *str
)
218 console_loglevel
= 10;
222 static int __init
quiet_kernel(char *str
)
226 console_loglevel
= 4;
230 __setup("debug", debug_kernel
);
231 __setup("quiet", quiet_kernel
);
233 /* Unknown boot options get handed to init, unless they look like
235 static int __init
unknown_bootoption(char *param
, char *val
)
237 /* Change NUL term back to "=", to make "param" the whole string. */
241 /* Handle obsolete-style parameters */
242 if (obsolete_checksetup(param
))
245 /* Preemptive maintenance for "why didn't my mispelled command
247 if (strchr(param
, '.') && (!val
|| strchr(param
, '.') < val
)) {
248 printk(KERN_ERR
"Unknown boot option `%s': ignoring\n", param
);
253 /* Environment option */
255 for (i
= 0; envp_init
[i
]; i
++) {
256 if (i
== MAX_INIT_ENVS
)
257 panic("Too many boot env vars at `%s'", param
);
259 envp_init
[i
] = param
;
261 /* Command line option */
263 for (i
= 0; argv_init
[i
]; i
++) {
264 if (i
== MAX_INIT_ARGS
)
265 panic("Too many boot init vars at `%s'",param
);
267 argv_init
[i
] = param
;
272 static int __init
init_setup(char *str
)
276 execute_command
= str
;
277 /* In case LILO is going to boot us with default command line,
278 * it prepends "auto" before the whole cmdline which makes
279 * the shell think it should execute a script with such name.
280 * So we ignore all arguments entered _before_ init=... [MJ]
282 for (i
= 1; i
< MAX_INIT_ARGS
; i
++)
286 __setup("init=", init_setup
);
288 extern void setup_arch(char **);
289 extern void cpu_idle(void);
293 #ifdef CONFIG_X86_LOCAL_APIC
294 static void __init
smp_init(void)
296 APIC_init_uniprocessor();
299 #define smp_init() do { } while (0)
302 static inline void setup_per_cpu_areas(void) { }
303 static inline void smp_prepare_cpus(unsigned int maxcpus
) { }
307 #ifdef __GENERIC_PER_CPU
308 unsigned long __per_cpu_offset
[NR_CPUS
];
310 static void __init
setup_per_cpu_areas(void)
312 unsigned long size
, i
;
314 /* Created by linker magic */
315 extern char __per_cpu_start
[], __per_cpu_end
[];
317 /* Copy section for each CPU (we discard the original) */
318 size
= ALIGN(__per_cpu_end
- __per_cpu_start
, SMP_CACHE_BYTES
);
319 #ifdef CONFIG_MODULES
320 if (size
< PERCPU_ENOUGH_ROOM
)
321 size
= PERCPU_ENOUGH_ROOM
;
324 ptr
= alloc_bootmem(size
* NR_CPUS
);
326 for (i
= 0; i
< NR_CPUS
; i
++, ptr
+= size
) {
327 __per_cpu_offset
[i
] = ptr
- __per_cpu_start
;
328 memcpy(ptr
, __per_cpu_start
, __per_cpu_end
- __per_cpu_start
);
331 #endif /* !__GENERIC_PER_CPU */
333 /* Called by boot processor to activate the rest. */
334 static void __init
smp_init(void)
338 /* FIXME: This should be done in userspace --RR */
339 for (i
= 0; i
< NR_CPUS
; i
++) {
340 if (num_online_cpus() >= max_cpus
)
342 if (cpu_possible(i
) && !cpu_online(i
)) {
343 printk("Bringing up %i\n", i
);
348 /* Any cleanup work */
349 printk("CPUS done %u\n", max_cpus
);
350 smp_cpus_done(max_cpus
);
352 /* Get other processors into their bootup holding patterns. */
362 * We need to finalize in a non-__init function or else race conditions
363 * between the root thread and the init thread may cause start_kernel to
364 * be reaped by free_initmem before the root thread has proceeded to
368 static void rest_init(void)
370 kernel_thread(init
, NULL
, CLONE_KERNEL
);
376 * Activate the first processor.
379 asmlinkage
void __init
start_kernel(void)
382 extern char saved_command_line
[];
383 extern struct kernel_param __start___param
[], __stop___param
[];
385 * Interrupts are still disabled. Do necessary setups, then
389 printk(linux_banner
);
390 setup_arch(&command_line
);
391 setup_per_zone_pages_min();
392 setup_per_cpu_areas();
395 * Mark the boot cpu "online" so that it can call console drivers in
396 * printk() and can access its per-cpu storage.
398 smp_prepare_boot_cpu();
400 build_all_zonelists();
402 printk("Kernel command line: %s\n", saved_command_line
);
403 parse_args("Booting kernel", command_line
, __start___param
,
404 __stop___param
- __start___param
,
405 &unknown_bootoption
);
415 * HACK ALERT! This is early. We're enabling the console before
416 * we've done PCI setups etc, and console_init() must be aware of
417 * this. But we do want output early, in case something goes wrong.
422 #ifdef CONFIG_BLK_DEV_INITRD
423 if (initrd_start
&& !initrd_below_start_ok
&&
424 initrd_start
< min_low_pfn
<< PAGE_SHIFT
) {
425 printk(KERN_CRIT
"initrd overwritten (0x%08lx < 0x%08lx) - "
426 "disabling it.\n",initrd_start
,min_low_pfn
<< PAGE_SHIFT
);
437 pgtable_cache_init();
439 fork_init(num_physpages
);
442 security_scaffolding_startup();
443 vfs_caches_init(num_physpages
);
446 /* rootfs populating might need page-writeback */
447 page_writeback_init();
449 #ifdef CONFIG_PROC_FS
453 printk("POSIX conformance testing by UNIFIX\n");
456 * We count on the initial thread going ok
457 * Like idlers init is an unlocked kernel thread, which will
458 * make syscalls (and thus be locked).
460 init_idle(current
, smp_processor_id());
462 /* Do the rest non-__init'ed, we're now alive */
466 int __initdata initcall_debug
;
468 static int __init
initcall_debug_setup(char *str
)
473 __setup("initcall_debug", initcall_debug_setup
);
475 struct task_struct
*child_reaper
= &init_task
;
477 extern initcall_t __initcall_start
, __initcall_end
;
479 static void __init
do_initcalls(void)
482 int count
= preempt_count();
484 for (call
= &__initcall_start
; call
< &__initcall_end
; call
++) {
488 printk("calling initcall 0x%p\n", *call
);
493 if (preempt_count() != count
) {
494 msg
= "preemption imbalance";
495 preempt_count() = count
;
497 if (irqs_disabled()) {
498 msg
= "disabled interrupts";
502 printk("error in initcall at 0x%p: "
503 "returned with %s\n", *call
, msg
);
507 /* Make sure there is no pending stuff from the initcall sequence */
508 flush_scheduled_work();
512 * Ok, the machine is now initialized. None of the devices
513 * have been touched yet, but the CPU subsystem is up and
514 * running, and memory and process management works.
516 * Now we can finally start doing some real work..
518 static void __init
do_basic_setup(void)
526 /* Networking initialization needs a process context */
533 static void do_pre_smp_initcalls(void)
535 extern int spawn_ksoftirqd(void);
537 extern int migration_init(void);
541 node_nr_running_init();
545 extern void prepare_namespace(void);
547 static int init(void * unused
)
549 static char * argv_sh
[] = { "sh", NULL
, };
553 * Tell the world that we're going to be the grim
554 * reaper of innocent orphaned children.
556 * We don't want people to have to make incorrect
557 * assumptions about where in the task array this
560 child_reaper
= current
;
562 /* Sets up cpus_possible() */
563 smp_prepare_cpus(max_cpus
);
565 do_pre_smp_initcalls();
573 * Ok, we have completed the initial bootup, and
574 * we're essentially up and running. Get rid of the
575 * initmem segments and start the user-mode stuff..
581 if (open("/dev/console", O_RDWR
, 0) < 0)
582 printk("Warning: unable to open an initial console.\n");
588 * We try each of these until one succeeds.
590 * The Bourne shell can be used instead of init if we are
591 * trying to recover a really broken machine.
595 execve(execute_command
,argv_init
,envp_init
);
596 execve("/sbin/init",argv_init
,envp_init
);
597 execve("/etc/init",argv_init
,envp_init
);
598 execve("/bin/init",argv_init
,envp_init
);
599 execve("/bin/sh",argv_sh
,envp_init
);
600 panic("No init found. Try passing init= option to kernel.");