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/types.h>
16 #include <linux/module.h>
17 #include <linux/proc_fs.h>
18 #include <linux/devfs_fs_kernel.h>
19 #include <linux/kernel.h>
20 #include <linux/syscalls.h>
21 #include <linux/string.h>
22 #include <linux/ctype.h>
23 #include <linux/delay.h>
24 #include <linux/utsname.h>
25 #include <linux/ioport.h>
26 #include <linux/init.h>
27 #include <linux/smp_lock.h>
28 #include <linux/initrd.h>
29 #include <linux/hdreg.h>
30 #include <linux/bootmem.h>
31 #include <linux/tty.h>
32 #include <linux/gfp.h>
33 #include <linux/percpu.h>
34 #include <linux/kernel_stat.h>
35 #include <linux/security.h>
36 #include <linux/workqueue.h>
37 #include <linux/profile.h>
38 #include <linux/rcupdate.h>
39 #include <linux/moduleparam.h>
40 #include <linux/kallsyms.h>
41 #include <linux/writeback.h>
42 #include <linux/cpu.h>
43 #include <linux/efi.h>
44 #include <linux/unistd.h>
50 * This is one of the first .c files built. Error out early
51 * if we have compiler trouble..
53 #if __GNUC__ == 2 && __GNUC_MINOR__ == 96
54 #ifdef CONFIG_FRAME_POINTER
55 #error This compiler cannot compile correctly with frame pointers enabled
59 #ifdef CONFIG_X86_LOCAL_APIC
64 * Versions of gcc older than that listed below may actually compile
65 * and link okay, but the end product can have subtle run time bugs.
66 * To avoid associated bogus bug reports, we flatly refuse to compile
67 * with a gcc that is known to be too old from the very beginning.
69 #if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 95)
70 #error Sorry, your GCC is too old. It builds incorrect kernels.
73 extern char *linux_banner;
75 static int init(void *);
77 extern void init_IRQ(void);
78 extern void sock_init(void);
79 extern void fork_init(unsigned long);
80 extern void mca_init(void);
81 extern void sbus_init(void);
82 extern void sysctl_init(void);
83 extern void signals_init(void);
84 extern void buffer_init(void);
85 extern void pidhash_init(void);
86 extern void pidmap_init(void);
87 extern void pte_chain_init(void);
88 extern void radix_tree_init(void);
89 extern void free_initmem(void);
90 extern void populate_rootfs(void);
91 extern void driver_init(void);
92 extern void prepare_namespace(void);
95 extern void tc_init(void);
98 int system_state; /* SYSTEM_BOOTING/RUNNING/SHUTDOWN */
101 * Boot command-line arguments
103 #define MAX_INIT_ARGS 8
104 #define MAX_INIT_ENVS 8
106 extern void time_init(void);
107 /* Default late time init is NULL. archs can override this later. */
108 void (*late_time_init)(void);
109 extern void softirq_init(void);
111 static 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, };
144 static const char *panic_later, *panic_param;
146 __setup("profile=", profile_setup);
148 static int __init obsolete_checksetup(char *line)
150 struct obs_kernel_param *p;
151 extern struct obs_kernel_param __setup_start, __setup_end;
155 int n = strlen(p->str);
156 if (!strncmp(line, p->str, n)) {
157 if (!p->setup_func) {
158 printk(KERN_WARNING "Parameter %s is obsolete, ignored\n", p->str);
160 } else if (p->setup_func(line + n))
164 } while (p < &__setup_end);
168 /* this should be approx 2 Bo*oMips to start (note initial shift), and will
169 still work even if initially too large, it will just take slightly longer */
170 unsigned long loops_per_jiffy = (1<<12);
173 EXPORT_SYMBOL(loops_per_jiffy);
176 /* This is the number of bits of precision for the loops_per_jiffy. Each
177 bit takes on average 1.5/HZ seconds. This (like the original) is a little
181 void __init calibrate_delay(void)
183 unsigned long ticks, loopbit;
184 int lps_precision = LPS_PREC;
186 loops_per_jiffy = (1<<12);
188 printk("Calibrating delay loop... ");
189 while (loops_per_jiffy <<= 1) {
190 /* wait for "start of" clock tick */
192 while (ticks == jiffies)
196 __delay(loops_per_jiffy);
197 ticks = jiffies - ticks;
202 /* Do a binary approximation to get loops_per_jiffy set to equal one clock
203 (up to lps_precision bits) */
204 loops_per_jiffy >>= 1;
205 loopbit = loops_per_jiffy;
206 while ( lps_precision-- && (loopbit >>= 1) ) {
207 loops_per_jiffy |= loopbit;
209 while (ticks == jiffies);
211 __delay(loops_per_jiffy);
212 if (jiffies != ticks) /* longer than 1 tick */
213 loops_per_jiffy &= ~loopbit;
216 /* Round the value and print it */
217 printk("%lu.%02lu BogoMIPS\n",
218 loops_per_jiffy/(500000/HZ),
219 (loops_per_jiffy/(5000/HZ)) % 100);
222 static int __init debug_kernel(char *str)
226 console_loglevel = 10;
230 static int __init quiet_kernel(char *str)
234 console_loglevel = 4;
238 __setup("debug", debug_kernel);
239 __setup("quiet", quiet_kernel);
241 /* Unknown boot options get handed to init, unless they look like
243 static int __init unknown_bootoption(char *param, char *val)
245 /* Change NUL term back to "=", to make "param" the whole string. */
249 /* Handle obsolete-style parameters */
250 if (obsolete_checksetup(param))
253 /* Preemptive maintenance for "why didn't my mispelled command
255 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
256 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
264 /* Environment option */
266 for (i = 0; envp_init[i]; i++) {
267 if (i == MAX_INIT_ENVS) {
268 panic_later = "Too many boot env vars at `%s'";
272 envp_init[i] = param;
274 /* Command line option */
276 for (i = 0; argv_init[i]; i++) {
277 if (i == MAX_INIT_ARGS) {
278 panic_later = "Too many boot init vars at `%s'";
282 argv_init[i] = param;
287 static int __init init_setup(char *str)
291 execute_command = str;
292 /* In case LILO is going to boot us with default command line,
293 * it prepends "auto" before the whole cmdline which makes
294 * the shell think it should execute a script with such name.
295 * So we ignore all arguments entered _before_ init=... [MJ]
297 for (i = 1; i < MAX_INIT_ARGS; i++)
301 __setup("init=", init_setup);
303 extern void setup_arch(char **);
304 extern void cpu_idle(void);
308 #ifdef CONFIG_X86_LOCAL_APIC
309 static void __init smp_init(void)
311 APIC_init_uniprocessor();
314 #define smp_init() do { } while (0)
317 static inline void setup_per_cpu_areas(void) { }
318 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
322 #ifdef __GENERIC_PER_CPU
323 unsigned long __per_cpu_offset[NR_CPUS];
325 EXPORT_SYMBOL(__per_cpu_offset);
327 static void __init setup_per_cpu_areas(void)
329 unsigned long size, i;
331 /* Created by linker magic */
332 extern char __per_cpu_start[], __per_cpu_end[];
334 /* Copy section for each CPU (we discard the original) */
335 size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
336 #ifdef CONFIG_MODULES
337 if (size < PERCPU_ENOUGH_ROOM)
338 size = PERCPU_ENOUGH_ROOM;
341 ptr = alloc_bootmem(size * NR_CPUS);
343 for (i = 0; i < NR_CPUS; i++, ptr += size) {
344 __per_cpu_offset[i] = ptr - __per_cpu_start;
345 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
348 #endif /* !__GENERIC_PER_CPU */
350 /* Called by boot processor to activate the rest. */
351 static void __init smp_init(void)
356 /* FIXME: This should be done in userspace --RR */
357 for (i = 0; i < NR_CPUS; i++) {
358 if (num_online_cpus() >= max_cpus)
360 if (cpu_possible(i) && !cpu_online(i)) {
366 /* Any cleanup work */
367 printk("Brought up %u CPUs\n", j);
368 smp_cpus_done(max_cpus);
370 /* Get other processors into their bootup holding patterns. */
380 * We need to finalize in a non-__init function or else race conditions
381 * between the root thread and the init thread may cause start_kernel to
382 * be reaped by free_initmem before the root thread has proceeded to
385 * gcc-3.4 accidentally inlines this function, so use noinline.
388 static void noinline rest_init(void)
390 kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
396 * Activate the first processor.
399 asmlinkage void __init start_kernel(void)
402 extern char saved_command_line[];
403 extern struct kernel_param __start___param[], __stop___param[];
405 * Interrupts are still disabled. Do necessary setups, then
410 printk(linux_banner);
411 setup_arch(&command_line);
412 setup_per_cpu_areas();
415 * Mark the boot cpu "online" so that it can call console drivers in
416 * printk() and can access its per-cpu storage.
418 smp_prepare_boot_cpu();
420 build_all_zonelists();
422 printk("Kernel command line: %s\n", saved_command_line);
423 parse_args("Booting kernel", command_line, __start___param,
424 __stop___param - __start___param,
425 &unknown_bootoption);
436 * HACK ALERT! This is early. We're enabling the console before
437 * we've done PCI setups etc, and console_init() must be aware of
438 * this. But we do want output early, in case something goes wrong.
442 panic(panic_later, panic_param);
445 #ifdef CONFIG_BLK_DEV_INITRD
446 if (initrd_start && !initrd_below_start_ok &&
447 initrd_start < min_low_pfn << PAGE_SHIFT) {
448 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
449 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
459 pgtable_cache_init();
463 efi_enter_virtual_mode();
465 fork_init(num_physpages);
469 security_scaffolding_startup();
470 vfs_caches_init(num_physpages);
473 /* rootfs populating might need page-writeback */
474 page_writeback_init();
475 #ifdef CONFIG_PROC_FS
479 printk("POSIX conformance testing by UNIFIX\n");
482 * We count on the initial thread going ok
483 * Like idlers init is an unlocked kernel thread, which will
484 * make syscalls (and thus be locked).
486 init_idle(current, smp_processor_id());
488 /* Do the rest non-__init'ed, we're now alive */
492 static int __initdata initcall_debug;
494 static int __init initcall_debug_setup(char *str)
499 __setup("initcall_debug", initcall_debug_setup);
501 struct task_struct *child_reaper = &init_task;
503 extern initcall_t __initcall_start, __initcall_end;
505 static void __init do_initcalls(void)
508 int count = preempt_count();
510 for (call = &__initcall_start; call < &__initcall_end; call++) {
513 if (initcall_debug) {
514 printk(KERN_DEBUG "Calling initcall 0x%p", *call);
515 print_symbol(": %s()", (unsigned long) *call);
522 if (preempt_count() != count) {
523 msg = "preemption imbalance";
524 preempt_count() = count;
526 if (irqs_disabled()) {
527 msg = "disabled interrupts";
531 printk("error in initcall at 0x%p: "
532 "returned with %s\n", *call, msg);
536 /* Make sure there is no pending stuff from the initcall sequence */
537 flush_scheduled_work();
541 * Ok, the machine is now initialized. None of the devices
542 * have been touched yet, but the CPU subsystem is up and
543 * running, and memory and process management works.
545 * Now we can finally start doing some real work..
547 static void __init do_basic_setup(void)
555 /* Networking initialization needs a process context */
562 static void do_pre_smp_initcalls(void)
564 extern int spawn_ksoftirqd(void);
566 extern int migration_init(void);
570 node_nr_running_init();
574 static void run_init_process(char *init_filename)
576 argv_init[0] = init_filename;
577 execve(init_filename, argv_init, envp_init);
580 static int init(void * unused)
584 * Tell the world that we're going to be the grim
585 * reaper of innocent orphaned children.
587 * We don't want people to have to make incorrect
588 * assumptions about where in the task array this
591 child_reaper = current;
593 /* Sets up cpus_possible() */
594 smp_prepare_cpus(max_cpus);
596 do_pre_smp_initcalls();
601 * Do this before initcalls, because some drivers want to access
609 * check if there is an early userspace init. If yes, let it do all
612 if (sys_access("/init", 0) == 0)
613 execute_command = "/init";
618 * Ok, we have completed the initial bootup, and
619 * we're essentially up and running. Get rid of the
620 * initmem segments and start the user-mode stuff..
624 system_state = SYSTEM_RUNNING;
626 if (sys_open("/dev/console", O_RDWR, 0) < 0)
627 printk("Warning: unable to open an initial console.\n");
633 * We try each of these until one succeeds.
635 * The Bourne shell can be used instead of init if we are
636 * trying to recover a really broken machine.
640 run_init_process(execute_command);
642 run_init_process("/sbin/init");
643 run_init_process("/etc/init");
644 run_init_process("/bin/init");
645 run_init_process("/bin/sh");
647 panic("No init found. Try passing init= option to kernel.");