1 /*
2 * linux/init/main.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
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>
10 */
11
12 #define __KERNEL_SYSCALLS__
13
14 #include <linux/config.h>
15 #include <linux/proc_fs.h>
16 #include <linux/devfs_fs_kernel.h>
17 #include <linux/unistd.h>
18 #include <linux/string.h>
19 #include <linux/ctype.h>
20 #include <linux/delay.h>
21 #include <linux/utsname.h>
22 #include <linux/ioport.h>
23 #include <linux/init.h>
24 #include <linux/smp_lock.h>
25 #include <linux/blk.h>
26 #include <linux/hdreg.h>
27 #include <linux/iobuf.h>
28 #include <linux/bootmem.h>
29 #include <linux/file.h>
30 #include <linux/tty.h>
31
32 #include <asm/io.h>
33 #include <asm/bugs.h>
34
35 #if defined(CONFIG_ARCH_S390)
36 #include <asm/s390mach.h>
37 #include <asm/ccwcache.h>
38 #endif
39
40 #ifdef CONFIG_ACPI
41 #include <linux/acpi.h>
42 #endif
43
44 #ifdef CONFIG_PCI
45 #include <linux/pci.h>
46 #endif
47
48 #ifdef CONFIG_DIO
49 #include <linux/dio.h>
50 #endif
51
52 #ifdef CONFIG_ZORRO
53 #include <linux/zorro.h>
54 #endif
55
56 #ifdef CONFIG_MTRR
57 # include <asm/mtrr.h>
58 #endif
59
60 #ifdef CONFIG_NUBUS
61 #include <linux/nubus.h>
62 #endif
63
64 #ifdef CONFIG_ISAPNP
65 #include <linux/isapnp.h>
66 #endif
67
68 #ifdef CONFIG_IRDA
69 extern int irda_proto_init(void);
70 extern int irda_device_init(void);
71 #endif
72
73 #ifdef CONFIG_X86_LOCAL_APIC
74 #include <asm/smp.h>
75 #endif
76
77 /*
78 * Versions of gcc older than that listed below may actually compile
79 * and link okay, but the end product can have subtle run time bugs.
80 * To avoid associated bogus bug reports, we flatly refuse to compile
81 * with a gcc that is known to be too old from the very beginning.
82 */
83 #if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 91)
84 #error Sorry, your GCC is too old. It builds incorrect kernels.
85 #endif
86
87 extern char _stext, _etext;
88 extern char *linux_banner;
89
90 static int init(void *);
91
92 extern void init_IRQ(void);
93 extern void init_modules(void);
94 extern void sock_init(void);
95 extern void fork_init(unsigned long);
96 extern void mca_init(void);
97 extern void sbus_init(void);
98 extern void ppc_init(void);
99 extern void sysctl_init(void);
100 extern void signals_init(void);
101 extern int init_pcmcia_ds(void);
102
103 extern void free_initmem(void);
104 #ifdef CONFIG_ACPI_BUS
105 extern void acpi_early_init(void);
106 #else
acpi_early_init(void)107 static inline void acpi_early_init(void) { }
108 #endif
109
110 #ifdef CONFIG_TC
111 extern void tc_init(void);
112 #endif
113
114 extern void ecard_init(void);
115
116 #if defined(CONFIG_SYSVIPC)
117 extern void ipc_init(void);
118 #endif
119
120 /*
121 * Boot command-line arguments
122 */
123 #define MAX_INIT_ARGS 8
124 #define MAX_INIT_ENVS 8
125
126 extern void time_init(void);
127 extern void softirq_init(void);
128
129 int rows, cols;
130
131 char *execute_command;
132
133 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
134 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
135
profile_setup(char * str)136 static int __init profile_setup(char *str)
137 {
138 int par;
139 if (get_option(&str,&par)) prof_shift = par;
140 return 1;
141 }
142
143 __setup("profile=", profile_setup);
144
checksetup(char * line)145 static int __init checksetup(char *line)
146 {
147 struct kernel_param *p;
148
149 p = &__setup_start;
150 do {
151 int n = strlen(p->str);
152 if (!strncmp(line,p->str,n)) {
153 if (p->setup_func(line+n))
154 return 1;
155 }
156 p++;
157 } while (p < &__setup_end);
158 return 0;
159 }
160
161 /* this should be approx 2 Bo*oMips to start (note initial shift), and will
162 still work even if initially too large, it will just take slightly longer */
163 unsigned long loops_per_jiffy = (1<<12);
164
165 /* This is the number of bits of precision for the loops_per_jiffy. Each
166 bit takes on average 1.5/HZ seconds. This (like the original) is a little
167 better than 1% */
168 #define LPS_PREC 8
169
calibrate_delay(void)170 void __init calibrate_delay(void)
171 {
172 unsigned long ticks, loopbit;
173 int lps_precision = LPS_PREC;
174
175 loops_per_jiffy = (1<<12);
176
177 printk("Calibrating delay loop... ");
178 while (loops_per_jiffy <<= 1) {
179 /* wait for "start of" clock tick */
180 ticks = jiffies;
181 while (ticks == jiffies)
182 /* nothing */;
183 /* Go .. */
184 ticks = jiffies;
185 __delay(loops_per_jiffy);
186 ticks = jiffies - ticks;
187 if (ticks)
188 break;
189 }
190
191 /* Do a binary approximation to get loops_per_jiffy set to equal one clock
192 (up to lps_precision bits) */
193 loops_per_jiffy >>= 1;
194 loopbit = loops_per_jiffy;
195 while ( lps_precision-- && (loopbit >>= 1) ) {
196 loops_per_jiffy |= loopbit;
197 ticks = jiffies;
198 while (ticks == jiffies);
199 ticks = jiffies;
200 __delay(loops_per_jiffy);
201 if (jiffies != ticks) /* longer than 1 tick */
202 loops_per_jiffy &= ~loopbit;
203 }
204
205 /* Round the value and print it */
206 printk("%lu.%02lu BogoMIPS\n",
207 loops_per_jiffy/(500000/HZ),
208 (loops_per_jiffy/(5000/HZ)) % 100);
209 }
210
debug_kernel(char * str)211 static int __init debug_kernel(char *str)
212 {
213 if (*str)
214 return 0;
215 console_loglevel = 10;
216 return 1;
217 }
218
quiet_kernel(char * str)219 static int __init quiet_kernel(char *str)
220 {
221 if (*str)
222 return 0;
223 console_loglevel = 4;
224 return 1;
225 }
226
227 __setup("debug", debug_kernel);
228 __setup("quiet", quiet_kernel);
229
230 /*
231 * This is a simple kernel command line parsing function: it parses
232 * the command line, and fills in the arguments/environment to init
233 * as appropriate. Any cmd-line option is taken to be an environment
234 * variable if it contains the character '='.
235 *
236 * This routine also checks for options meant for the kernel.
237 * These options are not given to init - they are for internal kernel use only.
238 */
parse_options(char * line)239 static void __init parse_options(char *line)
240 {
241 char *next,*quote;
242 int args, envs;
243
244 if (!*line)
245 return;
246 args = 0;
247 envs = 1; /* TERM is set to 'linux' by default */
248 next = line;
249 while ((line = next) != NULL) {
250 quote = strchr(line,'"');
251 next = strchr(line, ' ');
252 while (next != NULL && quote != NULL && quote < next) {
253 /* we found a left quote before the next blank
254 * now we have to find the matching right quote
255 */
256 next = strchr(quote+1, '"');
257 if (next != NULL) {
258 quote = strchr(next+1, '"');
259 next = strchr(next+1, ' ');
260 }
261 }
262 if (next != NULL)
263 *next++ = 0;
264 if (!strncmp(line,"init=",5)) {
265 line += 5;
266 execute_command = line;
267 /* In case LILO is going to boot us with default command line,
268 * it prepends "auto" before the whole cmdline which makes
269 * the shell think it should execute a script with such name.
270 * So we ignore all arguments entered _before_ init=... [MJ]
271 */
272 args = 0;
273 continue;
274 }
275 if (checksetup(line))
276 continue;
277
278 /*
279 * Then check if it's an environment variable or
280 * an option.
281 */
282 if (strchr(line,'=')) {
283 if (envs >= MAX_INIT_ENVS)
284 break;
285 envp_init[++envs] = line;
286 } else {
287 if (args >= MAX_INIT_ARGS)
288 break;
289 if (*line)
290 argv_init[++args] = line;
291 }
292 }
293 argv_init[args+1] = NULL;
294 envp_init[envs+1] = NULL;
295 }
296
297
298 extern void setup_arch(char **);
299 extern void cpu_idle(void);
300
301 unsigned long wait_init_idle;
302
303 #ifndef CONFIG_SMP
304
305 #ifdef CONFIG_X86_LOCAL_APIC
smp_init(void)306 static void __init smp_init(void)
307 {
308 APIC_init_uniprocessor();
309 }
310 #else
311 #define smp_init() do { } while (0)
312 #endif
313
314 #else
315
316
317 /* Called by boot processor to activate the rest. */
smp_init(void)318 static void __init smp_init(void)
319 {
320 /* Get other processors into their bootup holding patterns. */
321 smp_boot_cpus();
322 wait_init_idle = cpu_online_map;
323 clear_bit(current->processor, &wait_init_idle); /* Don't wait on me! */
324
325 smp_threads_ready=1;
326 smp_commence();
327
328 /* Wait for the other cpus to set up their idle processes */
329 printk("Waiting on wait_init_idle (map = 0x%lx)\n", wait_init_idle);
330 while (wait_init_idle) {
331 cpu_relax();
332 barrier();
333 }
334 printk("All processors have done init_idle\n");
335 }
336
337 #endif
338
339 /*
340 * We need to finalize in a non-__init function or else race conditions
341 * between the root thread and the init thread may cause start_kernel to
342 * be reaped by free_initmem before the root thread has proceeded to
343 * cpu_idle.
344 */
345
rest_init(void)346 static void rest_init(void)
347 {
348 kernel_thread(init, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGNAL);
349 unlock_kernel();
350 current->need_resched = 1;
351 cpu_idle();
352 }
353
354 /*
355 * Activate the first processor.
356 */
357
start_kernel(void)358 asmlinkage void __init start_kernel(void)
359 {
360 char * command_line;
361 extern char saved_command_line[];
362 /*
363 * Interrupts are still disabled. Do necessary setups, then
364 * enable them
365 */
366 lock_kernel();
367 printk(linux_banner);
368 setup_arch(&command_line);
369 printk("Kernel command line: %s\n", saved_command_line);
370 parse_options(command_line);
371 trap_init();
372 init_IRQ();
373 sched_init();
374 softirq_init();
375 time_init();
376
377 /*
378 * HACK ALERT! This is early. We're enabling the console before
379 * we've done PCI setups etc, and console_init() must be aware of
380 * this. But we do want output early, in case something goes wrong.
381 */
382 console_init();
383 #ifdef CONFIG_MODULES
384 init_modules();
385 #endif
386 if (prof_shift) {
387 unsigned int size;
388 /* only text is profiled */
389 prof_len = (unsigned long) &_etext - (unsigned long) &_stext;
390 prof_len >>= prof_shift;
391
392 size = prof_len * sizeof(unsigned int) + PAGE_SIZE-1;
393 prof_buffer = (unsigned int *) alloc_bootmem(size);
394 }
395
396 kmem_cache_init();
397 sti();
398 calibrate_delay();
399 #ifdef CONFIG_BLK_DEV_INITRD
400 if (initrd_start && !initrd_below_start_ok &&
401 initrd_start < min_low_pfn << PAGE_SHIFT) {
402 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
403 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
404 initrd_start = 0;
405 }
406 #endif
407 mem_init();
408 kmem_cache_sizes_init();
409 pgtable_cache_init();
410
411 /*
412 * For architectures that have highmem, num_mappedpages represents
413 * the amount of memory the kernel can use. For other architectures
414 * it's the same as the total pages. We need both numbers because
415 * some subsystems need to initialize based on how much memory the
416 * kernel can use.
417 */
418 if (num_mappedpages == 0)
419 num_mappedpages = num_physpages;
420
421 fork_init(num_mappedpages);
422 proc_caches_init();
423 vfs_caches_init(num_physpages);
424 buffer_init(num_physpages);
425 page_cache_init(num_physpages);
426 #if defined(CONFIG_ARCH_S390)
427 ccwcache_init();
428 #endif
429 signals_init();
430 #ifdef CONFIG_PROC_FS
431 proc_root_init();
432 #endif
433 check_bugs();
434 acpi_early_init(); /* before LAPIC and SMP init */
435 printk("POSIX conformance testing by UNIFIX\n");
436
437 /*
438 * We count on the initial thread going ok
439 * Like idlers init is an unlocked kernel thread, which will
440 * make syscalls (and thus be locked).
441 */
442 smp_init();
443 #if defined(CONFIG_SYSVIPC)
444 ipc_init();
445 #endif
446 rest_init();
447 }
448
449 struct task_struct *child_reaper = &init_task;
450
do_initcalls(void)451 static void __init do_initcalls(void)
452 {
453 initcall_t *call;
454
455 call = &__initcall_start;
456 do {
457 (*call)();
458 call++;
459 } while (call < &__initcall_end);
460
461 /* Make sure there is no pending stuff from the initcall sequence */
462 flush_scheduled_tasks();
463 }
464
465 /*
466 * Ok, the machine is now initialized. None of the devices
467 * have been touched yet, but the CPU subsystem is up and
468 * running, and memory and process management works.
469 *
470 * Now we can finally start doing some real work..
471 */
do_basic_setup(void)472 static void __init do_basic_setup(void)
473 {
474
475 /*
476 * Tell the world that we're going to be the grim
477 * reaper of innocent orphaned children.
478 *
479 * We don't want people to have to make incorrect
480 * assumptions about where in the task array this
481 * can be found.
482 */
483 child_reaper = current;
484
485 #if defined(CONFIG_MTRR) /* Do this after SMP initialization */
486 /*
487 * We should probably create some architecture-dependent "fixup after
488 * everything is up" style function where this would belong better
489 * than in init/main.c..
490 */
491 mtrr_init();
492 #endif
493
494 #ifdef CONFIG_SYSCTL
495 sysctl_init();
496 #endif
497
498 /*
499 * Ok, at this point all CPU's should be initialized, so
500 * we can start looking into devices..
501 */
502 #if defined(CONFIG_ARCH_S390)
503 s390_init_machine_check();
504 #endif
505 #ifdef CONFIG_ACPI_INTERPRETER
506 acpi_init();
507 #endif
508 #ifdef CONFIG_PCI
509 pci_init();
510 #endif
511 #ifdef CONFIG_SBUS
512 sbus_init();
513 #endif
514 #if defined(CONFIG_PPC)
515 ppc_init();
516 #endif
517 #ifdef CONFIG_MCA
518 mca_init();
519 #endif
520 #ifdef CONFIG_ARCH_ACORN
521 ecard_init();
522 #endif
523 #ifdef CONFIG_ZORRO
524 zorro_init();
525 #endif
526 #ifdef CONFIG_DIO
527 dio_init();
528 #endif
529 #ifdef CONFIG_NUBUS
530 nubus_init();
531 #endif
532 #ifdef CONFIG_ISAPNP
533 isapnp_init();
534 #endif
535 #ifdef CONFIG_TC
536 tc_init();
537 #endif
538
539 /* Networking initialization needs a process context */
540 sock_init();
541
542 start_context_thread();
543 do_initcalls();
544
545 #ifdef CONFIG_IRDA
546 irda_proto_init();
547 irda_device_init(); /* Must be done after protocol initialization */
548 #endif
549 #ifdef CONFIG_PCMCIA
550 init_pcmcia_ds(); /* Do this last */
551 #endif
552 }
553
run_init_process(char * init_filename)554 static void run_init_process(char *init_filename)
555 {
556 argv_init[0] = init_filename;
557 execve(init_filename, argv_init, envp_init);
558 }
559
560 extern void prepare_namespace(void);
561
init(void * unused)562 static int init(void * unused)
563 {
564 struct files_struct *files;
565 lock_kernel();
566 do_basic_setup();
567
568 prepare_namespace();
569
570 /*
571 * Ok, we have completed the initial bootup, and
572 * we're essentially up and running. Get rid of the
573 * initmem segments and start the user-mode stuff..
574 */
575 free_initmem();
576 unlock_kernel();
577
578 /*
579 * Right now we are a thread sharing with a ton of kernel
580 * stuff. We don't want to end up in user space in that state
581 */
582
583 files = current->files;
584 if(unshare_files())
585 panic("unshare");
586 put_files_struct(files);
587
588 if (open("/dev/console", O_RDWR, 0) < 0)
589 printk("Warning: unable to open an initial console.\n");
590
591 (void) dup(0);
592 (void) dup(0);
593
594 /*
595 * We try each of these until one succeeds.
596 *
597 * The Bourne shell can be used instead of init if we are
598 * trying to recover a really broken machine.
599 */
600
601 if (execute_command)
602 run_init_process(execute_command);
603
604 run_init_process("/sbin/init");
605 run_init_process("/etc/init");
606 run_init_process("/bin/init");
607 run_init_process("/bin/sh");
608
609 panic("No init found. Try passing init= option to kernel.");
610 }
611