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/kmod.h>
35 #include <linux/kernel_stat.h>
36 #include <linux/security.h>
37 #include <linux/workqueue.h>
38 #include <linux/profile.h>
39 #include <linux/rcupdate.h>
40 #include <linux/moduleparam.h>
41 #include <linux/kallsyms.h>
42 #include <linux/writeback.h>
43 #include <linux/cpu.h>
44 #include <linux/cpuset.h>
45 #include <linux/efi.h>
46 #include <linux/unistd.h>
47 #include <linux/rmap.h>
48 #include <linux/mempolicy.h>
49 #include <linux/key.h>
53 #include <asm/setup.h>
56 * This is one of the first .c files built. Error out early
57 * if we have compiler trouble..
59 #if __GNUC__ == 2 && __GNUC_MINOR__ == 96
60 #ifdef CONFIG_FRAME_POINTER
61 #error This compiler cannot compile correctly with frame pointers enabled
65 #ifdef CONFIG_X86_LOCAL_APIC
70 * Versions of gcc older than that listed below may actually compile
71 * and link okay, but the end product can have subtle run time bugs.
72 * To avoid associated bogus bug reports, we flatly refuse to compile
73 * with a gcc that is known to be too old from the very beginning.
75 #if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 95)
76 #error Sorry, your GCC is too old. It builds incorrect kernels.
79 static int init(void *);
81 extern void init_IRQ(void);
82 extern void sock_init(void);
83 extern void fork_init(unsigned long);
84 extern void mca_init(void);
85 extern void sbus_init(void);
86 extern void sysctl_init(void);
87 extern void signals_init(void);
88 extern void buffer_init(void);
89 extern void pidhash_init(void);
90 extern void pidmap_init(void);
91 extern void prio_tree_init(void);
92 extern void radix_tree_init(void);
93 extern void free_initmem(void);
94 extern void populate_rootfs(void);
95 extern void driver_init(void);
96 extern void prepare_namespace(void);
98 extern void acpi_early_init(void);
100 static inline void acpi_early_init(void) { }
104 extern void tc_init(void);
107 enum system_states system_state;
108 EXPORT_SYMBOL(system_state);
111 * Boot command-line arguments
113 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
114 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
116 extern void time_init(void);
117 /* Default late time init is NULL. archs can override this later. */
118 void (*late_time_init)(void);
119 extern void softirq_init(void);
121 /* Untouched command line (eg. for /proc) saved by arch-specific code. */
122 char saved_command_line[COMMAND_LINE_SIZE];
124 static char *execute_command;
126 /* Setup configured maximum number of CPUs to activate */
127 static unsigned int max_cpus = NR_CPUS;
130 * Setup routine for controlling SMP activation
132 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
133 * activation entirely (the MPS table probe still happens, though).
135 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
136 * greater than 0, limits the maximum number of CPUs activated in
139 static int __init nosmp(char *str)
145 __setup("nosmp", nosmp);
147 static int __init maxcpus(char *str)
149 get_option(&str, &max_cpus);
153 __setup("maxcpus=", maxcpus);
155 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
156 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
157 static const char *panic_later, *panic_param;
159 extern struct obs_kernel_param __setup_start[], __setup_end[];
161 static int __init obsolete_checksetup(char *line)
163 struct obs_kernel_param *p;
167 int n = strlen(p->str);
168 if (!strncmp(line, p->str, n)) {
170 /* Already done in parse_early_param? (Needs
171 * exact match on param part) */
172 if (line[n] == '\0' || line[n] == '=')
174 } else if (!p->setup_func) {
175 printk(KERN_WARNING "Parameter %s is obsolete,"
176 " ignored\n", p->str);
178 } else if (p->setup_func(line + n))
182 } while (p < __setup_end);
187 * This should be approx 2 Bo*oMips to start (note initial shift), and will
188 * still work even if initially too large, it will just take slightly longer
190 unsigned long loops_per_jiffy = (1<<12);
192 EXPORT_SYMBOL(loops_per_jiffy);
194 static int __init debug_kernel(char *str)
198 console_loglevel = 10;
202 static int __init quiet_kernel(char *str)
206 console_loglevel = 4;
210 __setup("debug", debug_kernel);
211 __setup("quiet", quiet_kernel);
213 static int __init loglevel(char *str)
215 get_option(&str, &console_loglevel);
219 __setup("loglevel=", loglevel);
222 * Unknown boot options get handed to init, unless they look like
225 static int __init unknown_bootoption(char *param, char *val)
227 /* Change NUL term back to "=", to make "param" the whole string. */
229 /* param=val or param="val"? */
230 if (val == param+strlen(param)+1)
232 else if (val == param+strlen(param)+2) {
234 memmove(val-1, val, strlen(val)+1);
240 /* Handle obsolete-style parameters */
241 if (obsolete_checksetup(param))
245 * Preemptive maintenance for "why didn't my mispelled command
248 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
249 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
257 /* Environment option */
259 for (i = 0; envp_init[i]; i++) {
260 if (i == MAX_INIT_ENVS) {
261 panic_later = "Too many boot env vars at `%s'";
264 if (!strncmp(param, envp_init[i], val - param))
267 envp_init[i] = param;
269 /* Command line option */
271 for (i = 0; argv_init[i]; i++) {
272 if (i == MAX_INIT_ARGS) {
273 panic_later = "Too many boot init vars at `%s'";
277 argv_init[i] = param;
282 static int __init init_setup(char *str)
286 execute_command = str;
288 * In case LILO is going to boot us with default command line,
289 * it prepends "auto" before the whole cmdline which makes
290 * the shell think it should execute a script with such name.
291 * So we ignore all arguments entered _before_ init=... [MJ]
293 for (i = 1; i < MAX_INIT_ARGS; i++)
297 __setup("init=", init_setup);
299 extern void setup_arch(char **);
303 #ifdef CONFIG_X86_LOCAL_APIC
304 static void __init smp_init(void)
306 APIC_init_uniprocessor();
309 #define smp_init() do { } while (0)
312 static inline void setup_per_cpu_areas(void) { }
313 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
317 #ifdef __GENERIC_PER_CPU
318 unsigned long __per_cpu_offset[NR_CPUS];
320 EXPORT_SYMBOL(__per_cpu_offset);
322 static void __init setup_per_cpu_areas(void)
324 unsigned long size, i;
326 /* Created by linker magic */
327 extern char __per_cpu_start[], __per_cpu_end[];
329 /* Copy section for each CPU (we discard the original) */
330 size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
331 #ifdef CONFIG_MODULES
332 if (size < PERCPU_ENOUGH_ROOM)
333 size = PERCPU_ENOUGH_ROOM;
336 ptr = alloc_bootmem(size * NR_CPUS);
338 for (i = 0; i < NR_CPUS; i++, ptr += size) {
339 __per_cpu_offset[i] = ptr - __per_cpu_start;
340 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
343 #endif /* !__GENERIC_PER_CPU */
345 /* Called by boot processor to activate the rest. */
346 static void __init smp_init(void)
350 /* FIXME: This should be done in userspace --RR */
351 for_each_present_cpu(i) {
352 if (num_online_cpus() >= max_cpus)
358 /* Any cleanup work */
359 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
360 smp_cpus_done(max_cpus);
362 /* Get other processors into their bootup holding patterns. */
371 * We need to finalize in a non-__init function or else race conditions
372 * between the root thread and the init thread may cause start_kernel to
373 * be reaped by free_initmem before the root thread has proceeded to
376 * gcc-3.4 accidentally inlines this function, so use noinline.
379 static void noinline rest_init(void)
380 __releases(kernel_lock)
382 kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
383 numa_default_policy();
385 preempt_enable_no_resched();
389 /* Check for early params. */
390 static int __init do_early_param(char *param, char *val)
392 struct obs_kernel_param *p;
394 for (p = __setup_start; p < __setup_end; p++) {
395 if (p->early && strcmp(param, p->str) == 0) {
396 if (p->setup_func(val) != 0)
398 "Malformed early option '%s'\n", param);
401 /* We accept everything at this stage. */
405 /* Arch code calls this early on, or if not, just before other parsing. */
406 void __init parse_early_param(void)
408 static __initdata int done = 0;
409 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
414 /* All fall through to do_early_param. */
415 strlcpy(tmp_cmdline, saved_command_line, COMMAND_LINE_SIZE);
416 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
421 * Activate the first processor.
424 asmlinkage void __init start_kernel(void)
427 extern struct kernel_param __start___param[], __stop___param[];
429 * Interrupts are still disabled. Do necessary setups, then
435 printk(linux_banner);
436 setup_arch(&command_line);
437 setup_per_cpu_areas();
440 * Mark the boot cpu "online" so that it can call console drivers in
441 * printk() and can access its per-cpu storage.
443 smp_prepare_boot_cpu();
446 * Set up the scheduler prior starting any interrupts (such as the
447 * timer interrupt). Full topology setup happens at smp_init()
448 * time - but meanwhile we still have a functioning scheduler.
452 * Disable preemption - early bootup scheduling is extremely
453 * fragile until we cpu_idle() for the first time.
456 build_all_zonelists();
458 printk(KERN_NOTICE "Kernel command line: %s\n", saved_command_line);
460 parse_args("Booting kernel", command_line, __start___param,
461 __stop___param - __start___param,
462 &unknown_bootoption);
473 * HACK ALERT! This is early. We're enabling the console before
474 * we've done PCI setups etc, and console_init() must be aware of
475 * this. But we do want output early, in case something goes wrong.
479 panic(panic_later, panic_param);
482 #ifdef CONFIG_BLK_DEV_INITRD
483 if (initrd_start && !initrd_below_start_ok &&
484 initrd_start < min_low_pfn << PAGE_SHIFT) {
485 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
486 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
490 vfs_caches_init_early();
498 pgtable_cache_init();
503 efi_enter_virtual_mode();
505 fork_init(num_physpages);
511 vfs_caches_init(num_physpages);
514 /* rootfs populating might need page-writeback */
515 page_writeback_init();
516 #ifdef CONFIG_PROC_FS
523 acpi_early_init(); /* before LAPIC and SMP init */
525 /* Do the rest non-__init'ed, we're now alive */
529 static int __initdata initcall_debug;
531 static int __init initcall_debug_setup(char *str)
536 __setup("initcall_debug", initcall_debug_setup);
538 struct task_struct *child_reaper = &init_task;
540 extern initcall_t __initcall_start[], __initcall_end[];
542 static void __init do_initcalls(void)
545 int count = preempt_count();
547 for (call = __initcall_start; call < __initcall_end; call++) {
550 if (initcall_debug) {
551 printk(KERN_DEBUG "Calling initcall 0x%p", *call);
552 print_fn_descriptor_symbol(": %s()", (unsigned long) *call);
559 if (preempt_count() != count) {
560 msg = "preemption imbalance";
561 preempt_count() = count;
563 if (irqs_disabled()) {
564 msg = "disabled interrupts";
568 printk(KERN_WARNING "error in initcall at 0x%p: "
569 "returned with %s\n", *call, msg);
573 /* Make sure there is no pending stuff from the initcall sequence */
574 flush_scheduled_work();
578 * Ok, the machine is now initialized. None of the devices
579 * have been touched yet, but the CPU subsystem is up and
580 * running, and memory and process management works.
582 * Now we can finally start doing some real work..
584 static void __init do_basic_setup(void)
586 /* drivers will send hotplug events */
588 usermodehelper_init();
595 /* Networking initialization needs a process context */
601 static void do_pre_smp_initcalls(void)
603 extern int spawn_ksoftirqd(void);
605 extern int migration_init(void);
612 static void run_init_process(char *init_filename)
614 argv_init[0] = init_filename;
615 execve(init_filename, argv_init, envp_init);
618 static inline void fixup_cpu_present_map(void)
624 * If arch is not hotplug ready and did not populate
625 * cpu_present_map, just make cpu_present_map same as cpu_possible_map
626 * for other cpu bringup code to function as normal. e.g smp_init() etc.
628 if (cpus_empty(cpu_present_map)) {
630 cpu_set(i, cpu_present_map);
636 static int init(void * unused)
640 * init can run on any cpu.
642 set_cpus_allowed(current, CPU_MASK_ALL);
644 * Tell the world that we're going to be the grim
645 * reaper of innocent orphaned children.
647 * We don't want people to have to make incorrect
648 * assumptions about where in the task array this
651 child_reaper = current;
653 /* Sets up cpus_possible() */
654 smp_prepare_cpus(max_cpus);
656 do_pre_smp_initcalls();
658 fixup_cpu_present_map();
665 * Do this before initcalls, because some drivers want to access
673 * check if there is an early userspace init. If yes, let it do all
676 if (sys_access((const char __user *) "/init", 0) == 0)
677 execute_command = "/init";
682 * Ok, we have completed the initial bootup, and
683 * we're essentially up and running. Get rid of the
684 * initmem segments and start the user-mode stuff..
688 system_state = SYSTEM_RUNNING;
689 numa_default_policy();
691 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
692 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
698 * We try each of these until one succeeds.
700 * The Bourne shell can be used instead of init if we are
701 * trying to recover a really broken machine.
705 run_init_process(execute_command);
707 run_init_process("/sbin/init");
708 run_init_process("/etc/init");
709 run_init_process("/bin/init");
710 run_init_process("/bin/sh");
712 panic("No init found. Try passing init= option to kernel.");