ia64/linux-2.6.18-xen.hg

view init/main.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
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 */
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/taskstats_kern.h>
45 #include <linux/delayacct.h>
46 #include <linux/unistd.h>
47 #include <linux/rmap.h>
48 #include <linux/mempolicy.h>
49 #include <linux/key.h>
50 #include <linux/unwind.h>
51 #include <linux/buffer_head.h>
52 #include <linux/debug_locks.h>
53 #include <linux/lockdep.h>
55 #include <asm/io.h>
56 #include <asm/bugs.h>
57 #include <asm/setup.h>
58 #include <asm/sections.h>
59 #include <asm/cacheflush.h>
61 #ifdef CONFIG_X86_LOCAL_APIC
62 #include <asm/smp.h>
63 #endif
65 /*
66 * This is one of the first .c files built. Error out early if we have compiler
67 * trouble.
68 *
69 * Versions of gcc older than that listed below may actually compile and link
70 * okay, but the end product can have subtle run time bugs. To avoid associated
71 * bogus bug reports, we flatly refuse to compile with a gcc that is known to be
72 * too old from the very beginning.
73 */
74 #if (__GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 2)
75 #error Sorry, your GCC is too old. It builds incorrect kernels.
76 #endif
78 static int init(void *);
80 extern void init_IRQ(void);
81 extern void fork_init(unsigned long);
82 extern void mca_init(void);
83 extern void sbus_init(void);
84 extern void sysctl_init(void);
85 extern void signals_init(void);
86 extern void pidhash_init(void);
87 extern void pidmap_init(void);
88 extern void prio_tree_init(void);
89 extern void radix_tree_init(void);
90 extern void free_initmem(void);
91 extern void populate_rootfs(void);
92 extern void driver_init(void);
93 extern void prepare_namespace(void);
94 #ifdef CONFIG_ACPI
95 extern void acpi_early_init(void);
96 #else
97 static inline void acpi_early_init(void) { }
98 #endif
99 #ifndef CONFIG_DEBUG_RODATA
100 static inline void mark_rodata_ro(void) { }
101 #endif
103 #ifdef CONFIG_TC
104 extern void tc_init(void);
105 #endif
107 enum system_states system_state;
108 EXPORT_SYMBOL(system_state);
110 /*
111 * Boot command-line arguments
112 */
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;
125 static char *ramdisk_execute_command;
127 /* Setup configured maximum number of CPUs to activate */
128 static unsigned int max_cpus = NR_CPUS;
130 /*
131 * Setup routine for controlling SMP activation
132 *
133 * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
134 * activation entirely (the MPS table probe still happens, though).
135 *
136 * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
137 * greater than 0, limits the maximum number of CPUs activated in
138 * SMP mode to <NUM>.
139 */
140 static int __init nosmp(char *str)
141 {
142 max_cpus = 0;
143 return 1;
144 }
146 __setup("nosmp", nosmp);
148 static int __init maxcpus(char *str)
149 {
150 get_option(&str, &max_cpus);
151 return 1;
152 }
154 __setup("maxcpus=", maxcpus);
156 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
157 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
158 static const char *panic_later, *panic_param;
160 extern struct obs_kernel_param __setup_start[], __setup_end[];
162 static int __init obsolete_checksetup(char *line)
163 {
164 struct obs_kernel_param *p;
166 p = __setup_start;
167 do {
168 int n = strlen(p->str);
169 if (!strncmp(line, p->str, n)) {
170 if (p->early) {
171 /* Already done in parse_early_param? (Needs
172 * exact match on param part) */
173 if (line[n] == '\0' || line[n] == '=')
174 return 1;
175 } else if (!p->setup_func) {
176 printk(KERN_WARNING "Parameter %s is obsolete,"
177 " ignored\n", p->str);
178 return 1;
179 } else if (p->setup_func(line + n))
180 return 1;
181 }
182 p++;
183 } while (p < __setup_end);
184 return 0;
185 }
187 /*
188 * This should be approx 2 Bo*oMips to start (note initial shift), and will
189 * still work even if initially too large, it will just take slightly longer
190 */
191 unsigned long loops_per_jiffy = (1<<12);
193 EXPORT_SYMBOL(loops_per_jiffy);
195 static int __init debug_kernel(char *str)
196 {
197 if (*str)
198 return 0;
199 console_loglevel = 10;
200 return 1;
201 }
203 static int __init quiet_kernel(char *str)
204 {
205 if (*str)
206 return 0;
207 console_loglevel = 4;
208 return 1;
209 }
211 __setup("debug", debug_kernel);
212 __setup("quiet", quiet_kernel);
214 static int __init loglevel(char *str)
215 {
216 get_option(&str, &console_loglevel);
217 return 1;
218 }
220 __setup("loglevel=", loglevel);
222 /*
223 * Unknown boot options get handed to init, unless they look like
224 * failed parameters
225 */
226 static int __init unknown_bootoption(char *param, char *val)
227 {
228 /* Change NUL term back to "=", to make "param" the whole string. */
229 if (val) {
230 /* param=val or param="val"? */
231 if (val == param+strlen(param)+1)
232 val[-1] = '=';
233 else if (val == param+strlen(param)+2) {
234 val[-2] = '=';
235 memmove(val-1, val, strlen(val)+1);
236 val--;
237 } else
238 BUG();
239 }
241 /* Handle obsolete-style parameters */
242 if (obsolete_checksetup(param))
243 return 0;
245 /*
246 * Preemptive maintenance for "why didn't my mispelled command
247 * line work?"
248 */
249 if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
250 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
251 return 0;
252 }
254 if (panic_later)
255 return 0;
257 if (val) {
258 /* Environment option */
259 unsigned int i;
260 for (i = 0; envp_init[i]; i++) {
261 if (i == MAX_INIT_ENVS) {
262 panic_later = "Too many boot env vars at `%s'";
263 panic_param = param;
264 }
265 if (!strncmp(param, envp_init[i], val - param))
266 break;
267 }
268 envp_init[i] = param;
269 } else {
270 /* Command line option */
271 unsigned int i;
272 for (i = 0; argv_init[i]; i++) {
273 if (i == MAX_INIT_ARGS) {
274 panic_later = "Too many boot init vars at `%s'";
275 panic_param = param;
276 }
277 }
278 argv_init[i] = param;
279 }
280 return 0;
281 }
283 static int __init init_setup(char *str)
284 {
285 unsigned int i;
287 execute_command = str;
288 /*
289 * In case LILO is going to boot us with default command line,
290 * it prepends "auto" before the whole cmdline which makes
291 * the shell think it should execute a script with such name.
292 * So we ignore all arguments entered _before_ init=... [MJ]
293 */
294 for (i = 1; i < MAX_INIT_ARGS; i++)
295 argv_init[i] = NULL;
296 return 1;
297 }
298 __setup("init=", init_setup);
300 static int __init rdinit_setup(char *str)
301 {
302 unsigned int i;
304 ramdisk_execute_command = str;
305 /* See "auto" comment in init_setup */
306 for (i = 1; i < MAX_INIT_ARGS; i++)
307 argv_init[i] = NULL;
308 return 1;
309 }
310 __setup("rdinit=", rdinit_setup);
312 #ifndef CONFIG_SMP
314 #ifdef CONFIG_X86_LOCAL_APIC
315 static void __init smp_init(void)
316 {
317 APIC_init_uniprocessor();
318 }
319 #else
320 #define smp_init() do { } while (0)
321 #endif
323 static inline void setup_per_cpu_areas(void) { }
324 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
326 #else
328 #ifdef __GENERIC_PER_CPU
329 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
331 EXPORT_SYMBOL(__per_cpu_offset);
333 static void __init setup_per_cpu_areas(void)
334 {
335 unsigned long size, i;
336 char *ptr;
337 unsigned long nr_possible_cpus = num_possible_cpus();
339 /* Copy section for each CPU (we discard the original) */
340 size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
341 #ifdef CONFIG_MODULES
342 if (size < PERCPU_ENOUGH_ROOM)
343 size = PERCPU_ENOUGH_ROOM;
344 #endif
345 ptr = alloc_bootmem(size * nr_possible_cpus);
347 for_each_possible_cpu(i) {
348 __per_cpu_offset[i] = ptr - __per_cpu_start;
349 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
350 ptr += size;
351 }
352 }
353 #endif /* !__GENERIC_PER_CPU */
355 /* Called by boot processor to activate the rest. */
356 static void __init smp_init(void)
357 {
358 unsigned int i;
360 /* FIXME: This should be done in userspace --RR */
361 for_each_present_cpu(i) {
362 if (num_online_cpus() >= max_cpus)
363 break;
364 if (!cpu_online(i))
365 cpu_up(i);
366 }
368 /* Any cleanup work */
369 printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
370 smp_cpus_done(max_cpus);
371 #if 0
372 /* Get other processors into their bootup holding patterns. */
374 smp_commence();
375 #endif
376 }
378 #endif
380 /*
381 * We need to finalize in a non-__init function or else race conditions
382 * between the root thread and the init thread may cause start_kernel to
383 * be reaped by free_initmem before the root thread has proceeded to
384 * cpu_idle.
385 *
386 * gcc-3.4 accidentally inlines this function, so use noinline.
387 */
389 static void noinline rest_init(void)
390 __releases(kernel_lock)
391 {
392 kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
393 numa_default_policy();
394 unlock_kernel();
396 /*
397 * The boot idle thread must execute schedule()
398 * at least one to get things moving:
399 */
400 preempt_enable_no_resched();
401 schedule();
402 preempt_disable();
404 /* Call into cpu_idle with preempt disabled */
405 cpu_idle();
406 }
408 /* Check for early params. */
409 static int __init do_early_param(char *param, char *val)
410 {
411 struct obs_kernel_param *p;
413 for (p = __setup_start; p < __setup_end; p++) {
414 if (p->early && strcmp(param, p->str) == 0) {
415 if (p->setup_func(val) != 0)
416 printk(KERN_WARNING
417 "Malformed early option '%s'\n", param);
418 }
419 }
420 /* We accept everything at this stage. */
421 return 0;
422 }
424 /* Arch code calls this early on, or if not, just before other parsing. */
425 void __init parse_early_param(void)
426 {
427 static __initdata int done = 0;
428 static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
430 if (done)
431 return;
433 /* All fall through to do_early_param. */
434 strlcpy(tmp_cmdline, saved_command_line, COMMAND_LINE_SIZE);
435 parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
436 done = 1;
437 }
439 /*
440 * Activate the first processor.
441 */
443 static void __init boot_cpu_init(void)
444 {
445 int cpu = smp_processor_id();
446 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
447 cpu_set(cpu, cpu_online_map);
448 cpu_set(cpu, cpu_present_map);
449 cpu_set(cpu, cpu_possible_map);
450 }
452 void __init __attribute__((weak)) smp_setup_processor_id(void)
453 {
454 }
456 asmlinkage void __init start_kernel(void)
457 {
458 char * command_line;
459 extern struct kernel_param __start___param[], __stop___param[];
461 smp_setup_processor_id();
463 /*
464 * Need to run as early as possible, to initialize the
465 * lockdep hash:
466 */
467 lockdep_init();
469 local_irq_disable();
470 early_boot_irqs_off();
471 early_init_irq_lock_class();
473 /*
474 * Interrupts are still disabled. Do necessary setups, then
475 * enable them
476 */
477 lock_kernel();
478 boot_cpu_init();
479 page_address_init();
480 printk(KERN_NOTICE);
481 printk(linux_banner);
482 setup_arch(&command_line);
483 setup_per_cpu_areas();
484 smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
486 /*
487 * Set up the scheduler prior starting any interrupts (such as the
488 * timer interrupt). Full topology setup happens at smp_init()
489 * time - but meanwhile we still have a functioning scheduler.
490 */
491 sched_init();
492 /*
493 * Disable preemption - early bootup scheduling is extremely
494 * fragile until we cpu_idle() for the first time.
495 */
496 preempt_disable();
497 build_all_zonelists();
498 page_alloc_init();
499 printk(KERN_NOTICE "Kernel command line: %s\n", saved_command_line);
500 parse_early_param();
501 parse_args("Booting kernel", command_line, __start___param,
502 __stop___param - __start___param,
503 &unknown_bootoption);
504 sort_main_extable();
505 unwind_init();
506 trap_init();
507 rcu_init();
508 init_IRQ();
509 pidhash_init();
510 init_timers();
511 hrtimers_init();
512 softirq_init();
513 timekeeping_init();
514 time_init();
515 profile_init();
516 if (!irqs_disabled())
517 printk("start_kernel(): bug: interrupts were enabled early\n");
518 early_boot_irqs_on();
519 local_irq_enable();
521 /*
522 * HACK ALERT! This is early. We're enabling the console before
523 * we've done PCI setups etc, and console_init() must be aware of
524 * this. But we do want output early, in case something goes wrong.
525 */
526 console_init();
527 if (panic_later)
528 panic(panic_later, panic_param);
530 lockdep_info();
532 /*
533 * Need to run this when irqs are enabled, because it wants
534 * to self-test [hard/soft]-irqs on/off lock inversion bugs
535 * too:
536 */
537 locking_selftest();
539 #ifdef CONFIG_BLK_DEV_INITRD
540 if (initrd_start && !initrd_below_start_ok &&
541 initrd_start < min_low_pfn << PAGE_SHIFT) {
542 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
543 "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
544 initrd_start = 0;
545 }
546 #endif
547 vfs_caches_init_early();
548 cpuset_init_early();
549 mem_init();
550 kmem_cache_init();
551 setup_per_cpu_pageset();
552 numa_policy_init();
553 if (late_time_init)
554 late_time_init();
555 calibrate_delay();
556 pidmap_init();
557 pgtable_cache_init();
558 prio_tree_init();
559 anon_vma_init();
560 #ifdef CONFIG_X86
561 if (efi_enabled)
562 efi_enter_virtual_mode();
563 #endif
564 fork_init(num_physpages);
565 proc_caches_init();
566 buffer_init();
567 unnamed_dev_init();
568 key_init();
569 security_init();
570 vfs_caches_init(num_physpages);
571 radix_tree_init();
572 signals_init();
573 /* rootfs populating might need page-writeback */
574 page_writeback_init();
575 #ifdef CONFIG_PROC_FS
576 proc_root_init();
577 #endif
578 cpuset_init();
579 taskstats_init_early();
580 delayacct_init();
582 check_bugs();
584 acpi_early_init(); /* before LAPIC and SMP init */
586 /* Do the rest non-__init'ed, we're now alive */
587 rest_init();
588 }
590 static int __initdata initcall_debug;
592 static int __init initcall_debug_setup(char *str)
593 {
594 initcall_debug = 1;
595 return 1;
596 }
597 __setup("initcall_debug", initcall_debug_setup);
599 struct task_struct *child_reaper = &init_task;
601 extern initcall_t __initcall_start[], __initcall_end[];
603 static void __init do_initcalls(void)
604 {
605 initcall_t *call;
606 int count = preempt_count();
608 for (call = __initcall_start; call < __initcall_end; call++) {
609 char *msg = NULL;
610 char msgbuf[40];
611 int result;
613 if (initcall_debug) {
614 printk("Calling initcall 0x%p", *call);
615 print_fn_descriptor_symbol(": %s()",
616 (unsigned long) *call);
617 printk("\n");
618 }
620 result = (*call)();
622 if (result && result != -ENODEV && initcall_debug) {
623 sprintf(msgbuf, "error code %d", result);
624 msg = msgbuf;
625 }
626 if (preempt_count() != count) {
627 msg = "preemption imbalance";
628 preempt_count() = count;
629 }
630 if (irqs_disabled()) {
631 msg = "disabled interrupts";
632 local_irq_enable();
633 }
634 if (msg) {
635 printk(KERN_WARNING "initcall at 0x%p", *call);
636 print_fn_descriptor_symbol(": %s()",
637 (unsigned long) *call);
638 printk(": returned with %s\n", msg);
639 }
640 }
642 /* Make sure there is no pending stuff from the initcall sequence */
643 flush_scheduled_work();
644 }
646 /*
647 * Ok, the machine is now initialized. None of the devices
648 * have been touched yet, but the CPU subsystem is up and
649 * running, and memory and process management works.
650 *
651 * Now we can finally start doing some real work..
652 */
653 static void __init do_basic_setup(void)
654 {
655 /* drivers will send hotplug events */
656 init_workqueues();
657 usermodehelper_init();
658 driver_init();
660 #ifdef CONFIG_SYSCTL
661 sysctl_init();
662 #endif
664 do_initcalls();
665 }
667 static void do_pre_smp_initcalls(void)
668 {
669 extern int spawn_ksoftirqd(void);
670 #ifdef CONFIG_SMP
671 extern int migration_init(void);
673 migration_init();
674 #endif
675 spawn_ksoftirqd();
676 spawn_softlockup_task();
677 }
679 static void run_init_process(char *init_filename)
680 {
681 argv_init[0] = init_filename;
682 execve(init_filename, argv_init, envp_init);
683 }
685 static int init(void * unused)
686 {
687 lock_kernel();
688 /*
689 * init can run on any cpu.
690 */
691 set_cpus_allowed(current, CPU_MASK_ALL);
692 /*
693 * Tell the world that we're going to be the grim
694 * reaper of innocent orphaned children.
695 *
696 * We don't want people to have to make incorrect
697 * assumptions about where in the task array this
698 * can be found.
699 */
700 child_reaper = current;
702 smp_prepare_cpus(max_cpus);
704 do_pre_smp_initcalls();
706 smp_init();
707 sched_init_smp();
709 cpuset_init_smp();
711 /*
712 * Do this before initcalls, because some drivers want to access
713 * firmware files.
714 */
715 populate_rootfs();
717 do_basic_setup();
719 /*
720 * check if there is an early userspace init. If yes, let it do all
721 * the work
722 */
724 if (!ramdisk_execute_command)
725 ramdisk_execute_command = "/init";
727 if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
728 ramdisk_execute_command = NULL;
729 prepare_namespace();
730 }
732 /*
733 * Ok, we have completed the initial bootup, and
734 * we're essentially up and running. Get rid of the
735 * initmem segments and start the user-mode stuff..
736 */
737 free_initmem();
738 unlock_kernel();
739 mark_rodata_ro();
740 system_state = SYSTEM_RUNNING;
741 numa_default_policy();
743 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
744 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
746 (void) sys_dup(0);
747 (void) sys_dup(0);
749 if (ramdisk_execute_command) {
750 run_init_process(ramdisk_execute_command);
751 printk(KERN_WARNING "Failed to execute %s\n",
752 ramdisk_execute_command);
753 }
755 /*
756 * We try each of these until one succeeds.
757 *
758 * The Bourne shell can be used instead of init if we are
759 * trying to recover a really broken machine.
760 */
761 if (execute_command) {
762 run_init_process(execute_command);
763 printk(KERN_WARNING "Failed to execute %s. Attempting "
764 "defaults...\n", execute_command);
765 }
766 run_init_process("/sbin/init");
767 run_init_process("/etc/init");
768 run_init_process("/bin/init");
769 run_init_process("/bin/sh");
771 panic("No init found. Try passing init= option to kernel.");
772 }