Version:  2.0.40 2.2.26 2.4.37 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1

Linux/init/main.c

  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 DEBUG           /* Enable initcall_debug */
 13 
 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/stackprotector.h>
 20 #include <linux/string.h>
 21 #include <linux/ctype.h>
 22 #include <linux/delay.h>
 23 #include <linux/ioport.h>
 24 #include <linux/init.h>
 25 #include <linux/initrd.h>
 26 #include <linux/bootmem.h>
 27 #include <linux/acpi.h>
 28 #include <linux/tty.h>
 29 #include <linux/percpu.h>
 30 #include <linux/kmod.h>
 31 #include <linux/vmalloc.h>
 32 #include <linux/kernel_stat.h>
 33 #include <linux/start_kernel.h>
 34 #include <linux/security.h>
 35 #include <linux/smp.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/cgroup.h>
 44 #include <linux/efi.h>
 45 #include <linux/tick.h>
 46 #include <linux/interrupt.h>
 47 #include <linux/taskstats_kern.h>
 48 #include <linux/delayacct.h>
 49 #include <linux/unistd.h>
 50 #include <linux/rmap.h>
 51 #include <linux/mempolicy.h>
 52 #include <linux/key.h>
 53 #include <linux/buffer_head.h>
 54 #include <linux/page_ext.h>
 55 #include <linux/debug_locks.h>
 56 #include <linux/debugobjects.h>
 57 #include <linux/lockdep.h>
 58 #include <linux/kmemleak.h>
 59 #include <linux/pid_namespace.h>
 60 #include <linux/device.h>
 61 #include <linux/kthread.h>
 62 #include <linux/sched.h>
 63 #include <linux/signal.h>
 64 #include <linux/idr.h>
 65 #include <linux/kgdb.h>
 66 #include <linux/ftrace.h>
 67 #include <linux/async.h>
 68 #include <linux/kmemcheck.h>
 69 #include <linux/sfi.h>
 70 #include <linux/shmem_fs.h>
 71 #include <linux/slab.h>
 72 #include <linux/perf_event.h>
 73 #include <linux/file.h>
 74 #include <linux/ptrace.h>
 75 #include <linux/blkdev.h>
 76 #include <linux/elevator.h>
 77 #include <linux/sched_clock.h>
 78 #include <linux/context_tracking.h>
 79 #include <linux/random.h>
 80 #include <linux/list.h>
 81 #include <linux/integrity.h>
 82 #include <linux/proc_ns.h>
 83 #include <linux/io.h>
 84 
 85 #include <asm/io.h>
 86 #include <asm/bugs.h>
 87 #include <asm/setup.h>
 88 #include <asm/sections.h>
 89 #include <asm/cacheflush.h>
 90 
 91 static int kernel_init(void *);
 92 
 93 extern void init_IRQ(void);
 94 extern void fork_init(void);
 95 extern void radix_tree_init(void);
 96 #ifndef CONFIG_DEBUG_RODATA
 97 static inline void mark_rodata_ro(void) { }
 98 #endif
 99 
100 /*
101  * Debug helper: via this flag we know that we are in 'early bootup code'
102  * where only the boot processor is running with IRQ disabled.  This means
103  * two things - IRQ must not be enabled before the flag is cleared and some
104  * operations which are not allowed with IRQ disabled are allowed while the
105  * flag is set.
106  */
107 bool early_boot_irqs_disabled __read_mostly;
108 
109 enum system_states system_state __read_mostly;
110 EXPORT_SYMBOL(system_state);
111 
112 /*
113  * Boot command-line arguments
114  */
115 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
116 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
117 
118 extern void time_init(void);
119 /* Default late time init is NULL. archs can override this later. */
120 void (*__initdata late_time_init)(void);
121 
122 /* Untouched command line saved by arch-specific code. */
123 char __initdata boot_command_line[COMMAND_LINE_SIZE];
124 /* Untouched saved command line (eg. for /proc) */
125 char *saved_command_line;
126 /* Command line for parameter parsing */
127 static char *static_command_line;
128 /* Command line for per-initcall parameter parsing */
129 static char *initcall_command_line;
130 
131 static char *execute_command;
132 static char *ramdisk_execute_command;
133 
134 /*
135  * Used to generate warnings if static_key manipulation functions are used
136  * before jump_label_init is called.
137  */
138 bool static_key_initialized __read_mostly;
139 EXPORT_SYMBOL_GPL(static_key_initialized);
140 
141 /*
142  * If set, this is an indication to the drivers that reset the underlying
143  * device before going ahead with the initialization otherwise driver might
144  * rely on the BIOS and skip the reset operation.
145  *
146  * This is useful if kernel is booting in an unreliable environment.
147  * For ex. kdump situation where previous kernel has crashed, BIOS has been
148  * skipped and devices will be in unknown state.
149  */
150 unsigned int reset_devices;
151 EXPORT_SYMBOL(reset_devices);
152 
153 static int __init set_reset_devices(char *str)
154 {
155         reset_devices = 1;
156         return 1;
157 }
158 
159 __setup("reset_devices", set_reset_devices);
160 
161 static const char *argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
162 const char *envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
163 static const char *panic_later, *panic_param;
164 
165 extern const struct obs_kernel_param __setup_start[], __setup_end[];
166 
167 static int __init obsolete_checksetup(char *line)
168 {
169         const struct obs_kernel_param *p;
170         int had_early_param = 0;
171 
172         p = __setup_start;
173         do {
174                 int n = strlen(p->str);
175                 if (parameqn(line, p->str, n)) {
176                         if (p->early) {
177                                 /* Already done in parse_early_param?
178                                  * (Needs exact match on param part).
179                                  * Keep iterating, as we can have early
180                                  * params and __setups of same names 8( */
181                                 if (line[n] == '\0' || line[n] == '=')
182                                         had_early_param = 1;
183                         } else if (!p->setup_func) {
184                                 pr_warn("Parameter %s is obsolete, ignored\n",
185                                         p->str);
186                                 return 1;
187                         } else if (p->setup_func(line + n))
188                                 return 1;
189                 }
190                 p++;
191         } while (p < __setup_end);
192 
193         return had_early_param;
194 }
195 
196 /*
197  * This should be approx 2 Bo*oMips to start (note initial shift), and will
198  * still work even if initially too large, it will just take slightly longer
199  */
200 unsigned long loops_per_jiffy = (1<<12);
201 EXPORT_SYMBOL(loops_per_jiffy);
202 
203 static int __init debug_kernel(char *str)
204 {
205         console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
206         return 0;
207 }
208 
209 static int __init quiet_kernel(char *str)
210 {
211         console_loglevel = CONSOLE_LOGLEVEL_QUIET;
212         return 0;
213 }
214 
215 early_param("debug", debug_kernel);
216 early_param("quiet", quiet_kernel);
217 
218 static int __init loglevel(char *str)
219 {
220         int newlevel;
221 
222         /*
223          * Only update loglevel value when a correct setting was passed,
224          * to prevent blind crashes (when loglevel being set to 0) that
225          * are quite hard to debug
226          */
227         if (get_option(&str, &newlevel)) {
228                 console_loglevel = newlevel;
229                 return 0;
230         }
231 
232         return -EINVAL;
233 }
234 
235 early_param("loglevel", loglevel);
236 
237 /* Change NUL term back to "=", to make "param" the whole string. */
238 static int __init repair_env_string(char *param, char *val, const char *unused)
239 {
240         if (val) {
241                 /* param=val or param="val"? */
242                 if (val == param+strlen(param)+1)
243                         val[-1] = '=';
244                 else if (val == param+strlen(param)+2) {
245                         val[-2] = '=';
246                         memmove(val-1, val, strlen(val)+1);
247                         val--;
248                 } else
249                         BUG();
250         }
251         return 0;
252 }
253 
254 /* Anything after -- gets handed straight to init. */
255 static int __init set_init_arg(char *param, char *val, const char *unused)
256 {
257         unsigned int i;
258 
259         if (panic_later)
260                 return 0;
261 
262         repair_env_string(param, val, unused);
263 
264         for (i = 0; argv_init[i]; i++) {
265                 if (i == MAX_INIT_ARGS) {
266                         panic_later = "init";
267                         panic_param = param;
268                         return 0;
269                 }
270         }
271         argv_init[i] = param;
272         return 0;
273 }
274 
275 /*
276  * Unknown boot options get handed to init, unless they look like
277  * unused parameters (modprobe will find them in /proc/cmdline).
278  */
279 static int __init unknown_bootoption(char *param, char *val, const char *unused)
280 {
281         repair_env_string(param, val, unused);
282 
283         /* Handle obsolete-style parameters */
284         if (obsolete_checksetup(param))
285                 return 0;
286 
287         /* Unused module parameter. */
288         if (strchr(param, '.') && (!val || strchr(param, '.') < val))
289                 return 0;
290 
291         if (panic_later)
292                 return 0;
293 
294         if (val) {
295                 /* Environment option */
296                 unsigned int i;
297                 for (i = 0; envp_init[i]; i++) {
298                         if (i == MAX_INIT_ENVS) {
299                                 panic_later = "env";
300                                 panic_param = param;
301                         }
302                         if (!strncmp(param, envp_init[i], val - param))
303                                 break;
304                 }
305                 envp_init[i] = param;
306         } else {
307                 /* Command line option */
308                 unsigned int i;
309                 for (i = 0; argv_init[i]; i++) {
310                         if (i == MAX_INIT_ARGS) {
311                                 panic_later = "init";
312                                 panic_param = param;
313                         }
314                 }
315                 argv_init[i] = param;
316         }
317         return 0;
318 }
319 
320 static int __init init_setup(char *str)
321 {
322         unsigned int i;
323 
324         execute_command = str;
325         /*
326          * In case LILO is going to boot us with default command line,
327          * it prepends "auto" before the whole cmdline which makes
328          * the shell think it should execute a script with such name.
329          * So we ignore all arguments entered _before_ init=... [MJ]
330          */
331         for (i = 1; i < MAX_INIT_ARGS; i++)
332                 argv_init[i] = NULL;
333         return 1;
334 }
335 __setup("init=", init_setup);
336 
337 static int __init rdinit_setup(char *str)
338 {
339         unsigned int i;
340 
341         ramdisk_execute_command = str;
342         /* See "auto" comment in init_setup */
343         for (i = 1; i < MAX_INIT_ARGS; i++)
344                 argv_init[i] = NULL;
345         return 1;
346 }
347 __setup("rdinit=", rdinit_setup);
348 
349 #ifndef CONFIG_SMP
350 static const unsigned int setup_max_cpus = NR_CPUS;
351 static inline void setup_nr_cpu_ids(void) { }
352 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
353 #endif
354 
355 /*
356  * We need to store the untouched command line for future reference.
357  * We also need to store the touched command line since the parameter
358  * parsing is performed in place, and we should allow a component to
359  * store reference of name/value for future reference.
360  */
361 static void __init setup_command_line(char *command_line)
362 {
363         saved_command_line =
364                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
365         initcall_command_line =
366                 memblock_virt_alloc(strlen(boot_command_line) + 1, 0);
367         static_command_line = memblock_virt_alloc(strlen(command_line) + 1, 0);
368         strcpy(saved_command_line, boot_command_line);
369         strcpy(static_command_line, command_line);
370 }
371 
372 /*
373  * We need to finalize in a non-__init function or else race conditions
374  * between the root thread and the init thread may cause start_kernel to
375  * be reaped by free_initmem before the root thread has proceeded to
376  * cpu_idle.
377  *
378  * gcc-3.4 accidentally inlines this function, so use noinline.
379  */
380 
381 static __initdata DECLARE_COMPLETION(kthreadd_done);
382 
383 static noinline void __init_refok rest_init(void)
384 {
385         int pid;
386 
387         rcu_scheduler_starting();
388         smpboot_thread_init();
389         /*
390          * We need to spawn init first so that it obtains pid 1, however
391          * the init task will end up wanting to create kthreads, which, if
392          * we schedule it before we create kthreadd, will OOPS.
393          */
394         kernel_thread(kernel_init, NULL, CLONE_FS);
395         numa_default_policy();
396         pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
397         rcu_read_lock();
398         kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
399         rcu_read_unlock();
400         complete(&kthreadd_done);
401 
402         /*
403          * The boot idle thread must execute schedule()
404          * at least once to get things moving:
405          */
406         init_idle_bootup_task(current);
407         schedule_preempt_disabled();
408         /* Call into cpu_idle with preempt disabled */
409         cpu_startup_entry(CPUHP_ONLINE);
410 }
411 
412 /* Check for early params. */
413 static int __init do_early_param(char *param, char *val, const char *unused)
414 {
415         const struct obs_kernel_param *p;
416 
417         for (p = __setup_start; p < __setup_end; p++) {
418                 if ((p->early && parameq(param, p->str)) ||
419                     (strcmp(param, "console") == 0 &&
420                      strcmp(p->str, "earlycon") == 0)
421                 ) {
422                         if (p->setup_func(val) != 0)
423                                 pr_warn("Malformed early option '%s'\n", param);
424                 }
425         }
426         /* We accept everything at this stage. */
427         return 0;
428 }
429 
430 void __init parse_early_options(char *cmdline)
431 {
432         parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
433 }
434 
435 /* Arch code calls this early on, or if not, just before other parsing. */
436 void __init parse_early_param(void)
437 {
438         static int done __initdata;
439         static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
440 
441         if (done)
442                 return;
443 
444         /* All fall through to do_early_param. */
445         strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
446         parse_early_options(tmp_cmdline);
447         done = 1;
448 }
449 
450 /*
451  *      Activate the first processor.
452  */
453 
454 static void __init boot_cpu_init(void)
455 {
456         int cpu = smp_processor_id();
457         /* Mark the boot cpu "present", "online" etc for SMP and UP case */
458         set_cpu_online(cpu, true);
459         set_cpu_active(cpu, true);
460         set_cpu_present(cpu, true);
461         set_cpu_possible(cpu, true);
462 }
463 
464 void __init __weak smp_setup_processor_id(void)
465 {
466 }
467 
468 # if THREAD_SIZE >= PAGE_SIZE
469 void __init __weak thread_info_cache_init(void)
470 {
471 }
472 #endif
473 
474 /*
475  * Set up kernel memory allocators
476  */
477 static void __init mm_init(void)
478 {
479         /*
480          * page_ext requires contiguous pages,
481          * bigger than MAX_ORDER unless SPARSEMEM.
482          */
483         page_ext_init_flatmem();
484         mem_init();
485         kmem_cache_init();
486         percpu_init_late();
487         pgtable_init();
488         vmalloc_init();
489         ioremap_huge_init();
490 }
491 
492 asmlinkage __visible void __init start_kernel(void)
493 {
494         char *command_line;
495         char *after_dashes;
496 
497         /*
498          * Need to run as early as possible, to initialize the
499          * lockdep hash:
500          */
501         lockdep_init();
502         set_task_stack_end_magic(&init_task);
503         smp_setup_processor_id();
504         debug_objects_early_init();
505 
506         /*
507          * Set up the the initial canary ASAP:
508          */
509         boot_init_stack_canary();
510 
511         cgroup_init_early();
512 
513         local_irq_disable();
514         early_boot_irqs_disabled = true;
515 
516 /*
517  * Interrupts are still disabled. Do necessary setups, then
518  * enable them
519  */
520         boot_cpu_init();
521         page_address_init();
522         pr_notice("%s", linux_banner);
523         setup_arch(&command_line);
524         mm_init_cpumask(&init_mm);
525         setup_command_line(command_line);
526         setup_nr_cpu_ids();
527         setup_per_cpu_areas();
528         smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
529 
530         build_all_zonelists(NULL, NULL);
531         page_alloc_init();
532 
533         pr_notice("Kernel command line: %s\n", boot_command_line);
534         parse_early_param();
535         after_dashes = parse_args("Booting kernel",
536                                   static_command_line, __start___param,
537                                   __stop___param - __start___param,
538                                   -1, -1, &unknown_bootoption);
539         if (!IS_ERR_OR_NULL(after_dashes))
540                 parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,
541                            set_init_arg);
542 
543         jump_label_init();
544 
545         /*
546          * These use large bootmem allocations and must precede
547          * kmem_cache_init()
548          */
549         setup_log_buf(0);
550         pidhash_init();
551         vfs_caches_init_early();
552         sort_main_extable();
553         trap_init();
554         mm_init();
555 
556         /*
557          * Set up the scheduler prior starting any interrupts (such as the
558          * timer interrupt). Full topology setup happens at smp_init()
559          * time - but meanwhile we still have a functioning scheduler.
560          */
561         sched_init();
562         /*
563          * Disable preemption - early bootup scheduling is extremely
564          * fragile until we cpu_idle() for the first time.
565          */
566         preempt_disable();
567         if (WARN(!irqs_disabled(),
568                  "Interrupts were enabled *very* early, fixing it\n"))
569                 local_irq_disable();
570         idr_init_cache();
571         rcu_init();
572 
573         /* trace_printk() and trace points may be used after this */
574         trace_init();
575 
576         context_tracking_init();
577         radix_tree_init();
578         /* init some links before init_ISA_irqs() */
579         early_irq_init();
580         init_IRQ();
581         tick_init();
582         rcu_init_nohz();
583         init_timers();
584         hrtimers_init();
585         softirq_init();
586         timekeeping_init();
587         time_init();
588         sched_clock_postinit();
589         perf_event_init();
590         profile_init();
591         call_function_init();
592         WARN(!irqs_disabled(), "Interrupts were enabled early\n");
593         early_boot_irqs_disabled = false;
594         local_irq_enable();
595 
596         kmem_cache_init_late();
597 
598         /*
599          * HACK ALERT! This is early. We're enabling the console before
600          * we've done PCI setups etc, and console_init() must be aware of
601          * this. But we do want output early, in case something goes wrong.
602          */
603         console_init();
604         if (panic_later)
605                 panic("Too many boot %s vars at `%s'", panic_later,
606                       panic_param);
607 
608         lockdep_info();
609 
610         /*
611          * Need to run this when irqs are enabled, because it wants
612          * to self-test [hard/soft]-irqs on/off lock inversion bugs
613          * too:
614          */
615         locking_selftest();
616 
617 #ifdef CONFIG_BLK_DEV_INITRD
618         if (initrd_start && !initrd_below_start_ok &&
619             page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
620                 pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
621                     page_to_pfn(virt_to_page((void *)initrd_start)),
622                     min_low_pfn);
623                 initrd_start = 0;
624         }
625 #endif
626         page_ext_init();
627         debug_objects_mem_init();
628         kmemleak_init();
629         setup_per_cpu_pageset();
630         numa_policy_init();
631         if (late_time_init)
632                 late_time_init();
633         sched_clock_init();
634         calibrate_delay();
635         pidmap_init();
636         anon_vma_init();
637         acpi_early_init();
638 #ifdef CONFIG_X86
639         if (efi_enabled(EFI_RUNTIME_SERVICES))
640                 efi_enter_virtual_mode();
641 #endif
642 #ifdef CONFIG_X86_ESPFIX64
643         /* Should be run before the first non-init thread is created */
644         init_espfix_bsp();
645 #endif
646         thread_info_cache_init();
647         cred_init();
648         fork_init();
649         proc_caches_init();
650         buffer_init();
651         key_init();
652         security_init();
653         dbg_late_init();
654         vfs_caches_init(totalram_pages);
655         signals_init();
656         /* rootfs populating might need page-writeback */
657         page_writeback_init();
658         proc_root_init();
659         nsfs_init();
660         cpuset_init();
661         cgroup_init();
662         taskstats_init_early();
663         delayacct_init();
664 
665         check_bugs();
666 
667         sfi_init_late();
668 
669         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
670                 efi_late_init();
671                 efi_free_boot_services();
672         }
673 
674         ftrace_init();
675 
676         /* Do the rest non-__init'ed, we're now alive */
677         rest_init();
678 }
679 
680 /* Call all constructor functions linked into the kernel. */
681 static void __init do_ctors(void)
682 {
683 #ifdef CONFIG_CONSTRUCTORS
684         ctor_fn_t *fn = (ctor_fn_t *) __ctors_start;
685 
686         for (; fn < (ctor_fn_t *) __ctors_end; fn++)
687                 (*fn)();
688 #endif
689 }
690 
691 bool initcall_debug;
692 core_param(initcall_debug, initcall_debug, bool, 0644);
693 
694 #ifdef CONFIG_KALLSYMS
695 struct blacklist_entry {
696         struct list_head next;
697         char *buf;
698 };
699 
700 static __initdata_or_module LIST_HEAD(blacklisted_initcalls);
701 
702 static int __init initcall_blacklist(char *str)
703 {
704         char *str_entry;
705         struct blacklist_entry *entry;
706 
707         /* str argument is a comma-separated list of functions */
708         do {
709                 str_entry = strsep(&str, ",");
710                 if (str_entry) {
711                         pr_debug("blacklisting initcall %s\n", str_entry);
712                         entry = alloc_bootmem(sizeof(*entry));
713                         entry->buf = alloc_bootmem(strlen(str_entry) + 1);
714                         strcpy(entry->buf, str_entry);
715                         list_add(&entry->next, &blacklisted_initcalls);
716                 }
717         } while (str_entry);
718 
719         return 0;
720 }
721 
722 static bool __init_or_module initcall_blacklisted(initcall_t fn)
723 {
724         struct list_head *tmp;
725         struct blacklist_entry *entry;
726         char *fn_name;
727 
728         fn_name = kasprintf(GFP_KERNEL, "%pf", fn);
729         if (!fn_name)
730                 return false;
731 
732         list_for_each(tmp, &blacklisted_initcalls) {
733                 entry = list_entry(tmp, struct blacklist_entry, next);
734                 if (!strcmp(fn_name, entry->buf)) {
735                         pr_debug("initcall %s blacklisted\n", fn_name);
736                         kfree(fn_name);
737                         return true;
738                 }
739         }
740 
741         kfree(fn_name);
742         return false;
743 }
744 #else
745 static int __init initcall_blacklist(char *str)
746 {
747         pr_warn("initcall_blacklist requires CONFIG_KALLSYMS\n");
748         return 0;
749 }
750 
751 static bool __init_or_module initcall_blacklisted(initcall_t fn)
752 {
753         return false;
754 }
755 #endif
756 __setup("initcall_blacklist=", initcall_blacklist);
757 
758 static int __init_or_module do_one_initcall_debug(initcall_t fn)
759 {
760         ktime_t calltime, delta, rettime;
761         unsigned long long duration;
762         int ret;
763 
764         printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
765         calltime = ktime_get();
766         ret = fn();
767         rettime = ktime_get();
768         delta = ktime_sub(rettime, calltime);
769         duration = (unsigned long long) ktime_to_ns(delta) >> 10;
770         printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
771                  fn, ret, duration);
772 
773         return ret;
774 }
775 
776 int __init_or_module do_one_initcall(initcall_t fn)
777 {
778         int count = preempt_count();
779         int ret;
780         char msgbuf[64];
781 
782         if (initcall_blacklisted(fn))
783                 return -EPERM;
784 
785         if (initcall_debug)
786                 ret = do_one_initcall_debug(fn);
787         else
788                 ret = fn();
789 
790         msgbuf[0] = 0;
791 
792         if (preempt_count() != count) {
793                 sprintf(msgbuf, "preemption imbalance ");
794                 preempt_count_set(count);
795         }
796         if (irqs_disabled()) {
797                 strlcat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
798                 local_irq_enable();
799         }
800         WARN(msgbuf[0], "initcall %pF returned with %s\n", fn, msgbuf);
801 
802         return ret;
803 }
804 
805 
806 extern initcall_t __initcall_start[];
807 extern initcall_t __initcall0_start[];
808 extern initcall_t __initcall1_start[];
809 extern initcall_t __initcall2_start[];
810 extern initcall_t __initcall3_start[];
811 extern initcall_t __initcall4_start[];
812 extern initcall_t __initcall5_start[];
813 extern initcall_t __initcall6_start[];
814 extern initcall_t __initcall7_start[];
815 extern initcall_t __initcall_end[];
816 
817 static initcall_t *initcall_levels[] __initdata = {
818         __initcall0_start,
819         __initcall1_start,
820         __initcall2_start,
821         __initcall3_start,
822         __initcall4_start,
823         __initcall5_start,
824         __initcall6_start,
825         __initcall7_start,
826         __initcall_end,
827 };
828 
829 /* Keep these in sync with initcalls in include/linux/init.h */
830 static char *initcall_level_names[] __initdata = {
831         "early",
832         "core",
833         "postcore",
834         "arch",
835         "subsys",
836         "fs",
837         "device",
838         "late",
839 };
840 
841 static void __init do_initcall_level(int level)
842 {
843         initcall_t *fn;
844 
845         strcpy(initcall_command_line, saved_command_line);
846         parse_args(initcall_level_names[level],
847                    initcall_command_line, __start___param,
848                    __stop___param - __start___param,
849                    level, level,
850                    &repair_env_string);
851 
852         for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
853                 do_one_initcall(*fn);
854 }
855 
856 static void __init do_initcalls(void)
857 {
858         int level;
859 
860         for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
861                 do_initcall_level(level);
862 }
863 
864 /*
865  * Ok, the machine is now initialized. None of the devices
866  * have been touched yet, but the CPU subsystem is up and
867  * running, and memory and process management works.
868  *
869  * Now we can finally start doing some real work..
870  */
871 static void __init do_basic_setup(void)
872 {
873         cpuset_init_smp();
874         usermodehelper_init();
875         shmem_init();
876         driver_init();
877         init_irq_proc();
878         do_ctors();
879         usermodehelper_enable();
880         do_initcalls();
881         random_int_secret_init();
882 }
883 
884 static void __init do_pre_smp_initcalls(void)
885 {
886         initcall_t *fn;
887 
888         for (fn = __initcall_start; fn < __initcall0_start; fn++)
889                 do_one_initcall(*fn);
890 }
891 
892 /*
893  * This function requests modules which should be loaded by default and is
894  * called twice right after initrd is mounted and right before init is
895  * exec'd.  If such modules are on either initrd or rootfs, they will be
896  * loaded before control is passed to userland.
897  */
898 void __init load_default_modules(void)
899 {
900         load_default_elevator_module();
901 }
902 
903 static int run_init_process(const char *init_filename)
904 {
905         argv_init[0] = init_filename;
906         return do_execve(getname_kernel(init_filename),
907                 (const char __user *const __user *)argv_init,
908                 (const char __user *const __user *)envp_init);
909 }
910 
911 static int try_to_run_init_process(const char *init_filename)
912 {
913         int ret;
914 
915         ret = run_init_process(init_filename);
916 
917         if (ret && ret != -ENOENT) {
918                 pr_err("Starting init: %s exists but couldn't execute it (error %d)\n",
919                        init_filename, ret);
920         }
921 
922         return ret;
923 }
924 
925 static noinline void __init kernel_init_freeable(void);
926 
927 static int __ref kernel_init(void *unused)
928 {
929         int ret;
930 
931         kernel_init_freeable();
932         /* need to finish all async __init code before freeing the memory */
933         async_synchronize_full();
934         free_initmem();
935         mark_rodata_ro();
936         system_state = SYSTEM_RUNNING;
937         numa_default_policy();
938 
939         flush_delayed_fput();
940 
941         if (ramdisk_execute_command) {
942                 ret = run_init_process(ramdisk_execute_command);
943                 if (!ret)
944                         return 0;
945                 pr_err("Failed to execute %s (error %d)\n",
946                        ramdisk_execute_command, ret);
947         }
948 
949         /*
950          * We try each of these until one succeeds.
951          *
952          * The Bourne shell can be used instead of init if we are
953          * trying to recover a really broken machine.
954          */
955         if (execute_command) {
956                 ret = run_init_process(execute_command);
957                 if (!ret)
958                         return 0;
959                 panic("Requested init %s failed (error %d).",
960                       execute_command, ret);
961         }
962         if (!try_to_run_init_process("/sbin/init") ||
963             !try_to_run_init_process("/etc/init") ||
964             !try_to_run_init_process("/bin/init") ||
965             !try_to_run_init_process("/bin/sh"))
966                 return 0;
967 
968         panic("No working init found.  Try passing init= option to kernel. "
969               "See Linux Documentation/init.txt for guidance.");
970 }
971 
972 static noinline void __init kernel_init_freeable(void)
973 {
974         /*
975          * Wait until kthreadd is all set-up.
976          */
977         wait_for_completion(&kthreadd_done);
978 
979         /* Now the scheduler is fully set up and can do blocking allocations */
980         gfp_allowed_mask = __GFP_BITS_MASK;
981 
982         /*
983          * init can allocate pages on any node
984          */
985         set_mems_allowed(node_states[N_MEMORY]);
986         /*
987          * init can run on any cpu.
988          */
989         set_cpus_allowed_ptr(current, cpu_all_mask);
990 
991         cad_pid = task_pid(current);
992 
993         smp_prepare_cpus(setup_max_cpus);
994 
995         do_pre_smp_initcalls();
996         lockup_detector_init();
997 
998         smp_init();
999         sched_init_smp();
1000 
1001         do_basic_setup();
1002 
1003         /* Open the /dev/console on the rootfs, this should never fail */
1004         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
1005                 pr_err("Warning: unable to open an initial console.\n");
1006 
1007         (void) sys_dup(0);
1008         (void) sys_dup(0);
1009         /*
1010          * check if there is an early userspace init.  If yes, let it do all
1011          * the work
1012          */
1013 
1014         if (!ramdisk_execute_command)
1015                 ramdisk_execute_command = "/init";
1016 
1017         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
1018                 ramdisk_execute_command = NULL;
1019                 prepare_namespace();
1020         }
1021 
1022         /*
1023          * Ok, we have completed the initial bootup, and
1024          * we're essentially up and running. Get rid of the
1025          * initmem segments and start the user-mode stuff..
1026          *
1027          * rootfs is available now, try loading the public keys
1028          * and default modules
1029          */
1030 
1031         integrity_load_keys();
1032         load_default_modules();
1033 }
1034 

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