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 __KERNEL_SYSCALLS__
  13
  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>
  50
  51 #include <asm/io.h>
  52 #include <asm/bugs.h>
  53 #include <asm/setup.h>
  54 #include <asm/sections.h>
  55 #include <asm/cacheflush.h>
  56
  57 #ifdef CONFIG_X86_LOCAL_APIC
  58 #include <asm/smp.h>
  59 #endif
  60
  61 /*
  62  * This is one of the first .c files built. Error out early if we have compiler
  63  * trouble.
  64  *
  65  * Versions of gcc older than that listed below may actually compile and link
  66  * okay, but the end product can have subtle run time bugs.  To avoid associated
  67  * bogus bug reports, we flatly refuse to compile with a gcc that is known to be
  68  * too old from the very beginning.
  69  */
  70 #if (__GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 2)
  71 #error Sorry, your GCC is too old. It builds incorrect kernels.
  72 #endif
  73
  74 static int init(void *);
  75
  76 extern void init_IRQ(void);
  77 extern void fork_init(unsigned long);
  78 extern void mca_init(void);
  79 extern void sbus_init(void);
  80 extern void sysctl_init(void);
  81 extern void signals_init(void);
  82 extern void buffer_init(void);
  83 extern void pidhash_init(void);
  84 extern void pidmap_init(void);
  85 extern void prio_tree_init(void);
  86 extern void radix_tree_init(void);
  87 extern void free_initmem(void);
  88 extern void populate_rootfs(void);
  89 extern void driver_init(void);
  90 extern void prepare_namespace(void);
  91 #ifdef  CONFIG_ACPI
  92 extern void acpi_early_init(void);
  93 #else
  94 static inline void acpi_early_init(void) { }
  95 #endif
  96 #ifndef CONFIG_DEBUG_RODATA
  97 static inline void mark_rodata_ro(void) { }
  98 #endif
  99
 100 #ifdef CONFIG_TC
 101 extern void tc_init(void);
 102 #endif
 103
 104 enum system_states system_state;
 105 EXPORT_SYMBOL(system_state);
 106
 107 /*
 108  * Boot command-line arguments
 109  */
 110 #define MAX_INIT_ARGS CONFIG_INIT_ENV_ARG_LIMIT
 111 #define MAX_INIT_ENVS CONFIG_INIT_ENV_ARG_LIMIT
 112
 113 extern void time_init(void);
 114 /* Default late time init is NULL. archs can override this later. */
 115 void (*late_time_init)(void);
 116 extern void softirq_init(void);
 117
 118 /* Untouched command line (eg. for /proc) saved by arch-specific code. */
 119 char saved_command_line[COMMAND_LINE_SIZE];
 120
 121 static char *execute_command;
 122 static char *ramdisk_execute_command;
 123
 124 /* Setup configured maximum number of CPUs to activate */
 125 static unsigned int max_cpus = NR_CPUS;
 126
 127 /*
 128  * Setup routine for controlling SMP activation
 129  *
 130  * Command-line option of "nosmp" or "maxcpus=0" will disable SMP
 131  * activation entirely (the MPS table probe still happens, though).
 132  *
 133  * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
 134  * greater than 0, limits the maximum number of CPUs activated in
 135  * SMP mode to <NUM>.
 136  */
 137 static int __init nosmp(char *str)
 138 {
 139         max_cpus = 0;
 140         return 1;
 141 }
 142
 143 __setup("nosmp", nosmp);
 144
 145 static int __init maxcpus(char *str)
 146 {
 147         get_option(&str, &max_cpus);
 148         return 1;
 149 }
 150
 151 __setup("maxcpus=", maxcpus);
 152
 153 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
 154 char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
 155 static const char *panic_later, *panic_param;
 156
 157 extern struct obs_kernel_param __setup_start[], __setup_end[];
 158
 159 static int __init obsolete_checksetup(char *line)
 160 {
 161         struct obs_kernel_param *p;
 162
 163         p = __setup_start;
 164         do {
 165                 int n = strlen(p->str);
 166                 if (!strncmp(line, p->str, n)) {
 167                         if (p->early) {
 168                                 /* Already done in parse_early_param?  (Needs
 169                                  * exact match on param part) */
 170                                 if (line[n] == '\0' || line[n] == '=')
 171                                         return 1;
 172                         } else if (!p->setup_func) {
 173                                 printk(KERN_WARNING "Parameter %s is obsolete,"
 174                                        " ignored\n", p->str);
 175                                 return 1;
 176                         } else if (p->setup_func(line + n))
 177                                 return 1;
 178                 }
 179                 p++;
 180         } while (p < __setup_end);
 181         return 0;
 182 }
 183
 184 /*
 185  * This should be approx 2 Bo*oMips to start (note initial shift), and will
 186  * still work even if initially too large, it will just take slightly longer
 187  */
 188 unsigned long loops_per_jiffy = (1<<12);
 189
 190 EXPORT_SYMBOL(loops_per_jiffy);
 191
 192 static int __init debug_kernel(char *str)
 193 {
 194         if (*str)
 195                 return 0;
 196         console_loglevel = 10;
 197         return 1;
 198 }
 199
 200 static int __init quiet_kernel(char *str)
 201 {
 202         if (*str)
 203                 return 0;
 204         console_loglevel = 4;
 205         return 1;
 206 }
 207
 208 __setup("debug", debug_kernel);
 209 __setup("quiet", quiet_kernel);
 210
 211 static int __init loglevel(char *str)
 212 {
 213         get_option(&str, &console_loglevel);
 214         return 1;
 215 }
 216
 217 __setup("loglevel=", loglevel);
 218
 219 /*
 220  * Unknown boot options get handed to init, unless they look like
 221  * failed parameters
 222  */
 223 static int __init unknown_bootoption(char *param, char *val)
 224 {
 225         /* Change NUL term back to "=", to make "param" the whole string. */
 226         if (val) {
 227                 /* param=val or param="val"? */
 228                 if (val == param+strlen(param)+1)
 229                         val[-1] = '=';
 230                 else if (val == param+strlen(param)+2) {
 231                         val[-2] = '=';
 232                         memmove(val-1, val, strlen(val)+1);
 233                         val--;
 234                 } else
 235                         BUG();
 236         }
 237
 238         /* Handle obsolete-style parameters */
 239         if (obsolete_checksetup(param))
 240                 return 0;
 241
 242         /*
 243          * Preemptive maintenance for "why didn't my mispelled command
 244          * line work?"
 245          */
 246         if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
 247                 printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
 248                 return 0;
 249         }
 250
 251         if (panic_later)
 252                 return 0;
 253
 254         if (val) {
 255                 /* Environment option */
 256                 unsigned int i;
 257                 for (i = 0; envp_init[i]; i++) {
 258                         if (i == MAX_INIT_ENVS) {
 259                                 panic_later = "Too many boot env vars at `%s'";
 260                                 panic_param = param;
 261                         }
 262                         if (!strncmp(param, envp_init[i], val - param))
 263                                 break;
 264                 }
 265                 envp_init[i] = param;
 266         } else {
 267                 /* Command line option */
 268                 unsigned int i;
 269                 for (i = 0; argv_init[i]; i++) {
 270                         if (i == MAX_INIT_ARGS) {
 271                                 panic_later = "Too many boot init vars at `%s'";
 272                                 panic_param = param;
 273                         }
 274                 }
 275                 argv_init[i] = param;
 276         }
 277         return 0;
 278 }
 279
 280 static int __init init_setup(char *str)
 281 {
 282         unsigned int i;
 283
 284         execute_command = str;
 285         /*
 286          * In case LILO is going to boot us with default command line,
 287          * it prepends "auto" before the whole cmdline which makes
 288          * the shell think it should execute a script with such name.
 289          * So we ignore all arguments entered _before_ init=... [MJ]
 290          */
 291         for (i = 1; i < MAX_INIT_ARGS; i++)
 292                 argv_init[i] = NULL;
 293         return 1;
 294 }
 295 __setup("init=", init_setup);
 296
 297 static int __init rdinit_setup(char *str)
 298 {
 299         unsigned int i;
 300
 301         ramdisk_execute_command = str;
 302         /* See "auto" comment in init_setup */
 303         for (i = 1; i < MAX_INIT_ARGS; i++)
 304                 argv_init[i] = NULL;
 305         return 1;
 306 }
 307 __setup("rdinit=", rdinit_setup);
 308
 309 extern void setup_arch(char **);
 310
 311 #ifndef CONFIG_SMP
 312
 313 #ifdef CONFIG_X86_LOCAL_APIC
 314 static void __init smp_init(void)
 315 {
 316         APIC_init_uniprocessor();
 317 }
 318 #else
 319 #define smp_init()      do { } while (0)
 320 #endif
 321
 322 static inline void setup_per_cpu_areas(void) { }
 323 static inline void smp_prepare_cpus(unsigned int maxcpus) { }
 324
 325 #else
 326
 327 #ifdef __GENERIC_PER_CPU
 328 unsigned long __per_cpu_offset[NR_CPUS];
 329
 330 EXPORT_SYMBOL(__per_cpu_offset);
 331
 332 static void __init setup_per_cpu_areas(void)
 333 {
 334         unsigned long size, i;
 335         char *ptr;
 336
 337         /* Copy section for each CPU (we discard the original) */
 338         size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
 339 #ifdef CONFIG_MODULES
 340         if (size < PERCPU_ENOUGH_ROOM)
 341                 size = PERCPU_ENOUGH_ROOM;
 342 #endif
 343
 344         ptr = alloc_bootmem(size * NR_CPUS);
 345
 346         for (i = 0; i < NR_CPUS; i++, ptr += size) {
 347                 __per_cpu_offset[i] = ptr - __per_cpu_start;
 348                 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
 349         }
 350 }
 351 #endif /* !__GENERIC_PER_CPU */
 352
 353 /* Called by boot processor to activate the rest. */
 354 static void __init smp_init(void)
 355 {
 356         unsigned int i;
 357
 358         /* FIXME: This should be done in userspace --RR */
 359         for_each_present_cpu(i) {
 360                 if (num_online_cpus() >= max_cpus)
 361                         break;
 362                 if (!cpu_online(i))
 363                         cpu_up(i);
 364         }
 365
 366         /* Any cleanup work */
 367         printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
 368         smp_cpus_done(max_cpus);
 369 #if 0
 370         /* Get other processors into their bootup holding patterns. */
 371
 372         smp_commence();
 373 #endif
 374 }
 375
 376 #endif
 377
 378 /*
 379  * We need to finalize in a non-__init function or else race conditions
 380  * between the root thread and the init thread may cause start_kernel to
 381  * be reaped by free_initmem before the root thread has proceeded to
 382  * cpu_idle.
 383  *
 384  * gcc-3.4 accidentally inlines this function, so use noinline.
 385  */
 386
 387 static void noinline rest_init(void)
 388         __releases(kernel_lock)
 389 {
 390         kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
 391         numa_default_policy();
 392         unlock_kernel();
 393
 394         /*
 395          * The boot idle thread must execute schedule()
 396          * at least one to get things moving:
 397          */
 398         preempt_enable_no_resched();
 399         schedule();
 400         preempt_disable();
 401
 402         /* Call into cpu_idle with preempt disabled */
 403         cpu_idle();
 404 }
 405
 406 /* Check for early params. */
 407 static int __init do_early_param(char *param, char *val)
 408 {
 409         struct obs_kernel_param *p;
 410
 411         for (p = __setup_start; p < __setup_end; p++) {
 412                 if (p->early && strcmp(param, p->str) == 0) {
 413                         if (p->setup_func(val) != 0)
 414                                 printk(KERN_WARNING
 415                                        "Malformed early option '%s'\n", param);
 416                 }
 417         }
 418         /* We accept everything at this stage. */
 419         return 0;
 420 }
 421
 422 /* Arch code calls this early on, or if not, just before other parsing. */
 423 void __init parse_early_param(void)
 424 {
 425         static __initdata int done = 0;
 426         static __initdata char tmp_cmdline[COMMAND_LINE_SIZE];
 427
 428         if (done)
 429                 return;
 430
 431         /* All fall through to do_early_param. */
 432         strlcpy(tmp_cmdline, saved_command_line, COMMAND_LINE_SIZE);
 433         parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
 434         done = 1;
 435 }
 436
 437 /*
 438  *      Activate the first processor.
 439  */
 440
 441 asmlinkage void __init start_kernel(void)
 442 {
 443         char * command_line;
 444         extern struct kernel_param __start___param[], __stop___param[];
 445 /*
 446  * Interrupts are still disabled. Do necessary setups, then
 447  * enable them
 448  */
 449         lock_kernel();
 450         page_address_init();
 451         printk(KERN_NOTICE);
 452         printk(linux_banner);
 453         setup_arch(&command_line);
 454         setup_per_cpu_areas();
 455
 456         /*
 457          * Mark the boot cpu "online" so that it can call console drivers in
 458          * printk() and can access its per-cpu storage.
 459          */
 460         smp_prepare_boot_cpu();
 461
 462         /*
 463          * Set up the scheduler prior starting any interrupts (such as the
 464          * timer interrupt). Full topology setup happens at smp_init()
 465          * time - but meanwhile we still have a functioning scheduler.
 466          */
 467         sched_init();
 468         /*
 469          * Disable preemption - early bootup scheduling is extremely
 470          * fragile until we cpu_idle() for the first time.
 471          */
 472         preempt_disable();
 473         build_all_zonelists();
 474         page_alloc_init();
 475         printk(KERN_NOTICE "Kernel command line: %s\n", saved_command_line);
 476         parse_early_param();
 477         parse_args("Booting kernel", command_line, __start___param,
 478                    __stop___param - __start___param,
 479                    &unknown_bootoption);
 480         sort_main_extable();
 481         trap_init();
 482         rcu_init();
 483         init_IRQ();
 484         pidhash_init();
 485         init_timers();
 486         hrtimers_init();
 487         softirq_init();
 488         time_init();
 489
 490         /*
 491          * HACK ALERT! This is early. We're enabling the console before
 492          * we've done PCI setups etc, and console_init() must be aware of
 493          * this. But we do want output early, in case something goes wrong.
 494          */
 495         console_init();
 496         if (panic_later)
 497                 panic(panic_later, panic_param);
 498         profile_init();
 499         local_irq_enable();
 500 #ifdef CONFIG_BLK_DEV_INITRD
 501         if (initrd_start && !initrd_below_start_ok &&
 502                         initrd_start < min_low_pfn << PAGE_SHIFT) {
 503                 printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
 504                     "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
 505                 initrd_start = 0;
 506         }
 507 #endif
 508         vfs_caches_init_early();
 509         cpuset_init_early();
 510         mem_init();
 511         kmem_cache_init();
 512         setup_per_cpu_pageset();
 513         numa_policy_init();
 514         if (late_time_init)
 515                 late_time_init();
 516         calibrate_delay();
 517         pidmap_init();
 518         pgtable_cache_init();
 519         prio_tree_init();
 520         anon_vma_init();
 521 #ifdef CONFIG_X86
 522         if (efi_enabled)
 523                 efi_enter_virtual_mode();
 524 #endif
 525         fork_init(num_physpages);
 526         proc_caches_init();
 527         buffer_init();
 528         unnamed_dev_init();
 529         key_init();
 530         security_init();
 531         vfs_caches_init(num_physpages);
 532         radix_tree_init();
 533         signals_init();
 534         /* rootfs populating might need page-writeback */
 535         page_writeback_init();
 536 #ifdef CONFIG_PROC_FS
 537         proc_root_init();
 538 #endif
 539         cpuset_init();
 540
 541         check_bugs();
 542
 543         acpi_early_init(); /* before LAPIC and SMP init */
 544
 545         /* Do the rest non-__init'ed, we're now alive */
 546         rest_init();
 547 }
 548
 549 static int __initdata initcall_debug;
 550
 551 static int __init initcall_debug_setup(char *str)
 552 {
 553         initcall_debug = 1;
 554         return 1;
 555 }
 556 __setup("initcall_debug", initcall_debug_setup);
 557
 558 struct task_struct *child_reaper = &init_task;
 559
 560 extern initcall_t __initcall_start[], __initcall_end[];
 561
 562 static void __init do_initcalls(void)
 563 {
 564         initcall_t *call;
 565         int count = preempt_count();
 566
 567         for (call = __initcall_start; call < __initcall_end; call++) {
 568                 char *msg;
 569
 570                 if (initcall_debug) {
 571                         printk(KERN_DEBUG "Calling initcall 0x%p", *call);
 572                         print_fn_descriptor_symbol(": %s()", (unsigned long) *call);
 573                         printk("\n");
 574                 }
 575
 576                 (*call)();
 577
 578                 msg = NULL;
 579                 if (preempt_count() != count) {
 580                         msg = "preemption imbalance";
 581                         preempt_count() = count;
 582                 }
 583                 if (irqs_disabled()) {
 584                         msg = "disabled interrupts";
 585                         local_irq_enable();
 586                 }
 587                 if (msg) {
 588                         printk(KERN_WARNING "error in initcall at 0x%p: "
 589                                 "returned with %s\n", *call, msg);
 590                 }
 591         }
 592
 593         /* Make sure there is no pending stuff from the initcall sequence */
 594         flush_scheduled_work();
 595 }
 596
 597 /*
 598  * Ok, the machine is now initialized. None of the devices
 599  * have been touched yet, but the CPU subsystem is up and
 600  * running, and memory and process management works.
 601  *
 602  * Now we can finally start doing some real work..
 603  */
 604 static void __init do_basic_setup(void)
 605 {
 606         /* drivers will send hotplug events */
 607         init_workqueues();
 608         usermodehelper_init();
 609         driver_init();
 610
 611 #ifdef CONFIG_SYSCTL
 612         sysctl_init();
 613 #endif
 614
 615         do_initcalls();
 616 }
 617
 618 static void do_pre_smp_initcalls(void)
 619 {
 620         extern int spawn_ksoftirqd(void);
 621 #ifdef CONFIG_SMP
 622         extern int migration_init(void);
 623
 624         migration_init();
 625 #endif
 626         spawn_ksoftirqd();
 627         spawn_softlockup_task();
 628 }
 629
 630 static void run_init_process(char *init_filename)
 631 {
 632         argv_init[0] = init_filename;
 633         execve(init_filename, argv_init, envp_init);
 634 }
 635
 636 static inline void fixup_cpu_present_map(void)
 637 {
 638 #ifdef CONFIG_SMP
 639         int i;
 640
 641         /*
 642          * If arch is not hotplug ready and did not populate
 643          * cpu_present_map, just make cpu_present_map same as cpu_possible_map
 644          * for other cpu bringup code to function as normal. e.g smp_init() etc.
 645          */
 646         if (cpus_empty(cpu_present_map)) {
 647                 for_each_cpu(i) {
 648                         cpu_set(i, cpu_present_map);
 649                 }
 650         }
 651 #endif
 652 }
 653
 654 static int init(void * unused)
 655 {
 656         lock_kernel();
 657         /*
 658          * init can run on any cpu.
 659          */
 660         set_cpus_allowed(current, CPU_MASK_ALL);
 661         /*
 662          * Tell the world that we're going to be the grim
 663          * reaper of innocent orphaned children.
 664          *
 665          * We don't want people to have to make incorrect
 666          * assumptions about where in the task array this
 667          * can be found.
 668          */
 669         child_reaper = current;
 670
 671         /* Sets up cpus_possible() */
 672         smp_prepare_cpus(max_cpus);
 673
 674         do_pre_smp_initcalls();
 675
 676         fixup_cpu_present_map();
 677         smp_init();
 678         sched_init_smp();
 679
 680         cpuset_init_smp();
 681
 682         /*
 683          * Do this before initcalls, because some drivers want to access
 684          * firmware files.
 685          */
 686         populate_rootfs();
 687
 688         do_basic_setup();
 689
 690         /*
 691          * check if there is an early userspace init.  If yes, let it do all
 692          * the work
 693          */
 694
 695         if (!ramdisk_execute_command)
 696                 ramdisk_execute_command = "/init";
 697
 698         if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
 699                 ramdisk_execute_command = NULL;
 700                 prepare_namespace();
 701         }
 702
 703         /*
 704          * Ok, we have completed the initial bootup, and
 705          * we're essentially up and running. Get rid of the
 706          * initmem segments and start the user-mode stuff..
 707          */
 708         free_initmem();
 709         unlock_kernel();
 710         mark_rodata_ro();
 711         system_state = SYSTEM_RUNNING;
 712         numa_default_policy();
 713
 714         if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 715                 printk(KERN_WARNING "Warning: unable to open an initial console.\n");
 716
 717         (void) sys_dup(0);
 718         (void) sys_dup(0);
 719
 720         if (ramdisk_execute_command) {
 721                 run_init_process(ramdisk_execute_command);
 722                 printk(KERN_WARNING "Failed to execute %s\n",
 723                                 ramdisk_execute_command);
 724         }
 725
 726         /*
 727          * We try each of these until one succeeds.
 728          *
 729          * The Bourne shell can be used instead of init if we are
 730          * trying to recover a really broken machine.
 731          */
 732         if (execute_command) {
 733                 run_init_process(execute_command);
 734                 printk(KERN_WARNING "Failed to execute %s.  Attempting "
 735                                         "defaults...\n", execute_command);
 736         }
 737         run_init_process("/sbin/init");
 738         run_init_process("/etc/init");
 739         run_init_process("/bin/init");
 740         run_init_process("/bin/sh");
 741
 742         panic("No init found.  Try passing init= option to kernel.");
 743 }