blob: 629865ec0d469ff9886f67c8b1c7a4e2234e0d6f [file] [log] [blame]
/*
* linux/init/main.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* GK 2/5/95 - Changed to support mounting root fs via NFS
* Added initrd & change_root: Werner Almesberger & Hans Lermen, Feb '96
* Moan early if gcc is old, avoiding bogus kernels - Paul Gortmaker, May '96
* Simplified starting of init: Michael A. Griffith <grif@acm.org>
*/
#define __KERNEL_SYSCALLS__
#include <linux/config.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/kernel.h>
#include <linux/syscalls.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/utsname.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/initrd.h>
#include <linux/hdreg.h>
#include <linux/bootmem.h>
#include <linux/tty.h>
#include <linux/gfp.h>
#include <linux/percpu.h>
#include <linux/kernel_stat.h>
#include <linux/security.h>
#include <linux/workqueue.h>
#include <linux/profile.h>
#include <linux/rcupdate.h>
#include <linux/moduleparam.h>
#include <linux/kallsyms.h>
#include <linux/writeback.h>
#include <linux/cpu.h>
#include <linux/efi.h>
#include <linux/unistd.h>
#include <linux/rmap.h>
#include <asm/io.h>
#include <asm/bugs.h>
/*
* This is one of the first .c files built. Error out early
* if we have compiler trouble..
*/
#if __GNUC__ == 2 && __GNUC_MINOR__ == 96
#ifdef CONFIG_FRAME_POINTER
#error This compiler cannot compile correctly with frame pointers enabled
#endif
#endif
#ifdef CONFIG_X86_LOCAL_APIC
#include <asm/smp.h>
#endif
/*
* Versions of gcc older than that listed below may actually compile
* and link okay, but the end product can have subtle run time bugs.
* To avoid associated bogus bug reports, we flatly refuse to compile
* with a gcc that is known to be too old from the very beginning.
*/
#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 95)
#error Sorry, your GCC is too old. It builds incorrect kernels.
#endif
extern char *linux_banner;
static int init(void *);
extern void init_IRQ(void);
extern void sock_init(void);
extern void fork_init(unsigned long);
extern void mca_init(void);
extern void sbus_init(void);
extern void sysctl_init(void);
extern void signals_init(void);
extern void buffer_init(void);
extern void pidhash_init(void);
extern void pidmap_init(void);
extern void prio_tree_init(void);
extern void radix_tree_init(void);
extern void free_initmem(void);
extern void populate_rootfs(void);
extern void driver_init(void);
extern void prepare_namespace(void);
#ifdef CONFIG_TC
extern void tc_init(void);
#endif
enum system_states system_state;
EXPORT_SYMBOL(system_state);
/*
* Boot command-line arguments
*/
#define MAX_INIT_ARGS 8
#define MAX_INIT_ENVS 8
extern void time_init(void);
/* Default late time init is NULL. archs can override this later. */
void (*late_time_init)(void);
extern void softirq_init(void);
static char *execute_command;
/* Setup configured maximum number of CPUs to activate */
static unsigned int max_cpus = NR_CPUS;
/*
* Setup routine for controlling SMP activation
*
* Command-line option of "nosmp" or "maxcpus=0" will disable SMP
* activation entirely (the MPS table probe still happens, though).
*
* Command-line option of "maxcpus=<NUM>", where <NUM> is an integer
* greater than 0, limits the maximum number of CPUs activated in
* SMP mode to <NUM>.
*/
static int __init nosmp(char *str)
{
max_cpus = 0;
return 1;
}
__setup("nosmp", nosmp);
static int __init maxcpus(char *str)
{
get_option(&str, &max_cpus);
return 1;
}
__setup("maxcpus=", maxcpus);
static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, };
static const char *panic_later, *panic_param;
__setup("profile=", profile_setup);
static int __init obsolete_checksetup(char *line)
{
struct obs_kernel_param *p;
extern struct obs_kernel_param __setup_start, __setup_end;
p = &__setup_start;
do {
int n = strlen(p->str);
if (!strncmp(line, p->str, n)) {
if (!p->setup_func) {
printk(KERN_WARNING "Parameter %s is obsolete, ignored\n", p->str);
return 1;
} else if (p->setup_func(line + n))
return 1;
}
p++;
} while (p < &__setup_end);
return 0;
}
/* this should be approx 2 Bo*oMips to start (note initial shift), and will
still work even if initially too large, it will just take slightly longer */
unsigned long loops_per_jiffy = (1<<12);
EXPORT_SYMBOL(loops_per_jiffy);
/* This is the number of bits of precision for the loops_per_jiffy. Each
bit takes on average 1.5/HZ seconds. This (like the original) is a little
better than 1% */
#define LPS_PREC 8
void __devinit calibrate_delay(void)
{
unsigned long ticks, loopbit;
int lps_precision = LPS_PREC;
loops_per_jiffy = (1<<12);
printk("Calibrating delay loop... ");
while (loops_per_jiffy <<= 1) {
/* wait for "start of" clock tick */
ticks = jiffies;
while (ticks == jiffies)
/* nothing */;
/* Go .. */
ticks = jiffies;
__delay(loops_per_jiffy);
ticks = jiffies - ticks;
if (ticks)
break;
}
/* Do a binary approximation to get loops_per_jiffy set to equal one clock
(up to lps_precision bits) */
loops_per_jiffy >>= 1;
loopbit = loops_per_jiffy;
while ( lps_precision-- && (loopbit >>= 1) ) {
loops_per_jiffy |= loopbit;
ticks = jiffies;
while (ticks == jiffies);
ticks = jiffies;
__delay(loops_per_jiffy);
if (jiffies != ticks) /* longer than 1 tick */
loops_per_jiffy &= ~loopbit;
}
/* Round the value and print it */
printk("%lu.%02lu BogoMIPS\n",
loops_per_jiffy/(500000/HZ),
(loops_per_jiffy/(5000/HZ)) % 100);
}
static int __init debug_kernel(char *str)
{
if (*str)
return 0;
console_loglevel = 10;
return 1;
}
static int __init quiet_kernel(char *str)
{
if (*str)
return 0;
console_loglevel = 4;
return 1;
}
__setup("debug", debug_kernel);
__setup("quiet", quiet_kernel);
/* Unknown boot options get handed to init, unless they look like
failed parameters */
static int __init unknown_bootoption(char *param, char *val)
{
/* Change NUL term back to "=", to make "param" the whole string. */
if (val)
val[-1] = '=';
/* Handle obsolete-style parameters */
if (obsolete_checksetup(param))
return 0;
/* Preemptive maintenance for "why didn't my mispelled command
line work?" */
if (strchr(param, '.') && (!val || strchr(param, '.') < val)) {
printk(KERN_ERR "Unknown boot option `%s': ignoring\n", param);
return 0;
}
if (panic_later)
return 0;
if (val) {
/* Environment option */
unsigned int i;
for (i = 0; envp_init[i]; i++) {
if (i == MAX_INIT_ENVS) {
panic_later = "Too many boot env vars at `%s'";
panic_param = param;
}
}
envp_init[i] = param;
} else {
/* Command line option */
unsigned int i;
for (i = 0; argv_init[i]; i++) {
if (i == MAX_INIT_ARGS) {
panic_later = "Too many boot init vars at `%s'";
panic_param = param;
}
}
argv_init[i] = param;
}
return 0;
}
static int __init init_setup(char *str)
{
unsigned int i;
execute_command = str;
/* In case LILO is going to boot us with default command line,
* it prepends "auto" before the whole cmdline which makes
* the shell think it should execute a script with such name.
* So we ignore all arguments entered _before_ init=... [MJ]
*/
for (i = 1; i < MAX_INIT_ARGS; i++)
argv_init[i] = NULL;
return 1;
}
__setup("init=", init_setup);
extern void setup_arch(char **);
extern void cpu_idle(void);
#ifndef CONFIG_SMP
#ifdef CONFIG_X86_LOCAL_APIC
static void __init smp_init(void)
{
APIC_init_uniprocessor();
}
#else
#define smp_init() do { } while (0)
#endif
static inline void setup_per_cpu_areas(void) { }
static inline void smp_prepare_cpus(unsigned int maxcpus) { }
#else
#ifdef __GENERIC_PER_CPU
unsigned long __per_cpu_offset[NR_CPUS];
EXPORT_SYMBOL(__per_cpu_offset);
static void __init setup_per_cpu_areas(void)
{
unsigned long size, i;
char *ptr;
/* Created by linker magic */
extern char __per_cpu_start[], __per_cpu_end[];
/* Copy section for each CPU (we discard the original) */
size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
#ifdef CONFIG_MODULES
if (size < PERCPU_ENOUGH_ROOM)
size = PERCPU_ENOUGH_ROOM;
#endif
ptr = alloc_bootmem(size * NR_CPUS);
for (i = 0; i < NR_CPUS; i++, ptr += size) {
__per_cpu_offset[i] = ptr - __per_cpu_start;
memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
}
}
#endif /* !__GENERIC_PER_CPU */
/* Called by boot processor to activate the rest. */
static void __init smp_init(void)
{
unsigned int i;
/* FIXME: This should be done in userspace --RR */
for_each_present_cpu(i) {
if (num_online_cpus() >= max_cpus)
break;
if (!cpu_online(i))
cpu_up(i);
}
/* Any cleanup work */
printk("Brought up %ld CPUs\n", (long)num_online_cpus());
smp_cpus_done(max_cpus);
#if 0
/* Get other processors into their bootup holding patterns. */
smp_threads_ready=1;
smp_commence();
#endif
}
#endif
/*
* We need to finalize in a non-__init function or else race conditions
* between the root thread and the init thread may cause start_kernel to
* be reaped by free_initmem before the root thread has proceeded to
* cpu_idle.
*
* gcc-3.4 accidentally inlines this function, so use noinline.
*/
static void noinline rest_init(void)
{
kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
unlock_kernel();
cpu_idle();
}
/*
* Activate the first processor.
*/
asmlinkage void __init start_kernel(void)
{
char * command_line;
extern char saved_command_line[];
extern struct kernel_param __start___param[], __stop___param[];
/*
* Interrupts are still disabled. Do necessary setups, then
* enable them
*/
lock_kernel();
page_address_init();
printk(linux_banner);
setup_arch(&command_line);
setup_per_cpu_areas();
/*
* Mark the boot cpu "online" so that it can call console drivers in
* printk() and can access its per-cpu storage.
*/
smp_prepare_boot_cpu();
/*
* Set up the scheduler prior starting any interrupts (such as the
* timer interrupt). Full topology setup happens at smp_init()
* time - but meanwhile we still have a functioning scheduler.
*/
sched_init();
build_all_zonelists();
page_alloc_init();
printk("Kernel command line: %s\n", saved_command_line);
parse_args("Booting kernel", command_line, __start___param,
__stop___param - __start___param,
&unknown_bootoption);
sort_main_extable();
trap_init();
rcu_init();
init_IRQ();
pidhash_init();
init_timers();
softirq_init();
time_init();
/*
* HACK ALERT! This is early. We're enabling the console before
* we've done PCI setups etc, and console_init() must be aware of
* this. But we do want output early, in case something goes wrong.
*/
console_init();
if (panic_later)
panic(panic_later, panic_param);
profile_init();
local_irq_enable();
#ifdef CONFIG_BLK_DEV_INITRD
if (initrd_start && !initrd_below_start_ok &&
initrd_start < min_low_pfn << PAGE_SHIFT) {
printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
"disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
initrd_start = 0;
}
#endif
mem_init();
kmem_cache_init();
if (late_time_init)
late_time_init();
calibrate_delay();
pidmap_init();
pgtable_cache_init();
prio_tree_init();
anon_vma_init();
#ifdef CONFIG_X86
if (efi_enabled)
efi_enter_virtual_mode();
#endif
fork_init(num_physpages);
proc_caches_init();
buffer_init();
unnamed_dev_init();
security_scaffolding_startup();
vfs_caches_init(num_physpages);
radix_tree_init();
signals_init();
/* rootfs populating might need page-writeback */
page_writeback_init();
#ifdef CONFIG_PROC_FS
proc_root_init();
#endif
check_bugs();
printk("POSIX conformance testing by UNIFIX\n");
/*
* We count on the initial thread going ok
* Like idlers init is an unlocked kernel thread, which will
* make syscalls (and thus be locked).
*/
init_idle(current, smp_processor_id());
/* Do the rest non-__init'ed, we're now alive */
rest_init();
}
static int __initdata initcall_debug;
static int __init initcall_debug_setup(char *str)
{
initcall_debug = 1;
return 1;
}
__setup("initcall_debug", initcall_debug_setup);
struct task_struct *child_reaper = &init_task;
extern initcall_t __initcall_start, __initcall_end;
static void __init do_initcalls(void)
{
initcall_t *call;
int count = preempt_count();
for (call = &__initcall_start; call < &__initcall_end; call++) {
char *msg;
if (initcall_debug) {
printk(KERN_DEBUG "Calling initcall 0x%p", *call);
print_symbol(": %s()", (unsigned long) *call);
printk("\n");
}
(*call)();
msg = NULL;
if (preempt_count() != count) {
msg = "preemption imbalance";
preempt_count() = count;
}
if (irqs_disabled()) {
msg = "disabled interrupts";
local_irq_enable();
}
if (msg) {
printk("error in initcall at 0x%p: "
"returned with %s\n", *call, msg);
}
}
/* Make sure there is no pending stuff from the initcall sequence */
flush_scheduled_work();
}
/*
* Ok, the machine is now initialized. None of the devices
* have been touched yet, but the CPU subsystem is up and
* running, and memory and process management works.
*
* Now we can finally start doing some real work..
*/
static void __init do_basic_setup(void)
{
driver_init();
#ifdef CONFIG_SYSCTL
sysctl_init();
#endif
/* Networking initialization needs a process context */
sock_init();
init_workqueues();
do_initcalls();
}
static void do_pre_smp_initcalls(void)
{
extern int spawn_ksoftirqd(void);
#ifdef CONFIG_SMP
extern int migration_init(void);
migration_init();
#endif
spawn_ksoftirqd();
}
static void run_init_process(char *init_filename)
{
argv_init[0] = init_filename;
execve(init_filename, argv_init, envp_init);
}
static inline void fixup_cpu_present_map(void)
{
#ifdef CONFIG_SMP
int i;
/*
* If arch is not hotplug ready and did not populate
* cpu_present_map, just make cpu_present_map same as cpu_possible_map
* for other cpu bringup code to function as normal. e.g smp_init() etc.
*/
if (cpus_empty(cpu_present_map)) {
for_each_cpu(i) {
cpu_set(i, cpu_present_map);
}
}
#endif
}
static int init(void * unused)
{
lock_kernel();
/*
* Tell the world that we're going to be the grim
* reaper of innocent orphaned children.
*
* We don't want people to have to make incorrect
* assumptions about where in the task array this
* can be found.
*/
child_reaper = current;
/* Sets up cpus_possible() */
smp_prepare_cpus(max_cpus);
do_pre_smp_initcalls();
fixup_cpu_present_map();
smp_init();
sched_init_smp();
/*
* Do this before initcalls, because some drivers want to access
* firmware files.
*/
populate_rootfs();
do_basic_setup();
/*
* check if there is an early userspace init. If yes, let it do all
* the work
*/
if (sys_access("/init", 0) == 0)
execute_command = "/init";
else
prepare_namespace();
/*
* Ok, we have completed the initial bootup, and
* we're essentially up and running. Get rid of the
* initmem segments and start the user-mode stuff..
*/
free_initmem();
unlock_kernel();
system_state = SYSTEM_RUNNING;
if (sys_open("/dev/console", O_RDWR, 0) < 0)
printk("Warning: unable to open an initial console.\n");
(void) sys_dup(0);
(void) sys_dup(0);
/*
* We try each of these until one succeeds.
*
* The Bourne shell can be used instead of init if we are
* trying to recover a really broken machine.
*/
if (execute_command)
run_init_process(execute_command);
run_init_process("/sbin/init");
run_init_process("/etc/init");
run_init_process("/bin/init");
run_init_process("/bin/sh");
panic("No init found. Try passing init= option to kernel.");
}