arch/x86_64/kernel/reboot.c

   1 /* Various gunk just to reboot the machine. */
   2 #include <linux/module.h>
   3 #include <linux/reboot.h>
   4 #include <linux/init.h>
   5 #include <linux/smp.h>
   6 #include <linux/kernel.h>
   7 #include <linux/ctype.h>
   8 #include <linux/string.h>
   9 #include <linux/pm.h>
  10 #include <linux/kdebug.h>
  11 #include <linux/sched.h>
  12 #include <asm/io.h>
  13 #include <asm/delay.h>
  14 #include <asm/hw_irq.h>
  15 #include <asm/system.h>
  16 #include <asm/pgtable.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/apic.h>
  19
  20 /*
  21  * Power off function, if any
  22  */
  23 void (*pm_power_off)(void);
  24 EXPORT_SYMBOL(pm_power_off);
  25
  26 static long no_idt[3];
  27 static enum {
  28         BOOT_TRIPLE = 't',
  29         BOOT_KBD = 'k'
  30 } reboot_type = BOOT_KBD;
  31 static int reboot_mode = 0;
  32 int reboot_force;
  33
  34 /* reboot=t[riple] | k[bd] [, [w]arm | [c]old]
  35    warm   Don't set the cold reboot flag
  36    cold   Set the cold reboot flag
  37    triple Force a triple fault (init)
  38    kbd    Use the keyboard controller. cold reset (default)
  39    force  Avoid anything that could hang.
  40  */
  41 static int __init reboot_setup(char *str)
  42 {
  43         for (;;) {
  44                 switch (*str) {
  45                 case 'w':
  46                         reboot_mode = 0x1234;
  47                         break;
  48
  49                 case 'c':
  50                         reboot_mode = 0;
  51                         break;
  52
  53                 case 't':
  54                 case 'b':
  55                 case 'k':
  56                         reboot_type = *str;
  57                         break;
  58                 case 'f':
  59                         reboot_force = 1;
  60                         break;
  61                 }
  62                 if((str = strchr(str,',')) != NULL)
  63                         str++;
  64                 else
  65                         break;
  66         }
  67         return 1;
  68 }
  69
  70 __setup("reboot=", reboot_setup);
  71
  72 static inline void kb_wait(void)
  73 {
  74         int i;
  75
  76         for (i=0; i<0x10000; i++)
  77                 if ((inb_p(0x64) & 0x02) == 0)
  78                         break;
  79 }
  80
  81 void machine_shutdown(void)
  82 {
  83         unsigned long flags;
  84         /* Stop the cpus and apics */
  85 #ifdef CONFIG_SMP
  86         int reboot_cpu_id;
  87
  88         /* The boot cpu is always logical cpu 0 */
  89         reboot_cpu_id = 0;
  90
  91         /* Make certain the cpu I'm about to reboot on is online */
  92         if (!cpu_isset(reboot_cpu_id, cpu_online_map)) {
  93                 reboot_cpu_id = smp_processor_id();
  94         }
  95
  96         /* Make certain I only run on the appropriate processor */
  97         set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
  98
  99         /* O.K Now that I'm on the appropriate processor,
 100          * stop all of the others.
 101          */
 102         smp_send_stop();
 103 #endif
 104
 105         local_irq_save(flags);
 106
 107 #ifndef CONFIG_SMP
 108         disable_local_APIC();
 109 #endif
 110
 111         disable_IO_APIC();
 112
 113         local_irq_restore(flags);
 114 }
 115
 116 void machine_emergency_restart(void)
 117 {
 118         int i;
 119
 120         /* Tell the BIOS if we want cold or warm reboot */
 121         *((unsigned short *)__va(0x472)) = reboot_mode;
 122
 123         for (;;) {
 124                 /* Could also try the reset bit in the Hammer NB */
 125                 switch (reboot_type) {
 126                 case BOOT_KBD:
 127                 for (i=0; i<10; i++) {
 128                         kb_wait();
 129                         udelay(50);
 130                         outb(0xfe,0x64);         /* pulse reset low */
 131                         udelay(50);
 132                 }
 133
 134                 case BOOT_TRIPLE:
 135                         __asm__ __volatile__("lidt (%0)": :"r" (&no_idt));
 136                         __asm__ __volatile__("int3");
 137
 138                         reboot_type = BOOT_KBD;
 139                         break;
 140                 }
 141         }
 142 }
 143
 144 void machine_restart(char * __unused)
 145 {
 146         printk("machine restart\n");
 147
 148         if (!reboot_force) {
 149                 machine_shutdown();
 150         }
 151         machine_emergency_restart();
 152 }
 153
 154 void machine_halt(void)
 155 {
 156 }
 157
 158 void machine_power_off(void)
 159 {
 160         if (pm_power_off) {
 161                 if (!reboot_force) {
 162                         machine_shutdown();
 163                 }
 164                 pm_power_off();
 165         }
 166 }
 167