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