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