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