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 #ifdef CONFIG_SMP
  70 static void smp_halt(void)
  71 {
  72         int cpuid = safe_smp_processor_id();
  73         static int first_entry = 1;
  74
  75         if (reboot_force)
  76                 return;
  77
  78         if (first_entry) {
  79                 first_entry = 0;
  80                 smp_call_function((void *)machine_restart, NULL, 1, 0);
  81         }
  82
  83         smp_stop_cpu();
  84
  85         /* AP calling this. Just halt */
  86         if (cpuid != boot_cpu_id) {
  87                 for (;;)
  88                         asm("hlt");
  89         }
  90
  91         /* Wait for all other CPUs to have run smp_stop_cpu */
  92         while (!cpus_empty(cpu_online_map))
  93                 rep_nop();
  94 }
  95 #endif
  96
  97 static inline void kb_wait(void)
  98 {
  99         int i;
 100
 101         for (i=0; i<0x10000; i++)
 102                 if ((inb_p(0x64) & 0x02) == 0)
 103                         break;
 104 }
 105
 106 void machine_restart(char * __unused)
 107 {
 108         int i;
 109
 110         printk("machine restart\n");
 111
 112 #ifdef CONFIG_SMP
 113         smp_halt();
 114 #endif
 115
 116         if (!reboot_force) {
 117                 local_irq_disable();
 118 #ifndef CONFIG_SMP
 119                 disable_local_APIC();
 120 #endif
 121                 disable_IO_APIC();
 122                 local_irq_enable();
 123         }
 124
 125         /* Tell the BIOS if we want cold or warm reboot */
 126         *((unsigned short *)__va(0x472)) = reboot_mode;
 127
 128         for (;;) {
 129                 /* Could also try the reset bit in the Hammer NB */
 130                 switch (reboot_type) {
 131                 case BOOT_KBD:
 132                 for (i=0; i<100; i++) {
 133                         kb_wait();
 134                         udelay(50);
 135                         outb(0xfe,0x64);         /* pulse reset low */
 136                         udelay(50);
 137                 }
 138
 139                 case BOOT_TRIPLE:
 140                         __asm__ __volatile__("lidt (%0)": :"r" (&no_idt));
 141                         __asm__ __volatile__("int3");
 142
 143                         reboot_type = BOOT_KBD;
 144                         break;
 145                 }
 146         }
 147 }
 148
 149 EXPORT_SYMBOL(machine_restart);
 150
 151 void machine_halt(void)
 152 {
 153 }
 154
 155 EXPORT_SYMBOL(machine_halt);
 156
 157 void machine_power_off(void)
 158 {
 159         if (pm_power_off)
 160                 pm_power_off();
 161 }
 162
 163 EXPORT_SYMBOL(machine_power_off);