arch/x86/kernel/reboot.c

   1 #include <linux/module.h>
   2 #include <linux/init.h>
   3 #include <linux/reboot.h>
   4 #include <linux/init.h>
   5 #include <linux/pm.h>
   6 #include <linux/efi.h>
   7 #include <acpi/reboot.h>
   8 #include <asm/io.h>
   9 #include <asm/apic.h>
  10 #include <asm/desc.h>
  11 #include <asm/hpet.h>
  12 #include <asm/reboot_fixups.h>
  13 #include <asm/reboot.h>
  14
  15 #ifdef CONFIG_X86_32
  16 # include <linux/dmi.h>
  17 # include <linux/ctype.h>
  18 # include <linux/mc146818rtc.h>
  19 # include <asm/pgtable.h>
  20 #else
  21 # include <asm/iommu.h>
  22 #endif
  23
  24 /*
  25  * Power off function, if any
  26  */
  27 void (*pm_power_off)(void);
  28 EXPORT_SYMBOL(pm_power_off);
  29
  30 static long no_idt[3];
  31 static int reboot_mode;
  32 enum reboot_type reboot_type = BOOT_KBD;
  33 int reboot_force;
  34
  35 #if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
  36 static int reboot_cpu = -1;
  37 #endif
  38
  39 /* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old]
  40    warm   Don't set the cold reboot flag
  41    cold   Set the cold reboot flag
  42    bios   Reboot by jumping through the BIOS (only for X86_32)
  43    smp    Reboot by executing reset on BSP or other CPU (only for X86_32)
  44    triple Force a triple fault (init)
  45    kbd    Use the keyboard controller. cold reset (default)
  46    acpi   Use the RESET_REG in the FADT
  47    efi    Use efi reset_system runtime service
  48    force  Avoid anything that could hang.
  49  */
  50 static int __init reboot_setup(char *str)
  51 {
  52         for (;;) {
  53                 switch (*str) {
  54                 case 'w':
  55                         reboot_mode = 0x1234;
  56                         break;
  57
  58                 case 'c':
  59                         reboot_mode = 0;
  60                         break;
  61
  62 #ifdef CONFIG_X86_32
  63 #ifdef CONFIG_SMP
  64                 case 's':
  65                         if (isdigit(*(str+1))) {
  66                                 reboot_cpu = (int) (*(str+1) - '0');
  67                                 if (isdigit(*(str+2)))
  68                                         reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
  69                         }
  70                                 /* we will leave sorting out the final value
  71                                    when we are ready to reboot, since we might not
  72                                    have set up boot_cpu_id or smp_num_cpu */
  73                         break;
  74 #endif /* CONFIG_SMP */
  75
  76                 case 'b':
  77 #endif
  78                 case 'a':
  79                 case 'k':
  80                 case 't':
  81                 case 'e':
  82                         reboot_type = *str;
  83                         break;
  84
  85                 case 'f':
  86                         reboot_force = 1;
  87                         break;
  88                 }
  89
  90                 str = strchr(str, ',');
  91                 if (str)
  92                         str++;
  93                 else
  94                         break;
  95         }
  96         return 1;
  97 }
  98
  99 __setup("reboot=", reboot_setup);
 100
 101
 102 #ifdef CONFIG_X86_32
 103 /*
 104  * Reboot options and system auto-detection code provided by
 105  * Dell Inc. so their systems "just work". :-)
 106  */
 107
 108 /*
 109  * Some machines require the "reboot=b"  commandline option,
 110  * this quirk makes that automatic.
 111  */
 112 static int __init set_bios_reboot(const struct dmi_system_id *d)
 113 {
 114         if (reboot_type != BOOT_BIOS) {
 115                 reboot_type = BOOT_BIOS;
 116                 printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
 117         }
 118         return 0;
 119 }
 120
 121 static struct dmi_system_id __initdata reboot_dmi_table[] = {
 122         {       /* Handle problems with rebooting on Dell E520's */
 123                 .callback = set_bios_reboot,
 124                 .ident = "Dell E520",
 125                 .matches = {
 126                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 127                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
 128                 },
 129         },
 130         {       /* Handle problems with rebooting on Dell 1300's */
 131                 .callback = set_bios_reboot,
 132                 .ident = "Dell PowerEdge 1300",
 133                 .matches = {
 134                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 135                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 136                 },
 137         },
 138         {       /* Handle problems with rebooting on Dell 300's */
 139                 .callback = set_bios_reboot,
 140                 .ident = "Dell PowerEdge 300",
 141                 .matches = {
 142                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 143                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 144                 },
 145         },
 146         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF*/
 147                 .callback = set_bios_reboot,
 148                 .ident = "Dell OptiPlex 745",
 149                 .matches = {
 150                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 151                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 152                         DMI_MATCH(DMI_BOARD_NAME, "0WF810"),
 153                 },
 154         },
 155         {       /* Handle problems with rebooting on Dell 2400's */
 156                 .callback = set_bios_reboot,
 157                 .ident = "Dell PowerEdge 2400",
 158                 .matches = {
 159                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 160                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 161                 },
 162         },
 163         {       /* Handle problems with rebooting on HP laptops */
 164                 .callback = set_bios_reboot,
 165                 .ident = "HP Compaq Laptop",
 166                 .matches = {
 167                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 168                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 169                 },
 170         },
 171         { }
 172 };
 173
 174 static int __init reboot_init(void)
 175 {
 176         dmi_check_system(reboot_dmi_table);
 177         return 0;
 178 }
 179 core_initcall(reboot_init);
 180
 181 /* The following code and data reboots the machine by switching to real
 182    mode and jumping to the BIOS reset entry point, as if the CPU has
 183    really been reset.  The previous version asked the keyboard
 184    controller to pulse the CPU reset line, which is more thorough, but
 185    doesn't work with at least one type of 486 motherboard.  It is easy
 186    to stop this code working; hence the copious comments. */
 187 static unsigned long long
 188 real_mode_gdt_entries [3] =
 189 {
 190         0x0000000000000000ULL,  /* Null descriptor */
 191         0x00009a000000ffffULL,  /* 16-bit real-mode 64k code at 0x00000000 */
 192         0x000092000100ffffULL   /* 16-bit real-mode 64k data at 0x00000100 */
 193 };
 194
 195 static struct desc_ptr
 196 real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, (long)real_mode_gdt_entries },
 197 real_mode_idt = { 0x3ff, 0 };
 198
 199 /* This is 16-bit protected mode code to disable paging and the cache,
 200    switch to real mode and jump to the BIOS reset code.
 201
 202    The instruction that switches to real mode by writing to CR0 must be
 203    followed immediately by a far jump instruction, which set CS to a
 204    valid value for real mode, and flushes the prefetch queue to avoid
 205    running instructions that have already been decoded in protected
 206    mode.
 207
 208    Clears all the flags except ET, especially PG (paging), PE
 209    (protected-mode enable) and TS (task switch for coprocessor state
 210    save).  Flushes the TLB after paging has been disabled.  Sets CD and
 211    NW, to disable the cache on a 486, and invalidates the cache.  This
 212    is more like the state of a 486 after reset.  I don't know if
 213    something else should be done for other chips.
 214
 215    More could be done here to set up the registers as if a CPU reset had
 216    occurred; hopefully real BIOSs don't assume much. */
 217 static unsigned char real_mode_switch [] =
 218 {
 219         0x66, 0x0f, 0x20, 0xc0,                 /*    movl  %cr0,%eax        */
 220         0x66, 0x83, 0xe0, 0x11,                 /*    andl  $0x00000011,%eax */
 221         0x66, 0x0d, 0x00, 0x00, 0x00, 0x60,     /*    orl   $0x60000000,%eax */
 222         0x66, 0x0f, 0x22, 0xc0,                 /*    movl  %eax,%cr0        */
 223         0x66, 0x0f, 0x22, 0xd8,                 /*    movl  %eax,%cr3        */
 224         0x66, 0x0f, 0x20, 0xc3,                 /*    movl  %cr0,%ebx        */
 225         0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60,       /*    andl  $0x60000000,%ebx */
 226         0x74, 0x02,                             /*    jz    f                */
 227         0x0f, 0x09,                             /*    wbinvd                 */
 228         0x24, 0x10,                             /* f: andb  $0x10,al         */
 229         0x66, 0x0f, 0x22, 0xc0                  /*    movl  %eax,%cr0        */
 230 };
 231 static unsigned char jump_to_bios [] =
 232 {
 233         0xea, 0x00, 0x00, 0xff, 0xff            /*    ljmp  $0xffff,$0x0000  */
 234 };
 235
 236 /*
 237  * Switch to real mode and then execute the code
 238  * specified by the code and length parameters.
 239  * We assume that length will aways be less that 100!
 240  */
 241 void machine_real_restart(unsigned char *code, int length)
 242 {
 243         local_irq_disable();
 244
 245         /* Write zero to CMOS register number 0x0f, which the BIOS POST
 246            routine will recognize as telling it to do a proper reboot.  (Well
 247            that's what this book in front of me says -- it may only apply to
 248            the Phoenix BIOS though, it's not clear).  At the same time,
 249            disable NMIs by setting the top bit in the CMOS address register,
 250            as we're about to do peculiar things to the CPU.  I'm not sure if
 251            `outb_p' is needed instead of just `outb'.  Use it to be on the
 252            safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 253          */
 254         spin_lock(&rtc_lock);
 255         CMOS_WRITE(0x00, 0x8f);
 256         spin_unlock(&rtc_lock);
 257
 258         /* Remap the kernel at virtual address zero, as well as offset zero
 259            from the kernel segment.  This assumes the kernel segment starts at
 260            virtual address PAGE_OFFSET. */
 261         memcpy(swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
 262                 sizeof(swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
 263
 264         /*
 265          * Use `swapper_pg_dir' as our page directory.
 266          */
 267         load_cr3(swapper_pg_dir);
 268
 269         /* Write 0x1234 to absolute memory location 0x472.  The BIOS reads
 270            this on booting to tell it to "Bypass memory test (also warm
 271            boot)".  This seems like a fairly standard thing that gets set by
 272            REBOOT.COM programs, and the previous reset routine did this
 273            too. */
 274         *((unsigned short *)0x472) = reboot_mode;
 275
 276         /* For the switch to real mode, copy some code to low memory.  It has
 277            to be in the first 64k because it is running in 16-bit mode, and it
 278            has to have the same physical and virtual address, because it turns
 279            off paging.  Copy it near the end of the first page, out of the way
 280            of BIOS variables. */
 281         memcpy((void *)(0x1000 - sizeof(real_mode_switch) - 100),
 282                 real_mode_switch, sizeof (real_mode_switch));
 283         memcpy((void *)(0x1000 - 100), code, length);
 284
 285         /* Set up the IDT for real mode. */
 286         load_idt(&real_mode_idt);
 287
 288         /* Set up a GDT from which we can load segment descriptors for real
 289            mode.  The GDT is not used in real mode; it is just needed here to
 290            prepare the descriptors. */
 291         load_gdt(&real_mode_gdt);
 292
 293         /* Load the data segment registers, and thus the descriptors ready for
 294            real mode.  The base address of each segment is 0x100, 16 times the
 295            selector value being loaded here.  This is so that the segment
 296            registers don't have to be reloaded after switching to real mode:
 297            the values are consistent for real mode operation already. */
 298         __asm__ __volatile__ ("movl $0x0010,%%eax\n"
 299                                 "\tmovl %%eax,%%ds\n"
 300                                 "\tmovl %%eax,%%es\n"
 301                                 "\tmovl %%eax,%%fs\n"
 302                                 "\tmovl %%eax,%%gs\n"
 303                                 "\tmovl %%eax,%%ss" : : : "eax");
 304
 305         /* Jump to the 16-bit code that we copied earlier.  It disables paging
 306            and the cache, switches to real mode, and jumps to the BIOS reset
 307            entry point. */
 308         __asm__ __volatile__ ("ljmp $0x0008,%0"
 309                                 :
 310                                 : "i" ((void *)(0x1000 - sizeof (real_mode_switch) - 100)));
 311 }
 312 #ifdef CONFIG_APM_MODULE
 313 EXPORT_SYMBOL(machine_real_restart);
 314 #endif
 315
 316 #endif /* CONFIG_X86_32 */
 317
 318 static inline void kb_wait(void)
 319 {
 320         int i;
 321
 322         for (i = 0; i < 0x10000; i++) {
 323                 if ((inb(0x64) & 0x02) == 0)
 324                         break;
 325                 udelay(2);
 326         }
 327 }
 328
 329 static void native_machine_emergency_restart(void)
 330 {
 331         int i;
 332
 333         /* Tell the BIOS if we want cold or warm reboot */
 334         *((unsigned short *)__va(0x472)) = reboot_mode;
 335
 336         for (;;) {
 337                 /* Could also try the reset bit in the Hammer NB */
 338                 switch (reboot_type) {
 339                 case BOOT_KBD:
 340                         for (i = 0; i < 10; i++) {
 341                                 kb_wait();
 342                                 udelay(50);
 343                                 outb(0xfe, 0x64); /* pulse reset low */
 344                                 udelay(50);
 345                         }
 346
 347                 case BOOT_TRIPLE:
 348                         load_idt((const struct desc_ptr *)&no_idt);
 349                         __asm__ __volatile__("int3");
 350
 351                         reboot_type = BOOT_KBD;
 352                         break;
 353
 354 #ifdef CONFIG_X86_32
 355                 case BOOT_BIOS:
 356                         machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
 357
 358                         reboot_type = BOOT_KBD;
 359                         break;
 360 #endif
 361
 362                 case BOOT_ACPI:
 363                         acpi_reboot();
 364                         reboot_type = BOOT_KBD;
 365                         break;
 366
 367
 368                 case BOOT_EFI:
 369                         if (efi_enabled)
 370                                 efi.reset_system(reboot_mode ? EFI_RESET_WARM : EFI_RESET_COLD,
 371                                                  EFI_SUCCESS, 0, NULL);
 372
 373                         reboot_type = BOOT_KBD;
 374                         break;
 375                 }
 376         }
 377 }
 378
 379 static void native_machine_shutdown(void)
 380 {
 381         /* Stop the cpus and apics */
 382 #ifdef CONFIG_SMP
 383         int reboot_cpu_id;
 384
 385         /* The boot cpu is always logical cpu 0 */
 386         reboot_cpu_id = 0;
 387
 388 #ifdef CONFIG_X86_32
 389         /* See if there has been given a command line override */
 390         if ((reboot_cpu != -1) && (reboot_cpu < NR_CPUS) &&
 391                 cpu_isset(reboot_cpu, cpu_online_map))
 392                 reboot_cpu_id = reboot_cpu;
 393 #endif
 394
 395         /* Make certain the cpu I'm about to reboot on is online */
 396         if (!cpu_isset(reboot_cpu_id, cpu_online_map))
 397                 reboot_cpu_id = smp_processor_id();
 398
 399         /* Make certain I only run on the appropriate processor */
 400         set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
 401
 402         /* O.K Now that I'm on the appropriate processor,
 403          * stop all of the others.
 404          */
 405         smp_send_stop();
 406 #endif
 407
 408         lapic_shutdown();
 409
 410 #ifdef CONFIG_X86_IO_APIC
 411         disable_IO_APIC();
 412 #endif
 413
 414 #ifdef CONFIG_HPET_TIMER
 415         hpet_disable();
 416 #endif
 417
 418 #ifdef CONFIG_X86_64
 419         pci_iommu_shutdown();
 420 #endif
 421 }
 422
 423 static void native_machine_restart(char *__unused)
 424 {
 425         printk("machine restart\n");
 426
 427         if (!reboot_force)
 428                 machine_shutdown();
 429         machine_emergency_restart();
 430 }
 431
 432 static void native_machine_halt(void)
 433 {
 434 }
 435
 436 static void native_machine_power_off(void)
 437 {
 438         if (pm_power_off) {
 439                 if (!reboot_force)
 440                         machine_shutdown();
 441                 pm_power_off();
 442         }
 443 }
 444
 445 struct machine_ops machine_ops = {
 446         .power_off = native_machine_power_off,
 447         .shutdown = native_machine_shutdown,
 448         .emergency_restart = native_machine_emergency_restart,
 449         .restart = native_machine_restart,
 450         .halt = native_machine_halt
 451 };
 452
 453 void machine_power_off(void)
 454 {
 455         machine_ops.power_off();
 456 }
 457
 458 void machine_shutdown(void)
 459 {
 460         machine_ops.shutdown();
 461 }
 462
 463 void machine_emergency_restart(void)
 464 {
 465         machine_ops.emergency_restart();
 466 }
 467
 468 void machine_restart(char *cmd)
 469 {
 470         machine_ops.restart(cmd);
 471 }
 472
 473 void machine_halt(void)
 474 {
 475         machine_ops.halt();
 476 }
 477