arch/x86/kernel/reboot_32.c

   1 #include <linux/mm.h>
   2 #include <linux/module.h>
   3 #include <linux/delay.h>
   4 #include <linux/init.h>
   5 #include <linux/interrupt.h>
   6 #include <linux/mc146818rtc.h>
   7 #include <linux/efi.h>
   8 #include <linux/dmi.h>
   9 #include <linux/ctype.h>
  10 #include <linux/pm.h>
  11 #include <linux/reboot.h>
  12 #include <asm/uaccess.h>
  13 #include <asm/apic.h>
  14 #include <asm/hpet.h>
  15 #include <asm/desc.h>
  16 #include "mach_reboot.h"
  17 #include <asm/reboot_fixups.h>
  18 #include <asm/reboot.h>
  19
  20 /*
  21  * Power off function, if any
  22  */
  23 void (*pm_power_off)(void);
  24 EXPORT_SYMBOL(pm_power_off);
  25
  26 static int reboot_mode;
  27 static int reboot_thru_bios;
  28
  29 #ifdef CONFIG_SMP
  30 static int reboot_cpu = -1;
  31 #endif
  32 static int __init reboot_setup(char *str)
  33 {
  34         while(1) {
  35                 switch (*str) {
  36                 case 'w': /* "warm" reboot (no memory testing etc) */
  37                         reboot_mode = 0x1234;
  38                         break;
  39                 case 'c': /* "cold" reboot (with memory testing etc) */
  40                         reboot_mode = 0x0;
  41                         break;
  42                 case 'b': /* "bios" reboot by jumping through the BIOS */
  43                         reboot_thru_bios = 1;
  44                         break;
  45                 case 'h': /* "hard" reboot by toggling RESET and/or crashing the CPU */
  46                         reboot_thru_bios = 0;
  47                         break;
  48 #ifdef CONFIG_SMP
  49                 case 's': /* "smp" reboot by executing reset on BSP or other CPU*/
  50                         if (isdigit(*(str+1))) {
  51                                 reboot_cpu = (int) (*(str+1) - '0');
  52                                 if (isdigit(*(str+2)))
  53                                         reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
  54                         }
  55                                 /* we will leave sorting out the final value
  56                                 when we are ready to reboot, since we might not
  57                                 have set up boot_cpu_id or smp_num_cpu */
  58                         break;
  59 #endif
  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 /*
  72  * Reboot options and system auto-detection code provided by
  73  * Dell Inc. so their systems "just work". :-)
  74  */
  75
  76 /*
  77  * Some machines require the "reboot=b"  commandline option, this quirk makes that automatic.
  78  */
  79 static int __init set_bios_reboot(const struct dmi_system_id *d)
  80 {
  81         if (!reboot_thru_bios) {
  82                 reboot_thru_bios = 1;
  83                 printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
  84         }
  85         return 0;
  86 }
  87
  88 static struct dmi_system_id __initdata reboot_dmi_table[] = {
  89         {       /* Handle problems with rebooting on Dell E520's */
  90                 .callback = set_bios_reboot,
  91                 .ident = "Dell E520",
  92                 .matches = {
  93                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
  94                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
  95                 },
  96         },
  97         {       /* Handle problems with rebooting on Dell 1300's */
  98                 .callback = set_bios_reboot,
  99                 .ident = "Dell PowerEdge 1300",
 100                 .matches = {
 101                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 102                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
 103                 },
 104         },
 105         {       /* Handle problems with rebooting on Dell 300's */
 106                 .callback = set_bios_reboot,
 107                 .ident = "Dell PowerEdge 300",
 108                 .matches = {
 109                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 110                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 111                 },
 112         },
 113         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF*/
 114                 .callback = set_bios_reboot,
 115                 .ident = "Dell OptiPlex 745",
 116                 .matches = {
 117                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 118                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
 119                         DMI_MATCH(DMI_BOARD_NAME, "0WF810"),
 120                 },
 121         },
 122         {       /* Handle problems with rebooting on Dell 2400's */
 123                 .callback = set_bios_reboot,
 124                 .ident = "Dell PowerEdge 2400",
 125                 .matches = {
 126                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 127                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 128                 },
 129         },
 130         {       /* Handle problems with rebooting on HP laptops */
 131                 .callback = set_bios_reboot,
 132                 .ident = "HP Compaq Laptop",
 133                 .matches = {
 134                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 135                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 136                 },
 137         },
 138         { }
 139 };
 140
 141 static int __init reboot_init(void)
 142 {
 143         dmi_check_system(reboot_dmi_table);
 144         return 0;
 145 }
 146
 147 core_initcall(reboot_init);
 148
 149 /* The following code and data reboots the machine by switching to real
 150    mode and jumping to the BIOS reset entry point, as if the CPU has
 151    really been reset.  The previous version asked the keyboard
 152    controller to pulse the CPU reset line, which is more thorough, but
 153    doesn't work with at least one type of 486 motherboard.  It is easy
 154    to stop this code working; hence the copious comments. */
 155
 156 static unsigned long long
 157 real_mode_gdt_entries [3] =
 158 {
 159         0x0000000000000000ULL,  /* Null descriptor */
 160         0x00009a000000ffffULL,  /* 16-bit real-mode 64k code at 0x00000000 */
 161         0x000092000100ffffULL   /* 16-bit real-mode 64k data at 0x00000100 */
 162 };
 163
 164 static struct Xgt_desc_struct
 165 real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, (long)real_mode_gdt_entries },
 166 real_mode_idt = { 0x3ff, 0 },
 167 no_idt = { 0, 0 };
 168
 169
 170 /* This is 16-bit protected mode code to disable paging and the cache,
 171    switch to real mode and jump to the BIOS reset code.
 172
 173    The instruction that switches to real mode by writing to CR0 must be
 174    followed immediately by a far jump instruction, which set CS to a
 175    valid value for real mode, and flushes the prefetch queue to avoid
 176    running instructions that have already been decoded in protected
 177    mode.
 178
 179    Clears all the flags except ET, especially PG (paging), PE
 180    (protected-mode enable) and TS (task switch for coprocessor state
 181    save).  Flushes the TLB after paging has been disabled.  Sets CD and
 182    NW, to disable the cache on a 486, and invalidates the cache.  This
 183    is more like the state of a 486 after reset.  I don't know if
 184    something else should be done for other chips.
 185
 186    More could be done here to set up the registers as if a CPU reset had
 187    occurred; hopefully real BIOSs don't assume much. */
 188
 189 static unsigned char real_mode_switch [] =
 190 {
 191         0x66, 0x0f, 0x20, 0xc0,                 /*    movl  %cr0,%eax        */
 192         0x66, 0x83, 0xe0, 0x11,                 /*    andl  $0x00000011,%eax */
 193         0x66, 0x0d, 0x00, 0x00, 0x00, 0x60,     /*    orl   $0x60000000,%eax */
 194         0x66, 0x0f, 0x22, 0xc0,                 /*    movl  %eax,%cr0        */
 195         0x66, 0x0f, 0x22, 0xd8,                 /*    movl  %eax,%cr3        */
 196         0x66, 0x0f, 0x20, 0xc3,                 /*    movl  %cr0,%ebx        */
 197         0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60,       /*    andl  $0x60000000,%ebx */
 198         0x74, 0x02,                             /*    jz    f                */
 199         0x0f, 0x09,                             /*    wbinvd                 */
 200         0x24, 0x10,                             /* f: andb  $0x10,al         */
 201         0x66, 0x0f, 0x22, 0xc0                  /*    movl  %eax,%cr0        */
 202 };
 203 static unsigned char jump_to_bios [] =
 204 {
 205         0xea, 0x00, 0x00, 0xff, 0xff            /*    ljmp  $0xffff,$0x0000  */
 206 };
 207
 208 /*
 209  * Switch to real mode and then execute the code
 210  * specified by the code and length parameters.
 211  * We assume that length will aways be less that 100!
 212  */
 213 void machine_real_restart(unsigned char *code, int length)
 214 {
 215         local_irq_disable();
 216
 217         /* Write zero to CMOS register number 0x0f, which the BIOS POST
 218            routine will recognize as telling it to do a proper reboot.  (Well
 219            that's what this book in front of me says -- it may only apply to
 220            the Phoenix BIOS though, it's not clear).  At the same time,
 221            disable NMIs by setting the top bit in the CMOS address register,
 222            as we're about to do peculiar things to the CPU.  I'm not sure if
 223            `outb_p' is needed instead of just `outb'.  Use it to be on the
 224            safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 225          */
 226
 227         spin_lock(&rtc_lock);
 228         CMOS_WRITE(0x00, 0x8f);
 229         spin_unlock(&rtc_lock);
 230
 231         /* Remap the kernel at virtual address zero, as well as offset zero
 232            from the kernel segment.  This assumes the kernel segment starts at
 233            virtual address PAGE_OFFSET. */
 234
 235         memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
 236                 sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
 237
 238         /*
 239          * Use `swapper_pg_dir' as our page directory.
 240          */
 241         load_cr3(swapper_pg_dir);
 242
 243         /* Write 0x1234 to absolute memory location 0x472.  The BIOS reads
 244            this on booting to tell it to "Bypass memory test (also warm
 245            boot)".  This seems like a fairly standard thing that gets set by
 246            REBOOT.COM programs, and the previous reset routine did this
 247            too. */
 248
 249         *((unsigned short *)0x472) = reboot_mode;
 250
 251         /* For the switch to real mode, copy some code to low memory.  It has
 252            to be in the first 64k because it is running in 16-bit mode, and it
 253            has to have the same physical and virtual address, because it turns
 254            off paging.  Copy it near the end of the first page, out of the way
 255            of BIOS variables. */
 256
 257         memcpy ((void *) (0x1000 - sizeof (real_mode_switch) - 100),
 258                 real_mode_switch, sizeof (real_mode_switch));
 259         memcpy ((void *) (0x1000 - 100), code, length);
 260
 261         /* Set up the IDT for real mode. */
 262
 263         load_idt(&real_mode_idt);
 264
 265         /* Set up a GDT from which we can load segment descriptors for real
 266            mode.  The GDT is not used in real mode; it is just needed here to
 267            prepare the descriptors. */
 268
 269         load_gdt(&real_mode_gdt);
 270
 271         /* Load the data segment registers, and thus the descriptors ready for
 272            real mode.  The base address of each segment is 0x100, 16 times the
 273            selector value being loaded here.  This is so that the segment
 274            registers don't have to be reloaded after switching to real mode:
 275            the values are consistent for real mode operation already. */
 276
 277         __asm__ __volatile__ ("movl $0x0010,%%eax\n"
 278                                 "\tmovl %%eax,%%ds\n"
 279                                 "\tmovl %%eax,%%es\n"
 280                                 "\tmovl %%eax,%%fs\n"
 281                                 "\tmovl %%eax,%%gs\n"
 282                                 "\tmovl %%eax,%%ss" : : : "eax");
 283
 284         /* Jump to the 16-bit code that we copied earlier.  It disables paging
 285            and the cache, switches to real mode, and jumps to the BIOS reset
 286            entry point. */
 287
 288         __asm__ __volatile__ ("ljmp $0x0008,%0"
 289                                 :
 290                                 : "i" ((void *) (0x1000 - sizeof (real_mode_switch) - 100)));
 291 }
 292 #ifdef CONFIG_APM_MODULE
 293 EXPORT_SYMBOL(machine_real_restart);
 294 #endif
 295
 296 static void native_machine_shutdown(void)
 297 {
 298 #ifdef CONFIG_SMP
 299         int reboot_cpu_id;
 300
 301         /* The boot cpu is always logical cpu 0 */
 302         reboot_cpu_id = 0;
 303
 304         /* See if there has been given a command line override */
 305         if ((reboot_cpu != -1) && (reboot_cpu < NR_CPUS) &&
 306                 cpu_isset(reboot_cpu, cpu_online_map)) {
 307                 reboot_cpu_id = reboot_cpu;
 308         }
 309
 310         /* Make certain the cpu I'm rebooting on is online */
 311         if (!cpu_isset(reboot_cpu_id, cpu_online_map)) {
 312                 reboot_cpu_id = smp_processor_id();
 313         }
 314
 315         /* Make certain I only run on the appropriate processor */
 316         set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
 317
 318         /* O.K. Now that I'm on the appropriate processor, stop
 319          * all of the others, and disable their local APICs.
 320          */
 321
 322         smp_send_stop();
 323 #endif /* CONFIG_SMP */
 324
 325         lapic_shutdown();
 326
 327 #ifdef CONFIG_X86_IO_APIC
 328         disable_IO_APIC();
 329 #endif
 330 #ifdef CONFIG_HPET_TIMER
 331         hpet_disable();
 332 #endif
 333 }
 334
 335 void __attribute__((weak)) mach_reboot_fixups(void)
 336 {
 337 }
 338
 339 static void native_machine_emergency_restart(void)
 340 {
 341         if (!reboot_thru_bios) {
 342                 if (efi_enabled) {
 343                         efi.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL);
 344                         load_idt(&no_idt);
 345                         __asm__ __volatile__("int3");
 346                 }
 347                 /* rebooting needs to touch the page at absolute addr 0 */
 348                 *((unsigned short *)__va(0x472)) = reboot_mode;
 349                 for (;;) {
 350                         mach_reboot_fixups(); /* for board specific fixups */
 351                         mach_reboot();
 352                         /* That didn't work - force a triple fault.. */
 353                         load_idt(&no_idt);
 354                         __asm__ __volatile__("int3");
 355                 }
 356         }
 357         if (efi_enabled)
 358                 efi.reset_system(EFI_RESET_WARM, EFI_SUCCESS, 0, NULL);
 359
 360         machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
 361 }
 362
 363 static void native_machine_restart(char * __unused)
 364 {
 365         machine_shutdown();
 366         machine_emergency_restart();
 367 }
 368
 369 static void native_machine_halt(void)
 370 {
 371 }
 372
 373 static void native_machine_power_off(void)
 374 {
 375         if (pm_power_off) {
 376                 machine_shutdown();
 377                 pm_power_off();
 378         }
 379 }
 380
 381
 382 struct machine_ops machine_ops = {
 383         .power_off = native_machine_power_off,
 384         .shutdown = native_machine_shutdown,
 385         .emergency_restart = native_machine_emergency_restart,
 386         .restart = native_machine_restart,
 387         .halt = native_machine_halt,
 388 };
 389
 390 void machine_power_off(void)
 391 {
 392         machine_ops.power_off();
 393 }
 394
 395 void machine_shutdown(void)
 396 {
 397         machine_ops.shutdown();
 398 }
 399
 400 void machine_emergency_restart(void)
 401 {
 402         machine_ops.emergency_restart();
 403 }
 404
 405 void machine_restart(char *cmd)
 406 {
 407         machine_ops.restart(cmd);
 408 }
 409
 410 void machine_halt(void)
 411 {
 412         machine_ops.halt();
 413 }