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