arch/i386/kernel/reboot.c

   1 /*
   2  *  linux/arch/i386/kernel/reboot.c
   3  */
   4
   5 #include <linux/mm.h>
   6 #include <linux/module.h>
   7 #include <linux/delay.h>
   8 #include <linux/init.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/mc146818rtc.h>
  11 #include <linux/efi.h>
  12 #include <linux/dmi.h>
  13 #include <linux/ctype.h>
  14 #include <linux/pm.h>
  15 #include <linux/reboot.h>
  16 #include <asm/uaccess.h>
  17 #include <asm/apic.h>
  18 #include <asm/desc.h>
  19 #include "mach_reboot.h"
  20 #include <asm/reboot_fixups.h>
  21 #include <asm/reboot.h>
  22
  23 /*
  24  * Power off function, if any
  25  */
  26 void (*pm_power_off)(void);
  27 EXPORT_SYMBOL(pm_power_off);
  28
  29 static int reboot_mode;
  30 static int reboot_thru_bios;
  31
  32 #ifdef CONFIG_SMP
  33 static int reboot_cpu = -1;
  34 #endif
  35 static int __init reboot_setup(char *str)
  36 {
  37         while(1) {
  38                 switch (*str) {
  39                 case 'w': /* "warm" reboot (no memory testing etc) */
  40                         reboot_mode = 0x1234;
  41                         break;
  42                 case 'c': /* "cold" reboot (with memory testing etc) */
  43                         reboot_mode = 0x0;
  44                         break;
  45                 case 'b': /* "bios" reboot by jumping through the BIOS */
  46                         reboot_thru_bios = 1;
  47                         break;
  48                 case 'h': /* "hard" reboot by toggling RESET and/or crashing the CPU */
  49                         reboot_thru_bios = 0;
  50                         break;
  51 #ifdef CONFIG_SMP
  52                 case 's': /* "smp" reboot by executing reset on BSP or other CPU*/
  53                         if (isdigit(*(str+1))) {
  54                                 reboot_cpu = (int) (*(str+1) - '0');
  55                                 if (isdigit(*(str+2)))
  56                                         reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
  57                         }
  58                                 /* we will leave sorting out the final value
  59                                 when we are ready to reboot, since we might not
  60                                 have set up boot_cpu_id or smp_num_cpu */
  61                         break;
  62 #endif
  63                 }
  64                 if((str = strchr(str,',')) != NULL)
  65                         str++;
  66                 else
  67                         break;
  68         }
  69         return 1;
  70 }
  71
  72 __setup("reboot=", reboot_setup);
  73
  74 /*
  75  * Reboot options and system auto-detection code provided by
  76  * Dell Inc. so their systems "just work". :-)
  77  */
  78
  79 /*
  80  * Some machines require the "reboot=b"  commandline option, this quirk makes that automatic.
  81  */
  82 static int __init set_bios_reboot(struct dmi_system_id *d)
  83 {
  84         if (!reboot_thru_bios) {
  85                 reboot_thru_bios = 1;
  86                 printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
  87         }
  88         return 0;
  89 }
  90
  91 static struct dmi_system_id __initdata reboot_dmi_table[] = {
  92         {       /* Handle problems with rebooting on Dell 1300's */
  93                 .callback = set_bios_reboot,
  94                 .ident = "Dell PowerEdge 1300",
  95                 .matches = {
  96                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
  97                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
  98                 },
  99         },
 100         {       /* Handle problems with rebooting on Dell 300's */
 101                 .callback = set_bios_reboot,
 102                 .ident = "Dell PowerEdge 300",
 103                 .matches = {
 104                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 105                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
 106                 },
 107         },
 108         {       /* Handle problems with rebooting on Dell 2400's */
 109                 .callback = set_bios_reboot,
 110                 .ident = "Dell PowerEdge 2400",
 111                 .matches = {
 112                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
 113                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
 114                 },
 115         },
 116         {       /* Handle problems with rebooting on HP laptops */
 117                 .callback = set_bios_reboot,
 118                 .ident = "HP Compaq Laptop",
 119                 .matches = {
 120                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 121                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
 122                 },
 123         },
 124         { }
 125 };
 126
 127 static int __init reboot_init(void)
 128 {
 129         dmi_check_system(reboot_dmi_table);
 130         return 0;
 131 }
 132
 133 core_initcall(reboot_init);
 134
 135 /* The following code and data reboots the machine by switching to real
 136    mode and jumping to the BIOS reset entry point, as if the CPU has
 137    really been reset.  The previous version asked the keyboard
 138    controller to pulse the CPU reset line, which is more thorough, but
 139    doesn't work with at least one type of 486 motherboard.  It is easy
 140    to stop this code working; hence the copious comments. */
 141
 142 static unsigned long long
 143 real_mode_gdt_entries [3] =
 144 {
 145         0x0000000000000000ULL,  /* Null descriptor */
 146         0x00009a000000ffffULL,  /* 16-bit real-mode 64k code at 0x00000000 */
 147         0x000092000100ffffULL   /* 16-bit real-mode 64k data at 0x00000100 */
 148 };
 149
 150 static struct Xgt_desc_struct
 151 real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, (long)real_mode_gdt_entries },
 152 real_mode_idt = { 0x3ff, 0 },
 153 no_idt = { 0, 0 };
 154
 155
 156 /* This is 16-bit protected mode code to disable paging and the cache,
 157    switch to real mode and jump to the BIOS reset code.
 158
 159    The instruction that switches to real mode by writing to CR0 must be
 160    followed immediately by a far jump instruction, which set CS to a
 161    valid value for real mode, and flushes the prefetch queue to avoid
 162    running instructions that have already been decoded in protected
 163    mode.
 164
 165    Clears all the flags except ET, especially PG (paging), PE
 166    (protected-mode enable) and TS (task switch for coprocessor state
 167    save).  Flushes the TLB after paging has been disabled.  Sets CD and
 168    NW, to disable the cache on a 486, and invalidates the cache.  This
 169    is more like the state of a 486 after reset.  I don't know if
 170    something else should be done for other chips.
 171
 172    More could be done here to set up the registers as if a CPU reset had
 173    occurred; hopefully real BIOSs don't assume much. */
 174
 175 static unsigned char real_mode_switch [] =
 176 {
 177         0x66, 0x0f, 0x20, 0xc0,                 /*    movl  %cr0,%eax        */
 178         0x66, 0x83, 0xe0, 0x11,                 /*    andl  $0x00000011,%eax */
 179         0x66, 0x0d, 0x00, 0x00, 0x00, 0x60,     /*    orl   $0x60000000,%eax */
 180         0x66, 0x0f, 0x22, 0xc0,                 /*    movl  %eax,%cr0        */
 181         0x66, 0x0f, 0x22, 0xd8,                 /*    movl  %eax,%cr3        */
 182         0x66, 0x0f, 0x20, 0xc3,                 /*    movl  %cr0,%ebx        */
 183         0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60,       /*    andl  $0x60000000,%ebx */
 184         0x74, 0x02,                             /*    jz    f                */
 185         0x0f, 0x09,                             /*    wbinvd                 */
 186         0x24, 0x10,                             /* f: andb  $0x10,al         */
 187         0x66, 0x0f, 0x22, 0xc0                  /*    movl  %eax,%cr0        */
 188 };
 189 static unsigned char jump_to_bios [] =
 190 {
 191         0xea, 0x00, 0x00, 0xff, 0xff            /*    ljmp  $0xffff,$0x0000  */
 192 };
 193
 194 /*
 195  * Switch to real mode and then execute the code
 196  * specified by the code and length parameters.
 197  * We assume that length will aways be less that 100!
 198  */
 199 void machine_real_restart(unsigned char *code, int length)
 200 {
 201         unsigned long flags;
 202
 203         local_irq_disable();
 204
 205         /* Write zero to CMOS register number 0x0f, which the BIOS POST
 206            routine will recognize as telling it to do a proper reboot.  (Well
 207            that's what this book in front of me says -- it may only apply to
 208            the Phoenix BIOS though, it's not clear).  At the same time,
 209            disable NMIs by setting the top bit in the CMOS address register,
 210            as we're about to do peculiar things to the CPU.  I'm not sure if
 211            `outb_p' is needed instead of just `outb'.  Use it to be on the
 212            safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 213          */
 214
 215         spin_lock_irqsave(&rtc_lock, flags);
 216         CMOS_WRITE(0x00, 0x8f);
 217         spin_unlock_irqrestore(&rtc_lock, flags);
 218
 219         /* Remap the kernel at virtual address zero, as well as offset zero
 220            from the kernel segment.  This assumes the kernel segment starts at
 221            virtual address PAGE_OFFSET. */
 222
 223         memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
 224                 sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
 225
 226         /*
 227          * Use `swapper_pg_dir' as our page directory.
 228          */
 229         load_cr3(swapper_pg_dir);
 230
 231         /* Write 0x1234 to absolute memory location 0x472.  The BIOS reads
 232            this on booting to tell it to "Bypass memory test (also warm
 233            boot)".  This seems like a fairly standard thing that gets set by
 234            REBOOT.COM programs, and the previous reset routine did this
 235            too. */
 236
 237         *((unsigned short *)0x472) = reboot_mode;
 238
 239         /* For the switch to real mode, copy some code to low memory.  It has
 240            to be in the first 64k because it is running in 16-bit mode, and it
 241            has to have the same physical and virtual address, because it turns
 242            off paging.  Copy it near the end of the first page, out of the way
 243            of BIOS variables. */
 244
 245         memcpy ((void *) (0x1000 - sizeof (real_mode_switch) - 100),
 246                 real_mode_switch, sizeof (real_mode_switch));
 247         memcpy ((void *) (0x1000 - 100), code, length);
 248
 249         /* Set up the IDT for real mode. */
 250
 251         load_idt(&real_mode_idt);
 252
 253         /* Set up a GDT from which we can load segment descriptors for real
 254            mode.  The GDT is not used in real mode; it is just needed here to
 255            prepare the descriptors. */
 256
 257         load_gdt(&real_mode_gdt);
 258
 259         /* Load the data segment registers, and thus the descriptors ready for
 260            real mode.  The base address of each segment is 0x100, 16 times the
 261            selector value being loaded here.  This is so that the segment
 262            registers don't have to be reloaded after switching to real mode:
 263            the values are consistent for real mode operation already. */
 264
 265         __asm__ __volatile__ ("movl $0x0010,%%eax\n"
 266                                 "\tmovl %%eax,%%ds\n"
 267                                 "\tmovl %%eax,%%es\n"
 268                                 "\tmovl %%eax,%%fs\n"
 269                                 "\tmovl %%eax,%%gs\n"
 270                                 "\tmovl %%eax,%%ss" : : : "eax");
 271
 272         /* Jump to the 16-bit code that we copied earlier.  It disables paging
 273            and the cache, switches to real mode, and jumps to the BIOS reset
 274            entry point. */
 275
 276         __asm__ __volatile__ ("ljmp $0x0008,%0"
 277                                 :
 278                                 : "i" ((void *) (0x1000 - sizeof (real_mode_switch) - 100)));
 279 }
 280 #ifdef CONFIG_APM_MODULE
 281 EXPORT_SYMBOL(machine_real_restart);
 282 #endif
 283
 284 static void native_machine_shutdown(void)
 285 {
 286 #ifdef CONFIG_SMP
 287         int reboot_cpu_id;
 288
 289         /* The boot cpu is always logical cpu 0 */
 290         reboot_cpu_id = 0;
 291
 292         /* See if there has been given a command line override */
 293         if ((reboot_cpu != -1) && (reboot_cpu < NR_CPUS) &&
 294                 cpu_isset(reboot_cpu, cpu_online_map)) {
 295                 reboot_cpu_id = reboot_cpu;
 296         }
 297
 298         /* Make certain the cpu I'm rebooting on is online */
 299         if (!cpu_isset(reboot_cpu_id, cpu_online_map)) {
 300                 reboot_cpu_id = smp_processor_id();
 301         }
 302
 303         /* Make certain I only run on the appropriate processor */
 304         set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
 305
 306         /* O.K. Now that I'm on the appropriate processor, stop
 307          * all of the others, and disable their local APICs.
 308          */
 309
 310         smp_send_stop();
 311 #endif /* CONFIG_SMP */
 312
 313         lapic_shutdown();
 314
 315 #ifdef CONFIG_X86_IO_APIC
 316         disable_IO_APIC();
 317 #endif
 318 }
 319
 320 void __attribute__((weak)) mach_reboot_fixups(void)
 321 {
 322 }
 323
 324 static void native_machine_emergency_restart(void)
 325 {
 326         if (!reboot_thru_bios) {
 327                 if (efi_enabled) {
 328                         efi.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL);
 329                         load_idt(&no_idt);
 330                         __asm__ __volatile__("int3");
 331                 }
 332                 /* rebooting needs to touch the page at absolute addr 0 */
 333                 *((unsigned short *)__va(0x472)) = reboot_mode;
 334                 for (;;) {
 335                         mach_reboot_fixups(); /* for board specific fixups */
 336                         mach_reboot();
 337                         /* That didn't work - force a triple fault.. */
 338                         load_idt(&no_idt);
 339                         __asm__ __volatile__("int3");
 340                 }
 341         }
 342         if (efi_enabled)
 343                 efi.reset_system(EFI_RESET_WARM, EFI_SUCCESS, 0, NULL);
 344
 345         machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
 346 }
 347
 348 static void native_machine_restart(char * __unused)
 349 {
 350         machine_shutdown();
 351         machine_emergency_restart();
 352 }
 353
 354 static void native_machine_halt(void)
 355 {
 356 }
 357
 358 static void native_machine_power_off(void)
 359 {
 360         if (pm_power_off) {
 361                 machine_shutdown();
 362                 pm_power_off();
 363         }
 364 }
 365
 366
 367 struct machine_ops machine_ops = {
 368         .power_off = native_machine_power_off,
 369         .shutdown = native_machine_shutdown,
 370         .emergency_restart = native_machine_emergency_restart,
 371         .restart = native_machine_restart,
 372         .halt = native_machine_halt,
 373 };
 374
 375 void machine_power_off(void)
 376 {
 377         machine_ops.power_off();
 378 }
 379
 380 void machine_shutdown(void)
 381 {
 382         machine_ops.shutdown();
 383 }
 384
 385 void machine_emergency_restart(void)
 386 {
 387         machine_ops.emergency_restart();
 388 }
 389
 390 void machine_restart(char *cmd)
 391 {
 392         machine_ops.restart(cmd);
 393 }
 394
 395 void machine_halt(void)
 396 {
 397         machine_ops.halt();
 398 }