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         local_irq_disable();
 202
 203         /* Write zero to CMOS register number 0x0f, which the BIOS POST
 204            routine will recognize as telling it to do a proper reboot.  (Well
 205            that's what this book in front of me says -- it may only apply to
 206            the Phoenix BIOS though, it's not clear).  At the same time,
 207            disable NMIs by setting the top bit in the CMOS address register,
 208            as we're about to do peculiar things to the CPU.  I'm not sure if
 209            `outb_p' is needed instead of just `outb'.  Use it to be on the
 210            safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 211          */
 212
 213         spin_lock(&rtc_lock);
 214         CMOS_WRITE(0x00, 0x8f);
 215         spin_unlock(&rtc_lock);
 216
 217         /* Remap the kernel at virtual address zero, as well as offset zero
 218            from the kernel segment.  This assumes the kernel segment starts at
 219            virtual address PAGE_OFFSET. */
 220
 221         memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
 222                 sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
 223
 224         /*
 225          * Use `swapper_pg_dir' as our page directory.
 226          */
 227         load_cr3(swapper_pg_dir);
 228
 229         /* Write 0x1234 to absolute memory location 0x472.  The BIOS reads
 230            this on booting to tell it to "Bypass memory test (also warm
 231            boot)".  This seems like a fairly standard thing that gets set by
 232            REBOOT.COM programs, and the previous reset routine did this
 233            too. */
 234
 235         *((unsigned short *)0x472) = reboot_mode;
 236
 237         /* For the switch to real mode, copy some code to low memory.  It has
 238            to be in the first 64k because it is running in 16-bit mode, and it
 239            has to have the same physical and virtual address, because it turns
 240            off paging.  Copy it near the end of the first page, out of the way
 241            of BIOS variables. */
 242
 243         memcpy ((void *) (0x1000 - sizeof (real_mode_switch) - 100),
 244                 real_mode_switch, sizeof (real_mode_switch));
 245         memcpy ((void *) (0x1000 - 100), code, length);
 246
 247         /* Set up the IDT for real mode. */
 248
 249         load_idt(&real_mode_idt);
 250
 251         /* Set up a GDT from which we can load segment descriptors for real
 252            mode.  The GDT is not used in real mode; it is just needed here to
 253            prepare the descriptors. */
 254
 255         load_gdt(&real_mode_gdt);
 256
 257         /* Load the data segment registers, and thus the descriptors ready for
 258            real mode.  The base address of each segment is 0x100, 16 times the
 259            selector value being loaded here.  This is so that the segment
 260            registers don't have to be reloaded after switching to real mode:
 261            the values are consistent for real mode operation already. */
 262
 263         __asm__ __volatile__ ("movl $0x0010,%%eax\n"
 264                                 "\tmovl %%eax,%%ds\n"
 265                                 "\tmovl %%eax,%%es\n"
 266                                 "\tmovl %%eax,%%fs\n"
 267                                 "\tmovl %%eax,%%gs\n"
 268                                 "\tmovl %%eax,%%ss" : : : "eax");
 269
 270         /* Jump to the 16-bit code that we copied earlier.  It disables paging
 271            and the cache, switches to real mode, and jumps to the BIOS reset
 272            entry point. */
 273
 274         __asm__ __volatile__ ("ljmp $0x0008,%0"
 275                                 :
 276                                 : "i" ((void *) (0x1000 - sizeof (real_mode_switch) - 100)));
 277 }
 278 #ifdef CONFIG_APM_MODULE
 279 EXPORT_SYMBOL(machine_real_restart);
 280 #endif
 281
 282 static void native_machine_shutdown(void)
 283 {
 284 #ifdef CONFIG_SMP
 285         int reboot_cpu_id;
 286
 287         /* The boot cpu is always logical cpu 0 */
 288         reboot_cpu_id = 0;
 289
 290         /* See if there has been given a command line override */
 291         if ((reboot_cpu != -1) && (reboot_cpu < NR_CPUS) &&
 292                 cpu_isset(reboot_cpu, cpu_online_map)) {
 293                 reboot_cpu_id = reboot_cpu;
 294         }
 295
 296         /* Make certain the cpu I'm rebooting on is online */
 297         if (!cpu_isset(reboot_cpu_id, cpu_online_map)) {
 298                 reboot_cpu_id = smp_processor_id();
 299         }
 300
 301         /* Make certain I only run on the appropriate processor */
 302         set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
 303
 304         /* O.K. Now that I'm on the appropriate processor, stop
 305          * all of the others, and disable their local APICs.
 306          */
 307
 308         smp_send_stop();
 309 #endif /* CONFIG_SMP */
 310
 311         lapic_shutdown();
 312
 313 #ifdef CONFIG_X86_IO_APIC
 314         disable_IO_APIC();
 315 #endif
 316 }
 317
 318 void __attribute__((weak)) mach_reboot_fixups(void)
 319 {
 320 }
 321
 322 static void native_machine_emergency_restart(void)
 323 {
 324         if (!reboot_thru_bios) {
 325                 if (efi_enabled) {
 326                         efi.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL);
 327                         load_idt(&no_idt);
 328                         __asm__ __volatile__("int3");
 329                 }
 330                 /* rebooting needs to touch the page at absolute addr 0 */
 331                 *((unsigned short *)__va(0x472)) = reboot_mode;
 332                 for (;;) {
 333                         mach_reboot_fixups(); /* for board specific fixups */
 334                         mach_reboot();
 335                         /* That didn't work - force a triple fault.. */
 336                         load_idt(&no_idt);
 337                         __asm__ __volatile__("int3");
 338                 }
 339         }
 340         if (efi_enabled)
 341                 efi.reset_system(EFI_RESET_WARM, EFI_SUCCESS, 0, NULL);
 342
 343         machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
 344 }
 345
 346 static void native_machine_restart(char * __unused)
 347 {
 348         machine_shutdown();
 349         machine_emergency_restart();
 350 }
 351
 352 static void native_machine_halt(void)
 353 {
 354 }
 355
 356 static void native_machine_power_off(void)
 357 {
 358         if (pm_power_off) {
 359                 machine_shutdown();
 360                 pm_power_off();
 361         }
 362 }
 363
 364
 365 struct machine_ops machine_ops = {
 366         .power_off = native_machine_power_off,
 367         .shutdown = native_machine_shutdown,
 368         .emergency_restart = native_machine_emergency_restart,
 369         .restart = native_machine_restart,
 370         .halt = native_machine_halt,
 371 };
 372
 373 void machine_power_off(void)
 374 {
 375         machine_ops.power_off();
 376 }
 377
 378 void machine_shutdown(void)
 379 {
 380         machine_ops.shutdown();
 381 }
 382
 383 void machine_emergency_restart(void)
 384 {
 385         machine_ops.emergency_restart();
 386 }
 387
 388 void machine_restart(char *cmd)
 389 {
 390         machine_ops.restart(cmd);
 391 }
 392
 393 void machine_halt(void)
 394 {
 395         machine_ops.halt();
 396 }