arch/i386/kernel/reboot.c

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