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 <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 Xgt_desc_struct
 150 real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, (long)real_mode_gdt_entries },
 151 real_mode_idt = { 0x3ff, 0 },
 152 no_idt = { 0, 0 };
 153
 154
 155 /* This is 16-bit protected mode code to disable paging and the cache,
 156    switch to real mode and jump to the BIOS reset code.
 157
 158    The instruction that switches to real mode by writing to CR0 must be
 159    followed immediately by a far jump instruction, which set CS to a
 160    valid value for real mode, and flushes the prefetch queue to avoid
 161    running instructions that have already been decoded in protected
 162    mode.
 163
 164    Clears all the flags except ET, especially PG (paging), PE
 165    (protected-mode enable) and TS (task switch for coprocessor state
 166    save).  Flushes the TLB after paging has been disabled.  Sets CD and
 167    NW, to disable the cache on a 486, and invalidates the cache.  This
 168    is more like the state of a 486 after reset.  I don't know if
 169    something else should be done for other chips.
 170
 171    More could be done here to set up the registers as if a CPU reset had
 172    occurred; hopefully real BIOSs don't assume much. */
 173
 174 static unsigned char real_mode_switch [] =
 175 {
 176         0x66, 0x0f, 0x20, 0xc0,                 /*    movl  %cr0,%eax        */
 177         0x66, 0x83, 0xe0, 0x11,                 /*    andl  $0x00000011,%eax */
 178         0x66, 0x0d, 0x00, 0x00, 0x00, 0x60,     /*    orl   $0x60000000,%eax */
 179         0x66, 0x0f, 0x22, 0xc0,                 /*    movl  %eax,%cr0        */
 180         0x66, 0x0f, 0x22, 0xd8,                 /*    movl  %eax,%cr3        */
 181         0x66, 0x0f, 0x20, 0xc3,                 /*    movl  %cr0,%ebx        */
 182         0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60,       /*    andl  $0x60000000,%ebx */
 183         0x74, 0x02,                             /*    jz    f                */
 184         0x0f, 0x09,                             /*    wbinvd                 */
 185         0x24, 0x10,                             /* f: andb  $0x10,al         */
 186         0x66, 0x0f, 0x22, 0xc0                  /*    movl  %eax,%cr0        */
 187 };
 188 static unsigned char jump_to_bios [] =
 189 {
 190         0xea, 0x00, 0x00, 0xff, 0xff            /*    ljmp  $0xffff,$0x0000  */
 191 };
 192
 193 /*
 194  * Switch to real mode and then execute the code
 195  * specified by the code and length parameters.
 196  * We assume that length will aways be less that 100!
 197  */
 198 void machine_real_restart(unsigned char *code, int length)
 199 {
 200         unsigned long flags;
 201
 202         local_irq_disable();
 203
 204         /* Write zero to CMOS register number 0x0f, which the BIOS POST
 205            routine will recognize as telling it to do a proper reboot.  (Well
 206            that's what this book in front of me says -- it may only apply to
 207            the Phoenix BIOS though, it's not clear).  At the same time,
 208            disable NMIs by setting the top bit in the CMOS address register,
 209            as we're about to do peculiar things to the CPU.  I'm not sure if
 210            `outb_p' is needed instead of just `outb'.  Use it to be on the
 211            safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 212          */
 213
 214         spin_lock_irqsave(&rtc_lock, flags);
 215         CMOS_WRITE(0x00, 0x8f);
 216         spin_unlock_irqrestore(&rtc_lock, flags);
 217
 218         /* Remap the kernel at virtual address zero, as well as offset zero
 219            from the kernel segment.  This assumes the kernel segment starts at
 220            virtual address PAGE_OFFSET. */
 221
 222         memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
 223                 sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
 224
 225         /*
 226          * Use `swapper_pg_dir' as our page directory.
 227          */
 228         load_cr3(swapper_pg_dir);
 229
 230         /* Write 0x1234 to absolute memory location 0x472.  The BIOS reads
 231            this on booting to tell it to "Bypass memory test (also warm
 232            boot)".  This seems like a fairly standard thing that gets set by
 233            REBOOT.COM programs, and the previous reset routine did this
 234            too. */
 235
 236         *((unsigned short *)0x472) = reboot_mode;
 237
 238         /* For the switch to real mode, copy some code to low memory.  It has
 239            to be in the first 64k because it is running in 16-bit mode, and it
 240            has to have the same physical and virtual address, because it turns
 241            off paging.  Copy it near the end of the first page, out of the way
 242            of BIOS variables. */
 243
 244         memcpy ((void *) (0x1000 - sizeof (real_mode_switch) - 100),
 245                 real_mode_switch, sizeof (real_mode_switch));
 246         memcpy ((void *) (0x1000 - 100), code, length);
 247
 248         /* Set up the IDT for real mode. */
 249
 250         load_idt(&real_mode_idt);
 251
 252         /* Set up a GDT from which we can load segment descriptors for real
 253            mode.  The GDT is not used in real mode; it is just needed here to
 254            prepare the descriptors. */
 255
 256         load_gdt(&real_mode_gdt);
 257
 258         /* Load the data segment registers, and thus the descriptors ready for
 259            real mode.  The base address of each segment is 0x100, 16 times the
 260            selector value being loaded here.  This is so that the segment
 261            registers don't have to be reloaded after switching to real mode:
 262            the values are consistent for real mode operation already. */
 263
 264         __asm__ __volatile__ ("movl $0x0010,%%eax\n"
 265                                 "\tmovl %%eax,%%ds\n"
 266                                 "\tmovl %%eax,%%es\n"
 267                                 "\tmovl %%eax,%%fs\n"
 268                                 "\tmovl %%eax,%%gs\n"
 269                                 "\tmovl %%eax,%%ss" : : : "eax");
 270
 271         /* Jump to the 16-bit code that we copied earlier.  It disables paging
 272            and the cache, switches to real mode, and jumps to the BIOS reset
 273            entry point. */
 274
 275         __asm__ __volatile__ ("ljmp $0x0008,%0"
 276                                 :
 277                                 : "i" ((void *) (0x1000 - sizeof (real_mode_switch) - 100)));
 278 }
 279 #ifdef CONFIG_APM_MODULE
 280 EXPORT_SYMBOL(machine_real_restart);
 281 #endif
 282
 283 void machine_shutdown(void)
 284 {
 285 #ifdef CONFIG_SMP
 286         int reboot_cpu_id;
 287
 288         /* The boot cpu is always logical cpu 0 */
 289         reboot_cpu_id = 0;
 290
 291         /* See if there has been given a command line override */
 292         if ((reboot_cpu != -1) && (reboot_cpu < NR_CPUS) &&
 293                 cpu_isset(reboot_cpu, cpu_online_map)) {
 294                 reboot_cpu_id = reboot_cpu;
 295         }
 296
 297         /* Make certain the cpu I'm rebooting on is online */
 298         if (!cpu_isset(reboot_cpu_id, cpu_online_map)) {
 299                 reboot_cpu_id = smp_processor_id();
 300         }
 301
 302         /* Make certain I only run on the appropriate processor */
 303         set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
 304
 305         /* O.K. Now that I'm on the appropriate processor, stop
 306          * all of the others, and disable their local APICs.
 307          */
 308
 309         smp_send_stop();
 310 #endif /* CONFIG_SMP */
 311
 312         lapic_shutdown();
 313
 314 #ifdef CONFIG_X86_IO_APIC
 315         disable_IO_APIC();
 316 #endif
 317 }
 318
 319 void machine_emergency_restart(void)
 320 {
 321         if (!reboot_thru_bios) {
 322                 if (efi_enabled) {
 323                         efi.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL);
 324                         load_idt(&no_idt);
 325                         __asm__ __volatile__("int3");
 326                 }
 327                 /* rebooting needs to touch the page at absolute addr 0 */
 328                 *((unsigned short *)__va(0x472)) = reboot_mode;
 329                 for (;;) {
 330                         mach_reboot_fixups(); /* for board specific fixups */
 331                         mach_reboot();
 332                         /* That didn't work - force a triple fault.. */
 333                         load_idt(&no_idt);
 334                         __asm__ __volatile__("int3");
 335                 }
 336         }
 337         if (efi_enabled)
 338                 efi.reset_system(EFI_RESET_WARM, EFI_SUCCESS, 0, NULL);
 339
 340         machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
 341 }
 342
 343 void machine_restart(char * __unused)
 344 {
 345         machine_shutdown();
 346         machine_emergency_restart();
 347 }
 348
 349 void machine_halt(void)
 350 {
 351 }
 352
 353 void machine_power_off(void)
 354 {
 355         if (pm_power_off) {
 356                 machine_shutdown();
 357                 pm_power_off();
 358         }
 359 }
 360
 361