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