xref: /linux/arch/x86/kernel/reboot.c (revision 26b0d14106954ae46d2f4f7eec3481828a210f7d)
1 #include <linux/module.h>
2 #include <linux/reboot.h>
3 #include <linux/init.h>
4 #include <linux/pm.h>
5 #include <linux/efi.h>
6 #include <linux/dmi.h>
7 #include <linux/sched.h>
8 #include <linux/tboot.h>
9 #include <linux/delay.h>
10 #include <acpi/reboot.h>
11 #include <asm/io.h>
12 #include <asm/apic.h>
13 #include <asm/desc.h>
14 #include <asm/hpet.h>
15 #include <asm/pgtable.h>
16 #include <asm/proto.h>
17 #include <asm/reboot_fixups.h>
18 #include <asm/reboot.h>
19 #include <asm/pci_x86.h>
20 #include <asm/virtext.h>
21 #include <asm/cpu.h>
22 #include <asm/nmi.h>
23 
24 #ifdef CONFIG_X86_32
25 # include <linux/ctype.h>
26 # include <linux/mc146818rtc.h>
27 # include <asm/realmode.h>
28 #else
29 # include <asm/x86_init.h>
30 #endif
31 
32 /*
33  * Power off function, if any
34  */
35 void (*pm_power_off)(void);
36 EXPORT_SYMBOL(pm_power_off);
37 
38 static const struct desc_ptr no_idt = {};
39 static int reboot_mode;
40 enum reboot_type reboot_type = BOOT_ACPI;
41 int reboot_force;
42 
43 /*
44  * This variable is used privately to keep track of whether or not
45  * reboot_type is still set to its default value (i.e., reboot= hasn't
46  * been set on the command line).  This is needed so that we can
47  * suppress DMI scanning for reboot quirks.  Without it, it's
48  * impossible to override a faulty reboot quirk without recompiling.
49  */
50 static int reboot_default = 1;
51 
52 #if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
53 static int reboot_cpu = -1;
54 #endif
55 
56 /*
57  * This is set if we need to go through the 'emergency' path.
58  * When machine_emergency_restart() is called, we may be on
59  * an inconsistent state and won't be able to do a clean cleanup
60  */
61 static int reboot_emergency;
62 
63 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
64 bool port_cf9_safe = false;
65 
66 /*
67  * reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci]
68  * warm   Don't set the cold reboot flag
69  * cold   Set the cold reboot flag
70  * bios   Reboot by jumping through the BIOS (only for X86_32)
71  * smp    Reboot by executing reset on BSP or other CPU (only for X86_32)
72  * triple Force a triple fault (init)
73  * kbd    Use the keyboard controller. cold reset (default)
74  * acpi   Use the RESET_REG in the FADT
75  * efi    Use efi reset_system runtime service
76  * pci    Use the so-called "PCI reset register", CF9
77  * force  Avoid anything that could hang.
78  */
79 static int __init reboot_setup(char *str)
80 {
81 	for (;;) {
82 		/*
83 		 * Having anything passed on the command line via
84 		 * reboot= will cause us to disable DMI checking
85 		 * below.
86 		 */
87 		reboot_default = 0;
88 
89 		switch (*str) {
90 		case 'w':
91 			reboot_mode = 0x1234;
92 			break;
93 
94 		case 'c':
95 			reboot_mode = 0;
96 			break;
97 
98 #ifdef CONFIG_X86_32
99 #ifdef CONFIG_SMP
100 		case 's':
101 			if (isdigit(*(str+1))) {
102 				reboot_cpu = (int) (*(str+1) - '0');
103 				if (isdigit(*(str+2)))
104 					reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
105 			}
106 			/*
107 			 * We will leave sorting out the final value
108 			 * when we are ready to reboot, since we might not
109 			 * have detected BSP APIC ID or smp_num_cpu
110 			 */
111 			break;
112 #endif /* CONFIG_SMP */
113 
114 		case 'b':
115 #endif
116 		case 'a':
117 		case 'k':
118 		case 't':
119 		case 'e':
120 		case 'p':
121 			reboot_type = *str;
122 			break;
123 
124 		case 'f':
125 			reboot_force = 1;
126 			break;
127 		}
128 
129 		str = strchr(str, ',');
130 		if (str)
131 			str++;
132 		else
133 			break;
134 	}
135 	return 1;
136 }
137 
138 __setup("reboot=", reboot_setup);
139 
140 
141 #ifdef CONFIG_X86_32
142 /*
143  * Reboot options and system auto-detection code provided by
144  * Dell Inc. so their systems "just work". :-)
145  */
146 
147 /*
148  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
149  * this quirk makes that automatic.
150  */
151 static int __init set_bios_reboot(const struct dmi_system_id *d)
152 {
153 	if (reboot_type != BOOT_BIOS) {
154 		reboot_type = BOOT_BIOS;
155 		printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
156 	}
157 	return 0;
158 }
159 
160 void machine_real_restart(unsigned int type)
161 {
162 	void (*restart_lowmem)(unsigned int) = (void (*)(unsigned int))
163 		real_mode_header->machine_real_restart_asm;
164 
165 	local_irq_disable();
166 
167 	/*
168 	 * Write zero to CMOS register number 0x0f, which the BIOS POST
169 	 * routine will recognize as telling it to do a proper reboot.  (Well
170 	 * that's what this book in front of me says -- it may only apply to
171 	 * the Phoenix BIOS though, it's not clear).  At the same time,
172 	 * disable NMIs by setting the top bit in the CMOS address register,
173 	 * as we're about to do peculiar things to the CPU.  I'm not sure if
174 	 * `outb_p' is needed instead of just `outb'.  Use it to be on the
175 	 * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
176 	 */
177 	spin_lock(&rtc_lock);
178 	CMOS_WRITE(0x00, 0x8f);
179 	spin_unlock(&rtc_lock);
180 
181 	/*
182 	 * Switch back to the initial page table.
183 	 */
184 	load_cr3(initial_page_table);
185 
186 	/*
187 	 * Write 0x1234 to absolute memory location 0x472.  The BIOS reads
188 	 * this on booting to tell it to "Bypass memory test (also warm
189 	 * boot)".  This seems like a fairly standard thing that gets set by
190 	 * REBOOT.COM programs, and the previous reset routine did this
191 	 * too. */
192 	*((unsigned short *)0x472) = reboot_mode;
193 
194 	/* Jump to the identity-mapped low memory code */
195 	restart_lowmem(type);
196 }
197 #ifdef CONFIG_APM_MODULE
198 EXPORT_SYMBOL(machine_real_restart);
199 #endif
200 
201 #endif /* CONFIG_X86_32 */
202 
203 /*
204  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
205  */
206 static int __init set_pci_reboot(const struct dmi_system_id *d)
207 {
208 	if (reboot_type != BOOT_CF9) {
209 		reboot_type = BOOT_CF9;
210 		printk(KERN_INFO "%s series board detected. "
211 		       "Selecting PCI-method for reboots.\n", d->ident);
212 	}
213 	return 0;
214 }
215 
216 static int __init set_kbd_reboot(const struct dmi_system_id *d)
217 {
218 	if (reboot_type != BOOT_KBD) {
219 		reboot_type = BOOT_KBD;
220 		printk(KERN_INFO "%s series board detected. Selecting KBD-method for reboot.\n", d->ident);
221 	}
222 	return 0;
223 }
224 
225 /*
226  * This is a single dmi_table handling all reboot quirks.  Note that
227  * REBOOT_BIOS is only available for 32bit
228  */
229 static struct dmi_system_id __initdata reboot_dmi_table[] = {
230 #ifdef CONFIG_X86_32
231 	{	/* Handle problems with rebooting on Dell E520's */
232 		.callback = set_bios_reboot,
233 		.ident = "Dell E520",
234 		.matches = {
235 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
236 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
237 		},
238 	},
239 	{	/* Handle problems with rebooting on Dell 1300's */
240 		.callback = set_bios_reboot,
241 		.ident = "Dell PowerEdge 1300",
242 		.matches = {
243 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
244 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
245 		},
246 	},
247 	{	/* Handle problems with rebooting on Dell 300's */
248 		.callback = set_bios_reboot,
249 		.ident = "Dell PowerEdge 300",
250 		.matches = {
251 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
252 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
253 		},
254 	},
255 	{	/* Handle problems with rebooting on Dell Optiplex 745's SFF */
256 		.callback = set_bios_reboot,
257 		.ident = "Dell OptiPlex 745",
258 		.matches = {
259 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
260 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
261 		},
262 	},
263 	{	/* Handle problems with rebooting on Dell Optiplex 745's DFF */
264 		.callback = set_bios_reboot,
265 		.ident = "Dell OptiPlex 745",
266 		.matches = {
267 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
268 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
269 			DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
270 		},
271 	},
272 	{	/* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
273 		.callback = set_bios_reboot,
274 		.ident = "Dell OptiPlex 745",
275 		.matches = {
276 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
277 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
278 			DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
279 		},
280 	},
281 	{	/* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
282 		.callback = set_bios_reboot,
283 		.ident = "Dell OptiPlex 330",
284 		.matches = {
285 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
286 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
287 			DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
288 		},
289 	},
290 	{	/* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
291 		.callback = set_bios_reboot,
292 		.ident = "Dell OptiPlex 360",
293 		.matches = {
294 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
295 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
296 			DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
297 		},
298 	},
299 	{	/* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
300 		.callback = set_bios_reboot,
301 		.ident = "Dell OptiPlex 760",
302 		.matches = {
303 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
304 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
305 			DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
306 		},
307 	},
308 	{	/* Handle problems with rebooting on Dell 2400's */
309 		.callback = set_bios_reboot,
310 		.ident = "Dell PowerEdge 2400",
311 		.matches = {
312 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
313 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
314 		},
315 	},
316 	{	/* Handle problems with rebooting on Dell T5400's */
317 		.callback = set_bios_reboot,
318 		.ident = "Dell Precision T5400",
319 		.matches = {
320 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
321 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
322 		},
323 	},
324 	{	/* Handle problems with rebooting on Dell T7400's */
325 		.callback = set_bios_reboot,
326 		.ident = "Dell Precision T7400",
327 		.matches = {
328 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
329 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
330 		},
331 	},
332 	{	/* Handle problems with rebooting on HP laptops */
333 		.callback = set_bios_reboot,
334 		.ident = "HP Compaq Laptop",
335 		.matches = {
336 			DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
337 			DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
338 		},
339 	},
340 	{	/* Handle problems with rebooting on Dell XPS710 */
341 		.callback = set_bios_reboot,
342 		.ident = "Dell XPS710",
343 		.matches = {
344 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
345 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
346 		},
347 	},
348 	{	/* Handle problems with rebooting on Dell DXP061 */
349 		.callback = set_bios_reboot,
350 		.ident = "Dell DXP061",
351 		.matches = {
352 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
353 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
354 		},
355 	},
356 	{	/* Handle problems with rebooting on Sony VGN-Z540N */
357 		.callback = set_bios_reboot,
358 		.ident = "Sony VGN-Z540N",
359 		.matches = {
360 			DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
361 			DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
362 		},
363 	},
364 	{	/* Handle problems with rebooting on CompuLab SBC-FITPC2 */
365 		.callback = set_bios_reboot,
366 		.ident = "CompuLab SBC-FITPC2",
367 		.matches = {
368 			DMI_MATCH(DMI_SYS_VENDOR, "CompuLab"),
369 			DMI_MATCH(DMI_PRODUCT_NAME, "SBC-FITPC2"),
370 		},
371 	},
372 	{	/* Handle problems with rebooting on ASUS P4S800 */
373 		.callback = set_bios_reboot,
374 		.ident = "ASUS P4S800",
375 		.matches = {
376 			DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
377 			DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
378 		},
379 	},
380 #endif /* CONFIG_X86_32 */
381 
382 	{	/* Handle reboot issue on Acer Aspire one */
383 		.callback = set_kbd_reboot,
384 		.ident = "Acer Aspire One A110",
385 		.matches = {
386 			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
387 			DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
388 		},
389 	},
390 	{	/* Handle problems with rebooting on Apple MacBook5 */
391 		.callback = set_pci_reboot,
392 		.ident = "Apple MacBook5",
393 		.matches = {
394 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
395 			DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
396 		},
397 	},
398 	{	/* Handle problems with rebooting on Apple MacBookPro5 */
399 		.callback = set_pci_reboot,
400 		.ident = "Apple MacBookPro5",
401 		.matches = {
402 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
403 			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
404 		},
405 	},
406 	{	/* Handle problems with rebooting on Apple Macmini3,1 */
407 		.callback = set_pci_reboot,
408 		.ident = "Apple Macmini3,1",
409 		.matches = {
410 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
411 			DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
412 		},
413 	},
414 	{	/* Handle problems with rebooting on the iMac9,1. */
415 		.callback = set_pci_reboot,
416 		.ident = "Apple iMac9,1",
417 		.matches = {
418 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
419 			DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
420 		},
421 	},
422 	{	/* Handle problems with rebooting on the Latitude E6320. */
423 		.callback = set_pci_reboot,
424 		.ident = "Dell Latitude E6320",
425 		.matches = {
426 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
427 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
428 		},
429 	},
430 	{	/* Handle problems with rebooting on the Latitude E5420. */
431 		.callback = set_pci_reboot,
432 		.ident = "Dell Latitude E5420",
433 		.matches = {
434 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
435 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
436 		},
437 	},
438 	{	/* Handle problems with rebooting on the Latitude E6420. */
439 		.callback = set_pci_reboot,
440 		.ident = "Dell Latitude E6420",
441 		.matches = {
442 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
443 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
444 		},
445 	},
446 	{	/* Handle problems with rebooting on the OptiPlex 990. */
447 		.callback = set_pci_reboot,
448 		.ident = "Dell OptiPlex 990",
449 		.matches = {
450 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
451 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
452 		},
453 	},
454 	{	/* Handle problems with rebooting on the Precision M6600. */
455 		.callback = set_pci_reboot,
456 		.ident = "Dell OptiPlex 990",
457 		.matches = {
458 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
459 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
460 		},
461 	},
462 	{ }
463 };
464 
465 static int __init reboot_init(void)
466 {
467 	/*
468 	 * Only do the DMI check if reboot_type hasn't been overridden
469 	 * on the command line
470 	 */
471 	if (reboot_default)
472 		dmi_check_system(reboot_dmi_table);
473 	return 0;
474 }
475 core_initcall(reboot_init);
476 
477 static inline void kb_wait(void)
478 {
479 	int i;
480 
481 	for (i = 0; i < 0x10000; i++) {
482 		if ((inb(0x64) & 0x02) == 0)
483 			break;
484 		udelay(2);
485 	}
486 }
487 
488 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
489 {
490 	cpu_emergency_vmxoff();
491 }
492 
493 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
494 static void emergency_vmx_disable_all(void)
495 {
496 	/* Just make sure we won't change CPUs while doing this */
497 	local_irq_disable();
498 
499 	/*
500 	 * We need to disable VMX on all CPUs before rebooting, otherwise
501 	 * we risk hanging up the machine, because the CPU ignore INIT
502 	 * signals when VMX is enabled.
503 	 *
504 	 * We can't take any locks and we may be on an inconsistent
505 	 * state, so we use NMIs as IPIs to tell the other CPUs to disable
506 	 * VMX and halt.
507 	 *
508 	 * For safety, we will avoid running the nmi_shootdown_cpus()
509 	 * stuff unnecessarily, but we don't have a way to check
510 	 * if other CPUs have VMX enabled. So we will call it only if the
511 	 * CPU we are running on has VMX enabled.
512 	 *
513 	 * We will miss cases where VMX is not enabled on all CPUs. This
514 	 * shouldn't do much harm because KVM always enable VMX on all
515 	 * CPUs anyway. But we can miss it on the small window where KVM
516 	 * is still enabling VMX.
517 	 */
518 	if (cpu_has_vmx() && cpu_vmx_enabled()) {
519 		/* Disable VMX on this CPU. */
520 		cpu_vmxoff();
521 
522 		/* Halt and disable VMX on the other CPUs */
523 		nmi_shootdown_cpus(vmxoff_nmi);
524 
525 	}
526 }
527 
528 
529 void __attribute__((weak)) mach_reboot_fixups(void)
530 {
531 }
532 
533 /*
534  * Windows compatible x86 hardware expects the following on reboot:
535  *
536  * 1) If the FADT has the ACPI reboot register flag set, try it
537  * 2) If still alive, write to the keyboard controller
538  * 3) If still alive, write to the ACPI reboot register again
539  * 4) If still alive, write to the keyboard controller again
540  *
541  * If the machine is still alive at this stage, it gives up. We default to
542  * following the same pattern, except that if we're still alive after (4) we'll
543  * try to force a triple fault and then cycle between hitting the keyboard
544  * controller and doing that
545  */
546 static void native_machine_emergency_restart(void)
547 {
548 	int i;
549 	int attempt = 0;
550 	int orig_reboot_type = reboot_type;
551 
552 	if (reboot_emergency)
553 		emergency_vmx_disable_all();
554 
555 	tboot_shutdown(TB_SHUTDOWN_REBOOT);
556 
557 	/* Tell the BIOS if we want cold or warm reboot */
558 	*((unsigned short *)__va(0x472)) = reboot_mode;
559 
560 	for (;;) {
561 		/* Could also try the reset bit in the Hammer NB */
562 		switch (reboot_type) {
563 		case BOOT_KBD:
564 			mach_reboot_fixups(); /* For board specific fixups */
565 
566 			for (i = 0; i < 10; i++) {
567 				kb_wait();
568 				udelay(50);
569 				outb(0xfe, 0x64); /* Pulse reset low */
570 				udelay(50);
571 			}
572 			if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
573 				attempt = 1;
574 				reboot_type = BOOT_ACPI;
575 			} else {
576 				reboot_type = BOOT_TRIPLE;
577 			}
578 			break;
579 
580 		case BOOT_TRIPLE:
581 			load_idt(&no_idt);
582 			__asm__ __volatile__("int3");
583 
584 			reboot_type = BOOT_KBD;
585 			break;
586 
587 #ifdef CONFIG_X86_32
588 		case BOOT_BIOS:
589 			machine_real_restart(MRR_BIOS);
590 
591 			reboot_type = BOOT_KBD;
592 			break;
593 #endif
594 
595 		case BOOT_ACPI:
596 			acpi_reboot();
597 			reboot_type = BOOT_KBD;
598 			break;
599 
600 		case BOOT_EFI:
601 			if (efi_enabled)
602 				efi.reset_system(reboot_mode ?
603 						 EFI_RESET_WARM :
604 						 EFI_RESET_COLD,
605 						 EFI_SUCCESS, 0, NULL);
606 			reboot_type = BOOT_KBD;
607 			break;
608 
609 		case BOOT_CF9:
610 			port_cf9_safe = true;
611 			/* Fall through */
612 
613 		case BOOT_CF9_COND:
614 			if (port_cf9_safe) {
615 				u8 cf9 = inb(0xcf9) & ~6;
616 				outb(cf9|2, 0xcf9); /* Request hard reset */
617 				udelay(50);
618 				outb(cf9|6, 0xcf9); /* Actually do the reset */
619 				udelay(50);
620 			}
621 			reboot_type = BOOT_KBD;
622 			break;
623 		}
624 	}
625 }
626 
627 void native_machine_shutdown(void)
628 {
629 	/* Stop the cpus and apics */
630 #ifdef CONFIG_SMP
631 
632 	/* The boot cpu is always logical cpu 0 */
633 	int reboot_cpu_id = 0;
634 
635 #ifdef CONFIG_X86_32
636 	/* See if there has been given a command line override */
637 	if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
638 		cpu_online(reboot_cpu))
639 		reboot_cpu_id = reboot_cpu;
640 #endif
641 
642 	/* Make certain the cpu I'm about to reboot on is online */
643 	if (!cpu_online(reboot_cpu_id))
644 		reboot_cpu_id = smp_processor_id();
645 
646 	/* Make certain I only run on the appropriate processor */
647 	set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
648 
649 	/*
650 	 * O.K Now that I'm on the appropriate processor, stop all of the
651 	 * others. Also disable the local irq to not receive the per-cpu
652 	 * timer interrupt which may trigger scheduler's load balance.
653 	 */
654 	local_irq_disable();
655 	stop_other_cpus();
656 #endif
657 
658 	lapic_shutdown();
659 
660 #ifdef CONFIG_X86_IO_APIC
661 	disable_IO_APIC();
662 #endif
663 
664 #ifdef CONFIG_HPET_TIMER
665 	hpet_disable();
666 #endif
667 
668 #ifdef CONFIG_X86_64
669 	x86_platform.iommu_shutdown();
670 #endif
671 }
672 
673 static void __machine_emergency_restart(int emergency)
674 {
675 	reboot_emergency = emergency;
676 	machine_ops.emergency_restart();
677 }
678 
679 static void native_machine_restart(char *__unused)
680 {
681 	printk("machine restart\n");
682 
683 	if (!reboot_force)
684 		machine_shutdown();
685 	__machine_emergency_restart(0);
686 }
687 
688 static void native_machine_halt(void)
689 {
690 	/* Stop other cpus and apics */
691 	machine_shutdown();
692 
693 	tboot_shutdown(TB_SHUTDOWN_HALT);
694 
695 	stop_this_cpu(NULL);
696 }
697 
698 static void native_machine_power_off(void)
699 {
700 	if (pm_power_off) {
701 		if (!reboot_force)
702 			machine_shutdown();
703 		pm_power_off();
704 	}
705 	/* A fallback in case there is no PM info available */
706 	tboot_shutdown(TB_SHUTDOWN_HALT);
707 }
708 
709 struct machine_ops machine_ops = {
710 	.power_off = native_machine_power_off,
711 	.shutdown = native_machine_shutdown,
712 	.emergency_restart = native_machine_emergency_restart,
713 	.restart = native_machine_restart,
714 	.halt = native_machine_halt,
715 #ifdef CONFIG_KEXEC
716 	.crash_shutdown = native_machine_crash_shutdown,
717 #endif
718 };
719 
720 void machine_power_off(void)
721 {
722 	machine_ops.power_off();
723 }
724 
725 void machine_shutdown(void)
726 {
727 	machine_ops.shutdown();
728 }
729 
730 void machine_emergency_restart(void)
731 {
732 	__machine_emergency_restart(1);
733 }
734 
735 void machine_restart(char *cmd)
736 {
737 	machine_ops.restart(cmd);
738 }
739 
740 void machine_halt(void)
741 {
742 	machine_ops.halt();
743 }
744 
745 #ifdef CONFIG_KEXEC
746 void machine_crash_shutdown(struct pt_regs *regs)
747 {
748 	machine_ops.crash_shutdown(regs);
749 }
750 #endif
751 
752 
753 #if defined(CONFIG_SMP)
754 
755 /* This keeps a track of which one is crashing cpu. */
756 static int crashing_cpu;
757 static nmi_shootdown_cb shootdown_callback;
758 
759 static atomic_t waiting_for_crash_ipi;
760 
761 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
762 {
763 	int cpu;
764 
765 	cpu = raw_smp_processor_id();
766 
767 	/*
768 	 * Don't do anything if this handler is invoked on crashing cpu.
769 	 * Otherwise, system will completely hang. Crashing cpu can get
770 	 * an NMI if system was initially booted with nmi_watchdog parameter.
771 	 */
772 	if (cpu == crashing_cpu)
773 		return NMI_HANDLED;
774 	local_irq_disable();
775 
776 	shootdown_callback(cpu, regs);
777 
778 	atomic_dec(&waiting_for_crash_ipi);
779 	/* Assume hlt works */
780 	halt();
781 	for (;;)
782 		cpu_relax();
783 
784 	return NMI_HANDLED;
785 }
786 
787 static void smp_send_nmi_allbutself(void)
788 {
789 	apic->send_IPI_allbutself(NMI_VECTOR);
790 }
791 
792 /*
793  * Halt all other CPUs, calling the specified function on each of them
794  *
795  * This function can be used to halt all other CPUs on crash
796  * or emergency reboot time. The function passed as parameter
797  * will be called inside a NMI handler on all CPUs.
798  */
799 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
800 {
801 	unsigned long msecs;
802 	local_irq_disable();
803 
804 	/* Make a note of crashing cpu. Will be used in NMI callback. */
805 	crashing_cpu = safe_smp_processor_id();
806 
807 	shootdown_callback = callback;
808 
809 	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
810 	/* Would it be better to replace the trap vector here? */
811 	if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
812 				 NMI_FLAG_FIRST, "crash"))
813 		return;		/* Return what? */
814 	/*
815 	 * Ensure the new callback function is set before sending
816 	 * out the NMI
817 	 */
818 	wmb();
819 
820 	smp_send_nmi_allbutself();
821 
822 	msecs = 1000; /* Wait at most a second for the other cpus to stop */
823 	while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
824 		mdelay(1);
825 		msecs--;
826 	}
827 
828 	/* Leave the nmi callback set */
829 }
830 #else /* !CONFIG_SMP */
831 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
832 {
833 	/* No other CPUs to shoot down */
834 }
835 #endif
836