xref: /linux/arch/x86/kernel/reboot.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
1 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
2 
3 #include <linux/module.h>
4 #include <linux/reboot.h>
5 #include <linux/init.h>
6 #include <linux/pm.h>
7 #include <linux/efi.h>
8 #include <linux/dmi.h>
9 #include <linux/sched.h>
10 #include <linux/tboot.h>
11 #include <linux/delay.h>
12 #include <acpi/reboot.h>
13 #include <asm/io.h>
14 #include <asm/apic.h>
15 #include <asm/desc.h>
16 #include <asm/hpet.h>
17 #include <asm/pgtable.h>
18 #include <asm/proto.h>
19 #include <asm/reboot_fixups.h>
20 #include <asm/reboot.h>
21 #include <asm/pci_x86.h>
22 #include <asm/virtext.h>
23 #include <asm/cpu.h>
24 #include <asm/nmi.h>
25 #include <asm/smp.h>
26 
27 #include <linux/ctype.h>
28 #include <linux/mc146818rtc.h>
29 #include <asm/realmode.h>
30 #include <asm/x86_init.h>
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 #ifdef 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
71  * smp    Reboot by executing reset on BSP or other CPU
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_SMP
99 		case 's':
100 			if (isdigit(*(str+1))) {
101 				reboot_cpu = (int) (*(str+1) - '0');
102 				if (isdigit(*(str+2)))
103 					reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
104 			}
105 			/*
106 			 * We will leave sorting out the final value
107 			 * when we are ready to reboot, since we might not
108 			 * have detected BSP APIC ID or smp_num_cpu
109 			 */
110 			break;
111 #endif /* CONFIG_SMP */
112 
113 		case 'b':
114 		case 'a':
115 		case 'k':
116 		case 't':
117 		case 'e':
118 		case 'p':
119 			reboot_type = *str;
120 			break;
121 
122 		case 'f':
123 			reboot_force = 1;
124 			break;
125 		}
126 
127 		str = strchr(str, ',');
128 		if (str)
129 			str++;
130 		else
131 			break;
132 	}
133 	return 1;
134 }
135 
136 __setup("reboot=", reboot_setup);
137 
138 
139 /*
140  * Reboot options and system auto-detection code provided by
141  * Dell Inc. so their systems "just work". :-)
142  */
143 
144 /*
145  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
146  * this quirk makes that automatic.
147  */
148 static int __init set_bios_reboot(const struct dmi_system_id *d)
149 {
150 	if (reboot_type != BOOT_BIOS) {
151 		reboot_type = BOOT_BIOS;
152 		pr_info("%s series board detected. Selecting %s-method for reboots.\n",
153 			"BIOS", d->ident);
154 	}
155 	return 0;
156 }
157 
158 void __noreturn machine_real_restart(unsigned int type)
159 {
160 	local_irq_disable();
161 
162 	/*
163 	 * Write zero to CMOS register number 0x0f, which the BIOS POST
164 	 * routine will recognize as telling it to do a proper reboot.  (Well
165 	 * that's what this book in front of me says -- it may only apply to
166 	 * the Phoenix BIOS though, it's not clear).  At the same time,
167 	 * disable NMIs by setting the top bit in the CMOS address register,
168 	 * as we're about to do peculiar things to the CPU.  I'm not sure if
169 	 * `outb_p' is needed instead of just `outb'.  Use it to be on the
170 	 * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
171 	 */
172 	spin_lock(&rtc_lock);
173 	CMOS_WRITE(0x00, 0x8f);
174 	spin_unlock(&rtc_lock);
175 
176 	/*
177 	 * Switch back to the initial page table.
178 	 */
179 #ifdef CONFIG_X86_32
180 	load_cr3(initial_page_table);
181 #else
182 	write_cr3(real_mode_header->trampoline_pgd);
183 #endif
184 
185 	/* Jump to the identity-mapped low memory code */
186 #ifdef CONFIG_X86_32
187 	asm volatile("jmpl *%0" : :
188 		     "rm" (real_mode_header->machine_real_restart_asm),
189 		     "a" (type));
190 #else
191 	asm volatile("ljmpl *%0" : :
192 		     "m" (real_mode_header->machine_real_restart_asm),
193 		     "D" (type));
194 #endif
195 	unreachable();
196 }
197 #ifdef CONFIG_APM_MODULE
198 EXPORT_SYMBOL(machine_real_restart);
199 #endif
200 
201 /*
202  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
203  */
204 static int __init set_pci_reboot(const struct dmi_system_id *d)
205 {
206 	if (reboot_type != BOOT_CF9) {
207 		reboot_type = BOOT_CF9;
208 		pr_info("%s series board detected. Selecting %s-method for reboots.\n",
209 			"PCI", d->ident);
210 	}
211 	return 0;
212 }
213 
214 static int __init set_kbd_reboot(const struct dmi_system_id *d)
215 {
216 	if (reboot_type != BOOT_KBD) {
217 		reboot_type = BOOT_KBD;
218 		pr_info("%s series board detected. Selecting %s-method for reboot.\n",
219 			"KBD", d->ident);
220 	}
221 	return 0;
222 }
223 
224 /*
225  * This is a single dmi_table handling all reboot quirks.
226  */
227 static struct dmi_system_id __initdata reboot_dmi_table[] = {
228 	{	/* Handle problems with rebooting on Dell E520's */
229 		.callback = set_bios_reboot,
230 		.ident = "Dell E520",
231 		.matches = {
232 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
233 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
234 		},
235 	},
236 	{	/* Handle problems with rebooting on Dell 1300's */
237 		.callback = set_bios_reboot,
238 		.ident = "Dell PowerEdge 1300",
239 		.matches = {
240 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
241 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
242 		},
243 	},
244 	{	/* Handle problems with rebooting on Dell 300's */
245 		.callback = set_bios_reboot,
246 		.ident = "Dell PowerEdge 300",
247 		.matches = {
248 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
249 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
250 		},
251 	},
252 	{	/* Handle problems with rebooting on Dell Optiplex 745's SFF */
253 		.callback = set_bios_reboot,
254 		.ident = "Dell OptiPlex 745",
255 		.matches = {
256 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
257 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
258 		},
259 	},
260 	{	/* Handle problems with rebooting on Dell Optiplex 745's DFF */
261 		.callback = set_bios_reboot,
262 		.ident = "Dell OptiPlex 745",
263 		.matches = {
264 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
265 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
266 			DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
267 		},
268 	},
269 	{	/* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
270 		.callback = set_bios_reboot,
271 		.ident = "Dell OptiPlex 745",
272 		.matches = {
273 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
274 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
275 			DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
276 		},
277 	},
278 	{	/* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
279 		.callback = set_bios_reboot,
280 		.ident = "Dell OptiPlex 330",
281 		.matches = {
282 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
283 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
284 			DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
285 		},
286 	},
287 	{	/* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
288 		.callback = set_bios_reboot,
289 		.ident = "Dell OptiPlex 360",
290 		.matches = {
291 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
292 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
293 			DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
294 		},
295 	},
296 	{	/* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
297 		.callback = set_bios_reboot,
298 		.ident = "Dell OptiPlex 760",
299 		.matches = {
300 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
301 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
302 			DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
303 		},
304 	},
305 	{	/* Handle problems with rebooting on Dell 2400's */
306 		.callback = set_bios_reboot,
307 		.ident = "Dell PowerEdge 2400",
308 		.matches = {
309 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
310 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
311 		},
312 	},
313 	{	/* Handle problems with rebooting on Dell T5400's */
314 		.callback = set_bios_reboot,
315 		.ident = "Dell Precision T5400",
316 		.matches = {
317 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
318 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
319 		},
320 	},
321 	{	/* Handle problems with rebooting on Dell T7400's */
322 		.callback = set_bios_reboot,
323 		.ident = "Dell Precision T7400",
324 		.matches = {
325 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
326 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
327 		},
328 	},
329 	{	/* Handle problems with rebooting on HP laptops */
330 		.callback = set_bios_reboot,
331 		.ident = "HP Compaq Laptop",
332 		.matches = {
333 			DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
334 			DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
335 		},
336 	},
337 	{	/* Handle problems with rebooting on Dell XPS710 */
338 		.callback = set_bios_reboot,
339 		.ident = "Dell XPS710",
340 		.matches = {
341 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
342 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
343 		},
344 	},
345 	{	/* Handle problems with rebooting on Dell DXP061 */
346 		.callback = set_bios_reboot,
347 		.ident = "Dell DXP061",
348 		.matches = {
349 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
350 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
351 		},
352 	},
353 	{	/* Handle problems with rebooting on Sony VGN-Z540N */
354 		.callback = set_bios_reboot,
355 		.ident = "Sony VGN-Z540N",
356 		.matches = {
357 			DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
358 			DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
359 		},
360 	},
361 	{	/* Handle problems with rebooting on ASUS P4S800 */
362 		.callback = set_bios_reboot,
363 		.ident = "ASUS P4S800",
364 		.matches = {
365 			DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
366 			DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
367 		},
368 	},
369 
370 	{	/* Handle reboot issue on Acer Aspire one */
371 		.callback = set_kbd_reboot,
372 		.ident = "Acer Aspire One A110",
373 		.matches = {
374 			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
375 			DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
376 		},
377 	},
378 	{	/* Handle problems with rebooting on Apple MacBook5 */
379 		.callback = set_pci_reboot,
380 		.ident = "Apple MacBook5",
381 		.matches = {
382 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
383 			DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
384 		},
385 	},
386 	{	/* Handle problems with rebooting on Apple MacBookPro5 */
387 		.callback = set_pci_reboot,
388 		.ident = "Apple MacBookPro5",
389 		.matches = {
390 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
391 			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
392 		},
393 	},
394 	{	/* Handle problems with rebooting on Apple Macmini3,1 */
395 		.callback = set_pci_reboot,
396 		.ident = "Apple Macmini3,1",
397 		.matches = {
398 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
399 			DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
400 		},
401 	},
402 	{	/* Handle problems with rebooting on the iMac9,1. */
403 		.callback = set_pci_reboot,
404 		.ident = "Apple iMac9,1",
405 		.matches = {
406 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
407 			DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
408 		},
409 	},
410 	{	/* Handle problems with rebooting on the Latitude E6320. */
411 		.callback = set_pci_reboot,
412 		.ident = "Dell Latitude E6320",
413 		.matches = {
414 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
415 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
416 		},
417 	},
418 	{	/* Handle problems with rebooting on the Latitude E5420. */
419 		.callback = set_pci_reboot,
420 		.ident = "Dell Latitude E5420",
421 		.matches = {
422 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
423 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
424 		},
425 	},
426 	{	/* Handle problems with rebooting on the Latitude E6420. */
427 		.callback = set_pci_reboot,
428 		.ident = "Dell Latitude E6420",
429 		.matches = {
430 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
431 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
432 		},
433 	},
434 	{	/* Handle problems with rebooting on the OptiPlex 990. */
435 		.callback = set_pci_reboot,
436 		.ident = "Dell OptiPlex 990",
437 		.matches = {
438 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
439 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
440 		},
441 	},
442 	{	/* Handle problems with rebooting on the Precision M6600. */
443 		.callback = set_pci_reboot,
444 		.ident = "Dell OptiPlex 990",
445 		.matches = {
446 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
447 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
448 		},
449 	},
450 	{ }
451 };
452 
453 static int __init reboot_init(void)
454 {
455 	/*
456 	 * Only do the DMI check if reboot_type hasn't been overridden
457 	 * on the command line
458 	 */
459 	if (reboot_default)
460 		dmi_check_system(reboot_dmi_table);
461 	return 0;
462 }
463 core_initcall(reboot_init);
464 
465 static inline void kb_wait(void)
466 {
467 	int i;
468 
469 	for (i = 0; i < 0x10000; i++) {
470 		if ((inb(0x64) & 0x02) == 0)
471 			break;
472 		udelay(2);
473 	}
474 }
475 
476 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
477 {
478 	cpu_emergency_vmxoff();
479 }
480 
481 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
482 static void emergency_vmx_disable_all(void)
483 {
484 	/* Just make sure we won't change CPUs while doing this */
485 	local_irq_disable();
486 
487 	/*
488 	 * We need to disable VMX on all CPUs before rebooting, otherwise
489 	 * we risk hanging up the machine, because the CPU ignore INIT
490 	 * signals when VMX is enabled.
491 	 *
492 	 * We can't take any locks and we may be on an inconsistent
493 	 * state, so we use NMIs as IPIs to tell the other CPUs to disable
494 	 * VMX and halt.
495 	 *
496 	 * For safety, we will avoid running the nmi_shootdown_cpus()
497 	 * stuff unnecessarily, but we don't have a way to check
498 	 * if other CPUs have VMX enabled. So we will call it only if the
499 	 * CPU we are running on has VMX enabled.
500 	 *
501 	 * We will miss cases where VMX is not enabled on all CPUs. This
502 	 * shouldn't do much harm because KVM always enable VMX on all
503 	 * CPUs anyway. But we can miss it on the small window where KVM
504 	 * is still enabling VMX.
505 	 */
506 	if (cpu_has_vmx() && cpu_vmx_enabled()) {
507 		/* Disable VMX on this CPU. */
508 		cpu_vmxoff();
509 
510 		/* Halt and disable VMX on the other CPUs */
511 		nmi_shootdown_cpus(vmxoff_nmi);
512 
513 	}
514 }
515 
516 
517 void __attribute__((weak)) mach_reboot_fixups(void)
518 {
519 }
520 
521 /*
522  * Windows compatible x86 hardware expects the following on reboot:
523  *
524  * 1) If the FADT has the ACPI reboot register flag set, try it
525  * 2) If still alive, write to the keyboard controller
526  * 3) If still alive, write to the ACPI reboot register again
527  * 4) If still alive, write to the keyboard controller again
528  *
529  * If the machine is still alive at this stage, it gives up. We default to
530  * following the same pattern, except that if we're still alive after (4) we'll
531  * try to force a triple fault and then cycle between hitting the keyboard
532  * controller and doing that
533  */
534 static void native_machine_emergency_restart(void)
535 {
536 	int i;
537 	int attempt = 0;
538 	int orig_reboot_type = reboot_type;
539 
540 	if (reboot_emergency)
541 		emergency_vmx_disable_all();
542 
543 	tboot_shutdown(TB_SHUTDOWN_REBOOT);
544 
545 	/* Tell the BIOS if we want cold or warm reboot */
546 	*((unsigned short *)__va(0x472)) = reboot_mode;
547 
548 	for (;;) {
549 		/* Could also try the reset bit in the Hammer NB */
550 		switch (reboot_type) {
551 		case BOOT_KBD:
552 			mach_reboot_fixups(); /* For board specific fixups */
553 
554 			for (i = 0; i < 10; i++) {
555 				kb_wait();
556 				udelay(50);
557 				outb(0xfe, 0x64); /* Pulse reset low */
558 				udelay(50);
559 			}
560 			if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
561 				attempt = 1;
562 				reboot_type = BOOT_ACPI;
563 			} else {
564 				reboot_type = BOOT_TRIPLE;
565 			}
566 			break;
567 
568 		case BOOT_TRIPLE:
569 			load_idt(&no_idt);
570 			__asm__ __volatile__("int3");
571 
572 			reboot_type = BOOT_KBD;
573 			break;
574 
575 		case BOOT_BIOS:
576 			machine_real_restart(MRR_BIOS);
577 
578 			reboot_type = BOOT_KBD;
579 			break;
580 
581 		case BOOT_ACPI:
582 			acpi_reboot();
583 			reboot_type = BOOT_KBD;
584 			break;
585 
586 		case BOOT_EFI:
587 			if (efi_enabled)
588 				efi.reset_system(reboot_mode ?
589 						 EFI_RESET_WARM :
590 						 EFI_RESET_COLD,
591 						 EFI_SUCCESS, 0, NULL);
592 			reboot_type = BOOT_KBD;
593 			break;
594 
595 		case BOOT_CF9:
596 			port_cf9_safe = true;
597 			/* Fall through */
598 
599 		case BOOT_CF9_COND:
600 			if (port_cf9_safe) {
601 				u8 cf9 = inb(0xcf9) & ~6;
602 				outb(cf9|2, 0xcf9); /* Request hard reset */
603 				udelay(50);
604 				outb(cf9|6, 0xcf9); /* Actually do the reset */
605 				udelay(50);
606 			}
607 			reboot_type = BOOT_KBD;
608 			break;
609 		}
610 	}
611 }
612 
613 void native_machine_shutdown(void)
614 {
615 	/* Stop the cpus and apics */
616 #ifdef CONFIG_SMP
617 
618 	/* The boot cpu is always logical cpu 0 */
619 	int reboot_cpu_id = 0;
620 
621 	/* See if there has been given a command line override */
622 	if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
623 		cpu_online(reboot_cpu))
624 		reboot_cpu_id = reboot_cpu;
625 
626 	/* Make certain the cpu I'm about to reboot on is online */
627 	if (!cpu_online(reboot_cpu_id))
628 		reboot_cpu_id = smp_processor_id();
629 
630 	/* Make certain I only run on the appropriate processor */
631 	set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
632 
633 	/*
634 	 * O.K Now that I'm on the appropriate processor, stop all of the
635 	 * others. Also disable the local irq to not receive the per-cpu
636 	 * timer interrupt which may trigger scheduler's load balance.
637 	 */
638 	local_irq_disable();
639 	stop_other_cpus();
640 #endif
641 
642 	lapic_shutdown();
643 
644 #ifdef CONFIG_X86_IO_APIC
645 	disable_IO_APIC();
646 #endif
647 
648 #ifdef CONFIG_HPET_TIMER
649 	hpet_disable();
650 #endif
651 
652 #ifdef CONFIG_X86_64
653 	x86_platform.iommu_shutdown();
654 #endif
655 }
656 
657 static void __machine_emergency_restart(int emergency)
658 {
659 	reboot_emergency = emergency;
660 	machine_ops.emergency_restart();
661 }
662 
663 static void native_machine_restart(char *__unused)
664 {
665 	pr_notice("machine restart\n");
666 
667 	if (!reboot_force)
668 		machine_shutdown();
669 	__machine_emergency_restart(0);
670 }
671 
672 static void native_machine_halt(void)
673 {
674 	/* Stop other cpus and apics */
675 	machine_shutdown();
676 
677 	tboot_shutdown(TB_SHUTDOWN_HALT);
678 
679 	stop_this_cpu(NULL);
680 }
681 
682 static void native_machine_power_off(void)
683 {
684 	if (pm_power_off) {
685 		if (!reboot_force)
686 			machine_shutdown();
687 		pm_power_off();
688 	}
689 	/* A fallback in case there is no PM info available */
690 	tboot_shutdown(TB_SHUTDOWN_HALT);
691 }
692 
693 struct machine_ops machine_ops = {
694 	.power_off = native_machine_power_off,
695 	.shutdown = native_machine_shutdown,
696 	.emergency_restart = native_machine_emergency_restart,
697 	.restart = native_machine_restart,
698 	.halt = native_machine_halt,
699 #ifdef CONFIG_KEXEC
700 	.crash_shutdown = native_machine_crash_shutdown,
701 #endif
702 };
703 
704 void machine_power_off(void)
705 {
706 	machine_ops.power_off();
707 }
708 
709 void machine_shutdown(void)
710 {
711 	machine_ops.shutdown();
712 }
713 
714 void machine_emergency_restart(void)
715 {
716 	__machine_emergency_restart(1);
717 }
718 
719 void machine_restart(char *cmd)
720 {
721 	machine_ops.restart(cmd);
722 }
723 
724 void machine_halt(void)
725 {
726 	machine_ops.halt();
727 }
728 
729 #ifdef CONFIG_KEXEC
730 void machine_crash_shutdown(struct pt_regs *regs)
731 {
732 	machine_ops.crash_shutdown(regs);
733 }
734 #endif
735 
736 
737 #if defined(CONFIG_SMP)
738 
739 /* This keeps a track of which one is crashing cpu. */
740 static int crashing_cpu;
741 static nmi_shootdown_cb shootdown_callback;
742 
743 static atomic_t waiting_for_crash_ipi;
744 
745 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
746 {
747 	int cpu;
748 
749 	cpu = raw_smp_processor_id();
750 
751 	/*
752 	 * Don't do anything if this handler is invoked on crashing cpu.
753 	 * Otherwise, system will completely hang. Crashing cpu can get
754 	 * an NMI if system was initially booted with nmi_watchdog parameter.
755 	 */
756 	if (cpu == crashing_cpu)
757 		return NMI_HANDLED;
758 	local_irq_disable();
759 
760 	shootdown_callback(cpu, regs);
761 
762 	atomic_dec(&waiting_for_crash_ipi);
763 	/* Assume hlt works */
764 	halt();
765 	for (;;)
766 		cpu_relax();
767 
768 	return NMI_HANDLED;
769 }
770 
771 static void smp_send_nmi_allbutself(void)
772 {
773 	apic->send_IPI_allbutself(NMI_VECTOR);
774 }
775 
776 /*
777  * Halt all other CPUs, calling the specified function on each of them
778  *
779  * This function can be used to halt all other CPUs on crash
780  * or emergency reboot time. The function passed as parameter
781  * will be called inside a NMI handler on all CPUs.
782  */
783 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
784 {
785 	unsigned long msecs;
786 	local_irq_disable();
787 
788 	/* Make a note of crashing cpu. Will be used in NMI callback. */
789 	crashing_cpu = safe_smp_processor_id();
790 
791 	shootdown_callback = callback;
792 
793 	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
794 	/* Would it be better to replace the trap vector here? */
795 	if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
796 				 NMI_FLAG_FIRST, "crash"))
797 		return;		/* Return what? */
798 	/*
799 	 * Ensure the new callback function is set before sending
800 	 * out the NMI
801 	 */
802 	wmb();
803 
804 	smp_send_nmi_allbutself();
805 
806 	msecs = 1000; /* Wait at most a second for the other cpus to stop */
807 	while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
808 		mdelay(1);
809 		msecs--;
810 	}
811 
812 	/* Leave the nmi callback set */
813 }
814 #else /* !CONFIG_SMP */
815 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
816 {
817 	/* No other CPUs to shoot down */
818 }
819 #endif
820