xref: /openbmc/linux/arch/x86/kernel/reboot.c (revision b34e08d5)
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 
40 /*
41  * This is set if we need to go through the 'emergency' path.
42  * When machine_emergency_restart() is called, we may be on
43  * an inconsistent state and won't be able to do a clean cleanup
44  */
45 static int reboot_emergency;
46 
47 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
48 bool port_cf9_safe = false;
49 
50 /*
51  * Reboot options and system auto-detection code provided by
52  * Dell Inc. so their systems "just work". :-)
53  */
54 
55 /*
56  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
57  * this quirk makes that automatic.
58  */
59 static int __init set_bios_reboot(const struct dmi_system_id *d)
60 {
61 	if (reboot_type != BOOT_BIOS) {
62 		reboot_type = BOOT_BIOS;
63 		pr_info("%s series board detected. Selecting %s-method for reboots.\n",
64 			d->ident, "BIOS");
65 	}
66 	return 0;
67 }
68 
69 void __noreturn machine_real_restart(unsigned int type)
70 {
71 	local_irq_disable();
72 
73 	/*
74 	 * Write zero to CMOS register number 0x0f, which the BIOS POST
75 	 * routine will recognize as telling it to do a proper reboot.  (Well
76 	 * that's what this book in front of me says -- it may only apply to
77 	 * the Phoenix BIOS though, it's not clear).  At the same time,
78 	 * disable NMIs by setting the top bit in the CMOS address register,
79 	 * as we're about to do peculiar things to the CPU.  I'm not sure if
80 	 * `outb_p' is needed instead of just `outb'.  Use it to be on the
81 	 * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
82 	 */
83 	spin_lock(&rtc_lock);
84 	CMOS_WRITE(0x00, 0x8f);
85 	spin_unlock(&rtc_lock);
86 
87 	/*
88 	 * Switch back to the initial page table.
89 	 */
90 #ifdef CONFIG_X86_32
91 	load_cr3(initial_page_table);
92 #else
93 	write_cr3(real_mode_header->trampoline_pgd);
94 #endif
95 
96 	/* Jump to the identity-mapped low memory code */
97 #ifdef CONFIG_X86_32
98 	asm volatile("jmpl *%0" : :
99 		     "rm" (real_mode_header->machine_real_restart_asm),
100 		     "a" (type));
101 #else
102 	asm volatile("ljmpl *%0" : :
103 		     "m" (real_mode_header->machine_real_restart_asm),
104 		     "D" (type));
105 #endif
106 	unreachable();
107 }
108 #ifdef CONFIG_APM_MODULE
109 EXPORT_SYMBOL(machine_real_restart);
110 #endif
111 
112 /*
113  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
114  */
115 static int __init set_pci_reboot(const struct dmi_system_id *d)
116 {
117 	if (reboot_type != BOOT_CF9) {
118 		reboot_type = BOOT_CF9;
119 		pr_info("%s series board detected. Selecting %s-method for reboots.\n",
120 			d->ident, "PCI");
121 	}
122 	return 0;
123 }
124 
125 static int __init set_kbd_reboot(const struct dmi_system_id *d)
126 {
127 	if (reboot_type != BOOT_KBD) {
128 		reboot_type = BOOT_KBD;
129 		pr_info("%s series board detected. Selecting %s-method for reboot.\n",
130 			d->ident, "KBD");
131 	}
132 	return 0;
133 }
134 
135 /*
136  * This is a single dmi_table handling all reboot quirks.
137  */
138 static struct dmi_system_id __initdata reboot_dmi_table[] = {
139 
140 	/* Acer */
141 	{	/* Handle reboot issue on Acer Aspire one */
142 		.callback = set_kbd_reboot,
143 		.ident = "Acer Aspire One A110",
144 		.matches = {
145 			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
146 			DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
147 		},
148 	},
149 
150 	/* Apple */
151 	{	/* Handle problems with rebooting on Apple MacBook5 */
152 		.callback = set_pci_reboot,
153 		.ident = "Apple MacBook5",
154 		.matches = {
155 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
156 			DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
157 		},
158 	},
159 	{	/* Handle problems with rebooting on Apple MacBookPro5 */
160 		.callback = set_pci_reboot,
161 		.ident = "Apple MacBookPro5",
162 		.matches = {
163 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
164 			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
165 		},
166 	},
167 	{	/* Handle problems with rebooting on Apple Macmini3,1 */
168 		.callback = set_pci_reboot,
169 		.ident = "Apple Macmini3,1",
170 		.matches = {
171 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
172 			DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
173 		},
174 	},
175 	{	/* Handle problems with rebooting on the iMac9,1. */
176 		.callback = set_pci_reboot,
177 		.ident = "Apple iMac9,1",
178 		.matches = {
179 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
180 			DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
181 		},
182 	},
183 
184 	/* ASUS */
185 	{	/* Handle problems with rebooting on ASUS P4S800 */
186 		.callback = set_bios_reboot,
187 		.ident = "ASUS P4S800",
188 		.matches = {
189 			DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
190 			DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
191 		},
192 	},
193 
194 	/* Dell */
195 	{	/* Handle problems with rebooting on Dell DXP061 */
196 		.callback = set_bios_reboot,
197 		.ident = "Dell DXP061",
198 		.matches = {
199 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
200 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
201 		},
202 	},
203 	{	/* Handle problems with rebooting on Dell E520's */
204 		.callback = set_bios_reboot,
205 		.ident = "Dell E520",
206 		.matches = {
207 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
208 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
209 		},
210 	},
211 	{	/* Handle problems with rebooting on the Latitude E5410. */
212 		.callback = set_pci_reboot,
213 		.ident = "Dell Latitude E5410",
214 		.matches = {
215 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
216 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
217 		},
218 	},
219 	{	/* Handle problems with rebooting on the Latitude E5420. */
220 		.callback = set_pci_reboot,
221 		.ident = "Dell Latitude E5420",
222 		.matches = {
223 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
224 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
225 		},
226 	},
227 	{	/* Handle problems with rebooting on the Latitude E6320. */
228 		.callback = set_pci_reboot,
229 		.ident = "Dell Latitude E6320",
230 		.matches = {
231 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
232 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
233 		},
234 	},
235 	{	/* Handle problems with rebooting on the Latitude E6420. */
236 		.callback = set_pci_reboot,
237 		.ident = "Dell Latitude E6420",
238 		.matches = {
239 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
240 			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
241 		},
242 	},
243 	{	/* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
244 		.callback = set_bios_reboot,
245 		.ident = "Dell OptiPlex 330",
246 		.matches = {
247 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
248 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
249 			DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
250 		},
251 	},
252 	{	/* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
253 		.callback = set_bios_reboot,
254 		.ident = "Dell OptiPlex 360",
255 		.matches = {
256 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
257 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
258 			DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
259 		},
260 	},
261 	{	/* Handle problems with rebooting on Dell Optiplex 745's SFF */
262 		.callback = set_bios_reboot,
263 		.ident = "Dell OptiPlex 745",
264 		.matches = {
265 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
266 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
267 		},
268 	},
269 	{	/* Handle problems with rebooting on Dell Optiplex 745's DFF */
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, "0MM599"),
276 		},
277 	},
278 	{	/* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
279 		.callback = set_bios_reboot,
280 		.ident = "Dell OptiPlex 745",
281 		.matches = {
282 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
283 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
284 			DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
285 		},
286 	},
287 	{	/* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
288 		.callback = set_bios_reboot,
289 		.ident = "Dell OptiPlex 760",
290 		.matches = {
291 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
292 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
293 			DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
294 		},
295 	},
296 	{	/* Handle problems with rebooting on the OptiPlex 990. */
297 		.callback = set_pci_reboot,
298 		.ident = "Dell OptiPlex 990",
299 		.matches = {
300 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
301 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
302 		},
303 	},
304 	{	/* Handle problems with rebooting on Dell 300's */
305 		.callback = set_bios_reboot,
306 		.ident = "Dell PowerEdge 300",
307 		.matches = {
308 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
309 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
310 		},
311 	},
312 	{	/* Handle problems with rebooting on Dell 1300's */
313 		.callback = set_bios_reboot,
314 		.ident = "Dell PowerEdge 1300",
315 		.matches = {
316 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
317 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
318 		},
319 	},
320 	{	/* Handle problems with rebooting on Dell 2400's */
321 		.callback = set_bios_reboot,
322 		.ident = "Dell PowerEdge 2400",
323 		.matches = {
324 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
325 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
326 		},
327 	},
328 	{	/* Handle problems with rebooting on the Dell PowerEdge C6100. */
329 		.callback = set_pci_reboot,
330 		.ident = "Dell PowerEdge C6100",
331 		.matches = {
332 			DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
333 			DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
334 		},
335 	},
336 	{	/* Handle problems with rebooting on the Precision M6600. */
337 		.callback = set_pci_reboot,
338 		.ident = "Dell Precision M6600",
339 		.matches = {
340 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
341 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
342 		},
343 	},
344 	{	/* Handle problems with rebooting on Dell T5400's */
345 		.callback = set_bios_reboot,
346 		.ident = "Dell Precision T5400",
347 		.matches = {
348 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
349 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
350 		},
351 	},
352 	{	/* Handle problems with rebooting on Dell T7400's */
353 		.callback = set_bios_reboot,
354 		.ident = "Dell Precision T7400",
355 		.matches = {
356 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
357 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
358 		},
359 	},
360 	{	/* Handle problems with rebooting on Dell XPS710 */
361 		.callback = set_bios_reboot,
362 		.ident = "Dell XPS710",
363 		.matches = {
364 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
365 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
366 		},
367 	},
368 
369 	/* Hewlett-Packard */
370 	{	/* Handle problems with rebooting on HP laptops */
371 		.callback = set_bios_reboot,
372 		.ident = "HP Compaq Laptop",
373 		.matches = {
374 			DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
375 			DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
376 		},
377 	},
378 
379 	/* Sony */
380 	{	/* Handle problems with rebooting on Sony VGN-Z540N */
381 		.callback = set_bios_reboot,
382 		.ident = "Sony VGN-Z540N",
383 		.matches = {
384 			DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
385 			DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
386 		},
387 	},
388 
389 	{ }
390 };
391 
392 static int __init reboot_init(void)
393 {
394 	/*
395 	 * Only do the DMI check if reboot_type hasn't been overridden
396 	 * on the command line
397 	 */
398 	if (reboot_default)
399 		dmi_check_system(reboot_dmi_table);
400 	return 0;
401 }
402 core_initcall(reboot_init);
403 
404 static inline void kb_wait(void)
405 {
406 	int i;
407 
408 	for (i = 0; i < 0x10000; i++) {
409 		if ((inb(0x64) & 0x02) == 0)
410 			break;
411 		udelay(2);
412 	}
413 }
414 
415 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
416 {
417 	cpu_emergency_vmxoff();
418 }
419 
420 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
421 static void emergency_vmx_disable_all(void)
422 {
423 	/* Just make sure we won't change CPUs while doing this */
424 	local_irq_disable();
425 
426 	/*
427 	 * We need to disable VMX on all CPUs before rebooting, otherwise
428 	 * we risk hanging up the machine, because the CPU ignore INIT
429 	 * signals when VMX is enabled.
430 	 *
431 	 * We can't take any locks and we may be on an inconsistent
432 	 * state, so we use NMIs as IPIs to tell the other CPUs to disable
433 	 * VMX and halt.
434 	 *
435 	 * For safety, we will avoid running the nmi_shootdown_cpus()
436 	 * stuff unnecessarily, but we don't have a way to check
437 	 * if other CPUs have VMX enabled. So we will call it only if the
438 	 * CPU we are running on has VMX enabled.
439 	 *
440 	 * We will miss cases where VMX is not enabled on all CPUs. This
441 	 * shouldn't do much harm because KVM always enable VMX on all
442 	 * CPUs anyway. But we can miss it on the small window where KVM
443 	 * is still enabling VMX.
444 	 */
445 	if (cpu_has_vmx() && cpu_vmx_enabled()) {
446 		/* Disable VMX on this CPU. */
447 		cpu_vmxoff();
448 
449 		/* Halt and disable VMX on the other CPUs */
450 		nmi_shootdown_cpus(vmxoff_nmi);
451 
452 	}
453 }
454 
455 
456 void __attribute__((weak)) mach_reboot_fixups(void)
457 {
458 }
459 
460 /*
461  * Windows compatible x86 hardware expects the following on reboot:
462  *
463  * 1) If the FADT has the ACPI reboot register flag set, try it
464  * 2) If still alive, write to the keyboard controller
465  * 3) If still alive, write to the ACPI reboot register again
466  * 4) If still alive, write to the keyboard controller again
467  * 5) If still alive, call the EFI runtime service to reboot
468  * 6) If still alive, write to the PCI IO port 0xCF9 to reboot
469  * 7) If still alive, inform BIOS to do a proper reboot
470  *
471  * If the machine is still alive at this stage, it gives up. We default to
472  * following the same pattern, except that if we're still alive after (7) we'll
473  * try to force a triple fault and then cycle between hitting the keyboard
474  * controller and doing that
475  */
476 static void native_machine_emergency_restart(void)
477 {
478 	int i;
479 	int attempt = 0;
480 	int orig_reboot_type = reboot_type;
481 	unsigned short mode;
482 
483 	if (reboot_emergency)
484 		emergency_vmx_disable_all();
485 
486 	tboot_shutdown(TB_SHUTDOWN_REBOOT);
487 
488 	/* Tell the BIOS if we want cold or warm reboot */
489 	mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
490 	*((unsigned short *)__va(0x472)) = mode;
491 
492 	for (;;) {
493 		/* Could also try the reset bit in the Hammer NB */
494 		switch (reboot_type) {
495 		case BOOT_KBD:
496 			mach_reboot_fixups(); /* For board specific fixups */
497 
498 			for (i = 0; i < 10; i++) {
499 				kb_wait();
500 				udelay(50);
501 				outb(0xfe, 0x64); /* Pulse reset low */
502 				udelay(50);
503 			}
504 			if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
505 				attempt = 1;
506 				reboot_type = BOOT_ACPI;
507 			} else {
508 				reboot_type = BOOT_EFI;
509 			}
510 			break;
511 
512 		case BOOT_TRIPLE:
513 			load_idt(&no_idt);
514 			__asm__ __volatile__("int3");
515 
516 			/* We're probably dead after this, but... */
517 			reboot_type = BOOT_KBD;
518 			break;
519 
520 		case BOOT_BIOS:
521 			machine_real_restart(MRR_BIOS);
522 
523 			/* We're probably dead after this, but... */
524 			reboot_type = BOOT_TRIPLE;
525 			break;
526 
527 		case BOOT_ACPI:
528 			acpi_reboot();
529 			reboot_type = BOOT_KBD;
530 			break;
531 
532 		case BOOT_EFI:
533 			if (efi_enabled(EFI_RUNTIME_SERVICES))
534 				efi.reset_system(reboot_mode == REBOOT_WARM ?
535 						 EFI_RESET_WARM :
536 						 EFI_RESET_COLD,
537 						 EFI_SUCCESS, 0, NULL);
538 			reboot_type = BOOT_CF9_COND;
539 			break;
540 
541 		case BOOT_CF9:
542 			port_cf9_safe = true;
543 			/* Fall through */
544 
545 		case BOOT_CF9_COND:
546 			if (port_cf9_safe) {
547 				u8 reboot_code = reboot_mode == REBOOT_WARM ?
548 					0x06 : 0x0E;
549 				u8 cf9 = inb(0xcf9) & ~reboot_code;
550 				outb(cf9|2, 0xcf9); /* Request hard reset */
551 				udelay(50);
552 				/* Actually do the reset */
553 				outb(cf9|reboot_code, 0xcf9);
554 				udelay(50);
555 			}
556 			reboot_type = BOOT_BIOS;
557 			break;
558 		}
559 	}
560 }
561 
562 void native_machine_shutdown(void)
563 {
564 	/* Stop the cpus and apics */
565 #ifdef CONFIG_X86_IO_APIC
566 	/*
567 	 * Disabling IO APIC before local APIC is a workaround for
568 	 * erratum AVR31 in "Intel Atom Processor C2000 Product Family
569 	 * Specification Update". In this situation, interrupts that target
570 	 * a Logical Processor whose Local APIC is either in the process of
571 	 * being hardware disabled or software disabled are neither delivered
572 	 * nor discarded. When this erratum occurs, the processor may hang.
573 	 *
574 	 * Even without the erratum, it still makes sense to quiet IO APIC
575 	 * before disabling Local APIC.
576 	 */
577 	disable_IO_APIC();
578 #endif
579 
580 #ifdef CONFIG_SMP
581 	/*
582 	 * Stop all of the others. Also disable the local irq to
583 	 * not receive the per-cpu timer interrupt which may trigger
584 	 * scheduler's load balance.
585 	 */
586 	local_irq_disable();
587 	stop_other_cpus();
588 #endif
589 
590 	lapic_shutdown();
591 
592 #ifdef CONFIG_HPET_TIMER
593 	hpet_disable();
594 #endif
595 
596 #ifdef CONFIG_X86_64
597 	x86_platform.iommu_shutdown();
598 #endif
599 }
600 
601 static void __machine_emergency_restart(int emergency)
602 {
603 	reboot_emergency = emergency;
604 	machine_ops.emergency_restart();
605 }
606 
607 static void native_machine_restart(char *__unused)
608 {
609 	pr_notice("machine restart\n");
610 
611 	if (!reboot_force)
612 		machine_shutdown();
613 	__machine_emergency_restart(0);
614 }
615 
616 static void native_machine_halt(void)
617 {
618 	/* Stop other cpus and apics */
619 	machine_shutdown();
620 
621 	tboot_shutdown(TB_SHUTDOWN_HALT);
622 
623 	stop_this_cpu(NULL);
624 }
625 
626 static void native_machine_power_off(void)
627 {
628 	if (pm_power_off) {
629 		if (!reboot_force)
630 			machine_shutdown();
631 		pm_power_off();
632 	}
633 	/* A fallback in case there is no PM info available */
634 	tboot_shutdown(TB_SHUTDOWN_HALT);
635 }
636 
637 struct machine_ops machine_ops = {
638 	.power_off = native_machine_power_off,
639 	.shutdown = native_machine_shutdown,
640 	.emergency_restart = native_machine_emergency_restart,
641 	.restart = native_machine_restart,
642 	.halt = native_machine_halt,
643 #ifdef CONFIG_KEXEC
644 	.crash_shutdown = native_machine_crash_shutdown,
645 #endif
646 };
647 
648 void machine_power_off(void)
649 {
650 	machine_ops.power_off();
651 }
652 
653 void machine_shutdown(void)
654 {
655 	machine_ops.shutdown();
656 }
657 
658 void machine_emergency_restart(void)
659 {
660 	__machine_emergency_restart(1);
661 }
662 
663 void machine_restart(char *cmd)
664 {
665 	machine_ops.restart(cmd);
666 }
667 
668 void machine_halt(void)
669 {
670 	machine_ops.halt();
671 }
672 
673 #ifdef CONFIG_KEXEC
674 void machine_crash_shutdown(struct pt_regs *regs)
675 {
676 	machine_ops.crash_shutdown(regs);
677 }
678 #endif
679 
680 
681 #if defined(CONFIG_SMP)
682 
683 /* This keeps a track of which one is crashing cpu. */
684 static int crashing_cpu;
685 static nmi_shootdown_cb shootdown_callback;
686 
687 static atomic_t waiting_for_crash_ipi;
688 
689 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
690 {
691 	int cpu;
692 
693 	cpu = raw_smp_processor_id();
694 
695 	/*
696 	 * Don't do anything if this handler is invoked on crashing cpu.
697 	 * Otherwise, system will completely hang. Crashing cpu can get
698 	 * an NMI if system was initially booted with nmi_watchdog parameter.
699 	 */
700 	if (cpu == crashing_cpu)
701 		return NMI_HANDLED;
702 	local_irq_disable();
703 
704 	shootdown_callback(cpu, regs);
705 
706 	atomic_dec(&waiting_for_crash_ipi);
707 	/* Assume hlt works */
708 	halt();
709 	for (;;)
710 		cpu_relax();
711 
712 	return NMI_HANDLED;
713 }
714 
715 static void smp_send_nmi_allbutself(void)
716 {
717 	apic->send_IPI_allbutself(NMI_VECTOR);
718 }
719 
720 /*
721  * Halt all other CPUs, calling the specified function on each of them
722  *
723  * This function can be used to halt all other CPUs on crash
724  * or emergency reboot time. The function passed as parameter
725  * will be called inside a NMI handler on all CPUs.
726  */
727 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
728 {
729 	unsigned long msecs;
730 	local_irq_disable();
731 
732 	/* Make a note of crashing cpu. Will be used in NMI callback. */
733 	crashing_cpu = safe_smp_processor_id();
734 
735 	shootdown_callback = callback;
736 
737 	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
738 	/* Would it be better to replace the trap vector here? */
739 	if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
740 				 NMI_FLAG_FIRST, "crash"))
741 		return;		/* Return what? */
742 	/*
743 	 * Ensure the new callback function is set before sending
744 	 * out the NMI
745 	 */
746 	wmb();
747 
748 	smp_send_nmi_allbutself();
749 
750 	msecs = 1000; /* Wait at most a second for the other cpus to stop */
751 	while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
752 		mdelay(1);
753 		msecs--;
754 	}
755 
756 	/* Leave the nmi callback set */
757 }
758 #else /* !CONFIG_SMP */
759 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
760 {
761 	/* No other CPUs to shoot down */
762 }
763 #endif
764