xref: /linux/arch/x86/kernel/reboot.c (revision cb299ba8b5ef2239429484072fea394cd7581bd7)
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 <acpi/reboot.h>
10 #include <asm/io.h>
11 #include <asm/apic.h>
12 #include <asm/desc.h>
13 #include <asm/hpet.h>
14 #include <asm/pgtable.h>
15 #include <asm/proto.h>
16 #include <asm/reboot_fixups.h>
17 #include <asm/reboot.h>
18 #include <asm/pci_x86.h>
19 #include <asm/virtext.h>
20 #include <asm/cpu.h>
21 
22 #ifdef CONFIG_X86_32
23 # include <linux/ctype.h>
24 # include <linux/mc146818rtc.h>
25 #else
26 # include <asm/x86_init.h>
27 #endif
28 
29 /*
30  * Power off function, if any
31  */
32 void (*pm_power_off)(void);
33 EXPORT_SYMBOL(pm_power_off);
34 
35 static const struct desc_ptr no_idt = {};
36 static int reboot_mode;
37 enum reboot_type reboot_type = BOOT_KBD;
38 int reboot_force;
39 
40 #if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
41 static int reboot_cpu = -1;
42 #endif
43 
44 /* This is set if we need to go through the 'emergency' path.
45  * When machine_emergency_restart() is called, we may be on
46  * an inconsistent state and won't be able to do a clean cleanup
47  */
48 static int reboot_emergency;
49 
50 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
51 bool port_cf9_safe = false;
52 
53 /* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci]
54    warm   Don't set the cold reboot flag
55    cold   Set the cold reboot flag
56    bios   Reboot by jumping through the BIOS (only for X86_32)
57    smp    Reboot by executing reset on BSP or other CPU (only for X86_32)
58    triple Force a triple fault (init)
59    kbd    Use the keyboard controller. cold reset (default)
60    acpi   Use the RESET_REG in the FADT
61    efi    Use efi reset_system runtime service
62    pci    Use the so-called "PCI reset register", CF9
63    force  Avoid anything that could hang.
64  */
65 static int __init reboot_setup(char *str)
66 {
67 	for (;;) {
68 		switch (*str) {
69 		case 'w':
70 			reboot_mode = 0x1234;
71 			break;
72 
73 		case 'c':
74 			reboot_mode = 0;
75 			break;
76 
77 #ifdef CONFIG_X86_32
78 #ifdef CONFIG_SMP
79 		case 's':
80 			if (isdigit(*(str+1))) {
81 				reboot_cpu = (int) (*(str+1) - '0');
82 				if (isdigit(*(str+2)))
83 					reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
84 			}
85 				/* we will leave sorting out the final value
86 				   when we are ready to reboot, since we might not
87 				   have detected BSP APIC ID or smp_num_cpu */
88 			break;
89 #endif /* CONFIG_SMP */
90 
91 		case 'b':
92 #endif
93 		case 'a':
94 		case 'k':
95 		case 't':
96 		case 'e':
97 		case 'p':
98 			reboot_type = *str;
99 			break;
100 
101 		case 'f':
102 			reboot_force = 1;
103 			break;
104 		}
105 
106 		str = strchr(str, ',');
107 		if (str)
108 			str++;
109 		else
110 			break;
111 	}
112 	return 1;
113 }
114 
115 __setup("reboot=", reboot_setup);
116 
117 
118 #ifdef CONFIG_X86_32
119 /*
120  * Reboot options and system auto-detection code provided by
121  * Dell Inc. so their systems "just work". :-)
122  */
123 
124 /*
125  * Some machines require the "reboot=b"  commandline option,
126  * this quirk makes that automatic.
127  */
128 static int __init set_bios_reboot(const struct dmi_system_id *d)
129 {
130 	if (reboot_type != BOOT_BIOS) {
131 		reboot_type = BOOT_BIOS;
132 		printk(KERN_INFO "%s series board detected. Selecting BIOS-method for reboots.\n", d->ident);
133 	}
134 	return 0;
135 }
136 
137 static struct dmi_system_id __initdata reboot_dmi_table[] = {
138 	{	/* Handle problems with rebooting on Dell E520's */
139 		.callback = set_bios_reboot,
140 		.ident = "Dell E520",
141 		.matches = {
142 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
143 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
144 		},
145 	},
146 	{	/* Handle problems with rebooting on Dell 1300's */
147 		.callback = set_bios_reboot,
148 		.ident = "Dell PowerEdge 1300",
149 		.matches = {
150 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
151 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
152 		},
153 	},
154 	{	/* Handle problems with rebooting on Dell 300's */
155 		.callback = set_bios_reboot,
156 		.ident = "Dell PowerEdge 300",
157 		.matches = {
158 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
159 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
160 		},
161 	},
162 	{       /* Handle problems with rebooting on Dell Optiplex 745's SFF*/
163 		.callback = set_bios_reboot,
164 		.ident = "Dell OptiPlex 745",
165 		.matches = {
166 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
167 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
168 		},
169 	},
170 	{       /* Handle problems with rebooting on Dell Optiplex 745's DFF*/
171 		.callback = set_bios_reboot,
172 		.ident = "Dell OptiPlex 745",
173 		.matches = {
174 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
175 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
176 			DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
177 		},
178 	},
179 	{       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
180 		.callback = set_bios_reboot,
181 		.ident = "Dell OptiPlex 745",
182 		.matches = {
183 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
184 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
185 			DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
186 		},
187 	},
188 	{   /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
189 		.callback = set_bios_reboot,
190 		.ident = "Dell OptiPlex 330",
191 		.matches = {
192 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
193 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
194 			DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
195 		},
196 	},
197 	{   /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
198 		.callback = set_bios_reboot,
199 		.ident = "Dell OptiPlex 360",
200 		.matches = {
201 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
202 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
203 			DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
204 		},
205 	},
206 	{	/* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G*/
207 		.callback = set_bios_reboot,
208 		.ident = "Dell OptiPlex 760",
209 		.matches = {
210 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
211 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
212 			DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
213 		},
214 	},
215 	{	/* Handle problems with rebooting on Dell 2400's */
216 		.callback = set_bios_reboot,
217 		.ident = "Dell PowerEdge 2400",
218 		.matches = {
219 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
220 			DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
221 		},
222 	},
223 	{	/* Handle problems with rebooting on Dell T5400's */
224 		.callback = set_bios_reboot,
225 		.ident = "Dell Precision T5400",
226 		.matches = {
227 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
228 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
229 		},
230 	},
231 	{	/* Handle problems with rebooting on Dell T7400's */
232 		.callback = set_bios_reboot,
233 		.ident = "Dell Precision T7400",
234 		.matches = {
235 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
236 			DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
237 		},
238 	},
239 	{	/* Handle problems with rebooting on HP laptops */
240 		.callback = set_bios_reboot,
241 		.ident = "HP Compaq Laptop",
242 		.matches = {
243 			DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
244 			DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
245 		},
246 	},
247 	{	/* Handle problems with rebooting on Dell XPS710 */
248 		.callback = set_bios_reboot,
249 		.ident = "Dell XPS710",
250 		.matches = {
251 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
252 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
253 		},
254 	},
255 	{	/* Handle problems with rebooting on Dell DXP061 */
256 		.callback = set_bios_reboot,
257 		.ident = "Dell DXP061",
258 		.matches = {
259 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
260 			DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
261 		},
262 	},
263 	{	/* Handle problems with rebooting on Sony VGN-Z540N */
264 		.callback = set_bios_reboot,
265 		.ident = "Sony VGN-Z540N",
266 		.matches = {
267 			DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
268 			DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
269 		},
270 	},
271 	{	/* Handle problems with rebooting on CompuLab SBC-FITPC2 */
272 		.callback = set_bios_reboot,
273 		.ident = "CompuLab SBC-FITPC2",
274 		.matches = {
275 			DMI_MATCH(DMI_SYS_VENDOR, "CompuLab"),
276 			DMI_MATCH(DMI_PRODUCT_NAME, "SBC-FITPC2"),
277 		},
278 	},
279 	{       /* Handle problems with rebooting on ASUS P4S800 */
280 		.callback = set_bios_reboot,
281 		.ident = "ASUS P4S800",
282 		.matches = {
283 			DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
284 			DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
285 		},
286 	},
287 	{ }
288 };
289 
290 static int __init reboot_init(void)
291 {
292 	dmi_check_system(reboot_dmi_table);
293 	return 0;
294 }
295 core_initcall(reboot_init);
296 
297 /* The following code and data reboots the machine by switching to real
298    mode and jumping to the BIOS reset entry point, as if the CPU has
299    really been reset.  The previous version asked the keyboard
300    controller to pulse the CPU reset line, which is more thorough, but
301    doesn't work with at least one type of 486 motherboard.  It is easy
302    to stop this code working; hence the copious comments. */
303 static const unsigned long long
304 real_mode_gdt_entries [3] =
305 {
306 	0x0000000000000000ULL,	/* Null descriptor */
307 	0x00009b000000ffffULL,	/* 16-bit real-mode 64k code at 0x00000000 */
308 	0x000093000100ffffULL	/* 16-bit real-mode 64k data at 0x00000100 */
309 };
310 
311 static const struct desc_ptr
312 real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, (long)real_mode_gdt_entries },
313 real_mode_idt = { 0x3ff, 0 };
314 
315 /* This is 16-bit protected mode code to disable paging and the cache,
316    switch to real mode and jump to the BIOS reset code.
317 
318    The instruction that switches to real mode by writing to CR0 must be
319    followed immediately by a far jump instruction, which set CS to a
320    valid value for real mode, and flushes the prefetch queue to avoid
321    running instructions that have already been decoded in protected
322    mode.
323 
324    Clears all the flags except ET, especially PG (paging), PE
325    (protected-mode enable) and TS (task switch for coprocessor state
326    save).  Flushes the TLB after paging has been disabled.  Sets CD and
327    NW, to disable the cache on a 486, and invalidates the cache.  This
328    is more like the state of a 486 after reset.  I don't know if
329    something else should be done for other chips.
330 
331    More could be done here to set up the registers as if a CPU reset had
332    occurred; hopefully real BIOSs don't assume much. */
333 static const unsigned char real_mode_switch [] =
334 {
335 	0x66, 0x0f, 0x20, 0xc0,			/*    movl  %cr0,%eax        */
336 	0x66, 0x83, 0xe0, 0x11,			/*    andl  $0x00000011,%eax */
337 	0x66, 0x0d, 0x00, 0x00, 0x00, 0x60,	/*    orl   $0x60000000,%eax */
338 	0x66, 0x0f, 0x22, 0xc0,			/*    movl  %eax,%cr0        */
339 	0x66, 0x0f, 0x22, 0xd8,			/*    movl  %eax,%cr3        */
340 	0x66, 0x0f, 0x20, 0xc3,			/*    movl  %cr0,%ebx        */
341 	0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60,	/*    andl  $0x60000000,%ebx */
342 	0x74, 0x02,				/*    jz    f                */
343 	0x0f, 0x09,				/*    wbinvd                 */
344 	0x24, 0x10,				/* f: andb  $0x10,al         */
345 	0x66, 0x0f, 0x22, 0xc0			/*    movl  %eax,%cr0        */
346 };
347 static const unsigned char jump_to_bios [] =
348 {
349 	0xea, 0x00, 0x00, 0xff, 0xff		/*    ljmp  $0xffff,$0x0000  */
350 };
351 
352 /*
353  * Switch to real mode and then execute the code
354  * specified by the code and length parameters.
355  * We assume that length will aways be less that 100!
356  */
357 void machine_real_restart(const unsigned char *code, int length)
358 {
359 	local_irq_disable();
360 
361 	/* Write zero to CMOS register number 0x0f, which the BIOS POST
362 	   routine will recognize as telling it to do a proper reboot.  (Well
363 	   that's what this book in front of me says -- it may only apply to
364 	   the Phoenix BIOS though, it's not clear).  At the same time,
365 	   disable NMIs by setting the top bit in the CMOS address register,
366 	   as we're about to do peculiar things to the CPU.  I'm not sure if
367 	   `outb_p' is needed instead of just `outb'.  Use it to be on the
368 	   safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
369 	 */
370 	spin_lock(&rtc_lock);
371 	CMOS_WRITE(0x00, 0x8f);
372 	spin_unlock(&rtc_lock);
373 
374 	/*
375 	 * Switch back to the initial page table.
376 	 */
377 	load_cr3(initial_page_table);
378 
379 	/* Write 0x1234 to absolute memory location 0x472.  The BIOS reads
380 	   this on booting to tell it to "Bypass memory test (also warm
381 	   boot)".  This seems like a fairly standard thing that gets set by
382 	   REBOOT.COM programs, and the previous reset routine did this
383 	   too. */
384 	*((unsigned short *)0x472) = reboot_mode;
385 
386 	/* For the switch to real mode, copy some code to low memory.  It has
387 	   to be in the first 64k because it is running in 16-bit mode, and it
388 	   has to have the same physical and virtual address, because it turns
389 	   off paging.  Copy it near the end of the first page, out of the way
390 	   of BIOS variables. */
391 	memcpy((void *)(0x1000 - sizeof(real_mode_switch) - 100),
392 		real_mode_switch, sizeof (real_mode_switch));
393 	memcpy((void *)(0x1000 - 100), code, length);
394 
395 	/* Set up the IDT for real mode. */
396 	load_idt(&real_mode_idt);
397 
398 	/* Set up a GDT from which we can load segment descriptors for real
399 	   mode.  The GDT is not used in real mode; it is just needed here to
400 	   prepare the descriptors. */
401 	load_gdt(&real_mode_gdt);
402 
403 	/* Load the data segment registers, and thus the descriptors ready for
404 	   real mode.  The base address of each segment is 0x100, 16 times the
405 	   selector value being loaded here.  This is so that the segment
406 	   registers don't have to be reloaded after switching to real mode:
407 	   the values are consistent for real mode operation already. */
408 	__asm__ __volatile__ ("movl $0x0010,%%eax\n"
409 				"\tmovl %%eax,%%ds\n"
410 				"\tmovl %%eax,%%es\n"
411 				"\tmovl %%eax,%%fs\n"
412 				"\tmovl %%eax,%%gs\n"
413 				"\tmovl %%eax,%%ss" : : : "eax");
414 
415 	/* Jump to the 16-bit code that we copied earlier.  It disables paging
416 	   and the cache, switches to real mode, and jumps to the BIOS reset
417 	   entry point. */
418 	__asm__ __volatile__ ("ljmp $0x0008,%0"
419 				:
420 				: "i" ((void *)(0x1000 - sizeof (real_mode_switch) - 100)));
421 }
422 #ifdef CONFIG_APM_MODULE
423 EXPORT_SYMBOL(machine_real_restart);
424 #endif
425 
426 #endif /* CONFIG_X86_32 */
427 
428 /*
429  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
430  */
431 static int __init set_pci_reboot(const struct dmi_system_id *d)
432 {
433 	if (reboot_type != BOOT_CF9) {
434 		reboot_type = BOOT_CF9;
435 		printk(KERN_INFO "%s series board detected. "
436 		       "Selecting PCI-method for reboots.\n", d->ident);
437 	}
438 	return 0;
439 }
440 
441 static struct dmi_system_id __initdata pci_reboot_dmi_table[] = {
442 	{	/* Handle problems with rebooting on Apple MacBook5 */
443 		.callback = set_pci_reboot,
444 		.ident = "Apple MacBook5",
445 		.matches = {
446 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
447 			DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
448 		},
449 	},
450 	{	/* Handle problems with rebooting on Apple MacBookPro5 */
451 		.callback = set_pci_reboot,
452 		.ident = "Apple MacBookPro5",
453 		.matches = {
454 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
455 			DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
456 		},
457 	},
458 	{	/* Handle problems with rebooting on Apple Macmini3,1 */
459 		.callback = set_pci_reboot,
460 		.ident = "Apple Macmini3,1",
461 		.matches = {
462 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
463 			DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
464 		},
465 	},
466 	{	/* Handle problems with rebooting on the iMac9,1. */
467 		.callback = set_pci_reboot,
468 		.ident = "Apple iMac9,1",
469 		.matches = {
470 			DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
471 			DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
472 		},
473 	},
474 	{ }
475 };
476 
477 static int __init pci_reboot_init(void)
478 {
479 	dmi_check_system(pci_reboot_dmi_table);
480 	return 0;
481 }
482 core_initcall(pci_reboot_init);
483 
484 static inline void kb_wait(void)
485 {
486 	int i;
487 
488 	for (i = 0; i < 0x10000; i++) {
489 		if ((inb(0x64) & 0x02) == 0)
490 			break;
491 		udelay(2);
492 	}
493 }
494 
495 static void vmxoff_nmi(int cpu, struct die_args *args)
496 {
497 	cpu_emergency_vmxoff();
498 }
499 
500 /* Use NMIs as IPIs to tell all CPUs to disable virtualization
501  */
502 static void emergency_vmx_disable_all(void)
503 {
504 	/* Just make sure we won't change CPUs while doing this */
505 	local_irq_disable();
506 
507 	/* We need to disable VMX on all CPUs before rebooting, otherwise
508 	 * we risk hanging up the machine, because the CPU ignore INIT
509 	 * signals when VMX is enabled.
510 	 *
511 	 * We can't take any locks and we may be on an inconsistent
512 	 * state, so we use NMIs as IPIs to tell the other CPUs to disable
513 	 * VMX and halt.
514 	 *
515 	 * For safety, we will avoid running the nmi_shootdown_cpus()
516 	 * stuff unnecessarily, but we don't have a way to check
517 	 * if other CPUs have VMX enabled. So we will call it only if the
518 	 * CPU we are running on has VMX enabled.
519 	 *
520 	 * We will miss cases where VMX is not enabled on all CPUs. This
521 	 * shouldn't do much harm because KVM always enable VMX on all
522 	 * CPUs anyway. But we can miss it on the small window where KVM
523 	 * is still enabling VMX.
524 	 */
525 	if (cpu_has_vmx() && cpu_vmx_enabled()) {
526 		/* Disable VMX on this CPU.
527 		 */
528 		cpu_vmxoff();
529 
530 		/* Halt and disable VMX on the other CPUs */
531 		nmi_shootdown_cpus(vmxoff_nmi);
532 
533 	}
534 }
535 
536 
537 void __attribute__((weak)) mach_reboot_fixups(void)
538 {
539 }
540 
541 static void native_machine_emergency_restart(void)
542 {
543 	int i;
544 
545 	if (reboot_emergency)
546 		emergency_vmx_disable_all();
547 
548 	tboot_shutdown(TB_SHUTDOWN_REBOOT);
549 
550 	/* Tell the BIOS if we want cold or warm reboot */
551 	*((unsigned short *)__va(0x472)) = reboot_mode;
552 
553 	for (;;) {
554 		/* Could also try the reset bit in the Hammer NB */
555 		switch (reboot_type) {
556 		case BOOT_KBD:
557 			mach_reboot_fixups(); /* for board specific fixups */
558 
559 			for (i = 0; i < 10; i++) {
560 				kb_wait();
561 				udelay(50);
562 				outb(0xfe, 0x64); /* pulse reset low */
563 				udelay(50);
564 			}
565 
566 		case BOOT_TRIPLE:
567 			load_idt(&no_idt);
568 			__asm__ __volatile__("int3");
569 
570 			reboot_type = BOOT_KBD;
571 			break;
572 
573 #ifdef CONFIG_X86_32
574 		case BOOT_BIOS:
575 			machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
576 
577 			reboot_type = BOOT_KBD;
578 			break;
579 #endif
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 #ifdef CONFIG_X86_32
622 	/* See if there has been given a command line override */
623 	if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
624 		cpu_online(reboot_cpu))
625 		reboot_cpu_id = reboot_cpu;
626 #endif
627 
628 	/* Make certain the cpu I'm about to reboot on is online */
629 	if (!cpu_online(reboot_cpu_id))
630 		reboot_cpu_id = smp_processor_id();
631 
632 	/* Make certain I only run on the appropriate processor */
633 	set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
634 
635 	/* O.K Now that I'm on the appropriate processor,
636 	 * stop all of the others.
637 	 */
638 	smp_send_stop();
639 #endif
640 
641 	lapic_shutdown();
642 
643 #ifdef CONFIG_X86_IO_APIC
644 	disable_IO_APIC();
645 #endif
646 
647 #ifdef CONFIG_HPET_TIMER
648 	hpet_disable();
649 #endif
650 
651 #ifdef CONFIG_X86_64
652 	x86_platform.iommu_shutdown();
653 #endif
654 }
655 
656 static void __machine_emergency_restart(int emergency)
657 {
658 	reboot_emergency = emergency;
659 	machine_ops.emergency_restart();
660 }
661 
662 static void native_machine_restart(char *__unused)
663 {
664 	printk("machine restart\n");
665 
666 	if (!reboot_force)
667 		machine_shutdown();
668 	__machine_emergency_restart(0);
669 }
670 
671 static void native_machine_halt(void)
672 {
673 	/* stop other cpus and apics */
674 	machine_shutdown();
675 
676 	tboot_shutdown(TB_SHUTDOWN_HALT);
677 
678 	/* stop this cpu */
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(struct notifier_block *self,
746 			unsigned long val, void *data)
747 {
748 	int cpu;
749 
750 	if (val != DIE_NMI_IPI)
751 		return NOTIFY_OK;
752 
753 	cpu = raw_smp_processor_id();
754 
755 	/* Don't do anything if this handler is invoked on crashing cpu.
756 	 * Otherwise, system will completely hang. Crashing cpu can get
757 	 * an NMI if system was initially booted with nmi_watchdog parameter.
758 	 */
759 	if (cpu == crashing_cpu)
760 		return NOTIFY_STOP;
761 	local_irq_disable();
762 
763 	shootdown_callback(cpu, (struct die_args *)data);
764 
765 	atomic_dec(&waiting_for_crash_ipi);
766 	/* Assume hlt works */
767 	halt();
768 	for (;;)
769 		cpu_relax();
770 
771 	return 1;
772 }
773 
774 static void smp_send_nmi_allbutself(void)
775 {
776 	apic->send_IPI_allbutself(NMI_VECTOR);
777 }
778 
779 static struct notifier_block crash_nmi_nb = {
780 	.notifier_call = crash_nmi_callback,
781 };
782 
783 /* Halt all other CPUs, calling the specified function on each of them
784  *
785  * This function can be used to halt all other CPUs on crash
786  * or emergency reboot time. The function passed as parameter
787  * will be called inside a NMI handler on all CPUs.
788  */
789 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
790 {
791 	unsigned long msecs;
792 	local_irq_disable();
793 
794 	/* Make a note of crashing cpu. Will be used in NMI callback.*/
795 	crashing_cpu = safe_smp_processor_id();
796 
797 	shootdown_callback = callback;
798 
799 	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
800 	/* Would it be better to replace the trap vector here? */
801 	if (register_die_notifier(&crash_nmi_nb))
802 		return;		/* return what? */
803 	/* Ensure the new callback function is set before sending
804 	 * out the NMI
805 	 */
806 	wmb();
807 
808 	smp_send_nmi_allbutself();
809 
810 	msecs = 1000; /* Wait at most a second for the other cpus to stop */
811 	while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
812 		mdelay(1);
813 		msecs--;
814 	}
815 
816 	/* Leave the nmi callback set */
817 }
818 #else /* !CONFIG_SMP */
819 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
820 {
821 	/* No other CPUs to shoot down */
822 }
823 #endif
824