Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/arch/x86/kernel/reboot.c

  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 #include <asm/efi.h>
 32 
 33 /*
 34  * Power off function, if any
 35  */
 36 void (*pm_power_off)(void);
 37 EXPORT_SYMBOL(pm_power_off);
 38 
 39 static const struct desc_ptr no_idt = {};
 40 
 41 /*
 42  * This is set if we need to go through the 'emergency' path.
 43  * When machine_emergency_restart() is called, we may be on
 44  * an inconsistent state and won't be able to do a clean cleanup
 45  */
 46 static int reboot_emergency;
 47 
 48 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
 49 bool port_cf9_safe = false;
 50 
 51 /*
 52  * Reboot options and system auto-detection code provided by
 53  * Dell Inc. so their systems "just work". :-)
 54  */
 55 
 56 /*
 57  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
 58  * this quirk makes that automatic.
 59  */
 60 static int __init set_bios_reboot(const struct dmi_system_id *d)
 61 {
 62         if (reboot_type != BOOT_BIOS) {
 63                 reboot_type = BOOT_BIOS;
 64                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 65                         d->ident, "BIOS");
 66         }
 67         return 0;
 68 }
 69 
 70 void __noreturn machine_real_restart(unsigned int type)
 71 {
 72         local_irq_disable();
 73 
 74         /*
 75          * Write zero to CMOS register number 0x0f, which the BIOS POST
 76          * routine will recognize as telling it to do a proper reboot.  (Well
 77          * that's what this book in front of me says -- it may only apply to
 78          * the Phoenix BIOS though, it's not clear).  At the same time,
 79          * disable NMIs by setting the top bit in the CMOS address register,
 80          * as we're about to do peculiar things to the CPU.  I'm not sure if
 81          * `outb_p' is needed instead of just `outb'.  Use it to be on the
 82          * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 83          */
 84         spin_lock(&rtc_lock);
 85         CMOS_WRITE(0x00, 0x8f);
 86         spin_unlock(&rtc_lock);
 87 
 88         /*
 89          * Switch back to the initial page table.
 90          */
 91 #ifdef CONFIG_X86_32
 92         load_cr3(initial_page_table);
 93 #else
 94         write_cr3(real_mode_header->trampoline_pgd);
 95 #endif
 96 
 97         /* Jump to the identity-mapped low memory code */
 98 #ifdef CONFIG_X86_32
 99         asm volatile("jmpl *%0" : :
100                      "rm" (real_mode_header->machine_real_restart_asm),
101                      "a" (type));
102 #else
103         asm volatile("ljmpl *%0" : :
104                      "m" (real_mode_header->machine_real_restart_asm),
105                      "D" (type));
106 #endif
107         unreachable();
108 }
109 #ifdef CONFIG_APM_MODULE
110 EXPORT_SYMBOL(machine_real_restart);
111 #endif
112 
113 /*
114  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
115  */
116 static int __init set_pci_reboot(const struct dmi_system_id *d)
117 {
118         if (reboot_type != BOOT_CF9_FORCE) {
119                 reboot_type = BOOT_CF9_FORCE;
120                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
121                         d->ident, "PCI");
122         }
123         return 0;
124 }
125 
126 static int __init set_kbd_reboot(const struct dmi_system_id *d)
127 {
128         if (reboot_type != BOOT_KBD) {
129                 reboot_type = BOOT_KBD;
130                 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
131                         d->ident, "KBD");
132         }
133         return 0;
134 }
135 
136 /*
137  * This is a single dmi_table handling all reboot quirks.
138  */
139 static struct dmi_system_id __initdata reboot_dmi_table[] = {
140 
141         /* Acer */
142         {       /* Handle reboot issue on Acer Aspire one */
143                 .callback = set_kbd_reboot,
144                 .ident = "Acer Aspire One A110",
145                 .matches = {
146                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
147                         DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
148                 },
149         },
150 
151         /* Apple */
152         {       /* Handle problems with rebooting on Apple MacBook5 */
153                 .callback = set_pci_reboot,
154                 .ident = "Apple MacBook5",
155                 .matches = {
156                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
157                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
158                 },
159         },
160         {       /* Handle problems with rebooting on Apple MacBookPro5 */
161                 .callback = set_pci_reboot,
162                 .ident = "Apple MacBookPro5",
163                 .matches = {
164                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
165                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
166                 },
167         },
168         {       /* Handle problems with rebooting on Apple Macmini3,1 */
169                 .callback = set_pci_reboot,
170                 .ident = "Apple Macmini3,1",
171                 .matches = {
172                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
173                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
174                 },
175         },
176         {       /* Handle problems with rebooting on the iMac9,1. */
177                 .callback = set_pci_reboot,
178                 .ident = "Apple iMac9,1",
179                 .matches = {
180                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
181                         DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
182                 },
183         },
184 
185         /* ASUS */
186         {       /* Handle problems with rebooting on ASUS P4S800 */
187                 .callback = set_bios_reboot,
188                 .ident = "ASUS P4S800",
189                 .matches = {
190                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
191                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
192                 },
193         },
194 
195         /* Certec */
196         {       /* Handle problems with rebooting on Certec BPC600 */
197                 .callback = set_pci_reboot,
198                 .ident = "Certec BPC600",
199                 .matches = {
200                         DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
201                         DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
202                 },
203         },
204 
205         /* Dell */
206         {       /* Handle problems with rebooting on Dell DXP061 */
207                 .callback = set_bios_reboot,
208                 .ident = "Dell DXP061",
209                 .matches = {
210                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
211                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
212                 },
213         },
214         {       /* Handle problems with rebooting on Dell E520's */
215                 .callback = set_bios_reboot,
216                 .ident = "Dell E520",
217                 .matches = {
218                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
219                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
220                 },
221         },
222         {       /* Handle problems with rebooting on the Latitude E5410. */
223                 .callback = set_pci_reboot,
224                 .ident = "Dell Latitude E5410",
225                 .matches = {
226                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
227                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
228                 },
229         },
230         {       /* Handle problems with rebooting on the Latitude E5420. */
231                 .callback = set_pci_reboot,
232                 .ident = "Dell Latitude E5420",
233                 .matches = {
234                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
235                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
236                 },
237         },
238         {       /* Handle problems with rebooting on the Latitude E6320. */
239                 .callback = set_pci_reboot,
240                 .ident = "Dell Latitude E6320",
241                 .matches = {
242                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
243                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
244                 },
245         },
246         {       /* Handle problems with rebooting on the Latitude E6420. */
247                 .callback = set_pci_reboot,
248                 .ident = "Dell Latitude E6420",
249                 .matches = {
250                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
251                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
252                 },
253         },
254         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
255                 .callback = set_bios_reboot,
256                 .ident = "Dell OptiPlex 330",
257                 .matches = {
258                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
259                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
260                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
261                 },
262         },
263         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
264                 .callback = set_bios_reboot,
265                 .ident = "Dell OptiPlex 360",
266                 .matches = {
267                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
268                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
269                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
270                 },
271         },
272         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
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                 },
279         },
280         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
281                 .callback = set_bios_reboot,
282                 .ident = "Dell OptiPlex 745",
283                 .matches = {
284                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
285                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
286                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
287                 },
288         },
289         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
290                 .callback = set_bios_reboot,
291                 .ident = "Dell OptiPlex 745",
292                 .matches = {
293                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
294                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
295                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
296                 },
297         },
298         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
299                 .callback = set_bios_reboot,
300                 .ident = "Dell OptiPlex 760",
301                 .matches = {
302                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
303                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
304                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
305                 },
306         },
307         {       /* Handle problems with rebooting on the OptiPlex 990. */
308                 .callback = set_pci_reboot,
309                 .ident = "Dell OptiPlex 990",
310                 .matches = {
311                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
312                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
313                 },
314         },
315         {       /* Handle problems with rebooting on Dell 300's */
316                 .callback = set_bios_reboot,
317                 .ident = "Dell PowerEdge 300",
318                 .matches = {
319                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
320                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
321                 },
322         },
323         {       /* Handle problems with rebooting on Dell 1300's */
324                 .callback = set_bios_reboot,
325                 .ident = "Dell PowerEdge 1300",
326                 .matches = {
327                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
328                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
329                 },
330         },
331         {       /* Handle problems with rebooting on Dell 2400's */
332                 .callback = set_bios_reboot,
333                 .ident = "Dell PowerEdge 2400",
334                 .matches = {
335                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
336                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
337                 },
338         },
339         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
340                 .callback = set_pci_reboot,
341                 .ident = "Dell PowerEdge C6100",
342                 .matches = {
343                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
344                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
345                 },
346         },
347         {       /* Handle problems with rebooting on the Precision M6600. */
348                 .callback = set_pci_reboot,
349                 .ident = "Dell Precision M6600",
350                 .matches = {
351                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
352                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
353                 },
354         },
355         {       /* Handle problems with rebooting on Dell T5400's */
356                 .callback = set_bios_reboot,
357                 .ident = "Dell Precision T5400",
358                 .matches = {
359                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
360                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
361                 },
362         },
363         {       /* Handle problems with rebooting on Dell T7400's */
364                 .callback = set_bios_reboot,
365                 .ident = "Dell Precision T7400",
366                 .matches = {
367                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
368                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
369                 },
370         },
371         {       /* Handle problems with rebooting on Dell XPS710 */
372                 .callback = set_bios_reboot,
373                 .ident = "Dell XPS710",
374                 .matches = {
375                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
376                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
377                 },
378         },
379 
380         /* Hewlett-Packard */
381         {       /* Handle problems with rebooting on HP laptops */
382                 .callback = set_bios_reboot,
383                 .ident = "HP Compaq Laptop",
384                 .matches = {
385                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
386                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
387                 },
388         },
389 
390         /* Sony */
391         {       /* Handle problems with rebooting on Sony VGN-Z540N */
392                 .callback = set_bios_reboot,
393                 .ident = "Sony VGN-Z540N",
394                 .matches = {
395                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
396                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
397                 },
398         },
399 
400         { }
401 };
402 
403 static int __init reboot_init(void)
404 {
405         int rv;
406 
407         /*
408          * Only do the DMI check if reboot_type hasn't been overridden
409          * on the command line
410          */
411         if (!reboot_default)
412                 return 0;
413 
414         /*
415          * The DMI quirks table takes precedence. If no quirks entry
416          * matches and the ACPI Hardware Reduced bit is set, force EFI
417          * reboot.
418          */
419         rv = dmi_check_system(reboot_dmi_table);
420 
421         if (!rv && efi_reboot_required())
422                 reboot_type = BOOT_EFI;
423 
424         return 0;
425 }
426 core_initcall(reboot_init);
427 
428 static inline void kb_wait(void)
429 {
430         int i;
431 
432         for (i = 0; i < 0x10000; i++) {
433                 if ((inb(0x64) & 0x02) == 0)
434                         break;
435                 udelay(2);
436         }
437 }
438 
439 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
440 {
441         cpu_emergency_vmxoff();
442 }
443 
444 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
445 static void emergency_vmx_disable_all(void)
446 {
447         /* Just make sure we won't change CPUs while doing this */
448         local_irq_disable();
449 
450         /*
451          * We need to disable VMX on all CPUs before rebooting, otherwise
452          * we risk hanging up the machine, because the CPU ignore INIT
453          * signals when VMX is enabled.
454          *
455          * We can't take any locks and we may be on an inconsistent
456          * state, so we use NMIs as IPIs to tell the other CPUs to disable
457          * VMX and halt.
458          *
459          * For safety, we will avoid running the nmi_shootdown_cpus()
460          * stuff unnecessarily, but we don't have a way to check
461          * if other CPUs have VMX enabled. So we will call it only if the
462          * CPU we are running on has VMX enabled.
463          *
464          * We will miss cases where VMX is not enabled on all CPUs. This
465          * shouldn't do much harm because KVM always enable VMX on all
466          * CPUs anyway. But we can miss it on the small window where KVM
467          * is still enabling VMX.
468          */
469         if (cpu_has_vmx() && cpu_vmx_enabled()) {
470                 /* Disable VMX on this CPU. */
471                 cpu_vmxoff();
472 
473                 /* Halt and disable VMX on the other CPUs */
474                 nmi_shootdown_cpus(vmxoff_nmi);
475 
476         }
477 }
478 
479 
480 void __attribute__((weak)) mach_reboot_fixups(void)
481 {
482 }
483 
484 /*
485  * To the best of our knowledge Windows compatible x86 hardware expects
486  * the following on reboot:
487  *
488  * 1) If the FADT has the ACPI reboot register flag set, try it
489  * 2) If still alive, write to the keyboard controller
490  * 3) If still alive, write to the ACPI reboot register again
491  * 4) If still alive, write to the keyboard controller again
492  * 5) If still alive, call the EFI runtime service to reboot
493  * 6) If no EFI runtime service, call the BIOS to do a reboot
494  *
495  * We default to following the same pattern. We also have
496  * two other reboot methods: 'triple fault' and 'PCI', which
497  * can be triggered via the reboot= kernel boot option or
498  * via quirks.
499  *
500  * This means that this function can never return, it can misbehave
501  * by not rebooting properly and hanging.
502  */
503 static void native_machine_emergency_restart(void)
504 {
505         int i;
506         int attempt = 0;
507         int orig_reboot_type = reboot_type;
508         unsigned short mode;
509 
510         if (reboot_emergency)
511                 emergency_vmx_disable_all();
512 
513         tboot_shutdown(TB_SHUTDOWN_REBOOT);
514 
515         /* Tell the BIOS if we want cold or warm reboot */
516         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
517         *((unsigned short *)__va(0x472)) = mode;
518 
519         for (;;) {
520                 /* Could also try the reset bit in the Hammer NB */
521                 switch (reboot_type) {
522                 case BOOT_ACPI:
523                         acpi_reboot();
524                         reboot_type = BOOT_KBD;
525                         break;
526 
527                 case BOOT_KBD:
528                         mach_reboot_fixups(); /* For board specific fixups */
529 
530                         for (i = 0; i < 10; i++) {
531                                 kb_wait();
532                                 udelay(50);
533                                 outb(0xfe, 0x64); /* Pulse reset low */
534                                 udelay(50);
535                         }
536                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
537                                 attempt = 1;
538                                 reboot_type = BOOT_ACPI;
539                         } else {
540                                 reboot_type = BOOT_EFI;
541                         }
542                         break;
543 
544                 case BOOT_EFI:
545                         efi_reboot(reboot_mode, NULL);
546                         reboot_type = BOOT_BIOS;
547                         break;
548 
549                 case BOOT_BIOS:
550                         machine_real_restart(MRR_BIOS);
551 
552                         /* We're probably dead after this, but... */
553                         reboot_type = BOOT_CF9_SAFE;
554                         break;
555 
556                 case BOOT_CF9_FORCE:
557                         port_cf9_safe = true;
558                         /* Fall through */
559 
560                 case BOOT_CF9_SAFE:
561                         if (port_cf9_safe) {
562                                 u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
563                                 u8 cf9 = inb(0xcf9) & ~reboot_code;
564                                 outb(cf9|2, 0xcf9); /* Request hard reset */
565                                 udelay(50);
566                                 /* Actually do the reset */
567                                 outb(cf9|reboot_code, 0xcf9);
568                                 udelay(50);
569                         }
570                         reboot_type = BOOT_TRIPLE;
571                         break;
572 
573                 case BOOT_TRIPLE:
574                         load_idt(&no_idt);
575                         __asm__ __volatile__("int3");
576 
577                         /* We're probably dead after this, but... */
578                         reboot_type = BOOT_KBD;
579                         break;
580                 }
581         }
582 }
583 
584 void native_machine_shutdown(void)
585 {
586         /* Stop the cpus and apics */
587 #ifdef CONFIG_X86_IO_APIC
588         /*
589          * Disabling IO APIC before local APIC is a workaround for
590          * erratum AVR31 in "Intel Atom Processor C2000 Product Family
591          * Specification Update". In this situation, interrupts that target
592          * a Logical Processor whose Local APIC is either in the process of
593          * being hardware disabled or software disabled are neither delivered
594          * nor discarded. When this erratum occurs, the processor may hang.
595          *
596          * Even without the erratum, it still makes sense to quiet IO APIC
597          * before disabling Local APIC.
598          */
599         disable_IO_APIC();
600 #endif
601 
602 #ifdef CONFIG_SMP
603         /*
604          * Stop all of the others. Also disable the local irq to
605          * not receive the per-cpu timer interrupt which may trigger
606          * scheduler's load balance.
607          */
608         local_irq_disable();
609         stop_other_cpus();
610 #endif
611 
612         lapic_shutdown();
613 
614 #ifdef CONFIG_HPET_TIMER
615         hpet_disable();
616 #endif
617 
618 #ifdef CONFIG_X86_64
619         x86_platform.iommu_shutdown();
620 #endif
621 }
622 
623 static void __machine_emergency_restart(int emergency)
624 {
625         reboot_emergency = emergency;
626         machine_ops.emergency_restart();
627 }
628 
629 static void native_machine_restart(char *__unused)
630 {
631         pr_notice("machine restart\n");
632 
633         if (!reboot_force)
634                 machine_shutdown();
635         __machine_emergency_restart(0);
636 }
637 
638 static void native_machine_halt(void)
639 {
640         /* Stop other cpus and apics */
641         machine_shutdown();
642 
643         tboot_shutdown(TB_SHUTDOWN_HALT);
644 
645         stop_this_cpu(NULL);
646 }
647 
648 static void native_machine_power_off(void)
649 {
650         if (pm_power_off) {
651                 if (!reboot_force)
652                         machine_shutdown();
653                 pm_power_off();
654         }
655         /* A fallback in case there is no PM info available */
656         tboot_shutdown(TB_SHUTDOWN_HALT);
657 }
658 
659 struct machine_ops machine_ops = {
660         .power_off = native_machine_power_off,
661         .shutdown = native_machine_shutdown,
662         .emergency_restart = native_machine_emergency_restart,
663         .restart = native_machine_restart,
664         .halt = native_machine_halt,
665 #ifdef CONFIG_KEXEC
666         .crash_shutdown = native_machine_crash_shutdown,
667 #endif
668 };
669 
670 void machine_power_off(void)
671 {
672         machine_ops.power_off();
673 }
674 
675 void machine_shutdown(void)
676 {
677         machine_ops.shutdown();
678 }
679 
680 void machine_emergency_restart(void)
681 {
682         __machine_emergency_restart(1);
683 }
684 
685 void machine_restart(char *cmd)
686 {
687         machine_ops.restart(cmd);
688 }
689 
690 void machine_halt(void)
691 {
692         machine_ops.halt();
693 }
694 
695 #ifdef CONFIG_KEXEC
696 void machine_crash_shutdown(struct pt_regs *regs)
697 {
698         machine_ops.crash_shutdown(regs);
699 }
700 #endif
701 
702 
703 #if defined(CONFIG_SMP)
704 
705 /* This keeps a track of which one is crashing cpu. */
706 static int crashing_cpu;
707 static nmi_shootdown_cb shootdown_callback;
708 
709 static atomic_t waiting_for_crash_ipi;
710 
711 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
712 {
713         int cpu;
714 
715         cpu = raw_smp_processor_id();
716 
717         /*
718          * Don't do anything if this handler is invoked on crashing cpu.
719          * Otherwise, system will completely hang. Crashing cpu can get
720          * an NMI if system was initially booted with nmi_watchdog parameter.
721          */
722         if (cpu == crashing_cpu)
723                 return NMI_HANDLED;
724         local_irq_disable();
725 
726         shootdown_callback(cpu, regs);
727 
728         atomic_dec(&waiting_for_crash_ipi);
729         /* Assume hlt works */
730         halt();
731         for (;;)
732                 cpu_relax();
733 
734         return NMI_HANDLED;
735 }
736 
737 static void smp_send_nmi_allbutself(void)
738 {
739         apic->send_IPI_allbutself(NMI_VECTOR);
740 }
741 
742 /*
743  * Halt all other CPUs, calling the specified function on each of them
744  *
745  * This function can be used to halt all other CPUs on crash
746  * or emergency reboot time. The function passed as parameter
747  * will be called inside a NMI handler on all CPUs.
748  */
749 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
750 {
751         unsigned long msecs;
752         local_irq_disable();
753 
754         /* Make a note of crashing cpu. Will be used in NMI callback. */
755         crashing_cpu = safe_smp_processor_id();
756 
757         shootdown_callback = callback;
758 
759         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
760         /* Would it be better to replace the trap vector here? */
761         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
762                                  NMI_FLAG_FIRST, "crash"))
763                 return;         /* Return what? */
764         /*
765          * Ensure the new callback function is set before sending
766          * out the NMI
767          */
768         wmb();
769 
770         smp_send_nmi_allbutself();
771 
772         msecs = 1000; /* Wait at most a second for the other cpus to stop */
773         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
774                 mdelay(1);
775                 msecs--;
776         }
777 
778         /* Leave the nmi callback set */
779 }
780 #else /* !CONFIG_SMP */
781 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
782 {
783         /* No other CPUs to shoot down */
784 }
785 #endif
786 

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