Version:  2.0.40 2.2.26 2.4.37 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 3.19

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/io_apic.h>
 16 #include <asm/desc.h>
 17 #include <asm/hpet.h>
 18 #include <asm/pgtable.h>
 19 #include <asm/proto.h>
 20 #include <asm/reboot_fixups.h>
 21 #include <asm/reboot.h>
 22 #include <asm/pci_x86.h>
 23 #include <asm/virtext.h>
 24 #include <asm/cpu.h>
 25 #include <asm/nmi.h>
 26 #include <asm/smp.h>
 27 
 28 #include <linux/ctype.h>
 29 #include <linux/mc146818rtc.h>
 30 #include <asm/realmode.h>
 31 #include <asm/x86_init.h>
 32 #include <asm/efi.h>
 33 
 34 /*
 35  * Power off function, if any
 36  */
 37 void (*pm_power_off)(void);
 38 EXPORT_SYMBOL(pm_power_off);
 39 
 40 static const struct desc_ptr no_idt = {};
 41 
 42 /*
 43  * This is set if we need to go through the 'emergency' path.
 44  * When machine_emergency_restart() is called, we may be on
 45  * an inconsistent state and won't be able to do a clean cleanup
 46  */
 47 static int reboot_emergency;
 48 
 49 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
 50 bool port_cf9_safe = false;
 51 
 52 /*
 53  * Reboot options and system auto-detection code provided by
 54  * Dell Inc. so their systems "just work". :-)
 55  */
 56 
 57 /*
 58  * Some machines require the "reboot=b" or "reboot=k"  commandline options,
 59  * this quirk makes that automatic.
 60  */
 61 static int __init set_bios_reboot(const struct dmi_system_id *d)
 62 {
 63         if (reboot_type != BOOT_BIOS) {
 64                 reboot_type = BOOT_BIOS;
 65                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
 66                         d->ident, "BIOS");
 67         }
 68         return 0;
 69 }
 70 
 71 void __noreturn machine_real_restart(unsigned int type)
 72 {
 73         local_irq_disable();
 74 
 75         /*
 76          * Write zero to CMOS register number 0x0f, which the BIOS POST
 77          * routine will recognize as telling it to do a proper reboot.  (Well
 78          * that's what this book in front of me says -- it may only apply to
 79          * the Phoenix BIOS though, it's not clear).  At the same time,
 80          * disable NMIs by setting the top bit in the CMOS address register,
 81          * as we're about to do peculiar things to the CPU.  I'm not sure if
 82          * `outb_p' is needed instead of just `outb'.  Use it to be on the
 83          * safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
 84          */
 85         spin_lock(&rtc_lock);
 86         CMOS_WRITE(0x00, 0x8f);
 87         spin_unlock(&rtc_lock);
 88 
 89         /*
 90          * Switch back to the initial page table.
 91          */
 92 #ifdef CONFIG_X86_32
 93         load_cr3(initial_page_table);
 94 #else
 95         write_cr3(real_mode_header->trampoline_pgd);
 96 #endif
 97 
 98         /* Jump to the identity-mapped low memory code */
 99 #ifdef CONFIG_X86_32
100         asm volatile("jmpl *%0" : :
101                      "rm" (real_mode_header->machine_real_restart_asm),
102                      "a" (type));
103 #else
104         asm volatile("ljmpl *%0" : :
105                      "m" (real_mode_header->machine_real_restart_asm),
106                      "D" (type));
107 #endif
108         unreachable();
109 }
110 #ifdef CONFIG_APM_MODULE
111 EXPORT_SYMBOL(machine_real_restart);
112 #endif
113 
114 /*
115  * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
116  */
117 static int __init set_pci_reboot(const struct dmi_system_id *d)
118 {
119         if (reboot_type != BOOT_CF9_FORCE) {
120                 reboot_type = BOOT_CF9_FORCE;
121                 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
122                         d->ident, "PCI");
123         }
124         return 0;
125 }
126 
127 static int __init set_kbd_reboot(const struct dmi_system_id *d)
128 {
129         if (reboot_type != BOOT_KBD) {
130                 reboot_type = BOOT_KBD;
131                 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
132                         d->ident, "KBD");
133         }
134         return 0;
135 }
136 
137 /*
138  * This is a single dmi_table handling all reboot quirks.
139  */
140 static struct dmi_system_id __initdata reboot_dmi_table[] = {
141 
142         /* Acer */
143         {       /* Handle reboot issue on Acer Aspire one */
144                 .callback = set_kbd_reboot,
145                 .ident = "Acer Aspire One A110",
146                 .matches = {
147                         DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
148                         DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
149                 },
150         },
151 
152         /* Apple */
153         {       /* Handle problems with rebooting on Apple MacBook5 */
154                 .callback = set_pci_reboot,
155                 .ident = "Apple MacBook5",
156                 .matches = {
157                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
158                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
159                 },
160         },
161         {       /* Handle problems with rebooting on Apple MacBookPro5 */
162                 .callback = set_pci_reboot,
163                 .ident = "Apple MacBookPro5",
164                 .matches = {
165                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
166                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
167                 },
168         },
169         {       /* Handle problems with rebooting on Apple Macmini3,1 */
170                 .callback = set_pci_reboot,
171                 .ident = "Apple Macmini3,1",
172                 .matches = {
173                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
174                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
175                 },
176         },
177         {       /* Handle problems with rebooting on the iMac9,1. */
178                 .callback = set_pci_reboot,
179                 .ident = "Apple iMac9,1",
180                 .matches = {
181                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
182                         DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
183                 },
184         },
185 
186         /* ASUS */
187         {       /* Handle problems with rebooting on ASUS P4S800 */
188                 .callback = set_bios_reboot,
189                 .ident = "ASUS P4S800",
190                 .matches = {
191                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
192                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
193                 },
194         },
195 
196         /* Certec */
197         {       /* Handle problems with rebooting on Certec BPC600 */
198                 .callback = set_pci_reboot,
199                 .ident = "Certec BPC600",
200                 .matches = {
201                         DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
202                         DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
203                 },
204         },
205 
206         /* Dell */
207         {       /* Handle problems with rebooting on Dell DXP061 */
208                 .callback = set_bios_reboot,
209                 .ident = "Dell DXP061",
210                 .matches = {
211                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
212                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
213                 },
214         },
215         {       /* Handle problems with rebooting on Dell E520's */
216                 .callback = set_bios_reboot,
217                 .ident = "Dell E520",
218                 .matches = {
219                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
220                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
221                 },
222         },
223         {       /* Handle problems with rebooting on the Latitude E5410. */
224                 .callback = set_pci_reboot,
225                 .ident = "Dell Latitude E5410",
226                 .matches = {
227                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
228                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
229                 },
230         },
231         {       /* Handle problems with rebooting on the Latitude E5420. */
232                 .callback = set_pci_reboot,
233                 .ident = "Dell Latitude E5420",
234                 .matches = {
235                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
236                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
237                 },
238         },
239         {       /* Handle problems with rebooting on the Latitude E6320. */
240                 .callback = set_pci_reboot,
241                 .ident = "Dell Latitude E6320",
242                 .matches = {
243                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
244                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
245                 },
246         },
247         {       /* Handle problems with rebooting on the Latitude E6420. */
248                 .callback = set_pci_reboot,
249                 .ident = "Dell Latitude E6420",
250                 .matches = {
251                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
252                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
253                 },
254         },
255         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
256                 .callback = set_bios_reboot,
257                 .ident = "Dell OptiPlex 330",
258                 .matches = {
259                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
260                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
261                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
262                 },
263         },
264         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
265                 .callback = set_bios_reboot,
266                 .ident = "Dell OptiPlex 360",
267                 .matches = {
268                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
269                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
270                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
271                 },
272         },
273         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
274                 .callback = set_bios_reboot,
275                 .ident = "Dell OptiPlex 745",
276                 .matches = {
277                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
278                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
279                 },
280         },
281         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
282                 .callback = set_bios_reboot,
283                 .ident = "Dell OptiPlex 745",
284                 .matches = {
285                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
286                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
287                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
288                 },
289         },
290         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
291                 .callback = set_bios_reboot,
292                 .ident = "Dell OptiPlex 745",
293                 .matches = {
294                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
295                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
296                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
297                 },
298         },
299         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
300                 .callback = set_bios_reboot,
301                 .ident = "Dell OptiPlex 760",
302                 .matches = {
303                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
304                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
305                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
306                 },
307         },
308         {       /* Handle problems with rebooting on the OptiPlex 990. */
309                 .callback = set_pci_reboot,
310                 .ident = "Dell OptiPlex 990",
311                 .matches = {
312                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
313                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
314                 },
315         },
316         {       /* Handle problems with rebooting on Dell 300's */
317                 .callback = set_bios_reboot,
318                 .ident = "Dell PowerEdge 300",
319                 .matches = {
320                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
321                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
322                 },
323         },
324         {       /* Handle problems with rebooting on Dell 1300's */
325                 .callback = set_bios_reboot,
326                 .ident = "Dell PowerEdge 1300",
327                 .matches = {
328                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
329                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
330                 },
331         },
332         {       /* Handle problems with rebooting on Dell 2400's */
333                 .callback = set_bios_reboot,
334                 .ident = "Dell PowerEdge 2400",
335                 .matches = {
336                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
337                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
338                 },
339         },
340         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
341                 .callback = set_pci_reboot,
342                 .ident = "Dell PowerEdge C6100",
343                 .matches = {
344                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
345                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
346                 },
347         },
348         {       /* Handle problems with rebooting on the Precision M6600. */
349                 .callback = set_pci_reboot,
350                 .ident = "Dell Precision M6600",
351                 .matches = {
352                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
353                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
354                 },
355         },
356         {       /* Handle problems with rebooting on Dell T5400's */
357                 .callback = set_bios_reboot,
358                 .ident = "Dell Precision T5400",
359                 .matches = {
360                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
361                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
362                 },
363         },
364         {       /* Handle problems with rebooting on Dell T7400's */
365                 .callback = set_bios_reboot,
366                 .ident = "Dell Precision T7400",
367                 .matches = {
368                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
369                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
370                 },
371         },
372         {       /* Handle problems with rebooting on Dell XPS710 */
373                 .callback = set_bios_reboot,
374                 .ident = "Dell XPS710",
375                 .matches = {
376                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
377                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
378                 },
379         },
380 
381         /* Hewlett-Packard */
382         {       /* Handle problems with rebooting on HP laptops */
383                 .callback = set_bios_reboot,
384                 .ident = "HP Compaq Laptop",
385                 .matches = {
386                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
387                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
388                 },
389         },
390 
391         /* Sony */
392         {       /* Handle problems with rebooting on Sony VGN-Z540N */
393                 .callback = set_bios_reboot,
394                 .ident = "Sony VGN-Z540N",
395                 .matches = {
396                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
397                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
398                 },
399         },
400 
401         { }
402 };
403 
404 static int __init reboot_init(void)
405 {
406         int rv;
407 
408         /*
409          * Only do the DMI check if reboot_type hasn't been overridden
410          * on the command line
411          */
412         if (!reboot_default)
413                 return 0;
414 
415         /*
416          * The DMI quirks table takes precedence. If no quirks entry
417          * matches and the ACPI Hardware Reduced bit is set, force EFI
418          * reboot.
419          */
420         rv = dmi_check_system(reboot_dmi_table);
421 
422         if (!rv && efi_reboot_required())
423                 reboot_type = BOOT_EFI;
424 
425         return 0;
426 }
427 core_initcall(reboot_init);
428 
429 static inline void kb_wait(void)
430 {
431         int i;
432 
433         for (i = 0; i < 0x10000; i++) {
434                 if ((inb(0x64) & 0x02) == 0)
435                         break;
436                 udelay(2);
437         }
438 }
439 
440 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
441 {
442         cpu_emergency_vmxoff();
443 }
444 
445 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
446 static void emergency_vmx_disable_all(void)
447 {
448         /* Just make sure we won't change CPUs while doing this */
449         local_irq_disable();
450 
451         /*
452          * We need to disable VMX on all CPUs before rebooting, otherwise
453          * we risk hanging up the machine, because the CPU ignore INIT
454          * signals when VMX is enabled.
455          *
456          * We can't take any locks and we may be on an inconsistent
457          * state, so we use NMIs as IPIs to tell the other CPUs to disable
458          * VMX and halt.
459          *
460          * For safety, we will avoid running the nmi_shootdown_cpus()
461          * stuff unnecessarily, but we don't have a way to check
462          * if other CPUs have VMX enabled. So we will call it only if the
463          * CPU we are running on has VMX enabled.
464          *
465          * We will miss cases where VMX is not enabled on all CPUs. This
466          * shouldn't do much harm because KVM always enable VMX on all
467          * CPUs anyway. But we can miss it on the small window where KVM
468          * is still enabling VMX.
469          */
470         if (cpu_has_vmx() && cpu_vmx_enabled()) {
471                 /* Disable VMX on this CPU. */
472                 cpu_vmxoff();
473 
474                 /* Halt and disable VMX on the other CPUs */
475                 nmi_shootdown_cpus(vmxoff_nmi);
476 
477         }
478 }
479 
480 
481 void __attribute__((weak)) mach_reboot_fixups(void)
482 {
483 }
484 
485 /*
486  * To the best of our knowledge Windows compatible x86 hardware expects
487  * the following on reboot:
488  *
489  * 1) If the FADT has the ACPI reboot register flag set, try it
490  * 2) If still alive, write to the keyboard controller
491  * 3) If still alive, write to the ACPI reboot register again
492  * 4) If still alive, write to the keyboard controller again
493  * 5) If still alive, call the EFI runtime service to reboot
494  * 6) If no EFI runtime service, call the BIOS to do a reboot
495  *
496  * We default to following the same pattern. We also have
497  * two other reboot methods: 'triple fault' and 'PCI', which
498  * can be triggered via the reboot= kernel boot option or
499  * via quirks.
500  *
501  * This means that this function can never return, it can misbehave
502  * by not rebooting properly and hanging.
503  */
504 static void native_machine_emergency_restart(void)
505 {
506         int i;
507         int attempt = 0;
508         int orig_reboot_type = reboot_type;
509         unsigned short mode;
510 
511         if (reboot_emergency)
512                 emergency_vmx_disable_all();
513 
514         tboot_shutdown(TB_SHUTDOWN_REBOOT);
515 
516         /* Tell the BIOS if we want cold or warm reboot */
517         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
518         *((unsigned short *)__va(0x472)) = mode;
519 
520         for (;;) {
521                 /* Could also try the reset bit in the Hammer NB */
522                 switch (reboot_type) {
523                 case BOOT_ACPI:
524                         acpi_reboot();
525                         reboot_type = BOOT_KBD;
526                         break;
527 
528                 case BOOT_KBD:
529                         mach_reboot_fixups(); /* For board specific fixups */
530 
531                         for (i = 0; i < 10; i++) {
532                                 kb_wait();
533                                 udelay(50);
534                                 outb(0xfe, 0x64); /* Pulse reset low */
535                                 udelay(50);
536                         }
537                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
538                                 attempt = 1;
539                                 reboot_type = BOOT_ACPI;
540                         } else {
541                                 reboot_type = BOOT_EFI;
542                         }
543                         break;
544 
545                 case BOOT_EFI:
546                         efi_reboot(reboot_mode, NULL);
547                         reboot_type = BOOT_BIOS;
548                         break;
549 
550                 case BOOT_BIOS:
551                         machine_real_restart(MRR_BIOS);
552 
553                         /* We're probably dead after this, but... */
554                         reboot_type = BOOT_CF9_SAFE;
555                         break;
556 
557                 case BOOT_CF9_FORCE:
558                         port_cf9_safe = true;
559                         /* Fall through */
560 
561                 case BOOT_CF9_SAFE:
562                         if (port_cf9_safe) {
563                                 u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
564                                 u8 cf9 = inb(0xcf9) & ~reboot_code;
565                                 outb(cf9|2, 0xcf9); /* Request hard reset */
566                                 udelay(50);
567                                 /* Actually do the reset */
568                                 outb(cf9|reboot_code, 0xcf9);
569                                 udelay(50);
570                         }
571                         reboot_type = BOOT_TRIPLE;
572                         break;
573 
574                 case BOOT_TRIPLE:
575                         load_idt(&no_idt);
576                         __asm__ __volatile__("int3");
577 
578                         /* We're probably dead after this, but... */
579                         reboot_type = BOOT_KBD;
580                         break;
581                 }
582         }
583 }
584 
585 void native_machine_shutdown(void)
586 {
587         /* Stop the cpus and apics */
588 #ifdef CONFIG_X86_IO_APIC
589         /*
590          * Disabling IO APIC before local APIC is a workaround for
591          * erratum AVR31 in "Intel Atom Processor C2000 Product Family
592          * Specification Update". In this situation, interrupts that target
593          * a Logical Processor whose Local APIC is either in the process of
594          * being hardware disabled or software disabled are neither delivered
595          * nor discarded. When this erratum occurs, the processor may hang.
596          *
597          * Even without the erratum, it still makes sense to quiet IO APIC
598          * before disabling Local APIC.
599          */
600         disable_IO_APIC();
601 #endif
602 
603 #ifdef CONFIG_SMP
604         /*
605          * Stop all of the others. Also disable the local irq to
606          * not receive the per-cpu timer interrupt which may trigger
607          * scheduler's load balance.
608          */
609         local_irq_disable();
610         stop_other_cpus();
611 #endif
612 
613         lapic_shutdown();
614 
615 #ifdef CONFIG_HPET_TIMER
616         hpet_disable();
617 #endif
618 
619 #ifdef CONFIG_X86_64
620         x86_platform.iommu_shutdown();
621 #endif
622 }
623 
624 static void __machine_emergency_restart(int emergency)
625 {
626         reboot_emergency = emergency;
627         machine_ops.emergency_restart();
628 }
629 
630 static void native_machine_restart(char *__unused)
631 {
632         pr_notice("machine restart\n");
633 
634         if (!reboot_force)
635                 machine_shutdown();
636         __machine_emergency_restart(0);
637 }
638 
639 static void native_machine_halt(void)
640 {
641         /* Stop other cpus and apics */
642         machine_shutdown();
643 
644         tboot_shutdown(TB_SHUTDOWN_HALT);
645 
646         stop_this_cpu(NULL);
647 }
648 
649 static void native_machine_power_off(void)
650 {
651         if (pm_power_off) {
652                 if (!reboot_force)
653                         machine_shutdown();
654                 pm_power_off();
655         }
656         /* A fallback in case there is no PM info available */
657         tboot_shutdown(TB_SHUTDOWN_HALT);
658 }
659 
660 struct machine_ops machine_ops = {
661         .power_off = native_machine_power_off,
662         .shutdown = native_machine_shutdown,
663         .emergency_restart = native_machine_emergency_restart,
664         .restart = native_machine_restart,
665         .halt = native_machine_halt,
666 #ifdef CONFIG_KEXEC
667         .crash_shutdown = native_machine_crash_shutdown,
668 #endif
669 };
670 
671 void machine_power_off(void)
672 {
673         machine_ops.power_off();
674 }
675 
676 void machine_shutdown(void)
677 {
678         machine_ops.shutdown();
679 }
680 
681 void machine_emergency_restart(void)
682 {
683         __machine_emergency_restart(1);
684 }
685 
686 void machine_restart(char *cmd)
687 {
688         machine_ops.restart(cmd);
689 }
690 
691 void machine_halt(void)
692 {
693         machine_ops.halt();
694 }
695 
696 #ifdef CONFIG_KEXEC
697 void machine_crash_shutdown(struct pt_regs *regs)
698 {
699         machine_ops.crash_shutdown(regs);
700 }
701 #endif
702 
703 
704 #if defined(CONFIG_SMP)
705 
706 /* This keeps a track of which one is crashing cpu. */
707 static int crashing_cpu;
708 static nmi_shootdown_cb shootdown_callback;
709 
710 static atomic_t waiting_for_crash_ipi;
711 
712 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
713 {
714         int cpu;
715 
716         cpu = raw_smp_processor_id();
717 
718         /*
719          * Don't do anything if this handler is invoked on crashing cpu.
720          * Otherwise, system will completely hang. Crashing cpu can get
721          * an NMI if system was initially booted with nmi_watchdog parameter.
722          */
723         if (cpu == crashing_cpu)
724                 return NMI_HANDLED;
725         local_irq_disable();
726 
727         shootdown_callback(cpu, regs);
728 
729         atomic_dec(&waiting_for_crash_ipi);
730         /* Assume hlt works */
731         halt();
732         for (;;)
733                 cpu_relax();
734 
735         return NMI_HANDLED;
736 }
737 
738 static void smp_send_nmi_allbutself(void)
739 {
740         apic->send_IPI_allbutself(NMI_VECTOR);
741 }
742 
743 /*
744  * Halt all other CPUs, calling the specified function on each of them
745  *
746  * This function can be used to halt all other CPUs on crash
747  * or emergency reboot time. The function passed as parameter
748  * will be called inside a NMI handler on all CPUs.
749  */
750 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
751 {
752         unsigned long msecs;
753         local_irq_disable();
754 
755         /* Make a note of crashing cpu. Will be used in NMI callback. */
756         crashing_cpu = safe_smp_processor_id();
757 
758         shootdown_callback = callback;
759 
760         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
761         /* Would it be better to replace the trap vector here? */
762         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
763                                  NMI_FLAG_FIRST, "crash"))
764                 return;         /* Return what? */
765         /*
766          * Ensure the new callback function is set before sending
767          * out the NMI
768          */
769         wmb();
770 
771         smp_send_nmi_allbutself();
772 
773         msecs = 1000; /* Wait at most a second for the other cpus to stop */
774         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
775                 mdelay(1);
776                 msecs--;
777         }
778 
779         /* Leave the nmi callback set */
780 }
781 #else /* !CONFIG_SMP */
782 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
783 {
784         /* No other CPUs to shoot down */
785 }
786 #endif
787 

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