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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         {       /* Handle problems with rebooting on the iMac10,1. */
186                 .callback = set_pci_reboot,
187                 .ident = "Apple iMac10,1",
188                 .matches = {
189                     DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
190                     DMI_MATCH(DMI_PRODUCT_NAME, "iMac10,1"),
191                 },
192         },
193 
194         /* ASRock */
195         {       /* Handle problems with rebooting on ASRock Q1900DC-ITX */
196                 .callback = set_pci_reboot,
197                 .ident = "ASRock Q1900DC-ITX",
198                 .matches = {
199                         DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
200                         DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
201                 },
202         },
203 
204         /* ASUS */
205         {       /* Handle problems with rebooting on ASUS P4S800 */
206                 .callback = set_bios_reboot,
207                 .ident = "ASUS P4S800",
208                 .matches = {
209                         DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
210                         DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
211                 },
212         },
213 
214         /* Certec */
215         {       /* Handle problems with rebooting on Certec BPC600 */
216                 .callback = set_pci_reboot,
217                 .ident = "Certec BPC600",
218                 .matches = {
219                         DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
220                         DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
221                 },
222         },
223 
224         /* Dell */
225         {       /* Handle problems with rebooting on Dell DXP061 */
226                 .callback = set_bios_reboot,
227                 .ident = "Dell DXP061",
228                 .matches = {
229                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
230                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
231                 },
232         },
233         {       /* Handle problems with rebooting on Dell E520's */
234                 .callback = set_bios_reboot,
235                 .ident = "Dell E520",
236                 .matches = {
237                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
238                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
239                 },
240         },
241         {       /* Handle problems with rebooting on the Latitude E5410. */
242                 .callback = set_pci_reboot,
243                 .ident = "Dell Latitude E5410",
244                 .matches = {
245                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
246                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
247                 },
248         },
249         {       /* Handle problems with rebooting on the Latitude E5420. */
250                 .callback = set_pci_reboot,
251                 .ident = "Dell Latitude E5420",
252                 .matches = {
253                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
254                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
255                 },
256         },
257         {       /* Handle problems with rebooting on the Latitude E6320. */
258                 .callback = set_pci_reboot,
259                 .ident = "Dell Latitude E6320",
260                 .matches = {
261                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
262                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
263                 },
264         },
265         {       /* Handle problems with rebooting on the Latitude E6420. */
266                 .callback = set_pci_reboot,
267                 .ident = "Dell Latitude E6420",
268                 .matches = {
269                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
270                         DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
271                 },
272         },
273         {       /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
274                 .callback = set_bios_reboot,
275                 .ident = "Dell OptiPlex 330",
276                 .matches = {
277                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
278                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
279                         DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
280                 },
281         },
282         {       /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
283                 .callback = set_bios_reboot,
284                 .ident = "Dell OptiPlex 360",
285                 .matches = {
286                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
287                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
288                         DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
289                 },
290         },
291         {       /* Handle problems with rebooting on Dell Optiplex 745's SFF */
292                 .callback = set_bios_reboot,
293                 .ident = "Dell OptiPlex 745",
294                 .matches = {
295                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
296                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
297                 },
298         },
299         {       /* Handle problems with rebooting on Dell Optiplex 745's DFF */
300                 .callback = set_bios_reboot,
301                 .ident = "Dell OptiPlex 745",
302                 .matches = {
303                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
304                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
305                         DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
306                 },
307         },
308         {       /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
309                 .callback = set_bios_reboot,
310                 .ident = "Dell OptiPlex 745",
311                 .matches = {
312                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
313                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
314                         DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
315                 },
316         },
317         {       /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
318                 .callback = set_bios_reboot,
319                 .ident = "Dell OptiPlex 760",
320                 .matches = {
321                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
322                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
323                         DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
324                 },
325         },
326         {       /* Handle problems with rebooting on the OptiPlex 990. */
327                 .callback = set_pci_reboot,
328                 .ident = "Dell OptiPlex 990",
329                 .matches = {
330                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
331                         DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
332                 },
333         },
334         {       /* Handle problems with rebooting on Dell 300's */
335                 .callback = set_bios_reboot,
336                 .ident = "Dell PowerEdge 300",
337                 .matches = {
338                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
339                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
340                 },
341         },
342         {       /* Handle problems with rebooting on Dell 1300's */
343                 .callback = set_bios_reboot,
344                 .ident = "Dell PowerEdge 1300",
345                 .matches = {
346                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
347                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
348                 },
349         },
350         {       /* Handle problems with rebooting on Dell 2400's */
351                 .callback = set_bios_reboot,
352                 .ident = "Dell PowerEdge 2400",
353                 .matches = {
354                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
355                         DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
356                 },
357         },
358         {       /* Handle problems with rebooting on the Dell PowerEdge C6100. */
359                 .callback = set_pci_reboot,
360                 .ident = "Dell PowerEdge C6100",
361                 .matches = {
362                         DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
363                         DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
364                 },
365         },
366         {       /* Handle problems with rebooting on the Precision M6600. */
367                 .callback = set_pci_reboot,
368                 .ident = "Dell Precision M6600",
369                 .matches = {
370                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
371                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
372                 },
373         },
374         {       /* Handle problems with rebooting on Dell T5400's */
375                 .callback = set_bios_reboot,
376                 .ident = "Dell Precision T5400",
377                 .matches = {
378                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
379                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
380                 },
381         },
382         {       /* Handle problems with rebooting on Dell T7400's */
383                 .callback = set_bios_reboot,
384                 .ident = "Dell Precision T7400",
385                 .matches = {
386                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
387                         DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
388                 },
389         },
390         {       /* Handle problems with rebooting on Dell XPS710 */
391                 .callback = set_bios_reboot,
392                 .ident = "Dell XPS710",
393                 .matches = {
394                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
395                         DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
396                 },
397         },
398 
399         /* Hewlett-Packard */
400         {       /* Handle problems with rebooting on HP laptops */
401                 .callback = set_bios_reboot,
402                 .ident = "HP Compaq Laptop",
403                 .matches = {
404                         DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
405                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
406                 },
407         },
408 
409         /* Sony */
410         {       /* Handle problems with rebooting on Sony VGN-Z540N */
411                 .callback = set_bios_reboot,
412                 .ident = "Sony VGN-Z540N",
413                 .matches = {
414                         DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
415                         DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
416                 },
417         },
418 
419         { }
420 };
421 
422 static int __init reboot_init(void)
423 {
424         int rv;
425 
426         /*
427          * Only do the DMI check if reboot_type hasn't been overridden
428          * on the command line
429          */
430         if (!reboot_default)
431                 return 0;
432 
433         /*
434          * The DMI quirks table takes precedence. If no quirks entry
435          * matches and the ACPI Hardware Reduced bit is set, force EFI
436          * reboot.
437          */
438         rv = dmi_check_system(reboot_dmi_table);
439 
440         if (!rv && efi_reboot_required())
441                 reboot_type = BOOT_EFI;
442 
443         return 0;
444 }
445 core_initcall(reboot_init);
446 
447 static inline void kb_wait(void)
448 {
449         int i;
450 
451         for (i = 0; i < 0x10000; i++) {
452                 if ((inb(0x64) & 0x02) == 0)
453                         break;
454                 udelay(2);
455         }
456 }
457 
458 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
459 {
460         cpu_emergency_vmxoff();
461 }
462 
463 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
464 static void emergency_vmx_disable_all(void)
465 {
466         /* Just make sure we won't change CPUs while doing this */
467         local_irq_disable();
468 
469         /*
470          * We need to disable VMX on all CPUs before rebooting, otherwise
471          * we risk hanging up the machine, because the CPU ignore INIT
472          * signals when VMX is enabled.
473          *
474          * We can't take any locks and we may be on an inconsistent
475          * state, so we use NMIs as IPIs to tell the other CPUs to disable
476          * VMX and halt.
477          *
478          * For safety, we will avoid running the nmi_shootdown_cpus()
479          * stuff unnecessarily, but we don't have a way to check
480          * if other CPUs have VMX enabled. So we will call it only if the
481          * CPU we are running on has VMX enabled.
482          *
483          * We will miss cases where VMX is not enabled on all CPUs. This
484          * shouldn't do much harm because KVM always enable VMX on all
485          * CPUs anyway. But we can miss it on the small window where KVM
486          * is still enabling VMX.
487          */
488         if (cpu_has_vmx() && cpu_vmx_enabled()) {
489                 /* Disable VMX on this CPU. */
490                 cpu_vmxoff();
491 
492                 /* Halt and disable VMX on the other CPUs */
493                 nmi_shootdown_cpus(vmxoff_nmi);
494 
495         }
496 }
497 
498 
499 void __attribute__((weak)) mach_reboot_fixups(void)
500 {
501 }
502 
503 /*
504  * To the best of our knowledge Windows compatible x86 hardware expects
505  * the following on reboot:
506  *
507  * 1) If the FADT has the ACPI reboot register flag set, try it
508  * 2) If still alive, write to the keyboard controller
509  * 3) If still alive, write to the ACPI reboot register again
510  * 4) If still alive, write to the keyboard controller again
511  * 5) If still alive, call the EFI runtime service to reboot
512  * 6) If no EFI runtime service, call the BIOS to do a reboot
513  *
514  * We default to following the same pattern. We also have
515  * two other reboot methods: 'triple fault' and 'PCI', which
516  * can be triggered via the reboot= kernel boot option or
517  * via quirks.
518  *
519  * This means that this function can never return, it can misbehave
520  * by not rebooting properly and hanging.
521  */
522 static void native_machine_emergency_restart(void)
523 {
524         int i;
525         int attempt = 0;
526         int orig_reboot_type = reboot_type;
527         unsigned short mode;
528 
529         if (reboot_emergency)
530                 emergency_vmx_disable_all();
531 
532         tboot_shutdown(TB_SHUTDOWN_REBOOT);
533 
534         /* Tell the BIOS if we want cold or warm reboot */
535         mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
536         *((unsigned short *)__va(0x472)) = mode;
537 
538         for (;;) {
539                 /* Could also try the reset bit in the Hammer NB */
540                 switch (reboot_type) {
541                 case BOOT_ACPI:
542                         acpi_reboot();
543                         reboot_type = BOOT_KBD;
544                         break;
545 
546                 case BOOT_KBD:
547                         mach_reboot_fixups(); /* For board specific fixups */
548 
549                         for (i = 0; i < 10; i++) {
550                                 kb_wait();
551                                 udelay(50);
552                                 outb(0xfe, 0x64); /* Pulse reset low */
553                                 udelay(50);
554                         }
555                         if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
556                                 attempt = 1;
557                                 reboot_type = BOOT_ACPI;
558                         } else {
559                                 reboot_type = BOOT_EFI;
560                         }
561                         break;
562 
563                 case BOOT_EFI:
564                         efi_reboot(reboot_mode, NULL);
565                         reboot_type = BOOT_BIOS;
566                         break;
567 
568                 case BOOT_BIOS:
569                         machine_real_restart(MRR_BIOS);
570 
571                         /* We're probably dead after this, but... */
572                         reboot_type = BOOT_CF9_SAFE;
573                         break;
574 
575                 case BOOT_CF9_FORCE:
576                         port_cf9_safe = true;
577                         /* Fall through */
578 
579                 case BOOT_CF9_SAFE:
580                         if (port_cf9_safe) {
581                                 u8 reboot_code = reboot_mode == REBOOT_WARM ?  0x06 : 0x0E;
582                                 u8 cf9 = inb(0xcf9) & ~reboot_code;
583                                 outb(cf9|2, 0xcf9); /* Request hard reset */
584                                 udelay(50);
585                                 /* Actually do the reset */
586                                 outb(cf9|reboot_code, 0xcf9);
587                                 udelay(50);
588                         }
589                         reboot_type = BOOT_TRIPLE;
590                         break;
591 
592                 case BOOT_TRIPLE:
593                         load_idt(&no_idt);
594                         __asm__ __volatile__("int3");
595 
596                         /* We're probably dead after this, but... */
597                         reboot_type = BOOT_KBD;
598                         break;
599                 }
600         }
601 }
602 
603 void native_machine_shutdown(void)
604 {
605         /* Stop the cpus and apics */
606 #ifdef CONFIG_X86_IO_APIC
607         /*
608          * Disabling IO APIC before local APIC is a workaround for
609          * erratum AVR31 in "Intel Atom Processor C2000 Product Family
610          * Specification Update". In this situation, interrupts that target
611          * a Logical Processor whose Local APIC is either in the process of
612          * being hardware disabled or software disabled are neither delivered
613          * nor discarded. When this erratum occurs, the processor may hang.
614          *
615          * Even without the erratum, it still makes sense to quiet IO APIC
616          * before disabling Local APIC.
617          */
618         disable_IO_APIC();
619 #endif
620 
621 #ifdef CONFIG_SMP
622         /*
623          * Stop all of the others. Also disable the local irq to
624          * not receive the per-cpu timer interrupt which may trigger
625          * scheduler's load balance.
626          */
627         local_irq_disable();
628         stop_other_cpus();
629 #endif
630 
631         lapic_shutdown();
632 
633 #ifdef CONFIG_HPET_TIMER
634         hpet_disable();
635 #endif
636 
637 #ifdef CONFIG_X86_64
638         x86_platform.iommu_shutdown();
639 #endif
640 }
641 
642 static void __machine_emergency_restart(int emergency)
643 {
644         reboot_emergency = emergency;
645         machine_ops.emergency_restart();
646 }
647 
648 static void native_machine_restart(char *__unused)
649 {
650         pr_notice("machine restart\n");
651 
652         if (!reboot_force)
653                 machine_shutdown();
654         __machine_emergency_restart(0);
655 }
656 
657 static void native_machine_halt(void)
658 {
659         /* Stop other cpus and apics */
660         machine_shutdown();
661 
662         tboot_shutdown(TB_SHUTDOWN_HALT);
663 
664         stop_this_cpu(NULL);
665 }
666 
667 static void native_machine_power_off(void)
668 {
669         if (pm_power_off) {
670                 if (!reboot_force)
671                         machine_shutdown();
672                 pm_power_off();
673         }
674         /* A fallback in case there is no PM info available */
675         tboot_shutdown(TB_SHUTDOWN_HALT);
676 }
677 
678 struct machine_ops machine_ops = {
679         .power_off = native_machine_power_off,
680         .shutdown = native_machine_shutdown,
681         .emergency_restart = native_machine_emergency_restart,
682         .restart = native_machine_restart,
683         .halt = native_machine_halt,
684 #ifdef CONFIG_KEXEC_CORE
685         .crash_shutdown = native_machine_crash_shutdown,
686 #endif
687 };
688 
689 void machine_power_off(void)
690 {
691         machine_ops.power_off();
692 }
693 
694 void machine_shutdown(void)
695 {
696         machine_ops.shutdown();
697 }
698 
699 void machine_emergency_restart(void)
700 {
701         __machine_emergency_restart(1);
702 }
703 
704 void machine_restart(char *cmd)
705 {
706         machine_ops.restart(cmd);
707 }
708 
709 void machine_halt(void)
710 {
711         machine_ops.halt();
712 }
713 
714 #ifdef CONFIG_KEXEC_CORE
715 void machine_crash_shutdown(struct pt_regs *regs)
716 {
717         machine_ops.crash_shutdown(regs);
718 }
719 #endif
720 
721 
722 #if defined(CONFIG_SMP)
723 
724 /* This keeps a track of which one is crashing cpu. */
725 static int crashing_cpu;
726 static nmi_shootdown_cb shootdown_callback;
727 
728 static atomic_t waiting_for_crash_ipi;
729 static int crash_ipi_issued;
730 
731 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
732 {
733         int cpu;
734 
735         cpu = raw_smp_processor_id();
736 
737         /*
738          * Don't do anything if this handler is invoked on crashing cpu.
739          * Otherwise, system will completely hang. Crashing cpu can get
740          * an NMI if system was initially booted with nmi_watchdog parameter.
741          */
742         if (cpu == crashing_cpu)
743                 return NMI_HANDLED;
744         local_irq_disable();
745 
746         shootdown_callback(cpu, regs);
747 
748         atomic_dec(&waiting_for_crash_ipi);
749         /* Assume hlt works */
750         halt();
751         for (;;)
752                 cpu_relax();
753 
754         return NMI_HANDLED;
755 }
756 
757 static void smp_send_nmi_allbutself(void)
758 {
759         apic->send_IPI_allbutself(NMI_VECTOR);
760 }
761 
762 /*
763  * Halt all other CPUs, calling the specified function on each of them
764  *
765  * This function can be used to halt all other CPUs on crash
766  * or emergency reboot time. The function passed as parameter
767  * will be called inside a NMI handler on all CPUs.
768  */
769 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
770 {
771         unsigned long msecs;
772         local_irq_disable();
773 
774         /* Make a note of crashing cpu. Will be used in NMI callback. */
775         crashing_cpu = safe_smp_processor_id();
776 
777         shootdown_callback = callback;
778 
779         atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
780         /* Would it be better to replace the trap vector here? */
781         if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
782                                  NMI_FLAG_FIRST, "crash"))
783                 return;         /* Return what? */
784         /*
785          * Ensure the new callback function is set before sending
786          * out the NMI
787          */
788         wmb();
789 
790         smp_send_nmi_allbutself();
791 
792         /* Kick CPUs looping in NMI context. */
793         WRITE_ONCE(crash_ipi_issued, 1);
794 
795         msecs = 1000; /* Wait at most a second for the other cpus to stop */
796         while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
797                 mdelay(1);
798                 msecs--;
799         }
800 
801         /* Leave the nmi callback set */
802 }
803 
804 /*
805  * Check if the crash dumping IPI got issued and if so, call its callback
806  * directly. This function is used when we have already been in NMI handler.
807  * It doesn't return.
808  */
809 void run_crash_ipi_callback(struct pt_regs *regs)
810 {
811         if (crash_ipi_issued)
812                 crash_nmi_callback(0, regs);
813 }
814 
815 /* Override the weak function in kernel/panic.c */
816 void nmi_panic_self_stop(struct pt_regs *regs)
817 {
818         while (1) {
819                 /* If no CPU is preparing crash dump, we simply loop here. */
820                 run_crash_ipi_callback(regs);
821                 cpu_relax();
822         }
823 }
824 
825 #else /* !CONFIG_SMP */
826 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
827 {
828         /* No other CPUs to shoot down */
829 }
830 
831 void run_crash_ipi_callback(struct pt_regs *regs)
832 {
833 }
834 #endif
835 

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