1 // SPDX-License-Identifier: GPL-2.0
2 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
4 #include <linux/export.h>
5 #include <linux/reboot.h>
6 #include <linux/init.h>
10 #include <linux/sched.h>
11 #include <linux/tboot.h>
12 #include <linux/delay.h>
13 #include <linux/objtool.h>
14 #include <linux/pgtable.h>
15 #include <acpi/reboot.h>
18 #include <asm/io_apic.h>
21 #include <asm/proto.h>
22 #include <asm/reboot_fixups.h>
23 #include <asm/reboot.h>
24 #include <asm/pci_x86.h>
29 #include <linux/ctype.h>
30 #include <linux/mc146818rtc.h>
31 #include <asm/realmode.h>
32 #include <asm/x86_init.h>
36 * Power off function, if any
38 void (*pm_power_off)(void);
39 EXPORT_SYMBOL(pm_power_off);
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
46 static int reboot_emergency;
48 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
49 bool port_cf9_safe = false;
52 * Reboot options and system auto-detection code provided by
53 * Dell Inc. so their systems "just work". :-)
57 * Some machines require the "reboot=a" commandline options
59 static int __init set_acpi_reboot(const struct dmi_system_id *d)
61 if (reboot_type != BOOT_ACPI) {
62 reboot_type = BOOT_ACPI;
63 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
70 * Some machines require the "reboot=b" or "reboot=k" commandline options,
71 * this quirk makes that automatic.
73 static int __init set_bios_reboot(const struct dmi_system_id *d)
75 if (reboot_type != BOOT_BIOS) {
76 reboot_type = BOOT_BIOS;
77 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
84 * Some machines don't handle the default ACPI reboot method and
85 * require the EFI reboot method:
87 static int __init set_efi_reboot(const struct dmi_system_id *d)
89 if (reboot_type != BOOT_EFI && !efi_runtime_disabled()) {
90 reboot_type = BOOT_EFI;
91 pr_info("%s series board detected. Selecting EFI-method for reboot.\n", d->ident);
96 void __noreturn machine_real_restart(unsigned int type)
101 * Write zero to CMOS register number 0x0f, which the BIOS POST
102 * routine will recognize as telling it to do a proper reboot. (Well
103 * that's what this book in front of me says -- it may only apply to
104 * the Phoenix BIOS though, it's not clear). At the same time,
105 * disable NMIs by setting the top bit in the CMOS address register,
106 * as we're about to do peculiar things to the CPU. I'm not sure if
107 * `outb_p' is needed instead of just `outb'. Use it to be on the
108 * safe side. (Yes, CMOS_WRITE does outb_p's. - Paul G.)
110 spin_lock(&rtc_lock);
111 CMOS_WRITE(0x00, 0x8f);
112 spin_unlock(&rtc_lock);
115 * Switch to the trampoline page table.
117 load_trampoline_pgtable();
119 /* Jump to the identity-mapped low memory code */
121 asm volatile("jmpl *%0" : :
122 "rm" (real_mode_header->machine_real_restart_asm),
125 asm volatile("ljmpl *%0" : :
126 "m" (real_mode_header->machine_real_restart_asm),
131 #ifdef CONFIG_APM_MODULE
132 EXPORT_SYMBOL(machine_real_restart);
134 STACK_FRAME_NON_STANDARD(machine_real_restart);
137 * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
139 static int __init set_pci_reboot(const struct dmi_system_id *d)
141 if (reboot_type != BOOT_CF9_FORCE) {
142 reboot_type = BOOT_CF9_FORCE;
143 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
149 static int __init set_kbd_reboot(const struct dmi_system_id *d)
151 if (reboot_type != BOOT_KBD) {
152 reboot_type = BOOT_KBD;
153 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
160 * This is a single dmi_table handling all reboot quirks.
162 static const struct dmi_system_id reboot_dmi_table[] __initconst = {
165 { /* Handle reboot issue on Acer Aspire one */
166 .callback = set_kbd_reboot,
167 .ident = "Acer Aspire One A110",
169 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
170 DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
173 { /* Handle reboot issue on Acer TravelMate X514-51T */
174 .callback = set_efi_reboot,
175 .ident = "Acer TravelMate X514-51T",
177 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
178 DMI_MATCH(DMI_PRODUCT_NAME, "TravelMate X514-51T"),
183 { /* Handle problems with rebooting on Apple MacBook5 */
184 .callback = set_pci_reboot,
185 .ident = "Apple MacBook5",
187 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
188 DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
191 { /* Handle problems with rebooting on Apple MacBook6,1 */
192 .callback = set_pci_reboot,
193 .ident = "Apple MacBook6,1",
195 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
196 DMI_MATCH(DMI_PRODUCT_NAME, "MacBook6,1"),
199 { /* Handle problems with rebooting on Apple MacBookPro5 */
200 .callback = set_pci_reboot,
201 .ident = "Apple MacBookPro5",
203 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
204 DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
207 { /* Handle problems with rebooting on Apple Macmini3,1 */
208 .callback = set_pci_reboot,
209 .ident = "Apple Macmini3,1",
211 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
212 DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
215 { /* Handle problems with rebooting on the iMac9,1. */
216 .callback = set_pci_reboot,
217 .ident = "Apple iMac9,1",
219 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
220 DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
223 { /* Handle problems with rebooting on the iMac10,1. */
224 .callback = set_pci_reboot,
225 .ident = "Apple iMac10,1",
227 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
228 DMI_MATCH(DMI_PRODUCT_NAME, "iMac10,1"),
233 { /* Handle problems with rebooting on ASRock Q1900DC-ITX */
234 .callback = set_pci_reboot,
235 .ident = "ASRock Q1900DC-ITX",
237 DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
238 DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
243 { /* Handle problems with rebooting on ASUS P4S800 */
244 .callback = set_bios_reboot,
245 .ident = "ASUS P4S800",
247 DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
248 DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
251 { /* Handle problems with rebooting on ASUS EeeBook X205TA */
252 .callback = set_acpi_reboot,
253 .ident = "ASUS EeeBook X205TA",
255 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
256 DMI_MATCH(DMI_PRODUCT_NAME, "X205TA"),
259 { /* Handle problems with rebooting on ASUS EeeBook X205TAW */
260 .callback = set_acpi_reboot,
261 .ident = "ASUS EeeBook X205TAW",
263 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
264 DMI_MATCH(DMI_PRODUCT_NAME, "X205TAW"),
269 { /* Handle problems with rebooting on Certec BPC600 */
270 .callback = set_pci_reboot,
271 .ident = "Certec BPC600",
273 DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
274 DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
279 { /* Handle problems with rebooting on Dell DXP061 */
280 .callback = set_bios_reboot,
281 .ident = "Dell DXP061",
283 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
284 DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
287 { /* Handle problems with rebooting on Dell E520's */
288 .callback = set_bios_reboot,
289 .ident = "Dell E520",
291 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
292 DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
295 { /* Handle problems with rebooting on the Latitude E5410. */
296 .callback = set_pci_reboot,
297 .ident = "Dell Latitude E5410",
299 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
300 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
303 { /* Handle problems with rebooting on the Latitude E5420. */
304 .callback = set_pci_reboot,
305 .ident = "Dell Latitude E5420",
307 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
308 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
311 { /* Handle problems with rebooting on the Latitude E6320. */
312 .callback = set_pci_reboot,
313 .ident = "Dell Latitude E6320",
315 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
316 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
319 { /* Handle problems with rebooting on the Latitude E6420. */
320 .callback = set_pci_reboot,
321 .ident = "Dell Latitude E6420",
323 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
324 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
327 { /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
328 .callback = set_bios_reboot,
329 .ident = "Dell OptiPlex 330",
331 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
332 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
333 DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
336 { /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
337 .callback = set_bios_reboot,
338 .ident = "Dell OptiPlex 360",
340 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
341 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
342 DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
345 { /* Handle problems with rebooting on Dell Optiplex 745's SFF */
346 .callback = set_bios_reboot,
347 .ident = "Dell OptiPlex 745",
349 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
350 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
353 { /* Handle problems with rebooting on Dell Optiplex 745's DFF */
354 .callback = set_bios_reboot,
355 .ident = "Dell OptiPlex 745",
357 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
358 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
359 DMI_MATCH(DMI_BOARD_NAME, "0MM599"),
362 { /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
363 .callback = set_bios_reboot,
364 .ident = "Dell OptiPlex 745",
366 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
367 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
368 DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
371 { /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
372 .callback = set_bios_reboot,
373 .ident = "Dell OptiPlex 760",
375 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
376 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
377 DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
380 { /* Handle problems with rebooting on the OptiPlex 990. */
381 .callback = set_pci_reboot,
382 .ident = "Dell OptiPlex 990 BIOS A0x",
384 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
385 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
386 DMI_MATCH(DMI_BIOS_VERSION, "A0"),
389 { /* Handle problems with rebooting on Dell 300's */
390 .callback = set_bios_reboot,
391 .ident = "Dell PowerEdge 300",
393 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
394 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
397 { /* Handle problems with rebooting on Dell 1300's */
398 .callback = set_bios_reboot,
399 .ident = "Dell PowerEdge 1300",
401 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
402 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
405 { /* Handle problems with rebooting on Dell 2400's */
406 .callback = set_bios_reboot,
407 .ident = "Dell PowerEdge 2400",
409 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
410 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
413 { /* Handle problems with rebooting on the Dell PowerEdge C6100. */
414 .callback = set_pci_reboot,
415 .ident = "Dell PowerEdge C6100",
417 DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
418 DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
421 { /* Handle problems with rebooting on the Precision M6600. */
422 .callback = set_pci_reboot,
423 .ident = "Dell Precision M6600",
425 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
426 DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
429 { /* Handle problems with rebooting on Dell T5400's */
430 .callback = set_bios_reboot,
431 .ident = "Dell Precision T5400",
433 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
434 DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
437 { /* Handle problems with rebooting on Dell T7400's */
438 .callback = set_bios_reboot,
439 .ident = "Dell Precision T7400",
441 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
442 DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
445 { /* Handle problems with rebooting on Dell XPS710 */
446 .callback = set_bios_reboot,
447 .ident = "Dell XPS710",
449 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
450 DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
453 { /* Handle problems with rebooting on Dell Optiplex 7450 AIO */
454 .callback = set_acpi_reboot,
455 .ident = "Dell OptiPlex 7450 AIO",
457 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
458 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7450 AIO"),
462 /* Hewlett-Packard */
463 { /* Handle problems with rebooting on HP laptops */
464 .callback = set_bios_reboot,
465 .ident = "HP Compaq Laptop",
467 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
468 DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
472 { /* PCIe Wifi card isn't detected after reboot otherwise */
473 .callback = set_pci_reboot,
474 .ident = "Zotac ZBOX CI327 nano",
476 DMI_MATCH(DMI_SYS_VENDOR, "NA"),
477 DMI_MATCH(DMI_PRODUCT_NAME, "ZBOX-CI327NANO-GS-01"),
482 { /* Handle problems with rebooting on Sony VGN-Z540N */
483 .callback = set_bios_reboot,
484 .ident = "Sony VGN-Z540N",
486 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
487 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
494 static int __init reboot_init(void)
499 * Only do the DMI check if reboot_type hasn't been overridden
500 * on the command line
506 * The DMI quirks table takes precedence. If no quirks entry
507 * matches and the ACPI Hardware Reduced bit is set and EFI
508 * runtime services are enabled, force EFI reboot.
510 rv = dmi_check_system(reboot_dmi_table);
512 if (!rv && efi_reboot_required() && !efi_runtime_disabled())
513 reboot_type = BOOT_EFI;
517 core_initcall(reboot_init);
519 static inline void kb_wait(void)
523 for (i = 0; i < 0x10000; i++) {
524 if ((inb(0x64) & 0x02) == 0)
530 static inline void nmi_shootdown_cpus_on_restart(void);
532 #if IS_ENABLED(CONFIG_KVM_INTEL) || IS_ENABLED(CONFIG_KVM_AMD)
533 /* RCU-protected callback to disable virtualization prior to reboot. */
534 static cpu_emergency_virt_cb __rcu *cpu_emergency_virt_callback;
536 void cpu_emergency_register_virt_callback(cpu_emergency_virt_cb *callback)
538 if (WARN_ON_ONCE(rcu_access_pointer(cpu_emergency_virt_callback)))
541 rcu_assign_pointer(cpu_emergency_virt_callback, callback);
543 EXPORT_SYMBOL_GPL(cpu_emergency_register_virt_callback);
545 void cpu_emergency_unregister_virt_callback(cpu_emergency_virt_cb *callback)
547 if (WARN_ON_ONCE(rcu_access_pointer(cpu_emergency_virt_callback) != callback))
550 rcu_assign_pointer(cpu_emergency_virt_callback, NULL);
553 EXPORT_SYMBOL_GPL(cpu_emergency_unregister_virt_callback);
556 * Disable virtualization, i.e. VMX or SVM, to ensure INIT is recognized during
557 * reboot. VMX blocks INIT if the CPU is post-VMXON, and SVM blocks INIT if
558 * GIF=0, i.e. if the crash occurred between CLGI and STGI.
560 void cpu_emergency_disable_virtualization(void)
562 cpu_emergency_virt_cb *callback;
565 * IRQs must be disabled as KVM enables virtualization in hardware via
566 * function call IPIs, i.e. IRQs need to be disabled to guarantee
567 * virtualization stays disabled.
569 lockdep_assert_irqs_disabled();
572 callback = rcu_dereference(cpu_emergency_virt_callback);
578 static void emergency_reboot_disable_virtualization(void)
583 * Disable virtualization on all CPUs before rebooting to avoid hanging
584 * the system, as VMX and SVM block INIT when running in the host.
586 * We can't take any locks and we may be on an inconsistent state, so
587 * use NMIs as IPIs to tell the other CPUs to disable VMX/SVM and halt.
589 * Do the NMI shootdown even if virtualization is off on _this_ CPU, as
590 * other CPUs may have virtualization enabled.
592 if (rcu_access_pointer(cpu_emergency_virt_callback)) {
593 /* Safely force _this_ CPU out of VMX/SVM operation. */
594 cpu_emergency_disable_virtualization();
596 /* Disable VMX/SVM and halt on other CPUs. */
597 nmi_shootdown_cpus_on_restart();
601 static void emergency_reboot_disable_virtualization(void) { }
602 #endif /* CONFIG_KVM_INTEL || CONFIG_KVM_AMD */
604 void __attribute__((weak)) mach_reboot_fixups(void)
609 * To the best of our knowledge Windows compatible x86 hardware expects
610 * the following on reboot:
612 * 1) If the FADT has the ACPI reboot register flag set, try it
613 * 2) If still alive, write to the keyboard controller
614 * 3) If still alive, write to the ACPI reboot register again
615 * 4) If still alive, write to the keyboard controller again
616 * 5) If still alive, call the EFI runtime service to reboot
617 * 6) If no EFI runtime service, call the BIOS to do a reboot
619 * We default to following the same pattern. We also have
620 * two other reboot methods: 'triple fault' and 'PCI', which
621 * can be triggered via the reboot= kernel boot option or
624 * This means that this function can never return, it can misbehave
625 * by not rebooting properly and hanging.
627 static void native_machine_emergency_restart(void)
631 int orig_reboot_type = reboot_type;
634 if (reboot_emergency)
635 emergency_reboot_disable_virtualization();
637 tboot_shutdown(TB_SHUTDOWN_REBOOT);
639 /* Tell the BIOS if we want cold or warm reboot */
640 mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
641 *((unsigned short *)__va(0x472)) = mode;
644 * If an EFI capsule has been registered with the firmware then
645 * override the reboot= parameter.
647 if (efi_capsule_pending(NULL)) {
648 pr_info("EFI capsule is pending, forcing EFI reboot.\n");
649 reboot_type = BOOT_EFI;
653 /* Could also try the reset bit in the Hammer NB */
654 switch (reboot_type) {
657 reboot_type = BOOT_KBD;
661 mach_reboot_fixups(); /* For board specific fixups */
663 for (i = 0; i < 10; i++) {
666 outb(0xfe, 0x64); /* Pulse reset low */
669 if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
671 reboot_type = BOOT_ACPI;
673 reboot_type = BOOT_EFI;
678 efi_reboot(reboot_mode, NULL);
679 reboot_type = BOOT_BIOS;
683 machine_real_restart(MRR_BIOS);
685 /* We're probably dead after this, but... */
686 reboot_type = BOOT_CF9_SAFE;
690 port_cf9_safe = true;
695 u8 reboot_code = reboot_mode == REBOOT_WARM ? 0x06 : 0x0E;
696 u8 cf9 = inb(0xcf9) & ~reboot_code;
697 outb(cf9|2, 0xcf9); /* Request hard reset */
699 /* Actually do the reset */
700 outb(cf9|reboot_code, 0xcf9);
703 reboot_type = BOOT_TRIPLE;
708 __asm__ __volatile__("int3");
710 /* We're probably dead after this, but... */
711 reboot_type = BOOT_KBD;
717 void native_machine_shutdown(void)
719 /* Stop the cpus and apics */
720 #ifdef CONFIG_X86_IO_APIC
722 * Disabling IO APIC before local APIC is a workaround for
723 * erratum AVR31 in "Intel Atom Processor C2000 Product Family
724 * Specification Update". In this situation, interrupts that target
725 * a Logical Processor whose Local APIC is either in the process of
726 * being hardware disabled or software disabled are neither delivered
727 * nor discarded. When this erratum occurs, the processor may hang.
729 * Even without the erratum, it still makes sense to quiet IO APIC
730 * before disabling Local APIC.
737 * Stop all of the others. Also disable the local irq to
738 * not receive the per-cpu timer interrupt which may trigger
739 * scheduler's load balance.
746 restore_boot_irq_mode();
748 #ifdef CONFIG_HPET_TIMER
753 x86_platform.iommu_shutdown();
757 static void __machine_emergency_restart(int emergency)
759 reboot_emergency = emergency;
760 machine_ops.emergency_restart();
763 static void native_machine_restart(char *__unused)
765 pr_notice("machine restart\n");
769 __machine_emergency_restart(0);
772 static void native_machine_halt(void)
774 /* Stop other cpus and apics */
777 tboot_shutdown(TB_SHUTDOWN_HALT);
782 static void native_machine_power_off(void)
784 if (kernel_can_power_off()) {
787 do_kernel_power_off();
789 /* A fallback in case there is no PM info available */
790 tboot_shutdown(TB_SHUTDOWN_HALT);
793 struct machine_ops machine_ops __ro_after_init = {
794 .power_off = native_machine_power_off,
795 .shutdown = native_machine_shutdown,
796 .emergency_restart = native_machine_emergency_restart,
797 .restart = native_machine_restart,
798 .halt = native_machine_halt,
799 #ifdef CONFIG_KEXEC_CORE
800 .crash_shutdown = native_machine_crash_shutdown,
804 void machine_power_off(void)
806 machine_ops.power_off();
809 void machine_shutdown(void)
811 machine_ops.shutdown();
814 void machine_emergency_restart(void)
816 __machine_emergency_restart(1);
819 void machine_restart(char *cmd)
821 machine_ops.restart(cmd);
824 void machine_halt(void)
829 #ifdef CONFIG_KEXEC_CORE
830 void machine_crash_shutdown(struct pt_regs *regs)
832 machine_ops.crash_shutdown(regs);
836 /* This is the CPU performing the emergency shutdown work. */
837 int crashing_cpu = -1;
839 #if defined(CONFIG_SMP)
841 static nmi_shootdown_cb shootdown_callback;
843 static atomic_t waiting_for_crash_ipi;
844 static int crash_ipi_issued;
846 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
850 cpu = raw_smp_processor_id();
853 * Don't do anything if this handler is invoked on crashing cpu.
854 * Otherwise, system will completely hang. Crashing cpu can get
855 * an NMI if system was initially booted with nmi_watchdog parameter.
857 if (cpu == crashing_cpu)
861 if (shootdown_callback)
862 shootdown_callback(cpu, regs);
865 * Prepare the CPU for reboot _after_ invoking the callback so that the
866 * callback can safely use virtualization instructions, e.g. VMCLEAR.
868 cpu_emergency_disable_virtualization();
870 atomic_dec(&waiting_for_crash_ipi);
871 /* Assume hlt works */
880 * nmi_shootdown_cpus - Stop other CPUs via NMI
881 * @callback: Optional callback to be invoked from the NMI handler
883 * The NMI handler on the remote CPUs invokes @callback, if not
884 * NULL, first and then disables virtualization to ensure that
885 * INIT is recognized during reboot.
887 * nmi_shootdown_cpus() can only be invoked once. After the first
888 * invocation all other CPUs are stuck in crash_nmi_callback() and
889 * cannot respond to a second NMI.
891 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
898 * Avoid certain doom if a shootdown already occurred; re-registering
899 * the NMI handler will cause list corruption, modifying the callback
900 * will do who knows what, etc...
902 if (WARN_ON_ONCE(crash_ipi_issued))
905 /* Make a note of crashing cpu. Will be used in NMI callback. */
906 crashing_cpu = safe_smp_processor_id();
908 shootdown_callback = callback;
910 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
911 /* Would it be better to replace the trap vector here? */
912 if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
913 NMI_FLAG_FIRST, "crash"))
914 return; /* Return what? */
916 * Ensure the new callback function is set before sending
921 apic_send_IPI_allbutself(NMI_VECTOR);
923 /* Kick CPUs looping in NMI context. */
924 WRITE_ONCE(crash_ipi_issued, 1);
926 msecs = 1000; /* Wait at most a second for the other cpus to stop */
927 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
933 * Leave the nmi callback set, shootdown is a one-time thing. Clearing
934 * the callback could result in a NULL pointer dereference if a CPU
935 * (finally) responds after the timeout expires.
939 static inline void nmi_shootdown_cpus_on_restart(void)
941 if (!crash_ipi_issued)
942 nmi_shootdown_cpus(NULL);
946 * Check if the crash dumping IPI got issued and if so, call its callback
947 * directly. This function is used when we have already been in NMI handler.
950 void run_crash_ipi_callback(struct pt_regs *regs)
952 if (crash_ipi_issued)
953 crash_nmi_callback(0, regs);
956 /* Override the weak function in kernel/panic.c */
957 void __noreturn nmi_panic_self_stop(struct pt_regs *regs)
960 /* If no CPU is preparing crash dump, we simply loop here. */
961 run_crash_ipi_callback(regs);
966 #else /* !CONFIG_SMP */
967 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
969 /* No other CPUs to shoot down */
972 static inline void nmi_shootdown_cpus_on_restart(void) { }
974 void run_crash_ipi_callback(struct pt_regs *regs)