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>
25 #include <asm/virtext.h>
30 #include <linux/ctype.h>
31 #include <linux/mc146818rtc.h>
32 #include <asm/realmode.h>
33 #include <asm/x86_init.h>
37 * Power off function, if any
39 void (*pm_power_off)(void);
40 EXPORT_SYMBOL(pm_power_off);
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
47 static int reboot_emergency;
49 /* This is set by the PCI code if either type 1 or type 2 PCI is detected */
50 bool port_cf9_safe = false;
53 * Reboot options and system auto-detection code provided by
54 * Dell Inc. so their systems "just work". :-)
58 * Some machines require the "reboot=a" commandline options
60 static int __init set_acpi_reboot(const struct dmi_system_id *d)
62 if (reboot_type != BOOT_ACPI) {
63 reboot_type = BOOT_ACPI;
64 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
71 * Some machines require the "reboot=b" or "reboot=k" commandline options,
72 * this quirk makes that automatic.
74 static int __init set_bios_reboot(const struct dmi_system_id *d)
76 if (reboot_type != BOOT_BIOS) {
77 reboot_type = BOOT_BIOS;
78 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
85 * Some machines don't handle the default ACPI reboot method and
86 * require the EFI reboot method:
88 static int __init set_efi_reboot(const struct dmi_system_id *d)
90 if (reboot_type != BOOT_EFI && !efi_runtime_disabled()) {
91 reboot_type = BOOT_EFI;
92 pr_info("%s series board detected. Selecting EFI-method for reboot.\n", d->ident);
97 void __noreturn machine_real_restart(unsigned int type)
102 * Write zero to CMOS register number 0x0f, which the BIOS POST
103 * routine will recognize as telling it to do a proper reboot. (Well
104 * that's what this book in front of me says -- it may only apply to
105 * the Phoenix BIOS though, it's not clear). At the same time,
106 * disable NMIs by setting the top bit in the CMOS address register,
107 * as we're about to do peculiar things to the CPU. I'm not sure if
108 * `outb_p' is needed instead of just `outb'. Use it to be on the
109 * safe side. (Yes, CMOS_WRITE does outb_p's. - Paul G.)
111 spin_lock(&rtc_lock);
112 CMOS_WRITE(0x00, 0x8f);
113 spin_unlock(&rtc_lock);
116 * Switch back to the initial page table.
119 load_cr3(initial_page_table);
121 write_cr3(real_mode_header->trampoline_pgd);
123 /* Exiting long mode will fail if CR4.PCIDE is set. */
124 if (boot_cpu_has(X86_FEATURE_PCID))
125 cr4_clear_bits(X86_CR4_PCIDE);
128 /* Jump to the identity-mapped low memory code */
130 asm volatile("jmpl *%0" : :
131 "rm" (real_mode_header->machine_real_restart_asm),
134 asm volatile("ljmpl *%0" : :
135 "m" (real_mode_header->machine_real_restart_asm),
140 #ifdef CONFIG_APM_MODULE
141 EXPORT_SYMBOL(machine_real_restart);
143 STACK_FRAME_NON_STANDARD(machine_real_restart);
146 * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot
148 static int __init set_pci_reboot(const struct dmi_system_id *d)
150 if (reboot_type != BOOT_CF9_FORCE) {
151 reboot_type = BOOT_CF9_FORCE;
152 pr_info("%s series board detected. Selecting %s-method for reboots.\n",
158 static int __init set_kbd_reboot(const struct dmi_system_id *d)
160 if (reboot_type != BOOT_KBD) {
161 reboot_type = BOOT_KBD;
162 pr_info("%s series board detected. Selecting %s-method for reboot.\n",
169 * This is a single dmi_table handling all reboot quirks.
171 static const struct dmi_system_id reboot_dmi_table[] __initconst = {
174 { /* Handle reboot issue on Acer Aspire one */
175 .callback = set_kbd_reboot,
176 .ident = "Acer Aspire One A110",
178 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
179 DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
182 { /* Handle reboot issue on Acer TravelMate X514-51T */
183 .callback = set_efi_reboot,
184 .ident = "Acer TravelMate X514-51T",
186 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
187 DMI_MATCH(DMI_PRODUCT_NAME, "TravelMate X514-51T"),
192 { /* Handle problems with rebooting on Apple MacBook5 */
193 .callback = set_pci_reboot,
194 .ident = "Apple MacBook5",
196 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
197 DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"),
200 { /* Handle problems with rebooting on Apple MacBook6,1 */
201 .callback = set_pci_reboot,
202 .ident = "Apple MacBook6,1",
204 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
205 DMI_MATCH(DMI_PRODUCT_NAME, "MacBook6,1"),
208 { /* Handle problems with rebooting on Apple MacBookPro5 */
209 .callback = set_pci_reboot,
210 .ident = "Apple MacBookPro5",
212 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
213 DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"),
216 { /* Handle problems with rebooting on Apple Macmini3,1 */
217 .callback = set_pci_reboot,
218 .ident = "Apple Macmini3,1",
220 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
221 DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
224 { /* Handle problems with rebooting on the iMac9,1. */
225 .callback = set_pci_reboot,
226 .ident = "Apple iMac9,1",
228 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
229 DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
232 { /* Handle problems with rebooting on the iMac10,1. */
233 .callback = set_pci_reboot,
234 .ident = "Apple iMac10,1",
236 DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
237 DMI_MATCH(DMI_PRODUCT_NAME, "iMac10,1"),
242 { /* Handle problems with rebooting on ASRock Q1900DC-ITX */
243 .callback = set_pci_reboot,
244 .ident = "ASRock Q1900DC-ITX",
246 DMI_MATCH(DMI_BOARD_VENDOR, "ASRock"),
247 DMI_MATCH(DMI_BOARD_NAME, "Q1900DC-ITX"),
252 { /* Handle problems with rebooting on ASUS P4S800 */
253 .callback = set_bios_reboot,
254 .ident = "ASUS P4S800",
256 DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
257 DMI_MATCH(DMI_BOARD_NAME, "P4S800"),
260 { /* Handle problems with rebooting on ASUS EeeBook X205TA */
261 .callback = set_acpi_reboot,
262 .ident = "ASUS EeeBook X205TA",
264 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
265 DMI_MATCH(DMI_PRODUCT_NAME, "X205TA"),
268 { /* Handle problems with rebooting on ASUS EeeBook X205TAW */
269 .callback = set_acpi_reboot,
270 .ident = "ASUS EeeBook X205TAW",
272 DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
273 DMI_MATCH(DMI_PRODUCT_NAME, "X205TAW"),
278 { /* Handle problems with rebooting on Certec BPC600 */
279 .callback = set_pci_reboot,
280 .ident = "Certec BPC600",
282 DMI_MATCH(DMI_SYS_VENDOR, "Certec"),
283 DMI_MATCH(DMI_PRODUCT_NAME, "BPC600"),
288 { /* Handle problems with rebooting on Dell DXP061 */
289 .callback = set_bios_reboot,
290 .ident = "Dell DXP061",
292 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
293 DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"),
296 { /* Handle problems with rebooting on Dell E520's */
297 .callback = set_bios_reboot,
298 .ident = "Dell E520",
300 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
301 DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"),
304 { /* Handle problems with rebooting on the Latitude E5410. */
305 .callback = set_pci_reboot,
306 .ident = "Dell Latitude E5410",
308 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
309 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5410"),
312 { /* Handle problems with rebooting on the Latitude E5420. */
313 .callback = set_pci_reboot,
314 .ident = "Dell Latitude E5420",
316 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
317 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"),
320 { /* Handle problems with rebooting on the Latitude E6320. */
321 .callback = set_pci_reboot,
322 .ident = "Dell Latitude E6320",
324 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
325 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"),
328 { /* Handle problems with rebooting on the Latitude E6420. */
329 .callback = set_pci_reboot,
330 .ident = "Dell Latitude E6420",
332 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
333 DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"),
336 { /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */
337 .callback = set_bios_reboot,
338 .ident = "Dell OptiPlex 330",
340 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
341 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"),
342 DMI_MATCH(DMI_BOARD_NAME, "0KP561"),
345 { /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */
346 .callback = set_bios_reboot,
347 .ident = "Dell OptiPlex 360",
349 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
350 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"),
351 DMI_MATCH(DMI_BOARD_NAME, "0T656F"),
354 { /* Handle problems with rebooting on Dell Optiplex 745's SFF */
355 .callback = set_bios_reboot,
356 .ident = "Dell OptiPlex 745",
358 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
359 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
362 { /* Handle problems with rebooting on Dell Optiplex 745's DFF */
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, "0MM599"),
371 { /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */
372 .callback = set_bios_reboot,
373 .ident = "Dell OptiPlex 745",
375 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
376 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"),
377 DMI_MATCH(DMI_BOARD_NAME, "0KW626"),
380 { /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */
381 .callback = set_bios_reboot,
382 .ident = "Dell OptiPlex 760",
384 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
385 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"),
386 DMI_MATCH(DMI_BOARD_NAME, "0G919G"),
389 { /* Handle problems with rebooting on the OptiPlex 990. */
390 .callback = set_pci_reboot,
391 .ident = "Dell OptiPlex 990",
393 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
394 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"),
397 { /* Handle problems with rebooting on Dell 300's */
398 .callback = set_bios_reboot,
399 .ident = "Dell PowerEdge 300",
401 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
402 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"),
405 { /* Handle problems with rebooting on Dell 1300's */
406 .callback = set_bios_reboot,
407 .ident = "Dell PowerEdge 1300",
409 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
410 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"),
413 { /* Handle problems with rebooting on Dell 2400's */
414 .callback = set_bios_reboot,
415 .ident = "Dell PowerEdge 2400",
417 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
418 DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"),
421 { /* Handle problems with rebooting on the Dell PowerEdge C6100. */
422 .callback = set_pci_reboot,
423 .ident = "Dell PowerEdge C6100",
425 DMI_MATCH(DMI_SYS_VENDOR, "Dell"),
426 DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
429 { /* Handle problems with rebooting on the Precision M6600. */
430 .callback = set_pci_reboot,
431 .ident = "Dell Precision M6600",
433 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
434 DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"),
437 { /* Handle problems with rebooting on Dell T5400's */
438 .callback = set_bios_reboot,
439 .ident = "Dell Precision T5400",
441 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
442 DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"),
445 { /* Handle problems with rebooting on Dell T7400's */
446 .callback = set_bios_reboot,
447 .ident = "Dell Precision T7400",
449 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
450 DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"),
453 { /* Handle problems with rebooting on Dell XPS710 */
454 .callback = set_bios_reboot,
455 .ident = "Dell XPS710",
457 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
458 DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"),
461 { /* Handle problems with rebooting on Dell Optiplex 7450 AIO */
462 .callback = set_acpi_reboot,
463 .ident = "Dell OptiPlex 7450 AIO",
465 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
466 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7450 AIO"),
470 /* Hewlett-Packard */
471 { /* Handle problems with rebooting on HP laptops */
472 .callback = set_bios_reboot,
473 .ident = "HP Compaq Laptop",
475 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
476 DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"),
480 { /* PCIe Wifi card isn't detected after reboot otherwise */
481 .callback = set_pci_reboot,
482 .ident = "Zotac ZBOX CI327 nano",
484 DMI_MATCH(DMI_SYS_VENDOR, "NA"),
485 DMI_MATCH(DMI_PRODUCT_NAME, "ZBOX-CI327NANO-GS-01"),
490 { /* Handle problems with rebooting on Sony VGN-Z540N */
491 .callback = set_bios_reboot,
492 .ident = "Sony VGN-Z540N",
494 DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
495 DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"),
502 static int __init reboot_init(void)
507 * Only do the DMI check if reboot_type hasn't been overridden
508 * on the command line
514 * The DMI quirks table takes precedence. If no quirks entry
515 * matches and the ACPI Hardware Reduced bit is set and EFI
516 * runtime services are enabled, force EFI reboot.
518 rv = dmi_check_system(reboot_dmi_table);
520 if (!rv && efi_reboot_required() && !efi_runtime_disabled())
521 reboot_type = BOOT_EFI;
525 core_initcall(reboot_init);
527 static inline void kb_wait(void)
531 for (i = 0; i < 0x10000; i++) {
532 if ((inb(0x64) & 0x02) == 0)
538 static void vmxoff_nmi(int cpu, struct pt_regs *regs)
540 cpu_emergency_vmxoff();
543 /* Use NMIs as IPIs to tell all CPUs to disable virtualization */
544 static void emergency_vmx_disable_all(void)
546 /* Just make sure we won't change CPUs while doing this */
550 * Disable VMX on all CPUs before rebooting, otherwise we risk hanging
551 * the machine, because the CPU blocks INIT when it's in VMX root.
553 * We can't take any locks and we may be on an inconsistent state, so
554 * use NMIs as IPIs to tell the other CPUs to exit VMX root and halt.
556 * Do the NMI shootdown even if VMX if off on _this_ CPU, as that
557 * doesn't prevent a different CPU from being in VMX root operation.
560 /* Safely force _this_ CPU out of VMX root operation. */
561 __cpu_emergency_vmxoff();
563 /* Halt and exit VMX root operation on the other CPUs. */
564 nmi_shootdown_cpus(vmxoff_nmi);
569 void __attribute__((weak)) mach_reboot_fixups(void)
574 * To the best of our knowledge Windows compatible x86 hardware expects
575 * the following on reboot:
577 * 1) If the FADT has the ACPI reboot register flag set, try it
578 * 2) If still alive, write to the keyboard controller
579 * 3) If still alive, write to the ACPI reboot register again
580 * 4) If still alive, write to the keyboard controller again
581 * 5) If still alive, call the EFI runtime service to reboot
582 * 6) If no EFI runtime service, call the BIOS to do a reboot
584 * We default to following the same pattern. We also have
585 * two other reboot methods: 'triple fault' and 'PCI', which
586 * can be triggered via the reboot= kernel boot option or
589 * This means that this function can never return, it can misbehave
590 * by not rebooting properly and hanging.
592 static void native_machine_emergency_restart(void)
596 int orig_reboot_type = reboot_type;
599 if (reboot_emergency)
600 emergency_vmx_disable_all();
602 tboot_shutdown(TB_SHUTDOWN_REBOOT);
604 /* Tell the BIOS if we want cold or warm reboot */
605 mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
606 *((unsigned short *)__va(0x472)) = mode;
609 * If an EFI capsule has been registered with the firmware then
610 * override the reboot= parameter.
612 if (efi_capsule_pending(NULL)) {
613 pr_info("EFI capsule is pending, forcing EFI reboot.\n");
614 reboot_type = BOOT_EFI;
618 /* Could also try the reset bit in the Hammer NB */
619 switch (reboot_type) {
622 reboot_type = BOOT_KBD;
626 mach_reboot_fixups(); /* For board specific fixups */
628 for (i = 0; i < 10; i++) {
631 outb(0xfe, 0x64); /* Pulse reset low */
634 if (attempt == 0 && orig_reboot_type == BOOT_ACPI) {
636 reboot_type = BOOT_ACPI;
638 reboot_type = BOOT_EFI;
643 efi_reboot(reboot_mode, NULL);
644 reboot_type = BOOT_BIOS;
648 machine_real_restart(MRR_BIOS);
650 /* We're probably dead after this, but... */
651 reboot_type = BOOT_CF9_SAFE;
655 port_cf9_safe = true;
660 u8 reboot_code = reboot_mode == REBOOT_WARM ? 0x06 : 0x0E;
661 u8 cf9 = inb(0xcf9) & ~reboot_code;
662 outb(cf9|2, 0xcf9); /* Request hard reset */
664 /* Actually do the reset */
665 outb(cf9|reboot_code, 0xcf9);
668 reboot_type = BOOT_TRIPLE;
672 idt_invalidate(NULL);
673 __asm__ __volatile__("int3");
675 /* We're probably dead after this, but... */
676 reboot_type = BOOT_KBD;
682 void native_machine_shutdown(void)
684 /* Stop the cpus and apics */
685 #ifdef CONFIG_X86_IO_APIC
687 * Disabling IO APIC before local APIC is a workaround for
688 * erratum AVR31 in "Intel Atom Processor C2000 Product Family
689 * Specification Update". In this situation, interrupts that target
690 * a Logical Processor whose Local APIC is either in the process of
691 * being hardware disabled or software disabled are neither delivered
692 * nor discarded. When this erratum occurs, the processor may hang.
694 * Even without the erratum, it still makes sense to quiet IO APIC
695 * before disabling Local APIC.
702 * Stop all of the others. Also disable the local irq to
703 * not receive the per-cpu timer interrupt which may trigger
704 * scheduler's load balance.
711 restore_boot_irq_mode();
713 #ifdef CONFIG_HPET_TIMER
718 x86_platform.iommu_shutdown();
722 static void __machine_emergency_restart(int emergency)
724 reboot_emergency = emergency;
725 machine_ops.emergency_restart();
728 static void native_machine_restart(char *__unused)
730 pr_notice("machine restart\n");
734 __machine_emergency_restart(0);
737 static void native_machine_halt(void)
739 /* Stop other cpus and apics */
742 tboot_shutdown(TB_SHUTDOWN_HALT);
747 static void native_machine_power_off(void)
754 /* A fallback in case there is no PM info available */
755 tboot_shutdown(TB_SHUTDOWN_HALT);
758 struct machine_ops machine_ops __ro_after_init = {
759 .power_off = native_machine_power_off,
760 .shutdown = native_machine_shutdown,
761 .emergency_restart = native_machine_emergency_restart,
762 .restart = native_machine_restart,
763 .halt = native_machine_halt,
764 #ifdef CONFIG_KEXEC_CORE
765 .crash_shutdown = native_machine_crash_shutdown,
769 void machine_power_off(void)
771 machine_ops.power_off();
774 void machine_shutdown(void)
776 machine_ops.shutdown();
779 void machine_emergency_restart(void)
781 __machine_emergency_restart(1);
784 void machine_restart(char *cmd)
786 machine_ops.restart(cmd);
789 void machine_halt(void)
794 #ifdef CONFIG_KEXEC_CORE
795 void machine_crash_shutdown(struct pt_regs *regs)
797 machine_ops.crash_shutdown(regs);
802 /* This is the CPU performing the emergency shutdown work. */
803 int crashing_cpu = -1;
805 #if defined(CONFIG_SMP)
807 static nmi_shootdown_cb shootdown_callback;
809 static atomic_t waiting_for_crash_ipi;
810 static int crash_ipi_issued;
812 static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
816 cpu = raw_smp_processor_id();
819 * Don't do anything if this handler is invoked on crashing cpu.
820 * Otherwise, system will completely hang. Crashing cpu can get
821 * an NMI if system was initially booted with nmi_watchdog parameter.
823 if (cpu == crashing_cpu)
827 shootdown_callback(cpu, regs);
829 atomic_dec(&waiting_for_crash_ipi);
830 /* Assume hlt works */
839 * Halt all other CPUs, calling the specified function on each of them
841 * This function can be used to halt all other CPUs on crash
842 * or emergency reboot time. The function passed as parameter
843 * will be called inside a NMI handler on all CPUs.
845 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
850 /* Make a note of crashing cpu. Will be used in NMI callback. */
851 crashing_cpu = safe_smp_processor_id();
853 shootdown_callback = callback;
855 atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
856 /* Would it be better to replace the trap vector here? */
857 if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback,
858 NMI_FLAG_FIRST, "crash"))
859 return; /* Return what? */
861 * Ensure the new callback function is set before sending
866 apic_send_IPI_allbutself(NMI_VECTOR);
868 /* Kick CPUs looping in NMI context. */
869 WRITE_ONCE(crash_ipi_issued, 1);
871 msecs = 1000; /* Wait at most a second for the other cpus to stop */
872 while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
877 /* Leave the nmi callback set */
881 * Check if the crash dumping IPI got issued and if so, call its callback
882 * directly. This function is used when we have already been in NMI handler.
885 void run_crash_ipi_callback(struct pt_regs *regs)
887 if (crash_ipi_issued)
888 crash_nmi_callback(0, regs);
891 /* Override the weak function in kernel/panic.c */
892 void nmi_panic_self_stop(struct pt_regs *regs)
895 /* If no CPU is preparing crash dump, we simply loop here. */
896 run_crash_ipi_callback(regs);
901 #else /* !CONFIG_SMP */
902 void nmi_shootdown_cpus(nmi_shootdown_cb callback)
904 /* No other CPUs to shoot down */
907 void run_crash_ipi_callback(struct pt_regs *regs)