diff options
Diffstat (limited to 'arch/x86/kernel/reboot.c')
| -rw-r--r-- | arch/x86/kernel/reboot.c | 837 |
1 files changed, 837 insertions, 0 deletions
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c new file mode 100644 index 00000000..3876c04f --- /dev/null +++ b/arch/x86/kernel/reboot.c @@ -0,0 +1,837 @@ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/reboot.h> +#include <linux/init.h> +#include <linux/pm.h> +#include <linux/efi.h> +#include <linux/dmi.h> +#include <linux/sched.h> +#include <linux/tboot.h> +#include <linux/delay.h> +#include <acpi/reboot.h> +#include <asm/io.h> +#include <asm/apic.h> +#include <asm/desc.h> +#include <asm/hpet.h> +#include <asm/pgtable.h> +#include <asm/proto.h> +#include <asm/reboot_fixups.h> +#include <asm/reboot.h> +#include <asm/pci_x86.h> +#include <asm/virtext.h> +#include <asm/cpu.h> +#include <asm/nmi.h> +#include <asm/smp.h> + +#include <linux/ctype.h> +#include <linux/mc146818rtc.h> +#include <asm/realmode.h> +#include <asm/x86_init.h> + +/* + * Power off function, if any + */ +void (*pm_power_off)(void); +EXPORT_SYMBOL(pm_power_off); + +static const struct desc_ptr no_idt = {}; +static enum reboot_mode reboot_mode; +enum reboot_type reboot_type = BOOT_ACPI; +int reboot_force; + +/* + * This variable is used privately to keep track of whether or not + * reboot_type is still set to its default value (i.e., reboot= hasn't + * been set on the command line). This is needed so that we can + * suppress DMI scanning for reboot quirks. Without it, it's + * impossible to override a faulty reboot quirk without recompiling. + */ +static int reboot_default = 1; + +#ifdef CONFIG_SMP +static int reboot_cpu = -1; +#endif + +/* + * This is set if we need to go through the 'emergency' path. + * When machine_emergency_restart() is called, we may be on + * an inconsistent state and won't be able to do a clean cleanup + */ +static int reboot_emergency; + +/* This is set by the PCI code if either type 1 or type 2 PCI is detected */ +bool port_cf9_safe = false; + +/* + * reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci] + * warm Don't set the cold reboot flag + * cold Set the cold reboot flag + * bios Reboot by jumping through the BIOS + * smp Reboot by executing reset on BSP or other CPU + * triple Force a triple fault (init) + * kbd Use the keyboard controller. cold reset (default) + * acpi Use the RESET_REG in the FADT + * efi Use efi reset_system runtime service + * pci Use the so-called "PCI reset register", CF9 + * force Avoid anything that could hang. + */ +static int __init reboot_setup(char *str) +{ + for (;;) { + /* + * Having anything passed on the command line via + * reboot= will cause us to disable DMI checking + * below. + */ + reboot_default = 0; + + switch (*str) { + case 'w': + reboot_mode = REBOOT_WARM; + break; + + case 'c': + reboot_mode = REBOOT_COLD; + break; + +#ifdef CONFIG_SMP + case 's': + if (isdigit(*(str+1))) { + reboot_cpu = (int) (*(str+1) - '0'); + if (isdigit(*(str+2))) + reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0'); + } + /* + * We will leave sorting out the final value + * when we are ready to reboot, since we might not + * have detected BSP APIC ID or smp_num_cpu + */ + break; +#endif /* CONFIG_SMP */ + + case 'b': + case 'a': + case 'k': + case 't': + case 'e': + case 'p': + reboot_type = *str; + break; + + case 'f': + reboot_force = 1; + break; + } + + str = strchr(str, ','); + if (str) + str++; + else + break; + } + return 1; +} + +__setup("reboot=", reboot_setup); + + +/* + * Reboot options and system auto-detection code provided by + * Dell Inc. so their systems "just work". :-) + */ + +/* + * Some machines require the "reboot=b" or "reboot=k" commandline options, + * this quirk makes that automatic. + */ +static int __init set_bios_reboot(const struct dmi_system_id *d) +{ + if (reboot_type != BOOT_BIOS) { + reboot_type = BOOT_BIOS; + pr_info("%s series board detected. Selecting %s-method for reboots.\n", + "BIOS", d->ident); + } + return 0; +} + +void __noreturn machine_real_restart(unsigned int type) +{ + local_irq_disable(); + + /* + * Write zero to CMOS register number 0x0f, which the BIOS POST + * routine will recognize as telling it to do a proper reboot. (Well + * that's what this book in front of me says -- it may only apply to + * the Phoenix BIOS though, it's not clear). At the same time, + * disable NMIs by setting the top bit in the CMOS address register, + * as we're about to do peculiar things to the CPU. I'm not sure if + * `outb_p' is needed instead of just `outb'. Use it to be on the + * safe side. (Yes, CMOS_WRITE does outb_p's. - Paul G.) + */ + spin_lock(&rtc_lock); + CMOS_WRITE(0x00, 0x8f); + spin_unlock(&rtc_lock); + + /* + * Switch back to the initial page table. + */ +#ifdef CONFIG_X86_32 + load_cr3(initial_page_table); +#else + write_cr3(real_mode_header->trampoline_pgd); +#endif + + /* Jump to the identity-mapped low memory code */ +#ifdef CONFIG_X86_32 + asm volatile("jmpl *%0" : : + "rm" (real_mode_header->machine_real_restart_asm), + "a" (type)); +#else + asm volatile("ljmpl *%0" : : + "m" (real_mode_header->machine_real_restart_asm), + "D" (type)); +#endif + unreachable(); +} +#ifdef CONFIG_APM_MODULE +EXPORT_SYMBOL(machine_real_restart); +#endif + +/* + * Some Apple MacBook and MacBookPro's needs reboot=p to be able to reboot + */ +static int __init set_pci_reboot(const struct dmi_system_id *d) +{ + if (reboot_type != BOOT_CF9) { + reboot_type = BOOT_CF9; + pr_info("%s series board detected. Selecting %s-method for reboots.\n", + "PCI", d->ident); + } + return 0; +} + +static int __init set_kbd_reboot(const struct dmi_system_id *d) +{ + if (reboot_type != BOOT_KBD) { + reboot_type = BOOT_KBD; + pr_info("%s series board detected. Selecting %s-method for reboot.\n", + "KBD", d->ident); + } + return 0; +} + +/* + * This is a single dmi_table handling all reboot quirks. + */ +static struct dmi_system_id __initdata reboot_dmi_table[] = { + { /* Handle problems with rebooting on Dell E520's */ + .callback = set_bios_reboot, + .ident = "Dell E520", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "Dell DM061"), + }, + }, + { /* Handle problems with rebooting on Dell 1300's */ + .callback = set_bios_reboot, + .ident = "Dell PowerEdge 1300", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), + DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 1300/"), + }, + }, + { /* Handle problems with rebooting on Dell 300's */ + .callback = set_bios_reboot, + .ident = "Dell PowerEdge 300", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), + DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 300/"), + }, + }, + { /* Handle problems with rebooting on Dell Optiplex 745's SFF */ + .callback = set_bios_reboot, + .ident = "Dell OptiPlex 745", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), + }, + }, + { /* Handle problems with rebooting on Dell Optiplex 745's DFF */ + .callback = set_bios_reboot, + .ident = "Dell OptiPlex 745", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), + DMI_MATCH(DMI_BOARD_NAME, "0MM599"), + }, + }, + { /* Handle problems with rebooting on Dell Optiplex 745 with 0KW626 */ + .callback = set_bios_reboot, + .ident = "Dell OptiPlex 745", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 745"), + DMI_MATCH(DMI_BOARD_NAME, "0KW626"), + }, + }, + { /* Handle problems with rebooting on Dell Optiplex 330 with 0KP561 */ + .callback = set_bios_reboot, + .ident = "Dell OptiPlex 330", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 330"), + DMI_MATCH(DMI_BOARD_NAME, "0KP561"), + }, + }, + { /* Handle problems with rebooting on Dell Optiplex 360 with 0T656F */ + .callback = set_bios_reboot, + .ident = "Dell OptiPlex 360", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 360"), + DMI_MATCH(DMI_BOARD_NAME, "0T656F"), + }, + }, + { /* Handle problems with rebooting on Dell OptiPlex 760 with 0G919G */ + .callback = set_bios_reboot, + .ident = "Dell OptiPlex 760", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 760"), + DMI_MATCH(DMI_BOARD_NAME, "0G919G"), + }, + }, + { /* Handle problems with rebooting on Dell 2400's */ + .callback = set_bios_reboot, + .ident = "Dell PowerEdge 2400", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"), + DMI_MATCH(DMI_PRODUCT_NAME, "PowerEdge 2400"), + }, + }, + { /* Handle problems with rebooting on Dell T5400's */ + .callback = set_bios_reboot, + .ident = "Dell Precision T5400", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T5400"), + }, + }, + { /* Handle problems with rebooting on Dell T7400's */ + .callback = set_bios_reboot, + .ident = "Dell Precision T7400", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "Precision WorkStation T7400"), + }, + }, + { /* Handle problems with rebooting on HP laptops */ + .callback = set_bios_reboot, + .ident = "HP Compaq Laptop", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"), + DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq"), + }, + }, + { /* Handle problems with rebooting on Dell XPS710 */ + .callback = set_bios_reboot, + .ident = "Dell XPS710", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "Dell XPS710"), + }, + }, + { /* Handle problems with rebooting on Dell DXP061 */ + .callback = set_bios_reboot, + .ident = "Dell DXP061", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "Dell DXP061"), + }, + }, + { /* Handle problems with rebooting on Sony VGN-Z540N */ + .callback = set_bios_reboot, + .ident = "Sony VGN-Z540N", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"), + DMI_MATCH(DMI_PRODUCT_NAME, "VGN-Z540N"), + }, + }, + { /* Handle problems with rebooting on ASUS P4S800 */ + .callback = set_bios_reboot, + .ident = "ASUS P4S800", + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."), + DMI_MATCH(DMI_BOARD_NAME, "P4S800"), + }, + }, + + { /* Handle reboot issue on Acer Aspire one */ + .callback = set_kbd_reboot, + .ident = "Acer Aspire One A110", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Acer"), + DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"), + }, + }, + { /* Handle problems with rebooting on Apple MacBook5 */ + .callback = set_pci_reboot, + .ident = "Apple MacBook5", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBook5"), + }, + }, + { /* Handle problems with rebooting on Apple MacBookPro5 */ + .callback = set_pci_reboot, + .ident = "Apple MacBookPro5", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro5"), + }, + }, + { /* Handle problems with rebooting on Apple Macmini3,1 */ + .callback = set_pci_reboot, + .ident = "Apple Macmini3,1", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"), + }, + }, + { /* Handle problems with rebooting on the iMac9,1. */ + .callback = set_pci_reboot, + .ident = "Apple iMac9,1", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"), + }, + }, + { /* Handle problems with rebooting on the Latitude E6320. */ + .callback = set_pci_reboot, + .ident = "Dell Latitude E6320", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6320"), + }, + }, + { /* Handle problems with rebooting on the Latitude E5420. */ + .callback = set_pci_reboot, + .ident = "Dell Latitude E5420", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E5420"), + }, + }, + { /* Handle problems with rebooting on the Latitude E6420. */ + .callback = set_pci_reboot, + .ident = "Dell Latitude E6420", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6420"), + }, + }, + { /* Handle problems with rebooting on the OptiPlex 990. */ + .callback = set_pci_reboot, + .ident = "Dell OptiPlex 990", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"), + }, + }, + { /* Handle problems with rebooting on the Precision M6600. */ + .callback = set_pci_reboot, + .ident = "Dell OptiPlex 990", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "Precision M6600"), + }, + }, + { /* Handle problems with rebooting on the Dell PowerEdge C6100. */ + .callback = set_pci_reboot, + .ident = "Dell PowerEdge C6100", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "C6100"), + }, + }, + { /* Some C6100 machines were shipped with vendor being 'Dell'. */ + .callback = set_pci_reboot, + .ident = "Dell PowerEdge C6100", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell"), + DMI_MATCH(DMI_PRODUCT_NAME, "C6100"), + }, + }, + { } +}; + +static int __init reboot_init(void) +{ + /* + * Only do the DMI check if reboot_type hasn't been overridden + * on the command line + */ + if (reboot_default) + dmi_check_system(reboot_dmi_table); + return 0; +} +core_initcall(reboot_init); + +static inline void kb_wait(void) +{ + int i; + + for (i = 0; i < 0x10000; i++) { + if ((inb(0x64) & 0x02) == 0) + break; + udelay(2); + } +} + +static void vmxoff_nmi(int cpu, struct pt_regs *regs) +{ + cpu_emergency_vmxoff(); +} + +/* Use NMIs as IPIs to tell all CPUs to disable virtualization */ +static void emergency_vmx_disable_all(void) +{ + /* Just make sure we won't change CPUs while doing this */ + local_irq_disable(); + + /* + * We need to disable VMX on all CPUs before rebooting, otherwise + * we risk hanging up the machine, because the CPU ignore INIT + * signals when VMX is enabled. + * + * We can't take any locks and we may be on an inconsistent + * state, so we use NMIs as IPIs to tell the other CPUs to disable + * VMX and halt. + * + * For safety, we will avoid running the nmi_shootdown_cpus() + * stuff unnecessarily, but we don't have a way to check + * if other CPUs have VMX enabled. So we will call it only if the + * CPU we are running on has VMX enabled. + * + * We will miss cases where VMX is not enabled on all CPUs. This + * shouldn't do much harm because KVM always enable VMX on all + * CPUs anyway. But we can miss it on the small window where KVM + * is still enabling VMX. + */ + if (cpu_has_vmx() && cpu_vmx_enabled()) { + /* Disable VMX on this CPU. */ + cpu_vmxoff(); + + /* Halt and disable VMX on the other CPUs */ + nmi_shootdown_cpus(vmxoff_nmi); + + } +} + + +void __attribute__((weak)) mach_reboot_fixups(void) +{ +} + +/* + * Windows compatible x86 hardware expects the following on reboot: + * + * 1) If the FADT has the ACPI reboot register flag set, try it + * 2) If still alive, write to the keyboard controller + * 3) If still alive, write to the ACPI reboot register again + * 4) If still alive, write to the keyboard controller again + * + * If the machine is still alive at this stage, it gives up. We default to + * following the same pattern, except that if we're still alive after (4) we'll + * try to force a triple fault and then cycle between hitting the keyboard + * controller and doing that + */ +static void native_machine_emergency_restart(void) +{ + int i; + int attempt = 0; + int orig_reboot_type = reboot_type; + unsigned short mode; + + if (reboot_emergency) + emergency_vmx_disable_all(); + + tboot_shutdown(TB_SHUTDOWN_REBOOT); + + /* Tell the BIOS if we want cold or warm reboot */ + mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0; + *((unsigned short *)__va(0x472)) = mode; + + for (;;) { + /* Could also try the reset bit in the Hammer NB */ + switch (reboot_type) { + case BOOT_KBD: + mach_reboot_fixups(); /* For board specific fixups */ + + for (i = 0; i < 10; i++) { + kb_wait(); + udelay(50); + outb(0xfe, 0x64); /* Pulse reset low */ + udelay(50); + } + if (attempt == 0 && orig_reboot_type == BOOT_ACPI) { + attempt = 1; + reboot_type = BOOT_ACPI; + } else { + reboot_type = BOOT_TRIPLE; + } + break; + + case BOOT_TRIPLE: + load_idt(&no_idt); + __asm__ __volatile__("int3"); + + reboot_type = BOOT_KBD; + break; + + case BOOT_BIOS: + machine_real_restart(MRR_BIOS); + + reboot_type = BOOT_KBD; + break; + + case BOOT_ACPI: + acpi_reboot(); + reboot_type = BOOT_KBD; + break; + + case BOOT_EFI: + if (efi_enabled(EFI_RUNTIME_SERVICES)) + efi.reset_system(reboot_mode == REBOOT_WARM ? + EFI_RESET_WARM : + EFI_RESET_COLD, + EFI_SUCCESS, 0, NULL); + reboot_type = BOOT_KBD; + break; + + case BOOT_CF9: + port_cf9_safe = true; + /* Fall through */ + + case BOOT_CF9_COND: + if (port_cf9_safe) { + u8 cf9 = inb(0xcf9) & ~6; + outb(cf9|2, 0xcf9); /* Request hard reset */ + udelay(50); + outb(cf9|6, 0xcf9); /* Actually do the reset */ + udelay(50); + } + reboot_type = BOOT_KBD; + break; + } + } +} + +void native_machine_shutdown(void) +{ + /* Stop the cpus and apics */ +#ifdef CONFIG_SMP + + /* The boot cpu is always logical cpu 0 */ + int reboot_cpu_id = 0; + + /* See if there has been given a command line override */ + if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) && + cpu_online(reboot_cpu)) + reboot_cpu_id = reboot_cpu; + + /* Make certain the cpu I'm about to reboot on is online */ + if (!cpu_online(reboot_cpu_id)) + reboot_cpu_id = smp_processor_id(); + + /* Make certain I only run on the appropriate processor */ + set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id)); + + /* + * O.K Now that I'm on the appropriate processor, stop all of the + * others. Also disable the local irq to not receive the per-cpu + * timer interrupt which may trigger scheduler's load balance. + */ + local_irq_disable(); + stop_other_cpus(); +#endif + + lapic_shutdown(); + +#ifdef CONFIG_X86_IO_APIC + disable_IO_APIC(); +#endif + +#ifdef CONFIG_HPET_TIMER + hpet_disable(); +#endif + +#ifdef CONFIG_X86_64 + x86_platform.iommu_shutdown(); +#endif +} + +static void __machine_emergency_restart(int emergency) +{ + reboot_emergency = emergency; + machine_ops.emergency_restart(); +} + +static void native_machine_restart(char *__unused) +{ + pr_notice("machine restart\n"); + + if (!reboot_force) + machine_shutdown(); + __machine_emergency_restart(0); +} + +static void native_machine_halt(void) +{ + /* Stop other cpus and apics */ + machine_shutdown(); + + tboot_shutdown(TB_SHUTDOWN_HALT); + + stop_this_cpu(NULL); +} + +static void native_machine_power_off(void) +{ + if (pm_power_off) { + if (!reboot_force) + machine_shutdown(); + pm_power_off(); + } + /* A fallback in case there is no PM info available */ + tboot_shutdown(TB_SHUTDOWN_HALT); +} + +struct machine_ops machine_ops = { + .power_off = native_machine_power_off, + .shutdown = native_machine_shutdown, + .emergency_restart = native_machine_emergency_restart, + .restart = native_machine_restart, + .halt = native_machine_halt, +#ifdef CONFIG_KEXEC + .crash_shutdown = native_machine_crash_shutdown, +#endif +}; + +void machine_power_off(void) +{ + machine_ops.power_off(); +} + +void machine_shutdown(void) +{ + machine_ops.shutdown(); +} + +void machine_emergency_restart(void) +{ + __machine_emergency_restart(1); +} + +void machine_restart(char *cmd) +{ + machine_ops.restart(cmd); +} + +void machine_halt(void) +{ + machine_ops.halt(); +} + +#ifdef CONFIG_KEXEC +void machine_crash_shutdown(struct pt_regs *regs) +{ + machine_ops.crash_shutdown(regs); +} +#endif + + +#if defined(CONFIG_SMP) + +/* This keeps a track of which one is crashing cpu. */ +static int crashing_cpu; +static nmi_shootdown_cb shootdown_callback; + +static atomic_t waiting_for_crash_ipi; + +static int crash_nmi_callback(unsigned int val, struct pt_regs *regs) +{ + int cpu; + + cpu = raw_smp_processor_id(); + + /* + * Don't do anything if this handler is invoked on crashing cpu. + * Otherwise, system will completely hang. Crashing cpu can get + * an NMI if system was initially booted with nmi_watchdog parameter. + */ + if (cpu == crashing_cpu) + return NMI_HANDLED; + local_irq_disable(); + + shootdown_callback(cpu, regs); + + atomic_dec(&waiting_for_crash_ipi); + /* Assume hlt works */ + halt(); + for (;;) + cpu_relax(); + + return NMI_HANDLED; +} + +static void smp_send_nmi_allbutself(void) +{ + apic->send_IPI_allbutself(NMI_VECTOR); +} + +/* + * Halt all other CPUs, calling the specified function on each of them + * + * This function can be used to halt all other CPUs on crash + * or emergency reboot time. The function passed as parameter + * will be called inside a NMI handler on all CPUs. + */ +void nmi_shootdown_cpus(nmi_shootdown_cb callback) +{ + unsigned long msecs; + local_irq_disable(); + + /* Make a note of crashing cpu. Will be used in NMI callback. */ + crashing_cpu = safe_smp_processor_id(); + + shootdown_callback = callback; + + atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); + /* Would it be better to replace the trap vector here? */ + if (register_nmi_handler(NMI_LOCAL, crash_nmi_callback, + NMI_FLAG_FIRST, "crash")) + return; /* Return what? */ + /* + * Ensure the new callback function is set before sending + * out the NMI + */ + wmb(); + + smp_send_nmi_allbutself(); + + msecs = 1000; /* Wait at most a second for the other cpus to stop */ + while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) { + mdelay(1); + msecs--; + } + + /* Leave the nmi callback set */ +} +#else /* !CONFIG_SMP */ +void nmi_shootdown_cpus(nmi_shootdown_cb callback) +{ + /* No other CPUs to shoot down */ +} +#endif |