| /* |
| * Architecture specific (i386/x86_64) functions for kexec based crash dumps. |
| * |
| * Created by: Hariprasad Nellitheertha (hari@in.ibm.com) |
| * |
| * Copyright (C) IBM Corporation, 2004. All rights reserved. |
| * |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/types.h> |
| #include <linux/kernel.h> |
| #include <linux/smp.h> |
| #include <linux/reboot.h> |
| #include <linux/kexec.h> |
| #include <linux/delay.h> |
| #include <linux/elf.h> |
| #include <linux/elfcore.h> |
| |
| #include <asm/processor.h> |
| #include <asm/hardirq.h> |
| #include <asm/nmi.h> |
| #include <asm/hw_irq.h> |
| #include <asm/apic.h> |
| #include <linux/kdebug.h> |
| #include <asm/smp.h> |
| |
| #ifdef X86_32 |
| #include <mach_ipi.h> |
| #else |
| #include <asm/mach_apic.h> |
| #endif |
| |
| /* This keeps a track of which one is crashing cpu. */ |
| static int crashing_cpu; |
| |
| #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC) |
| static atomic_t waiting_for_crash_ipi; |
| |
| static int crash_nmi_callback(struct notifier_block *self, |
| unsigned long val, void *data) |
| { |
| struct pt_regs *regs; |
| #ifdef X86_32 |
| struct pt_regs fixed_regs; |
| #endif |
| int cpu; |
| |
| if (val != DIE_NMI_IPI) |
| return NOTIFY_OK; |
| |
| regs = ((struct die_args *)data)->regs; |
| 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 NOTIFY_STOP; |
| local_irq_disable(); |
| |
| #ifdef X86_32 |
| if (!user_mode_vm(regs)) { |
| crash_fixup_ss_esp(&fixed_regs, regs); |
| regs = &fixed_regs; |
| } |
| #endif |
| crash_save_cpu(regs, cpu); |
| disable_local_APIC(); |
| atomic_dec(&waiting_for_crash_ipi); |
| /* Assume hlt works */ |
| halt(); |
| for (;;) |
| cpu_relax(); |
| |
| return 1; |
| } |
| |
| static void smp_send_nmi_allbutself(void) |
| { |
| cpumask_t mask = cpu_online_map; |
| cpu_clear(safe_smp_processor_id(), mask); |
| if (!cpus_empty(mask)) |
| send_IPI_mask(mask, NMI_VECTOR); |
| } |
| |
| static struct notifier_block crash_nmi_nb = { |
| .notifier_call = crash_nmi_callback, |
| }; |
| |
| static void nmi_shootdown_cpus(void) |
| { |
| unsigned long msecs; |
| |
| atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1); |
| /* Would it be better to replace the trap vector here? */ |
| if (register_die_notifier(&crash_nmi_nb)) |
| 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 */ |
| disable_local_APIC(); |
| } |
| #else |
| static void nmi_shootdown_cpus(void) |
| { |
| /* There are no cpus to shootdown */ |
| } |
| #endif |
| |
| void machine_crash_shutdown(struct pt_regs *regs) |
| { |
| /* This function is only called after the system |
| * has panicked or is otherwise in a critical state. |
| * The minimum amount of code to allow a kexec'd kernel |
| * to run successfully needs to happen here. |
| * |
| * In practice this means shooting down the other cpus in |
| * an SMP system. |
| */ |
| /* The kernel is broken so disable interrupts */ |
| local_irq_disable(); |
| |
| /* Make a note of crashing cpu. Will be used in NMI callback.*/ |
| crashing_cpu = safe_smp_processor_id(); |
| nmi_shootdown_cpus(); |
| lapic_shutdown(); |
| #if defined(CONFIG_X86_IO_APIC) |
| disable_IO_APIC(); |
| #endif |
| crash_save_cpu(regs, safe_smp_processor_id()); |
| } |