crash.c

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/*
 * Architecture specific (i386/x86_64) functions for kexec based crash dumps.
 *
 * Created by: Hariprasad Nellitheertha ([email protected])
 *
 * 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 <asm/hpet.h>
#include <linux/kdebug.h>
#include <asm/cpu.h>
#include <asm/reboot.h>
#include <asm/virtext.h>

int in_crash_kexec;

#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)

static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
{
#ifdef CONFIG_X86_32
    struct pt_regs fixed_regs;
#endif

#ifdef CONFIG_X86_32
    if (!user_mode_vm(regs)) {
        crash_fixup_ss_esp(&fixed_regs, regs);
        regs = &fixed_regs;
    }
#endif
    crash_save_cpu(regs, cpu);

    /* Disable VMX or SVM if needed.
     *
     * We need to disable virtualization on all CPUs.
     * Having VMX or SVM enabled on any CPU may break rebooting
     * after the kdump kernel has finished its task.
     */
    cpu_emergency_vmxoff();
    cpu_emergency_svm_disable();

    disable_local_APIC();
}

static void kdump_nmi_shootdown_cpus(void)
{
    in_crash_kexec = 1;
    nmi_shootdown_cpus(kdump_nmi_callback);

    disable_local_APIC();
}

#else
static void kdump_nmi_shootdown_cpus(void)
{
    /* There are no cpus to shootdown */
}
#endif

void native_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();

    kdump_nmi_shootdown_cpus();

    /* Booting kdump kernel with VMX or SVM enabled won't work,
     * because (among other limitations) we can't disable paging
     * with the virt flags.
     */
    cpu_emergency_vmxoff();
    cpu_emergency_svm_disable();

    lapic_shutdown();
#if defined(CONFIG_X86_IO_APIC)
    disable_IO_APIC();
#endif
#ifdef CONFIG_HPET_TIMER
    hpet_disable();
#endif
    crash_save_cpu(regs, safe_smp_processor_id());
}