136 lines
3.0 KiB
C
136 lines
3.0 KiB
C
/*
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* Architecture specific (x86_64) functions for kexec based crash dumps.
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*
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* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
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*
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* Copyright (C) IBM Corporation, 2004. All rights reserved.
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*
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*/
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/smp.h>
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#include <linux/irq.h>
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#include <linux/reboot.h>
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#include <linux/kexec.h>
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#include <linux/delay.h>
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#include <linux/elf.h>
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#include <linux/elfcore.h>
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#include <linux/kdebug.h>
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#include <asm/processor.h>
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#include <asm/hardirq.h>
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#include <asm/nmi.h>
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#include <asm/hw_irq.h>
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#include <asm/mach_apic.h>
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/* This keeps a track of which one is crashing cpu. */
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static int crashing_cpu;
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#ifdef CONFIG_SMP
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static atomic_t waiting_for_crash_ipi;
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static int crash_nmi_callback(struct notifier_block *self,
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unsigned long val, void *data)
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{
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struct pt_regs *regs;
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int cpu;
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if (val != DIE_NMI_IPI)
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return NOTIFY_OK;
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regs = ((struct die_args *)data)->regs;
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cpu = raw_smp_processor_id();
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/*
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* Don't do anything if this handler is invoked on crashing cpu.
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* Otherwise, system will completely hang. Crashing cpu can get
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* an NMI if system was initially booted with nmi_watchdog parameter.
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*/
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if (cpu == crashing_cpu)
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return NOTIFY_STOP;
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local_irq_disable();
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crash_save_cpu(regs, cpu);
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disable_local_APIC();
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atomic_dec(&waiting_for_crash_ipi);
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/* Assume hlt works */
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for(;;)
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halt();
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return 1;
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}
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static void smp_send_nmi_allbutself(void)
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{
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send_IPI_allbutself(NMI_VECTOR);
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}
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/*
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* This code is a best effort heuristic to get the
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* other cpus to stop executing. So races with
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* cpu hotplug shouldn't matter.
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*/
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static struct notifier_block crash_nmi_nb = {
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.notifier_call = crash_nmi_callback,
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};
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static void nmi_shootdown_cpus(void)
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{
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unsigned long msecs;
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atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
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if (register_die_notifier(&crash_nmi_nb))
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return; /* return what? */
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/*
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* Ensure the new callback function is set before sending
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* out the NMI
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*/
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wmb();
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smp_send_nmi_allbutself();
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msecs = 1000; /* Wait at most a second for the other cpus to stop */
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while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
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mdelay(1);
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msecs--;
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}
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/* Leave the nmi callback set */
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disable_local_APIC();
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}
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#else
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static void nmi_shootdown_cpus(void)
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{
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/* There are no cpus to shootdown */
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}
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#endif
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void machine_crash_shutdown(struct pt_regs *regs)
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{
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/*
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* This function is only called after the system
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* has panicked or is otherwise in a critical state.
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* The minimum amount of code to allow a kexec'd kernel
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* to run successfully needs to happen here.
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*
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* In practice this means shooting down the other cpus in
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* an SMP system.
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*/
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/* The kernel is broken so disable interrupts */
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local_irq_disable();
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/* Make a note of crashing cpu. Will be used in NMI callback.*/
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crashing_cpu = smp_processor_id();
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nmi_shootdown_cpus();
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if(cpu_has_apic)
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disable_local_APIC();
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disable_IO_APIC();
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crash_save_cpu(regs, smp_processor_id());
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}
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