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/*
* Architecture specific (i386) 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/irq.h>
#include <linux/reboot.h>
#include <linux/kexec.h>
#include <linux/irq.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 <mach_ipi.h>
#define MAX_NOTE_BYTES 1024
typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
note_buf_t crash_notes[NR_CPUS];
#ifdef CONFIG_SMP
static atomic_t waiting_for_crash_ipi;
static int crash_nmi_callback(struct pt_regs *regs, int cpu)
{
local_irq_disable();
atomic_dec(&waiting_for_crash_ipi);
/* Assume hlt works */
__asm__("hlt");
for(;;);
return 1;
}
/*
* By using the NMI code instead of a vector we just sneak thru the
* word generator coming out with just what we want. AND it does
* not matter if clustered_apic_mode is set or not.
*/
static void smp_send_nmi_allbutself(void)
{
send_IPI_allbutself(APIC_DM_NMI);
}
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? */
set_nmi_callback(crash_nmi_callback);
/* 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
static void nmi_shootdown_cpus(void)
{
/* There are no cpus to shootdown */
}
#endif
void machine_crash_shutdown(void)
{
/* This function is only called after the system
* has paniced 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();
nmi_shootdown_cpus();
}
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