1 files changed, 135 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/crash_64.c b/arch/x86_64/kernel/crash_64.c
new file mode 100644
index 0000000..13432a1
--- /dev/null
+++ b/arch/x86_64/kernel/crash_64.c
@@ -0,0 +1,135 @@
+/*
+ * Architecture specific (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/irq.h>
+#include <linux/reboot.h>
+#include <linux/kexec.h>
+#include <linux/delay.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/kdebug.h>
+
+#include <asm/processor.h>
+#include <asm/hardirq.h>
+#include <asm/nmi.h>
+#include <asm/hw_irq.h>
+#include <asm/mach_apic.h>
+
+/* This keeps a track of which one is crashing cpu. */
+static int crashing_cpu;
+
+#ifdef CONFIG_SMP
+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;
+	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();
+
+	crash_save_cpu(regs, cpu);
+	disable_local_APIC();
+	atomic_dec(&waiting_for_crash_ipi);
+	/* Assume hlt works */
+	for(;;)
+		halt();
+
+	return 1;
+}
+
+static void smp_send_nmi_allbutself(void)
+{
+	send_IPI_allbutself(NMI_VECTOR);
+}
+
+/*
+ * This code is a best effort heuristic to get the
+ * other cpus to stop executing. So races with
+ * cpu hotplug shouldn't matter.
+ */
+
+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);
+	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 = smp_processor_id();
+	nmi_shootdown_cpus();
+
+	if(cpu_has_apic)
+		 disable_local_APIC();
+
+	disable_IO_APIC();
+
+	crash_save_cpu(regs, smp_processor_id());
+}