#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>
-note_buf_t crash_notes[NR_CPUS];
+/* 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 paniced or is otherwise in a critical state.
+ /*
+ * 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());
}