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-rw-r--r--arch/x86/kernel/reboot.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 0e3dbc7..ba7b9a0 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -21,6 +21,9 @@
# include <asm/iommu.h>
#endif
+#include <mach_ipi.h>
+
+
/*
* Power off function, if any
*/
@@ -548,3 +551,92 @@ void machine_crash_shutdown(struct pt_regs *regs)
machine_ops.crash_shutdown(regs);
}
#endif
+
+
+#if defined(CONFIG_SMP)
+
+/* This keeps a track of which one is crashing cpu. */
+static int crashing_cpu;
+static nmi_shootdown_cb shootdown_callback;
+
+static atomic_t waiting_for_crash_ipi;
+
+static int crash_nmi_callback(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ int cpu;
+
+ if (val != DIE_NMI_IPI)
+ return NOTIFY_OK;
+
+ 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();
+
+ shootdown_callback(cpu, (struct die_args *)data);
+
+ atomic_dec(&waiting_for_crash_ipi);
+ /* Assume hlt works */
+ halt();
+ for (;;)
+ cpu_relax();
+
+ return 1;
+}
+
+static void smp_send_nmi_allbutself(void)
+{
+ send_IPI_allbutself(NMI_VECTOR);
+}
+
+static struct notifier_block crash_nmi_nb = {
+ .notifier_call = crash_nmi_callback,
+};
+
+/* Halt all other CPUs, calling the specified function on each of them
+ *
+ * This function can be used to halt all other CPUs on crash
+ * or emergency reboot time. The function passed as parameter
+ * will be called inside a NMI handler on all CPUs.
+ */
+void nmi_shootdown_cpus(nmi_shootdown_cb callback)
+{
+ unsigned long msecs;
+ local_irq_disable();
+
+ /* Make a note of crashing cpu. Will be used in NMI callback.*/
+ crashing_cpu = safe_smp_processor_id();
+
+ shootdown_callback = callback;
+
+ atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
+ /* Would it be better to replace the trap vector here? */
+ 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 */
+}
+#else /* !CONFIG_SMP */
+void nmi_shootdown_cpus(nmi_shootdown_cb callback)
+{
+ /* No other CPUs to shoot down */
+}
+#endif
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