[MIPS] Symmetric Uniprocessor support for Qemu.

SMP bits needed to builds and run an SMP kernel.  While only a single
processor is supported ATM it's still useful for some SMP debugging using
Qemu.
    
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -1582,7 +1582,7 @@ source "mm/Kconfig"
 
 config SMP
 	bool "Multi-Processing support"
-	depends on CPU_RM9000 || ((SIBYTE_BCM1x80 || SIBYTE_BCM1x55 || SIBYTE_SB1250) && !SIBYTE_STANDALONE) || SGI_IP27 || MIPS_MT_SMP
+	depends on CPU_RM9000 || ((SIBYTE_BCM1x80 || SIBYTE_BCM1x55 || SIBYTE_SB1250 || QEMU) && !SIBYTE_STANDALONE) || SGI_IP27 || MIPS_MT_SMP
 	---help---
 	  This enables support for systems with more than one CPU. If you have
 	  a system with only one CPU, like most personal computers, say N. If

arch/mips/qemu/Makefile

@@ -3,3 +3,5 @@
 #
 
 obj-y		= q-firmware.o q-int.o q-irq.o q-mem.o q-setup.o
+
+obj-$(CONFIG_SMP) += q-smp.o

arch/mips/qemu/q-smp.c

@@ -0,0 +1,48 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2006 by Ralf Baechle (ralf@linux-mips.org)
+ *
+ * Symmetric Uniprocessor (TM) Support
+ */
+#include <linux/kernel.h>
+#include <linux/sched.h>
+
+/*
+ * Send inter-processor interrupt
+ */
+void core_send_ipi(int cpu, unsigned int action)
+{
+	panic(KERN_ERR "%s called", __FUNCTION__);
+}
+
+/*
+ *  After we've done initial boot, this function is called to allow the
+ *  board code to clean up state, if needed
+ */
+void prom_init_secondary(void)
+{
+}
+
+void prom_smp_finish(void)
+{
+}
+
+/* Hook for after all CPUs are online */
+void prom_cpus_done(void)
+{
+}
+
+void __init prom_prepare_cpus(unsigned int max_cpus)
+{
+	cpus_clear(phys_cpu_present_map);
+}
+
+/*
+ * Firmware CPU startup hook
+ */
+void prom_boot_secondary(int cpu, struct task_struct *idle)
+{
+}