mips: Use generic idle thread allocation

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Link: http://lkml.kernel.org/r/20120420124557.512158271@linutronix.de

arch/mips/Kconfig

@@ -29,6 +29,7 @@ config MIPS
 	select HAVE_MEMBLOCK
 	select HAVE_MEMBLOCK_NODE_MAP
 	select ARCH_DISCARD_MEMBLOCK
+	select GENERIC_SMP_IDLE_THREAD
 
 menu "Machine selection"
 

arch/mips/kernel/smp.c

@@ -186,61 +186,9 @@ void __devinit smp_prepare_boot_cpu(void)
 	cpu_set(0, cpu_callin_map);
 }
 
-/*
- * Called once for each "cpu_possible(cpu)".  Needs to spin up the cpu
- * and keep control until "cpu_online(cpu)" is set.  Note: cpu is
- * physical, not logical.
- */
-static struct task_struct *cpu_idle_thread[NR_CPUS];
-
-struct create_idle {
-	struct work_struct work;
-	struct task_struct *idle;
-	struct completion done;
-	int cpu;
-};
-
-static void __cpuinit do_fork_idle(struct work_struct *work)
-{
-	struct create_idle *c_idle =
-		container_of(work, struct create_idle, work);
-
-	c_idle->idle = fork_idle(c_idle->cpu);
-	complete(&c_idle->done);
-}
-
 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 {
-	struct task_struct *idle;
-
-	/*
-	 * Processor goes to start_secondary(), sets online flag
-	 * The following code is purely to make sure
-	 * Linux can schedule processes on this slave.
-	 */
-	if (!cpu_idle_thread[cpu]) {
-		/*
-		 * Schedule work item to avoid forking user task
-		 * Ported from arch/x86/kernel/smpboot.c
-		 */
-		struct create_idle c_idle = {
-			.cpu    = cpu,
-			.done   = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
-		};
-
-		INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
-		schedule_work(&c_idle.work);
-		wait_for_completion(&c_idle.done);
-		idle = cpu_idle_thread[cpu] = c_idle.idle;
-
-		if (IS_ERR(idle))
-			panic(KERN_ERR "Fork failed for CPU %d", cpu);
-	} else {
-		idle = cpu_idle_thread[cpu];
-		init_idle(idle, cpu);
-	}
-
-	mp_ops->boot_secondary(cpu, idle);
+	mp_ops->boot_secondary(cpu, tidle);
 
 	/*
 	 * Trust is futile.  We should really have timeouts ...