sh: cache secondary CPUs idle loop.

This provides a cache of the secondary CPUs idle loop for the cases where
hotplug simply enters a low power state instead of resetting or powering
off the core.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

2 files changed, 13 insertions, 4 deletions

diff --git a/arch/sh/include/asm/processor.h b/arch/sh/include/asm/processor.h
index 26b3f026eec9..0a58cb25a658 100644
--- a/arch/sh/include/asm/processor.h
+++ b/arch/sh/include/asm/processor.h
@@ -85,6 +85,10 @@ struct sh_cpuinfo {
         struct tlb_info itlb;
         struct tlb_info dtlb;
 
+#ifdef CONFIG_SMP
+        struct task_struct *idle;
+#endif
+
         unsigned long flags;
 } __attribute__ ((aligned(L1_CACHE_BYTES)));
 
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 3711a76a18e0..21e7f8a9f3e4 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -125,10 +125,15 @@ int __cpuinit __cpu_up(unsigned int cpu)
         struct task_struct *tsk;
         unsigned long timeout;
 
-        tsk = fork_idle(cpu);
-        if (IS_ERR(tsk)) {
-                printk(KERN_ERR "Failed forking idle task for cpu %d\n", cpu);
-                return PTR_ERR(tsk);
+        tsk = cpu_data[cpu].idle;
+        if (!tsk) {
+                tsk = fork_idle(cpu);
+                if (IS_ERR(tsk)) {
+                        pr_err("Failed forking idle task for cpu %d\n", cpu);
+                        return PTR_ERR(tsk);
+                }
+
+                cpu_data[cpu].idle = tsk;
         }
 
         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;