sh: Always provide thread_info allocators.

Presently the thread_info allocators are special cased, depending on
THREAD_SHIFT < PAGE_SHIFT. This provides a sensible definition for them
regardless of configuration, in preparation for extended CPU state.

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

arch/sh/kernel/process.c

@@ -0,0 +1,47 @@
+#include <linux/mm.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+
+#if THREAD_SHIFT < PAGE_SHIFT
+static struct kmem_cache *thread_info_cache;
+
+struct thread_info *alloc_thread_info(struct task_struct *tsk)
+{
+	struct thread_info *ti;
+
+	ti = kmem_cache_alloc(thread_info_cache, GFP_KERNEL);
+	if (unlikely(ti == NULL))
+		return NULL;
+#ifdef CONFIG_DEBUG_STACK_USAGE
+	memset(ti, 0, THREAD_SIZE);
+#endif
+	return ti;
+}
+
+void free_thread_info(struct thread_info *ti)
+{
+	kmem_cache_free(thread_info_cache, ti);
+}
+
+void thread_info_cache_init(void)
+{
+	thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
+					      THREAD_SIZE, 0, NULL);
+	BUG_ON(thread_info_cache == NULL);
+}
+#else
+struct thread_info *alloc_thread_info(struct task_struct *tsk)
+{
+#ifdef CONFIG_DEBUG_STACK_USAGE
+	gfp_t mask = GFP_KERNEL | __GFP_ZERO;
+#else
+	gfp_t mask = GFP_KERNEL;
+#endif
+	return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER);
+}
+
+void free_thread_info(struct thread_info *ti)
+{
+	free_pages((unsigned long)ti, THREAD_SIZE_ORDER);
+}
+#endif /* THREAD_SHIFT < PAGE_SHIFT */