xtensa: nommu support
Add support for !CONFIG_MMU setups.
Signed-off-by: Johannes Weiner <jw@emlix.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
diff --git a/arch/xtensa/mm/mmu.c b/arch/xtensa/mm/mmu.c
new file mode 100644
index 0000000..4bb91a9
--- /dev/null
+++ b/arch/xtensa/mm/mmu.c
@@ -0,0 +1,70 @@
+/*
+ * xtensa mmu stuff
+ *
+ * Extracted from init.c
+ */
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/cache.h>
+
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
+#include <asm/page.h>
+
+DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
+
+void __init paging_init(void)
+{
+ memset(swapper_pg_dir, 0, PAGE_SIZE);
+}
+
+/*
+ * Flush the mmu and reset associated register to default values.
+ */
+void __init init_mmu(void)
+{
+ /* Writing zeros to the <t>TLBCFG special registers ensure
+ * that valid values exist in the register. For existing
+ * PGSZID<w> fields, zero selects the first element of the
+ * page-size array. For nonexistent PGSZID<w> fields, zero is
+ * the best value to write. Also, when changing PGSZID<w>
+ * fields, the corresponding TLB must be flushed.
+ */
+ set_itlbcfg_register(0);
+ set_dtlbcfg_register(0);
+ flush_tlb_all();
+
+ /* Set rasid register to a known value. */
+
+ set_rasid_register(ASID_USER_FIRST);
+
+ /* Set PTEVADDR special register to the start of the page
+ * table, which is in kernel mappable space (ie. not
+ * statically mapped). This register's value is undefined on
+ * reset.
+ */
+ set_ptevaddr_register(PGTABLE_START);
+}
+
+struct kmem_cache *pgtable_cache __read_mostly;
+
+static void pgd_ctor(void *addr)
+{
+ pte_t *ptep = (pte_t *)addr;
+ int i;
+
+ for (i = 0; i < 1024; i++, ptep++)
+ pte_clear(NULL, 0, ptep);
+
+}
+
+void __init pgtable_cache_init(void)
+{
+ pgtable_cache = kmem_cache_create("pgd",
+ PAGE_SIZE, PAGE_SIZE,
+ SLAB_HWCACHE_ALIGN,
+ pgd_ctor);
+}