1 files changed, 141 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/mmu_context.h b/arch/xtensa/include/asm/mmu_context.h
new file mode 100644
index 00000000..dbd8731a
--- /dev/null
+++ b/arch/xtensa/include/asm/mmu_context.h
@@ -0,0 +1,141 @@
+/*
+ * include/asm-xtensa/mmu_context.h
+ *
+ * Switch an MMU context.
+ *
+ * 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) 2001 - 2005 Tensilica Inc.
+ */
+
+#ifndef _XTENSA_MMU_CONTEXT_H
+#define _XTENSA_MMU_CONTEXT_H
+
+#ifndef CONFIG_MMU
+#include <asm/nommu_context.h>
+#else
+
+#include <linux/stringify.h>
+#include <linux/sched.h>
+
+#include <variant/core.h>
+
+#include <asm/pgtable.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm-generic/mm_hooks.h>
+
+#if (XCHAL_HAVE_TLBS != 1)
+# error "Linux must have an MMU!"
+#endif
+
+extern unsigned long asid_cache;
+
+/*
+ * NO_CONTEXT is the invalid ASID value that we don't ever assign to
+ * any user or kernel context.
+ *
+ * 0 invalid
+ * 1 kernel
+ * 2 reserved
+ * 3 reserved
+ * 4...255 available
+ */
+
+#define NO_CONTEXT	0
+#define ASID_USER_FIRST	4
+#define ASID_MASK	((1 << XCHAL_MMU_ASID_BITS) - 1)
+#define ASID_INSERT(x)	(0x03020001 | (((x) & ASID_MASK) << 8))
+
+static inline void set_rasid_register (unsigned long val)
+{
+	__asm__ __volatile__ (" wsr %0, "__stringify(RASID)"\n\t"
+			      " isync\n" : : "a" (val));
+}
+
+static inline unsigned long get_rasid_register (void)
+{
+	unsigned long tmp;
+	__asm__ __volatile__ (" rsr %0,"__stringify(RASID)"\n\t" : "=a" (tmp));
+	return tmp;
+}
+
+static inline void
+__get_new_mmu_context(struct mm_struct *mm)
+{
+	extern void flush_tlb_all(void);
+	if (! (++asid_cache & ASID_MASK) ) {
+		flush_tlb_all(); /* start new asid cycle */
+		asid_cache += ASID_USER_FIRST;
+	}
+	mm->context = asid_cache;
+}
+
+static inline void
+__load_mmu_context(struct mm_struct *mm)
+{
+	set_rasid_register(ASID_INSERT(mm->context));
+	invalidate_page_directory();
+}
+
+/*
+ * Initialize the context related info for a new mm_struct
+ * instance.
+ */
+
+static inline int
+init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+	mm->context = NO_CONTEXT;
+	return 0;
+}
+
+/*
+ * After we have set current->mm to a new value, this activates
+ * the context for the new mm so we see the new mappings.
+ */
+static inline void
+activate_mm(struct mm_struct *prev, struct mm_struct *next)
+{
+	/* Unconditionally get a new ASID.  */
+
+	__get_new_mmu_context(next);
+	__load_mmu_context(next);
+}
+
+
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+                             struct task_struct *tsk)
+{
+	unsigned long asid = asid_cache;
+
+	/* Check if our ASID is of an older version and thus invalid */
+
+	if (next->context == NO_CONTEXT || ((next->context^asid) & ~ASID_MASK))
+		__get_new_mmu_context(next);
+
+	__load_mmu_context(next);
+}
+
+#define deactivate_mm(tsk, mm)	do { } while(0)
+
+/*
+ * Destroy context related info for an mm_struct that is about
+ * to be put to rest.
+ */
+static inline void destroy_context(struct mm_struct *mm)
+{
+	invalidate_page_directory();
+}
+
+
+static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
+{
+	/* Nothing to do. */
+
+}
+
+#endif /* CONFIG_MMU */
+#endif /* _XTENSA_MMU_CONTEXT_H */