1 files changed, 157 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 000000000..04c8ebdc4
--- /dev/null
+++ b/arch/xtensa/include/asm/mmu_context.h
@@ -0,0 +1,157 @@
+/*
+ * 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 - 2013 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 <asm/vectors.h>
+
+#include <asm/pgtable.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm-generic/mm_hooks.h>
+#include <asm-generic/percpu.h>
+
+#if (XCHAL_HAVE_TLBS != 1)
+# error "Linux must have an MMU!"
+#endif
+
+DECLARE_PER_CPU(unsigned long, asid_cache);
+#define cpu_asid_cache(cpu) per_cpu(asid_cache, cpu)
+
+/*
+ * NO_CONTEXT is the invalid ASID value that we don't ever assign to
+ * any user or kernel context.  We use the reserved values in the
+ * ASID_INSERT macro below.
+ *
+ * 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))
+
+void init_mmu(void);
+
+static inline void set_rasid_register (unsigned long val)
+{
+	__asm__ __volatile__ (" wsr %0, rasid\n\t"
+			      " isync\n" : : "a" (val));
+}
+
+static inline unsigned long get_rasid_register (void)
+{
+	unsigned long tmp;
+	__asm__ __volatile__ (" rsr %0, rasid\n\t" : "=a" (tmp));
+	return tmp;
+}
+
+static inline void get_new_mmu_context(struct mm_struct *mm, unsigned int cpu)
+{
+	unsigned long asid = cpu_asid_cache(cpu);
+	if ((++asid & ASID_MASK) == 0) {
+		/*
+		 * Start new asid cycle; continue counting with next
+		 * incarnation bits; skipping over 0, 1, 2, 3.
+		 */
+		local_flush_tlb_all();
+		asid += ASID_USER_FIRST;
+	}
+	cpu_asid_cache(cpu) = asid;
+	mm->context.asid[cpu] = asid;
+	mm->context.cpu = cpu;
+}
+
+static inline void get_mmu_context(struct mm_struct *mm, unsigned int cpu)
+{
+	/*
+	 * Check if our ASID is of an older version and thus invalid.
+	 */
+
+	if (mm) {
+		unsigned long asid = mm->context.asid[cpu];
+
+		if (asid == NO_CONTEXT ||
+				((asid ^ cpu_asid_cache(cpu)) & ~ASID_MASK))
+			get_new_mmu_context(mm, cpu);
+	}
+}
+
+static inline void activate_context(struct mm_struct *mm, unsigned int cpu)
+{
+	get_mmu_context(mm, cpu);
+	set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
+	invalidate_page_directory();
+}
+
+/*
+ * Initialize the context related info for a new mm_struct
+ * instance.  Valid cpu values are 0..(NR_CPUS-1), so initializing
+ * to -1 says the process has never run on any core.
+ */
+
+static inline int init_new_context(struct task_struct *tsk,
+		struct mm_struct *mm)
+{
+	int cpu;
+	for_each_possible_cpu(cpu) {
+		mm->context.asid[cpu] = NO_CONTEXT;
+	}
+	mm->context.cpu = -1;
+	return 0;
+}
+
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+			     struct task_struct *tsk)
+{
+	unsigned int cpu = smp_processor_id();
+	int migrated = next->context.cpu != cpu;
+	/* Flush the icache if we migrated to a new core. */
+	if (migrated) {
+		__invalidate_icache_all();
+		next->context.cpu = cpu;
+	}
+	if (migrated || prev != next)
+		activate_context(next, cpu);
+}
+
+#define activate_mm(prev, next)	switch_mm((prev), (next), NULL)
+#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 */