1 files changed, 117 insertions, 0 deletions
diff --git a/arch/arm/include/asm/mmu_context.h b/arch/arm/include/asm/mmu_context.h
new file mode 100644
index 00000000000..a301e446007
--- /dev/null
+++ b/arch/arm/include/asm/mmu_context.h
@@ -0,0 +1,117 @@
+/*
+ *  arch/arm/include/asm/mmu_context.h
+ *
+ *  Copyright (C) 1996 Russell King.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  Changelog:
+ *   27-06-1996	RMK	Created
+ */
+#ifndef __ASM_ARM_MMU_CONTEXT_H
+#define __ASM_ARM_MMU_CONTEXT_H
+
+#include <linux/compiler.h>
+#include <asm/cacheflush.h>
+#include <asm/proc-fns.h>
+#include <asm-generic/mm_hooks.h>
+
+void __check_kvm_seq(struct mm_struct *mm);
+
+#ifdef CONFIG_CPU_HAS_ASID
+
+/*
+ * On ARMv6, we have the following structure in the Context ID:
+ *
+ * 31                         7          0
+ * +-------------------------+-----------+
+ * |      process ID         |   ASID    |
+ * +-------------------------+-----------+
+ * |              context ID             |
+ * +-------------------------------------+
+ *
+ * The ASID is used to tag entries in the CPU caches and TLBs.
+ * The context ID is used by debuggers and trace logic, and
+ * should be unique within all running processes.
+ */
+#define ASID_BITS		8
+#define ASID_MASK		((~0) << ASID_BITS)
+#define ASID_FIRST_VERSION	(1 << ASID_BITS)
+
+extern unsigned int cpu_last_asid;
+
+void __init_new_context(struct task_struct *tsk, struct mm_struct *mm);
+void __new_context(struct mm_struct *mm);
+
+static inline void check_context(struct mm_struct *mm)
+{
+	if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS))
+		__new_context(mm);
+
+	if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
+		__check_kvm_seq(mm);
+}
+
+#define init_new_context(tsk,mm)	(__init_new_context(tsk,mm),0)
+
+#else
+
+static inline void check_context(struct mm_struct *mm)
+{
+	if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
+		__check_kvm_seq(mm);
+}
+
+#define init_new_context(tsk,mm)	0
+
+#endif
+
+#define destroy_context(mm)		do { } while(0)
+
+/*
+ * This is called when "tsk" is about to enter lazy TLB mode.
+ *
+ * mm:  describes the currently active mm context
+ * tsk: task which is entering lazy tlb
+ * cpu: cpu number which is entering lazy tlb
+ *
+ * tsk->mm will be NULL
+ */
+static inline void
+enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
+{
+}
+
+/*
+ * This is the actual mm switch as far as the scheduler
+ * is concerned.  No registers are touched.  We avoid
+ * calling the CPU specific function when the mm hasn't
+ * actually changed.
+ */
+static inline void
+switch_mm(struct mm_struct *prev, struct mm_struct *next,
+	  struct task_struct *tsk)
+{
+#ifdef CONFIG_MMU
+	unsigned int cpu = smp_processor_id();
+
+#ifdef CONFIG_SMP
+	/* check for possible thread migration */
+	if (!cpus_empty(next->cpu_vm_mask) && !cpu_isset(cpu, next->cpu_vm_mask))
+		__flush_icache_all();
+#endif
+	if (!cpu_test_and_set(cpu, next->cpu_vm_mask) || prev != next) {
+		check_context(next);
+		cpu_switch_mm(next->pgd, next);
+		if (cache_is_vivt())
+			cpu_clear(cpu, prev->cpu_vm_mask);
+	}
+#endif
+}
+
+#define deactivate_mm(tsk,mm)	do { } while (0)
+#define activate_mm(prev,next)	switch_mm(prev, next, NULL)
+
+#endif