1 files changed, 154 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 000000000..f99ed524f
--- /dev/null
+++ b/arch/arm/include/asm/mmu_context.h
@@ -0,0 +1,154 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *  arch/arm/include/asm/mmu_context.h
+ *
+ *  Copyright (C) 1996 Russell King.
+ *
+ *  Changelog:
+ *   27-06-1996	RMK	Created
+ */
+#ifndef __ASM_ARM_MMU_CONTEXT_H
+#define __ASM_ARM_MMU_CONTEXT_H
+
+#include <linux/compiler.h>
+#include <linux/sched.h>
+#include <linux/mm_types.h>
+#include <linux/preempt.h>
+
+#include <asm/cacheflush.h>
+#include <asm/cachetype.h>
+#include <asm/proc-fns.h>
+#include <asm/smp_plat.h>
+#include <asm-generic/mm_hooks.h>
+
+void __check_vmalloc_seq(struct mm_struct *mm);
+
+#ifdef CONFIG_CPU_HAS_ASID
+
+void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk);
+static inline int
+init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+	atomic64_set(&mm->context.id, 0);
+	return 0;
+}
+
+#ifdef CONFIG_ARM_ERRATA_798181
+void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
+			     cpumask_t *mask);
+#else  /* !CONFIG_ARM_ERRATA_798181 */
+static inline void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
+					   cpumask_t *mask)
+{
+}
+#endif /* CONFIG_ARM_ERRATA_798181 */
+
+#else	/* !CONFIG_CPU_HAS_ASID */
+
+#ifdef CONFIG_MMU
+
+static inline void check_and_switch_context(struct mm_struct *mm,
+					    struct task_struct *tsk)
+{
+	if (unlikely(mm->context.vmalloc_seq != init_mm.context.vmalloc_seq))
+		__check_vmalloc_seq(mm);
+
+	if (irqs_disabled())
+		/*
+		 * cpu_switch_mm() needs to flush the VIVT caches. To avoid
+		 * high interrupt latencies, defer the call and continue
+		 * running with the old mm. Since we only support UP systems
+		 * on non-ASID CPUs, the old mm will remain valid until the
+		 * finish_arch_post_lock_switch() call.
+		 */
+		mm->context.switch_pending = 1;
+	else
+		cpu_switch_mm(mm->pgd, mm);
+}
+
+#ifndef MODULE
+#define finish_arch_post_lock_switch \
+	finish_arch_post_lock_switch
+static inline void finish_arch_post_lock_switch(void)
+{
+	struct mm_struct *mm = current->mm;
+
+	if (mm && mm->context.switch_pending) {
+		/*
+		 * Preemption must be disabled during cpu_switch_mm() as we
+		 * have some stateful cache flush implementations. Check
+		 * switch_pending again in case we were preempted and the
+		 * switch to this mm was already done.
+		 */
+		preempt_disable();
+		if (mm->context.switch_pending) {
+			mm->context.switch_pending = 0;
+			cpu_switch_mm(mm->pgd, mm);
+		}
+		preempt_enable_no_resched();
+	}
+}
+#endif /* !MODULE */
+
+#endif	/* CONFIG_MMU */
+
+static inline int
+init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+	return 0;
+}
+
+
+#endif	/* CONFIG_CPU_HAS_ASID */
+
+#define destroy_context(mm)		do { } while(0)
+#define activate_mm(prev,next)		switch_mm(prev, next, NULL)
+
+/*
+ * 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();
+
+	/*
+	 * __sync_icache_dcache doesn't broadcast the I-cache invalidation,
+	 * so check for possible thread migration and invalidate the I-cache
+	 * if we're new to this CPU.
+	 */
+	if (cache_ops_need_broadcast() &&
+	    !cpumask_empty(mm_cpumask(next)) &&
+	    !cpumask_test_cpu(cpu, mm_cpumask(next)))
+		__flush_icache_all();
+
+	if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
+		check_and_switch_context(next, tsk);
+		if (cache_is_vivt())
+			cpumask_clear_cpu(cpu, mm_cpumask(prev));
+	}
+#endif
+}
+
+#define deactivate_mm(tsk,mm)	do { } while (0)
+
+#endif