Fixed MTP to work with TWRP

arch/mn10300/include/asm/mmu_context.h

@@ -0,0 +1,161 @@
+/* MN10300 MMU context management
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Modified by David Howells (dhowells@redhat.com)
+ * - Derived from include/asm-m32r/mmu_context.h
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ *
+ *
+ * This implements an algorithm to provide TLB PID mappings to provide
+ * selective access to the TLB for processes, thus reducing the number of TLB
+ * flushes required.
+ *
+ * Note, however, that the M32R algorithm is technically broken as it does not
+ * handle version wrap-around, and could, theoretically, have a problem with a
+ * very long lived program that sleeps long enough for the version number to
+ * wrap all the way around so that its TLB mappings appear valid once again.
+ */
+#ifndef _ASM_MMU_CONTEXT_H
+#define _ASM_MMU_CONTEXT_H
+
+#include <linux/atomic.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm-generic/mm_hooks.h>
+
+#define MMU_CONTEXT_TLBPID_NR		256
+#define MMU_CONTEXT_TLBPID_MASK		0x000000ffUL
+#define MMU_CONTEXT_VERSION_MASK	0xffffff00UL
+#define MMU_CONTEXT_FIRST_VERSION	0x00000100UL
+#define MMU_NO_CONTEXT			0x00000000UL
+#define MMU_CONTEXT_TLBPID_LOCK_NR	0
+
+#define enter_lazy_tlb(mm, tsk)	do {} while (0)
+
+static inline void cpu_ran_vm(int cpu, struct mm_struct *mm)
+{
+#ifdef CONFIG_SMP
+	cpumask_set_cpu(cpu, mm_cpumask(mm));
+#endif
+}
+
+static inline bool cpu_maybe_ran_vm(int cpu, struct mm_struct *mm)
+{
+#ifdef CONFIG_SMP
+	return cpumask_test_and_set_cpu(cpu, mm_cpumask(mm));
+#else
+	return true;
+#endif
+}
+
+#ifdef CONFIG_MN10300_TLB_USE_PIDR
+extern unsigned long mmu_context_cache[NR_CPUS];
+#define mm_context(mm)	(mm->context.tlbpid[smp_processor_id()])
+
+/**
+ * allocate_mmu_context - Allocate storage for the arch-specific MMU data
+ * @mm: The userspace VM context being set up
+ */
+static inline unsigned long allocate_mmu_context(struct mm_struct *mm)
+{
+	unsigned long *pmc = &mmu_context_cache[smp_processor_id()];
+	unsigned long mc = ++(*pmc);
+
+	if (!(mc & MMU_CONTEXT_TLBPID_MASK)) {
+		/* we exhausted the TLB PIDs of this version on this CPU, so we
+		 * flush this CPU's TLB in its entirety and start new cycle */
+		local_flush_tlb_all();
+
+		/* fix the TLB version if needed (we avoid version #0 so as to
+		 * distinguish MMU_NO_CONTEXT) */
+		if (!mc)
+			*pmc = mc = MMU_CONTEXT_FIRST_VERSION;
+	}
+	mm_context(mm) = mc;
+	return mc;
+}
+
+/*
+ * get an MMU context if one is needed
+ */
+static inline unsigned long get_mmu_context(struct mm_struct *mm)
+{
+	unsigned long mc = MMU_NO_CONTEXT, cache;
+
+	if (mm) {
+		cache = mmu_context_cache[smp_processor_id()];
+		mc = mm_context(mm);
+
+		/* if we have an old version of the context, replace it */
+		if ((mc ^ cache) & MMU_CONTEXT_VERSION_MASK)
+			mc = allocate_mmu_context(mm);
+	}
+	return mc;
+}
+
+/*
+ * initialise the context related info for a new mm_struct instance
+ */
+static inline int init_new_context(struct task_struct *tsk,
+				   struct mm_struct *mm)
+{
+	int num_cpus = NR_CPUS, i;
+
+	for (i = 0; i < num_cpus; i++)
+		mm->context.tlbpid[i] = MMU_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_context(struct mm_struct *mm)
+{
+	PIDR = get_mmu_context(mm) & MMU_CONTEXT_TLBPID_MASK;
+}
+#else  /* CONFIG_MN10300_TLB_USE_PIDR */
+
+#define init_new_context(tsk, mm)	(0)
+#define activate_context(mm)		local_flush_tlb()
+
+#endif /* CONFIG_MN10300_TLB_USE_PIDR */
+
+/**
+ * destroy_context - Destroy mm context information
+ * @mm: The MM being destroyed.
+ *
+ * Destroy context related info for an mm_struct that is about to be put to
+ * rest
+ */
+#define destroy_context(mm)	do {} while (0)
+
+/**
+ * switch_mm - Change between userspace virtual memory contexts
+ * @prev: The outgoing MM context.
+ * @next: The incoming MM context.
+ * @tsk: The incoming task.
+ */
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+			     struct task_struct *tsk)
+{
+	int cpu = smp_processor_id();
+
+	if (prev != next) {
+#ifdef CONFIG_SMP
+		per_cpu(cpu_tlbstate, cpu).active_mm = next;
+#endif
+		cpu_ran_vm(cpu, next);
+		PTBR = (unsigned long) next->pgd;
+		activate_context(next);
+	}
+}
+
+#define deactivate_mm(tsk, mm)	do {} while (0)
+#define activate_mm(prev, next)	switch_mm((prev), (next), NULL)
+
+#endif /* _ASM_MMU_CONTEXT_H */