1 files changed, 237 insertions, 0 deletions
diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h
new file mode 100644
index 000000000..ed9f2d748
--- /dev/null
+++ b/arch/mips/include/asm/mmu_context.h
@@ -0,0 +1,237 @@
+/*
+ * Switch a 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) 1996, 1997, 1998, 1999 by Ralf Baechle
+ * Copyright (C) 1999 Silicon Graphics, Inc.
+ */
+#ifndef _ASM_MMU_CONTEXT_H
+#define _ASM_MMU_CONTEXT_H
+
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/mm_types.h>
+#include <linux/smp.h>
+#include <linux/slab.h>
+
+#include <asm/barrier.h>
+#include <asm/cacheflush.h>
+#include <asm/dsemul.h>
+#include <asm/ginvt.h>
+#include <asm/hazards.h>
+#include <asm/tlbflush.h>
+#include <asm-generic/mm_hooks.h>
+
+#define htw_set_pwbase(pgd)						\
+do {									\
+	if (cpu_has_htw) {						\
+		write_c0_pwbase(pgd);					\
+		back_to_back_c0_hazard();				\
+	}								\
+} while (0)
+
+extern void tlbmiss_handler_setup_pgd(unsigned long);
+extern char tlbmiss_handler_setup_pgd_end[];
+
+/* Note: This is also implemented with uasm in arch/mips/kvm/entry.c */
+#define TLBMISS_HANDLER_SETUP_PGD(pgd)					\
+do {									\
+	tlbmiss_handler_setup_pgd((unsigned long)(pgd));		\
+	htw_set_pwbase((unsigned long)pgd);				\
+} while (0)
+
+#ifdef CONFIG_MIPS_PGD_C0_CONTEXT
+
+#define TLBMISS_HANDLER_RESTORE()					\
+	write_c0_xcontext((unsigned long) smp_processor_id() <<		\
+			  SMP_CPUID_REGSHIFT)
+
+#define TLBMISS_HANDLER_SETUP()						\
+	do {								\
+		TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir);		\
+		TLBMISS_HANDLER_RESTORE();				\
+	} while (0)
+
+#else /* !CONFIG_MIPS_PGD_C0_CONTEXT: using  pgd_current*/
+
+/*
+ * For the fast tlb miss handlers, we keep a per cpu array of pointers
+ * to the current pgd for each processor. Also, the proc. id is stuffed
+ * into the context register.
+ */
+extern unsigned long pgd_current[];
+
+#define TLBMISS_HANDLER_RESTORE()					\
+	write_c0_context((unsigned long) smp_processor_id() <<		\
+			 SMP_CPUID_REGSHIFT)
+
+#define TLBMISS_HANDLER_SETUP()						\
+	TLBMISS_HANDLER_RESTORE();					\
+	back_to_back_c0_hazard();					\
+	TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
+#endif /* CONFIG_MIPS_PGD_C0_CONTEXT*/
+
+/*
+ * The ginvt instruction will invalidate wired entries when its type field
+ * targets anything other than the entire TLB. That means that if we were to
+ * allow the kernel to create wired entries with the MMID of current->active_mm
+ * then those wired entries could be invalidated when we later use ginvt to
+ * invalidate TLB entries with that MMID.
+ *
+ * In order to prevent ginvt from trashing wired entries, we reserve one MMID
+ * for use by the kernel when creating wired entries. This MMID will never be
+ * assigned to a struct mm, and we'll never target it with a ginvt instruction.
+ */
+#define MMID_KERNEL_WIRED	0
+
+/*
+ *  All unused by hardware upper bits will be considered
+ *  as a software asid extension.
+ */
+static inline u64 asid_version_mask(unsigned int cpu)
+{
+	unsigned long asid_mask = cpu_asid_mask(&cpu_data[cpu]);
+
+	return ~(u64)(asid_mask | (asid_mask - 1));
+}
+
+static inline u64 asid_first_version(unsigned int cpu)
+{
+	return ~asid_version_mask(cpu) + 1;
+}
+
+static inline u64 cpu_context(unsigned int cpu, const struct mm_struct *mm)
+{
+	if (cpu_has_mmid)
+		return atomic64_read(&mm->context.mmid);
+
+	return mm->context.asid[cpu];
+}
+
+static inline void set_cpu_context(unsigned int cpu,
+				   struct mm_struct *mm, u64 ctx)
+{
+	if (cpu_has_mmid)
+		atomic64_set(&mm->context.mmid, ctx);
+	else
+		mm->context.asid[cpu] = ctx;
+}
+
+#define asid_cache(cpu)		(cpu_data[cpu].asid_cache)
+#define cpu_asid(cpu, mm) \
+	(cpu_context((cpu), (mm)) & cpu_asid_mask(&cpu_data[cpu]))
+
+extern void get_new_mmu_context(struct mm_struct *mm);
+extern void check_mmu_context(struct mm_struct *mm);
+extern void check_switch_mmu_context(struct mm_struct *mm);
+
+/*
+ * Initialize the context related info for a new mm_struct
+ * instance.
+ */
+#define init_new_context init_new_context
+static inline int
+init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+	int i;
+
+	if (cpu_has_mmid) {
+		set_cpu_context(0, mm, 0);
+	} else {
+		for_each_possible_cpu(i)
+			set_cpu_context(i, mm, 0);
+	}
+
+	mm->context.bd_emupage_allocmap = NULL;
+	spin_lock_init(&mm->context.bd_emupage_lock);
+	init_waitqueue_head(&mm->context.bd_emupage_queue);
+
+	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();
+	unsigned long flags;
+	local_irq_save(flags);
+
+	htw_stop();
+	check_switch_mmu_context(next);
+
+	/*
+	 * Mark current->active_mm as not "active" anymore.
+	 * We don't want to mislead possible IPI tlb flush routines.
+	 */
+	cpumask_clear_cpu(cpu, mm_cpumask(prev));
+	cpumask_set_cpu(cpu, mm_cpumask(next));
+	htw_start();
+
+	local_irq_restore(flags);
+}
+
+/*
+ * Destroy context related info for an mm_struct that is about
+ * to be put to rest.
+ */
+#define destroy_context destroy_context
+static inline void destroy_context(struct mm_struct *mm)
+{
+	dsemul_mm_cleanup(mm);
+}
+
+static inline void
+drop_mmu_context(struct mm_struct *mm)
+{
+	unsigned long flags;
+	unsigned int cpu;
+	u32 old_mmid;
+	u64 ctx;
+
+	local_irq_save(flags);
+
+	cpu = smp_processor_id();
+	ctx = cpu_context(cpu, mm);
+
+	if (!ctx) {
+		/* no-op */
+	} else if (cpu_has_mmid) {
+		/*
+		 * Globally invalidating TLB entries associated with the MMID
+		 * is pretty cheap using the GINVT instruction, so we'll do
+		 * that rather than incur the overhead of allocating a new
+		 * MMID. The latter would be especially difficult since MMIDs
+		 * are global & other CPUs may be actively using ctx.
+		 */
+		htw_stop();
+		old_mmid = read_c0_memorymapid();
+		write_c0_memorymapid(ctx & cpu_asid_mask(&cpu_data[cpu]));
+		mtc0_tlbw_hazard();
+		ginvt_mmid();
+		sync_ginv();
+		write_c0_memorymapid(old_mmid);
+		instruction_hazard();
+		htw_start();
+	} else if (cpumask_test_cpu(cpu, mm_cpumask(mm))) {
+		/*
+		 * mm is currently active, so we can't really drop it.
+		 * Instead we bump the ASID.
+		 */
+		htw_stop();
+		get_new_mmu_context(mm);
+		write_c0_entryhi(cpu_asid(cpu, mm));
+		htw_start();
+	} else {
+		/* will get a new context next time */
+		set_cpu_context(cpu, mm, 0);
+	}
+
+	local_irq_restore(flags);
+}
+
+#include <asm-generic/mmu_context.h>
+
+#endif /* _ASM_MMU_CONTEXT_H */