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