165 строки
4.4 KiB
C
165 строки
4.4 KiB
C
/*
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* arch/arm/include/asm/mmu_context.h
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*
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* Copyright (C) 1996 Russell King.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Changelog:
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* 27-06-1996 RMK Created
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*/
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#ifndef __ASM_ARM_MMU_CONTEXT_H
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#define __ASM_ARM_MMU_CONTEXT_H
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#include <linux/compiler.h>
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#include <linux/sched.h>
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#include <asm/cacheflush.h>
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#include <asm/cachetype.h>
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#include <asm/proc-fns.h>
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void __check_kvm_seq(struct mm_struct *mm);
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#ifdef CONFIG_CPU_HAS_ASID
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/*
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* On ARMv6, we have the following structure in the Context ID:
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*
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* 31 7 0
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* +-------------------------+-----------+
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* | process ID | ASID |
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* +-------------------------+-----------+
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* | context ID |
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* +-------------------------------------+
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*
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* The ASID is used to tag entries in the CPU caches and TLBs.
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* The context ID is used by debuggers and trace logic, and
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* should be unique within all running processes.
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*/
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#define ASID_BITS 8
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#define ASID_MASK ((~0) << ASID_BITS)
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#define ASID_FIRST_VERSION (1 << ASID_BITS)
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extern unsigned int cpu_last_asid;
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#ifdef CONFIG_SMP
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DECLARE_PER_CPU(struct mm_struct *, current_mm);
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#endif
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void __init_new_context(struct task_struct *tsk, struct mm_struct *mm);
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void __new_context(struct mm_struct *mm);
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static inline void check_context(struct mm_struct *mm)
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{
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/*
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* This code is executed with interrupts enabled. Therefore,
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* mm->context.id cannot be updated to the latest ASID version
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* on a different CPU (and condition below not triggered)
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* without first getting an IPI to reset the context. The
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* alternative is to take a read_lock on mm->context.id_lock
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* (after changing its type to rwlock_t).
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*/
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if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS))
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__new_context(mm);
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if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
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__check_kvm_seq(mm);
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}
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#define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0)
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#else
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static inline void check_context(struct mm_struct *mm)
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{
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#ifdef CONFIG_MMU
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if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
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__check_kvm_seq(mm);
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#endif
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}
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#define init_new_context(tsk,mm) 0
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#endif
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#define destroy_context(mm) do { } while(0)
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/*
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* This is called when "tsk" is about to enter lazy TLB mode.
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*
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* mm: describes the currently active mm context
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* tsk: task which is entering lazy tlb
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* cpu: cpu number which is entering lazy tlb
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*
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* tsk->mm will be NULL
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*/
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static inline void
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enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
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{
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}
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/*
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* This is the actual mm switch as far as the scheduler
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* is concerned. No registers are touched. We avoid
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* calling the CPU specific function when the mm hasn't
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* actually changed.
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*/
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static inline void
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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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#ifdef CONFIG_MMU
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unsigned int cpu = smp_processor_id();
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#ifdef CONFIG_SMP
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/* check for possible thread migration */
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if (!cpumask_empty(mm_cpumask(next)) &&
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!cpumask_test_cpu(cpu, mm_cpumask(next)))
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__flush_icache_all();
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#endif
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if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
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#ifdef CONFIG_SMP
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struct mm_struct **crt_mm = &per_cpu(current_mm, cpu);
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*crt_mm = next;
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#endif
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check_context(next);
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cpu_switch_mm(next->pgd, next);
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if (cache_is_vivt())
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cpumask_clear_cpu(cpu, mm_cpumask(prev));
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}
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#endif
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}
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#define deactivate_mm(tsk,mm) do { } while (0)
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#define activate_mm(prev,next) switch_mm(prev, next, NULL)
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/*
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* We are inserting a "fake" vma for the user-accessible vector page so
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* gdb and friends can get to it through ptrace and /proc/<pid>/mem.
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* But we also want to remove it before the generic code gets to see it
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* during process exit or the unmapping of it would cause total havoc.
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* (the macro is used as remove_vma() is static to mm/mmap.c)
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*/
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#define arch_exit_mmap(mm) \
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do { \
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struct vm_area_struct *high_vma = find_vma(mm, 0xffff0000); \
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if (high_vma) { \
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BUG_ON(high_vma->vm_next); /* it should be last */ \
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if (high_vma->vm_prev) \
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high_vma->vm_prev->vm_next = NULL; \
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else \
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mm->mmap = NULL; \
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rb_erase(&high_vma->vm_rb, &mm->mm_rb); \
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mm->mmap_cache = NULL; \
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mm->map_count--; \
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remove_vma(high_vma); \
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} \
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} while (0)
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static inline void arch_dup_mmap(struct mm_struct *oldmm,
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struct mm_struct *mm)
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{
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}
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#endif
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