ff0daca525
Allow section mappings to be setup using ioremap() and torn down with iounmap(). This requires additional support in the MM context switch to ensure that mappings are properly synchronised when mapped in. Based an original implementation by Deepak Saxena, reworked and ARMv6 support added by rmk. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
112 lines
2.7 KiB
C
112 lines
2.7 KiB
C
/*
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* linux/include/asm-arm/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 <asm/cacheflush.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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#if __LINUX_ARM_ARCH__ >= 6
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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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extern unsigned int cpu_last_asid;
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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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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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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) 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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if (prev != next) {
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cpu_set(cpu, next->cpu_vm_mask);
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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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cpu_clear(cpu, prev->cpu_vm_mask);
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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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#endif
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