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Diffstat (limited to 'arch/arm/include/asm/mmu_context.h')
-rw-r--r-- | arch/arm/include/asm/mmu_context.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/arch/arm/include/asm/mmu_context.h b/arch/arm/include/asm/mmu_context.h new file mode 100644 index 00000000..71605d9f --- /dev/null +++ b/arch/arm/include/asm/mmu_context.h @@ -0,0 +1,164 @@ +/* + * arch/arm/include/asm/mmu_context.h + * + * Copyright (C) 1996 Russell King. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Changelog: + * 27-06-1996 RMK Created + */ +#ifndef __ASM_ARM_MMU_CONTEXT_H +#define __ASM_ARM_MMU_CONTEXT_H + +#include <linux/compiler.h> +#include <linux/sched.h> +#include <asm/cacheflush.h> +#include <asm/cachetype.h> +#include <asm/proc-fns.h> + +void __check_kvm_seq(struct mm_struct *mm); + +#ifdef CONFIG_CPU_HAS_ASID + +/* + * On ARMv6, we have the following structure in the Context ID: + * + * 31 7 0 + * +-------------------------+-----------+ + * | process ID | ASID | + * +-------------------------+-----------+ + * | context ID | + * +-------------------------------------+ + * + * The ASID is used to tag entries in the CPU caches and TLBs. + * The context ID is used by debuggers and trace logic, and + * should be unique within all running processes. + */ +#define ASID_BITS 8 +#define ASID_MASK ((~0) << ASID_BITS) +#define ASID_FIRST_VERSION (1 << ASID_BITS) + +extern unsigned int cpu_last_asid; +#ifdef CONFIG_SMP +DECLARE_PER_CPU(struct mm_struct *, current_mm); +#endif + +void __init_new_context(struct task_struct *tsk, struct mm_struct *mm); +void __new_context(struct mm_struct *mm); + +static inline void check_context(struct mm_struct *mm) +{ + /* + * This code is executed with interrupts enabled. Therefore, + * mm->context.id cannot be updated to the latest ASID version + * on a different CPU (and condition below not triggered) + * without first getting an IPI to reset the context. The + * alternative is to take a read_lock on mm->context.id_lock + * (after changing its type to rwlock_t). + */ + if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS)) + __new_context(mm); + + if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq)) + __check_kvm_seq(mm); +} + +#define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0) + +#else + +static inline void check_context(struct mm_struct *mm) +{ +#ifdef CONFIG_MMU + if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq)) + __check_kvm_seq(mm); +#endif +} + +#define init_new_context(tsk,mm) 0 + +#endif + +#define destroy_context(mm) do { } while(0) + +/* + * This is called when "tsk" is about to enter lazy TLB mode. + * + * mm: describes the currently active mm context + * tsk: task which is entering lazy tlb + * cpu: cpu number which is entering lazy tlb + * + * tsk->mm will be NULL + */ +static inline void +enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) +{ +} + +/* + * This is the actual mm switch as far as the scheduler + * is concerned. No registers are touched. We avoid + * calling the CPU specific function when the mm hasn't + * actually changed. + */ +static inline void +switch_mm(struct mm_struct *prev, struct mm_struct *next, + struct task_struct *tsk) +{ +#ifdef CONFIG_MMU + unsigned int cpu = smp_processor_id(); + +#ifdef CONFIG_SMP + /* check for possible thread migration */ + if (!cpumask_empty(mm_cpumask(next)) && + !cpumask_test_cpu(cpu, mm_cpumask(next))) + __flush_icache_all(); +#endif + if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) { +#ifdef CONFIG_SMP + struct mm_struct **crt_mm = &per_cpu(current_mm, cpu); + *crt_mm = next; +#endif + check_context(next); + cpu_switch_mm(next->pgd, next); + if (cache_is_vivt()) + cpumask_clear_cpu(cpu, mm_cpumask(prev)); + } +#endif +} + +#define deactivate_mm(tsk,mm) do { } while (0) +#define activate_mm(prev,next) switch_mm(prev, next, NULL) + +/* + * We are inserting a "fake" vma for the user-accessible vector page so + * gdb and friends can get to it through ptrace and /proc/<pid>/mem. + * But we also want to remove it before the generic code gets to see it + * during process exit or the unmapping of it would cause total havoc. + * (the macro is used as remove_vma() is static to mm/mmap.c) + */ +#define arch_exit_mmap(mm) \ +do { \ + struct vm_area_struct *high_vma = find_vma(mm, 0xffff0000); \ + if (high_vma) { \ + BUG_ON(high_vma->vm_next); /* it should be last */ \ + if (high_vma->vm_prev) \ + high_vma->vm_prev->vm_next = NULL; \ + else \ + mm->mmap = NULL; \ + rb_erase(&high_vma->vm_rb, &mm->mm_rb); \ + mm->mmap_cache = NULL; \ + mm->map_count--; \ + remove_vma(high_vma); \ + } \ +} while (0) + +static inline void arch_dup_mmap(struct mm_struct *oldmm, + struct mm_struct *mm) +{ +} + +#endif |