/* * linux/include/asm-arm/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 <asm/cacheflush.h> #include <asm/proc-fns.h> void __check_kvm_seq(struct mm_struct *mm); #if __LINUX_ARM_ARCH__ >= 6 /* * 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) extern unsigned int cpu_last_asid; 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) { 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) { if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq)) __check_kvm_seq(mm); } #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(); if (prev != next) { cpu_set(cpu, next->cpu_vm_mask); check_context(next); cpu_switch_mm(next->pgd, next); if (cache_is_vivt()) cpu_clear(cpu, prev->cpu_vm_mask); } #endif } #define deactivate_mm(tsk,mm) do { } while (0) #define activate_mm(prev,next) switch_mm(prev, next, NULL) #endif