1 /* 2 * arch/arm/include/asm/mmu_context.h 3 * 4 * Copyright (C) 1996 Russell King. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * Changelog: 11 * 27-06-1996 RMK Created 12 */ 13 #ifndef __ASM_ARM_MMU_CONTEXT_H 14 #define __ASM_ARM_MMU_CONTEXT_H 15 16 #include <linux/compiler.h> 17 #include <linux/sched.h> 18 #include <asm/cacheflush.h> 19 #include <asm/cachetype.h> 20 #include <asm/proc-fns.h> 21 #include <asm-generic/mm_hooks.h> 22 23 void __check_vmalloc_seq(struct mm_struct *mm); 24 25 #ifdef CONFIG_CPU_HAS_ASID 26 27 void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk); 28 #define init_new_context(tsk,mm) ({ atomic64_set(&mm->context.id, 0); 0; }) 29 30 DECLARE_PER_CPU(atomic64_t, active_asids); 31 32 #else /* !CONFIG_CPU_HAS_ASID */ 33 34 #ifdef CONFIG_MMU 35 36 static inline void check_and_switch_context(struct mm_struct *mm, 37 struct task_struct *tsk) 38 { 39 if (unlikely(mm->context.vmalloc_seq != init_mm.context.vmalloc_seq)) 40 __check_vmalloc_seq(mm); 41 42 if (irqs_disabled()) 43 /* 44 * cpu_switch_mm() needs to flush the VIVT caches. To avoid 45 * high interrupt latencies, defer the call and continue 46 * running with the old mm. Since we only support UP systems 47 * on non-ASID CPUs, the old mm will remain valid until the 48 * finish_arch_post_lock_switch() call. 49 */ 50 set_ti_thread_flag(task_thread_info(tsk), TIF_SWITCH_MM); 51 else 52 cpu_switch_mm(mm->pgd, mm); 53 } 54 55 #define finish_arch_post_lock_switch \ 56 finish_arch_post_lock_switch 57 static inline void finish_arch_post_lock_switch(void) 58 { 59 if (test_and_clear_thread_flag(TIF_SWITCH_MM)) { 60 struct mm_struct *mm = current->mm; 61 cpu_switch_mm(mm->pgd, mm); 62 } 63 } 64 65 #endif /* CONFIG_MMU */ 66 67 #define init_new_context(tsk,mm) 0 68 69 #endif /* CONFIG_CPU_HAS_ASID */ 70 71 #define destroy_context(mm) do { } while(0) 72 #define activate_mm(prev,next) switch_mm(prev, next, NULL) 73 74 /* 75 * This is called when "tsk" is about to enter lazy TLB mode. 76 * 77 * mm: describes the currently active mm context 78 * tsk: task which is entering lazy tlb 79 * cpu: cpu number which is entering lazy tlb 80 * 81 * tsk->mm will be NULL 82 */ 83 static inline void 84 enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) 85 { 86 } 87 88 /* 89 * This is the actual mm switch as far as the scheduler 90 * is concerned. No registers are touched. We avoid 91 * calling the CPU specific function when the mm hasn't 92 * actually changed. 93 */ 94 static inline void 95 switch_mm(struct mm_struct *prev, struct mm_struct *next, 96 struct task_struct *tsk) 97 { 98 #ifdef CONFIG_MMU 99 unsigned int cpu = smp_processor_id(); 100 101 #ifdef CONFIG_SMP 102 /* check for possible thread migration */ 103 if (!cpumask_empty(mm_cpumask(next)) && 104 !cpumask_test_cpu(cpu, mm_cpumask(next))) 105 __flush_icache_all(); 106 #endif 107 if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) { 108 check_and_switch_context(next, tsk); 109 if (cache_is_vivt()) 110 cpumask_clear_cpu(cpu, mm_cpumask(prev)); 111 } 112 #endif 113 } 114 115 #define deactivate_mm(tsk,mm) do { } while (0) 116 117 #endif 118