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 <linux/mm_types.h> 19 #include <linux/preempt.h> 20 21 #include <asm/cacheflush.h> 22 #include <asm/cachetype.h> 23 #include <asm/proc-fns.h> 24 #include <asm/smp_plat.h> 25 #include <asm-generic/mm_hooks.h> 26 27 void __check_vmalloc_seq(struct mm_struct *mm); 28 29 #ifdef CONFIG_CPU_HAS_ASID 30 31 void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk); 32 static inline int 33 init_new_context(struct task_struct *tsk, struct mm_struct *mm) 34 { 35 atomic64_set(&mm->context.id, 0); 36 return 0; 37 } 38 39 #ifdef CONFIG_ARM_ERRATA_798181 40 void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm, 41 cpumask_t *mask); 42 #else /* !CONFIG_ARM_ERRATA_798181 */ 43 static inline void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm, 44 cpumask_t *mask) 45 { 46 } 47 #endif /* CONFIG_ARM_ERRATA_798181 */ 48 49 #else /* !CONFIG_CPU_HAS_ASID */ 50 51 #ifdef CONFIG_MMU 52 53 static inline void check_and_switch_context(struct mm_struct *mm, 54 struct task_struct *tsk) 55 { 56 if (unlikely(mm->context.vmalloc_seq != init_mm.context.vmalloc_seq)) 57 __check_vmalloc_seq(mm); 58 59 if (irqs_disabled()) 60 /* 61 * cpu_switch_mm() needs to flush the VIVT caches. To avoid 62 * high interrupt latencies, defer the call and continue 63 * running with the old mm. Since we only support UP systems 64 * on non-ASID CPUs, the old mm will remain valid until the 65 * finish_arch_post_lock_switch() call. 66 */ 67 mm->context.switch_pending = 1; 68 else 69 cpu_switch_mm(mm->pgd, mm); 70 } 71 72 #ifndef MODULE 73 #define finish_arch_post_lock_switch \ 74 finish_arch_post_lock_switch 75 static inline void finish_arch_post_lock_switch(void) 76 { 77 struct mm_struct *mm = current->mm; 78 79 if (mm && mm->context.switch_pending) { 80 /* 81 * Preemption must be disabled during cpu_switch_mm() as we 82 * have some stateful cache flush implementations. Check 83 * switch_pending again in case we were preempted and the 84 * switch to this mm was already done. 85 */ 86 preempt_disable(); 87 if (mm->context.switch_pending) { 88 mm->context.switch_pending = 0; 89 cpu_switch_mm(mm->pgd, mm); 90 } 91 preempt_enable_no_resched(); 92 } 93 } 94 #endif /* !MODULE */ 95 96 #endif /* CONFIG_MMU */ 97 98 static inline int 99 init_new_context(struct task_struct *tsk, struct mm_struct *mm) 100 { 101 return 0; 102 } 103 104 105 #endif /* CONFIG_CPU_HAS_ASID */ 106 107 #define destroy_context(mm) do { } while(0) 108 #define activate_mm(prev,next) switch_mm(prev, next, NULL) 109 110 /* 111 * This is called when "tsk" is about to enter lazy TLB mode. 112 * 113 * mm: describes the currently active mm context 114 * tsk: task which is entering lazy tlb 115 * cpu: cpu number which is entering lazy tlb 116 * 117 * tsk->mm will be NULL 118 */ 119 static inline void 120 enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) 121 { 122 } 123 124 /* 125 * This is the actual mm switch as far as the scheduler 126 * is concerned. No registers are touched. We avoid 127 * calling the CPU specific function when the mm hasn't 128 * actually changed. 129 */ 130 static inline void 131 switch_mm(struct mm_struct *prev, struct mm_struct *next, 132 struct task_struct *tsk) 133 { 134 #ifdef CONFIG_MMU 135 unsigned int cpu = smp_processor_id(); 136 137 /* 138 * __sync_icache_dcache doesn't broadcast the I-cache invalidation, 139 * so check for possible thread migration and invalidate the I-cache 140 * if we're new to this CPU. 141 */ 142 if (cache_ops_need_broadcast() && 143 !cpumask_empty(mm_cpumask(next)) && 144 !cpumask_test_cpu(cpu, mm_cpumask(next))) 145 __flush_icache_all(); 146 147 if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) { 148 check_and_switch_context(next, tsk); 149 if (cache_is_vivt()) 150 cpumask_clear_cpu(cpu, mm_cpumask(prev)); 151 } 152 #endif 153 } 154 155 #define deactivate_mm(tsk,mm) do { } while (0) 156 157 #endif 158