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