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