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