1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * arch/arm/include/asm/mmu_context.h 4 * 5 * Copyright (C) 1996 Russell King. 6 * 7 * Changelog: 8 * 27-06-1996 RMK Created 9 */ 10 #ifndef __ASM_ARM_MMU_CONTEXT_H 11 #define __ASM_ARM_MMU_CONTEXT_H 12 13 #include <linux/compiler.h> 14 #include <linux/sched.h> 15 #include <linux/mm_types.h> 16 #include <linux/preempt.h> 17 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 #ifndef MODULE 70 #define finish_arch_post_lock_switch \ 71 finish_arch_post_lock_switch 72 static inline void finish_arch_post_lock_switch(void) 73 { 74 struct mm_struct *mm = current->mm; 75 76 if (mm && mm->context.switch_pending) { 77 /* 78 * Preemption must be disabled during cpu_switch_mm() as we 79 * have some stateful cache flush implementations. Check 80 * switch_pending again in case we were preempted and the 81 * switch to this mm was already done. 82 */ 83 preempt_disable(); 84 if (mm->context.switch_pending) { 85 mm->context.switch_pending = 0; 86 cpu_switch_mm(mm->pgd, mm); 87 } 88 preempt_enable_no_resched(); 89 } 90 } 91 #endif /* !MODULE */ 92 93 #endif /* CONFIG_MMU */ 94 95 static inline int 96 init_new_context(struct task_struct *tsk, struct mm_struct *mm) 97 { 98 return 0; 99 } 100 101 102 #endif /* CONFIG_CPU_HAS_ASID */ 103 104 #define destroy_context(mm) do { } while(0) 105 #define activate_mm(prev,next) switch_mm(prev, next, NULL) 106 107 /* 108 * This is called when "tsk" is about to enter lazy TLB mode. 109 * 110 * mm: describes the currently active mm context 111 * tsk: task which is entering lazy tlb 112 * cpu: cpu number which is entering lazy tlb 113 * 114 * tsk->mm will be NULL 115 */ 116 static inline void 117 enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) 118 { 119 } 120 121 /* 122 * This is the actual mm switch as far as the scheduler 123 * is concerned. No registers are touched. We avoid 124 * calling the CPU specific function when the mm hasn't 125 * actually changed. 126 */ 127 static inline void 128 switch_mm(struct mm_struct *prev, struct mm_struct *next, 129 struct task_struct *tsk) 130 { 131 #ifdef CONFIG_MMU 132 unsigned int cpu = smp_processor_id(); 133 134 /* 135 * __sync_icache_dcache doesn't broadcast the I-cache invalidation, 136 * so check for possible thread migration and invalidate the I-cache 137 * if we're new to this CPU. 138 */ 139 if (cache_ops_need_broadcast() && 140 !cpumask_empty(mm_cpumask(next)) && 141 !cpumask_test_cpu(cpu, mm_cpumask(next))) 142 __flush_icache_all(); 143 144 if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) { 145 check_and_switch_context(next, tsk); 146 if (cache_is_vivt()) 147 cpumask_clear_cpu(cpu, mm_cpumask(prev)); 148 } 149 #endif 150 } 151 152 #define deactivate_mm(tsk,mm) do { } while (0) 153 154 #endif 155