1 /* 2 * S390 version 3 * 4 * Derived from "include/asm-i386/mmu_context.h" 5 */ 6 7 #ifndef __S390_MMU_CONTEXT_H 8 #define __S390_MMU_CONTEXT_H 9 10 #include <asm/pgalloc.h> 11 #include <asm/uaccess.h> 12 #include <asm/tlbflush.h> 13 #include <asm/ctl_reg.h> 14 15 static inline int init_new_context(struct task_struct *tsk, 16 struct mm_struct *mm) 17 { 18 spin_lock_init(&mm->context.list_lock); 19 INIT_LIST_HEAD(&mm->context.pgtable_list); 20 INIT_LIST_HEAD(&mm->context.gmap_list); 21 cpumask_clear(&mm->context.cpu_attach_mask); 22 atomic_set(&mm->context.attach_count, 0); 23 mm->context.flush_mm = 0; 24 #ifdef CONFIG_PGSTE 25 mm->context.alloc_pgste = page_table_allocate_pgste; 26 mm->context.has_pgste = 0; 27 mm->context.use_skey = 0; 28 #endif 29 if (mm->context.asce_limit == 0) { 30 /* context created by exec, set asce limit to 4TB */ 31 mm->context.asce_bits = _ASCE_TABLE_LENGTH | 32 _ASCE_USER_BITS | _ASCE_TYPE_REGION3; 33 mm->context.asce_limit = STACK_TOP_MAX; 34 } else if (mm->context.asce_limit == (1UL << 31)) { 35 mm_inc_nr_pmds(mm); 36 } 37 crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm)); 38 return 0; 39 } 40 41 #define destroy_context(mm) do { } while (0) 42 43 static inline void set_user_asce(struct mm_struct *mm) 44 { 45 S390_lowcore.user_asce = mm->context.asce_bits | __pa(mm->pgd); 46 if (current->thread.mm_segment.ar4) 47 __ctl_load(S390_lowcore.user_asce, 7, 7); 48 set_cpu_flag(CIF_ASCE); 49 } 50 51 static inline void clear_user_asce(void) 52 { 53 S390_lowcore.user_asce = S390_lowcore.kernel_asce; 54 55 __ctl_load(S390_lowcore.user_asce, 1, 1); 56 __ctl_load(S390_lowcore.user_asce, 7, 7); 57 } 58 59 static inline void load_kernel_asce(void) 60 { 61 unsigned long asce; 62 63 __ctl_store(asce, 1, 1); 64 if (asce != S390_lowcore.kernel_asce) 65 __ctl_load(S390_lowcore.kernel_asce, 1, 1); 66 set_cpu_flag(CIF_ASCE); 67 } 68 69 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, 70 struct task_struct *tsk) 71 { 72 int cpu = smp_processor_id(); 73 74 S390_lowcore.user_asce = next->context.asce_bits | __pa(next->pgd); 75 if (prev == next) 76 return; 77 if (MACHINE_HAS_TLB_LC) 78 cpumask_set_cpu(cpu, &next->context.cpu_attach_mask); 79 /* Clear old ASCE by loading the kernel ASCE. */ 80 __ctl_load(S390_lowcore.kernel_asce, 1, 1); 81 __ctl_load(S390_lowcore.kernel_asce, 7, 7); 82 atomic_inc(&next->context.attach_count); 83 atomic_dec(&prev->context.attach_count); 84 if (MACHINE_HAS_TLB_LC) 85 cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask); 86 } 87 88 #define finish_arch_post_lock_switch finish_arch_post_lock_switch 89 static inline void finish_arch_post_lock_switch(void) 90 { 91 struct task_struct *tsk = current; 92 struct mm_struct *mm = tsk->mm; 93 94 load_kernel_asce(); 95 if (mm) { 96 preempt_disable(); 97 while (atomic_read(&mm->context.attach_count) >> 16) 98 cpu_relax(); 99 100 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm)); 101 if (mm->context.flush_mm) 102 __tlb_flush_mm(mm); 103 preempt_enable(); 104 } 105 set_fs(current->thread.mm_segment); 106 } 107 108 #define enter_lazy_tlb(mm,tsk) do { } while (0) 109 #define deactivate_mm(tsk,mm) do { } while (0) 110 111 static inline void activate_mm(struct mm_struct *prev, 112 struct mm_struct *next) 113 { 114 switch_mm(prev, next, current); 115 cpumask_set_cpu(smp_processor_id(), mm_cpumask(next)); 116 set_user_asce(next); 117 } 118 119 static inline void arch_dup_mmap(struct mm_struct *oldmm, 120 struct mm_struct *mm) 121 { 122 } 123 124 static inline void arch_exit_mmap(struct mm_struct *mm) 125 { 126 } 127 128 static inline void arch_unmap(struct mm_struct *mm, 129 struct vm_area_struct *vma, 130 unsigned long start, unsigned long end) 131 { 132 } 133 134 static inline void arch_bprm_mm_init(struct mm_struct *mm, 135 struct vm_area_struct *vma) 136 { 137 } 138 139 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, 140 bool write, bool execute, bool foreign) 141 { 142 /* by default, allow everything */ 143 return true; 144 } 145 146 static inline bool arch_pte_access_permitted(pte_t pte, bool write) 147 { 148 /* by default, allow everything */ 149 return true; 150 } 151 #endif /* __S390_MMU_CONTEXT_H */ 152