arch/s390/include/asm/mmu_context.h

   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.pgtable_lock);
  19         INIT_LIST_HEAD(&mm->context.pgtable_list);
  20         spin_lock_init(&mm->context.gmap_lock);
  21         INIT_LIST_HEAD(&mm->context.gmap_list);
  22         cpumask_clear(&mm->context.cpu_attach_mask);
  23         atomic_set(&mm->context.flush_count, 0);
  24         mm->context.gmap_asce = 0;
  25         mm->context.flush_mm = 0;
  26 #ifdef CONFIG_PGSTE
  27         mm->context.alloc_pgste = page_table_allocate_pgste;
  28         mm->context.has_pgste = 0;
  29         mm->context.use_skey = 0;
  30 #endif
  31         switch (mm->context.asce_limit) {
  32         case 1UL << 42:
  33                 /*
  34                  * forked 3-level task, fall through to set new asce with new
  35                  * mm->pgd
  36                  */
  37         case 0:
  38                 /* context created by exec, set asce limit to 4TB */
  39                 mm->context.asce_limit = STACK_TOP_MAX;
  40                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  41                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
  42                 break;
  43         case 1UL << 53:
  44                 /* forked 4-level task, set new asce with new mm->pgd */
  45                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  46                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
  47                 break;
  48         case 1UL << 31:
  49                 /* forked 2-level compat task, set new asce with new mm->pgd */
  50                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  51                                    _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
  52                 /* pgd_alloc() did not increase mm->nr_pmds */
  53                 mm_inc_nr_pmds(mm);
  54         }
  55         crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
  56         return 0;
  57 }
  58
  59 #define destroy_context(mm)             do { } while (0)
  60
  61 static inline void set_user_asce(struct mm_struct *mm)
  62 {
  63         S390_lowcore.user_asce = mm->context.asce;
  64         if (current->thread.mm_segment.ar4)
  65                 __ctl_load(S390_lowcore.user_asce, 7, 7);
  66         set_cpu_flag(CIF_ASCE);
  67 }
  68
  69 static inline void clear_user_asce(void)
  70 {
  71         S390_lowcore.user_asce = S390_lowcore.kernel_asce;
  72
  73         __ctl_load(S390_lowcore.user_asce, 1, 1);
  74         __ctl_load(S390_lowcore.user_asce, 7, 7);
  75 }
  76
  77 static inline void load_kernel_asce(void)
  78 {
  79         unsigned long asce;
  80
  81         __ctl_store(asce, 1, 1);
  82         if (asce != S390_lowcore.kernel_asce)
  83                 __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  84         set_cpu_flag(CIF_ASCE);
  85 }
  86
  87 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  88                              struct task_struct *tsk)
  89 {
  90         int cpu = smp_processor_id();
  91
  92         S390_lowcore.user_asce = next->context.asce;
  93         if (prev == next)
  94                 return;
  95         cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
  96         cpumask_set_cpu(cpu, mm_cpumask(next));
  97         /* Clear old ASCE by loading the kernel ASCE. */
  98         __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  99         __ctl_load(S390_lowcore.kernel_asce, 7, 7);
 100         cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
 101 }
 102
 103 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
 104 static inline void finish_arch_post_lock_switch(void)
 105 {
 106         struct task_struct *tsk = current;
 107         struct mm_struct *mm = tsk->mm;
 108
 109         load_kernel_asce();
 110         if (mm) {
 111                 preempt_disable();
 112                 while (atomic_read(&mm->context.flush_count))
 113                         cpu_relax();
 114
 115                 if (mm->context.flush_mm)
 116                         __tlb_flush_mm(mm);
 117                 preempt_enable();
 118         }
 119         set_fs(current->thread.mm_segment);
 120 }
 121
 122 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
 123 #define deactivate_mm(tsk,mm)   do { } while (0)
 124
 125 static inline void activate_mm(struct mm_struct *prev,
 126                                struct mm_struct *next)
 127 {
 128         switch_mm(prev, next, current);
 129         set_user_asce(next);
 130 }
 131
 132 static inline void arch_dup_mmap(struct mm_struct *oldmm,
 133                                  struct mm_struct *mm)
 134 {
 135 }
 136
 137 static inline void arch_exit_mmap(struct mm_struct *mm)
 138 {
 139 }
 140
 141 static inline void arch_unmap(struct mm_struct *mm,
 142                         struct vm_area_struct *vma,
 143                         unsigned long start, unsigned long end)
 144 {
 145 }
 146
 147 static inline void arch_bprm_mm_init(struct mm_struct *mm,
 148                                      struct vm_area_struct *vma)
 149 {
 150 }
 151
 152 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
 153                 bool write, bool execute, bool foreign)
 154 {
 155         /* by default, allow everything */
 156         return true;
 157 }
 158
 159 static inline bool arch_pte_access_permitted(pte_t pte, bool write)
 160 {
 161         /* by default, allow everything */
 162         return true;
 163 }
 164 #endif /* __S390_MMU_CONTEXT_H */