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