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 <linux/uaccess.h>
  12 #include <linux/mm_types.h>
  13 #include <asm/tlbflush.h>
  14 #include <asm/ctl_reg.h>
  15
  16 static inline int init_new_context(struct task_struct *tsk,
  17                                    struct mm_struct *mm)
  18 {
  19         spin_lock_init(&mm->context.pgtable_lock);
  20         INIT_LIST_HEAD(&mm->context.pgtable_list);
  21         spin_lock_init(&mm->context.gmap_lock);
  22         INIT_LIST_HEAD(&mm->context.gmap_list);
  23         cpumask_clear(&mm->context.cpu_attach_mask);
  24         atomic_set(&mm->context.flush_count, 0);
  25         mm->context.gmap_asce = 0;
  26         mm->context.flush_mm = 0;
  27 #ifdef CONFIG_PGSTE
  28         mm->context.alloc_pgste = page_table_allocate_pgste ||
  29                 test_thread_flag(TIF_PGSTE) ||
  30                 current->mm->context.alloc_pgste;
  31         mm->context.has_pgste = 0;
  32         mm->context.use_skey = 0;
  33         mm->context.use_cmma = 0;
  34 #endif
  35         switch (mm->context.asce_limit) {
  36         case 1UL << 42:
  37                 /*
  38                  * forked 3-level task, fall through to set new asce with new
  39                  * mm->pgd
  40                  */
  41         case 0:
  42                 /* context created by exec, set asce limit to 4TB */
  43                 mm->context.asce_limit = STACK_TOP_MAX;
  44                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  45                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
  46                 break;
  47         case -PAGE_SIZE:
  48                 /* forked 5-level task, set new asce with new_mm->pgd */
  49                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  50                         _ASCE_USER_BITS | _ASCE_TYPE_REGION1;
  51                 break;
  52         case 1UL << 53:
  53                 /* forked 4-level task, set new asce with new mm->pgd */
  54                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  55                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
  56                 break;
  57         case 1UL << 31:
  58                 /* forked 2-level compat task, set new asce with new mm->pgd */
  59                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  60                                    _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
  61                 /* pgd_alloc() did not increase mm->nr_pmds */
  62                 mm_inc_nr_pmds(mm);
  63         }
  64         crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
  65         return 0;
  66 }
  67
  68 #define destroy_context(mm)             do { } while (0)
  69
  70 static inline void set_user_asce(struct mm_struct *mm)
  71 {
  72         S390_lowcore.user_asce = mm->context.asce;
  73         if (current->thread.mm_segment.ar4)
  74                 __ctl_load(S390_lowcore.user_asce, 7, 7);
  75         set_cpu_flag(CIF_ASCE_PRIMARY);
  76 }
  77
  78 static inline void clear_user_asce(void)
  79 {
  80         S390_lowcore.user_asce = S390_lowcore.kernel_asce;
  81
  82         __ctl_load(S390_lowcore.user_asce, 1, 1);
  83         __ctl_load(S390_lowcore.user_asce, 7, 7);
  84 }
  85
  86 static inline void load_kernel_asce(void)
  87 {
  88         unsigned long asce;
  89
  90         __ctl_store(asce, 1, 1);
  91         if (asce != S390_lowcore.kernel_asce)
  92                 __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  93         set_cpu_flag(CIF_ASCE_PRIMARY);
  94 }
  95
  96 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  97                              struct task_struct *tsk)
  98 {
  99         int cpu = smp_processor_id();
 100
 101         S390_lowcore.user_asce = next->context.asce;
 102         if (prev == next)
 103                 return;
 104         cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
 105         cpumask_set_cpu(cpu, mm_cpumask(next));
 106         /* Clear old ASCE by loading the kernel ASCE. */
 107         __ctl_load(S390_lowcore.kernel_asce, 1, 1);
 108         __ctl_load(S390_lowcore.kernel_asce, 7, 7);
 109         cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
 110 }
 111
 112 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
 113 static inline void finish_arch_post_lock_switch(void)
 114 {
 115         struct task_struct *tsk = current;
 116         struct mm_struct *mm = tsk->mm;
 117
 118         load_kernel_asce();
 119         if (mm) {
 120                 preempt_disable();
 121                 while (atomic_read(&mm->context.flush_count))
 122                         cpu_relax();
 123
 124                 if (mm->context.flush_mm)
 125                         __tlb_flush_mm(mm);
 126                 preempt_enable();
 127         }
 128         set_fs(current->thread.mm_segment);
 129 }
 130
 131 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
 132 #define deactivate_mm(tsk,mm)   do { } while (0)
 133
 134 static inline void activate_mm(struct mm_struct *prev,
 135                                struct mm_struct *next)
 136 {
 137         switch_mm(prev, next, current);
 138         set_user_asce(next);
 139 }
 140
 141 static inline void arch_dup_mmap(struct mm_struct *oldmm,
 142                                  struct mm_struct *mm)
 143 {
 144 }
 145
 146 static inline void arch_exit_mmap(struct mm_struct *mm)
 147 {
 148 }
 149
 150 static inline void arch_unmap(struct mm_struct *mm,
 151                         struct vm_area_struct *vma,
 152                         unsigned long start, unsigned long end)
 153 {
 154 }
 155
 156 static inline void arch_bprm_mm_init(struct mm_struct *mm,
 157                                      struct vm_area_struct *vma)
 158 {
 159 }
 160
 161 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
 162                 bool write, bool execute, bool foreign)
 163 {
 164         /* by default, allow everything */
 165         return true;
 166 }
 167 #endif /* __S390_MMU_CONTEXT_H */