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