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.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 */