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 #include <asm-generic/mm_hooks.h>
  16
  17 static inline int init_new_context(struct task_struct *tsk,
  18                                    struct mm_struct *mm)
  19 {
  20         spin_lock_init(&mm->context.pgtable_lock);
  21         INIT_LIST_HEAD(&mm->context.pgtable_list);
  22         spin_lock_init(&mm->context.gmap_lock);
  23         INIT_LIST_HEAD(&mm->context.gmap_list);
  24         cpumask_clear(&mm->context.cpu_attach_mask);
  25         atomic_set(&mm->context.flush_count, 0);
  26         mm->context.gmap_asce = 0;
  27         mm->context.flush_mm = 0;
  28 #ifdef CONFIG_PGSTE
  29         mm->context.alloc_pgste = page_table_allocate_pgste ||
  30                 test_thread_flag(TIF_PGSTE) ||
  31                 current->mm->context.alloc_pgste;
  32         mm->context.has_pgste = 0;
  33         mm->context.use_skey = 0;
  34         mm->context.use_cmma = 0;
  35 #endif
  36         switch (mm->context.asce_limit) {
  37         case _REGION2_SIZE:
  38                 /*
  39                  * forked 3-level task, fall through to set new asce with new
  40                  * mm->pgd
  41                  */
  42         case 0:
  43                 /* context created by exec, set asce limit to 4TB */
  44                 mm->context.asce_limit = STACK_TOP_MAX;
  45                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  46                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
  47                 break;
  48         case _REGION1_SIZE:
  49                 /* forked 4-level task, set new asce with new mm->pgd */
  50                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  51                                    _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
  52                 break;
  53         case _REGION3_SIZE:
  54                 /* forked 2-level compat task, set new asce with new mm->pgd */
  55                 mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
  56                                    _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
  57                 /* pgd_alloc() did not increase mm->nr_pmds */
  58                 mm_inc_nr_pmds(mm);
  59         }
  60         crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
  61         return 0;
  62 }
  63
  64 #define destroy_context(mm)             do { } while (0)
  65
  66 static inline void set_user_asce(struct mm_struct *mm)
  67 {
  68         S390_lowcore.user_asce = mm->context.asce;
  69         if (current->thread.mm_segment.ar4)
  70                 __ctl_load(S390_lowcore.user_asce, 7, 7);
  71         set_cpu_flag(CIF_ASCE_PRIMARY);
  72 }
  73
  74 static inline void clear_user_asce(void)
  75 {
  76         S390_lowcore.user_asce = S390_lowcore.kernel_asce;
  77
  78         __ctl_load(S390_lowcore.user_asce, 1, 1);
  79         __ctl_load(S390_lowcore.user_asce, 7, 7);
  80 }
  81
  82 static inline void load_kernel_asce(void)
  83 {
  84         unsigned long asce;
  85
  86         __ctl_store(asce, 1, 1);
  87         if (asce != S390_lowcore.kernel_asce)
  88                 __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  89         set_cpu_flag(CIF_ASCE_PRIMARY);
  90 }
  91
  92 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  93                              struct task_struct *tsk)
  94 {
  95         int cpu = smp_processor_id();
  96
  97         S390_lowcore.user_asce = next->context.asce;
  98         if (prev == next)
  99                 return;
 100         cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
 101         cpumask_set_cpu(cpu, mm_cpumask(next));
 102         /* Clear old ASCE by loading the kernel ASCE. */
 103         __ctl_load(S390_lowcore.kernel_asce, 1, 1);
 104         __ctl_load(S390_lowcore.kernel_asce, 7, 7);
 105         cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
 106 }
 107
 108 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
 109 static inline void finish_arch_post_lock_switch(void)
 110 {
 111         struct task_struct *tsk = current;
 112         struct mm_struct *mm = tsk->mm;
 113
 114         load_kernel_asce();
 115         if (mm) {
 116                 preempt_disable();
 117                 while (atomic_read(&mm->context.flush_count))
 118                         cpu_relax();
 119
 120                 if (mm->context.flush_mm)
 121                         __tlb_flush_mm(mm);
 122                 preempt_enable();
 123         }
 124         set_fs(current->thread.mm_segment);
 125 }
 126
 127 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
 128 #define deactivate_mm(tsk,mm)   do { } while (0)
 129
 130 static inline void activate_mm(struct mm_struct *prev,
 131                                struct mm_struct *next)
 132 {
 133         switch_mm(prev, next, current);
 134         set_user_asce(next);
 135 }
 136
 137 #endif /* __S390_MMU_CONTEXT_H */