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         cpumask_clear(&mm->context.cpu_attach_mask);
  19         atomic_set(&mm->context.attach_count, 0);
  20         mm->context.flush_mm = 0;
  21         mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
  22         mm->context.asce_bits |= _ASCE_TYPE_REGION3;
  23 #ifdef CONFIG_PGSTE
  24         mm->context.alloc_pgste = page_table_allocate_pgste;
  25         mm->context.has_pgste = 0;
  26         mm->context.use_skey = 0;
  27 #endif
  28         mm->context.asce_limit = STACK_TOP_MAX;
  29         crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
  30         return 0;
  31 }
  32
  33 #define destroy_context(mm)             do { } while (0)
  34
  35 static inline void set_user_asce(struct mm_struct *mm)
  36 {
  37         S390_lowcore.user_asce = mm->context.asce_bits | __pa(mm->pgd);
  38         if (current->thread.mm_segment.ar4)
  39                 __ctl_load(S390_lowcore.user_asce, 7, 7);
  40         set_cpu_flag(CIF_ASCE);
  41 }
  42
  43 static inline void clear_user_asce(void)
  44 {
  45         S390_lowcore.user_asce = S390_lowcore.kernel_asce;
  46
  47         __ctl_load(S390_lowcore.user_asce, 1, 1);
  48         __ctl_load(S390_lowcore.user_asce, 7, 7);
  49 }
  50
  51 static inline void load_kernel_asce(void)
  52 {
  53         unsigned long asce;
  54
  55         __ctl_store(asce, 1, 1);
  56         if (asce != S390_lowcore.kernel_asce)
  57                 __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  58         set_cpu_flag(CIF_ASCE);
  59 }
  60
  61 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  62                              struct task_struct *tsk)
  63 {
  64         int cpu = smp_processor_id();
  65
  66         S390_lowcore.user_asce = next->context.asce_bits | __pa(next->pgd);
  67         if (prev == next)
  68                 return;
  69         if (MACHINE_HAS_TLB_LC)
  70                 cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
  71         /* Clear old ASCE by loading the kernel ASCE. */
  72         __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  73         __ctl_load(S390_lowcore.kernel_asce, 7, 7);
  74         atomic_inc(&next->context.attach_count);
  75         atomic_dec(&prev->context.attach_count);
  76         if (MACHINE_HAS_TLB_LC)
  77                 cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
  78 }
  79
  80 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
  81 static inline void finish_arch_post_lock_switch(void)
  82 {
  83         struct task_struct *tsk = current;
  84         struct mm_struct *mm = tsk->mm;
  85
  86         load_kernel_asce();
  87         if (mm) {
  88                 preempt_disable();
  89                 while (atomic_read(&mm->context.attach_count) >> 16)
  90                         cpu_relax();
  91
  92                 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
  93                 if (mm->context.flush_mm)
  94                         __tlb_flush_mm(mm);
  95                 preempt_enable();
  96         }
  97         set_fs(current->thread.mm_segment);
  98 }
  99
 100 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
 101 #define deactivate_mm(tsk,mm)   do { } while (0)
 102
 103 static inline void activate_mm(struct mm_struct *prev,
 104                                struct mm_struct *next)
 105 {
 106         switch_mm(prev, next, current);
 107         cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
 108         set_user_asce(next);
 109 }
 110
 111 static inline void arch_dup_mmap(struct mm_struct *oldmm,
 112                                  struct mm_struct *mm)
 113 {
 114         if (oldmm->context.asce_limit < mm->context.asce_limit)
 115                 crst_table_downgrade(mm, oldmm->context.asce_limit);
 116 }
 117
 118 static inline void arch_exit_mmap(struct mm_struct *mm)
 119 {
 120 }
 121
 122 static inline void arch_unmap(struct mm_struct *mm,
 123                         struct vm_area_struct *vma,
 124                         unsigned long start, unsigned long end)
 125 {
 126 }
 127
 128 static inline void arch_bprm_mm_init(struct mm_struct *mm,
 129                                      struct vm_area_struct *vma)
 130 {
 131 }
 132
 133 #endif /* __S390_MMU_CONTEXT_H */