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 #ifdef CONFIG_64BIT
  23         mm->context.asce_bits |= _ASCE_TYPE_REGION3;
  24 #endif
  25         mm->context.has_pgste = 0;
  26         mm->context.use_skey = 0;
  27         mm->context.asce_limit = STACK_TOP_MAX;
  28         crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
  29         return 0;
  30 }
  31
  32 #define destroy_context(mm)             do { } while (0)
  33
  34 static inline void set_user_asce(struct mm_struct *mm)
  35 {
  36         S390_lowcore.user_asce = mm->context.asce_bits | __pa(mm->pgd);
  37         if (current->thread.mm_segment.ar4)
  38                 __ctl_load(S390_lowcore.user_asce, 7, 7);
  39         set_cpu_flag(CIF_ASCE);
  40 }
  41
  42 static inline void clear_user_asce(void)
  43 {
  44         S390_lowcore.user_asce = S390_lowcore.kernel_asce;
  45
  46         __ctl_load(S390_lowcore.user_asce, 1, 1);
  47         __ctl_load(S390_lowcore.user_asce, 7, 7);
  48 }
  49
  50 static inline void load_kernel_asce(void)
  51 {
  52         unsigned long asce;
  53
  54         __ctl_store(asce, 1, 1);
  55         if (asce != S390_lowcore.kernel_asce)
  56                 __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  57         set_cpu_flag(CIF_ASCE);
  58 }
  59
  60 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  61                              struct task_struct *tsk)
  62 {
  63         int cpu = smp_processor_id();
  64
  65         if (prev == next)
  66                 return;
  67         if (MACHINE_HAS_TLB_LC)
  68                 cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
  69         /* Clear old ASCE by loading the kernel ASCE. */
  70         __ctl_load(S390_lowcore.kernel_asce, 1, 1);
  71         __ctl_load(S390_lowcore.kernel_asce, 7, 7);
  72         atomic_inc(&next->context.attach_count);
  73         atomic_dec(&prev->context.attach_count);
  74         if (MACHINE_HAS_TLB_LC)
  75                 cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
  76         S390_lowcore.user_asce = next->context.asce_bits | __pa(next->pgd);
  77 }
  78
  79 #define finish_arch_post_lock_switch finish_arch_post_lock_switch
  80 static inline void finish_arch_post_lock_switch(void)
  81 {
  82         struct task_struct *tsk = current;
  83         struct mm_struct *mm = tsk->mm;
  84
  85         load_kernel_asce();
  86         if (mm) {
  87                 preempt_disable();
  88                 while (atomic_read(&mm->context.attach_count) >> 16)
  89                         cpu_relax();
  90
  91                 cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
  92                 if (mm->context.flush_mm)
  93                         __tlb_flush_mm(mm);
  94                 preempt_enable();
  95         }
  96         set_fs(current->thread.mm_segment);
  97 }
  98
  99 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
 100 #define deactivate_mm(tsk,mm)   do { } while (0)
 101
 102 static inline void activate_mm(struct mm_struct *prev,
 103                                struct mm_struct *next)
 104 {
 105         switch_mm(prev, next, current);
 106         cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
 107         set_user_asce(next);
 108 }
 109
 110 static inline void arch_dup_mmap(struct mm_struct *oldmm,
 111                                  struct mm_struct *mm)
 112 {
 113 #ifdef CONFIG_64BIT
 114         if (oldmm->context.asce_limit < mm->context.asce_limit)
 115                 crst_table_downgrade(mm, oldmm->context.asce_limit);
 116 #endif
 117 }
 118
 119 static inline void arch_exit_mmap(struct mm_struct *mm)
 120 {
 121 }
 122
 123 #endif /* __S390_MMU_CONTEXT_H */