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         atomic_set(&mm->context.attach_count, 0);
  19         mm->context.flush_mm = 0;
  20         mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
  21 #ifdef CONFIG_64BIT
  22         mm->context.asce_bits |= _ASCE_TYPE_REGION3;
  23 #endif
  24         if (current->mm && current->mm->context.alloc_pgste) {
  25                 /*
  26                  * alloc_pgste indicates, that any NEW context will be created
  27                  * with extended page tables. The old context is unchanged. The
  28                  * page table allocation and the page table operations will
  29                  * look at has_pgste to distinguish normal and extended page
  30                  * tables. The only way to create extended page tables is to
  31                  * set alloc_pgste and then create a new context (e.g. dup_mm).
  32                  * The page table allocation is called after init_new_context
  33                  * and if has_pgste is set, it will create extended page
  34                  * tables.
  35                  */
  36                 mm->context.has_pgste = 1;
  37                 mm->context.alloc_pgste = 1;
  38         } else {
  39                 mm->context.has_pgste = 0;
  40                 mm->context.alloc_pgste = 0;
  41         }
  42         mm->context.asce_limit = STACK_TOP_MAX;
  43         crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
  44         return 0;
  45 }
  46
  47 #define destroy_context(mm)             do { } while (0)
  48
  49 #ifndef CONFIG_64BIT
  50 #define LCTL_OPCODE "lctl"
  51 #else
  52 #define LCTL_OPCODE "lctlg"
  53 #endif
  54
  55 static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
  56 {
  57         pgd_t *pgd = mm->pgd;
  58
  59         S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
  60         if (addressing_mode != HOME_SPACE_MODE) {
  61                 /* Load primary space page table origin. */
  62                 asm volatile(LCTL_OPCODE" 1,1,%0\n"
  63                              : : "m" (S390_lowcore.user_asce) );
  64         } else
  65                 /* Load home space page table origin. */
  66                 asm volatile(LCTL_OPCODE" 13,13,%0"
  67                              : : "m" (S390_lowcore.user_asce) );
  68         set_fs(current->thread.mm_segment);
  69 }
  70
  71 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  72                              struct task_struct *tsk)
  73 {
  74         cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
  75         update_mm(next, tsk);
  76         atomic_dec(&prev->context.attach_count);
  77         WARN_ON(atomic_read(&prev->context.attach_count) < 0);
  78         atomic_inc(&next->context.attach_count);
  79         /* Check for TLBs not flushed yet */
  80         if (next->context.flush_mm)
  81                 __tlb_flush_mm(next);
  82 }
  83
  84 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
  85 #define deactivate_mm(tsk,mm)   do { } while (0)
  86
  87 static inline void activate_mm(struct mm_struct *prev,
  88                                struct mm_struct *next)
  89 {
  90         switch_mm(prev, next, current);
  91 }
  92
  93 static inline void arch_dup_mmap(struct mm_struct *oldmm,
  94                                  struct mm_struct *mm)
  95 {
  96 #ifdef CONFIG_64BIT
  97         if (oldmm->context.asce_limit < mm->context.asce_limit)
  98                 crst_table_downgrade(mm, oldmm->context.asce_limit);
  99 #endif
 100 }
 101
 102 static inline void arch_exit_mmap(struct mm_struct *mm)
 103 {
 104 }
 105
 106 #endif /* __S390_MMU_CONTEXT_H */