arch/s390/include/asm/mmu_context.h

   1 /*
   2  *  include/asm-s390/mmu_context.h
   3  *
   4  *  S390 version
   5  *
   6  *  Derived from "include/asm-i386/mmu_context.h"
   7  */
   8
   9 #ifndef __S390_MMU_CONTEXT_H
  10 #define __S390_MMU_CONTEXT_H
  11
  12 #include <asm/pgalloc.h>
  13 #include <asm/uaccess.h>
  14 #include <asm-generic/mm_hooks.h>
  15
  16 static inline int init_new_context(struct task_struct *tsk,
  17                                    struct mm_struct *mm)
  18 {
  19         mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
  20 #ifdef CONFIG_64BIT
  21         mm->context.asce_bits |= _ASCE_TYPE_REGION3;
  22 #endif
  23         if (current->mm->context.alloc_pgste) {
  24                 /*
  25                  * alloc_pgste indicates, that any NEW context will be created
  26                  * with extended page tables. The old context is unchanged. The
  27                  * page table allocation and the page table operations will
  28                  * look at has_pgste to distinguish normal and extended page
  29                  * tables. The only way to create extended page tables is to
  30                  * set alloc_pgste and then create a new context (e.g. dup_mm).
  31                  * The page table allocation is called after init_new_context
  32                  * and if has_pgste is set, it will create extended page
  33                  * tables.
  34                  */
  35                 mm->context.noexec = 0;
  36                 mm->context.has_pgste = 1;
  37                 mm->context.alloc_pgste = 1;
  38         } else {
  39                 mm->context.noexec = s390_noexec;
  40                 mm->context.has_pgste = 0;
  41                 mm->context.alloc_pgste = 0;
  42         }
  43         mm->context.asce_limit = STACK_TOP_MAX;
  44         crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
  45         return 0;
  46 }
  47
  48 #define destroy_context(mm)             do { } while (0)
  49
  50 #ifndef __s390x__
  51 #define LCTL_OPCODE "lctl"
  52 #else
  53 #define LCTL_OPCODE "lctlg"
  54 #endif
  55
  56 static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
  57 {
  58         pgd_t *pgd = mm->pgd;
  59
  60         S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
  61         if (switch_amode) {
  62                 /* Load primary space page table origin. */
  63                 pgd = mm->context.noexec ? get_shadow_table(pgd) : pgd;
  64                 S390_lowcore.user_exec_asce = mm->context.asce_bits | __pa(pgd);
  65                 asm volatile(LCTL_OPCODE" 1,1,%0\n"
  66                              : : "m" (S390_lowcore.user_exec_asce) );
  67         } else
  68                 /* Load home space page table origin. */
  69                 asm volatile(LCTL_OPCODE" 13,13,%0"
  70                              : : "m" (S390_lowcore.user_asce) );
  71         set_fs(current->thread.mm_segment);
  72 }
  73
  74 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  75                              struct task_struct *tsk)
  76 {
  77         cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
  78         update_mm(next, tsk);
  79 }
  80
  81 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
  82 #define deactivate_mm(tsk,mm)   do { } while (0)
  83
  84 static inline void activate_mm(struct mm_struct *prev,
  85                                struct mm_struct *next)
  86 {
  87         switch_mm(prev, next, current);
  88 }
  89
  90 #endif /* __S390_MMU_CONTEXT_H */