release/src-rt-6.x.4708/linux/linux-2.6.36/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/tlbflush.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         atomic_set(&mm->context.attach_count, 0);
  21         mm->context.flush_mm = 0;
  22         mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
  23 #ifdef CONFIG_64BIT
  24         mm->context.asce_bits |= _ASCE_TYPE_REGION3;
  25 #endif
  26         if (current->mm->context.alloc_pgste) {
  27                 /*
  28                  * alloc_pgste indicates, that any NEW context will be created
  29                  * with extended page tables. The old context is unchanged. The
  30                  * page table allocation and the page table operations will
  31                  * look at has_pgste to distinguish normal and extended page
  32                  * tables. The only way to create extended page tables is to
  33                  * set alloc_pgste and then create a new context (e.g. dup_mm).
  34                  * The page table allocation is called after init_new_context
  35                  * and if has_pgste is set, it will create extended page
  36                  * tables.
  37                  */
  38                 mm->context.noexec = 0;
  39                 mm->context.has_pgste = 1;
  40                 mm->context.alloc_pgste = 1;
  41         } else {
  42                 mm->context.noexec = (user_mode == SECONDARY_SPACE_MODE);
  43                 mm->context.has_pgste = 0;
  44                 mm->context.alloc_pgste = 0;
  45         }
  46         mm->context.asce_limit = STACK_TOP_MAX;
  47         crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
  48         return 0;
  49 }
  50
  51 #define destroy_context(mm)             do { } while (0)
  52
  53 #ifndef __s390x__
  54 #define LCTL_OPCODE "lctl"
  55 #else
  56 #define LCTL_OPCODE "lctlg"
  57 #endif
  58
  59 static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
  60 {
  61         pgd_t *pgd = mm->pgd;
  62
  63         S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
  64         if (user_mode != HOME_SPACE_MODE) {
  65                 /* Load primary space page table origin. */
  66                 pgd = mm->context.noexec ? get_shadow_table(pgd) : pgd;
  67                 S390_lowcore.user_exec_asce = mm->context.asce_bits | __pa(pgd);
  68                 asm volatile(LCTL_OPCODE" 1,1,%0\n"
  69                              : : "m" (S390_lowcore.user_exec_asce) );
  70         } else
  71                 /* Load home space page table origin. */
  72                 asm volatile(LCTL_OPCODE" 13,13,%0"
  73                              : : "m" (S390_lowcore.user_asce) );
  74         set_fs(current->thread.mm_segment);
  75 }
  76
  77 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
  78                              struct task_struct *tsk)
  79 {
  80         cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
  81         update_mm(next, tsk);
  82         atomic_dec(&prev->context.attach_count);
  83         WARN_ON(atomic_read(&prev->context.attach_count) < 0);
  84         atomic_inc(&next->context.attach_count);
  85         /* Check for TLBs not flushed yet */
  86         if (next->context.flush_mm)
  87                 __tlb_flush_mm(next);
  88 }
  89
  90 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
  91 #define deactivate_mm(tsk,mm)   do { } while (0)
  92
  93 static inline void activate_mm(struct mm_struct *prev,
  94                                struct mm_struct *next)
  95 {
  96         switch_mm(prev, next, current);
  97 }
  98
  99 #endif /* __S390_MMU_CONTEXT_H */