release/src-rt-6.x.4708/linux/linux-2.6.36/arch/parisc/include/asm/mmu_context.h

   1 #ifndef __PARISC_MMU_CONTEXT_H
   2 #define __PARISC_MMU_CONTEXT_H
   3
   4 #include <linux/mm.h>
   5 #include <linux/sched.h>
   6 #include <asm/atomic.h>
   7 #include <asm/pgalloc.h>
   8 #include <asm/pgtable.h>
   9 #include <asm-generic/mm_hooks.h>
  10
  11 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  12 {
  13 }
  14
  15 /* on PA-RISC, we actually have enough contexts to justify an allocator
  16  * for them.  prumpf */
  17
  18 extern unsigned long alloc_sid(void);
  19 extern void free_sid(unsigned long);
  20
  21 static inline int
  22 init_new_context(struct task_struct *tsk, struct mm_struct *mm)
  23 {
  24         BUG_ON(atomic_read(&mm->mm_users) != 1);
  25
  26         mm->context = alloc_sid();
  27         return 0;
  28 }
  29
  30 static inline void
  31 destroy_context(struct mm_struct *mm)
  32 {
  33         free_sid(mm->context);
  34         mm->context = 0;
  35 }
  36
  37 static inline unsigned long __space_to_prot(mm_context_t context)
  38 {
  39 #if SPACEID_SHIFT == 0
  40         return context << 1;
  41 #else
  42         return context >> (SPACEID_SHIFT - 1);
  43 #endif
  44 }
  45
  46 static inline void load_context(mm_context_t context)
  47 {
  48         mtsp(context, 3);
  49         mtctl(__space_to_prot(context), 8);
  50 }
  51
  52 static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
  53 {
  54
  55         if (prev != next) {
  56                 mtctl(__pa(next->pgd), 25);
  57                 load_context(next->context);
  58         }
  59 }
  60
  61 #define deactivate_mm(tsk,mm)   do { } while (0)
  62
  63 static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
  64 {
  65         /*
  66          * Activate_mm is our one chance to allocate a space id
  67          * for a new mm created in the exec path. There's also
  68          * some lazy tlb stuff, which is currently dead code, but
  69          * we only allocate a space id if one hasn't been allocated
  70          * already, so we should be OK.
  71          */
  72
  73         BUG_ON(next == &init_mm); /* Should never happen */
  74
  75         if (next->context == 0)
  76             next->context = alloc_sid();
  77
  78         switch_mm(prev,next,current);
  79 }
  80 #endif