LXR linux/arch/parisc/include/asm/mmu

   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
  11static 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
  18extern unsigned long alloc_sid(void);
  19extern void free_sid(unsigned long);
  20
  21static inline int
  22init_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
  30static inline void
  31destroy_context(struct mm_struct *mm)
  32{
  33        free_sid(mm->context);
  34        mm->context = 0;
  35}
  36
  37static 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
  46static inline void load_context(mm_context_t context)
  47{
  48        mtsp(context, 3);
  49        mtctl(__space_to_prot(context), 8);
  50}
  51
  52static 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
  63static 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
  81