arch/parisc/include/asm/mmu_context.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __PARISC_MMU_CONTEXT_H
   3 #define __PARISC_MMU_CONTEXT_H
   4
   5 #include <linux/mm.h>
   6 #include <linux/sched.h>
   7 #include <linux/atomic.h>
   8 #include <asm/pgalloc.h>
   9 #include <asm/pgtable.h>
  10 #include <asm-generic/mm_hooks.h>
  11
  12 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  13 {
  14 }
  15
  16 /* on PA-RISC, we actually have enough contexts to justify an allocator
  17  * for them.  prumpf */
  18
  19 extern unsigned long alloc_sid(void);
  20 extern void free_sid(unsigned long);
  21
  22 static inline int
  23 init_new_context(struct task_struct *tsk, struct mm_struct *mm)
  24 {
  25         BUG_ON(atomic_read(&mm->mm_users) != 1);
  26
  27         mm->context = alloc_sid();
  28         return 0;
  29 }
  30
  31 static inline void
  32 destroy_context(struct mm_struct *mm)
  33 {
  34         free_sid(mm->context);
  35         mm->context = 0;
  36 }
  37
  38 static inline unsigned long __space_to_prot(mm_context_t context)
  39 {
  40 #if SPACEID_SHIFT == 0
  41         return context << 1;
  42 #else
  43         return context >> (SPACEID_SHIFT - 1);
  44 #endif
  45 }
  46
  47 static inline void load_context(mm_context_t context)
  48 {
  49         mtsp(context, 3);
  50         mtctl(__space_to_prot(context), 8);
  51 }
  52
  53 static inline void switch_mm_irqs_off(struct mm_struct *prev,
  54                 struct mm_struct *next, struct task_struct *tsk)
  55 {
  56         if (prev != next) {
  57                 mtctl(__pa(next->pgd), 25);
  58                 load_context(next->context);
  59         }
  60 }
  61
  62 static inline void switch_mm(struct mm_struct *prev,
  63                 struct mm_struct *next, struct task_struct *tsk)
  64 {
  65         unsigned long flags;
  66
  67         if (prev == next)
  68                 return;
  69
  70         local_irq_save(flags);
  71         switch_mm_irqs_off(prev, next, tsk);
  72         local_irq_restore(flags);
  73 }
  74 #define switch_mm_irqs_off switch_mm_irqs_off
  75
  76 #define deactivate_mm(tsk,mm)   do { } while (0)
  77
  78 static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
  79 {
  80         /*
  81          * Activate_mm is our one chance to allocate a space id
  82          * for a new mm created in the exec path. There's also
  83          * some lazy tlb stuff, which is currently dead code, but
  84          * we only allocate a space id if one hasn't been allocated
  85          * already, so we should be OK.
  86          */
  87
  88         BUG_ON(next == &init_mm); /* Should never happen */
  89
  90         if (next->context == 0)
  91             next->context = alloc_sid();
  92
  93         switch_mm(prev,next,current);
  94 }
  95 #endif