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