arch/unicore32/include/asm/mmu_context.h

   1 /*
   2  * linux/arch/unicore32/include/asm/mmu_context.h
   3  *
   4  * Code specific to PKUnity SoC and UniCore ISA
   5  *
   6  * Copyright (C) 2001-2010 GUAN Xue-tao
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12 #ifndef __UNICORE_MMU_CONTEXT_H__
  13 #define __UNICORE_MMU_CONTEXT_H__
  14
  15 #include <linux/compiler.h>
  16 #include <linux/sched.h>
  17 #include <linux/mm.h>
  18 #include <linux/vmacache.h>
  19 #include <linux/io.h>
  20
  21 #include <asm/cacheflush.h>
  22 #include <asm/cpu-single.h>
  23
  24 #define init_new_context(tsk, mm)       0
  25
  26 #define destroy_context(mm)             do { } while (0)
  27
  28 /*
  29  * This is called when "tsk" is about to enter lazy TLB mode.
  30  *
  31  * mm:  describes the currently active mm context
  32  * tsk: task which is entering lazy tlb
  33  * cpu: cpu number which is entering lazy tlb
  34  *
  35  * tsk->mm will be NULL
  36  */
  37 static inline void
  38 enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  39 {
  40 }
  41
  42 /*
  43  * This is the actual mm switch as far as the scheduler
  44  * is concerned.  No registers are touched.  We avoid
  45  * calling the CPU specific function when the mm hasn't
  46  * actually changed.
  47  */
  48 static inline void
  49 switch_mm(struct mm_struct *prev, struct mm_struct *next,
  50           struct task_struct *tsk)
  51 {
  52         unsigned int cpu = smp_processor_id();
  53
  54         if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next)
  55                 cpu_switch_mm(next->pgd, next);
  56 }
  57
  58 #define deactivate_mm(tsk, mm)  do { } while (0)
  59 #define activate_mm(prev, next) switch_mm(prev, next, NULL)
  60
  61 /*
  62  * We are inserting a "fake" vma for the user-accessible vector page so
  63  * gdb and friends can get to it through ptrace and /proc/<pid>/mem.
  64  * But we also want to remove it before the generic code gets to see it
  65  * during process exit or the unmapping of it would  cause total havoc.
  66  * (the macro is used as remove_vma() is static to mm/mmap.c)
  67  */
  68 #define arch_exit_mmap(mm) \
  69 do { \
  70         struct vm_area_struct *high_vma = find_vma(mm, 0xffff0000); \
  71         if (high_vma) { \
  72                 BUG_ON(high_vma->vm_next);  /* it should be last */ \
  73                 if (high_vma->vm_prev) \
  74                         high_vma->vm_prev->vm_next = NULL; \
  75                 else \
  76                         mm->mmap = NULL; \
  77                 rb_erase(&high_vma->vm_rb, &mm->mm_rb); \
  78                 vmacache_invalidate(mm); \
  79                 mm->map_count--; \
  80                 remove_vma(high_vma); \
  81         } \
  82 } while (0)
  83
  84 static inline void arch_dup_mmap(struct mm_struct *oldmm,
  85                                  struct mm_struct *mm)
  86 {
  87 }
  88
  89 static inline void arch_unmap(struct mm_struct *mm,
  90                         struct vm_area_struct *vma,
  91                         unsigned long start, unsigned long end)
  92 {
  93 }
  94
  95 static inline void arch_bprm_mm_init(struct mm_struct *mm,
  96                                      struct vm_area_struct *vma)
  97 {
  98 }
  99
 100 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
 101                 bool write, bool foreign)
 102 {
 103         /* by default, allow everything */
 104         return true;
 105 }
 106
 107 static inline bool arch_pte_access_permitted(pte_t pte, bool write)
 108 {
 109         /* by default, allow everything */
 110         return true;
 111 }
 112 #endif