root/arch/unicore32/include/asm/mmu_context.h

INCLUDED FROM

DEFINITIONS

1. enter_lazy_tlb
2. switch_mm
3. arch_dup_mmap
4. arch_unmap
5. arch_bprm_mm_init
6. arch_vma_access_permitted

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * linux/arch/unicore32/include/asm/mmu_context.h
   4  *
   5  * Code specific to PKUnity SoC and UniCore ISA
   6  *
   7  * Copyright (C) 2001-2010 GUAN Xue-tao
   8  */
   9 #ifndef __UNICORE_MMU_CONTEXT_H__
  10 #define __UNICORE_MMU_CONTEXT_H__
  11 
  12 #include <linux/compiler.h>
  13 #include <linux/sched.h>
  14 #include <linux/mm.h>
  15 #include <linux/vmacache.h>
  16 #include <linux/io.h>
  17 
  18 #include <asm/cacheflush.h>
  19 #include <asm/cpu-single.h>
  20 
  21 #define init_new_context(tsk, mm)       0
  22 
  23 #define destroy_context(mm)             do { } while (0)
  24 
  25 /*
  26  * This is called when "tsk" is about to enter lazy TLB mode.
  27  *
  28  * mm:  describes the currently active mm context
  29  * tsk: task which is entering lazy tlb
  30  * cpu: cpu number which is entering lazy tlb
  31  *
  32  * tsk->mm will be NULL
  33  */
  34 static inline void
  35 enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  36 {
  37 }
  38 
  39 /*
  40  * This is the actual mm switch as far as the scheduler
  41  * is concerned.  No registers are touched.  We avoid
  42  * calling the CPU specific function when the mm hasn't
  43  * actually changed.
  44  */
  45 static inline void
  46 switch_mm(struct mm_struct *prev, struct mm_struct *next,
  47           struct task_struct *tsk)
  48 {
  49         unsigned int cpu = smp_processor_id();
  50 
  51         if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next)
  52                 cpu_switch_mm(next->pgd, next);
  53 }
  54 
  55 #define deactivate_mm(tsk, mm)  do { } while (0)
  56 #define activate_mm(prev, next) switch_mm(prev, next, NULL)
  57 
  58 /*
  59  * We are inserting a "fake" vma for the user-accessible vector page so
  60  * gdb and friends can get to it through ptrace and /proc/<pid>/mem.
  61  * But we also want to remove it before the generic code gets to see it
  62  * during process exit or the unmapping of it would  cause total havoc.
  63  * (the macro is used as remove_vma() is static to mm/mmap.c)
  64  */
  65 #define arch_exit_mmap(mm) \
  66 do { \
  67         struct vm_area_struct *high_vma = find_vma(mm, 0xffff0000); \
  68         if (high_vma) { \
  69                 BUG_ON(high_vma->vm_next);  /* it should be last */ \
  70                 if (high_vma->vm_prev) \
  71                         high_vma->vm_prev->vm_next = NULL; \
  72                 else \
  73                         mm->mmap = NULL; \
  74                 rb_erase(&high_vma->vm_rb, &mm->mm_rb); \
  75                 vmacache_invalidate(mm); \
  76                 mm->map_count--; \
  77                 remove_vma(high_vma); \
  78         } \
  79 } while (0)
  80 
  81 static inline int arch_dup_mmap(struct mm_struct *oldmm,
  82                                 struct mm_struct *mm)
  83 {
  84         return 0;
  85 }
  86 
  87 static inline void arch_unmap(struct mm_struct *mm,
  88                         unsigned long start, unsigned long end)
  89 {
  90 }
  91 
  92 static inline void arch_bprm_mm_init(struct mm_struct *mm,
  93                                      struct vm_area_struct *vma)
  94 {
  95 }
  96 
  97 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
  98                 bool write, bool execute, bool foreign)
  99 {
 100         /* by default, allow everything */
 101         return true;
 102 }
 103 #endif