mmu_context.h 2.7 KB

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  1. /*
  2. * linux/include/asm-arm/mmu_context.h
  3. *
  4. * Copyright (C) 1996 Russell King.
  5. *
  6. * This program is free software; you can redistribute it and/or modify
  7. * it under the terms of the GNU General Public License version 2 as
  8. * published by the Free Software Foundation.
  9. *
  10. * Changelog:
  11. * 27-06-1996 RMK Created
  12. */
  13. #ifndef __ASM_ARM_MMU_CONTEXT_H
  14. #define __ASM_ARM_MMU_CONTEXT_H
  15. #include <linux/compiler.h>
  16. #include <asm/cacheflush.h>
  17. #include <asm/proc-fns.h>
  18. void __check_kvm_seq(struct mm_struct *mm);
  19. #if __LINUX_ARM_ARCH__ >= 6
  20. /*
  21. * On ARMv6, we have the following structure in the Context ID:
  22. *
  23. * 31 7 0
  24. * +-------------------------+-----------+
  25. * | process ID | ASID |
  26. * +-------------------------+-----------+
  27. * | context ID |
  28. * +-------------------------------------+
  29. *
  30. * The ASID is used to tag entries in the CPU caches and TLBs.
  31. * The context ID is used by debuggers and trace logic, and
  32. * should be unique within all running processes.
  33. */
  34. #define ASID_BITS 8
  35. #define ASID_MASK ((~0) << ASID_BITS)
  36. extern unsigned int cpu_last_asid;
  37. void __init_new_context(struct task_struct *tsk, struct mm_struct *mm);
  38. void __new_context(struct mm_struct *mm);
  39. static inline void check_context(struct mm_struct *mm)
  40. {
  41. if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS))
  42. __new_context(mm);
  43. if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
  44. __check_kvm_seq(mm);
  45. }
  46. #define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0)
  47. #else
  48. static inline void check_context(struct mm_struct *mm)
  49. {
  50. if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq))
  51. __check_kvm_seq(mm);
  52. }
  53. #define init_new_context(tsk,mm) 0
  54. #endif
  55. #define destroy_context(mm) do { } while(0)
  56. /*
  57. * This is called when "tsk" is about to enter lazy TLB mode.
  58. *
  59. * mm: describes the currently active mm context
  60. * tsk: task which is entering lazy tlb
  61. * cpu: cpu number which is entering lazy tlb
  62. *
  63. * tsk->mm will be NULL
  64. */
  65. static inline void
  66. enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
  67. {
  68. }
  69. /*
  70. * This is the actual mm switch as far as the scheduler
  71. * is concerned. No registers are touched. We avoid
  72. * calling the CPU specific function when the mm hasn't
  73. * actually changed.
  74. */
  75. static inline void
  76. switch_mm(struct mm_struct *prev, struct mm_struct *next,
  77. struct task_struct *tsk)
  78. {
  79. #ifdef CONFIG_MMU
  80. unsigned int cpu = smp_processor_id();
  81. if (prev != next) {
  82. cpu_set(cpu, next->cpu_vm_mask);
  83. check_context(next);
  84. cpu_switch_mm(next->pgd, next);
  85. if (cache_is_vivt())
  86. cpu_clear(cpu, prev->cpu_vm_mask);
  87. }
  88. #endif
  89. }
  90. #define deactivate_mm(tsk,mm) do { } while (0)
  91. #define activate_mm(prev,next) switch_mm(prev, next, NULL)
  92. #endif