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1 /* include/asm-generic/tlb.h |
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2 * |
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3 * Generic TLB shootdown code |
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4 * |
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5 * Copyright 2001 Red Hat, Inc. |
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6 * Based on code from mm/memory.c Copyright Linus Torvalds and others. |
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7 * |
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8 * This program is free software; you can redistribute it and/or |
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9 * modify it under the terms of the GNU General Public License |
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10 * as published by the Free Software Foundation; either version |
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11 * 2 of the License, or (at your option) any later version. |
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12 */ |
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13 #ifndef _ASM_GENERIC__TLB_H |
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14 #define _ASM_GENERIC__TLB_H |
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15 |
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16 #include <linux/swap.h> |
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17 #include <asm/pgalloc.h> |
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18 #include <asm/tlbflush.h> |
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19 |
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20 /* |
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21 * For UP we don't need to worry about TLB flush |
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22 * and page free order so much.. |
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23 */ |
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24 #ifdef CONFIG_SMP |
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25 #ifdef ARCH_FREE_PTR_NR |
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26 #define FREE_PTR_NR ARCH_FREE_PTR_NR |
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27 #else |
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28 #define FREE_PTE_NR 506 |
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29 #endif |
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30 #define tlb_fast_mode(tlb) ((tlb)->nr == ~0U) |
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31 #else |
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32 #define FREE_PTE_NR 1 |
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33 #define tlb_fast_mode(tlb) 1 |
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34 #endif |
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35 |
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36 /* struct mmu_gather is an opaque type used by the mm code for passing around |
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37 * any data needed by arch specific code for tlb_remove_page. |
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38 */ |
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39 struct mmu_gather { |
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40 struct mm_struct *mm; |
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41 unsigned int nr; /* set to ~0U means fast mode */ |
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42 unsigned int need_flush;/* Really unmapped some ptes? */ |
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43 unsigned int fullmm; /* non-zero means full mm flush */ |
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44 struct page * pages[FREE_PTE_NR]; |
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45 }; |
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46 |
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47 /* Users of the generic TLB shootdown code must declare this storage space. */ |
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48 DECLARE_PER_CPU(struct mmu_gather, mmu_gathers); |
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49 |
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50 /* tlb_gather_mmu |
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51 * Return a pointer to an initialized struct mmu_gather. |
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52 */ |
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53 static inline struct mmu_gather * |
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54 tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush) |
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55 { |
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56 struct mmu_gather *tlb = &get_cpu_var(mmu_gathers); |
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57 |
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58 tlb->mm = mm; |
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59 |
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60 /* Use fast mode if only one CPU is online */ |
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61 tlb->nr = num_online_cpus() > 1 ? 0U : ~0U; |
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62 |
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63 tlb->fullmm = full_mm_flush; |
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64 |
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65 return tlb; |
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66 } |
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67 |
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68 static inline void |
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69 tlb_flush_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) |
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70 { |
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71 if (!tlb->need_flush) |
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72 return; |
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73 tlb->need_flush = 0; |
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74 tlb_flush(tlb); |
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75 if (!tlb_fast_mode(tlb)) { |
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76 free_pages_and_swap_cache(tlb->pages, tlb->nr); |
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77 tlb->nr = 0; |
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78 } |
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79 } |
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80 |
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81 /* tlb_finish_mmu |
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82 * Called at the end of the shootdown operation to free up any resources |
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83 * that were required. |
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84 */ |
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85 static inline void |
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86 tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) |
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87 { |
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88 tlb_flush_mmu(tlb, start, end); |
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89 |
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90 /* keep the page table cache within bounds */ |
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91 check_pgt_cache(); |
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92 |
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93 put_cpu_var(mmu_gathers); |
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94 } |
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95 |
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96 /* tlb_remove_page |
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97 * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while |
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98 * handling the additional races in SMP caused by other CPUs caching valid |
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99 * mappings in their TLBs. |
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100 */ |
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101 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) |
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102 { |
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103 tlb->need_flush = 1; |
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104 if (tlb_fast_mode(tlb)) { |
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105 free_page_and_swap_cache(page); |
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106 return; |
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107 } |
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108 tlb->pages[tlb->nr++] = page; |
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109 if (tlb->nr >= FREE_PTE_NR) |
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110 tlb_flush_mmu(tlb, 0, 0); |
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111 } |
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112 |
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113 /** |
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114 * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation. |
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115 * |
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116 * Record the fact that pte's were really umapped in ->need_flush, so we can |
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117 * later optimise away the tlb invalidate. This helps when userspace is |
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118 * unmapping already-unmapped pages, which happens quite a lot. |
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119 */ |
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120 #define tlb_remove_tlb_entry(tlb, ptep, address) \ |
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121 do { \ |
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122 tlb->need_flush = 1; \ |
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123 __tlb_remove_tlb_entry(tlb, ptep, address); \ |
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124 } while (0) |
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125 |
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126 #define pte_free_tlb(tlb, ptep) \ |
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127 do { \ |
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128 tlb->need_flush = 1; \ |
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129 __pte_free_tlb(tlb, ptep); \ |
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130 } while (0) |
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131 |
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132 #ifndef __ARCH_HAS_4LEVEL_HACK |
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133 #define pud_free_tlb(tlb, pudp) \ |
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134 do { \ |
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135 tlb->need_flush = 1; \ |
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136 __pud_free_tlb(tlb, pudp); \ |
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137 } while (0) |
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138 #endif |
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139 |
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140 #define pmd_free_tlb(tlb, pmdp) \ |
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141 do { \ |
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142 tlb->need_flush = 1; \ |
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143 __pmd_free_tlb(tlb, pmdp); \ |
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144 } while (0) |
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145 |
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146 #define tlb_migrate_finish(mm) do {} while (0) |
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147 |
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148 #endif /* _ASM_GENERIC__TLB_H */ |