1 | /* |
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2 | * vmm.h - virtual memory management related operations |
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3 | * |
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4 | * Authors Ghassan Almaless (2008,2009,2010,2011, 2012) |
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5 | * Mohamed Lamine Karaoui (2015) |
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6 | * Alain Greiner (2016,2017,2018,2019) |
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7 | * |
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8 | * Copyright (c) UPMC Sorbonne Universites |
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9 | * |
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10 | * This file is part of ALMOS-MKH. |
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11 | * |
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12 | * ALMOS-MKH is free software; you can redistribute it and/or modify it |
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13 | * under the terms of the GNU General Public License as published by |
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14 | * the Free Software Foundation; version 2.0 of the License. |
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15 | * |
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16 | * ALMOS-MKH is distributed in the hope that it will be useful, but |
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17 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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19 | * General Public License for more details. |
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20 | * |
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21 | * You should have received a copy of the GNU General Public License |
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22 | * along with ALMOS-MKH; if not, write to the Free Software Foundation, |
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23 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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24 | */ |
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25 | |
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26 | #ifndef _VMM_H_ |
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27 | #define _VMM_H_ |
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28 | |
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29 | #include <hal_kernel_types.h> |
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30 | #include <bits.h> |
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31 | #include <list.h> |
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32 | #include <queuelock.h> |
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33 | #include <hal_gpt.h> |
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34 | #include <vseg.h> |
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35 | #include <page.h> |
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36 | |
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37 | /**** Forward declarations ****/ |
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38 | |
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39 | struct process_s; |
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40 | struct vseg_s; |
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41 | |
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42 | /********************************************************************************************* |
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43 | * This structure defines the STACK allocator used by the VMM to dynamically handle |
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44 | * vseg allocation or release requests for an user thread. |
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45 | * This allocator handles a fixed size array of fixed size slots in STACK zone of user space. |
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46 | * The stack size and the number of slots are defined by the CONFIG_VMM_STACK_SIZE, and |
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47 | * CONFIG_VMM_STACK_BASE parameters. |
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48 | * Each slot can contain one user stack vseg. The first 4 Kbytes page in the slot is not |
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49 | * mapped to detect stack overflow. |
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50 | * The slot index can be computed form the slot base address, and reversely. |
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51 | * All allocation / release operations are registered in the stack_bitmap, that completely |
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52 | * define the STACK zone status. |
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53 | ********************************************************************************************/ |
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54 | |
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55 | typedef struct stack_mgr_s |
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56 | { |
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57 | busylock_t lock; /*! lock protecting STACK allocator */ |
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58 | vpn_t vpn_base; /*! first page of STACK zone */ |
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59 | bitmap_t bitmap; /*! bit bector of allocated stacks */ |
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60 | } |
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61 | stack_mgr_t; |
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62 | |
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63 | /********************************************************************************************* |
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64 | * This structure defines the MMAP allocator used by the VMM to dynamically handle |
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65 | * MMAP vsegs requested or released by an user process. |
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66 | * This allocator should be only used in the reference cluster. |
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67 | * - allocation policy : all allocated vsegs occupy an integer number of pages that is |
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68 | * power of 2, and are aligned on a page boundary. The requested number of pages is |
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69 | * rounded if required. The first_free_vpn variable defines completely the MMAP zone state. |
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70 | * It is never decremented, as the released vsegs are simply registered in a zombi_list. |
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71 | * The relevant zombi_list is checked first for each allocation request. |
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72 | * - release policy : a released MMAP vseg is registered in an array of zombi_lists. |
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73 | * This array is indexed by ln(number of pages), and each entry contains the root of |
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74 | * a local list of zombi vsegs that have the same size. The physical memory allocated |
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75 | * for a zombi vseg descriptor is not released, to use the "list" field. |
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76 | * This physical memory allocated for MMAP vseg descriptors is actually released |
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77 | * when the VMM is destroyed. |
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78 | ********************************************************************************************/ |
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79 | |
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80 | typedef struct mmap_mgr_s |
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81 | { |
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82 | busylock_t lock; /*! lock protecting MMAP allocator */ |
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83 | vpn_t vpn_base; /*! first page of MMAP zone */ |
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84 | vpn_t vpn_size; /*! number of pages in MMAP zone */ |
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85 | vpn_t first_free_vpn; /*! first free page in MMAP zone */ |
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86 | list_entry_t zombi_list[32]; /*! array of roots of released vsegs lists */ |
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87 | } |
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88 | mmap_mgr_t; |
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89 | |
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90 | /********************************************************************************************* |
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91 | * This structure defines the Virtual Memory Manager for a given process in a given cluster. |
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92 | * This local VMM implements four main services: |
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93 | * 1) It contains the local copy of vseg list (VSL), only complete in referrence. |
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94 | * 2) It contains the local copy of the generic page table (GPT), only complete in reference. |
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95 | * 3) The stack manager dynamically allocates virtual memory space for the STACK vsegs. |
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96 | * 4) The mmap manager dynamically allocates virtual memory for the (FILE/ANON/REMOTE) vsegs. |
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97 | ******************************************************a************************************** |
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98 | * Implementation notes: |
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99 | * 1. In most clusters, the VSL and GPT are only partial copies of the reference VSL and GPT |
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100 | * structures, stored in the reference cluster. |
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101 | * 2. The VSL contains only local vsegs, but it is implemented as an xlist, and protected by |
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102 | * a remote_rwlock, because it can be accessed by a thread running in a remote cluster. |
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103 | * An exemple is the vmm_fork_copy() function. |
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104 | * 3. The GPT in the reference cluster can be directly accessed by remote threads to handle |
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105 | * false page-fault (page is mapped in the reference GPT, but the PTE copy is missing |
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106 | * in the local GPT). It is also protected by a remote_rwlock. |
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107 | ********************************************************************************************/ |
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108 | |
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109 | typedef struct vmm_s |
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110 | { |
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111 | remote_rwlock_t vsegs_lock; /*! lock protecting the local VSL */ |
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112 | xlist_entry_t vsegs_root; /*! Virtual Segment List (complete in reference) */ |
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113 | uint32_t vsegs_nr; /*! total number of local vsegs */ |
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114 | |
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115 | remote_rwlock_t gpt_lock; /*! lock protecting the local GPT */ |
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116 | gpt_t gpt; /*! Generic Page Table (complete in reference) */ |
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117 | |
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118 | stack_mgr_t stack_mgr; /*! embedded STACK vsegs allocator */ |
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119 | mmap_mgr_t mmap_mgr; /*! embedded MMAP vsegs allocator */ |
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120 | |
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121 | uint32_t pgfault_nr; /*! page fault counter (instrumentation) */ |
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122 | |
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123 | vpn_t kent_vpn_base; /*! kentry vseg first page */ |
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124 | vpn_t args_vpn_base; /*! args vseg first page */ |
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125 | vpn_t envs_vpn_base; /*! envs zone first page */ |
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126 | vpn_t heap_vpn_base; /*! envs zone first page */ |
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127 | vpn_t code_vpn_base; /*! code zone first page */ |
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128 | vpn_t data_vpn_base; /*! data zone first page */ |
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129 | |
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130 | intptr_t entry_point; /*! main thread entry point */ |
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131 | } |
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132 | vmm_t; |
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133 | |
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134 | /********************************************************************************************* |
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135 | * This function initialises the virtual memory manager attached to an user process. |
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136 | * - It initializes the STACK and MMAP allocators. |
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137 | * - It registers the "kentry", "args", "envs" vsegs in the VSL. |
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138 | * - It initializes the generic page table, calling the HAL specific hal_gpt_init() function. |
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139 | * - For TSAR it map all pages for the "kentry" vseg, that must be identity mapping. |
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140 | ******************************************************a************************************** |
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141 | * Implementation notes: |
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142 | * - The "code" and "data" vsegs are registered by the elf_load_process() function. |
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143 | * - The "stack" vsegs are dynamically created by the thread_user_create() function. |
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144 | * - The "file", "anon", "remote" vsegs are dynamically created by the mmap() syscall. |
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145 | ********************************************************************************************* |
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146 | * @ process : pointer on process descriptor |
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147 | * @ return 0 if success / return -1 if failure. |
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148 | ********************************************************************************************/ |
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149 | error_t vmm_init( struct process_s * process ); |
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150 | |
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151 | /********************************************************************************************* |
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152 | * This function displays on TXY0 the list or registered vsegs for a given <process>. |
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153 | * It must be executed by a thread running in reference cluster. |
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154 | * If the <mapping> argument is true, it displays for each vseg all mapped PTEs in GPT. |
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155 | ********************************************************************************************* |
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156 | * @ process : pointer on process descriptor. |
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157 | * @ mapping : detailed mapping if true. |
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158 | ********************************************************************************************/ |
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159 | void vmm_display( struct process_s * process, |
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160 | bool_t mapping ); |
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161 | |
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162 | /********************************************************************************************* |
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163 | * This function is called by the process_make_fork() function. It partially copies |
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164 | * the content of a remote parent process VMM to the local child process VMM: |
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165 | * - all DATA, MMAP, REMOTE vsegs registered in the parent VSL are registered in the child |
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166 | * VSL, and all valid GPT entries in parent GPT are copied to the child GPT. |
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167 | * The WRITABLE flag is reset and the COW flag is set in child GPT. |
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168 | * - all CODE vsegs registered in the parent VSL are registered in the child VSL, but the |
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169 | * GPT entries are not copied in the chilf GPT, that will be dynamically updated from |
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170 | * the .elf file when a page fault is reported. |
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171 | * - all FILE vsegs registered in the parent VSL are registered in the child VSL, and all |
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172 | * valid GPT entries in parent GPT are copied to the child GPT. The COW flag is not set. |
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173 | * - no STACK vseg is copied from parent VMM to child VMM, because the child STACK vseg |
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174 | * must be copied later from the cluster containing the user thread requesting the fork(). |
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175 | ********************************************************************************************* |
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176 | * @ child_process : local pointer on local child process descriptor. |
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177 | * @ parent_process_xp : extended pointer on remote parent process descriptor. |
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178 | * @ return 0 if success / return -1 if failure. |
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179 | ********************************************************************************************/ |
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180 | error_t vmm_fork_copy( struct process_s * child_process, |
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181 | xptr_t parent_process_xp ); |
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182 | |
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183 | /********************************************************************************************* |
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184 | * This function is called by the process_make_fork() function executing the fork syscall. |
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185 | * It set the COW flag, and reset the WRITABLE flag of all GPT entries of the DATA, MMAP, |
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186 | * and REMOTE vsegs of a process identified by the <process> argument. |
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187 | * It must be called by a thread running in the reference cluster, that contains the complete |
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188 | * VSL and GPT (use the rpc_vmm_set_cow_client() when the calling thread client is remote). |
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189 | * It updates all copies of the process in all clusters, to maintain coherence in GPT copies, |
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190 | * using the list of copies stored in the owner process, and using remote_write accesses to |
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191 | * update the remote GPTs. It atomically increment the pending_fork counter, in all involved |
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192 | * physical page descriptors. It cannot fail, as only mapped entries in GPTs are updated. |
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193 | ********************************************************************************************* |
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194 | * @ process : local pointer on local reference process descriptor. |
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195 | ********************************************************************************************/ |
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196 | void vmm_set_cow( struct process_s * process ); |
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197 | |
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198 | /********************************************************************************************* |
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199 | * This global function modifies a GPT entry identified by the <process> and <vpn> |
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200 | * arguments in all clusters containing a process copy. |
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201 | * It must be called by a thread running in the reference cluster. |
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202 | * It updates all copies of the process in all clusters, to maintain coherence in GPT copies, |
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203 | * using the list of copies stored in the owner process, and using remote_write accesses to |
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204 | * update the remote GPTs. It cannot fail, as only mapped entries in GPT copies are updated. |
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205 | ********************************************************************************************* |
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206 | * @ process : local pointer on local process descriptor. |
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207 | * @ vpn : PTE index. |
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208 | * @ attr : PTE / attributes. |
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209 | * @ ppn : PTE / physical page index. |
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210 | ********************************************************************************************/ |
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211 | void vmm_global_update_pte( struct process_s * process, |
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212 | vpn_t vpn, |
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213 | uint32_t attr, |
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214 | ppn_t ppn ); |
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215 | |
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216 | /********************************************************************************************* |
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217 | * This function deletes, in the local cluster, all vsegs registered in the VSL |
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218 | * of the process identified by the <process> argument. For each vseg: |
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219 | * - it unmaps all vseg PTEs from the GPT (release the physical pages when required). |
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220 | * - it removes the vseg from the local VSL. |
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221 | * - it releases the memory allocated to the local vseg descriptors. |
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222 | * - it releases the memory allocated to the GPT itself. |
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223 | ********************************************************************************************* |
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224 | * @ process : pointer on process descriptor. |
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225 | ********************************************************************************************/ |
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226 | void vmm_destroy( struct process_s * process ); |
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227 | |
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228 | /********************************************************************************************* |
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229 | * This function scans the list of vsegs registered in the VMM of a given process descriptor |
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230 | * to check if a given virtual region (defined by a base and size) overlap an existing vseg. |
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231 | ********************************************************************************************* |
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232 | * @ process : pointer on process descriptor. |
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233 | * @ base : region virtual base address. |
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234 | * @ size : region size (bytes). |
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235 | * @ returns NULL if no conflict / return conflicting vseg pointer if conflict. |
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236 | ********************************************************************************************/ |
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237 | vseg_t * vmm_check_conflict( struct process_s * process, |
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238 | vpn_t base, |
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239 | vpn_t size ); |
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240 | |
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241 | /********************************************************************************************* |
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242 | * This function allocates memory for a vseg descriptor, initialises it, and register it |
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243 | * in the VMM of the local process descriptor, that must be the reference process. |
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244 | * For the 'stack", "file", "anon", & "remote" types, it does not use the <base> argument, |
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245 | * but uses the STACK and MMAP virtual memory allocators. |
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246 | * It checks collision with all pre-existing vsegs. |
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247 | * To comply with the "on-demand" paging policy, this function does NOT modify the page table, |
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248 | * and does not allocate physical memory for vseg data. |
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249 | * It should be called by a local thread (could be a RPC thread if the client thread is not |
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250 | * running in the regerence cluster). |
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251 | ********************************************************************************************* |
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252 | * @ process : pointer on local processor descriptor. |
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253 | * @ type : vseg type. |
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254 | * @ base : vseg base address (not used for dynamically allocated vsegs). |
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255 | * @ size : vseg size (bytes). |
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256 | * @ file_offset : offset in file for CODE, DATA, FILE types. |
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257 | * @ file_size : can be smaller than "size" for DATA type. |
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258 | * @ mapper_xp : extended pointer on mapper for CODE, DATA, FILE types. |
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259 | * @ cxy : physical mapping cluster (for non distributed vsegs). |
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260 | * @ returns pointer on vseg if success / returns NULL if no memory, or conflict. |
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261 | ********************************************************************************************/ |
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262 | vseg_t * vmm_create_vseg( struct process_s * process, |
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263 | vseg_type_t type, |
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264 | intptr_t base, |
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265 | uint32_t size, |
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266 | uint32_t file_offset, |
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267 | uint32_t file_size, |
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268 | xptr_t mapper_xp, |
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269 | cxy_t cxy ); |
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270 | |
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271 | /********************************************************************************************* |
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272 | * This function removes from the local VMM of a process descriptor identified by the <pid> |
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273 | * argument a local vseg identified by its base address <vaddr> in user space. |
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274 | * It can be used for any type of vseg, but must be called by a local thread. |
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275 | * Use the RPC_VMM_DELETE_VSEG if the client thread is not local. |
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276 | * It does nothing if the process is not registered in the local cluster. |
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277 | * It does nothing if the vseg is not registered in the local process VSL. |
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278 | * - It removes from the local GPT all registered PTEs. If it is executed in the reference |
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279 | * cluster, it releases the referenced physical pages, to the relevant kmem allocator, |
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280 | * depending on vseg type and the pending forks counter. |
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281 | * - It removes the vseg from the local VSL, and release the vseg descriptor if not MMAP. |
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282 | ********************************************************************************************* |
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283 | * @ process : process identifier. |
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284 | * @ vaddr : vseg base address in user space. |
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285 | ********************************************************************************************/ |
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286 | void vmm_delete_vseg( pid_t pid, |
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287 | intptr_t vaddr ); |
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288 | |
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289 | /********************************************************************************************* |
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290 | * This function insert a new <vseg> descriptor in the VSL identifed by the <vmm> argument. |
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291 | * and updates the vmm field in the vseg descriptor. |
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292 | * It takes the lock protecting VSL. |
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293 | ********************************************************************************************* |
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294 | * @ vmm : local pointer on local VMM. |
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295 | * @ vseg : local pointer on local vseg descriptor. |
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296 | ********************************************************************************************/ |
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297 | void vmm_attach_vseg_to_vsl( vmm_t * vmm, |
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298 | vseg_t * vseg ); |
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299 | |
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300 | /********************************************************************************************* |
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301 | * This function removes a vseg identified by the <vseg> argument from the local VSL |
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302 | * identified by the <vmm> argument and release the memory allocated to vseg descriptor, |
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303 | * for all vseg types, BUT the MMAP type (i.e. ANON or REMOTE). |
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304 | * - If the vseg has not the STACK or MMAP type, it is simply removed from the VSL, |
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305 | * and vseg descriptor is released. |
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306 | * - If the vseg has the STACK type, it is removed from VSL, vseg descriptor is released, |
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307 | * and the stack slot is returned to the local VMM_STACK allocator. |
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308 | * - If the vseg has the MMAP type, it is removed from VSL and is registered in zombi_list |
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309 | * of the VMM_MMAP allocator for future reuse. The vseg descriptor is NOT released. |
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310 | ********************************************************************************************* |
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311 | * @ vmm : local pointer on local VMM. |
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312 | * @ vseg : local pointer on local vseg to be removed. |
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313 | ********************************************************************************************/ |
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314 | void vmm_detach_vseg_from_vsl( vmm_t * vmm, |
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315 | vseg_t * vseg ); |
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316 | |
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317 | /********************************************************************************************* |
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318 | * This function removes a given region (defined by a base address and a size) from |
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319 | * the VMM of a given process descriptor. This can modify the number of vsegs: |
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320 | * (a) if the region is not entirely mapped in an existing vseg, it's an error. |
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321 | * (b) if the region has same base and size as an existing vseg, the vseg is removed. |
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322 | * (c) if the removed region cut the vseg in two parts, it is modified. |
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323 | * (d) if the removed region cut the vseg in three parts, it is modified, and a new |
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324 | * vseg is created with same type. |
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325 | * FIXME [AG] this function should be called by a thread running in the reference cluster, |
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326 | * and the VMM should be updated in all process descriptors copies. |
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327 | ********************************************************************************************* |
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328 | * @ process : pointer on process descriptor |
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329 | * @ base : vseg base address |
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330 | * @ size : vseg size (bytes) |
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331 | ********************************************************************************************/ |
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332 | error_t vmm_resize_vseg( struct process_s * process, |
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333 | intptr_t base, |
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334 | intptr_t size ); |
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335 | |
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336 | /********************************************************************************************* |
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337 | * This low-level function scan the local VSL in <vmm> to find the unique vseg containing |
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338 | * a given virtual address <vaddr>. |
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339 | * It is called by the vmm_get_vseg(), vmm_get_pte(), and vmm_resize_vseg() functions. |
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340 | ********************************************************************************************* |
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341 | * @ vmm : pointer on the process VMM. |
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342 | * @ vaddr : virtual address. |
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343 | * @ return vseg pointer if success / return NULL if not found. |
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344 | ********************************************************************************************/ |
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345 | struct vseg_s * vmm_vseg_from_vaddr( vmm_t * vmm, |
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346 | intptr_t vaddr ); |
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347 | |
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348 | /********************************************************************************************* |
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349 | * This function checks that a given virtual address is contained in a registered vseg. |
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350 | * It can be called by any thread running in any cluster: |
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351 | * - if the vseg is registered in the local process VMM, it returns the local vseg pointer. |
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352 | * - if the vseg is missing in local VMM, it uses a RPC to get it from the reference cluster, |
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353 | * register it in local VMM and returns the local vseg pointer, if success. |
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354 | * - it returns an user error if the vseg is missing in the reference VMM, or if there is |
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355 | * not enough memory for a new vseg descriptor in the calling thread cluster. |
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356 | ********************************************************************************************* |
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357 | * @ process : [in] pointer on process descriptor |
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358 | * @ vaddr : [in] virtual address |
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359 | * @ vseg : [out] local pointer on local vseg |
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360 | * @ returns 0 if success / returns -1 if user error (out of segment). |
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361 | ********************************************************************************************/ |
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362 | error_t vmm_get_vseg( struct process_s * process, |
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363 | intptr_t vaddr, |
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364 | vseg_t ** vseg ); |
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365 | |
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366 | /********************************************************************************************* |
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367 | * This function is called by the generic exception handler in case of page-fault event, |
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368 | * detected for a given <vpn>. The <process> argument is used to access the relevant VMM. |
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369 | * It checks the missing VPN and returns an user error if it is not in a registered vseg. |
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370 | * For a legal VPN, there is actually 3 cases: |
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371 | * 1) if the missing VPN belongs to a private vseg (STACK or CODE segment types, non |
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372 | * replicated in all clusters), it allocates a new physical page, computes the attributes, |
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373 | * depending on vseg type, and updates directly the local GPT. |
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374 | * 2) if the missing VPN belongs to a public vseg, it can be a false page-fault, when the VPN |
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375 | * is mapped in the reference GPT, but not in the local GPT. For this false page-fault, |
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376 | * the local GPT is simply updated from the reference GPT. |
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377 | * 3) if the missing VPN is public, and unmapped in the reference GPT, it's a true page fault. |
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378 | * The calling thread allocates a new physical page, computes the attributes, depending |
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379 | * on vseg type, and updates directly (without RPC) the local GPT and the reference GPT. |
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380 | * Other GPT copies will updated on demand. |
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381 | * Concurrent accesses to the GPT are handled, thanks to the |
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382 | * remote_rwlock protecting each GPT copy. |
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383 | ********************************************************************************************* |
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384 | * @ process : local pointer on local process. |
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385 | * @ vpn : VPN of the missing PTE. |
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386 | * @ returns EXCP_NON_FATAL / EXCP_USER_ERROR / EXCP_KERNEL_PANIC after analysis |
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387 | ********************************************************************************************/ |
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388 | error_t vmm_handle_page_fault( struct process_s * process, |
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389 | vpn_t vpn ); |
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390 | |
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391 | /********************************************************************************************* |
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392 | * This function is called by the generic exception handler in case of WRITE violation event, |
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393 | * detected for a given <vpn>. The <process> argument is used to access the relevant VMM. |
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394 | * It returns a kernel panic if VPN is not in a registered vseg or is not mapped. |
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395 | * For a legal mapped vseg there is two cases: |
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396 | * 1) If the missing VPN belongs to a private vseg (STACK or CODE segment types, non |
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397 | * replicated in all clusters), it access the local GPT to get the current PPN and ATTR. |
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398 | * It access the forks counter in the current physical page descriptor. |
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399 | * If there is a pending fork, it allocates a new physical page from the cluster defined |
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400 | * by the vseg type, copies the old physical page content to the new physical page, |
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401 | * and decrements the pending_fork counter in old physical page descriptor. |
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402 | * Finally, it reset the COW flag and set the WRITE flag in local GPT. |
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403 | * 2) If the missing VPN is public, it access the reference GPT to get the current PPN and |
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404 | * ATTR. It access the forks counter in the current physical page descriptor. |
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405 | * If there is a pending fork, it allocates a new physical page from the cluster defined |
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406 | * by the vseg type, copies the old physical page content to the new physical page, |
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407 | * and decrements the pending_fork counter in old physical page descriptor. |
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408 | * Finally it calls the vmm_global_update_pte() function to reset the COW flag and set |
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409 | * the WRITE flag in all the GPT copies, using a RPC if the reference cluster is remote. |
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410 | * In both cases, concurrent accesses to the GPT are protected by the remote_rwlock |
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411 | * atached to the GPT copy in VMM. |
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412 | ********************************************************************************************* |
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413 | * @ process : pointer on local process descriptor copy. |
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414 | * @ vpn : VPN of the faulting PTE. |
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415 | * @ returns EXCP_NON_FATAL / EXCP_USER_ERROR / EXCP_KERNEL_PANIC after analysis |
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416 | ********************************************************************************************/ |
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417 | error_t vmm_handle_cow( struct process_s * process, |
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418 | vpn_t vpn ); |
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419 | |
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420 | /********************************************************************************************* |
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421 | * This function is called by the vmm_get_pte() function when a page is unmapped. |
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422 | * Depending on the vseg type, defined by the <vseg> argument, it returns the PPN |
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423 | * (Physical Page Number) associated to a missing page defined by the <vpn> argument. |
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424 | * - For the FILE type, it returns directly the physical page from the file mapper. |
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425 | * - For the CODE and DATA types, it allocates a new physical page from the cluster defined |
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426 | * by the <vseg->cxy> field, or by the <vpn> MSB bits for a distributed vseg, |
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427 | * and initialize this page from the .elf file mapper. |
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428 | * - For all other types, it allocates a new physical page from the cluster defined |
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429 | * by the <vseg->cxy> field, or by the <vpn> MSB bits for a distributed vseg, |
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430 | * but the new page is not initialized. |
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431 | ********************************************************************************************* |
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432 | * @ vseg : local pointer on vseg containing the mising page. |
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433 | * @ vpn : Virtual Page Number identifying the missing page. |
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434 | * @ ppn : [out] returned Physical Page Number. |
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435 | * return 0 if success / return EINVAL or ENOMEM if error. |
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436 | ********************************************************************************************/ |
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437 | error_t vmm_get_one_ppn( vseg_t * vseg, |
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438 | vpn_t vpn, |
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439 | ppn_t * ppn ); |
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440 | |
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441 | |
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442 | #endif /* _VMM_H_ */ |
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