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1424 | jermar | 1 | /* |
2071 | jermar | 2 | * Copyright (c) 2006 Jakub Jermar |
1424 | jermar | 3 | * All rights reserved. |
4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * - Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
1757 | jermar | 29 | /** @addtogroup genericmm |
1702 | cejka | 30 | * @{ |
31 | */ |
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32 | |||
1424 | jermar | 33 | /** |
1702 | cejka | 34 | * @file |
1424 | jermar | 35 | * @brief Backend for address space areas backed by an ELF image. |
36 | */ |
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37 | |||
2000 | decky | 38 | #include <lib/elf.h> |
1424 | jermar | 39 | #include <debug.h> |
40 | #include <arch/types.h> |
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41 | #include <mm/as.h> |
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42 | #include <mm/frame.h> |
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43 | #include <mm/slab.h> |
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1426 | jermar | 44 | #include <mm/page.h> |
45 | #include <genarch/mm/page_pt.h> |
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46 | #include <genarch/mm/page_ht.h> |
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1424 | jermar | 47 | #include <align.h> |
48 | #include <memstr.h> |
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49 | #include <macros.h> |
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50 | #include <arch.h> |
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51 | |||
2076 | jermar | 52 | #ifdef CONFIG_VIRT_IDX_DCACHE |
53 | #include <arch/mm/cache.h> |
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54 | #endif |
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55 | |||
1780 | jermar | 56 | static int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access); |
57 | static void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame); |
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1426 | jermar | 58 | static void elf_share(as_area_t *area); |
1424 | jermar | 59 | |
60 | mem_backend_t elf_backend = { |
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61 | .page_fault = elf_page_fault, |
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62 | .frame_free = elf_frame_free, |
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1426 | jermar | 63 | .share = elf_share |
1424 | jermar | 64 | }; |
65 | |||
66 | /** Service a page fault in the ELF backend address space area. |
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67 | * |
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68 | * The address space area and page tables must be already locked. |
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69 | * |
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70 | * @param area Pointer to the address space area. |
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71 | * @param addr Faulting virtual address. |
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72 | * @param access Access mode that caused the fault (i.e. read/write/exec). |
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73 | * |
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2132 | jermar | 74 | * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. |
75 | * serviced). |
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1424 | jermar | 76 | */ |
1780 | jermar | 77 | int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access) |
1424 | jermar | 78 | { |
1425 | jermar | 79 | elf_header_t *elf = area->backend_data.elf; |
80 | elf_segment_header_t *entry = area->backend_data.segment; |
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1426 | jermar | 81 | btree_node_t *leaf; |
1780 | jermar | 82 | uintptr_t base, frame; |
1424 | jermar | 83 | index_t i; |
2134 | jermar | 84 | bool dirty = false; |
1424 | jermar | 85 | |
86 | if (!as_area_check_access(area, access)) |
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87 | return AS_PF_FAULT; |
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88 | |||
2132 | jermar | 89 | ASSERT((addr >= entry->p_vaddr) && |
90 | (addr < entry->p_vaddr + entry->p_memsz)); |
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1424 | jermar | 91 | i = (addr - entry->p_vaddr) >> PAGE_WIDTH; |
1780 | jermar | 92 | base = (uintptr_t) (((void *) elf) + entry->p_offset); |
1424 | jermar | 93 | ASSERT(ALIGN_UP(base, FRAME_SIZE) == base); |
1426 | jermar | 94 | |
95 | if (area->sh_info) { |
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96 | bool found = false; |
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97 | |||
98 | /* |
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99 | * The address space area is shared. |
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100 | */ |
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101 | |||
102 | mutex_lock(&area->sh_info->lock); |
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1780 | jermar | 103 | frame = (uintptr_t) btree_search(&area->sh_info->pagemap, |
1426 | jermar | 104 | ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf); |
105 | if (!frame) { |
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106 | int i; |
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107 | |||
108 | /* |
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109 | * Workaround for valid NULL address. |
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110 | */ |
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111 | |||
112 | for (i = 0; i < leaf->keys; i++) { |
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2132 | jermar | 113 | if (leaf->key[i] == |
114 | ALIGN_DOWN(addr, PAGE_SIZE)) { |
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1426 | jermar | 115 | found = true; |
116 | break; |
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117 | } |
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118 | } |
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119 | } |
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120 | if (frame || found) { |
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1546 | jermar | 121 | frame_reference_add(ADDR2PFN(frame)); |
2132 | jermar | 122 | page_mapping_insert(AS, addr, frame, |
123 | as_area_get_flags(area)); |
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124 | if (!used_space_insert(area, |
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125 | ALIGN_DOWN(addr, PAGE_SIZE), 1)) |
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1426 | jermar | 126 | panic("Could not insert used space.\n"); |
127 | mutex_unlock(&area->sh_info->lock); |
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128 | return AS_PF_OK; |
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129 | } |
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130 | } |
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1424 | jermar | 131 | |
1426 | jermar | 132 | /* |
2132 | jermar | 133 | * The area is either not shared or the pagemap does not contain the |
134 | * mapping. |
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1426 | jermar | 135 | */ |
136 | |||
2132 | jermar | 137 | if (ALIGN_DOWN(addr, PAGE_SIZE) + PAGE_SIZE < |
138 | entry->p_vaddr + entry->p_filesz) { |
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1424 | jermar | 139 | /* |
140 | * Initialized portion of the segment. The memory is backed |
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141 | * directly by the content of the ELF image. Pages are |
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142 | * only copied if the segment is writable so that there |
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143 | * can be more instantions of the same memory ELF image |
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144 | * used at a time. Note that this could be later done |
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145 | * as COW. |
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146 | */ |
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147 | if (entry->p_flags & PF_W) { |
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1780 | jermar | 148 | frame = (uintptr_t)frame_alloc(ONE_FRAME, 0); |
2132 | jermar | 149 | memcpy((void *) PA2KA(frame), |
150 | (void *) (base + i * FRAME_SIZE), FRAME_SIZE); |
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2134 | jermar | 151 | dirty = true; |
152 | |||
1426 | jermar | 153 | if (area->sh_info) { |
1546 | jermar | 154 | frame_reference_add(ADDR2PFN(frame)); |
2132 | jermar | 155 | btree_insert(&area->sh_info->pagemap, |
156 | ALIGN_DOWN(addr, PAGE_SIZE) - area->base, |
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157 | (void *) frame, leaf); |
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1426 | jermar | 158 | } |
159 | |||
1424 | jermar | 160 | } else { |
161 | frame = KA2PA(base + i*FRAME_SIZE); |
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162 | } |
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2132 | jermar | 163 | } else if (ALIGN_DOWN(addr, PAGE_SIZE) >= |
164 | ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) { |
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1424 | jermar | 165 | /* |
166 | * This is the uninitialized portion of the segment. |
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167 | * It is not physically present in the ELF image. |
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168 | * To resolve the situation, a frame must be allocated |
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169 | * and cleared. |
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170 | */ |
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1780 | jermar | 171 | frame = (uintptr_t)frame_alloc(ONE_FRAME, 0); |
1424 | jermar | 172 | memsetb(PA2KA(frame), FRAME_SIZE, 0); |
2134 | jermar | 173 | dirty = true; |
1426 | jermar | 174 | |
175 | if (area->sh_info) { |
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1546 | jermar | 176 | frame_reference_add(ADDR2PFN(frame)); |
2132 | jermar | 177 | btree_insert(&area->sh_info->pagemap, |
178 | ALIGN_DOWN(addr, PAGE_SIZE) - area->base, |
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179 | (void *) frame, leaf); |
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1426 | jermar | 180 | } |
181 | |||
1424 | jermar | 182 | } else { |
183 | size_t size; |
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184 | /* |
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185 | * The mixed case. |
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186 | * The lower part is backed by the ELF image and |
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187 | * the upper part is anonymous memory. |
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188 | */ |
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189 | size = entry->p_filesz - (i<<PAGE_WIDTH); |
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1780 | jermar | 190 | frame = (uintptr_t)frame_alloc(ONE_FRAME, 0); |
1424 | jermar | 191 | memsetb(PA2KA(frame) + size, FRAME_SIZE - size, 0); |
2132 | jermar | 192 | memcpy((void *) PA2KA(frame), (void *) (base + i * FRAME_SIZE), |
193 | size); |
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2134 | jermar | 194 | dirty = true; |
1426 | jermar | 195 | |
196 | if (area->sh_info) { |
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1546 | jermar | 197 | frame_reference_add(ADDR2PFN(frame)); |
2132 | jermar | 198 | btree_insert(&area->sh_info->pagemap, |
199 | ALIGN_DOWN(addr, PAGE_SIZE) - area->base, |
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200 | (void *) frame, leaf); |
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1426 | jermar | 201 | } |
202 | |||
1424 | jermar | 203 | } |
204 | |||
1426 | jermar | 205 | if (area->sh_info) |
206 | mutex_unlock(&area->sh_info->lock); |
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207 | |||
1424 | jermar | 208 | page_mapping_insert(AS, addr, frame, as_area_get_flags(area)); |
1426 | jermar | 209 | if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1)) |
210 | panic("Could not insert used space.\n"); |
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1424 | jermar | 211 | |
212 | return AS_PF_OK; |
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213 | } |
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214 | |||
215 | /** Free a frame that is backed by the ELF backend. |
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216 | * |
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217 | * The address space area and page tables must be already locked. |
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218 | * |
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219 | * @param area Pointer to the address space area. |
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220 | * @param page Page that is mapped to frame. Must be aligned to PAGE_SIZE. |
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221 | * @param frame Frame to be released. |
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222 | * |
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223 | */ |
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1780 | jermar | 224 | void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame) |
1424 | jermar | 225 | { |
1425 | jermar | 226 | elf_header_t *elf = area->backend_data.elf; |
227 | elf_segment_header_t *entry = area->backend_data.segment; |
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1780 | jermar | 228 | uintptr_t base; |
1424 | jermar | 229 | index_t i; |
230 | |||
2132 | jermar | 231 | ASSERT((page >= entry->p_vaddr) && |
232 | (page < entry->p_vaddr + entry->p_memsz)); |
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1424 | jermar | 233 | i = (page - entry->p_vaddr) >> PAGE_WIDTH; |
1780 | jermar | 234 | base = (uintptr_t) (((void *) elf) + entry->p_offset); |
1424 | jermar | 235 | ASSERT(ALIGN_UP(base, FRAME_SIZE) == base); |
236 | |||
2132 | jermar | 237 | if (page + PAGE_SIZE < |
238 | ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) { |
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1424 | jermar | 239 | if (entry->p_flags & PF_W) { |
240 | /* |
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2132 | jermar | 241 | * Free the frame with the copy of writable segment |
242 | * data. |
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1424 | jermar | 243 | */ |
1760 | palkovsky | 244 | frame_free(frame); |
1424 | jermar | 245 | } |
246 | } else { |
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247 | /* |
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2132 | jermar | 248 | * The frame is either anonymous memory or the mixed case (i.e. |
249 | * lower part is backed by the ELF image and the upper is |
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250 | * anonymous). In any case, a frame needs to be freed. |
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2134 | jermar | 251 | */ |
252 | frame_free(frame); |
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1424 | jermar | 253 | } |
254 | } |
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1426 | jermar | 255 | |
256 | /** Share ELF image backed address space area. |
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257 | * |
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258 | * If the area is writable, then all mapped pages are duplicated in the pagemap. |
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259 | * Otherwise only portions of the area that are not backed by the ELF image |
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260 | * are put into the pagemap. |
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261 | * |
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262 | * The address space and address space area must be locked prior to the call. |
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263 | * |
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264 | * @param area Address space area. |
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265 | */ |
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266 | void elf_share(as_area_t *area) |
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267 | { |
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268 | elf_segment_header_t *entry = area->backend_data.segment; |
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269 | link_t *cur; |
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270 | btree_node_t *leaf, *node; |
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1780 | jermar | 271 | uintptr_t start_anon = entry->p_vaddr + entry->p_filesz; |
1426 | jermar | 272 | |
273 | /* |
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274 | * Find the node in which to start linear search. |
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275 | */ |
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276 | if (area->flags & AS_AREA_WRITE) { |
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2132 | jermar | 277 | node = list_get_instance(area->used_space.leaf_head.next, |
278 | btree_node_t, leaf_link); |
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1426 | jermar | 279 | } else { |
280 | (void) btree_search(&area->sh_info->pagemap, start_anon, &leaf); |
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2132 | jermar | 281 | node = btree_leaf_node_left_neighbour(&area->sh_info->pagemap, |
282 | leaf); |
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1426 | jermar | 283 | if (!node) |
284 | node = leaf; |
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285 | } |
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286 | |||
287 | /* |
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288 | * Copy used anonymous portions of the area to sh_info's page map. |
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289 | */ |
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290 | mutex_lock(&area->sh_info->lock); |
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2132 | jermar | 291 | for (cur = &node->leaf_link; cur != &area->used_space.leaf_head; |
292 | cur = cur->next) { |
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1426 | jermar | 293 | int i; |
294 | |||
295 | node = list_get_instance(cur, btree_node_t, leaf_link); |
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296 | |||
297 | for (i = 0; i < node->keys; i++) { |
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1780 | jermar | 298 | uintptr_t base = node->key[i]; |
1426 | jermar | 299 | count_t count = (count_t) node->value[i]; |
300 | int j; |
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301 | |||
302 | /* |
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303 | * Skip read-only areas of used space that are backed |
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304 | * by the ELF image. |
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305 | */ |
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306 | if (!(area->flags & AS_AREA_WRITE)) |
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307 | if (base + count*PAGE_SIZE <= start_anon) |
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308 | continue; |
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309 | |||
310 | for (j = 0; j < count; j++) { |
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311 | pte_t *pte; |
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312 | |||
313 | /* |
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2132 | jermar | 314 | * Skip read-only pages that are backed by the |
315 | * ELF image. |
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1426 | jermar | 316 | */ |
317 | if (!(area->flags & AS_AREA_WRITE)) |
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2132 | jermar | 318 | if (base + (j + 1) * PAGE_SIZE <= |
319 | start_anon) |
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1426 | jermar | 320 | continue; |
321 | |||
322 | page_table_lock(area->as, false); |
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2132 | jermar | 323 | pte = page_mapping_find(area->as, |
324 | base + j * PAGE_SIZE); |
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325 | ASSERT(pte && PTE_VALID(pte) && |
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326 | PTE_PRESENT(pte)); |
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327 | btree_insert(&area->sh_info->pagemap, |
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328 | (base + j * PAGE_SIZE) - area->base, |
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2467 | jermar | 329 | (void *) PTE_GET_FRAME(pte), NULL); |
1426 | jermar | 330 | page_table_unlock(area->as, false); |
2132 | jermar | 331 | |
332 | pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(pte)); |
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333 | frame_reference_add(pfn); |
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1426 | jermar | 334 | } |
335 | |||
336 | } |
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337 | } |
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338 | mutex_unlock(&area->sh_info->lock); |
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339 | } |
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1702 | cejka | 340 | |
1757 | jermar | 341 | /** @} |
1702 | cejka | 342 | */ |