shim_brk.c 7.0 KB

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  1. /* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */
  2. /* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */
  3. /* Copyright (C) 2014 Stony Brook University
  4. This file is part of Graphene Library OS.
  5. Graphene Library OS is free software: you can redistribute it and/or
  6. modify it under the terms of the GNU Lesser General Public License
  7. as published by the Free Software Foundation, either version 3 of the
  8. License, or (at your option) any later version.
  9. Graphene Library OS is distributed in the hope that it will be useful,
  10. but WITHOUT ANY WARRANTY; without even the implied warranty of
  11. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12. GNU Lesser General Public License for more details.
  13. You should have received a copy of the GNU Lesser General Public License
  14. along with this program. If not, see <http://www.gnu.org/licenses/>. */
  15. /*
  16. * shim_brk.c
  17. *
  18. * Implementation of system call "brk".
  19. */
  20. #include <shim_internal.h>
  21. #include <shim_utils.h>
  22. #include <shim_table.h>
  23. #include <shim_vma.h>
  24. #include <shim_checkpoint.h>
  25. #include <shim_profile.h>
  26. #include <pal.h>
  27. #include <sys/mman.h>
  28. #define BRK_SIZE 4096
  29. unsigned long brk_max_size = 0;
  30. struct shim_brk_info {
  31. void * brk_start;
  32. void * brk_end;
  33. void * brk_current;
  34. };
  35. static struct shim_brk_info region;
  36. DEFINE_PROFILE_OCCURENCE(brk, memory);
  37. DEFINE_PROFILE_OCCURENCE(brk_count, memory);
  38. DEFINE_PROFILE_OCCURENCE(brk_migrate_count, memory);
  39. void get_brk_region (void ** start, void ** end, void ** current)
  40. {
  41. master_lock();
  42. *start = region.brk_start;
  43. *end = region.brk_end;
  44. *current = region.brk_current;
  45. master_unlock();
  46. }
  47. int init_brk_region (void * brk_region)
  48. {
  49. if (region.brk_start)
  50. return 0;
  51. if (!brk_max_size) {
  52. char brk_cfg[CONFIG_MAX];
  53. if (root_config &&
  54. get_config(root_config, "sys.brk.size", brk_cfg, CONFIG_MAX) > 0)
  55. brk_max_size = parse_int(brk_cfg);
  56. if (!brk_max_size)
  57. brk_max_size = DEFAULT_BRK_MAX_SIZE;
  58. }
  59. /*
  60. * Chia-Che 8/24/2017
  61. * Adding an argument to specify the initial starting
  62. * address of brk region.
  63. * The general assumption of Linux is that the brk region
  64. * should be within [exec-data-end, exec-data-end + 0x2000000)
  65. */
  66. if (brk_region) {
  67. while (true) {
  68. uint32_t rand;
  69. getrand(&rand, sizeof(rand));
  70. rand %= 0x2000000;
  71. rand = ALIGN_UP(rand);
  72. struct shim_vma * vma;
  73. if (lookup_overlap_vma(brk_region + rand, brk_max_size, &vma)
  74. == -ENOENT) {
  75. brk_region += rand;
  76. break;
  77. }
  78. brk_region = vma->addr + vma->length;
  79. put_vma(vma);
  80. }
  81. } else {
  82. brk_region = get_unmapped_vma(brk_max_size,
  83. MAP_PRIVATE|MAP_ANONYMOUS);
  84. if (!brk_region)
  85. return -ENOMEM;
  86. }
  87. void * end_brk_region = NULL;
  88. // brk region assigned
  89. brk_region = (void *) DkVirtualMemoryAlloc(brk_region, brk_max_size, 0,
  90. PAL_PROT_READ|PAL_PROT_WRITE);
  91. if (!brk_region)
  92. return -ENOMEM;
  93. ADD_PROFILE_OCCURENCE(brk, brk_max_size);
  94. INC_PROFILE_OCCURENCE(brk_count);
  95. end_brk_region = brk_region + BRK_SIZE;
  96. region.brk_start = brk_region;
  97. region.brk_end = end_brk_region;
  98. region.brk_current = brk_region;
  99. debug("brk area: %p - %p\n", brk_region, end_brk_region);
  100. debug("brk reserved area: %p - %p\n", end_brk_region,
  101. brk_region + brk_max_size);
  102. bkeep_mmap(brk_region, BRK_SIZE, PROT_READ|PROT_WRITE,
  103. MAP_ANONYMOUS|MAP_PRIVATE, NULL, 0, "[heap]");
  104. bkeep_mmap(end_brk_region, brk_max_size - BRK_SIZE,
  105. PROT_READ|PROT_WRITE,
  106. MAP_ANONYMOUS|MAP_PRIVATE|VMA_UNMAPPED,
  107. NULL, 0, NULL);
  108. return 0;
  109. }
  110. int reset_brk (void)
  111. {
  112. master_lock();
  113. if (!region.brk_start) {
  114. master_unlock();
  115. return 0;
  116. }
  117. int ret = shim_do_munmap(region.brk_start,
  118. region.brk_end - region.brk_start);
  119. if (ret < 0) {
  120. master_unlock();
  121. return ret;
  122. }
  123. region.brk_start = region.brk_end = region.brk_current = NULL;
  124. master_unlock();
  125. return 0;
  126. }
  127. void * shim_do_brk (void * brk)
  128. {
  129. master_lock();
  130. init_brk_region(NULL);
  131. if (!brk) {
  132. unchanged:
  133. brk = region.brk_current;
  134. goto out;
  135. }
  136. if (brk < region.brk_start)
  137. goto unchanged;
  138. if (brk > region.brk_end) {
  139. if (brk > region.brk_start + brk_max_size)
  140. goto unchanged;
  141. void * brk_end = region.brk_end;
  142. while (brk_end < brk)
  143. brk_end += BRK_SIZE;
  144. debug("brk area: %p - %p\n", region.brk_start, brk_end);
  145. debug("brk reserved area: %p - %p\n", brk_end,
  146. region.brk_start + brk_max_size);
  147. bkeep_mmap(region.brk_start, brk_end - region.brk_start,
  148. PROT_READ|PROT_WRITE,
  149. MAP_ANONYMOUS|MAP_PRIVATE, NULL, 0, "heap");
  150. region.brk_current = brk;
  151. region.brk_end = brk_end;
  152. goto out;
  153. }
  154. region.brk_current = brk;
  155. out:
  156. master_unlock();
  157. return brk;
  158. }
  159. BEGIN_CP_FUNC(brk)
  160. {
  161. if (region.brk_start) {
  162. ADD_CP_FUNC_ENTRY(region.brk_start);
  163. ADD_CP_ENTRY(ADDR, region.brk_current);
  164. ADD_CP_ENTRY(SIZE, region.brk_end - region.brk_start);
  165. assert(brk_max_size);
  166. ADD_CP_ENTRY(SIZE, brk_max_size);
  167. }
  168. }
  169. END_CP_FUNC(bek)
  170. BEGIN_RS_FUNC(brk)
  171. {
  172. region.brk_start = (void *) GET_CP_FUNC_ENTRY();
  173. region.brk_current = (void *) GET_CP_ENTRY(ADDR);
  174. region.brk_end = region.brk_start + GET_CP_ENTRY(SIZE);
  175. brk_max_size = GET_CP_ENTRY(SIZE);
  176. debug("brk area: %p - %p\n", region.brk_start, region.brk_end);
  177. unsigned long brk_size = region.brk_end - region.brk_start;
  178. if (brk_size < brk_max_size) {
  179. void * brk_region = (void *) DkVirtualMemoryAlloc(region.brk_end,
  180. brk_max_size - brk_size, 0,
  181. PAL_PROT_READ|PAL_PROT_WRITE);
  182. if (brk_region != region.brk_end)
  183. return -EACCES;
  184. ADD_PROFILE_OCCURENCE(brk, brk_max_size - brk_size);
  185. INC_PROFILE_OCCURENCE(brk_migrate_count);
  186. debug("brk reserved area: %p - %p\n", region.brk_end,
  187. region.brk_start + brk_max_size);
  188. bkeep_mmap(region.brk_end, brk_max_size - brk_size,
  189. PROT_READ|PROT_WRITE,
  190. MAP_ANONYMOUS|MAP_PRIVATE|VMA_UNMAPPED, NULL, 0,
  191. NULL);
  192. }
  193. DEBUG_RS("current=%p,region=%p-%p", region.brk_current, region.brk_start,
  194. region.brk_end);
  195. }
  196. END_RS_FUNC(brk)