1 /* Copyright (c) 2014. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
7 #include "mc_private.h"
10 mc_mem_region_t mc_get_snapshot_region(void* addr, mc_snapshot_t snapshot)
12 for (size_t i = 0; i != NB_REGIONS; ++i) {
13 mc_mem_region_t region = snapshot->regions[i];
14 void* start = region->start_addr;
15 void* end = (char*) start + region->size;
17 if (addr >= start && addr < end) {
25 void* mc_translate_address_region(uintptr_t addr, mc_mem_region_t region)
32 else if (region->data) {
33 uintptr_t offset = addr - (uintptr_t) region->start_addr;
34 return (void *) ((uintptr_t) region->data + offset);
38 else if (region->page_numbers) {
39 size_t pageno = mc_page_number(region->data, (void*) addr);
40 return (char*) region->page_numbers[pageno] + mc_page_offset((void*) addr);
44 xbt_die("No data for this memory region");
48 void* mc_translate_address(uintptr_t addr, mc_snapshot_t snapshot)
51 // If not in a process state/clone:
53 return (uintptr_t *) addr;
56 mc_mem_region_t region = mc_get_snapshot_region((void*) addr, snapshot);
57 return mc_translate_address_region(addr, region);
61 /** @brief Read memory from a snapshot region broken across fragmented pages
63 * @param addr Process (non-snapshot) address of the data
64 * @param region Snapshot memory region where the data is located
65 * @param target Buffer to store the value
66 * @param size Size of the data to read in bytes
67 * @return Pointer where the data is located (target buffer of original location)
69 static void* mc_snapshot_read_fragmented(void* addr, mc_mem_region_t region, void* target, size_t size)
71 void* end = (char*) addr + size - 1;
72 size_t page_end = mc_page_number(NULL, end);
75 while (mc_page_number(NULL, addr) != page_end) {
76 void* snapshot_addr = mc_translate_address_region((uintptr_t) addr, region);
77 void* next_page = mc_page_from_number(NULL, mc_page_number(NULL, addr) + 1);
78 size_t readable = (char*) next_page - (char*) addr;
79 memcpy(target, snapshot_addr, readable);
80 target = (char*) target + readable;
85 void* snapshot_addr = mc_translate_address_region((uintptr_t)addr, region);
86 memcpy(target, snapshot_addr, size);
91 /** @brief Read memory from a snapshot region
93 * @param addr Process (non-snapshot) address of the data
94 * @param region Snapshot memory region where the data is located
95 * @param target Buffer to store the value
96 * @param size Size of the data to read in bytes
97 * @return Pointer where the data is located (target buffer of original location)
99 void* mc_snapshot_read_region(void* addr, mc_mem_region_t region, void* target, size_t size)
101 uintptr_t offset = (uintptr_t) addr - (uintptr_t) region->start_addr;
103 if (addr < region->start_addr || (char*) addr+size >= (char*)region->start_addr+region->size) {
104 xbt_die("Trying to read out of the region boundary.");
107 // Linear memory region:
109 return (void*) ((uintptr_t) region->data + offset);
112 // Fragmented memory region:
113 else if (region->page_numbers) {
114 void* end = (char*) addr + size - 1;
115 if( mc_same_page(addr, end) ) {
116 // The memory is contained in a single page:
117 return mc_translate_address_region((uintptr_t) addr, region);
119 // The memory spans several pages:
120 return mc_snapshot_read_fragmented(addr, region, target, size);
125 xbt_die("No data available for this region");
129 /** @brief Read memory from a snapshot
131 * @param addr Process (non-snapshot) address of the data
132 * @param snapshot Snapshot (or NULL is no snapshot)
133 * @param target Buffer to store the value
134 * @param size Size of the data to read in bytes
135 * @return Pointer where the data is located (target buffer of original location)
137 void* mc_snapshot_read(void* addr, mc_snapshot_t snapshot, void* target, size_t size)
140 mc_mem_region_t region = mc_get_snapshot_region(addr, snapshot);
141 return mc_snapshot_read_region(addr, region, target, size);
147 int mc_snapshot_memcp(
148 void* addr1, mc_snapshot_t snapshot1,
149 void* addr2, mc_snapshot_t snapshot2, size_t size)
151 void* buffer1 = mc_snapshot_read(addr1, snapshot1, alloca(size), size);
152 void* buffer2 = mc_snapshot_read(addr2, snapshot2, alloca(size), size);
153 if (buffer1 == buffer2) {
156 return memcmp(buffer1, buffer2, size);