1 /* Copyright (c) 2007-2019. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #include "src/mc/ModelChecker.hpp"
7 #include "src/mc/mc_config.hpp"
8 #include "src/mc/mc_forward.hpp"
10 #include "src/mc/mc_smx.hpp"
11 #include "src/mc/sosp/Region.hpp"
16 #define MAP_POPULATE MAP_PREFAULT_READ
19 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_RegionSnaphot, mc, "Logging specific to region snapshots");
24 Region::Region(RegionType region_type, void* start_addr, size_t size)
25 : region_type_(region_type), start_addr_(start_addr), size_(size)
27 xbt_assert((((uintptr_t)start_addr) & (xbt_pagesize - 1)) == 0, "Start address not at the beginning of a page");
29 chunks_ = ChunkedData(mc_model_checker->page_store(), mc_model_checker->process(), RemotePtr<void>(start_addr),
30 mmu::chunk_count(size));
33 /** @brief Restore a region from a snapshot
35 * @param region Target region
37 void Region::restore()
39 xbt_assert(((start().address()) & (xbt_pagesize - 1)) == 0, "Not at the beginning of a page");
40 xbt_assert(simgrid::mc::mmu::chunk_count(size()) == get_chunks().page_count());
42 for (size_t i = 0; i != get_chunks().page_count(); ++i) {
43 void* target_page = (void*)simgrid::mc::mmu::join(i, (std::uintptr_t)(void*)start().address());
44 const void* source_page = get_chunks().page(i);
45 mc_model_checker->process().write_bytes(source_page, xbt_pagesize, remote(target_page));
49 static XBT_ALWAYS_INLINE void* mc_translate_address_region(uintptr_t addr, simgrid::mc::Region* region)
51 auto split = simgrid::mc::mmu::split(addr - region->start().address());
52 auto pageno = split.first;
53 auto offset = split.second;
54 const void* snapshot_page = region->get_chunks().page(pageno);
55 return (char*)snapshot_page + offset;
58 void* Region::read(void* target, const void* addr, std::size_t size)
60 xbt_assert(contain(simgrid::mc::remote(addr)), "Trying to read out of the region boundary.");
62 // Last byte of the region:
63 void* end = (char*)addr + size - 1;
64 if (simgrid::mc::mmu::same_chunk((std::uintptr_t)addr, (std::uintptr_t)end)) {
65 // The memory is contained in a single page:
66 return mc_translate_address_region((uintptr_t)addr, this);
68 // Otherwise, the memory spans several pages. Let's copy it all into the provided buffer
69 xbt_assert(target != nullptr, "Missing destination buffer for fragmented memory access");
71 // TODO, we assume the chunks are aligned to natural chunk boundaries.
72 // We should remove this assumption.
74 // Page of the last byte of the memory area:
75 size_t page_end = simgrid::mc::mmu::split((std::uintptr_t)end).first;
77 void* dest = target; // iterator in the buffer to where we should copy next
80 while (simgrid::mc::mmu::split((std::uintptr_t)addr).first != page_end) {
81 void* snapshot_addr = mc_translate_address_region((uintptr_t)addr, this);
82 void* next_page = (void*)simgrid::mc::mmu::join(simgrid::mc::mmu::split((std::uintptr_t)addr).first + 1, 0);
83 size_t readable = (char*)next_page - (char*)addr;
84 memcpy(dest, snapshot_addr, readable);
85 addr = (char*)addr + readable;
86 dest = (char*)dest + readable;
91 void* snapshot_addr = mc_translate_address_region((uintptr_t)addr, this);
92 memcpy(dest, snapshot_addr, size);
98 } // namespace simgrid
100 /** Compare memory between snapshots (with known regions)
102 * @param addr1 Address in the first snapshot
103 * @param region1 Region of the address in the first snapshot
104 * @param addr2 Address in the second snapshot
105 * @param region2 Region of the address in the second snapshot
106 * @return same semantic as memcmp
108 int MC_snapshot_region_memcmp(const void* addr1, simgrid::mc::Region* region1, const void* addr2,
109 simgrid::mc::Region* region2, size_t size)
111 // Using alloca() for large allocations may trigger stack overflow:
112 // use malloc if the buffer is too big.
113 bool stack_alloc = size < 64;
114 void* buffer1a = stack_alloc ? alloca(size) : ::operator new(size);
115 void* buffer2a = stack_alloc ? alloca(size) : ::operator new(size);
116 const void* buffer1 = region1->read(buffer1a, addr1, size);
117 const void* buffer2 = region2->read(buffer2a, addr2, size);
119 if (buffer1 == buffer2)
122 res = memcmp(buffer1, buffer2, size);
123 if (not stack_alloc) {
124 ::operator delete(buffer1a);
125 ::operator delete(buffer2a);