1 /* Copyright (c) 2007-2020. 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
22 Region::Region(RegionType region_type, void* start_addr, size_t size)
23 : region_type_(region_type), start_addr_(start_addr), size_(size)
25 xbt_assert((((uintptr_t)start_addr) & (xbt_pagesize - 1)) == 0, "Start address not at the beginning of a page");
27 chunks_ = ChunkedData(mc_model_checker->page_store(), mc_model_checker->get_remote_simulation(),
28 RemotePtr<void>(start_addr), mmu::chunk_count(size));
31 /** @brief Restore a region from a snapshot
33 * @param region Target region
35 void Region::restore() const
37 xbt_assert(((start().address()) & (xbt_pagesize - 1)) == 0, "Not at the beginning of a page");
38 xbt_assert(simgrid::mc::mmu::chunk_count(size()) == get_chunks().page_count());
40 for (size_t i = 0; i != get_chunks().page_count(); ++i) {
41 void* target_page = (void*)simgrid::mc::mmu::join(i, (std::uintptr_t)(void*)start().address());
42 const void* source_page = get_chunks().page(i);
43 mc_model_checker->get_remote_simulation().write_bytes(source_page, xbt_pagesize, remote(target_page));
47 static XBT_ALWAYS_INLINE void* mc_translate_address_region(uintptr_t addr, const simgrid::mc::Region* region)
49 auto split = simgrid::mc::mmu::split(addr - region->start().address());
50 auto pageno = split.first;
51 auto offset = split.second;
52 void* snapshot_page = region->get_chunks().page(pageno);
53 return (char*)snapshot_page + offset;
56 void* Region::read(void* target, const void* addr, std::size_t size) const
58 xbt_assert(contain(simgrid::mc::remote(addr)), "Trying to read out of the region boundary.");
60 // Last byte of the region:
61 const void* end = (const char*)addr + size - 1;
62 if (simgrid::mc::mmu::same_chunk((std::uintptr_t)addr, (std::uintptr_t)end)) {
63 // The memory is contained in a single page:
64 return mc_translate_address_region((uintptr_t)addr, this);
66 // Otherwise, the memory spans several pages. Let's copy it all into the provided buffer
67 xbt_assert(target != nullptr, "Missing destination buffer for fragmented memory access");
69 // TODO, we assume the chunks are aligned to natural chunk boundaries.
70 // We should remove this assumption.
72 // Page of the last byte of the memory area:
73 size_t page_end = simgrid::mc::mmu::split((std::uintptr_t)end).first;
75 void* dest = target; // iterator in the buffer to where we should copy next
78 while (simgrid::mc::mmu::split((std::uintptr_t)addr).first != page_end) {
79 const void* snapshot_addr = mc_translate_address_region((uintptr_t)addr, this);
80 void* next_page = (void*)simgrid::mc::mmu::join(simgrid::mc::mmu::split((std::uintptr_t)addr).first + 1, 0);
81 size_t readable = (char*)next_page - (const char*)addr;
82 memcpy(dest, snapshot_addr, readable);
83 addr = (const char*)addr + readable;
84 dest = (char*)dest + readable;
89 const void* snapshot_addr = mc_translate_address_region((uintptr_t)addr, this);
90 memcpy(dest, snapshot_addr, size);
96 } // namespace simgrid
98 /** Compare memory between snapshots (with known regions)
100 * @param addr1 Address in the first snapshot
101 * @param region1 Region of the address in the first snapshot
102 * @param addr2 Address in the second snapshot
103 * @param region2 Region of the address in the second snapshot
104 * @return same semantic as memcmp
106 int MC_snapshot_region_memcmp(const void* addr1, const simgrid::mc::Region* region1, const void* addr2,
107 const simgrid::mc::Region* region2, size_t size)
109 // Using alloca() for large allocations may trigger stack overflow:
110 // use malloc if the buffer is too big.
111 bool stack_alloc = size < 64;
112 void* buffer1a = stack_alloc ? alloca(size) : ::operator new(size);
113 void* buffer2a = stack_alloc ? alloca(size) : ::operator new(size);
114 const void* buffer1 = region1->read(buffer1a, addr1, size);
115 const void* buffer2 = region2->read(buffer2a, addr2, size);
117 if (buffer1 == buffer2)
120 res = memcmp(buffer1, buffer2, size);
121 if (not stack_alloc) {
122 ::operator delete(buffer1a);
123 ::operator delete(buffer2a);