-/* Copyright (c) 2007-2019. The SimGrid Team. All rights reserved. */
+/* Copyright (c) 2007-2023. The SimGrid Team. All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
-#include "src/mc/ModelChecker.hpp"
+#include "src/mc/sosp/Region.hpp"
#include "src/mc/mc_config.hpp"
#include "src/mc/mc_forward.hpp"
-
-#include "src/mc/mc_smx.hpp"
-#include "src/mc/sosp/Region.hpp"
+#include "src/mc/sosp/RemoteProcessMemory.hpp"
#include <cstdlib>
#include <sys/mman.h>
#define MAP_POPULATE MAP_PREFAULT_READ
#endif
-XBT_LOG_NEW_DEFAULT_SUBCATEGORY(mc_RegionSnaphot, mc, "Logging specific to region snapshots");
-
-namespace simgrid {
-namespace mc {
+namespace simgrid::mc {
-RegionSnapshot::RegionSnapshot(RegionType region_type, void* start_addr, size_t size)
+Region::Region(PageStore& store, const RemoteProcessMemory& memory, RegionType region_type, void* start_addr,
+ size_t size)
: region_type_(region_type), start_addr_(start_addr), size_(size)
{
- simgrid::mc::RemoteClient* process = &mc_model_checker->process();
-
xbt_assert((((uintptr_t)start_addr) & (xbt_pagesize - 1)) == 0, "Start address not at the beginning of a page");
- chunks_ = ChunkedData(mc_model_checker->page_store(), *process, RemotePtr<void>(start_addr), mmu::chunk_count(size));
+ chunks_ = ChunkedData(store, memory, RemotePtr<void>(start_addr), mmu::chunk_count(size));
}
/** @brief Restore a region from a snapshot
*
* @param region Target region
*/
-void RegionSnapshot::restore()
+void Region::restore(const RemoteProcessMemory& memory) const
{
xbt_assert(((start().address()) & (xbt_pagesize - 1)) == 0, "Not at the beginning of a page");
xbt_assert(simgrid::mc::mmu::chunk_count(size()) == get_chunks().page_count());
for (size_t i = 0; i != get_chunks().page_count(); ++i) {
- void* target_page = (void*)simgrid::mc::mmu::join(i, (std::uintptr_t)(void*)start().address());
+ auto* target_page = (void*)simgrid::mc::mmu::join(i, (std::uintptr_t)(void*)start().address());
const void* source_page = get_chunks().page(i);
- mc_model_checker->process().write_bytes(source_page, xbt_pagesize, remote(target_page));
+ memory.write_bytes(source_page, xbt_pagesize, remote(target_page));
+ }
+}
+
+static XBT_ALWAYS_INLINE void* mc_translate_address_region(uintptr_t addr, const simgrid::mc::Region* region)
+{
+ auto [pageno, offset] = simgrid::mc::mmu::split(addr - region->start().address());
+ void* snapshot_page = region->get_chunks().page(pageno);
+ return (char*)snapshot_page + offset;
+}
+
+void* Region::read(void* target, const void* addr, std::size_t size) const
+{
+ xbt_assert(contain(simgrid::mc::remote(addr)), "Trying to read out of the region boundary.");
+
+ // Last byte of the region:
+ const void* end_addr = (const char*)addr + size - 1;
+ if (simgrid::mc::mmu::same_chunk((std::uintptr_t)addr, (std::uintptr_t)end_addr)) {
+ // The memory is contained in a single page:
+ return mc_translate_address_region((uintptr_t)addr, this);
}
+ // Otherwise, the memory spans several pages. Let's copy it all into the provided buffer
+ xbt_assert(target != nullptr, "Missing destination buffer for fragmented memory access");
+
+ // TODO, we assume the chunks are aligned to natural chunk boundaries.
+ // We should remove this assumption.
+
+ // Page of the last byte of the memory area:
+ size_t page_end = simgrid::mc::mmu::split((std::uintptr_t)end_addr).first;
+
+ void* dest = target; // iterator in the buffer to where we should copy next
+
+ // Read each page:
+ while (simgrid::mc::mmu::split((std::uintptr_t)addr).first != page_end) {
+ const void* snapshot_addr = mc_translate_address_region((uintptr_t)addr, this);
+ auto* next_page = (void*)simgrid::mc::mmu::join(simgrid::mc::mmu::split((std::uintptr_t)addr).first + 1, 0);
+ size_t readable = (char*)next_page - (const char*)addr;
+ memcpy(dest, snapshot_addr, readable);
+ addr = (const char*)addr + readable;
+ dest = (char*)dest + readable;
+ size -= readable;
+ }
+
+ // Read the end:
+ const void* snapshot_addr = mc_translate_address_region((uintptr_t)addr, this);
+ memcpy(dest, snapshot_addr, size);
+
+ return target;
}
-} // namespace mc
-} // namespace simgrid
+} // namespace simgrid::mc
+
+/** Compare memory between snapshots (with known regions)
+ *
+ * @param addr1 Address in the first snapshot
+ * @param region1 Region of the address in the first snapshot
+ * @param addr2 Address in the second snapshot
+ * @param region2 Region of the address in the second snapshot
+ * @return same semantic as memcmp
+ */
+int MC_snapshot_region_memcmp(const void* addr1, const simgrid::mc::Region* region1, const void* addr2,
+ const simgrid::mc::Region* region2, size_t size)
+{
+ // Using alloca() for large allocations may trigger stack overflow:
+ // use malloc if the buffer is too big.
+ bool stack_alloc = size < 64;
+ void* buffer1a = stack_alloc ? alloca(size) : ::operator new(size);
+ void* buffer2a = stack_alloc ? alloca(size) : ::operator new(size);
+ const void* buffer1 = region1->read(buffer1a, addr1, size);
+ const void* buffer2 = region2->read(buffer2a, addr2, size);
+ int res;
+ if (buffer1 == buffer2)
+ res = 0;
+ else
+ res = memcmp(buffer1, buffer2, size);
+ if (not stack_alloc) {
+ ::operator delete(buffer1a);
+ ::operator delete(buffer2a);
+ }
+ return res;
+}
