lldb/source/Target/Memory.cpp

   1 //===-- Memory.cpp --------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "lldb/Target/Memory.h"
  10 #include "lldb/Target/Process.h"
  11 #include "lldb/Utility/DataBufferHeap.h"
  12 #include "lldb/Utility/Log.h"
  13 #include "lldb/Utility/RangeMap.h"
  14 #include "lldb/Utility/State.h"
  15
  16 #include <cinttypes>
  17 #include <memory>
  18
  19 using namespace lldb;
  20 using namespace lldb_private;
  21
  22 // MemoryCache constructor
  23 MemoryCache::MemoryCache(Process &process)
  24     : m_mutex(), m_L1_cache(), m_L2_cache(), m_invalid_ranges(),
  25       m_process(process),
  26       m_L2_cache_line_byte_size(process.GetMemoryCacheLineSize()) {}
  27
  28 // Destructor
  29 MemoryCache::~MemoryCache() = default;
  30
  31 void MemoryCache::Clear(bool clear_invalid_ranges) {
  32   std::lock_guard<std::recursive_mutex> guard(m_mutex);
  33   m_L1_cache.clear();
  34   m_L2_cache.clear();
  35   if (clear_invalid_ranges)
  36     m_invalid_ranges.Clear();
  37   m_L2_cache_line_byte_size = m_process.GetMemoryCacheLineSize();
  38 }
  39
  40 void MemoryCache::AddL1CacheData(lldb::addr_t addr, const void *src,
  41                                  size_t src_len) {
  42   AddL1CacheData(
  43       addr, DataBufferSP(new DataBufferHeap(DataBufferHeap(src, src_len))));
  44 }
  45
  46 void MemoryCache::AddL1CacheData(lldb::addr_t addr,
  47                                  const DataBufferSP &data_buffer_sp) {
  48   std::lock_guard<std::recursive_mutex> guard(m_mutex);
  49   m_L1_cache[addr] = data_buffer_sp;
  50 }
  51
  52 void MemoryCache::Flush(addr_t addr, size_t size) {
  53   if (size == 0)
  54     return;
  55
  56   std::lock_guard<std::recursive_mutex> guard(m_mutex);
  57
  58   // Erase any blocks from the L1 cache that intersect with the flush range
  59   if (!m_L1_cache.empty()) {
  60     AddrRange flush_range(addr, size);
  61     BlockMap::iterator pos = m_L1_cache.upper_bound(addr);
  62     if (pos != m_L1_cache.begin()) {
  63       --pos;
  64     }
  65     while (pos != m_L1_cache.end()) {
  66       AddrRange chunk_range(pos->first, pos->second->GetByteSize());
  67       if (!chunk_range.DoesIntersect(flush_range))
  68         break;
  69       pos = m_L1_cache.erase(pos);
  70     }
  71   }
  72
  73   if (!m_L2_cache.empty()) {
  74     const uint32_t cache_line_byte_size = m_L2_cache_line_byte_size;
  75     const addr_t end_addr = (addr + size - 1);
  76     const addr_t first_cache_line_addr = addr - (addr % cache_line_byte_size);
  77     const addr_t last_cache_line_addr =
  78         end_addr - (end_addr % cache_line_byte_size);
  79     // Watch for overflow where size will cause us to go off the end of the
  80     // 64 bit address space
  81     uint32_t num_cache_lines;
  82     if (last_cache_line_addr >= first_cache_line_addr)
  83       num_cache_lines = ((last_cache_line_addr - first_cache_line_addr) /
  84                          cache_line_byte_size) +
  85                         1;
  86     else
  87       num_cache_lines =
  88           (UINT64_MAX - first_cache_line_addr + 1) / cache_line_byte_size;
  89
  90     uint32_t cache_idx = 0;
  91     for (addr_t curr_addr = first_cache_line_addr; cache_idx < num_cache_lines;
  92          curr_addr += cache_line_byte_size, ++cache_idx) {
  93       BlockMap::iterator pos = m_L2_cache.find(curr_addr);
  94       if (pos != m_L2_cache.end())
  95         m_L2_cache.erase(pos);
  96     }
  97   }
  98 }
  99
 100 void MemoryCache::AddInvalidRange(lldb::addr_t base_addr,
 101                                   lldb::addr_t byte_size) {
 102   if (byte_size > 0) {
 103     std::lock_guard<std::recursive_mutex> guard(m_mutex);
 104     InvalidRanges::Entry range(base_addr, byte_size);
 105     m_invalid_ranges.Append(range);
 106     m_invalid_ranges.Sort();
 107   }
 108 }
 109
 110 bool MemoryCache::RemoveInvalidRange(lldb::addr_t base_addr,
 111                                      lldb::addr_t byte_size) {
 112   if (byte_size > 0) {
 113     std::lock_guard<std::recursive_mutex> guard(m_mutex);
 114     const uint32_t idx = m_invalid_ranges.FindEntryIndexThatContains(base_addr);
 115     if (idx != UINT32_MAX) {
 116       const InvalidRanges::Entry *entry = m_invalid_ranges.GetEntryAtIndex(idx);
 117       if (entry->GetRangeBase() == base_addr &&
 118           entry->GetByteSize() == byte_size)
 119         return m_invalid_ranges.RemoveEntryAtIndex(idx);
 120     }
 121   }
 122   return false;
 123 }
 124
 125 size_t MemoryCache::Read(addr_t addr, void *dst, size_t dst_len,
 126                          Status &error) {
 127   size_t bytes_left = dst_len;
 128
 129   // Check the L1 cache for a range that contain the entire memory read. If we
 130   // find a range in the L1 cache that does, we use it. Else we fall back to
 131   // reading memory in m_L2_cache_line_byte_size byte sized chunks. The L1
 132   // cache contains chunks of memory that are not required to be
 133   // m_L2_cache_line_byte_size bytes in size, so we don't try anything tricky
 134   // when reading from them (no partial reads from the L1 cache).
 135
 136   std::lock_guard<std::recursive_mutex> guard(m_mutex);
 137   if (!m_L1_cache.empty()) {
 138     AddrRange read_range(addr, dst_len);
 139     BlockMap::iterator pos = m_L1_cache.upper_bound(addr);
 140     if (pos != m_L1_cache.begin()) {
 141       --pos;
 142     }
 143     AddrRange chunk_range(pos->first, pos->second->GetByteSize());
 144     if (chunk_range.Contains(read_range)) {
 145       memcpy(dst, pos->second->GetBytes() + (addr - chunk_range.GetRangeBase()),
 146              dst_len);
 147       return dst_len;
 148     }
 149   }
 150
 151   // If this memory read request is larger than the cache line size, then we
 152   // (1) try to read as much of it at once as possible, and (2) don't add the
 153   // data to the memory cache.  We don't want to split a big read up into more
 154   // separate reads than necessary, and with a large memory read request, it is
 155   // unlikely that the caller function will ask for the next
 156   // 4 bytes after the large memory read - so there's little benefit to saving
 157   // it in the cache.
 158   if (dst && dst_len > m_L2_cache_line_byte_size) {
 159     size_t bytes_read =
 160         m_process.ReadMemoryFromInferior(addr, dst, dst_len, error);
 161     // Add this non block sized range to the L1 cache if we actually read
 162     // anything
 163     if (bytes_read > 0)
 164       AddL1CacheData(addr, dst, bytes_read);
 165     return bytes_read;
 166   }
 167
 168   if (dst && bytes_left > 0) {
 169     const uint32_t cache_line_byte_size = m_L2_cache_line_byte_size;
 170     uint8_t *dst_buf = (uint8_t *)dst;
 171     addr_t curr_addr = addr - (addr % cache_line_byte_size);
 172     addr_t cache_offset = addr - curr_addr;
 173
 174     while (bytes_left > 0) {
 175       if (m_invalid_ranges.FindEntryThatContains(curr_addr)) {
 176         error.SetErrorStringWithFormat("memory read failed for 0x%" PRIx64,
 177                                        curr_addr);
 178         return dst_len - bytes_left;
 179       }
 180
 181       BlockMap::const_iterator pos = m_L2_cache.find(curr_addr);
 182       BlockMap::const_iterator end = m_L2_cache.end();
 183
 184       if (pos != end) {
 185         size_t curr_read_size = cache_line_byte_size - cache_offset;
 186         if (curr_read_size > bytes_left)
 187           curr_read_size = bytes_left;
 188
 189         memcpy(dst_buf + dst_len - bytes_left,
 190                pos->second->GetBytes() + cache_offset, curr_read_size);
 191
 192         bytes_left -= curr_read_size;
 193         curr_addr += curr_read_size + cache_offset;
 194         cache_offset = 0;
 195
 196         if (bytes_left > 0) {
 197           // Get sequential cache page hits
 198           for (++pos; (pos != end) && (bytes_left > 0); ++pos) {
 199             assert((curr_addr % cache_line_byte_size) == 0);
 200
 201             if (pos->first != curr_addr)
 202               break;
 203
 204             curr_read_size = pos->second->GetByteSize();
 205             if (curr_read_size > bytes_left)
 206               curr_read_size = bytes_left;
 207
 208             memcpy(dst_buf + dst_len - bytes_left, pos->second->GetBytes(),
 209                    curr_read_size);
 210
 211             bytes_left -= curr_read_size;
 212             curr_addr += curr_read_size;
 213
 214             // We have a cache page that succeeded to read some bytes but not
 215             // an entire page. If this happens, we must cap off how much data
 216             // we are able to read...
 217             if (pos->second->GetByteSize() != cache_line_byte_size)
 218               return dst_len - bytes_left;
 219           }
 220         }
 221       }
 222
 223       // We need to read from the process
 224
 225       if (bytes_left > 0) {
 226         assert((curr_addr % cache_line_byte_size) == 0);
 227         std::unique_ptr<DataBufferHeap> data_buffer_heap_up(
 228             new DataBufferHeap(cache_line_byte_size, 0));
 229         size_t process_bytes_read = m_process.ReadMemoryFromInferior(
 230             curr_addr, data_buffer_heap_up->GetBytes(),
 231             data_buffer_heap_up->GetByteSize(), error);
 232         if (process_bytes_read == 0)
 233           return dst_len - bytes_left;
 234
 235         if (process_bytes_read != cache_line_byte_size) {
 236           if (process_bytes_read < data_buffer_heap_up->GetByteSize()) {
 237             dst_len -= data_buffer_heap_up->GetByteSize() - process_bytes_read;
 238             bytes_left = process_bytes_read;
 239           }
 240           data_buffer_heap_up->SetByteSize(process_bytes_read);
 241         }
 242         m_L2_cache[curr_addr] = DataBufferSP(data_buffer_heap_up.release());
 243         // We have read data and put it into the cache, continue through the
 244         // loop again to get the data out of the cache...
 245       }
 246     }
 247   }
 248
 249   return dst_len - bytes_left;
 250 }
 251
 252 AllocatedBlock::AllocatedBlock(lldb::addr_t addr, uint32_t byte_size,
 253                                uint32_t permissions, uint32_t chunk_size)
 254     : m_range(addr, byte_size), m_permissions(permissions),
 255       m_chunk_size(chunk_size)
 256 {
 257   // The entire address range is free to start with.
 258   m_free_blocks.Append(m_range);
 259   assert(byte_size > chunk_size);
 260 }
 261
 262 AllocatedBlock::~AllocatedBlock() = default;
 263
 264 lldb::addr_t AllocatedBlock::ReserveBlock(uint32_t size) {
 265   // We must return something valid for zero bytes.
 266   if (size == 0)
 267     size = 1;
 268   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
 269
 270   const size_t free_count = m_free_blocks.GetSize();
 271   for (size_t i=0; i<free_count; ++i)
 272   {
 273     auto &free_block = m_free_blocks.GetEntryRef(i);
 274     const lldb::addr_t range_size = free_block.GetByteSize();
 275     if (range_size >= size)
 276     {
 277       // We found a free block that is big enough for our data. Figure out how
 278       // many chunks we will need and calculate the resulting block size we
 279       // will reserve.
 280       addr_t addr = free_block.GetRangeBase();
 281       size_t num_chunks = CalculateChunksNeededForSize(size);
 282       lldb::addr_t block_size = num_chunks * m_chunk_size;
 283       lldb::addr_t bytes_left = range_size - block_size;
 284       if (bytes_left == 0)
 285       {
 286         // The newly allocated block will take all of the bytes in this
 287         // available block, so we can just add it to the allocated ranges and
 288         // remove the range from the free ranges.
 289         m_reserved_blocks.Insert(free_block, false);
 290         m_free_blocks.RemoveEntryAtIndex(i);
 291       }
 292       else
 293       {
 294         // Make the new allocated range and add it to the allocated ranges.
 295         Range<lldb::addr_t, uint32_t> reserved_block(free_block);
 296         reserved_block.SetByteSize(block_size);
 297         // Insert the reserved range and don't combine it with other blocks in
 298         // the reserved blocks list.
 299         m_reserved_blocks.Insert(reserved_block, false);
 300         // Adjust the free range in place since we won't change the sorted
 301         // ordering of the m_free_blocks list.
 302         free_block.SetRangeBase(reserved_block.GetRangeEnd());
 303         free_block.SetByteSize(bytes_left);
 304       }
 305       LLDB_LOGV(log, "({0}) (size = {1} ({1:x})) => {2:x}", this, size, addr);
 306       return addr;
 307     }
 308   }
 309
 310   LLDB_LOGV(log, "({0}) (size = {1} ({1:x})) => {2:x}", this, size,
 311             LLDB_INVALID_ADDRESS);
 312   return LLDB_INVALID_ADDRESS;
 313 }
 314
 315 bool AllocatedBlock::FreeBlock(addr_t addr) {
 316   bool success = false;
 317   auto entry_idx = m_reserved_blocks.FindEntryIndexThatContains(addr);
 318   if (entry_idx != UINT32_MAX)
 319   {
 320     m_free_blocks.Insert(m_reserved_blocks.GetEntryRef(entry_idx), true);
 321     m_reserved_blocks.RemoveEntryAtIndex(entry_idx);
 322     success = true;
 323   }
 324   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
 325   LLDB_LOGV(log, "({0}) (addr = {1:x}) => {2}", this, addr, success);
 326   return success;
 327 }
 328
 329 AllocatedMemoryCache::AllocatedMemoryCache(Process &process)
 330     : m_process(process), m_mutex(), m_memory_map() {}
 331
 332 AllocatedMemoryCache::~AllocatedMemoryCache() = default;
 333
 334 void AllocatedMemoryCache::Clear() {
 335   std::lock_guard<std::recursive_mutex> guard(m_mutex);
 336   if (m_process.IsAlive()) {
 337     PermissionsToBlockMap::iterator pos, end = m_memory_map.end();
 338     for (pos = m_memory_map.begin(); pos != end; ++pos)
 339       m_process.DoDeallocateMemory(pos->second->GetBaseAddress());
 340   }
 341   m_memory_map.clear();
 342 }
 343
 344 AllocatedMemoryCache::AllocatedBlockSP
 345 AllocatedMemoryCache::AllocatePage(uint32_t byte_size, uint32_t permissions,
 346                                    uint32_t chunk_size, Status &error) {
 347   AllocatedBlockSP block_sp;
 348   const size_t page_size = 4096;
 349   const size_t num_pages = (byte_size + page_size - 1) / page_size;
 350   const size_t page_byte_size = num_pages * page_size;
 351
 352   addr_t addr = m_process.DoAllocateMemory(page_byte_size, permissions, error);
 353
 354   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
 355   if (log) {
 356     LLDB_LOGF(log,
 357               "Process::DoAllocateMemory (byte_size = 0x%8.8" PRIx32
 358               ", permissions = %s) => 0x%16.16" PRIx64,
 359               (uint32_t)page_byte_size, GetPermissionsAsCString(permissions),
 360               (uint64_t)addr);
 361   }
 362
 363   if (addr != LLDB_INVALID_ADDRESS) {
 364     block_sp = std::make_shared<AllocatedBlock>(addr, page_byte_size,
 365                                                 permissions, chunk_size);
 366     m_memory_map.insert(std::make_pair(permissions, block_sp));
 367   }
 368   return block_sp;
 369 }
 370
 371 lldb::addr_t AllocatedMemoryCache::AllocateMemory(size_t byte_size,
 372                                                   uint32_t permissions,
 373                                                   Status &error) {
 374   std::lock_guard<std::recursive_mutex> guard(m_mutex);
 375
 376   addr_t addr = LLDB_INVALID_ADDRESS;
 377   std::pair<PermissionsToBlockMap::iterator, PermissionsToBlockMap::iterator>
 378       range = m_memory_map.equal_range(permissions);
 379
 380   for (PermissionsToBlockMap::iterator pos = range.first; pos != range.second;
 381        ++pos) {
 382     addr = (*pos).second->ReserveBlock(byte_size);
 383     if (addr != LLDB_INVALID_ADDRESS)
 384       break;
 385   }
 386
 387   if (addr == LLDB_INVALID_ADDRESS) {
 388     AllocatedBlockSP block_sp(AllocatePage(byte_size, permissions, 16, error));
 389
 390     if (block_sp)
 391       addr = block_sp->ReserveBlock(byte_size);
 392   }
 393   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
 394   LLDB_LOGF(log,
 395             "AllocatedMemoryCache::AllocateMemory (byte_size = 0x%8.8" PRIx32
 396             ", permissions = %s) => 0x%16.16" PRIx64,
 397             (uint32_t)byte_size, GetPermissionsAsCString(permissions),
 398             (uint64_t)addr);
 399   return addr;
 400 }
 401
 402 bool AllocatedMemoryCache::DeallocateMemory(lldb::addr_t addr) {
 403   std::lock_guard<std::recursive_mutex> guard(m_mutex);
 404
 405   PermissionsToBlockMap::iterator pos, end = m_memory_map.end();
 406   bool success = false;
 407   for (pos = m_memory_map.begin(); pos != end; ++pos) {
 408     if (pos->second->Contains(addr)) {
 409       success = pos->second->FreeBlock(addr);
 410       break;
 411     }
 412   }
 413   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
 414   LLDB_LOGF(log,
 415             "AllocatedMemoryCache::DeallocateMemory (addr = 0x%16.16" PRIx64
 416             ") => %i",
 417             (uint64_t)addr, success);
 418   return success;
 419 }