1 //===-- Memory.cpp ----------------------------------------------*- C++ -*-===//
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
MemoryCache(Process & process)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
~MemoryCache()29 MemoryCache::~MemoryCache() {}
30
Clear(bool clear_invalid_ranges)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
AddL1CacheData(lldb::addr_t addr,const void * src,size_t src_len)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
AddL1CacheData(lldb::addr_t addr,const DataBufferSP & data_buffer_sp)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
Flush(addr_t addr,size_t size)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
AddInvalidRange(lldb::addr_t base_addr,lldb::addr_t byte_size)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
RemoveInvalidRange(lldb::addr_t base_addr,lldb::addr_t byte_size)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.RemoveEntrtAtIndex(idx);
120 }
121 }
122 return false;
123 }
124
Read(addr_t addr,void * dst,size_t dst_len,Status & error)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 data_buffer_heap_up->SetByteSize(process_bytes_read);
237 m_L2_cache[curr_addr] = DataBufferSP(data_buffer_heap_up.release());
238 // We have read data and put it into the cache, continue through the
239 // loop again to get the data out of the cache...
240 }
241 }
242 }
243
244 return dst_len - bytes_left;
245 }
246
AllocatedBlock(lldb::addr_t addr,uint32_t byte_size,uint32_t permissions,uint32_t chunk_size)247 AllocatedBlock::AllocatedBlock(lldb::addr_t addr, uint32_t byte_size,
248 uint32_t permissions, uint32_t chunk_size)
249 : m_range(addr, byte_size), m_permissions(permissions),
250 m_chunk_size(chunk_size)
251 {
252 // The entire address range is free to start with.
253 m_free_blocks.Append(m_range);
254 assert(byte_size > chunk_size);
255 }
256
~AllocatedBlock()257 AllocatedBlock::~AllocatedBlock() {}
258
ReserveBlock(uint32_t size)259 lldb::addr_t AllocatedBlock::ReserveBlock(uint32_t size) {
260 // We must return something valid for zero bytes.
261 if (size == 0)
262 size = 1;
263 Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
264
265 const size_t free_count = m_free_blocks.GetSize();
266 for (size_t i=0; i<free_count; ++i)
267 {
268 auto &free_block = m_free_blocks.GetEntryRef(i);
269 const lldb::addr_t range_size = free_block.GetByteSize();
270 if (range_size >= size)
271 {
272 // We found a free block that is big enough for our data. Figure out how
273 // many chunks we will need and calculate the resulting block size we
274 // will reserve.
275 addr_t addr = free_block.GetRangeBase();
276 size_t num_chunks = CalculateChunksNeededForSize(size);
277 lldb::addr_t block_size = num_chunks * m_chunk_size;
278 lldb::addr_t bytes_left = range_size - block_size;
279 if (bytes_left == 0)
280 {
281 // The newly allocated block will take all of the bytes in this
282 // available block, so we can just add it to the allocated ranges and
283 // remove the range from the free ranges.
284 m_reserved_blocks.Insert(free_block, false);
285 m_free_blocks.RemoveEntryAtIndex(i);
286 }
287 else
288 {
289 // Make the new allocated range and add it to the allocated ranges.
290 Range<lldb::addr_t, uint32_t> reserved_block(free_block);
291 reserved_block.SetByteSize(block_size);
292 // Insert the reserved range and don't combine it with other blocks in
293 // the reserved blocks list.
294 m_reserved_blocks.Insert(reserved_block, false);
295 // Adjust the free range in place since we won't change the sorted
296 // ordering of the m_free_blocks list.
297 free_block.SetRangeBase(reserved_block.GetRangeEnd());
298 free_block.SetByteSize(bytes_left);
299 }
300 LLDB_LOGV(log, "({0}) (size = {1} ({1:x})) => {2:x}", this, size, addr);
301 return addr;
302 }
303 }
304
305 LLDB_LOGV(log, "({0}) (size = {1} ({1:x})) => {2:x}", this, size,
306 LLDB_INVALID_ADDRESS);
307 return LLDB_INVALID_ADDRESS;
308 }
309
FreeBlock(addr_t addr)310 bool AllocatedBlock::FreeBlock(addr_t addr) {
311 bool success = false;
312 auto entry_idx = m_reserved_blocks.FindEntryIndexThatContains(addr);
313 if (entry_idx != UINT32_MAX)
314 {
315 m_free_blocks.Insert(m_reserved_blocks.GetEntryRef(entry_idx), true);
316 m_reserved_blocks.RemoveEntryAtIndex(entry_idx);
317 success = true;
318 }
319 Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
320 LLDB_LOGV(log, "({0}) (addr = {1:x}) => {2}", this, addr, success);
321 return success;
322 }
323
AllocatedMemoryCache(Process & process)324 AllocatedMemoryCache::AllocatedMemoryCache(Process &process)
325 : m_process(process), m_mutex(), m_memory_map() {}
326
~AllocatedMemoryCache()327 AllocatedMemoryCache::~AllocatedMemoryCache() {}
328
Clear()329 void AllocatedMemoryCache::Clear() {
330 std::lock_guard<std::recursive_mutex> guard(m_mutex);
331 if (m_process.IsAlive()) {
332 PermissionsToBlockMap::iterator pos, end = m_memory_map.end();
333 for (pos = m_memory_map.begin(); pos != end; ++pos)
334 m_process.DoDeallocateMemory(pos->second->GetBaseAddress());
335 }
336 m_memory_map.clear();
337 }
338
339 AllocatedMemoryCache::AllocatedBlockSP
AllocatePage(uint32_t byte_size,uint32_t permissions,uint32_t chunk_size,Status & error)340 AllocatedMemoryCache::AllocatePage(uint32_t byte_size, uint32_t permissions,
341 uint32_t chunk_size, Status &error) {
342 AllocatedBlockSP block_sp;
343 const size_t page_size = 4096;
344 const size_t num_pages = (byte_size + page_size - 1) / page_size;
345 const size_t page_byte_size = num_pages * page_size;
346
347 addr_t addr = m_process.DoAllocateMemory(page_byte_size, permissions, error);
348
349 Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
350 if (log) {
351 LLDB_LOGF(log,
352 "Process::DoAllocateMemory (byte_size = 0x%8.8" PRIx32
353 ", permissions = %s) => 0x%16.16" PRIx64,
354 (uint32_t)page_byte_size, GetPermissionsAsCString(permissions),
355 (uint64_t)addr);
356 }
357
358 if (addr != LLDB_INVALID_ADDRESS) {
359 block_sp = std::make_shared<AllocatedBlock>(addr, page_byte_size,
360 permissions, chunk_size);
361 m_memory_map.insert(std::make_pair(permissions, block_sp));
362 }
363 return block_sp;
364 }
365
AllocateMemory(size_t byte_size,uint32_t permissions,Status & error)366 lldb::addr_t AllocatedMemoryCache::AllocateMemory(size_t byte_size,
367 uint32_t permissions,
368 Status &error) {
369 std::lock_guard<std::recursive_mutex> guard(m_mutex);
370
371 addr_t addr = LLDB_INVALID_ADDRESS;
372 std::pair<PermissionsToBlockMap::iterator, PermissionsToBlockMap::iterator>
373 range = m_memory_map.equal_range(permissions);
374
375 for (PermissionsToBlockMap::iterator pos = range.first; pos != range.second;
376 ++pos) {
377 addr = (*pos).second->ReserveBlock(byte_size);
378 if (addr != LLDB_INVALID_ADDRESS)
379 break;
380 }
381
382 if (addr == LLDB_INVALID_ADDRESS) {
383 AllocatedBlockSP block_sp(AllocatePage(byte_size, permissions, 16, error));
384
385 if (block_sp)
386 addr = block_sp->ReserveBlock(byte_size);
387 }
388 Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
389 LLDB_LOGF(log,
390 "AllocatedMemoryCache::AllocateMemory (byte_size = 0x%8.8" PRIx32
391 ", permissions = %s) => 0x%16.16" PRIx64,
392 (uint32_t)byte_size, GetPermissionsAsCString(permissions),
393 (uint64_t)addr);
394 return addr;
395 }
396
DeallocateMemory(lldb::addr_t addr)397 bool AllocatedMemoryCache::DeallocateMemory(lldb::addr_t addr) {
398 std::lock_guard<std::recursive_mutex> guard(m_mutex);
399
400 PermissionsToBlockMap::iterator pos, end = m_memory_map.end();
401 bool success = false;
402 for (pos = m_memory_map.begin(); pos != end; ++pos) {
403 if (pos->second->Contains(addr)) {
404 success = pos->second->FreeBlock(addr);
405 break;
406 }
407 }
408 Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
409 LLDB_LOGF(log,
410 "AllocatedMemoryCache::DeallocateMemory (addr = 0x%16.16" PRIx64
411 ") => %i",
412 (uint64_t)addr, success);
413 return success;
414 }
415