Revert^4 "ART: Dual mapping of JIT code pages"
This reverts commit 1bfce389e8aba4ca7276918f2f86e5b13c5b5840.
This change adds a fix for stale data in the JIT code cache when dual
mappings of the code cache are employed. With dual mappings, newly
compiled code is written into the non-executable mapping of the code
cache. An additional data cache flush is needed to ensure the new
code is written out to the point of unification in the memory
hierarchy.
Test: manual
Bug: 66095511
Bug: 116761923
Change-Id: Ib5fa83f22ee4fee1d0f80e16b974e1677c20af9b
diff --git a/libartbase/base/mem_map.cc b/libartbase/base/mem_map.cc
index 1bf553d..92551f1 100644
--- a/libartbase/base/mem_map.cc
+++ b/libartbase/base/mem_map.cc
@@ -692,6 +692,24 @@
int tail_prot,
std::string* error_msg,
bool use_debug_name) {
+ return RemapAtEnd(new_end,
+ tail_name,
+ tail_prot,
+ MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS,
+ /* fd */ -1,
+ /* offset */ 0,
+ error_msg,
+ use_debug_name);
+}
+
+MemMap MemMap::RemapAtEnd(uint8_t* new_end,
+ const char* tail_name,
+ int tail_prot,
+ int flags,
+ int fd,
+ off_t offset,
+ std::string* error_msg,
+ bool use_debug_name) {
DCHECK_GE(new_end, Begin());
DCHECK_LE(new_end, End());
DCHECK_LE(begin_ + size_, reinterpret_cast<uint8_t*>(base_begin_) + base_size_);
@@ -715,9 +733,6 @@
DCHECK_EQ(tail_base_begin + tail_base_size, old_base_end);
DCHECK_ALIGNED(tail_base_size, kPageSize);
- unique_fd fd;
- int flags = MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS;
-
MEMORY_TOOL_MAKE_UNDEFINED(tail_base_begin, tail_base_size);
// Note: Do not explicitly unmap the tail region, mmap() with MAP_FIXED automatically
// removes old mappings for the overlapping region. This makes the operation atomic
@@ -726,13 +741,13 @@
tail_base_size,
tail_prot,
flags,
- fd.get(),
- 0));
+ fd,
+ offset));
if (actual == MAP_FAILED) {
PrintFileToLog("/proc/self/maps", LogSeverity::WARNING);
- *error_msg = StringPrintf("anonymous mmap(%p, %zd, 0x%x, 0x%x, %d, 0) failed. See process "
+ *error_msg = StringPrintf("map(%p, %zd, 0x%x, 0x%x, %d, 0) failed. See process "
"maps in the log.", tail_base_begin, tail_base_size, tail_prot, flags,
- fd.get());
+ fd);
return Invalid();
}
// Update *this.
diff --git a/libartbase/base/mem_map.h b/libartbase/base/mem_map.h
index 20eda32..309da27 100644
--- a/libartbase/base/mem_map.h
+++ b/libartbase/base/mem_map.h
@@ -261,6 +261,16 @@
std::string* error_msg,
bool use_debug_name = true);
+ // Unmap the pages of a file at end and remap them to create another memory map.
+ MemMap RemapAtEnd(uint8_t* new_end,
+ const char* tail_name,
+ int tail_prot,
+ int tail_flags,
+ int fd,
+ off_t offset,
+ std::string* error_msg,
+ bool use_debug_name = true);
+
// Take ownership of pages at the beginning of the mapping. The mapping must be an
// anonymous reservation mapping, owning entire pages. The `byte_count` must not
// exceed the size of this reservation.
diff --git a/libartbase/base/mem_map_test.cc b/libartbase/base/mem_map_test.cc
index ab3d18f..bf143d4 100644
--- a/libartbase/base/mem_map_test.cc
+++ b/libartbase/base/mem_map_test.cc
@@ -455,6 +455,53 @@
}
#endif
+TEST_F(MemMapTest, RemapFileViewAtEnd) {
+ CommonInit();
+ std::string error_msg;
+ ScratchFile scratch_file;
+
+ // Create a scratch file 3 pages large.
+ constexpr size_t kMapSize = 3 * kPageSize;
+ std::unique_ptr<uint8_t[]> data(new uint8_t[kMapSize]());
+ memset(data.get(), 1, kPageSize);
+ memset(&data[0], 0x55, kPageSize);
+ memset(&data[kPageSize], 0x5a, kPageSize);
+ memset(&data[2 * kPageSize], 0xaa, kPageSize);
+ ASSERT_TRUE(scratch_file.GetFile()->WriteFully(&data[0], kMapSize));
+
+ MemMap map = MemMap::MapFile(/*byte_count*/kMapSize,
+ PROT_READ,
+ MAP_PRIVATE,
+ scratch_file.GetFd(),
+ /*start*/0,
+ /*low_4gb*/true,
+ scratch_file.GetFilename().c_str(),
+ &error_msg);
+ ASSERT_TRUE(map.IsValid()) << error_msg;
+ ASSERT_TRUE(error_msg.empty());
+ ASSERT_EQ(map.Size(), kMapSize);
+ ASSERT_LT(reinterpret_cast<uintptr_t>(map.BaseBegin()), 1ULL << 32);
+ ASSERT_EQ(data[0], *map.Begin());
+ ASSERT_EQ(data[kPageSize], *(map.Begin() + kPageSize));
+ ASSERT_EQ(data[2 * kPageSize], *(map.Begin() + 2 * kPageSize));
+
+ for (size_t offset = 2 * kPageSize; offset > 0; offset -= kPageSize) {
+ MemMap tail = map.RemapAtEnd(map.Begin() + offset,
+ "bad_offset_map",
+ PROT_READ,
+ MAP_PRIVATE | MAP_FIXED,
+ scratch_file.GetFd(),
+ offset,
+ &error_msg);
+ ASSERT_TRUE(tail.IsValid()) << error_msg;
+ ASSERT_TRUE(error_msg.empty());
+ ASSERT_EQ(offset, map.Size());
+ ASSERT_EQ(static_cast<size_t>(kPageSize), tail.Size());
+ ASSERT_EQ(tail.Begin(), map.Begin() + map.Size());
+ ASSERT_EQ(data[offset], *tail.Begin());
+ }
+}
+
TEST_F(MemMapTest, MapAnonymousExactAddr32bitHighAddr) {
// Some MIPS32 hardware (namely the Creator Ci20 development board)
// cannot allocate in the 2GB-4GB region.