Revert "Reland "[VM runtime] Dual mapping of executable pages.""
This reverts commit 6da340bf76f104b982dc90c2f6642cceb4cdcafd.
Reason for revert: almost all benchmarks are now failing on Golem linux-x64 target. Flutter Golem build is broken
Original change's description:
> Reland "[VM runtime] Dual mapping of executable pages."
>
> This is a reland of 44186dfdcda19038616b48914d10b4b7a9ccfc2f
>
> Original change's description:
> > [VM runtime] Dual mapping of executable pages.
> >
> > Change-Id: Iaad78d324e25462ce951f4df26974a6a368c50b7
> > Reviewed-on: https://dart-review.googlesource.com/c/93377
> > Commit-Queue: Régis Crelier <regis@google.com>
> > Reviewed-by: Ryan Macnak <rmacnak@google.com>
>
> Change-Id: I7a0caa078950637d9fe831732577fd2467061099
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/95263
> Reviewed-by: Ryan Macnak <rmacnak@google.com>
TBR=rmacnak@google.com,regis@google.com
Change-Id: I3342de2584537269ffe9a53946bef27cb25a69fc
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/96161
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
diff --git a/runtime/platform/globals.h b/runtime/platform/globals.h
index ec996e9..6171827 100644
--- a/runtime/platform/globals.h
+++ b/runtime/platform/globals.h
@@ -352,14 +352,6 @@
#error Unknown architecture.
#endif
-// Determine whether dual mapping of code pages is supported.
-#if !defined(USING_SIMULATOR) && \
- (defined(HOST_OS_LINUX) || defined(HOST_OS_FUCHSIA)) && \
- !defined(HOST_OS_ANDROID) && !defined(TARGET_OS_ANDROID) && \
- !defined(TARGET_ARCH_IA32)
-#define DUAL_MAPPING_SUPPORTED 1
-#endif
-
// Disable background threads by default on armv5te. The relevant
// implementations are uniprocessors.
#if !defined(TARGET_ARCH_ARM_5TE)
diff --git a/runtime/tests/vm/vm.status b/runtime/tests/vm/vm.status
index 6554bb2..a56a92eb 100644
--- a/runtime/tests/vm/vm.status
+++ b/runtime/tests/vm/vm.status
@@ -4,7 +4,6 @@
cc/AllocGeneric_Overflow: Crash, Fail # These tests are expected to crash on all platforms.
cc/ArrayNew_Overflow_Crash: Crash, Fail # These tests are expected to crash on all platforms.
-cc/CodeExecutability: Crash, Fail # These tests are expected to crash on all platforms.
cc/CodeImmutability: Crash, Fail # These tests are expected to crash on all platforms.
cc/Dart2JSCompileAll: Fail, Crash # Issue 27369
cc/Dart2JSCompilerStats: Fail, Crash # Issue 27369
@@ -29,7 +28,6 @@
dart/appjit_cha_deopt_test: Pass, Slow # Quite slow in debug mode, uses --optimization-counter-threshold=100
[ $builder_tag == asan ]
-cc/CodeExecutability: Fail, OK # Address Sanitizer turns a crash into a failure.
cc/CodeImmutability: Fail, OK # Address Sanitizer turns a crash into a failure.
[ $builder_tag == optimization_counter_threshold ]
diff --git a/runtime/vm/code_patcher.cc b/runtime/vm/code_patcher.cc
index 7168231..4926926 100644
--- a/runtime/vm/code_patcher.cc
+++ b/runtime/vm/code_patcher.cc
@@ -12,13 +12,6 @@
DEFINE_FLAG(bool, write_protect_code, true, "Write protect jitted code");
-#if defined(DUAL_MAPPING_SUPPORTED)
-DEFINE_FLAG(bool, dual_map_code, true, "Dual map jitted code, RW and RX");
-#else
-DEFINE_FLAG(bool, dual_map_code, false, "Dual map jitted code, RW and RX");
-#endif // defined(DUAL_MAPPING_SUPPORTED)
-
-#if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_DBC)
WritableInstructionsScope::WritableInstructionsScope(uword address,
intptr_t size)
: address_(address), size_(size) {
@@ -34,7 +27,6 @@
VirtualMemory::kReadExecute);
}
}
-#endif // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_DBC)
bool MatchesPattern(uword end, const int16_t* pattern, intptr_t size) {
// When breaking within generated code in GDB, it may overwrite individual
diff --git a/runtime/vm/code_patcher.h b/runtime/vm/code_patcher.h
index 239a69d..6aa62af 100644
--- a/runtime/vm/code_patcher.h
+++ b/runtime/vm/code_patcher.h
@@ -19,12 +19,10 @@
class RawFunction;
class RawObject;
-#if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_DBC)
// Stack-allocated class to create a scope where the specified region
// [address, address + size] has write access enabled. This is used
// when patching generated code. Access is reset to read-execute in
// the destructor of this scope.
-// Dual mapping of instructions pages is not supported on these target arch.
class WritableInstructionsScope : public ValueObject {
public:
WritableInstructionsScope(uword address, intptr_t size);
@@ -34,7 +32,6 @@
const uword address_;
const intptr_t size_;
};
-#endif // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_DBC)
class CodePatcher : public AllStatic {
public:
diff --git a/runtime/vm/compiler/relocation.cc b/runtime/vm/compiler/relocation.cc
index 5d4d35f..467aa78 100644
--- a/runtime/vm/compiler/relocation.cc
+++ b/runtime/vm/compiler/relocation.cc
@@ -5,7 +5,6 @@
#include "vm/compiler/relocation.h"
#include "vm/code_patcher.h"
-#include "vm/heap/pages.h"
#include "vm/instructions.h"
#include "vm/object_store.h"
#include "vm/stub_code.h"
@@ -363,11 +362,8 @@
auto caller = Code::InstructionsOf(unresolved_call->caller);
const int32_t distance = destination_text - call_text_offset;
{
- uword addr = Instructions::PayloadStart(caller) + call_offset;
- if (FLAG_write_protect_code) {
- addr -= HeapPage::Of(caller)->AliasOffset();
- }
- PcRelativeCallPattern call(addr);
+ PcRelativeCallPattern call(Instructions::PayloadStart(caller) +
+ call_offset);
ASSERT(call.IsValid());
call.set_distance(static_cast<int32_t>(distance));
ASSERT(call.distance() == distance);
diff --git a/runtime/vm/heap/marker.cc b/runtime/vm/heap/marker.cc
index da86a36..03c9683 100644
--- a/runtime/vm/heap/marker.cc
+++ b/runtime/vm/heap/marker.cc
@@ -368,10 +368,6 @@
}
static bool TryAcquireMarkBit(RawObject* raw_obj) {
- if (FLAG_write_protect_code && raw_obj->IsInstructions()) {
- // A non-writable alias mapping may exist for instruction pages.
- raw_obj = HeapPage::ToWritable(raw_obj);
- }
if (!sync) {
raw_obj->SetMarkBitUnsynchronized();
return true;
diff --git a/runtime/vm/heap/pages.cc b/runtime/vm/heap/pages.cc
index 19d8f04..e1ac801 100644
--- a/runtime/vm/heap/pages.cc
+++ b/runtime/vm/heap/pages.cc
@@ -57,8 +57,11 @@
HeapPage* HeapPage::Allocate(intptr_t size_in_words,
PageType type,
const char* name) {
+ bool is_executable = (type == kExecutable);
+ // Create the new page executable (RWX) only if we're not in W^X mode
+ bool create_executable = !FLAG_write_protect_code && is_executable;
VirtualMemory* memory = VirtualMemory::AllocateAligned(
- size_in_words << kWordSizeLog2, kPageSize, type == kExecutable, name);
+ size_in_words << kWordSizeLog2, kPageSize, create_executable, name);
if (memory == NULL) {
return NULL;
}
@@ -211,7 +214,7 @@
VirtualMemory::Protection prot;
if (read_only) {
- if ((type_ == kExecutable) && (memory_->AliasOffset() == 0)) {
+ if (type_ == kExecutable) {
prot = VirtualMemory::kReadExecute;
} else {
prot = VirtualMemory::kReadOnly;
diff --git a/runtime/vm/heap/pages.h b/runtime/vm/heap/pages.h
index d7381d7..98d480f 100644
--- a/runtime/vm/heap/pages.h
+++ b/runtime/vm/heap/pages.h
@@ -40,8 +40,7 @@
HeapPage* next() const { return next_; }
void set_next(HeapPage* next) { next_ = next; }
- bool Contains(uword addr) const { return memory_->Contains(addr); }
- intptr_t AliasOffset() const { return memory_->AliasOffset(); }
+ bool Contains(uword addr) { return memory_->Contains(addr); }
uword object_start() const { return memory_->start() + ObjectStartOffset(); }
uword object_end() const { return object_end_; }
@@ -71,8 +70,7 @@
}
// Warning: This does not work for objects on image pages because image pages
- // are not aligned. However, it works for objects on large pages, because
- // only one object is allocated per large page.
+ // are not aligned.
static HeapPage* Of(RawObject* obj) {
ASSERT(obj->IsHeapObject());
ASSERT(obj->IsOldObject());
@@ -80,45 +78,10 @@
kPageMask);
}
- // Warning: This does not work for addresses on image pages or on large pages.
- static HeapPage* Of(uword addr) {
+ static HeapPage* Of(uintptr_t addr) {
return reinterpret_cast<HeapPage*>(addr & kPageMask);
}
- // Warning: This does not work for objects on image pages.
- static RawObject* ToExecutable(RawObject* obj) {
- HeapPage* page = Of(obj);
- VirtualMemory* memory = page->memory_;
- const intptr_t alias_offset = memory->AliasOffset();
- if (alias_offset == 0) {
- return obj; // Not aliased.
- }
- uword addr = RawObject::ToAddr(obj);
- if (memory->Contains(addr)) {
- return RawObject::FromAddr(addr + alias_offset);
- }
- // obj is executable.
- ASSERT(memory->ContainsAlias(addr));
- return obj;
- }
-
- // Warning: This does not work for objects on image pages.
- static RawObject* ToWritable(RawObject* obj) {
- HeapPage* page = Of(obj);
- VirtualMemory* memory = page->memory_;
- const intptr_t alias_offset = memory->AliasOffset();
- if (alias_offset == 0) {
- return obj; // Not aliased.
- }
- uword addr = RawObject::ToAddr(obj);
- if (memory->ContainsAlias(addr)) {
- return RawObject::FromAddr(addr - alias_offset);
- }
- // obj is writable.
- ASSERT(memory->Contains(addr));
- return obj;
- }
-
// 1 card = 128 slots.
static const intptr_t kSlotsPerCardLog2 = 7;
static const intptr_t kBytesPerCardLog2 = kWordSizeLog2 + kSlotsPerCardLog2;
diff --git a/runtime/vm/heap/verifier.cc b/runtime/vm/heap/verifier.cc
index 237777e..8ea2fdb 100644
--- a/runtime/vm/heap/verifier.cc
+++ b/runtime/vm/heap/verifier.cc
@@ -49,10 +49,6 @@
RawObject* raw_obj = *current;
if (raw_obj->IsHeapObject()) {
if (!allocated_set_->Contains(raw_obj)) {
- if (raw_obj->IsInstructions() &&
- allocated_set_->Contains(HeapPage::ToWritable(raw_obj))) {
- continue;
- }
uword raw_addr = RawObject::ToAddr(raw_obj);
FATAL1("Invalid object pointer encountered %#" Px "\n", raw_addr);
}
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 7014578..864555d 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -2015,12 +2015,7 @@
bool Object::IsReadOnly() const {
if (FLAG_verify_handles && raw()->IsReadOnly()) {
Heap* vm_isolate_heap = Dart::vm_isolate()->heap();
- uword addr = RawObject::ToAddr(raw());
- if (!vm_isolate_heap->Contains(addr)) {
- ASSERT(FLAG_write_protect_code);
- addr = RawObject::ToAddr(HeapPage::ToWritable(raw()));
- ASSERT(vm_isolate_heap->Contains(addr));
- }
+ ASSERT(vm_isolate_heap->Contains(RawObject::ToAddr(raw())));
}
return raw()->IsReadOnly();
}
@@ -2077,12 +2072,8 @@
Isolate* isolate = Isolate::Current();
Heap* isolate_heap = isolate->heap();
Heap* vm_isolate_heap = Dart::vm_isolate()->heap();
- uword addr = RawObject::ToAddr(raw_);
- if (!isolate_heap->Contains(addr) && !vm_isolate_heap->Contains(addr)) {
- ASSERT(FLAG_write_protect_code);
- addr = RawObject::ToAddr(HeapPage::ToWritable(raw_));
- ASSERT(isolate_heap->Contains(addr) || vm_isolate_heap->Contains(addr));
- }
+ ASSERT(isolate_heap->Contains(RawObject::ToAddr(raw_)) ||
+ vm_isolate_heap->Contains(RawObject::ToAddr(raw_)));
}
}
#endif
@@ -14571,24 +14562,6 @@
object->raw());
}
- // Write protect instructions and, if supported by OS, use dual mapping
- // for execution.
- if (FLAG_write_protect_code) {
- uword address = RawObject::ToAddr(instrs.raw());
- // Check if a dual mapping exists.
- instrs = Instructions::RawCast(HeapPage::ToExecutable(instrs.raw()));
- uword exec_address = RawObject::ToAddr(instrs.raw());
- if (exec_address != address) {
- VirtualMemory::Protect(reinterpret_cast<void*>(address),
- instrs.raw()->HeapSize(),
- VirtualMemory::kReadOnly);
- address = exec_address;
- }
- VirtualMemory::Protect(reinterpret_cast<void*>(address),
- instrs.raw()->HeapSize(),
- VirtualMemory::kReadExecute);
- }
-
// Hook up Code and Instructions objects.
code.SetActiveInstructions(instrs);
code.set_instructions(instrs);
@@ -14599,6 +14572,13 @@
code.set_object_pool(object_pool->raw());
}
+ if (FLAG_write_protect_code) {
+ uword address = RawObject::ToAddr(instrs.raw());
+ VirtualMemory::Protect(reinterpret_cast<void*>(address),
+ instrs.raw()->HeapSize(),
+ VirtualMemory::kReadExecute);
+ }
+
#if defined(DART_PRECOMPILER)
if (stats != nullptr) {
stats->Finalize();
diff --git a/runtime/vm/object.h b/runtime/vm/object.h
index 05ba3eb..e19f357 100644
--- a/runtime/vm/object.h
+++ b/runtime/vm/object.h
@@ -4651,7 +4651,6 @@
class Code : public Object {
public:
- // When dual mapping, this returns the executable view.
RawInstructions* active_instructions() const {
#if defined(DART_PRECOMPILED_RUNTIME)
UNREACHABLE();
@@ -4661,7 +4660,6 @@
#endif
}
- // When dual mapping, these return the executable view.
RawInstructions* instructions() const { return raw_ptr()->instructions_; }
static RawInstructions* InstructionsOf(const RawCode* code) {
return code->ptr()->instructions_;
@@ -5142,7 +5140,6 @@
FINAL_HEAP_OBJECT_IMPLEMENTATION(Code, Object);
friend class Class;
- friend class CodeTestHelper;
friend class SnapshotWriter;
friend class StubCode; // for set_object_pool
friend class Precompiler; // for set_object_pool
@@ -9143,12 +9140,8 @@
Isolate* isolate = Isolate::Current();
Heap* isolate_heap = isolate->heap();
Heap* vm_isolate_heap = Dart::vm_isolate()->heap();
- uword addr = RawObject::ToAddr(raw_);
- if (!isolate_heap->Contains(addr) && !vm_isolate_heap->Contains(addr)) {
- ASSERT(FLAG_write_protect_code);
- addr = RawObject::ToAddr(HeapPage::ToWritable(raw_));
- ASSERT(isolate_heap->Contains(addr) || vm_isolate_heap->Contains(addr));
- }
+ ASSERT(isolate_heap->Contains(RawObject::ToAddr(raw_)) ||
+ vm_isolate_heap->Contains(RawObject::ToAddr(raw_)));
}
#endif
}
diff --git a/runtime/vm/object_graph.cc b/runtime/vm/object_graph.cc
index 3e52f53..5a5e740 100644
--- a/runtime/vm/object_graph.cc
+++ b/runtime/vm/object_graph.cc
@@ -44,12 +44,7 @@
if (!include_vm_objects_ && !IsUserClass((*current)->GetClassId())) {
continue;
}
- if (FLAG_write_protect_code && (*current)->IsInstructions()) {
- // A non-writable alias mapping may exist for instruction pages.
- HeapPage::ToWritable(*current)->SetGraphMarked();
- } else {
- (*current)->SetGraphMarked();
- }
+ (*current)->SetGraphMarked();
Node node;
node.ptr = current;
node.obj = *current;
diff --git a/runtime/vm/object_test.cc b/runtime/vm/object_test.cc
index 4664ee7..c0d9526 100644
--- a/runtime/vm/object_test.cc
+++ b/runtime/vm/object_test.cc
@@ -23,7 +23,6 @@
namespace dart {
-DECLARE_FLAG(bool, dual_map_code);
DECLARE_FLAG(bool, write_protect_code);
static RawClass* CreateDummyClass(const String& class_name,
@@ -2508,56 +2507,8 @@
if (!FLAG_write_protect_code) {
// Since this test is expected to crash, crash if write protection of code
// is switched off.
- FATAL("Test requires --write-protect-code; skip by forcing expected crash");
- }
- MallocHooks::set_stack_trace_collection_enabled(
- stack_trace_collection_enabled);
-}
-
-class CodeTestHelper {
- public:
- static void SetInstructions(const Code& code,
- const Instructions& instructions) {
- code.SetActiveInstructions(instructions);
- code.set_instructions(instructions);
- }
-};
-
-// Test for executability of generated instructions. The test crashes with a
-// segmentation fault when executing the writeable view.
-ISOLATE_UNIT_TEST_CASE(CodeExecutability) {
- bool stack_trace_collection_enabled =
- MallocHooks::stack_trace_collection_enabled();
- MallocHooks::set_stack_trace_collection_enabled(false);
- extern void GenerateIncrement(Assembler * assembler);
- ObjectPoolBuilder object_pool_builder;
- Assembler _assembler_(&object_pool_builder);
- GenerateIncrement(&_assembler_);
- const Function& function = Function::Handle(CreateFunction("Test_Code"));
- Code& code = Code::Handle(Code::FinalizeCodeAndNotify(
- function, nullptr, &_assembler_, Code::PoolAttachment::kAttachPool));
- function.AttachCode(code);
- Instructions& instructions = Instructions::Handle(code.instructions());
- uword payload_start = instructions.PayloadStart();
- EXPECT_EQ(instructions.raw(), Instructions::FromPayloadStart(payload_start));
- // Execute the executable view of the instructions (default).
- Object& result =
- Object::Handle(DartEntry::InvokeFunction(function, Array::empty_array()));
- EXPECT_EQ(1, Smi::Cast(result).Value());
- // Switch to the writeable but non-executable view of the instructions.
- instructions ^= HeapPage::ToWritable(instructions.raw());
- payload_start = instructions.PayloadStart();
- EXPECT_EQ(instructions.raw(), Instructions::FromPayloadStart(payload_start));
- // Hook up Code and Instructions objects.
- CodeTestHelper::SetInstructions(code, instructions);
- function.AttachCode(code);
- // Try executing the generated code, expected to crash.
- result = DartEntry::InvokeFunction(function, Array::empty_array());
- EXPECT_EQ(1, Smi::Cast(result).Value());
- if (!FLAG_dual_map_code) {
- // Since this test is expected to crash, crash if dual mapping of code
- // is switched off.
- FATAL("Test requires --dual-map-code; skip by forcing expected crash");
+ // TODO(regis, fschneider): Should this be FATAL() instead?
+ OS::DebugBreak();
}
MallocHooks::set_stack_trace_collection_enabled(
stack_trace_collection_enabled);
diff --git a/runtime/vm/os_linux.cc b/runtime/vm/os_linux.cc
index 20db94d..1079bdb 100644
--- a/runtime/vm/os_linux.cc
+++ b/runtime/vm/os_linux.cc
@@ -558,7 +558,9 @@
}
}
-// TODO(regis): Function called only from the simulator.
+// TODO(regis, iposva): When this function is no longer called from the
+// CodeImmutability test in object_test.cc, it will be called only from the
+// simulator, which means that only the Intel implementation is needed.
void OS::DebugBreak() {
__builtin_trap();
}
diff --git a/runtime/vm/virtual_memory.cc b/runtime/vm/virtual_memory.cc
index 48ba867..6d73ba0 100644
--- a/runtime/vm/virtual_memory.cc
+++ b/runtime/vm/virtual_memory.cc
@@ -17,18 +17,12 @@
void VirtualMemory::Truncate(intptr_t new_size) {
ASSERT(Utils::IsAligned(new_size, PageSize()));
ASSERT(new_size <= size());
- if (reserved_.size() ==
- region_.size()) { // Don't create holes in reservation.
+ if (reserved_.size() == region_.size()) { // Don't create holes in reservation.
FreeSubSegment(reinterpret_cast<void*>(start() + new_size),
size() - new_size);
reserved_.set_size(new_size);
- if (AliasOffset() != 0) {
- FreeSubSegment(reinterpret_cast<void*>(alias_.start() + new_size),
- alias_.size() - new_size);
- }
}
region_.Subregion(region_, 0, new_size);
- alias_.Subregion(alias_, 0, new_size);
}
VirtualMemory* VirtualMemory::ForImagePage(void* pointer, uword size) {
@@ -37,7 +31,7 @@
MemoryRegion region(pointer, size);
MemoryRegion reserved(0, 0); // NULL reservation indicates VM should not
// attempt to free this memory.
- VirtualMemory* memory = new VirtualMemory(region, region, reserved);
+ VirtualMemory* memory = new VirtualMemory(region, reserved);
ASSERT(!memory->vm_owns_region());
return memory;
}
diff --git a/runtime/vm/virtual_memory.h b/runtime/vm/virtual_memory.h
index 496e63c..6d74541 100644
--- a/runtime/vm/virtual_memory.h
+++ b/runtime/vm/virtual_memory.h
@@ -28,14 +28,10 @@
uword end() const { return region_.end(); }
void* address() const { return region_.pointer(); }
intptr_t size() const { return region_.size(); }
- intptr_t AliasOffset() const { return alias_.start() - region_.start(); }
static void Init();
bool Contains(uword addr) const { return region_.Contains(addr); }
- bool ContainsAlias(uword addr) const {
- return (AliasOffset() != 0) && alias_.Contains(addr);
- }
// Changes the protection of the virtual memory area.
static void Protect(void* address, intptr_t size, Protection mode);
@@ -76,22 +72,14 @@
// can give back the virtual memory to the system. Returns true on success.
static void FreeSubSegment(void* address, intptr_t size);
- // These constructors are only used internally when reserving new virtual
- // spaces. They do not reserve any virtual address space on their own.
+ // This constructor is only used internally when reserving new virtual spaces.
+ // It does not reserve any virtual address space on its own.
VirtualMemory(const MemoryRegion& region,
- const MemoryRegion& alias,
const MemoryRegion& reserved)
- : region_(region), alias_(alias), reserved_(reserved) {}
-
- VirtualMemory(const MemoryRegion& region, const MemoryRegion& reserved)
- : region_(region), alias_(region), reserved_(reserved) {}
+ : region_(region), reserved_(reserved) {}
MemoryRegion region_;
- // Optional secondary mapping of region_ to a virtual space with different
- // protection, e.g. allowing code execution.
- MemoryRegion alias_;
-
// The underlying reservation not yet given back to the OS.
// Its address might disagree with region_ due to aligned allocations.
// Its size might disagree with region_ due to Truncate.
@@ -99,10 +87,6 @@
static uword page_size_;
-#if defined(HOST_OS_FUCHSIA)
- static uword base_; // Cached base of root vmar.
-#endif
-
DISALLOW_IMPLICIT_CONSTRUCTORS(VirtualMemory);
};
diff --git a/runtime/vm/virtual_memory_fuchsia.cc b/runtime/vm/virtual_memory_fuchsia.cc
index b627ddf..63c47ae 100644
--- a/runtime/vm/virtual_memory_fuchsia.cc
+++ b/runtime/vm/virtual_memory_fuchsia.cc
@@ -35,29 +35,15 @@
namespace dart {
-DECLARE_FLAG(bool, dual_map_code);
DECLARE_FLAG(bool, write_protect_code);
uword VirtualMemory::page_size_ = 0;
-uword VirtualMemory::base_ = 0;
void VirtualMemory::Init() {
page_size_ = getpagesize();
-
- // Cache the base of zx_vmar_root_self() which is used to align mappings.
- zx_info_vmar_t buf[1];
- size_t actual;
- size_t avail;
- zx_status_t status =
- zx_object_get_info(zx_vmar_root_self(), ZX_INFO_VMAR, buf,
- sizeof(zx_info_vmar_t), &actual, &avail);
- if (status != ZX_OK) {
- FATAL1("zx_object_get_info failed: %s\n", zx_status_get_string(status));
- }
- base_ = buf[0].base;
}
-static void Unmap(zx_handle_t vmar, uword start, uword end) {
+static void unmap(zx_handle_t vmar, uword start, uword end) {
ASSERT(start <= end);
const uword size = end - start;
if (size == 0) {
@@ -70,61 +56,28 @@
}
}
-static void* MapAligned(zx_handle_t vmar,
- zx_handle_t vmo,
- zx_vm_option_t options,
- uword size,
- uword alignment,
- uword vmar_base,
- uword padded_size) {
- uword base;
- zx_status_t status =
- zx_vmar_map(vmar, options, 0, vmo, 0u, padded_size, &base);
- LOG_INFO("zx_vmar_map(%u, 0x%lx, 0x%lx)\n", options, base, padded_size);
-
- if (status != ZX_OK) {
- LOG_ERR("zx_vmar_map(%u, 0x%lx, 0x%lx) failed: %s\n", options, base,
- padded_size, zx_status_get_string(status));
- return NULL;
- }
- const uword aligned_base = Utils::RoundUp(base, alignment);
- const zx_vm_option_t overwrite_options = options | ZX_VM_SPECIFIC_OVERWRITE;
- status = zx_vmar_map(vmar, overwrite_options, aligned_base - vmar_base, vmo,
- 0u, size, &base);
- LOG_INFO("zx_vmar_map(%u, 0x%lx, 0x%lx)\n", overwrite_options,
- aligned_base - vmar_base, size);
-
- if (status != ZX_OK) {
- LOG_ERR("zx_vmar_map(%u, 0x%lx, 0x%lx) failed: %s\n", overwrite_options,
- aligned_base - vmar_base, size, zx_status_get_string(status));
- return NULL;
- }
- ASSERT(base == aligned_base);
- return reinterpret_cast<void*>(base);
-}
-
VirtualMemory* VirtualMemory::AllocateAligned(intptr_t size,
intptr_t alignment,
bool is_executable,
const char* name) {
- // When FLAG_write_protect_code is active, code memory (indicated by
- // is_executable = true) is allocated as non-executable and later
- // changed to executable via VirtualMemory::Protect, which requires
- // ZX_RIGHT_EXECUTE on the underlying VMO.
- // In addition, dual mapping of the same underlying code memory is provided.
- const bool dual_mapping =
- is_executable && FLAG_write_protect_code && FLAG_dual_map_code;
+ // When FLAG_write_protect_code is active, the VM allocates code
+ // memory with !is_executable, and later changes to executable via
+ // VirtualMemory::Protect, which requires ZX_RIGHT_EXECUTE on the
+ // underlying VMO. Conservatively assume all memory needs to be
+ // executable in this mode.
+ // TODO(mdempsky): Make into parameter.
+ const bool can_prot_exec = FLAG_write_protect_code;
ASSERT(Utils::IsAligned(size, page_size_));
ASSERT(Utils::IsPowerOfTwo(alignment));
ASSERT(Utils::IsAligned(alignment, page_size_));
- const intptr_t padded_size = size + alignment - page_size_;
+ const intptr_t allocated_size = size + alignment - page_size_;
zx_handle_t vmar = zx_vmar_root_self();
zx_handle_t vmo = ZX_HANDLE_INVALID;
- zx_status_t status = zx_vmo_create(size, 0u, &vmo);
+ zx_status_t status = zx_vmo_create(allocated_size, 0u, &vmo);
if (status != ZX_OK) {
- LOG_ERR("zx_vmo_create(0x%lx) failed: %s\n", size,
+ LOG_ERR("zx_vmo_create(%ld) failed: %s\n", size,
zx_status_get_string(status));
return NULL;
}
@@ -133,9 +86,9 @@
zx_object_set_property(vmo, ZX_PROP_NAME, name, strlen(name));
}
- if (is_executable) {
+ if (is_executable || can_prot_exec) {
// Add ZX_RIGHT_EXECUTE permission to VMO, so it can be mapped
- // into memory as executable (now or later).
+ // into memory as executable.
status = zx_vmo_replace_as_executable(vmo, ZX_HANDLE_INVALID, &vmo);
if (status != ZX_OK) {
LOG_ERR("zx_vmo_replace_as_executable() failed: %s\n",
@@ -144,59 +97,39 @@
}
}
- const zx_vm_option_t region_options =
- ZX_VM_PERM_READ | ZX_VM_PERM_WRITE |
- ((is_executable && !FLAG_write_protect_code) ? ZX_VM_PERM_EXECUTE : 0);
- void* region_ptr = MapAligned(vmar, vmo, region_options, size, alignment,
- base_, padded_size);
- if (region_ptr == NULL) {
+ const zx_vm_option_t options = ZX_VM_PERM_READ | ZX_VM_PERM_WRITE |
+ (is_executable ? ZX_VM_PERM_EXECUTE : 0);
+ uword base;
+ status = zx_vmar_map(vmar, options, 0u, vmo, 0u, allocated_size, &base);
+ zx_handle_close(vmo);
+ if (status != ZX_OK) {
+ LOG_ERR("zx_vmar_map(%u, %ld) failed: %s\n", flags, size,
+ zx_status_get_string(status));
return NULL;
}
- MemoryRegion region(region_ptr, size);
- VirtualMemory* result;
+ const uword aligned_base = Utils::RoundUp(base, alignment);
- if (dual_mapping) {
- // ZX_VM_PERM_EXECUTE is added later via VirtualMemory::Protect.
- const zx_vm_option_t alias_options = ZX_VM_PERM_READ;
- void* alias_ptr = MapAligned(vmar, vmo, alias_options, size, alignment,
- base_, padded_size);
- if (alias_ptr == NULL) {
- const uword region_base = reinterpret_cast<uword>(region_ptr);
- Unmap(vmar, region_base, region_base + size);
- return NULL;
- }
- ASSERT(region_ptr != alias_ptr);
- MemoryRegion alias(alias_ptr, size);
- result = new VirtualMemory(region, alias, region);
- } else {
- result = new VirtualMemory(region, region, region);
- }
- zx_handle_close(vmo);
- return result;
+ unmap(vmar, base, aligned_base);
+ unmap(vmar, aligned_base + size, base + allocated_size);
+
+ MemoryRegion region(reinterpret_cast<void*>(aligned_base), size);
+ return new VirtualMemory(region, region);
}
VirtualMemory::~VirtualMemory() {
// Reserved region may be empty due to VirtualMemory::Truncate.
if (vm_owns_region() && reserved_.size() != 0) {
- Unmap(zx_vmar_root_self(), reserved_.start(), reserved_.end());
- LOG_INFO("zx_vmar_unmap(0x%lx, 0x%lx) success\n", reserved_.start(),
+ unmap(zx_vmar_root_self(), reserved_.start(), reserved_.end());
+ LOG_INFO("zx_vmar_unmap(%lx, %lx) success\n", reserved_.start(),
reserved_.size());
-
- const intptr_t alias_offset = AliasOffset();
- if (alias_offset != 0) {
- Unmap(zx_vmar_root_self(), reserved_.start() + alias_offset,
- reserved_.end() + alias_offset);
- LOG_INFO("zx_vmar_unmap(0x%lx, 0x%lx) success\n",
- reserved_.start() + alias_offset, reserved_.size());
- }
}
}
void VirtualMemory::FreeSubSegment(void* address, intptr_t size) {
const uword start = reinterpret_cast<uword>(address);
- Unmap(zx_vmar_root_self(), start, start + size);
- LOG_INFO("zx_vmar_unmap(0x%p, 0x%lx) success\n", address, size);
+ unmap(zx_vmar_root_self(), start, start + size);
+ LOG_INFO("zx_vmar_unmap(%p, %lx) success\n", address, size);
}
void VirtualMemory::Protect(void* address, intptr_t size, Protection mode) {
@@ -228,12 +161,12 @@
}
zx_status_t status = zx_vmar_protect(zx_vmar_root_self(), prot, page_address,
end_address - page_address);
- LOG_INFO("zx_vmar_protect(%u, 0x%lx, 0x%lx)\n", prot, page_address,
- end_address - page_address);
if (status != ZX_OK) {
- FATAL3("zx_vmar_protect(0x%lx, 0x%lx) failed: %s\n", page_address,
+ FATAL3("zx_vmar_protect(%lx, %lx) failed: %s\n", page_address,
end_address - page_address, zx_status_get_string(status));
}
+ LOG_INFO("zx_vmar_protect(%lx, %lx, %x) success\n", page_address,
+ end_address - page_address, prot);
}
} // namespace dart
diff --git a/runtime/vm/virtual_memory_posix.cc b/runtime/vm/virtual_memory_posix.cc
index 8767250..31c7f15 100644
--- a/runtime/vm/virtual_memory_posix.cc
+++ b/runtime/vm/virtual_memory_posix.cc
@@ -9,7 +9,6 @@
#include <errno.h>
#include <sys/mman.h>
-#include <sys/syscall.h>
#include <unistd.h>
#include "platform/assert.h"
@@ -17,13 +16,6 @@
#include "vm/isolate.h"
-// #define VIRTUAL_MEMORY_LOGGING 1
-#if defined(VIRTUAL_MEMORY_LOGGING)
-#define LOG_INFO(msg, ...) OS::PrintErr(msg, ##__VA_ARGS__)
-#else
-#define LOG_INFO(msg, ...)
-#endif // defined(VIRTUAL_MEMORY_LOGGING)
-
namespace dart {
// standard MAP_FAILED causes "error: use of old-style cast" as it
@@ -31,9 +23,6 @@
#undef MAP_FAILED
#define MAP_FAILED reinterpret_cast<void*>(-1)
-DECLARE_FLAG(bool, dual_map_code);
-DECLARE_FLAG(bool, write_protect_code);
-
uword VirtualMemory::page_size_ = 0;
void VirtualMemory::Init() {
@@ -56,97 +45,17 @@
}
}
-#if defined(DUAL_MAPPING_SUPPORTED)
-// Wrapper to call memfd_create syscall.
-static inline int memfd_create(const char* name, unsigned int flags) {
- return syscall(__NR_memfd_create, name, flags);
-}
-
-static void* MapAligned(int fd,
- int prot,
- intptr_t size,
- intptr_t alignment,
- intptr_t allocated_size) {
- void* address =
- mmap(NULL, allocated_size, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
- LOG_INFO("mmap(NULL, 0x%" Px ", PROT_NONE, ...): %p\n", allocated_size,
- address);
- if (address == MAP_FAILED) {
- return NULL;
- }
-
- const uword base = reinterpret_cast<uword>(address);
- const uword aligned_base = Utils::RoundUp(base, alignment);
-
- // Guarantee the alignment by mapping at a fixed address inside the above
- // mapping. Overlapping region will be automatically discarded in the above
- // mapping. Manually discard non-overlapping regions.
- address = mmap(reinterpret_cast<void*>(aligned_base), size, prot,
- MAP_SHARED | MAP_FIXED, fd, 0);
- LOG_INFO("mmap(0x%" Px ", 0x%" Px ", %u, ...): %p\n", aligned_base, size,
- prot, address);
- if (address == MAP_FAILED) {
- unmap(base, base + allocated_size);
- return NULL;
- }
- ASSERT(address == reinterpret_cast<void*>(aligned_base));
- unmap(base, aligned_base);
- unmap(aligned_base + size, base + allocated_size);
- return address;
-}
-#endif // defined(DUAL_MAPPING_SUPPORTED)
-
VirtualMemory* VirtualMemory::AllocateAligned(intptr_t size,
intptr_t alignment,
bool is_executable,
const char* name) {
- // When FLAG_write_protect_code is active, code memory (indicated by
- // is_executable = true) is allocated as non-executable and later
- // changed to executable via VirtualMemory::Protect.
ASSERT(Utils::IsAligned(size, page_size_));
ASSERT(Utils::IsPowerOfTwo(alignment));
ASSERT(Utils::IsAligned(alignment, page_size_));
const intptr_t allocated_size = size + alignment - page_size_;
-#if defined(DUAL_MAPPING_SUPPORTED)
- int fd = -1;
- const bool dual_mapping =
- is_executable && FLAG_write_protect_code && FLAG_dual_map_code;
- if (dual_mapping) {
- fd = memfd_create("/dual_mapping", 0);
- if ((fd == -1) || (ftruncate(fd, size) == -1)) {
- close(fd);
- return NULL;
- }
- const int region_prot = PROT_READ | PROT_WRITE;
- void* region_ptr =
- MapAligned(fd, region_prot, size, alignment, allocated_size);
- if (region_ptr == NULL) {
- close(fd);
- return NULL;
- }
- MemoryRegion region(region_ptr, size);
- // PROT_EXEC is added later via VirtualMemory::Protect.
- const int alias_prot = PROT_READ;
- void* alias_ptr =
- MapAligned(fd, alias_prot, size, alignment, allocated_size);
- close(fd);
- if (alias_ptr == NULL) {
- const uword region_base = reinterpret_cast<uword>(region_ptr);
- unmap(region_base, region_base + size);
- return NULL;
- }
- ASSERT(region_ptr != alias_ptr);
- MemoryRegion alias(alias_ptr, size);
- return new VirtualMemory(region, alias, region);
- }
-#endif // defined(DUAL_MAPPING_SUPPORTED)
- const int prot =
- PROT_READ | PROT_WRITE |
- ((is_executable && !FLAG_write_protect_code) ? PROT_EXEC : 0);
+ const int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
void* address =
- mmap(NULL, allocated_size, prot, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
- LOG_INFO("mmap(NULL, 0x%" Px ", %u, ...): %p\n", allocated_size, prot,
- address);
+ mmap(NULL, allocated_size, prot, MAP_PRIVATE | MAP_ANON, -1, 0);
if (address == MAP_FAILED) {
return NULL;
}
@@ -164,10 +73,6 @@
VirtualMemory::~VirtualMemory() {
if (vm_owns_region()) {
unmap(reserved_.start(), reserved_.end());
- const intptr_t alias_offset = AliasOffset();
- if (alias_offset != 0) {
- unmap(reserved_.start() + alias_offset, reserved_.end() + alias_offset);
- }
}
}
@@ -209,15 +114,11 @@
int error = errno;
const int kBufferSize = 1024;
char error_buf[kBufferSize];
- LOG_INFO("mprotect(0x%" Px ", 0x%" Px ", %u) failed\n", page_address,
- end_address - page_address, prot);
FATAL2("mprotect error: %d (%s)", error,
Utils::StrError(error, error_buf, kBufferSize));
}
- LOG_INFO("mprotect(0x%" Px ", 0x%" Px ", %u) ok\n", page_address,
- end_address - page_address, prot);
}
} // namespace dart
-#endif // defined(HOST_OS_ANDROID ... HOST_OS_LINUX ... HOST_OS_MACOS)
+#endif // defined(HOST_OS_ANDROID) || defined(HOST_OS_LINUX) || defined(HOST_OS_MACOS)
diff --git a/runtime/vm/virtual_memory_win.cc b/runtime/vm/virtual_memory_win.cc
index 3ec743f0..9c917b3 100644
--- a/runtime/vm/virtual_memory_win.cc
+++ b/runtime/vm/virtual_memory_win.cc
@@ -14,8 +14,6 @@
namespace dart {
-DECLARE_FLAG(bool, write_protect_code);
-
uword VirtualMemory::page_size_ = 0;
void VirtualMemory::Init() {
@@ -28,16 +26,11 @@
intptr_t alignment,
bool is_executable,
const char* name) {
- // When FLAG_write_protect_code is active, code memory (indicated by
- // is_executable = true) is allocated as non-executable and later
- // changed to executable via VirtualMemory::Protect.
ASSERT(Utils::IsAligned(size, page_size_));
ASSERT(Utils::IsPowerOfTwo(alignment));
ASSERT(Utils::IsAligned(alignment, page_size_));
intptr_t reserved_size = size + alignment - page_size_;
- int prot = (is_executable && !FLAG_write_protect_code)
- ? PAGE_EXECUTE_READWRITE
- : PAGE_READWRITE;
+ int prot = is_executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
void* address = VirtualAlloc(NULL, reserved_size, MEM_RESERVE, prot);
if (address == NULL) {
return NULL;
