// Copyright 2016 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef V8_TRAP_HANDLER_TRAP_HANDLER_H_ #define V8_TRAP_HANDLER_TRAP_HANDLER_H_ #include <stdint.h> #include <stdlib.h> #include <atomic> #include "include/v8config.h" #include "src/base/immediate-crash.h" namespace v8 { namespace internal { namespace trap_handler { // X64 on Linux, Windows, MacOS, FreeBSD. #if V8_HOST_ARCH_X64 && V8_TARGET_ARCH_X64 && \ ((V8_OS_LINUX && !V8_OS_ANDROID) || V8_OS_WIN || V8_OS_DARWIN || \ V8_OS_FREEBSD) #define V8_TRAP_HANDLER_SUPPORTED … // Arm64 (non-simulator) on Mac and Linux. #elif V8_TARGET_ARCH_ARM64 && V8_HOST_ARCH_ARM64 && \ (V8_OS_DARWIN || (V8_OS_LINUX && !V8_OS_ANDROID)) #define V8_TRAP_HANDLER_SUPPORTED … // Arm64 simulator on x64 on Linux, Mac, or Windows. // // The simulator case uses some inline assembly code, which cannot be // compiled with MSVC, so don't enable the trap handler in that case. // (MSVC #defines _MSC_VER, but so does Clang when targeting Windows, hence // the check for __clang__.) #elif V8_TARGET_ARCH_ARM64 && V8_HOST_ARCH_X64 && \ (V8_OS_LINUX || V8_OS_DARWIN || V8_OS_WIN) && \ (!defined(_MSC_VER) || defined(__clang__)) #define V8_TRAP_HANDLER_VIA_SIMULATOR #define V8_TRAP_HANDLER_SUPPORTED … // Loong64 (non-simulator) on Linux. #elif V8_TARGET_ARCH_LOONG64 && V8_HOST_ARCH_LOONG64 && V8_OS_LINUX #define V8_TRAP_HANDLER_SUPPORTED … // Loong64 simulator on x64 on Linux #elif V8_TARGET_ARCH_LOONG64 && V8_HOST_ARCH_X64 && V8_OS_LINUX #define V8_TRAP_HANDLER_VIA_SIMULATOR #define V8_TRAP_HANDLER_SUPPORTED … // RISCV64 (non-simulator) on Linux. #elif V8_TARGET_ARCH_RISCV64 && V8_HOST_ARCH_RISCV64 && V8_OS_LINUX && \ !V8_OS_ANDROID #define V8_TRAP_HANDLER_SUPPORTED … // RISCV64 simulator on x64 on Linux #elif V8_TARGET_ARCH_RISCV64 && V8_HOST_ARCH_X64 && V8_OS_LINUX #define V8_TRAP_HANDLER_VIA_SIMULATOR #define V8_TRAP_HANDLER_SUPPORTED … // Everything else is unsupported. #else #define V8_TRAP_HANDLER_SUPPORTED … #endif #if V8_OS_ANDROID && V8_TRAP_HANDLER_SUPPORTED // It would require some careful security review before the trap handler // can be enabled on Android. Android may do unexpected things with signal // handling and crash reporting that could open up security holes in V8's // trap handling. #error "The V8 trap handler should not be enabled on Android" #endif // Setup for shared library export. #if defined(BUILDING_V8_SHARED_PRIVATE) && defined(V8_OS_WIN) #define TH_EXPORT_PRIVATE … #elif defined(BUILDING_V8_SHARED_PRIVATE) #define TH_EXPORT_PRIVATE … #elif defined(USING_V8_SHARED_PRIVATE) && defined(V8_OS_WIN) #define TH_EXPORT_PRIVATE … #else #define TH_EXPORT_PRIVATE #endif #define TH_CHECK(condition) … #ifdef DEBUG #define TH_DCHECK(condition) … #else #define TH_DCHECK … #endif #if defined(__has_feature) #if __has_feature(address_sanitizer) #define TH_DISABLE_ASAN … #else #define TH_DISABLE_ASAN #endif #else #define TH_DISABLE_ASAN #endif struct ProtectedInstructionData { … }; const int kInvalidIndex = …; /// Adds the handler data to the place where the trap handler will find it. /// /// This returns a number that can be used to identify the handler data to /// ReleaseHandlerData, or -1 on failure. int TH_EXPORT_PRIVATE RegisterHandlerData( uintptr_t base, size_t size, size_t num_protected_instructions, const ProtectedInstructionData* protected_instructions); /// Removes the data from the master list and frees any memory, if necessary. /// TODO(mtrofin): We can switch to using size_t for index and not need /// kInvalidIndex. void TH_EXPORT_PRIVATE ReleaseHandlerData(int index); /// Sets the base and size of the V8 sandbox region. If set, these will be used /// by the trap handler: only faulting accesses to memory inside the V8 sandbox /// should be handled by the trap handler since all Wasm memory objects are /// located inside the sandbox. void TH_EXPORT_PRIVATE SetV8SandboxBaseAndSize(uintptr_t base, size_t size); // Initially false, set to true if when trap handlers are enabled. Never goes // back to false then. TH_EXPORT_PRIVATE extern bool g_is_trap_handler_enabled; // Initially true, set to false when either {IsTrapHandlerEnabled} or // {EnableTrapHandler} is called to prevent calling {EnableTrapHandler} // repeatedly, or after {IsTrapHandlerEnabled}. Needs to be atomic because // {IsTrapHandlerEnabled} can be called from any thread. Updated using relaxed // semantics, since it's not used for synchronization. TH_EXPORT_PRIVATE extern std::atomic<bool> g_can_enable_trap_handler; // Enables trap handling for WebAssembly bounds checks. // // use_v8_handler indicates that V8 should install its own handler // rather than relying on the embedder to do it. TH_EXPORT_PRIVATE bool EnableTrapHandler(bool use_v8_handler); // Set the address that the trap handler should continue execution from when it // gets a fault at a recognised address. TH_EXPORT_PRIVATE void SetLandingPad(uintptr_t landing_pad); inline bool IsTrapHandlerEnabled() { … } #if defined(V8_OS_AIX) // `thread_local` does not link on AIX: // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100641 extern __thread int g_thread_in_wasm_code; #else extern thread_local int g_thread_in_wasm_code; #endif // Return the address of the thread-local {g_thread_in_wasm_code} variable. This // pointer can be accessed and modified as long as the thread calling this // function exists. Only use if from the same thread do avoid race conditions. V8_NOINLINE TH_EXPORT_PRIVATE int* GetThreadInWasmThreadLocalAddress(); // On Windows, asan installs its own exception handler which maps shadow // memory. Since our exception handler may be executed before the asan exception // handler, we have to make sure that asan shadow memory is not accessed here. TH_DISABLE_ASAN inline bool IsThreadInWasm() { … } inline void SetThreadInWasm() { … } inline void ClearThreadInWasm() { … } bool RegisterDefaultTrapHandler(); TH_EXPORT_PRIVATE void RemoveTrapHandler(); TH_EXPORT_PRIVATE size_t GetRecoveredTrapCount(); } // namespace trap_handler } // namespace internal } // namespace v8 #endif // V8_TRAP_HANDLER_TRAP_HANDLER_H_
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