Use QueueUserAPC2 for EE suspension on CoreCLR win-arm64.

src/coreclr/clrdefinitions.cmake

@@ -223,7 +223,7 @@ if (NOT CLR_CMAKE_TARGET_ARCH_I386 OR NOT CLR_CMAKE_TARGET_WIN32)
   add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:FEATURE_EH_FUNCLETS>)
 endif (NOT CLR_CMAKE_TARGET_ARCH_I386 OR NOT CLR_CMAKE_TARGET_WIN32)
 
-if (CLR_CMAKE_TARGET_WIN32 AND CLR_CMAKE_TARGET_ARCH_AMD64)
+if (CLR_CMAKE_TARGET_WIN32 AND (CLR_CMAKE_TARGET_ARCH_AMD64 OR CLR_CMAKE_TARGET_ARCH_ARM64))
   add_definitions(-DFEATURE_SPECIAL_USER_MODE_APC)
 endif()
 

src/coreclr/debug/ee/debugger.cpp

@@ -971,7 +971,7 @@ Debugger::Debugger()
     m_mdDataStructureVersion = 1;
     m_fOutOfProcessSetContextEnabled =
 #if defined(OUT_OF_PROCESS_SETTHREADCONTEXT) && !defined(DACCESS_COMPILE)
-        Thread::AreCetShadowStacksEnabled() || CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_OutOfProcessSetContext) != 0;
+        Thread::AreShadowStacksEnabled() || CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_OutOfProcessSetContext) != 0;
 #else
         FALSE;
 #endif

src/coreclr/vm/amd64/RedirectedHandledJITCase.asm

@@ -217,7 +217,8 @@ NESTED_ENTRY ApcActivationCallbackStub, _TEXT, FixRedirectContextHandler
     .errnz REDIRECTSTUB_ESTABLISHER_OFFSET_RBP, REDIRECTSTUB_ESTABLISHER_OFFSET_RBP has changed - update asm stubs
         END_PROLOGUE
 
-        ; Save the pointer to the interrupted context on the stack for the stack walker
+        ; Save a copy of the redirect CONTEXT*.
+        ; This is needed for the debugger to unwind the stack.
         mov             rax, [rcx + OFFSETOF__APC_CALLBACK_DATA__ContextRecord]
         mov             [rbp + 20h], rax
     .errnz REDIRECTSTUB_RBP_OFFSET_CONTEXT - 20h, REDIRECTSTUB_RBP_OFFSET_CONTEXT has changed - update asm stubs

src/coreclr/vm/arm64/asmconstants.h

@@ -157,6 +157,9 @@ ASMCONSTANTS_C_ASSERT(UnmanagedToManagedFrame__m_pvDatum == offsetof(UnmanagedTo
 
 #endif // FEATURE_COMINTEROP
 
+#ifdef FEATURE_SPECIAL_USER_MODE_APC
+#define OFFSETOF__APC_CALLBACK_DATA__ContextRecord 0x8
+#endif
 
 #define REDIRECTSTUB_SP_OFFSET_CONTEXT 0
 

src/coreclr/vm/arm64/asmhelpers.asm

@@ -1174,5 +1174,39 @@ __HelperNakedFuncName SETS "$helper":CC:"Naked"
         br x9
     LEAF_END
 
+#ifdef FEATURE_SPECIAL_USER_MODE_APC
+
+    IMPORT |?ApcActivationCallback@Thread@@CAX_K@Z|
+
+    ; extern "C" void NTAPI ApcActivationCallbackStub(ULONG_PTR Parameter);
+    NESTED_ENTRY ApcActivationCallbackStub
+
+        PROLOG_SAVE_REG_PAIR    fp, lr, #-16!
+        PROLOG_STACK_ALLOC      16                ; stack slot for CONTEXT* and padding
+
+        ;REDIRECTSTUB_SP_OFFSET_CONTEXT is defined in asmconstants.h and is used in GetCONTEXTFromRedirectedStubStackFrame
+        ;If CONTEXT is not saved at 0 offset from SP it must be changed as well.
+        ASSERT REDIRECTSTUB_SP_OFFSET_CONTEXT == 0
+
+        ; Save a copy of the redirect CONTEXT*.
+        ; This is needed for the debugger to unwind the stack.
+        ldr x17, [x0, OFFSETOF__APC_CALLBACK_DATA__ContextRecord]
+        str x17, [sp]
+
+        bl |?ApcActivationCallback@Thread@@CAX_K@Z|
+
+        EPILOG_STACK_FREE       16                ; undo stack slot for CONTEXT* and padding
+        EPILOG_RESTORE_REG_PAIR fp, lr, #16!
+        EPILOG_RETURN
+
+; Put a label here to tell the debugger where the end of this function is.
+    PATCH_LABEL ApcActivationCallbackStubEnd
+    EXPORT ApcActivationCallbackStubEnd
+
+    NESTED_END
+
+#endif ; FEATURE_SPECIAL_USER_MODE_APC
+
+
 ; Must be at very end of file
     END

src/coreclr/vm/excep.cpp

@@ -6767,12 +6767,19 @@ VEH_ACTION WINAPI CLRVectoredExceptionHandler(PEXCEPTION_POINTERS pExceptionInfo
 
     if (pExceptionInfo->ExceptionRecord->ExceptionCode == STATUS_RETURN_ADDRESS_HIJACK_ATTEMPT)
     {
+        if (pThread == NULL || !pThread->PreemptiveGCDisabled())
+        {
+            // We are not running managed code, so this cannot be our hijack
+            // Perhaps some other runtime is responsible.
+            return VEH_CONTINUE_SEARCH;
+        }
+
         HijackArgs hijackArgs;
         hijackArgs.Rax = pExceptionInfo->ContextRecord->Rax;
         hijackArgs.Rsp = pExceptionInfo->ContextRecord->Rsp;
 
-        bool areCetShadowStacksEnabled = Thread::AreCetShadowStacksEnabled();
-        if (areCetShadowStacksEnabled)
+        bool areShadowStacksEnabled = Thread::AreShadowStacksEnabled();
+        if (areShadowStacksEnabled)
         {
             // When the CET is enabled, the return address is still on stack, so we need to set the Rsp as
             // if it was popped.
@@ -6790,7 +6797,7 @@ VEH_ACTION WINAPI CLRVectoredExceptionHandler(PEXCEPTION_POINTERS pExceptionInfo
         #undef CALLEE_SAVED_REGISTER
         pExceptionInfo->ContextRecord->Rax = hijackArgs.Rax;
 
-        if (areCetShadowStacksEnabled)
+        if (areShadowStacksEnabled)
         {
             // The context refers to the return instruction
             // Set the return address on the stack to the original one

src/coreclr/vm/jithelpers.cpp

@@ -5282,7 +5282,7 @@ void JIT_Patchpoint(int* counter, int ilOffset)
         DWORD contextSize = 0;
         ULONG64 xStateCompactionMask = 0;
         DWORD contextFlags = CONTEXT_FULL;
-        if (Thread::AreCetShadowStacksEnabled())
+        if (Thread::AreShadowStacksEnabled())
         {
             xStateCompactionMask = XSTATE_MASK_CET_U;
             contextFlags |= CONTEXT_XSTATE;
@@ -5310,7 +5310,7 @@ void JIT_Patchpoint(int* counter, int ilOffset)
         RtlCaptureContext(pFrameContext);
 
 #if defined(TARGET_WINDOWS) && defined(TARGET_AMD64)
-        if (Thread::AreCetShadowStacksEnabled())
+        if (Thread::AreShadowStacksEnabled())
         {
             pFrameContext->ContextFlags |= CONTEXT_XSTATE;
             SetXStateFeaturesMask(pFrameContext, xStateCompactionMask);

src/coreclr/vm/threads.cpp

@@ -8198,8 +8198,8 @@ void Thread::StaticInitialize()
 #ifdef FEATURE_SPECIAL_USER_MODE_APC
     InitializeSpecialUserModeApc();
 
-    // When CET shadow stacks are enabled, support for special user-mode APCs with the necessary functionality is required
-    _ASSERTE_ALL_BUILDS(!AreCetShadowStacksEnabled() || UseSpecialUserModeApc());
+    // When shadow stacks are enabled, support for special user-mode APCs with the necessary functionality is required
+    _ASSERTE_ALL_BUILDS(!AreShadowStacksEnabled() || UseSpecialUserModeApc());
 #endif
 }
 

src/coreclr/vm/threads.h

@@ -4017,15 +4017,20 @@ class Thread
 public:
     static void StaticInitialize();
 
-#if defined(TARGET_AMD64) && defined(TARGET_WINDOWS)
-    static bool AreCetShadowStacksEnabled()
+#if defined(TARGET_WINDOWS)
+    static bool AreShadowStacksEnabled()
     {
         LIMITED_METHOD_CONTRACT;
 
+#if defined(TARGET_AMD64)
         // The SSP is null when CET shadow stacks are not enabled. On processors that don't support shadow stacks, this is a
         // no-op and the intrinsic returns 0. CET shadow stacks are enabled or disabled for all threads, so the result is the
         // same from any thread.
         return _rdsspq() != 0;
+#else
+        // When implementing AreShadowStacksEnabled() on other architectures, review all the places where this is used.
+        return false;
+#endif
     }
 #endif
 

src/coreclr/vm/threadsuspend.cpp

@@ -25,7 +25,7 @@ CLREvent* ThreadSuspend::g_pGCSuspendEvent = NULL;
 
 ThreadSuspend::SUSPEND_REASON ThreadSuspend::m_suspendReason;
 
-#if defined(TARGET_WINDOWS) && defined(TARGET_AMD64)
+#if defined(TARGET_WINDOWS)
 void* ThreadSuspend::g_returnAddressHijackTarget = NULL;
 #endif
 
@@ -4747,13 +4747,13 @@ void Thread::HijackThread(ReturnKind returnKind, ExecutionState *esb)
 
     VOID *pvHijackAddr = reinterpret_cast<VOID *>(OnHijackTripThread);
 
-#if defined(TARGET_WINDOWS) && defined(TARGET_AMD64)
+#if defined(TARGET_WINDOWS)
     void* returnAddressHijackTarget = ThreadSuspend::GetReturnAddressHijackTarget();
     if (returnAddressHijackTarget != NULL)
     {
         pvHijackAddr = returnAddressHijackTarget;
     }
-#endif // TARGET_WINDOWS && TARGET_AMD64
+#endif // TARGET_WINDOWS
 
 #ifdef TARGET_X86
     if (returnKind == RT_Float)
@@ -6062,22 +6062,20 @@ void ThreadSuspend::Initialize()
 #ifdef FEATURE_HIJACK
 #if defined(TARGET_UNIX)
     ::PAL_SetActivationFunction(HandleSuspensionForInterruptedThread, CheckActivationSafePoint);
-#elif defined(TARGET_WINDOWS) && defined(TARGET_AMD64)
-    // Only versions of Windows that have the special user mode APC have a correct implementation of the return address hijack handling
-    if (Thread::UseSpecialUserModeApc())
+#elif defined(TARGET_WINDOWS)
+    if (Thread::AreShadowStacksEnabled())
     {
         HMODULE hModNtdll = WszLoadLibrary(W("ntdll.dll"));
         if (hModNtdll != NULL)
         {
-            typedef ULONG_PTR (NTAPI *PFN_RtlGetReturnAddressHijackTarget)();
-            PFN_RtlGetReturnAddressHijackTarget pfnRtlGetReturnAddressHijackTarget = (PFN_RtlGetReturnAddressHijackTarget)GetProcAddress(hModNtdll, "RtlGetReturnAddressHijackTarget");
-            if (pfnRtlGetReturnAddressHijackTarget != NULL)
-            {
-                g_returnAddressHijackTarget = (void*)pfnRtlGetReturnAddressHijackTarget();
-            }
+            g_returnAddressHijackTarget = (void*)GetProcAddress(hModNtdll, "RtlGetReturnAddressHijackTarget");
+        }
+        if (g_returnAddressHijackTarget == NULL)
+        {
+            _ASSERTE_ALL_BUILDS(!"RtlGetReturnAddressHijackTarget must provide a target when shadow stacks are enabled");
         }
     }
-#endif // TARGET_WINDOWS && TARGET_AMD64
+#endif // TARGET_WINDOWS
 #endif // FEATURE_HIJACK
 }
 

src/coreclr/vm/threadsuspend.h

@@ -194,9 +194,9 @@ class ThreadSuspend
 private:
     static CLREvent * g_pGCSuspendEvent;
 
-#if defined(TARGET_WINDOWS) && defined(TARGET_AMD64)
+#if defined(TARGET_WINDOWS)
     static void* g_returnAddressHijackTarget;
-#endif // TARGET_WINDOWS && TARGET_AMD64
+#endif // TARGET_WINDOWS
 
     // This is true iff we're currently in the process of suspending threads.  Once the
     // threads have been suspended, this is false.  This is set via an instance of
@@ -251,12 +251,12 @@ class ThreadSuspend
         return g_pSuspensionThread;
     }
 
-#if defined(TARGET_WINDOWS) && defined(TARGET_AMD64)
+#if defined(TARGET_WINDOWS)
     static void* GetReturnAddressHijackTarget()
     {
         return g_returnAddressHijackTarget;
     }
-#endif // TARGET_WINDOWS && TARGET_AMD64
+#endif // TARGET_WINDOWS
 
 private:
     static LONG m_DebugWillSyncCount;