Fix Windows Arm64 unwinding (dotnet#102258)

* Fix Windows Arm64 unwinding

There was an issue with unwinding native code functions in case of calls
to no-return function placed at an end of a function code block. The
return address was not in range of the function code, so
RtlLookupFunctionEntry was not finding anything, we were thinking that
it was a leaf function due to that and tried to unwind using LR only,
which was wrong and resulted in staying on the same instruction. Thus
the unwinding ended up in an infinite loop for those cases.
The fix, that matches what RtlUnwind does, is to adjust the instruction
pointer at call sites back. This is arm64 specific.

Close dotnet#101921

* Modify the ifdef from CONTEXT_UNWOUND_TO_CALL to TARGET_ARM64

src/coreclr/inc/clrconfigvalues.h

@@ -259,12 +259,7 @@ RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_legacyCorruptedStateExceptionsPolicy, W("le
 CONFIG_DWORD_INFO(INTERNAL_SuppressLostExceptionTypeAssert, W("SuppressLostExceptionTypeAssert"), 0, "")
 RETAIL_CONFIG_DWORD_INFO(INTERNAL_UseEntryPointFilter, W("UseEntryPointFilter"), 0, "")
 RETAIL_CONFIG_DWORD_INFO(INTERNAL_Corhost_Swallow_Uncaught_Exceptions, W("Corhost_Swallow_Uncaught_Exceptions"), 0, "")
-#if defined(HOST_WINDOWS) && defined(TARGET_ARM64) 
-// disable new exception handling for Windows ARM64
-RETAIL_CONFIG_DWORD_INFO(EXTERNAL_LegacyExceptionHandling, W("LegacyExceptionHandling"), 1, "Enable legacy exception handling.");
-#else
 RETAIL_CONFIG_DWORD_INFO(EXTERNAL_LegacyExceptionHandling, W("LegacyExceptionHandling"), 0, "Enable legacy exception handling.");
-#endif // defined(WINDOWS) && defined(TARGET_ARM64)
 
 ///
 /// Garbage collector

src/coreclr/vm/stackwalk.cpp

@@ -553,6 +553,13 @@ PCODE Thread::VirtualUnwindCallFrame(T_CONTEXT* pContext,
     UINT_PTR            uImageBase;
     PT_RUNTIME_FUNCTION pFunctionEntry;
 
+#if !defined(TARGET_UNIX) && defined(TARGET_ARM64)
+    if ((pContext->ContextFlags & CONTEXT_UNWOUND_TO_CALL) != 0)
+    {
+        uControlPc -= STACKWALK_CONTROLPC_ADJUST_OFFSET;
+    }
+#endif // !TARGET_UNIX && TARGET_ARM64
+
     if (pCodeInfo == NULL)
     {
 #ifndef TARGET_UNIX
@@ -592,7 +599,23 @@ PCODE Thread::VirtualUnwindCallFrame(T_CONTEXT* pContext,
 
     if (pFunctionEntry)
     {
-        uControlPc = VirtualUnwindNonLeafCallFrame(pContext, pContextPointers, pFunctionEntry, uImageBase);
+    #ifdef HOST_64BIT
+        UINT64              EstablisherFrame;
+    #else  // HOST_64BIT
+        DWORD               EstablisherFrame;
+    #endif // HOST_64BIT
+        PVOID               HandlerData;
+
+        RtlVirtualUnwind(0,
+                         uImageBase,
+                         uControlPc,
+                         pFunctionEntry,
+                         pContext,
+                         &HandlerData,
+                         &EstablisherFrame,
+                         pContextPointers);
+
+        uControlPc = GetIP(pContext);
     }
     else
     {
@@ -661,54 +684,6 @@ PCODE Thread::VirtualUnwindLeafCallFrame(T_CONTEXT* pContext)
     return uControlPc;
 }
 
-// static
-PCODE Thread::VirtualUnwindNonLeafCallFrame(T_CONTEXT* pContext, KNONVOLATILE_CONTEXT_POINTERS* pContextPointers,
-    PT_RUNTIME_FUNCTION pFunctionEntry, UINT_PTR uImageBase)
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-        PRECONDITION(CheckPointer(pContext, NULL_NOT_OK));
-        PRECONDITION(CheckPointer(pContextPointers, NULL_OK));
-        PRECONDITION(CheckPointer(pFunctionEntry, NULL_OK));
-    }
-    CONTRACTL_END;
-
-    PCODE           uControlPc = GetIP(pContext);
-#ifdef HOST_64BIT
-    UINT64              EstablisherFrame;
-#else  // HOST_64BIT
-    DWORD               EstablisherFrame;
-#endif // HOST_64BIT
-    PVOID               HandlerData;
-
-    if (NULL == pFunctionEntry)
-    {
-#ifndef TARGET_UNIX
-        pFunctionEntry  = RtlLookupFunctionEntry(uControlPc,
-                                                 ARM_ONLY((DWORD*))(&uImageBase),
-                                                 NULL);
-#endif
-        if (NULL == pFunctionEntry)
-        {
-            return (PCODE)NULL;
-        }
-    }
-
-    RtlVirtualUnwind(0,
-                     uImageBase,
-                     uControlPc,
-                     pFunctionEntry,
-                     pContext,
-                     &HandlerData,
-                     &EstablisherFrame,
-                     pContextPointers);
-
-    uControlPc = GetIP(pContext);
-    return uControlPc;
-}
-
 extern void* g_hostingApiReturnAddress;
 
 // static

src/coreclr/vm/threads.h

@@ -2369,8 +2369,6 @@ class Thread
     static UINT_PTR VirtualUnwindCallFrame(PREGDISPLAY pRD, EECodeInfo * pCodeInfo = NULL);
 #ifndef DACCESS_COMPILE
     static PCODE VirtualUnwindLeafCallFrame(T_CONTEXT* pContext);
-    static PCODE VirtualUnwindNonLeafCallFrame(T_CONTEXT* pContext, T_KNONVOLATILE_CONTEXT_POINTERS* pContextPointers = NULL,
-        PT_RUNTIME_FUNCTION pFunctionEntry = NULL, UINT_PTR uImageBase = 0);
     static UINT_PTR VirtualUnwindToFirstManagedCallFrame(T_CONTEXT* pContext);
 #endif // DACCESS_COMPILE
 #endif // FEATURE_EH_FUNCLETS