Improve Windows page fault handler.

- Re-throw exception if not access violation exception.
- If pointer is not within known pointers also re-throw.

Change-Id: I01461f550994e32c9e8757b0344e70f2195612fb
Signed-off-by: Mrozek, Michal <michal.mrozek@intel.com>

core/page_fault_manager/windows/cpu_page_fault_manager_windows.cpp

@@ -18,10 +18,14 @@ std::function<LONG(struct _EXCEPTION_POINTERS *exceptionInfo)> PageFaultManagerW
 
 PageFaultManagerWindows::PageFaultManagerWindows() {
     pageFaultHandler = [&](struct _EXCEPTION_POINTERS *exceptionInfo) {
-        if (exceptionInfo->ExceptionRecord->ExceptionCode == EXCEPTION_ACCESS_VIOLATION && !this->verifyPageFault(reinterpret_cast<void *>(exceptionInfo->ExceptionRecord->ExceptionInformation[1]))) {
+        if (exceptionInfo->ExceptionRecord->ExceptionCode == EXCEPTION_ACCESS_VIOLATION) {
-            return EXCEPTION_CONTINUE_SEARCH;
+            if (this->verifyPageFault(reinterpret_cast<void *>(exceptionInfo->ExceptionRecord->ExceptionInformation[1]))) {
+                //this is our fault that we serviced, continue app execution
+                return EXCEPTION_CONTINUE_EXECUTION;
+            }
         }
-        return EXCEPTION_CONTINUE_EXECUTION;
+        //not our exception
+        return EXCEPTION_CONTINUE_SEARCH;
     };
 
     previousHandler = AddVectoredExceptionHandler(1, pageFaultHandlerWrapper);

core/unit_tests/page_fault_manager/mock_cpu_page_fault_manager.h

@@ -69,9 +69,10 @@ class MockPageFaultManagerHandlerInvoke : public T {
         if (allowCPUMemoryAccessOnPageFault) {
             this->allowCPUMemoryAccess(ptr, size);
         }
-        return true;
+        return returnStatus;
     }
 
+    bool returnStatus = true;
     bool allowCPUMemoryAccessOnPageFault = false;
     bool handlerInvoked = false;
     size_t size = 65536;

core/unit_tests/page_fault_manager/windows/cpu_page_fault_manager_windows_tests.cpp

@@ -14,14 +14,37 @@
 using namespace NEO;
 using MockPageFaultManagerWindows = MockPageFaultManagerHandlerInvoke<PageFaultManagerWindows>;
 
+bool raiseException(NTSTATUS type) {
+    __try {
+        RaiseException(type, 0, 0, NULL);
+    } __except (EXCEPTION_EXECUTE_HANDLER) {
+        return true;
+    }
+    return false;
+}
+
 TEST(PageFaultManagerWindowsTest, whenPageFaultIsRaisedThenHandlerIsInvoked) {
     auto pageFaultManager = std::make_unique<MockPageFaultManagerWindows>();
     EXPECT_FALSE(pageFaultManager->handlerInvoked);
-
+    EXPECT_FALSE(raiseException(EXCEPTION_ACCESS_VIOLATION));
-    RaiseException(EXCEPTION_ACCESS_VIOLATION, 0, 0, NULL);
     EXPECT_TRUE(pageFaultManager->handlerInvoked);
 }
 
+TEST(PageFaultManagerWindowsTest, whenExceptionAccessViolationIsRaisedButPointerIsNotKnownThenExceptionIsRethrown) {
+    auto pageFaultManager = std::make_unique<MockPageFaultManagerWindows>();
+    EXPECT_FALSE(pageFaultManager->handlerInvoked);
+    pageFaultManager->returnStatus = false;
+    EXPECT_TRUE(raiseException(EXCEPTION_ACCESS_VIOLATION));
+    EXPECT_TRUE(pageFaultManager->handlerInvoked);
+}
+
+TEST(PageFaultManagerWindowsTest, whenExceptionOtherThanAccessViolationIsRaisedThenExceptionIsRethrownAndHandlerIsNotInvoked) {
+    auto pageFaultManager = std::make_unique<MockPageFaultManagerWindows>();
+    EXPECT_FALSE(pageFaultManager->handlerInvoked);
+    EXPECT_TRUE(raiseException(EXCEPTION_DATATYPE_MISALIGNMENT));
+    EXPECT_FALSE(pageFaultManager->handlerInvoked);
+}
+
 TEST(PageFaultManagerWindowsTest, givenProtectedMemoryWhenTryingToAccessThenPageFaultIsRaisedAndMemoryIsAccessibleAfterHandling) {
     auto pageFaultManager = std::make_unique<MockPageFaultManagerWindows>();
     pageFaultManager->allowCPUMemoryAccessOnPageFault = true;