Kernel: Add an x86 include check+error in x86/PageFault.h

Author: https://github.com/jamesmintram
Commit: https://github.com/SerenityOS/serenity/commit/eb33df0c30a
Pull-request: https://github.com/SerenityOS/serenity/pull/11141
Reviewed-by: https://github.com/bgianfo ✅
Reviewed-by: https://github.com/kleinesfilmroellchen ✅

Kernel/Arch/x86/PageFault.h

@@ -9,6 +9,9 @@
 #include <AK/Types.h>
 #include <Kernel/VirtualAddress.h>
 
+#include <AK/Platform.h>
+VALIDATE_IS_X86()
+
 namespace Kernel {
 
 struct PageFaultFlags {

Kernel/Arch/x86/common/Interrupts.cpp

@@ -24,6 +24,7 @@
 #include <Kernel/Arch/Processor.h>
 #include <Kernel/Arch/RegisterState.h>
 #include <Kernel/Arch/x86/ISRStubs.h>
+#include <Kernel/Arch/x86/PageFault.h>
 #include <Kernel/Arch/x86/TrapFrame.h>
 #include <Kernel/KSyms.h>
 

Kernel/Memory/MemoryManager.cpp

@@ -7,6 +7,7 @@
 #include <AK/Assertions.h>
 #include <AK/Memory.h>
 #include <AK/StringView.h>
+#include <Kernel/Arch/x86/PageFault.h>
 #include <Kernel/BootInfo.h>
 #include <Kernel/CMOS.h>
 #include <Kernel/FileSystem/Inode.h>

Kernel/Memory/MemoryManager.h

@@ -11,7 +11,6 @@
 #include <AK/NonnullOwnPtrVector.h>
 #include <AK/NonnullRefPtrVector.h>
 #include <AK/String.h>
-#include <Kernel/Arch/x86/PageFault.h>
 #include <Kernel/Arch/x86/TrapFrame.h>
 #include <Kernel/Forward.h>
 #include <Kernel/Locking/Spinlock.h>

Kernel/Memory/Region.cpp

@@ -6,6 +6,7 @@
 
 #include <AK/Memory.h>
 #include <AK/StringView.h>
+#include <Kernel/Arch/x86/PageFault.h>
 #include <Kernel/Debug.h>
 #include <Kernel/FileSystem/Inode.h>
 #include <Kernel/Memory/AnonymousVMObject.h>

Kernel/Memory/Region.h

@@ -9,7 +9,6 @@
 #include <AK/EnumBits.h>
 #include <AK/IntrusiveList.h>
 #include <AK/Weakable.h>
-#include <Kernel/Arch/x86/PageFault.h>
 #include <Kernel/Forward.h>
 #include <Kernel/Heap/SlabAllocator.h>
 #include <Kernel/KString.h>
@@ -18,6 +17,10 @@
 #include <Kernel/Sections.h>
 #include <Kernel/UnixTypes.h>
 
+namespace Kernel {
+class PageFault;
+}
+
 namespace Kernel::Memory {
 
 enum class ShouldFlushTLB {