Kernel: Implement poweroff with my AML interpreter

This can succesfully poweroff qemu!

kernel/include/kernel/ACPI/ACPI.h

@@ -22,6 +22,10 @@ namespace Kernel::ACPI
 		//   2: SAPIC
 		BAN::ErrorOr<void> enter_acpi_mode(uint8_t mode);
 
+		// This function will power off the system
+		// This function will return only if there was an error
+		void poweroff();
+
 	private:
 		ACPI() = default;
 		BAN::ErrorOr<void> initialize_impl();

kernel/include/kernel/ACPI/AML/NamedObject.h

@@ -22,6 +22,13 @@ namespace Kernel::ACPI::AML
 			: NamedObject(Node::Type::Name, name), object(BAN::move(object))
 		{}
 
+		BAN::RefPtr<AML::Node> evaluate() override
+		{
+			if (!object)
+				return {};
+			return object->evaluate();
+		}
+
 		static ParseResult parse(ParseContext& context);
 		virtual void debug_print(int indent) const override;
 	};

kernel/include/kernel/ACPI/AML/Package.h

@@ -14,6 +14,25 @@ namespace Kernel::ACPI::AML
 
 		Package() : Node(Node::Type::Package) {}
 
+		BAN::RefPtr<AML::Node> evaluate() override
+		{
+			BAN::Vector<BAN::RefPtr<AML::Node>> evaluated_elements;
+			for (auto& element : elements)
+			{
+				auto evaluated = element->evaluate();
+				if (!evaluated)
+				{
+					AML_ERROR("Failed to evaluate element in package");
+					return {};
+				}
+				evaluated_elements.push_back(evaluated);
+			}
+
+			auto package = MUST(BAN::RefPtr<Package>::create());
+			package->elements = BAN::move(evaluated_elements);
+			return package;
+		}
+
 		static ParseResult parse(AML::ParseContext& context)
 		{
 			ASSERT(context.aml_data.size() >= 1);