From 45b9dc8be942375ef03d7c2e9e055695d742d34f Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Wed, 17 Apr 2024 02:19:35 +0300
Subject: [PATCH] Kernel: Make ACPI \\_OSI return true for Linux

---
 kernel/include/kernel/ACPI/AML/Method.h | 31 +++++++++++++++----------
 kernel/kernel/ACPI/AML/Namespace.cpp    | 17 ++++++++++----
 2 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/kernel/include/kernel/ACPI/AML/Method.h b/kernel/include/kernel/ACPI/AML/Method.h
index b043ee8a..258ab9c2 100644
--- a/kernel/include/kernel/ACPI/AML/Method.h
+++ b/kernel/include/kernel/ACPI/AML/Method.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <BAN/Function.h>
 #include <kernel/ACPI/AML/Bytes.h>
 #include <kernel/ACPI/AML/Namespace.h>
 #include <kernel/ACPI/AML/ParseContext.h>
@@ -16,6 +17,7 @@ namespace Kernel::ACPI::AML
 		bool serialized;
 		uint8_t sync_level;
 
+		BAN::Function<BAN::RefPtr<AML::Node>(ParseContext&)> override_function;
 		BAN::ConstByteSpan term_list;
 
 		Method(AML::NameSeg name, uint8_t arg_count, bool serialized, uint8_t sync_level)
@@ -117,21 +119,26 @@ namespace Kernel::ACPI::AML
 			AML_DEBUG_PRINTLN("Evaluating {}", scope);
 #endif
 
-
 			BAN::Optional<BAN::RefPtr<AML::Node>> return_value = BAN::RefPtr<AML::Node>();
-			while (context.aml_data.size() > 0)
+
+			if (override_function)
+				return_value = override_function(context);
+			else
 			{
-				auto parse_result = AML::parse_object(context);
-				if (parse_result.returned())
+				while (context.aml_data.size() > 0)
 				{
-					return_value = parse_result.node();
-					break;
-				}
-				if (!parse_result.success())
-				{
-					AML_ERROR("Method {} evaluate failed", scope);
-					return_value = {};
-					break;
+					auto parse_result = AML::parse_object(context);
+					if (parse_result.returned())
+					{
+						return_value = parse_result.node();
+						break;
+					}
+					if (!parse_result.success())
+					{
+						AML_ERROR("Method {} evaluate failed", scope);
+						return_value = {};
+						break;
+					}
 				}
 			}
 
diff --git a/kernel/kernel/ACPI/AML/Namespace.cpp b/kernel/kernel/ACPI/AML/Namespace.cpp
index a86ffff2..47dba7d1 100644
--- a/kernel/kernel/ACPI/AML/Namespace.cpp
+++ b/kernel/kernel/ACPI/AML/Namespace.cpp
@@ -4,6 +4,7 @@
 #include <kernel/ACPI/AML/Namespace.h>
 #include <kernel/ACPI/AML/ParseContext.h>
 #include <kernel/ACPI/AML/Region.h>
+#include <kernel/ACPI/AML/String.h>
 #include <kernel/Lock/LockGuard.h>
 
 namespace Kernel::ACPI
@@ -211,11 +212,19 @@ namespace Kernel::ACPI
 		ADD_PREDEFIED_NAMESPACE("_TZ"sv);
 #undef ADD_PREDEFIED_NAMESPACE
 
-		// Add dummy \_OSI
-		MUST(s_osi_aml_data.push_back(static_cast<uint8_t>(Byte::ReturnOp)));
-		MUST(s_osi_aml_data.push_back(static_cast<uint8_t>(Byte::ZeroOp)));
+		// Add \_OSI that returns true for Linux compatibility
 		auto osi = MUST(BAN::RefPtr<AML::Method>::create(NameSeg("_OSI"sv), 1, false, 0));
-		osi->term_list = s_osi_aml_data.span();
+		osi->override_function = [](AML::ParseContext& context) -> BAN::RefPtr<AML::Node> {
+			ASSERT(context.method_args[0]);
+			auto arg = context.method_args[0]->evaluate();
+			if (!arg || arg->type != AML::Node::Type::String)
+			{
+				AML_ERROR("Invalid _OSI argument");
+				return {};
+			}
+			auto string = static_cast<AML::String*>(arg.ptr());
+			return string->string == "Linux" ? AML::Integer::Constants::Ones : AML::Integer::Constants::Zero;
+		};
 		ASSERT(s_root_namespace->add_named_object(context, AML::NameString("\\_OSI"), osi));
 
 		return s_root_namespace;