From 88f60b5e4106a71216c1ba350bd4650c6215a2d2 Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Sat, 15 Apr 2023 23:53:45 +0300
Subject: [PATCH] Kernel: Map all ACPI tables on initialization

This makes their usage much easier and less error prone

They won't mapped be processes when we get to there, so this won't be
a problem
---
 kernel/include/kernel/ACPI.h |  3 +--
 kernel/kernel/ACPI.cpp       | 21 +++++++++------------
 kernel/kernel/APIC.cpp       | 10 +++-------
 3 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/kernel/include/kernel/ACPI.h b/kernel/include/kernel/ACPI.h
index 29343630..fce4531e 100644
--- a/kernel/include/kernel/ACPI.h
+++ b/kernel/include/kernel/ACPI.h
@@ -84,8 +84,7 @@ namespace Kernel
 		static BAN::ErrorOr<void> initialize();
 		static ACPI& get();
 
-		BAN::ErrorOr<const SDTHeader*> get_header(const char[4]);
-		void unmap_header(const SDTHeader*);
+		const SDTHeader* get_header(const char[4]);
 
 	private:
 		ACPI() = default;
diff --git a/kernel/kernel/ACPI.cpp b/kernel/kernel/ACPI.cpp
index 8880cd0d..ee169fe9 100644
--- a/kernel/kernel/ACPI.cpp
+++ b/kernel/kernel/ACPI.cpp
@@ -135,28 +135,25 @@ namespace Kernel
 
 		MMU::get().allocate_range(m_header_table, m_entry_count * m_entry_size, MMU::Flags::Present);
 
+		for (uint32_t i = 0; i < m_entry_count; i++)
+		{
+			auto* header = get_header_from_index(i);
+			MMU::get().allocate_page((uintptr_t)header, MMU::Flags::Present);
+			MMU::get().allocate_range((uintptr_t)header, header->length, MMU::Flags::Present);
+		}
+
 		return {};
 	}
 
-	BAN::ErrorOr<const ACPI::SDTHeader*> ACPI::get_header(const char signature[4])
+	const ACPI::SDTHeader* ACPI::get_header(const char signature[4])
 	{
 		for (uint32_t i = 0; i < m_entry_count; i++)
 		{
 			const SDTHeader* header = get_header_from_index(i);
-			MMU::get().allocate_range((uintptr_t)header, header->length, MMU::Flags::Present);
 			if (is_valid_std_header(header) && memcmp(header->signature, signature, 4) == 0)
 				return header;
-			unmap_header(header);
 		}
-		return BAN::Error::from_error_code(ErrorCode::ACPI_NoSuchHeader);
-	}
-
-	void ACPI::unmap_header(const ACPI::SDTHeader* header)
-	{
-		// I have to improve MMU page mapping so we can actually unmap
-		// without unmapping other mapped tables
-		(void)header;
-		//MMU::get().unallocate_range((uintptr_t)header, header->length);
+		return nullptr;
 	}
 
 	const ACPI::SDTHeader* ACPI::get_header_from_index(size_t index)
diff --git a/kernel/kernel/APIC.cpp b/kernel/kernel/APIC.cpp
index efd835a6..29e6c602 100644
--- a/kernel/kernel/APIC.cpp
+++ b/kernel/kernel/APIC.cpp
@@ -91,15 +91,13 @@ APIC* APIC::create()
 		return nullptr;
 	}
 
-	auto header_or_error = Kernel::ACPI::get().get_header("APIC");
-	if (header_or_error.is_error())
+	const MADT* madt = (const MADT*)Kernel::ACPI::get().get_header("APIC");
+	if (madt == nullptr)
 	{
-		dprintln("{}", header_or_error.error());
+		dprintln("Could not find MADT header");
 		return nullptr;
 	}
 
-	const MADT* madt = (const MADT*)header_or_error.value();
-
 	APIC* apic = new APIC;
 	apic->m_local_apic = madt->local_apic;
 	for (uint32_t i = 0x00; i <= 0xFF; i++)
@@ -139,8 +137,6 @@ APIC* APIC::create()
 		madt_entry_addr += entry->length;
 	}
 
-	Kernel::ACPI::get().unmap_header(madt);
-
 	if (apic->m_local_apic == 0 || apic->m_io_apics.empty())
 	{
 		dprintln("MADT did not provide necessary information");