Kernel: Move GDT to Processor

2024-03-06 00:02:18 +02:00
parent 8670364f44
commit 58aca68726
6 changed files with 142 additions and 99 deletions
--- a/kernel/include/kernel/GDT.h
+++ b/kernel/include/kernel/GDT.h
@@ -1,16 +1,100 @@
 #pragma once

+#include <BAN/Array.h>
+#include <BAN/NoCopyMove.h>
+
 #include <stdint.h>

-namespace Kernel::GDT
+namespace Kernel
 {

-	static constexpr inline bool is_user_segment(uint8_t segment)
+	struct TaskStateSegment
 	{
-		return (segment & 3) == 3;
-	}
+		uint32_t reserved1;
+		uint64_t rsp0;
+		uint64_t rsp1;
+		uint64_t rsp2;
+		uint64_t reserved2;
+		uint64_t ist1;
+		uint64_t ist2;
+		uint64_t ist3;
+		uint64_t ist4;
+		uint64_t ist5;
+		uint64_t ist6;
+		uint64_t ist7;
+		uint64_t reserved3;
+		uint16_t reserved4;
+		uint16_t iopb;
+	} __attribute__((packed));

-	void initialize();
-	void set_tss_stack(uintptr_t);
+	union SegmentDescriptor
+	{
+		struct
+		{
+			uint16_t	limit1;
+			uint16_t	base1;
+			uint8_t		base2;
+			uint8_t		access;
+			uint8_t		limit2 : 4;
+			uint8_t		flags  : 4;
+			uint8_t		base3;
+		} __attribute__((packed));
+
+		struct
+		{
+			uint32_t low;
+			uint32_t high;
+		} __attribute__((packed));
+
+	} __attribute__((packed));
+
+	struct GDTR
+	{
+		uint16_t size;
+		uint64_t address;
+	} __attribute__((packed));
+
+	class GDT
+	{
+		BAN_NON_COPYABLE(GDT);
+		BAN_NON_MOVABLE(GDT);
+
+	public:
+		static GDT* create();
+
+		static constexpr inline bool is_user_segment(uint8_t segment)
+		{
+			return (segment & 3) == 3;
+		}
+
+		void set_tss_stack(uintptr_t rsp)
+		{
+			m_tss.rsp0 = rsp;
+		}
+
+	private:
+		GDT() = default;
+
+		void write_entry(uint8_t offset, uint32_t base, uint32_t limit, uint8_t access, uint8_t flags);
+		void write_tss();
+
+		void flush_gdt()
+		{
+			asm volatile("lgdt %0" :: "m"(m_gdtr) : "memory");
+		}
+
+		void flush_tss()
+		{
+			asm volatile("ltr %0" :: "rm"((uint16_t)0x28) : "memory");
+		}
+
+	private:
+		BAN::Array<SegmentDescriptor, 7> m_gdt; // null, kernel code, kernel data, user code, user data, tss low, tss high
+		TaskStateSegment m_tss;
+		const GDTR m_gdtr {
+			.size = m_gdt.size() * sizeof(SegmentDescriptor) - 1,
+			.address = reinterpret_cast<uint64_t>(m_gdt.data())
+		};
+	};

 }