1 files changed, 68 insertions, 0 deletions
diff --git a/kernel/inc/drivers/gdt.h b/kernel/inc/drivers/gdt.h
new file mode 100644
index 0000000..7b9c65a
--- /dev/null
+++ b/kernel/inc/drivers/gdt.h
@@ -0,0 +1,68 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+
+#ifndef GDT_H
+#define GDT_H
+
+#include <def.h>
+
+#define GDT_ROOT_CODE_GATE 1
+#define GDT_ROOT_DATA_GATE 2
+#define GDT_USER_CODE_GATE 3
+#define GDT_USER_DATA_GATE 4
+#define GDT_TSS_GATE 5
+
+#define GDT_SUPER_CODE_OFFSET (gdt_offset(GDT_ROOT_CODE_GATE))
+#define GDT_SUPER_DATA_OFFSET (gdt_offset(GDT_ROOT_DATA_GATE))
+#define GDT_USER_CODE_OFFSET (gdt_offset(GDT_USER_CODE_GATE) | 3)
+#define GDT_USER_DATA_OFFSET (gdt_offset(GDT_USER_DATA_GATE) | 3)
+#define GDT_TSS_OFFSET (gdt_offset(GDT_TSS_GATE))
+
+struct gdt_entry {
+	u16 limit_low;
+	u16 base_low;
+	u8 base_middle;
+	u8 access;
+	u8 granularity;
+	u8 base_high;
+} PACKED;
+
+struct gdt_ptr {
+	u16 limit;
+	void *base;
+} PACKED;
+
+struct tss_entry {
+	u32 prev_tss;
+	u32 esp0;
+	u32 ss0;
+	u32 esp1;
+	u32 ss1;
+	u32 esp2;
+	u32 ss2;
+	u32 cr3;
+	u32 eip;
+	u32 eflags;
+	u32 eax;
+	u32 ecx;
+	u32 edx;
+	u32 ebx;
+	u32 esp;
+	u32 ebp;
+	u32 esi;
+	u32 edi;
+	u32 es;
+	u32 cs;
+	u32 ss;
+	u32 ds;
+	u32 fs;
+	u32 gs;
+	u32 ldt;
+	u16 trap;
+	u16 iomap_base;
+} PACKED;
+
+CONST u8 gdt_offset(u8 gate);
+void gdt_install(u32 esp);
+void tss_set_stack(u32 esp);
+
+#endif