From 043b8b9d4624d4208a330cbce9775c43f1bf1fc6 Mon Sep 17 00:00:00 2001
From: Vegard Storheil Eriksen <zyp@jvnv.net>
Date: Wed, 20 Jan 2010 22:19:56 +0100
Subject: Added TSS.

---
 kernel/gdt.c | 10 +++++++++-
 kernel/gdt.h | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/kernel/gdt.c b/kernel/gdt.c
index 7d23289..92d3d4c 100644
--- a/kernel/gdt.c
+++ b/kernel/gdt.c
@@ -1,11 +1,14 @@
 #include "gdt.h"
 
+tss_entry tss = tss_entry_init(0xfffff800, 0x10, 0x0b, 0x13);
+
 gdt_entry gdt[] = {
 	gdt_entry_init(0, 0, 0),
 	gdt_entry_init(0, 0xfffff, 0xc09a), // Code segment.
 	gdt_entry_init(0, 0xfffff, 0xc092), // Data segment.
 	gdt_entry_init(0, 0xfffff, 0xc0fa), // User mode code segment.
 	gdt_entry_init(0, 0xfffff, 0xc0f2), // User mode data segment.
+	gdt_entry_init(0, sizeof(tss_entry), 0x00e9), // TSS.
 };
 
 gdt_ptr gdtr = {
@@ -14,6 +17,10 @@ gdt_ptr gdtr = {
 };
 
 void gdt_init() {
+	gdt[5].base_low = (uint32_t)&tss & 0xffff;
+	gdt[5].base_mid = (uint32_t)&tss >> 16 & 0xff;
+	gdt[5].base_high = (uint32_t)&tss >> 24 & 0xff;
+	
 	asm volatile(
 		"lgdt (%0)\n"
 		"mov %w1, %%ds\n"
@@ -23,6 +30,7 @@ void gdt_init() {
 		"mov %w1, %%ss\n"
 		"ljmp $0x08, $.flush\n"
 		".flush:\n"
-		: : "r" (&gdtr), "r" (0x10)
+		"ltr %w2\n"
+		: : "r" (&gdtr), "r" (0x10), "r" (0x28)
 	);
 }
diff --git a/kernel/gdt.h b/kernel/gdt.h
index e2c5b46..36c37dd 100644
--- a/kernel/gdt.h
+++ b/kernel/gdt.h
@@ -3,6 +3,45 @@
 
 #include "types.h"
 
+typedef struct {
+	uint32_t link;
+	
+	uint32_t esp0;
+	uint32_t ss0;
+	
+	uint32_t esp1;
+	uint32_t ss1;
+	
+	uint32_t esp2;
+	uint32_t ss2;
+	
+	uint32_t cr3;
+	
+	uint32_t eip;
+	uint32_t eflags;
+	
+	uint32_t eax;
+	uint32_t ecx;
+	uint32_t edx;
+	uint32_t ebx;
+	uint32_t esp;
+	uint32_t ebp;
+	uint32_t esi;
+	uint32_t edi;
+	
+	uint32_t es;
+	uint32_t cs;
+	uint32_t ss;
+	uint32_t ds;
+	uint32_t fs;
+	uint32_t gs;
+	
+	uint32_t ldt;
+	
+	uint16_t trap;
+	uint16_t iomap;
+} __attribute__((packed)) tss_entry;
+
 typedef struct {
 	uint16_t limit_low;
 	uint16_t base_low;
@@ -23,6 +62,16 @@ typedef struct {
 	.limit_low = (l & 0xffff), \
 	.flags = (f | (l >> 8 & 0x0f00))}
 
+#define tss_entry_init(e, s, c, d) { \
+	.esp0 = e, \
+	.ss0 = s, \
+	.cs = c, \
+	.ss = d, \
+	.ds = d, \
+	.es = d, \
+	.fs = d, \
+	.gs = d}
+
 void gdt_init();
 
 #endif
-- 
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