From bb36ab3656c9d43e5206a4b0a86a7de7b0c4f684 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=A1s=20Ortega=20Froysa?=
 <nortega@themusicinnoise.net>
Date: Thu, 5 Apr 2018 10:23:23 +0200
Subject: [PATCH] Load the TSS.

---
 src/kernel/arch/x86/gdt.c |  7 +++++++
 src/kernel/arch/x86/gdt.h |  1 +
 src/kernel/arch/x86/gdt.s | 10 ++++++++++
 3 files changed, 18 insertions(+)

diff --git a/src/kernel/arch/x86/gdt.c b/src/kernel/arch/x86/gdt.c
index 1914df1..129c20e 100644
--- a/src/kernel/arch/x86/gdt.c
+++ b/src/kernel/arch/x86/gdt.c
@@ -58,9 +58,16 @@ void gdt_install() {
 	// user
 	gdt_entry_set(&gdt[3], 0, 0xFFFFFFFF, 0xFA, 0xCF);
 	gdt_entry_set(&gdt[4], 0, 0xFFFFFFFF, 0xF2, 0xCF);
+
 	// TSS
+	tss.ss0 = 0x10;
+	// TODO: set esp0 for system interrupts
+	tss.iopb = sizeof(tss);
 	gdt_entry_set(&gdt[5], (uint32_t)&tss,
 			sizeof(tss), 0x89, 0x40);
 
 	gdt_flush(&gdtr);
+
+	// load the TSS
+	tss_load();
 }
diff --git a/src/kernel/arch/x86/gdt.h b/src/kernel/arch/x86/gdt.h
index 3581e45..63a33a5 100644
--- a/src/kernel/arch/x86/gdt.h
+++ b/src/kernel/arch/x86/gdt.h
@@ -21,6 +21,7 @@
 #include "structs.h"
 
 extern void gdt_flush(struct segreg *gdtr);
+extern void tss_load();
 void gdt_entry_set(struct segdesc *entry, uint32_t base,
 		uint32_t limit, uint8_t access, uint8_t gran);
 void gdt_install();
diff --git a/src/kernel/arch/x86/gdt.s b/src/kernel/arch/x86/gdt.s
index 85d9acf..f036c72 100644
--- a/src/kernel/arch/x86/gdt.s
+++ b/src/kernel/arch/x86/gdt.s
@@ -35,3 +35,13 @@ gdt_flush:
 gdt_flush_end:
 	popl %ebp
 	ret
+
+.global tss_load
+.type tss_load,@function
+tss_load:
+	pushl %ebp
+	movl %esp, %ebp
+	movw $0x28, %ax
+	ltr %ax
+	popl %ebp
+	ret