From 87956a41a3b143a099d2e03266ada0c714760f09 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicolas=20Hord=C3=A9?= <nicolas@palon.fr>
Date: Tue, 18 Sep 2018 15:11:50 +0200
Subject: [PATCH] feat: gestion TSS/TSR en cours

---
 include/asm.h   |  2 ++
 include/gdt.h   | 35 ++++++++++++++++++++---------------
 lib/gdt.c       | 21 ++++++++++++++++++++-
 lib/syscall.c   | 13 +++++++++++++
 system/system.c |  4 ++++
 5 files changed, 59 insertions(+), 16 deletions(-)

diff --git a/include/asm.h b/include/asm.h
index 4364d8b..ec0a920 100755
--- a/include/asm.h
+++ b/include/asm.h
@@ -36,6 +36,8 @@
 
 #define rdmsr(reg,low,high) asm volatile ("rdmsr" :: "=a" (low), "=d" (high) : "c" (reg) )
 
+#define ltr(tss) asm volatile ("ltr %%ax":: "a" (tss))
+
 /******************************************************************************/
 
 #define outb(port,value) \
diff --git a/include/gdt.h b/include/gdt.h
index 4e041af..f7afc17 100755
--- a/include/gdt.h
+++ b/include/gdt.h
@@ -8,12 +8,13 @@
 #define	SEL_KERNEL_DATA 0x28 /* selecteur data du kernel */
 #define	SEL_USER_DATA 0x30 /* selecteur data utilisateur */
 
+#define	SEL_TSS 0x38 /* selecteur TSR */
+
 #define	STACK_OFFSET 0xFFFF /* adresse de la pile du kernel */
 
-#define SIZEGDT		0x7	/* nombre de descripteurs */
+#define SIZEGDT		0x8	/* nombre de descripteurs */
 #define BASEGDT		0x00000800	/* addr de la GDT */
 
-
 typedef struct gdtdes {
     u16 lim0_15;    
     u16 base0_15;
@@ -29,22 +30,26 @@ struct gdtr {
 	u32 base;
 } __attribute__ ((packed));
 
-struct tss {
-	u16 previous_task, __previous_task_unused;
+typedef struct tss {
+	u16 prevtask, reserved00;
 	u32 esp0;
-	u16 ss0, __ss0_unused;
+	u16 ss0, reserved0;
 	u32 esp1;
-	u16 ss1, __ss1_unused;
+	u16 ss1, reserved1;
 	u32 esp2;
-	u16 ss2, __ss2_unused;
+	u16 ss2, reserved2;
 	u32 cr3;
 	u32 eip, eflags, eax, ecx, edx, ebx, esp, ebp, esi, edi;
-	u16 es, __es_unused;
-	u16 cs, __cs_unused;
-	u16 ss, __ss_unused;
-	u16 ds, __ds_unused;
-	u16 fs, __fs_unused;
-	u16 gs, __gs_unused;
-	u16 ldt_selector, __ldt_sel_unused;
-	u16 debug_flag, io_map;
+	u16 es, reserved3;
+	u16 cs, reserved4;
+	u16 ss, reserved5;
+	u16 ds, reserved6;
+	u16 fs, reserved7;
+	u16 gs, reserved8;
+	u16 ldt_selector, reserved9;
+	u16 trapflag, iomap;
 } __attribute__ ((packed));
+
+void inittr(void);
+void initgdt(u32 offset);
+void makegdtdes(u32 base, u32 limite, u8 acces, u8 flags, gdtdes *desc);
diff --git a/lib/gdt.c b/lib/gdt.c
index 2e9ef8d..780226b 100755
--- a/lib/gdt.c
+++ b/lib/gdt.c
@@ -9,13 +9,16 @@ static struct gdtr gdtreg;
 /* table de GDT */
 static gdtdes gdt[SIZEGDT];
 
+/* TSS */
+static struct tss tss0;
+
 /*******************************************************************************/
 
 /* Initialise la GDT */
 
 void initgdt(u32 offset)
 {
-	makegdtdes(0x0, 0x00000, 0x00, 0x00, &gdt[0]);  /* selecteur nul         */
+	makegdtdes(0x0, 0x00000, 0x00, 0x00, &gdt[0]);  /* descripteur nul         */
 	makegdtdes(0x0, 0xFFFFF, 0x9B, 0x0D, &gdt[1]);	/* code -> SEL_KERNEL_CODE */
 	makegdtdes(0x0, 0x00000, 0x97, 0x0D, &gdt[2]);  /* pile -> SEL_KERNEL_STACK */
 	makegdtdes(0x0, 0xFFFFF, 0xFF, 0x0D, &gdt[3]);	/* code -> SEL_USER_CODE */
@@ -23,6 +26,13 @@ void initgdt(u32 offset)
 	makegdtdes(0x0, 0xFFFFF, 0x93, 0x0D, &gdt[5]);	/* data -> SEL_KERNEL_DATA */
 	makegdtdes(0x0, 0xFFFFF, 0xF3, 0x0D, &gdt[6]);	/* data -> SEL_USER_DATA */
 
+	tss0.trapflag = 0x00;
+	tss0.iomap = 0x00;
+	tss0.esp0 = 0x1FFF0;
+	tss0.ss0 = SEL_TSS;
+
+	makegdtdes(&tss0, 0x67, 0xE9, 0x00, &gdt[7]);	/* descripteur de tss */
+
 	/* initialise le registre gdt */
 	gdtreg.limite = SIZEGDT * 8;
 	gdtreg.base = BASEGDT;
@@ -36,6 +46,15 @@ void initgdt(u32 offset)
 
 /*******************************************************************************/
 
+/* Initialise le registre de tâche (TSR) */
+
+void inittr(void) 
+{
+    ltr(SEL_TSS);
+}
+
+/*******************************************************************************/
+
 /* Initialise les selecteurs avec la GDT */
 
 void initselectors(u32 executingoffset)
diff --git a/lib/syscall.c b/lib/syscall.c
index a10a720..66b17a3 100644
--- a/lib/syscall.c
+++ b/lib/syscall.c
@@ -2,6 +2,19 @@
 #include <gdt.h>  
 #include <asm.h>  
 
+ /* 32bit SYSENTER instruction entry.
+ *
+ * Arguments:
+ * %eax System call number.
+ * %ebx Arg1
+ * %ecx Arg2
+ * %edx Arg3
+ * %esi Arg4
+ * %edi Arg5
+ * %ebp user stack
+ * 0(%ebp) Arg6*/
+
+
 /*******************************************************************************/
 
 /* Entrée pour les appels système SYSENTER */
diff --git a/system/system.c b/system/system.c
index 572307e..0e59404 100755
--- a/system/system.c
+++ b/system/system.c
@@ -56,6 +56,10 @@ int main(void)
 next:
 	ok();
 
+	print("\033[37m\033[0m -Initilisation des taches (TSR)\000");
+    inittr();
+	ok();
+
 	print("\033[37m\033[0m -Initilisation des interruptions (IDT/PIC)\000");
 	initidt();
 	initpic();