From f63afbb3b1c6ab8e8bd81042e4d53776ca171855 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Lov=C3=A9n?= <thomasloven@gmail.com>
Date: Sat, 26 Nov 2016 13:20:57 +0100
Subject: [PATCH] [USER] TSS

---
 kernel/arch/gdt.c       |  8 ++++++--
 kernel/arch/registers.S |  6 ++++++
 kernel/boot/kmain.c     | 13 -------------
 kernel/cpu/cpu.c        |  5 ++---
 kernel/include/cpu.h    |  3 ++-
 kernel/include/gdt.h    | 26 ++++++++++++++++++++++++++
 6 files changed, 42 insertions(+), 19 deletions(-)

diff --git a/kernel/arch/gdt.c b/kernel/arch/gdt.c
index c7729a4..1024565 100644
--- a/kernel/arch/gdt.c
+++ b/kernel/arch/gdt.c
@@ -1,4 +1,5 @@
 #include <gdt.h>
+#include <cpu.h>
 #include <stdint.h>
 #include <debug.h>
 #include <cpu.h>
@@ -10,16 +11,19 @@
 void gdt_init()
 {
   cpu_t *cpu = get_cpu();
+  cpu->tss.io_mba = sizeof(tss_t);
 
   GDT[0] = 0;
   GDT[SEG_KCODE/8] = (uint64_t)(GDT_PRESENT | GDT_CODEDATA | GDT_WRITE | GDT_EXECUTE | GDT_64BIT);
   GDT[SEG_KDATA/8] = (GDT_PRESENT | GDT_CODEDATA | GDT_WRITE);
   GDT[SEG_UCODE/8] = (GDT_PRESENT | GDT_CODEDATA | GDT_WRITE | GDT_EXECUTE | GDT_64BIT | GDT_RING3);
   GDT[SEG_UDATA/8] = (GDT_PRESENT | GDT_CODEDATA | GDT_WRITE | GDT_RING3);
+  GDT[SEG_TSS/8] = (GDT_PRESENT | GDT_TSS | TSS_BLO((uint64_t)&cpu->tss) | TSS_LIM(sizeof(tss_t)));
+  GDT[SEG_TSS/8 + 1] = (TSS_BHI((uint64_t)&cpu->tss));
 
-  GDTP.len = 5*8-1;
+  GDTP.len = 7*8-1;
   GDTP.addr = (uint64_t)&GDT[0];
 
   load_gdt(&GDTP);
-
+  load_tr(SEG_TSS);
 }
diff --git a/kernel/arch/registers.S b/kernel/arch/registers.S
index ca3fa1e..9480b66 100644
--- a/kernel/arch/registers.S
+++ b/kernel/arch/registers.S
@@ -1,3 +1,4 @@
+#include <mem.h>
 .intel_syntax noprefix
 #include <gdt.h>
 
@@ -41,3 +42,8 @@ load_gdt:
 .load_gdt:
   ret
 
+.global load_tr
+load_tr:
+  mov rax, rdi
+  ltr ax
+  ret
diff --git a/kernel/boot/kmain.c b/kernel/boot/kmain.c
index 0ac14c7..c31875f 100644
--- a/kernel/boot/kmain.c
+++ b/kernel/boot/kmain.c
@@ -30,22 +30,9 @@ int kmain(uint64_t multiboot_magic, void *multiboot_data)
   pit_init();
 
   process_t *p1 = process_spawn(0);
-
   thread_t *t1 = new_thread(thread_function);
   process_attach(p1, t1);
 
-  scheduler_insert(t1);
-  t1 = new_thread(thread_function);
-  process_attach(p1, t1);
-  scheduler_insert(t1);
-  t1 = new_thread(thread_function);
-  process_attach(p1, t1);
-  scheduler_insert(t1);
-  t1 = new_thread(thread_function);
-  process_attach(p1, t1);
-  scheduler_insert(t1);
-  t1 = new_thread(thread_function);
-  process_attach(p1, t1);
   scheduler_insert(t1);
 
   asm("sti");
diff --git a/kernel/cpu/cpu.c b/kernel/cpu/cpu.c
index 0e7bf34..ea451e8 100644
--- a/kernel/cpu/cpu.c
+++ b/kernel/cpu/cpu.c
@@ -62,9 +62,8 @@ void cpu_init()
   all_ap_started = 1;
 
   vmm_set_page(0, TRAMPOLINE_ADDR, 0, 0);
-  // Keep the GDT mapped for now
-  /* vmm_set_page(0, TRAMPOLINE_GDT, 0, 0); */
-  /* pmm_free(page); */
+  vmm_set_page(0, TRAMPOLINE_GDT, 0, 0);
+  pmm_free(page);
 
   debug_info("CPU - Status\n");
   for(unsigned int i = 0; i < num_cpu; i++)
diff --git a/kernel/include/cpu.h b/kernel/include/cpu.h
index ca17aa7..ad68aca 100644
--- a/kernel/include/cpu.h
+++ b/kernel/include/cpu.h
@@ -34,9 +34,10 @@ typedef struct cpu_t
   thread_t *current_thread;
   thread_t *last_thread;
   process_t *current_process;
-  uint64_t gdt[5];
+  uint64_t gdt[7];
   struct gdtp_st gdt_p;
   thread_t *scheduler;
+  tss_t tss;
 }__attribute__((packed)) cpu_t;
 
 extern cpu_t cpus[];
diff --git a/kernel/include/gdt.h b/kernel/include/gdt.h
index 8db6099..ab60c53 100644
--- a/kernel/include/gdt.h
+++ b/kernel/include/gdt.h
@@ -4,6 +4,7 @@
 #define SEG_KDATA 0x10
 #define SEG_UDATA 0x18
 #define SEG_UCODE 0x20
+#define   SEG_TSS        0x28
 
 #ifdef __ASSEMBLER__
 #define   GDT_WRITE      (1<<41)
@@ -20,6 +21,10 @@
 #define   GDT_RING3      (3LL<<45)
 #define   GDT_TSS        (9LL<<40)
 
+#define   TSS_BLO(base)  ((((base)&0xFFFF)<<16) | ((((base)>>16)&0xFF)<<32) | ((((base)>>24)&0xFF)<<56))
+#define   TSS_BHI(base)  (((base)>>32)&0xFFFFFFFF)
+#define   TSS_LIM(lim)   (((lim)&0xFFFF) | ((((lim)>>16)&0xF)<<48))
+
 #include <stdint.h>
 
 extern uint64_t BootGDT;
@@ -32,6 +37,27 @@ struct gdtp_st
   uint32_t pad2;
 }__attribute__((packed));
 
+typedef struct
+{
+  uint32_t r1;
+  uint64_t rsp0;
+  uint64_t rsp1;
+  uint64_t rsp2;
+  uint64_t r2;
+  uint64_t ist1;
+  uint64_t ist2;
+  uint64_t ist3;
+  uint64_t ist4;
+  uint64_t ist5;
+  uint64_t ist6;
+  uint64_t ist7;
+  uint64_t r3;
+  uint16_t r4;
+  uint16_t io_mba;
+}__attribute__((packed)) tss_t;
+
 void load_gdt(struct gdtp_st *);
 void gdt_init();
+
+void load_tr(uint32_t segment);
 #endif