From 42baf14321ab20e41f84f94815432eeb57be196b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20Lov=C3=A9n?= <thomasloven@gmail.com>
Date: Thu, 22 Feb 2018 12:38:25 +0100
Subject: [PATCH] A bit of cleanup

---
 src/kernel/cpu/cpu.c      |  8 ++++----
 src/kernel/cpu/gdt.c      | 29 ++++++++++++++---------------
 src/kernel/include/cpu.h  |  8 ++++++--
 src/kernel/proc/process.c |  2 +-
 4 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/src/kernel/cpu/cpu.c b/src/kernel/cpu/cpu.c
index da598c5..222d14c 100644
--- a/src/kernel/cpu/cpu.c
+++ b/src/kernel/cpu/cpu.c
@@ -1,12 +1,12 @@
 #include <cpu.h>
 #include <interrupts.h>
 
-uint64_t gdt[6];
-uint8_t tss[104];
-void gdt_init(uint64_t *, void *);
+uint64_t global_gdt[6];
+uint8_t global_tss[104];
+void gdt_init();
 
 void cpu_init()
 {
   interrupt_init();
-  gdt_init(gdt, tss);
+  gdt_init();
 }
diff --git a/src/kernel/cpu/gdt.c b/src/kernel/cpu/gdt.c
index 7962337..a1b49e6 100644
--- a/src/kernel/cpu/gdt.c
+++ b/src/kernel/cpu/gdt.c
@@ -2,11 +2,12 @@
 #include <cpu.h>
 #include <memory.h>
 
-#define GDT_CODE      (3<<11)
+#define GDT_CODE      (0x18<<8)
+#define GDT_DATA      (0x12<<8)
+#define GDT_TSS       (0x09<<8)
 #define GDT_DPL(lvl)  ((lvl)<<13)
 #define GDT_PRESENT   (1<<15)
 #define GDT_LONG      (1<<21)
-#define GDT_TSS       (9<<8)
 
 struct gdt
 {
@@ -44,31 +45,29 @@ struct gdt BootGDT[] = {
   {0, 0},
   {0, GDT_PRESENT | GDT_DPL(0) | GDT_CODE | GDT_LONG},
   {0, GDT_PRESENT | GDT_DPL(3) | GDT_CODE | GDT_LONG},
-  {0, GDT_PRESENT | GDT_DPL(3) | (1<<12) | (1<<9)},
+  {0, GDT_PRESENT | GDT_DPL(3) | GDT_DATA},
   {0, 0},
   {0, 0},
 };
 
 struct gdtp GDTp = {2*8-1, BootGDT};
 
-
-void gdt_init(uint64_t *_gdt, void *_tss)
+void gdt_init()
 {
-  struct gdt *gdt = (struct gdt *)_gdt;
+  struct gdt *gdt = GDT();
   memcpy(gdt, BootGDT, sizeof(BootGDT));
 
-  struct tss *tss = _tss;
+  struct tss *tss = TSS();
   tss->io_mba = sizeof(struct tss);
 
   uint32_t tss_limit = sizeof(struct tss);
-  uint64_t tss_base = (uint64_t)_tss;
+  uint64_t tss_base = (uint64_t)tss;
   gdt[4].flags = GDT_PRESENT | GDT_TSS;
-  gdt[4].flags |= (((tss_base >> 24) & 0xFF) << 24);
-  gdt[4].flags |= ((tss_base >> 16) & 0xFF);
-  gdt[4].flags |= (((tss_limit >> 16) & 0xF) << 16);
+  gdt[4].flags |= ((tss_base >> 24) & 0xFF) << 24;
+  gdt[4].flags |= (tss_base >> 16) & 0xFF;
+  gdt[4].flags |= ((tss_limit >> 16) & 0xF) << 16;
   gdt[4].addr = ((tss_base & 0xFFFF) << 16) | (tss_limit & 0xFFFF);
-  gdt[5].flags = 0;
-  gdt[5].addr = ((tss_base >> 32) & 0xFFFFFFFF);
+  gdt[5].addr = (tss_base >> 32) & 0xFFFFFFFF;
 
   GDTp.len = 6*8 - 1;
   GDTp.gdt = gdt;
@@ -76,8 +75,8 @@ void gdt_init(uint64_t *_gdt, void *_tss)
   load_gdt(&GDTp);
 }
 
-void set_tss_rsp0(void *_tss, void *rsp0)
+void interrupt_stack(void *rsp0)
 {
-  struct tss *tss = _tss;
+  struct tss *tss = TSS();
   tss->rsp0 = (uint64_t)rsp0;
 }
diff --git a/src/kernel/include/cpu.h b/src/kernel/include/cpu.h
index beba505..5ffb426 100644
--- a/src/kernel/include/cpu.h
+++ b/src/kernel/include/cpu.h
@@ -3,8 +3,12 @@
 
 void cpu_init();
 
-extern uint8_t tss[];
-void set_tss_rsp0(void *tss, void *rsp0);
+extern uint64_t global_gdt[];
+extern uint8_t global_tss[];
+#define GDT() ((void *)global_gdt)
+#define TSS() ((void *)global_tss)
+
+void interrupt_stack(void *rsp0);
 
 
 void load_idt(void *);
diff --git a/src/kernel/proc/process.c b/src/kernel/proc/process.c
index a52ea18..9dee224 100644
--- a/src/kernel/proc/process.c
+++ b/src/kernel/proc/process.c
@@ -62,7 +62,7 @@ void scheduler()
 
     _proc = new;
     write_cr3(new->P4);
-    set_tss_rsp0(tss, new + PAGE_SIZE);
+    interrupt_stack(new + PAGE_SIZE);
     switch_stack(&sched_proc->stack_ptr, &new->stack_ptr);
 
     ready(_proc);