From 1e275732c5d2fa08326086a33b5df17829a90062 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <lankes@lfbs.rwth-aachen.de>
Date: Sun, 10 Jun 2012 23:40:22 +0200
Subject: [PATCH] simplify the APIC and GDT code

---
 arch/x86/include/asm/tasks.h |  3 +--
 arch/x86/kernel/apic.c       | 13 ++++++-------
 arch/x86/kernel/gdt.c        | 10 ++--------
 arch/x86/mm/page32.c         |  4 ++--
 arch/x86/mm/page64.c         |  4 ++--
 5 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/tasks.h b/arch/x86/include/asm/tasks.h
index 6761b240..fc138802 100644
--- a/arch/x86/include/asm/tasks.h
+++ b/arch/x86/include/asm/tasks.h
@@ -75,12 +75,11 @@ int create_default_frame(task_t* task, entry_point_t ep, void* arg);
 
 /** @brief Register a task's TSS at GDT
  *
- * @param task Pointer to task structure
  * @return
  * - 0 on success
  * - -EINVAL (-22) on failure
  */
-int register_task(task_t* task);
+int register_task(void);
 
 /** @brief Jump back to user code
  *
diff --git a/arch/x86/kernel/apic.c b/arch/x86/kernel/apic.c
index 3d76c425..e0abceb3 100644
--- a/arch/x86/kernel/apic.c
+++ b/arch/x86/kernel/apic.c
@@ -289,7 +289,7 @@ extern int smp_main(void);
 
 void smp_start(uint32_t id)
 {
-	uint32_t i;
+	size_t i;
 
 	atomic_int32_inc(&cpu_online);
 
@@ -309,7 +309,7 @@ void smp_start(uint32_t id)
 	idt_install();
 
 	/* enable paging */
-	write_cr3((uint32_t)get_boot_pgd());
+	write_cr3((size_t)get_boot_pgd());
 	i = read_cr0();
 	i = i | (1 << 31);
 	write_cr0(i);
@@ -320,9 +320,9 @@ void smp_start(uint32_t id)
 
 	/*
 	 * we turned on paging
-	 * => now, we are able to register our task for Task State Switching
+	 * => now, we are able to register our task
 	 */
-	register_task(per_core(current_task));
+	register_task();
 
 	// enable additional cpu features
 	cpu_detection();
@@ -577,16 +577,14 @@ static int apic_probe(void)
 	uint32_t i, count;
 	int isa_bus = -1;
 
-#if 1
 #ifdef CONFIG_X86_32
+#if 1
 	apic_mp = search_apic(0xF0000, 0x100000);
 	if (apic_mp)
 		goto found_mp;
 	apic_mp = search_apic(0x9F000, 0xA0000);
 	if (apic_mp)
 		goto found_mp;
-#elif defined(CONFIG_X86_64)
-#endif
 #else
 	// searching MP signature in the reserved memory areas
 	if (mb_info && (mb_info->flags & MULTIBOOT_INFO_MEM_MAP)) {
@@ -619,6 +617,7 @@ static int apic_probe(void)
 		}
 	}
 #endif
+#endif
 found_mp:
 	if (!apic_mp) 
 		goto no_mp;
diff --git a/arch/x86/kernel/gdt.c b/arch/x86/kernel/gdt.c
index ebd73536..9dce69ac 100644
--- a/arch/x86/kernel/gdt.c
+++ b/arch/x86/kernel/gdt.c
@@ -39,12 +39,6 @@ static gdt_entry_t			gdt[GDT_ENTRIES] = {[0 ... GDT_ENTRIES-1] = {0, 0, 0, 0, 0,
  */
 extern void gdt_flush(void);
 
-/* 
- * This is defined in entry.asm. We use this for a
- * hardware-based task switch.
- */
-extern void tss_switch(uint32_t id);
-
 size_t* get_current_stack(void)
 {
 	task_t* curr_task = per_core(current_task);
@@ -61,12 +55,12 @@ size_t get_stack(uint32_t id)
 	return (size_t) kstacks[id] + KERNEL_STACK_SIZE - sizeof(size_t);
 }
 
-int register_task(task_t* task) 
+int register_task(void) 
 {
 	uint16_t sel;
 
 	sel = (CORE_ID+5) << 3;
-	asm volatile ("mov %0, %%ax; ltr %%ax" : : "ir"(sel) : "%eax");
+	asm volatile ("ltr %%ax" : : "a"(sel));
 
 	return 0;
 }
diff --git a/arch/x86/mm/page32.c b/arch/x86/mm/page32.c
index e29ec26b..a63a53fc 100644
--- a/arch/x86/mm/page32.c
+++ b/arch/x86/mm/page32.c
@@ -820,9 +820,9 @@ int arch_paging_init(void)
 
 	/*
 	 * we turned on paging
-	 * => now, we are able to register our task for Task State Switching
+	 * => now, we are able to register our task
 	 */
-	register_task(per_core(current_task));
+	register_task();
 
 	// APIC registers into the kernel address space
 	map_apic();
diff --git a/arch/x86/mm/page64.c b/arch/x86/mm/page64.c
index f9f81331..06aaeb23 100644
--- a/arch/x86/mm/page64.c
+++ b/arch/x86/mm/page64.c
@@ -635,9 +635,9 @@ int arch_paging_init(void)
 
 	/*
 	 * we turned on paging
-	 * => now, we are able to register our task for Task State Switching
+	 * => now, we are able to register our task
 	 */
-	register_task(per_core(current_task));
+	register_task();
 
 	// APIC registers into the kernel address space
 	map_apic();