fixed some typos, added comments and some code cleanup

arch/x86/kernel/entry32.asm

@@ -70,7 +70,7 @@ stublet:
 ; jump to the boot processors's C code
     extern main
     call main
-    jmp $
+    jmp $ ; infinitive loop
 
 global cpu_init
 cpu_init:
@@ -112,7 +112,7 @@ global read_ip
 read_ip:
     mov eax, [esp+4]
     pop DWORD [eax]             ; Get the return address
-    add esp, 4                  ; Dirty Hack! read_ip cleanup the stacl
+    add esp, 4                  ; Dirty Hack! read_ip cleanup the stack
     jmp [eax]                   ; Return. Can't use RET because return
                                 ; address popped off the stack.
 

arch/x86/kernel/entry64.asm

@@ -30,7 +30,7 @@ extern kernel_end
 extern apic_mp
 
 ; We use a special name to map this section at the begin of our kernel
-; =>  Multiboot needs its magic number at the begin of the kernel
+; =>  Multiboot needs its magic number at the beginning of the kernel
 SECTION .mboot
 global start
 start:
@@ -42,19 +42,19 @@ mboot:
     ; Multiboot macros to make a few lines more readable later
     MULTIBOOT_PAGE_ALIGN	equ 1<<0
     MULTIBOOT_MEMORY_INFO	equ 1<<1
-    ; MULTIBOOT_AOUT_KLUDGE     equ 1<<16
+    ; MULTIBOOT_AOUT_KLUDGE	equ 1<<16
     MULTIBOOT_HEADER_MAGIC	equ 0x1BADB002
     MULTIBOOT_HEADER_FLAGS	equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO ; | MULTIBOOT_AOUT_KLUDGE
-    MULTIBOOT_CHECKSUM	equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
+    MULTIBOOT_CHECKSUM		equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
     EXTERN code, bss, end
 
     ; This is the GRUB Multiboot header. A boot signature
     dd MULTIBOOT_HEADER_MAGIC
     dd MULTIBOOT_HEADER_FLAGS
     dd MULTIBOOT_CHECKSUM
-    
+
 ALIGN 4
-; we need already a valid GDT to switch in the 64bit modus
+; we need already a valid GDT to switch in the 64bit mode
 GDT64:                           ; Global Descriptor Table (64-bit).
     .Null: equ $ - GDT64         ; The null descriptor.
     dw 0                         ; Limit (low).
@@ -81,7 +81,7 @@ GDT64:                           ; Global Descriptor Table (64-bit).
     dw $ - GDT64 - 1             ; Limit.
     dq GDT64                     ; Base.
 
-    times 256 DD 0
+    times 256 DD 0               ; stack for booting
 startup_stack:
 
 SECTION .data
@@ -129,8 +129,8 @@ smp_entry:
 
 ; enable paging
     mov eax, cr0
-    or eax, 1 << 31 | 1 << 0 ; Set the PG-bit, which is the 31nd bit, and the PM-bit, which is the 0th bit.
+    or eax, 1 << 31 | 1 << 0 ; Set the PG-bit, which is the 31nd bit, and the PE-bit, which is the 0th bit.
-    mov cr0, eax
+    mov cr0, eax             ; According to the multiboot spec the PE-bit has to be set by bootloader already!
 
     mov edi, [esp+4]           ; set argumet for smp_start
     lgdt [GDT64.Pointer]       ; Load the 64-bit global descriptor table.
@@ -342,7 +342,7 @@ Lc:
 
 ; enable paging
     mov eax, cr0
-    or eax, 1 << 31 | 1 << 0 ; Set the PG-bit, which is the 31nd bit, and the PM-bit, which is the 0th bit.
+    or eax, 1 << 31 | 1 << 0 ; Set the PG-bit, which is the 31nd bit, and the PE-bit, which is the 0th bit.
     mov cr0, eax
 
     pop ebx                  ; restore pointer to multiboot structure

arch/x86/mm/page32.c

@@ -71,7 +71,7 @@ page_dir_t* get_boot_pgd(void)
 /*
  * TODO: We create a full copy of the current task. Copy-On-Access will be the better solution.
  *
- * No PGD locking is needed because onls create_pgd use this function and holds already the
+ * No PGD locking is needed because only create_pgd use this function and holds already the
  * PGD lock.
  */
 inline static size_t copy_page_table(task_t* task, uint32_t pgd_index, page_table_t* pgt, int* counter)
@@ -650,7 +650,7 @@ static void pagefault_handler(struct state *s)
 			memset((void*) viraddr, 0x00, PAGE_SIZE);
 			return;
 		}
-		
+
 		kprintf("Could not map 0x%x at 0x%x\n", phyaddr, viraddr);
 		put_page(phyaddr);
 	}

arch/x86/mm/page64.c

@@ -55,8 +55,8 @@
 extern const void kernel_start;
 extern const void kernel_end;
 
-// boot task's page directory and page directory lock
+// boot task's page directory and p:age directory lock
-extern page_dir_t boot_pgd;
+extern page_dir_t boot_pgd; // TODO: initialization done in entry64.asm
 static spinlock_t kslock = SPINLOCK_INIT;
 static int paging_enabled = 0;
 
@@ -67,7 +67,7 @@ page_dir_t* get_boot_pgd(void)
 
 int create_pgd(task_t* task, int copy)
 {
-	// Currently, we support only kernel tasks
+	// TODO: Currently, we support only kernel tasks
 	// => all tasks are able to use the same pgd
 
 	if (BUILTIN_EXPECT(!paging_enabled, 0))
@@ -130,7 +130,7 @@ size_t virt_to_phys(size_t viraddr)
 
 	spinlock_irqsave_lock(&task->pgd_lock);
 
-	// Currently, we allocate pages only in kernel space.
+	// TODO: Currently, we allocate pages only in kernel space.
 	// => physical address of the page table is identical of the virtual address
 	pgt = (page_table_t*) (task->pgd->entries[idx_pd4] & PAGE_MASK);
 	if (!pgt)