Bootloader: Locate the kernel's data segment and clear it.

This was a constant source of stupid bugs and I kept postponing it because
I wasn't in the mood to write assembly code. Until now! :^)

Kernel/BochsVGADevice.cpp

@@ -24,11 +24,6 @@ BochsVGADevice& BochsVGADevice::the()
     return *s_the;
 }
 
-void BochsVGADevice::initialize_statics()
-{
-    s_the = nullptr;
-}
-
 BochsVGADevice::BochsVGADevice()
 {
     s_the = this;

Kernel/BochsVGADevice.h

@@ -10,7 +10,6 @@ class BochsVGADevice {
     AK_MAKE_ETERNAL
 public:
     static BochsVGADevice& the();
-    static void initialize_statics();
 
     BochsVGADevice();
 

Kernel/Boot/boot.asm

@@ -25,9 +25,13 @@ boot:
     mov     ax, 0x2401
     int     0x15
 
-    mov     bx, 0x1000
+    ; HACK: Load the ELF kernel at 0xf000. Assuming that the first
+    ;       LOAD header has a file offset of 0x1000, this puts _start
+    ;       at 0x10000 which we jump to later.
+    ;       This is all quite rickety.
+    mov     bx, 0xf00
     mov     es, bx
-    xor     bx, bx              ; Load kernel @ 0x10000
+    xor     bx, bx
 
     mov cx, word [cur_lba]
 .sector_loop:
@@ -65,6 +69,53 @@ boot:
     xor al, al
     out dx, al
 
+    ; Let's look at the ELF header.
+    mov bx, 0xf00
+    mov fs, bx
+    cmp [fs:0], dword 0x464c457f ; ELF magic: { 0x7f "ELF" }
+    jne fug
+
+    cmp [fs:24], dword 0x10000 ; Entry should be 0x10000
+    jne fug
+
+    mov ebx, dword [fs:28] ; EBX <- program header table
+    mov ecx, dword [fs:44] ; ECX <- program header count
+
+; Let's find the BSS and clear it.
+
+parse_program_header:
+    cmp [fs:ebx], dword 0x1 ; Is Load segment?
+    jne .next
+
+    cmp [fs:ebx+24], dword 0x6 ; Is read+write but not execute?
+    jne .next
+
+    mov edi, [fs:ebx+8] ; EDI <- p_vaddr
+    add edi, [fs:ebx+16] ; skip over 'p_filesz' bytes (leave them intact)
+
+    push ecx
+
+    sub edi, [fs:ebx+16] ; skip over 'p_filesz' bytes (see above)
+
+    ; Since we're in 16-bit real mode, create a segment address.
+    mov eax, edi
+    shr eax, 4
+    mov es, ax
+    and edi, 0xf
+
+    mov ecx, [fs:ebx+20] ; ECX <- p_memsz
+    xor al, al
+    rep stosb
+
+    pop ecx
+
+.next:
+    add ebx, 32
+    loop parse_program_header
+
+; Okay we're all set to go!
+
+lets_go:
     lgdt [cs:test_gdt_ptr]
 
     mov eax, cr0
@@ -182,7 +233,7 @@ convert_lba_to_chs:
     ret 
     
 cur_lba:
-    dw 9
+    dw 1
 sectors_per_track:
     dw 18
 heads:

Kernel/FileSystem.cpp

@@ -23,13 +23,6 @@ HashTable<Inode*>& all_inodes()
     return *s_inode_set;
 }
 
-void FS::initialize_globals()
-{
-    s_lastFileSystemID = 0;
-    s_fs_map = nullptr;
-    s_inode_set = nullptr;
-}
-
 FS::FS()
     : m_fsid(++s_lastFileSystemID)
 {

Kernel/FileSystem.h

@@ -23,7 +23,6 @@ class VMObject;
 
 class FS : public Retainable<FS> {
 public:
-    static void initialize_globals();
     virtual ~FS();
 
     unsigned fsid() const { return m_fsid; }

Kernel/PTYMultiplexer.cpp

@@ -12,11 +12,6 @@ PTYMultiplexer& PTYMultiplexer::the()
     return *s_the;
 }
 
-void PTYMultiplexer::initialize_statics()
-{
-    s_the = nullptr;
-}
-
 PTYMultiplexer::PTYMultiplexer()
     : CharacterDevice(5, 2)
 {

Kernel/PTYMultiplexer.h

@@ -13,7 +13,6 @@ public:
     virtual ~PTYMultiplexer() override;
 
     static PTYMultiplexer& the();
-    static void initialize_statics();
 
     // ^CharacterDevice
     virtual RetainPtr<FileDescriptor> open(int& error, int options) override;

Kernel/ProcessGUI.cpp

@@ -12,11 +12,6 @@
 
 void Process::initialize_gui_statics()
 {
-    Font::initialize();
-    WSMessageLoop::initialize();
-    WSWindowManager::initialize();
-    WSScreen::initialize();
-
     new WSMessageLoop;
 }
 

Kernel/VirtualFileSystem.cpp

@@ -19,12 +19,6 @@ VFS& VFS::the()
     return *s_the;
 }
 
-void VFS::initialize_globals()
-{
-    s_the = nullptr;
-    FS::initialize_globals();
-}
-
 VFS::VFS()
 {
 #ifdef VFS_DEBUG

Kernel/VirtualFileSystem.h

@@ -39,8 +39,6 @@ class VFS;
 class VFS {
     AK_MAKE_ETERNAL
 public:
-    static void initialize_globals();
-
     class Mount {
     public:
         Mount(InodeIdentifier host, RetainPtr<FS>&&);

Kernel/init.cpp

@@ -151,8 +151,6 @@ void init()
     gdt_init();
     idt_init();
 
-    PTYMultiplexer::initialize_statics();
-    VFS::initialize_globals();
     vfs = new VFS;
 
     keyboard = new Keyboard;
@@ -169,10 +167,6 @@ void init()
     kprintf("Starting Serenity Operating System...\n");
 
     MemoryManager::initialize();
-
-    StringImpl::initialize_globals();
-    BochsVGADevice::initialize_statics();
-
     PIT::initialize();
 
     memset(&system, 0, sizeof(system));