Kernel: Multiboot data and kernel command lines are now global variables

kernel/arch/i386/VESA.cpp

@@ -90,13 +90,13 @@ namespace VESA
 
 	bool Initialize()
 	{
-		if (!(s_multiboot_info->flags & MULTIBOOT_FLAGS_FRAMEBUFFER))
+		if (!(g_multiboot_info->flags & MULTIBOOT_FLAGS_FRAMEBUFFER))
 		{
 			derrorln("bootloader did not provide a memory map");
 			return false;
 		}
 
-		auto& framebuffer = s_multiboot_info->framebuffer;
+		auto& framebuffer = g_multiboot_info->framebuffer;
 		s_addr		= framebuffer.addr;
 		s_bpp		= framebuffer.bpp;
 		s_pitch		= framebuffer.pitch;

kernel/arch/i386/boot.S

@@ -7,7 +7,7 @@
 .set MB_CHECKSUM,	-(MB_MAGIC + MB_FLAGS)		#checksum of above, to prove we are multiboot
 
 # Multiboot header
-.section .multiboot
+.section .multiboot, "aw"
 	.align 4
 	.long MB_MAGIC
 	.long MB_FLAGS
@@ -19,28 +19,111 @@
 	.long 600
 	.long 32
 
- # Create stack
-.section .bss
+.section .bss, "aw", @nobits
+ 	# Create stack
 	stack_bottom:
-	.skip 16384		# 16 KiB
+		.skip 16384
 	stack_top:
+	
+	.global g_kernel_cmdline
+	g_kernel_cmdline:
+		.skip 4096
+
+	# Reserve memory for paging structures,
+	# we will identity map first 4 MiB
+
+	# 0 MiB -> 2 MiB: kernel
+	# 2 MiB -> 3 MiB: kmalloc
+	# 3 MiB -> 4 Mib: kmalloc_eternal
+	.align 32
+	boot_page_directory_pointer_table:
+		.skip 4 * 8
+	.align 4096
+	boot_page_directory1:
+		.skip 512 * 8
+
+	
+
+.section .text, "a"
+
+.global g_multiboot_info
+g_multiboot_info:
+	.skip 4
+.global g_multiboot_magic
+g_multiboot_magic:
+	.skip 4
+
+has_cpuid:
+	pushfl
+	pushfl
+	xorl $0x00200000, (%esp)
+	popfl
+	pushfl
+	popl %eax
+	xorl (%esp), %eax
+	popfl
+	andl $0x00200000, %eax
+	ret
+
+has_pae:
+	call has_cpuid
+	cmpl $0, %eax
+	jz .exit
+	movl $0, %eax
+	cpuid
+	movl %edx, %eax
+	andl $0x40, %eax # PAE is bit 6 in edx
+.exit:
+	ret
 
-.section .text
 .global _start
 .type _start, @function
 _start:
+	# Initialize stack and multiboot info
 	movl $stack_top, %esp
+	movl %eax, g_multiboot_magic
+	movl %ebx, g_multiboot_info
 
-	pushl %eax
-	pushl %ebx
 
+	# Copy kernel command line to known location
+	movl %ebx, %esi
+	addl $16, %esi
+	movl (%esi), %esi
+	movl $1024, %ecx
+	movl $g_kernel_cmdline, %edi
+	rep movsl
+
+	call has_pae
+	cmpl $0, %eax
+	jz system_halt
+
+	# identity map first 4 MiB
+	movl $(0x00000000           + 0x83), boot_page_directory1 + 0
+	movl $(0x00200000           + 0x83), boot_page_directory1 + 8
+	movl $(boot_page_directory1 + 0x01), boot_page_directory_pointer_table
+
+	# enable PAE
+	movl %cr4, %ecx
+	orl $0x20, %ecx
+	movl %ecx, %cr4
+
+	# set address of paging structures
+	movl $boot_page_directory_pointer_table, %ecx
+	movl %ecx, %cr3
+
+	# enable paging
+	movl %cr0, %ecx
+	orl $0x80000000, %ecx
+	movl %ecx, %cr0
+
+	xchgw %bx, %bx
+	# call global constuctors
 	call _init
 
+	# call to the kernel itself
 	call kernel_main
 
+system_halt:
 	cli
-1:
-	hlt
+1:	hlt
 	jmp 1b
-
-.size _start, . - _start

kernel/arch/i386/linker.ld

@@ -1,9 +1,9 @@
-ENTRY(_start)
- 
+ENTRY (_start)
+
 SECTIONS
 {
-	. = 1M;
- 
+	. = 0x00100000;
+
 	.text BLOCK(4K) : ALIGN(4K)
 	{
 		*(.multiboot)
@@ -22,4 +22,6 @@ SECTIONS
 		*(COMMON)
 		*(.bss)
 	}
-}
+
+	g_kernel_end = .;
+}

kernel/arch/i386/make.config

@@ -9,5 +9,6 @@ $(ARCHDIR)/boot.o		\
 $(ARCHDIR)/CPUID.o		\
 $(ARCHDIR)/GDT.o		\
 $(ARCHDIR)/IDT.o		\
+$(ARCHDIR)/MMU.o		\
 $(ARCHDIR)/Paging.o		\
 $(ARCHDIR)/VESA.o		\