feat: start of paging setup

boot/boot.S

@@ -19,7 +19,7 @@ forced to be within the first 8 KiB of the kernel file.
 .long CHECKSUM
 
 #.include "gdt.S"
-.section .data
+.section .data.boot
 gdt:
 .quad 0x0000000000000000
 .quad 0x00CF9A000000FFFF
@@ -42,7 +42,7 @@ System V ABI standard and de-facto extensions. The compiler will assume the
 stack is properly aligned and failure to align the stack will result in
 undefined behavior.
 */
-.section .bss
+.section .bss.boot
 .align 16
 stack_bottom:
 .skip 16384 # 16 KiB
@@ -53,7 +53,7 @@ The linker script specifies _start as the entry point to the kernel and the
 bootloader will jump to this position once the kernel has been loaded. It
 doesn't make sense to return from this function as the bootloader is gone.
 */
-.section .text
+.section .text.boot
 .global _start
 .type _start, @function
 _start:
@@ -103,6 +103,25 @@ _start:
 
 continue_boot:
     sti
+
+    // setting up paging
+    // id map first 4MB using PSE. With 
+    movl $135, kernel_page_directory - 0xC0000000
+    movl $135, kernel_page_directory - 0xC0000000 + 3072
+    //  load into cr3
+    movl $kernel_page_directory - 0xC0000000, %eax
+    movl %eax, %cr3
+    // enable PSE TODO validate if PSE is actually supported
+    movl %cr4, %eax
+    orl $0x10, %eax
+    movl %eax, %cr4
+    // enable paging
+    movl %cr0, %eax
+    orl $0x80000000, %eax
+    movl %eax, %cr0
+    nop
+    pushl 0
+    popl %eax
 	/*
 	Enter the high-level kernel. The ABI requires the stack is 16-byte
 	aligned at the time of the call instruction (which afterwards pushes