Move the kernel to high memory

src/kernel/Link.ld

@@ -1,15 +1,27 @@
 ENTRY(_start)
 
+KERNEL_OFFSET = 0xFFFFFF8000000000;
+KERNEL_START = 0x10000;
+
 SECTIONS
 {
-  .text :
+  . = KERNEL_START + KERNEL_OFFSET;
+  .text : AT(ADDR(.text) - KERNEL_OFFSET)
   {
     *(.multiboot)
     *(.text)
   }
-
-  .bss :
+  .rodata : AT(ADDR(.rodata) - KERNEL_OFFSET)
   {
+    *(.rodata*)
+  }
+  .data : AT(ADDR(.data) - KERNEL_OFFSET)
+  {
+    *(.data)
+  }
+  .bss : AT(ADDR(.bss) - KERNEL_OFFSET)
+  {
+    *(.COMMON)
     *(.bss)
   }
 }

src/kernel/boot/boot.S

@@ -14,7 +14,7 @@ _start:
   cli
 
   //; Set up a known stack
-  mov esp, offset BootStack
+  mov esp, offset V2P(BootStack)
 
   //; Set CR4.PAE
   //; enabling Page Address Extension
@@ -23,7 +23,7 @@ _start:
   mov cr4, eax
 
   //; Load a P4 page table
-  mov eax, offset BootP4
+  mov eax, offset V2P(BootP4)
   mov cr3, eax
 
   //; Set EFER.LME
@@ -40,10 +40,10 @@ _start:
   mov cr0, eax
 
   //; Load a new GDT
-  lgdt [BootGDTp]
+  lgdt [V2P(BootGDTp)]
 
   //; and update the code selector by a long jump
-  jmp 0x8:long_mode_start
+  jmp 0x8:V2P(long_mode_start)
 
 .code64
   long_mode_start:
@@ -54,5 +54,10 @@ _start:
   mov ds, eax
   mov es, eax
 
+  movabs rax, offset upper_memory
+  jmp rax
+
+  upper_memory:
+
   //; Loop infinitely
   jmp $

src/kernel/boot/boot_PT.S

@@ -5,17 +5,18 @@
 .align PAGE_SIZE
 .global BootP4
 BootP4:
-  .quad offset BootP3 + (PAGE_PRESENT | PAGE_WRITE)
-  .rept ENTRIES_PER_PT - 1
+  .quad offset V2P(BootP3) + (PAGE_PRESENT | PAGE_WRITE)
+  .rept ENTRIES_PER_PT - 2
     .quad 0
   .endr
+  .quad offset V2P(BootP3) + (PAGE_PRESENT | PAGE_WRITE)
 BootP3:
-  .quad offset BootP2 + (PAGE_PRESENT | PAGE_WRITE)
+  .quad offset V2P(BootP2) + (PAGE_PRESENT | PAGE_WRITE)
   .rept ENTRIES_PER_PT - 1
     .quad 0
   .endr
 BootP2:
-  .quad offset BootP1 + (PAGE_PRESENT | PAGE_WRITE)
+  .quad offset V2P(BootP1) + (PAGE_PRESENT | PAGE_WRITE)
   .rept ENTRIES_PER_PT - 1
     .quad 0
   .endr

src/kernel/include/memory.h

@@ -1,4 +1,6 @@
 #pragma once
+#define KERNEL_OFFSET 0xFFFFFF8000000000
+#define V2P(a) ((a) - KERNEL_OFFSET)
 
 #define PAGE_PRESENT      0x001
 #define PAGE_WRITE        0x002