Sync x86_64 trampoline with bootloader

src/asm/x86_64/trampoline.asm

@@ -26,24 +26,22 @@ startup_ap:
     ; initialize stack to invalid value
     mov sp, 0
 
-    ;cr3 holds pointer to PML4
+    ; cr3 holds pointer to PML4
     mov edi, [trampoline.page_table]
     mov cr3, edi
 
-    ; Enable FPU
+    ; enable FPU
     mov eax, cr0
     and al, 11110011b ; Clear task switched (3) and emulation (2)
     or al, 00100010b ; Set numeric error (5) monitor co-processor (1)
     mov cr0, eax
 
-    ; 18: Enable OSXSAVE
-    ; 10: Unmasked SSE exceptions
     ; 9: FXSAVE/FXRSTOR
     ; 7: Page Global
     ; 5: Page Address Extension
     ; 4: Page Size Extension
     mov eax, cr4
-    or eax, 1 << 18 | 1 << 10 | 1 << 9 | 1 << 7 | 1 << 5 | 1 << 4
+    or eax, 1 << 9 | 1 << 7 | 1 << 5 | 1 << 4
     mov cr4, eax
 
     ; initialize floating point registers
@@ -52,12 +50,13 @@ startup_ap:
     ; load protected mode GDT
     lgdt [gdtr]
 
+    ; enable long mode
     mov ecx, 0xC0000080               ; Read from the EFER MSR.
     rdmsr
     or eax, 1 << 11 | 1 << 8          ; Set the Long-Mode-Enable and NXE bit.
     wrmsr
 
-    ;enabling paging and protection simultaneously
+    ; enabling paging and protection simultaneously
     mov ebx, cr0
     ; 31: Paging
     ; 16: write protect kernel