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Revert "Revert "LONG MODE MULTIBOOT WORKS gsp!"" 

This reverts commit b910f6961a657798726df37831e78824879f3c2c.
This commit is contained in:
Adrien Bourmault 2019-03-06 20:05:18 +01:00
parent 810371a1df
commit 9f2ebed70a
3 changed files with 57 additions and 32 deletions
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61
boot/loader/loader.asm
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@ -38,7 +38,7 @@ _start:
mov es, ax ; And es because it is jealous
;mov [Bootdrv], dl
xor dl, dl
jmp 0x0000:main ; pas sûr
jmp 0x0000:_loader ; pas sûr
;; Magnificent multiboot header for GRUB ------------------------------------ ;;
MB_header:
@ -60,7 +60,7 @@ MB_start:
push eax ; 2nd argument is magic number
push ebx ; 1st argument multiboot info pointer
mov ecx, eax
call main
call _loader
add esp, 8 ; Cleanup arguments "A la MIPS"
jmp Die ; Aufwiedersehen
@ -79,42 +79,39 @@ Die:
jmp $
;; THE CODE ----------------------------------------------------------------- ;;
main:
call MB_check
; ---------------------------------------------------------------------------- ;
; _loader ;
; ;
; This is the function that initiates the launch of OS/K. It verifies that ;
; Grub has properly loaded this loader and makes the appropriate setup so ;
; that the kernel will work properly ;
; ;
; Why this original design ? Because it works well and prevent us to cause ;
; triple faults by aligment error or too long jumps (yup, it can be a problem);
; ;
; ---------------------------------------------------------------------------- ;
_loader:
jmp lbegin
%include "boot/loader/multiboot/check.inc"
lbegin:
call MB_check
jmp lnext
%include "boot/loader/cpu/cpuid.inc"
lnext:
call Check_cpuid
call Is64Bits
jmp lnext2
%include "boot/loader/mem/structures.inc"
lnext2:
call Setup_paging
jmp lnext3
%include "boot/loader/mem/management.inc"
;; Registering paging
mov eax, PML4_table
mov cr3, eax ; Load PML4 to cr3
mov eax, cr4
or eax, 1 << 5
mov cr4, eax ; Enable PAE
;; Activate long mode
mov ecx, 0xC0000080 ; address of MSR
rdmsr ; read MSR
or eax, 1 << 8 ; LME = 1. (Long Mode Enable)
wrmsr ; write MSR
;; Enable paging
mov eax, cr0
or eax, 1 << 31 ; make MSR bit 31 (PG = Paging) to 1 :
; |1|000000000000000000000000000000
; |
; `------ Paging bit
mov cr0, eax
lnext3:
mov dword [0xb8000], 0x2f4b2f4f
ret
;; INCLUDES ----------------------------------------------------------------- ;;
%include "boot/loader/cpu/cpuid.inc"
%include "boot/loader/multiboot/check.inc"
%include "boot/loader/mem/structures.inc"
%include "boot/loader/mem/management.inc"

28
boot/loader/mem/management.inc
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@ -52,3 +52,31 @@ Setup_paging:
jne .map_p2_table ; else map the next entry
ret
; ---------------------------------------------------------------------------- ;
; Enable long mode and paging ;
; ---------------------------------------------------------------------------- ;
Go64:
;; Registering paging
mov eax, PML4_table
mov cr3, eax ; Load PML4 to cr3
mov eax, cr4
or eax, 1 << 5
mov cr4, eax ; Enable PAE
;; Activate long mode
mov ecx, 0xC0000080 ; address of MSR
rdmsr ; read MSR
or eax, 1 << 8 ; LME = 1. (Long Mode Enable)
wrmsr ; write MSR
;; Enable paging
mov eax, cr0
or eax, 1 << 31 ; make MSR bit 31 (PG = Paging) to 1 :
; |1|000000000000000000000000000000
; |
; `------ Paging bit
mov cr0, eax
ret

BIN
build/obj/boot/loader.bin
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