Stub support mb2 for i386

Architecture/i386/Bootstrap/Multiboot/2/Start.s_fixme

@@ -0,0 +1,117 @@
+/*
+   This file is part of Fennix Kernel.
+
+   Fennix Kernel is free software: you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation, either version 3 of
+   the License, or (at your option) any later version.
+
+   Fennix Kernel is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+.intel_syntax noprefix
+
+.code32
+.equ KERNEL_STACK_SIZE, 0x4000 /* 16KB */
+
+.extern DetectCPUID
+.extern Detect64Bit
+.extern DetectPSE
+.extern DetectPAE
+.extern multiboot_main
+.extern LoadGDT32
+.extern BootPageTable
+.extern UpdatePageTable
+.extern GDT64.Ptr
+.extern GDT64.Code
+.extern GDT64.Data
+
+.section .bootstrap.data
+MB_HeaderMagic:
+	.quad 0
+
+MB_HeaderInfo:
+	.quad 0
+
+.section .bootstrap.text
+
+.global Multiboot2_start
+Multiboot2_start:
+	cli
+
+	mov [MB_HeaderMagic], eax
+	mov [MB_HeaderInfo], ebx
+
+	call DetectCPUID
+	cmp eax, 0
+	je $
+
+	call Detect64Bit
+	cmp eax, 0
+	je $
+
+	call DetectPSE
+	cmp eax, 0
+	je $
+
+	call DetectPAE
+	cmp eax, 0
+	je $
+
+	mov ecx, cr4
+	or ecx, 0x00000010 /* Set PSE in CR4 */
+	or ecx, 0x00000020 /* Set PAE in CR4 */
+	mov cr4, ecx
+
+	call LoadGDT32
+	call UpdatePageTable
+
+	mov ecx, BootPageTable
+	mov cr3, ecx
+
+	mov ecx, 0xC0000080 /* EFER */
+	rdmsr
+	or eax, 0x800 | 0x100 | 0x1 /* Set LME, LMA, SCE */
+	wrmsr
+
+	mov ecx, cr0
+	or ecx, 0x80000001 /* Set PG and PE in CR0 */
+	mov cr0, ecx
+
+	lgdt [GDT64.Ptr]
+	jmp GDT64.Code:HigherHalfStart
+
+.extern UpdatePageTable64
+
+.code64
+HigherHalfStart:
+	mov ax, GDT64.Data
+	mov ds, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+	mov ss, ax
+
+	call UpdatePageTable64
+
+	mov rsp, KernelStack + KERNEL_STACK_SIZE
+	mov rbp, 0
+	mov rdi, [MB_HeaderMagic]
+	mov rsi, [MB_HeaderInfo]
+	push rsi
+	push rdi
+	call multiboot_main
+.Hang:
+	hlt
+	jmp .Hang
+
+.section .bootstrap.bss
+.align 16
+KernelStack:
+	.space KERNEL_STACK_SIZE