From b96b09a8b562434f9f74dc5879c22a6d9cddc4fd Mon Sep 17 00:00:00 2001
From: Alex <enderice2@users.noreply.github.com>
Date: Thu, 13 Oct 2022 06:43:12 +0300
Subject: [PATCH] kernel boots with multiboot2

---
 Architecture/aarch64/boot.S    |  2 +-
 Architecture/aarch64/linker.ld |  4 +-
 Architecture/amd64/linker.ld   |  6 +++
 Architecture/i686/boot.asm     | 72 ++++++++++++++++++++++++++++++++++
 Architecture/i686/linker.ld    | 45 +++++++++++++--------
 5 files changed, 109 insertions(+), 20 deletions(-)
 create mode 100644 Architecture/i686/boot.asm

diff --git a/Architecture/aarch64/boot.S b/Architecture/aarch64/boot.S
index 5d524b2..cf7502c 100644
--- a/Architecture/aarch64/boot.S
+++ b/Architecture/aarch64/boot.S
@@ -11,7 +11,7 @@ _start:
     str     xzr, [x5], #8
     sub     w6, w6, #1
     cbnz    w6, 1b
-2:  bl      aarch64Entry
+2:  bl      arm64Entry
 Halt:
     wfe
     b Halt
diff --git a/Architecture/aarch64/linker.ld b/Architecture/aarch64/linker.ld
index c6567c6..12f5c58 100644
--- a/Architecture/aarch64/linker.ld
+++ b/Architecture/aarch64/linker.ld
@@ -36,7 +36,7 @@ SECTIONS
 
     /DISCARD/ :
     {
-        *(.eh_frame)
-        *(.note .note.*)
+        *(.comment*)
+        *(.note*)
     }
 }
diff --git a/Architecture/amd64/linker.ld b/Architecture/amd64/linker.ld
index 07992d3..81d377d 100644
--- a/Architecture/amd64/linker.ld
+++ b/Architecture/amd64/linker.ld
@@ -36,4 +36,10 @@ SECTIONS
     }
     . += CONSTANT(MAXPAGESIZE);
     _kernel_end = ALIGN(CONSTANT(MAXPAGESIZE));
+
+    /DISCARD/ :
+    {
+        *(.comment*)
+        *(.note*)
+    }
 }
diff --git a/Architecture/i686/boot.asm b/Architecture/i686/boot.asm
new file mode 100644
index 0000000..d371c46
--- /dev/null
+++ b/Architecture/i686/boot.asm
@@ -0,0 +1,72 @@
+KERNEL_VIRTUAL_BASE EQU 0xE0000000
+
+section .multiboot2.data
+align 8
+HEADER_START:
+        dd 0xE85250D6
+        dd 0
+        dd (HEADER_END - HEADER_START)
+        dd -(0xE85250D6 + (HEADER_END - HEADER_START))
+
+align 8
+        dw 0
+        dw 0
+        dd 8
+
+HEADER_END:
+
+section .bss
+STACK_BOTTOM: resb 16384
+STACK_TOP:
+
+align 4096
+BOOT_PAGE_DIR0: resb 4096
+BOOT_PAGE_TBL0: resb 4096
+BOOT_PAGE_TBL1: resb 4096
+
+section .multiboot2.text
+extern x32Entry
+extern _kernel_start
+extern _kernel_end
+global _start
+
+_start:
+        mov esp, STACK_TOP - KERNEL_VIRTUAL_BASE
+        mov edi, BOOT_PAGE_TBL0 - KERNEL_VIRTUAL_BASE
+        mov esi, 0
+        mov ecx, 2048 - 301
+.PagingLoop:
+        cmp esi, _kernel_start - KERNEL_VIRTUAL_BASE
+        jl .LoopInside
+        cmp esi, _kernel_end - KERNEL_VIRTUAL_BASE
+        jge .LoopEnd
+        mov eax, esi
+        or eax, 3
+        mov [edi], eax
+.LoopInside:
+        add esi, 4096
+        add edi, 4
+        loop .PagingLoop
+.LoopEnd:
+        push ebx
+        mov dword [BOOT_PAGE_DIR0 - KERNEL_VIRTUAL_BASE + (000 * 4)], (BOOT_PAGE_TBL0 - KERNEL_VIRTUAL_BASE + 3)
+        mov dword [BOOT_PAGE_DIR0 - KERNEL_VIRTUAL_BASE + (001 * 4)], (BOOT_PAGE_TBL1 - KERNEL_VIRTUAL_BASE + 3)
+        mov dword [BOOT_PAGE_DIR0 - KERNEL_VIRTUAL_BASE + (896 * 4)], (BOOT_PAGE_TBL0 - KERNEL_VIRTUAL_BASE + 3)
+        mov dword [BOOT_PAGE_DIR0 - KERNEL_VIRTUAL_BASE + (897 * 4)], (BOOT_PAGE_TBL1 - KERNEL_VIRTUAL_BASE + 3)
+        mov ecx, BOOT_PAGE_DIR0 - KERNEL_VIRTUAL_BASE
+        mov cr3, ecx
+        mov ecx, cr0
+        or ecx, 0x80010000
+        mov cr0, ecx
+        add esp, KERNEL_VIRTUAL_BASE
+        mov eax, CallKernelMain
+        jmp eax
+
+section .text
+CallKernelMain:
+        push ebx
+        call x32Entry
+        cli
+.hang:
+        hlt
+        jmp .hang
diff --git a/Architecture/i686/linker.ld b/Architecture/i686/linker.ld
index aad40cb..0a76813 100644
--- a/Architecture/i686/linker.ld
+++ b/Architecture/i686/linker.ld
@@ -1,45 +1,56 @@
 OUTPUT_FORMAT(elf32-i386)
 OUTPUT_ARCH(i386)
 
-ENTRY(Entry)
+ENTRY(_start)
+
+KERNEL_VIRTUAL_BASE = 0xE0000000;
 
 SECTIONS
 {
-    . += 0xC0000000;
-    _kernel_start = .;
+    . = 0x00100000;
+    _kernel_start = . + KERNEL_VIRTUAL_BASE;
 
-    .text :
+    .multiboot.data :
+    {
+        *(.multiboot2.data)
+    }
+
+    .multiboot.text :
+    {
+        *(.multiboot2.text)
+    }
+
+    . += KERNEL_VIRTUAL_BASE;
+    .text ALIGN(4096) : AT(ADDR(.text) - KERNEL_VIRTUAL_BASE)
     {
         *(.text .text.*)
     }
-    _kernel_text_end = ALIGN(CONSTANT(MAXPAGESIZE));
-    . += CONSTANT(MAXPAGESIZE);
+    _kernel_text_end = .;
 
-    .data :
+    .data ALIGN (4096) : AT(ADDR(.data) - KERNEL_VIRTUAL_BASE)
     {
         *(.data .data.*)
     }
-    _kernel_data_end = ALIGN(CONSTANT(MAXPAGESIZE));
-    . += CONSTANT(MAXPAGESIZE);
+    _kernel_data_end = .;
 
-    .rodata :
+    .rodata ALIGN (4096) : AT(ADDR(.rodata) - KERNEL_VIRTUAL_BASE)
     {
         *(.rodata .rodata.*)
     }
-    _kernel_rodata_end = ALIGN(CONSTANT(MAXPAGESIZE));
-    . += CONSTANT(MAXPAGESIZE);
+    _kernel_rodata_end = .;
 
-    .bss :
+    .bss ALIGN (4096) : AT(ADDR(.bss) - KERNEL_VIRTUAL_BASE)
     {
+        _sbss = .;
         *(COMMON)
         *(.bss .bss.*)
+        _ebss = .;
     }
-    . += CONSTANT(MAXPAGESIZE);
-    _kernel_end = ALIGN(CONSTANT(MAXPAGESIZE));
+    _kernel_end = .;
 
     /DISCARD/ :
     {
-        *(.eh_frame)
-        *(.note .note.*)
+        *(.comment*)
+        *(.note*)
     }
 }