(WIP) Loader for 64 bit kernel.

.gitignore

@@ -1,8 +1,9 @@
 # Project Folder (at least for now)
 .idea
 
-# Compiled Binaries
+# Compiled Binaries and ISOs
 *.bin
+*.iso
 
 # Compile Commands
 compile_commands.json

SConstruct

@@ -14,6 +14,7 @@ AddOption(
 target  = GetOption('target')
 
 env = Environment(tools =  ['default', 'compilation_db'])
+env.Append(CFLAGS = ['-ffreestanding'])
 env.Append(CXXFLAGS = ['-ffreestanding', '-fno-exceptions', '-fno-rtti', '-std=c++20'])
 env.Append(LINKFLAGS = ['-T', 'linker.ld', '-ffreestanding', '-nostdlib'])
 env.Append(CPPPATH = ['#targets/_any/include', '#bastl/include'])
@@ -21,6 +22,7 @@ env.Append(CCFLAGS = ['-g', '-O0'])
 
 env['KERNEL_SOURCES'] = []
 env['KERNEL_DEPENDENCIES'] = []
+env['ISO_FILES'] = []
 env = SConscript('bastl/SConscript', exports = 'env')
 env = SConscript('targets/_any/SConscript', exports = 'env')
 env = SConscript(f'targets/{target}/SConscript', exports = 'env')
@@ -28,9 +30,15 @@ env = SConscript(f'targets/{target}/SConscript', exports = 'env')
 prog_os = env.Program(
     target = 'os.bin',
     source = env['KERNEL_SOURCES'],
-    LIBS = ['gcc']
+    LIBS = ['gcc'],
+    LINKCOM = env['KERNEL_LINKCOM']
 )
 env.Depends(prog_os, env['KERNEL_DEPENDENCIES'])
 env.Default(prog_os)
 comp_db = env.CompilationDatabase(target = '#compile_commands.json')
 env.Default(comp_db)
+
+iso_targets = []
+for iso_file in env['ISO_FILES']:
+    iso_targets.append(env.Command(f'iso/{iso_file["target"]}', iso_file["source"], Copy("$TARGET", "$SOURCE")))
+env.Command('os.iso', iso_targets, 'grub-mkrescue -o "$TARGET" "iso"')

iso/.gitignore

@@ -0,0 +1,3 @@
+# staging area for iso creation
+*
+!.gitignore

targets/i686/SConscript

@@ -17,15 +17,26 @@ crtbegin_o = get_crt_object('crtbegin.o')
 crtend_o = get_crt_object('crtend.o')
 crti_o = env.Object('src/crt/crti.s')
 crtn_o = env.Object('src/crt/crtn.s')
+env['KERNEL_LINKCOM'] = env['LINKCOM'].replace('$_LIBFLAGS', f'{crti_o[0].abspath} {crtbegin_o} $_LIBFLAGS {crtend_o} {crtn_o[0].abspath}')
 
 i686_sources = Split('''
     src/kernel/boot.s
     src/kernel/startup.cpp
 ''')
 
-env['LINKCOM'] = env['LINKCOM'].replace('$_LIBFLAGS', f'{crti_o[0].abspath} {crtbegin_o} $_LIBFLAGS {crtend_o} {crtn_o[0].abspath}')
+i686_iso_files = [
+    {
+        "source": env.File("boot/grub.cfg"),
+        "target": "boot/grub/grub.cfg"
+    },
+    {
+        "source": env.File("#os.bin"),
+        "target": "boot/os.bin"
+    }
+]
 
 env.Append(KERNEL_SOURCES = [env.File(f) for f in i686_sources])
 env.Append(KERNEL_DEPENDENCIES = [crti_o, crtn_o])
+env.Append(ISO_FILES = i686_iso_files)
 
 Return('env')

targets/i686/boot/grub.cfg

@@ -1,3 +1,7 @@
+set timeout=0
+set default=0
+
 menuentry "Bad Apple OS" {
     multiboot /boot/os.bin
+    boot
 }

targets/x86_64/SConscript

@@ -18,15 +18,40 @@ crtend_o = get_crt_object('crtend.o')
 crti_o = env.Object('src/crt/crti.s')
 crtn_o = env.Object('src/crt/crtn.s')
 
-i686_sources = Split('''
+x86_64_sources = Split('''
-    src/kernel/boot.s
     src/kernel/startup.cpp
 ''')
 
-env['LINKCOM'] = env['LINKCOM'].replace('$_LIBFLAGS', f'{crti_o[0].abspath} {crtbegin_o} $_LIBFLAGS {crtend_o} {crtn_o[0].abspath}')
+env['KERNEL_LINKCOM'] = env['LINKCOM'].replace('$_LIBFLAGS', f'{crti_o[0].abspath} {crtbegin_o} $_LIBFLAGS {crtend_o} {crtn_o[0].abspath}')
 
-env.Append(KERNEL_SOURCES = [env.File(f) for f in i686_sources])
+x86_64_iso_files = [
-env.Append(KERNEL_DEPENDENCIES = [crti_o, crtn_o])
+    {
+        "source": env.File("boot/grub.cfg"),
+        "target": "boot/grub/grub.cfg"
+    },
+    {
+        "source": env.File("#os.bin"),
+        "target": "boot/os.bin"
+    },
+    {
+        "source": env.File("#loader.bin"),
+        "target": "boot/loader.bin"
+    }
+]
+
+# also compile the loader (as i686-elf)
+loader_sources = Split('''
+    src/loader/boot.asm
+''')
+nasm_include_dir = env.Dir('src/loader')
+prog_loader = env.Command(
+    '#loader.bin', 'src/loader/boot.asm', f'nasm -I"{nasm_include_dir.abspath}" "$SOURCE" -f bin -o "$TARGET"'
+)
+
+# finally update the environment
+env.Append(KERNEL_SOURCES = [env.File(f) for f in x86_64_sources])
+env.Append(KERNEL_DEPENDENCIES = [crti_o, crtn_o, prog_loader])
 env.Append(LINKFLAGS = ['-mcmodel=large', '-mno-red-zone', '-mno-mmx', '-mno-sse', '-mno-sse2'])
+env.Append(ISO_FILES = x86_64_iso_files)
 
 Return('env')

targets/x86_64/boot/grub.cfg

@@ -0,0 +1,8 @@
+set timeout=0
+set default=0
+
+menuentry "Bad Apple OS" {
+    multiboot /boot/loader.bin
+    module /boot/os.bin ""
+    boot
+}

targets/x86_64/src/loader/boot.asm

@@ -0,0 +1,37 @@
+
+;;; Code
+[ORG 0x7c00] ; this is where NASM expects the code to be located (important for offsets and addresses)
+    jmp start
+
+%include "print.inc"
+
+start:
+    xor ax, ax ; sets AX to 0
+    mov ds, ax ; writes the 0 to DS (you can't directly write to DS) DS points to the "data segment"
+    mov ss, ax ; same as above, but now for the "stack segment"
+    mov sp, 0x9c00 ; initialize the stack
+    cld ; clear the direction flag (so lodsb increments si and doesn't decrement it)
+
+    mov ax, 0xb800 ; text video memory
+    mov es, ax ; store inside ES (extended segment), used later by stosw
+
+    call clear_screen
+
+    mov si, msg ; set the SI (source index) register to our string
+    call print_string
+
+;;; The end of it
+hang:
+    jmp hang
+
+;;; Data
+msg db 'Hello World', 0
+terminal_posx db 0 ; X position for writing text
+terminal_posy db 0 ; Y position for writing text
+
+;;; Padding and Signature
+times 510-($-$$) db 0
+
+; boot signature (so QEMU boots this)
+db 0x55
+db 0xAA

targets/x86_64/src/loader/loader.c

@@ -0,0 +1,20 @@
+
+#include <stdint.h>
+#include "multiboot.h"
+
+void load_kernel_module(const multiboot_module_t* module)
+{
+    
+}
+
+void loader_main(const multiboot_info_t* multibootInfo)
+{
+    if (multibootInfo->flags & MULTIBOOT_INFO_MODS)
+    {
+        const multiboot_module_t* modules = (multiboot_module_t*) multibootInfo->mods_addr;
+        for (uint32_t modIdx = 0; modIdx < multibootInfo->mods_count; ++modIdx)
+        {
+            load_kernel_module(&modules[modIdx]);
+        }
+    }
+}

targets/x86_64/src/loader/multiboot.h

@@ -0,0 +1,274 @@
+/* multiboot.h - Multiboot header file. */
+/* Copyright (C) 1999,2003,2007,2008,2009,2010  Free Software Foundation, Inc.
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy
+ *  of this software and associated documentation files (the "Software"), to
+ *  deal in the Software without restriction, including without limitation the
+ *  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ *  sell copies of the Software, and to permit persons to whom the Software is
+ *  furnished to do so, subject to the following conditions:
+ *
+ *  The above copyright notice and this permission notice shall be included in
+ *  all copies or substantial portions of the Software.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL ANY
+ *  DEVELOPER OR DISTRIBUTOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+ *  IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef MULTIBOOT_HEADER
+#define MULTIBOOT_HEADER 1
+
+/* How many bytes from the start of the file we search for the header. */
+#define MULTIBOOT_SEARCH                        8192
+#define MULTIBOOT_HEADER_ALIGN                  4
+
+/* The magic field should contain this. */
+#define MULTIBOOT_HEADER_MAGIC                  0x1BADB002
+
+/* This should be in %eax. */
+#define MULTIBOOT_BOOTLOADER_MAGIC              0x2BADB002
+
+/* Alignment of multiboot modules. */
+#define MULTIBOOT_MOD_ALIGN                     0x00001000
+
+/* Alignment of the multiboot info structure. */
+#define MULTIBOOT_INFO_ALIGN                    0x00000004
+
+/* Flags set in the ’flags’ member of the multiboot header. */
+
+/* Align all boot modules on i386 page (4KB) boundaries. */
+#define MULTIBOOT_PAGE_ALIGN                    0x00000001
+
+/* Must pass memory information to OS. */
+#define MULTIBOOT_MEMORY_INFO                   0x00000002
+
+/* Must pass video information to OS. */
+#define MULTIBOOT_VIDEO_MODE                    0x00000004
+
+/* This flag indicates the use of the address fields in the header. */
+#define MULTIBOOT_AOUT_KLUDGE                   0x00010000
+
+/* Flags to be set in the ’flags’ member of the multiboot info structure. */
+
+/* is there basic lower/upper memory information? */
+#define MULTIBOOT_INFO_MEMORY                   0x00000001
+/* is there a boot device set? */
+#define MULTIBOOT_INFO_BOOTDEV                  0x00000002
+/* is the command-line defined? */
+#define MULTIBOOT_INFO_CMDLINE                  0x00000004
+/* are there modules to do something with? */
+#define MULTIBOOT_INFO_MODS                     0x00000008
+
+/* These next two are mutually exclusive */
+
+/* is there a symbol table loaded? */
+#define MULTIBOOT_INFO_AOUT_SYMS                0x00000010
+/* is there an ELF section header table? */
+#define MULTIBOOT_INFO_ELF_SHDR                 0X00000020
+
+/* is there a full memory map? */
+#define MULTIBOOT_INFO_MEM_MAP                  0x00000040
+
+/* Is there drive info? */
+#define MULTIBOOT_INFO_DRIVE_INFO               0x00000080
+
+/* Is there a config table? */
+#define MULTIBOOT_INFO_CONFIG_TABLE             0x00000100
+
+/* Is there a boot loader name? */
+#define MULTIBOOT_INFO_BOOT_LOADER_NAME         0x00000200
+
+/* Is there a APM table? */
+#define MULTIBOOT_INFO_APM_TABLE                0x00000400
+
+/* Is there video information? */
+#define MULTIBOOT_INFO_VBE_INFO                 0x00000800
+#define MULTIBOOT_INFO_FRAMEBUFFER_INFO         0x00001000
+
+#ifndef ASM_FILE
+
+typedef unsigned char           multiboot_uint8_t;
+typedef unsigned short          multiboot_uint16_t;
+typedef unsigned int            multiboot_uint32_t;
+typedef unsigned long long      multiboot_uint64_t;
+
+struct multiboot_header
+{
+    /* Must be MULTIBOOT_MAGIC - see above. */
+    multiboot_uint32_t magic;
+
+    /* Feature flags. */
+    multiboot_uint32_t flags;
+
+    /* The above fields plus this one must equal 0 mod 2^32. */
+    multiboot_uint32_t checksum;
+
+    /* These are only valid if MULTIBOOT_AOUT_KLUDGE is set. */
+    multiboot_uint32_t header_addr;
+    multiboot_uint32_t load_addr;
+    multiboot_uint32_t load_end_addr;
+    multiboot_uint32_t bss_end_addr;
+    multiboot_uint32_t entry_addr;
+
+    /* These are only valid if MULTIBOOT_VIDEO_MODE is set. */
+    multiboot_uint32_t mode_type;
+    multiboot_uint32_t width;
+    multiboot_uint32_t height;
+    multiboot_uint32_t depth;
+};
+
+/* The symbol table for a.out. */
+struct multiboot_aout_symbol_table
+{
+    multiboot_uint32_t tabsize;
+    multiboot_uint32_t strsize;
+    multiboot_uint32_t addr;
+    multiboot_uint32_t reserved;
+};
+typedef struct multiboot_aout_symbol_table multiboot_aout_symbol_table_t;
+
+/* The section header table for ELF. */
+struct multiboot_elf_section_header_table
+{
+    multiboot_uint32_t num;
+    multiboot_uint32_t size;
+    multiboot_uint32_t addr;
+    multiboot_uint32_t shndx;
+};
+typedef struct multiboot_elf_section_header_table multiboot_elf_section_header_table_t;
+
+struct multiboot_info
+{
+    /* Multiboot info version number */
+    multiboot_uint32_t flags;
+
+    /* Available memory from BIOS */
+    multiboot_uint32_t mem_lower;
+    multiboot_uint32_t mem_upper;
+
+    /* "root" partition */
+    multiboot_uint32_t boot_device;
+
+    /* Kernel command line */
+    multiboot_uint32_t cmdline;
+
+    /* Boot-Module list */
+    multiboot_uint32_t mods_count;
+    multiboot_uint32_t mods_addr;
+
+    union
+    {
+        multiboot_aout_symbol_table_t aout_sym;
+        multiboot_elf_section_header_table_t elf_sec;
+    } u;
+
+    /* Memory Mapping buffer */
+    multiboot_uint32_t mmap_length;
+    multiboot_uint32_t mmap_addr;
+
+    /* Drive Info buffer */
+    multiboot_uint32_t drives_length;
+    multiboot_uint32_t drives_addr;
+
+    /* ROM configuration table */
+    multiboot_uint32_t config_table;
+
+    /* Boot Loader Name */
+    multiboot_uint32_t boot_loader_name;
+
+    /* APM table */
+    multiboot_uint32_t apm_table;
+
+    /* Video */
+    multiboot_uint32_t vbe_control_info;
+    multiboot_uint32_t vbe_mode_info;
+    multiboot_uint16_t vbe_mode;
+    multiboot_uint16_t vbe_interface_seg;
+    multiboot_uint16_t vbe_interface_off;
+    multiboot_uint16_t vbe_interface_len;
+
+    multiboot_uint64_t framebuffer_addr;
+    multiboot_uint32_t framebuffer_pitch;
+    multiboot_uint32_t framebuffer_width;
+    multiboot_uint32_t framebuffer_height;
+    multiboot_uint8_t framebuffer_bpp;
+#define MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED 0
+#define MULTIBOOT_FRAMEBUFFER_TYPE_RGB     1
+#define MULTIBOOT_FRAMEBUFFER_TYPE_EGA_TEXT     2
+    multiboot_uint8_t framebuffer_type;
+    union
+    {
+        struct
+        {
+            multiboot_uint32_t framebuffer_palette_addr;
+            multiboot_uint16_t framebuffer_palette_num_colors;
+        };
+        struct
+        {
+            multiboot_uint8_t framebuffer_red_field_position;
+            multiboot_uint8_t framebuffer_red_mask_size;
+            multiboot_uint8_t framebuffer_green_field_position;
+            multiboot_uint8_t framebuffer_green_mask_size;
+            multiboot_uint8_t framebuffer_blue_field_position;
+            multiboot_uint8_t framebuffer_blue_mask_size;
+        };
+    };
+};
+typedef struct multiboot_info multiboot_info_t;
+
+struct multiboot_color
+{
+    multiboot_uint8_t red;
+    multiboot_uint8_t green;
+    multiboot_uint8_t blue;
+};
+
+struct multiboot_mmap_entry
+{
+    multiboot_uint32_t size;
+    multiboot_uint64_t addr;
+    multiboot_uint64_t len;
+#define MULTIBOOT_MEMORY_AVAILABLE              1
+#define MULTIBOOT_MEMORY_RESERVED               2
+#define MULTIBOOT_MEMORY_ACPI_RECLAIMABLE       3
+#define MULTIBOOT_MEMORY_NVS                    4
+#define MULTIBOOT_MEMORY_BADRAM                 5
+    multiboot_uint32_t type;
+} __attribute__((packed));
+typedef struct multiboot_mmap_entry multiboot_memory_map_t;
+
+struct multiboot_mod_list
+{
+    /* the memory used goes from bytes ’mod_start’ to ’mod_end-1’ inclusive */
+    multiboot_uint32_t mod_start;
+    multiboot_uint32_t mod_end;
+
+    /* Module command line */
+    multiboot_uint32_t cmdline;
+
+    /* padding to take it to 16 bytes (must be zero) */
+    multiboot_uint32_t pad;
+};
+typedef struct multiboot_mod_list multiboot_module_t;
+
+/* APM BIOS info. */
+struct multiboot_apm_info
+{
+    multiboot_uint16_t version;
+    multiboot_uint16_t cseg;
+    multiboot_uint32_t offset;
+    multiboot_uint16_t cseg_16;
+    multiboot_uint16_t dseg;
+    multiboot_uint16_t flags;
+    multiboot_uint16_t cseg_len;
+    multiboot_uint16_t cseg_16_len;
+    multiboot_uint16_t dseg_len;
+};
+
+#endif /* ! ASM_FILE */
+
+#endif /* ! MULTIBOOT_HEADER */

targets/x86_64/src/loader/print.inc

@@ -0,0 +1,70 @@
+
+;;; Procedure to print a text on the screen. Takes the address of a 0-terminated string in the SI register.
+print_string:
+print_string_loop:
+    lodsb ; load whatever is at SI to AL and increment SI
+    or al, al ; check if AL is 0
+    jz print_string_loop_done ; if AL is 0, go to the end
+
+    call print_char ; print the character in AL
+    jmp print_string_loop
+
+print_string_loop_done:
+    add byte [terminal_posy], 1 ; next row
+    mov byte [terminal_posx], 0 ; back to the left
+    ret
+
+;;; Procedure to print a single character. Takes the character in the AL register.
+print_char:
+    mov ah, 0x0F ; set the higher half of AX to white on black color
+    mov cx, ax ; preserve the content for later
+
+    ; now calculate the memory offset for the Y position
+    movzx ax, byte [terminal_posy] ; first load the Y position
+    mov dx, 160 ; then multiply it with 160 (2 bytes per char, 80 columns)
+    mul dx ; stores the result in AX
+
+    ; next calculate the offset for the X position
+    movzx bx, byte [terminal_posx] ; load the X position
+    shl bx, 1 ; multiply by 2 (2 bytes per char)
+
+    ; finally add the two
+    mov di, 0
+    add di, ax ; y offset
+    add di, bx ; x offset
+
+    ; restore the character and write it
+    mov ax, cx
+    stosw
+
+    ; advance the X position and done
+    add byte [terminal_posx], 1
+    ret
+
+;;; Procedure to clear the screen (set everything to 0)
+clear_screen:
+    mov ax, 0
+    mov di, 0
+clear_screen_loop:
+    stosw ; write the 0 (2 bytes at a time)
+    cmp di, 2 * 25 * 60 ; check if we cleaned all 80 * 60 * 2 bytes
+    jne clear_screen_loop ; if not, repeat
+    mov byte [terminal_posx], 0
+    mov byte [terminal_posy], 0
+    ret
+
+; ;;; Procedure to print a text on the using the BIOS. Takes the address to a 0-terminated string in the SI register.
+; bios_print:
+; bios_print_loop:
+;     lodsb ; load whatever is at SI to AL and increment SI
+;     or al, al ; check if AL is 0
+;     jz bios_print_done ; if AL is 0, go to the end
+;
+;     ; invoke Int 10/AH=0Eh (VIDEO - TELETYPE OUTPUT)
+;     ; Takes a character from AL, writes it to the screen and advances the cursor.
+;     mov ah, 0x0E
+;     mov bh, 0
+;     int 0x10
+;     jmp bios_print_loop ; next char
+; bios_print_done:
+;     ret