feat(loader, kernel): impl part of loader and initialize kernel structure

arch/x86_64/boot/multiboot.zig

@@ -0,0 +1,250 @@
+const std = @import("std");
+const BootParams = @import("params.zig").BootParams;
+pub const MULTIBOOT_TAG_ALIGN: usize = 8;
+pub const MultibootTagType = enum(u32) {
+    end,
+	cmdline,
+	boot_loader_name,
+	module,
+	basic_meminfo,
+	bootdev,
+	mmap,
+	vbe,
+	framebuffer,
+	elf_sections,
+	apm,
+	efi32,
+	efi64,
+	smbios,
+	acpi_old,
+	acpi_new,
+	network,
+	efi_mmap,
+	efi_bs,
+	efi32_ih,
+	efi64_ih,
+	load_base_addr,
+};
+
+pub const MultibootTag = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+};
+
+pub const MultibootTagCmdline = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    string: [0]u8 align(1),
+};
+
+pub const MultibootTagModule = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    mod_start: u32 align(1),
+    mod_end: u32 align(1),
+    cmdline: [0]u8 align(1),
+};
+
+pub const MultibootTagBasicMeminfo = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    mem_lower: u32 align(1),
+    mem_upper: u32 align(1),
+};
+
+pub const MultibootTagBootdev = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    biosdev: u32 align(1),
+    slice: u32 align(1),
+    part: u32 align(1),
+};
+
+pub const MultibootMmapEntry = extern struct {
+    addr: u64 align(1),
+    len: u64 align(1),
+    type: u32 align(1),
+    zero: u32 align(1),
+};
+
+pub const MultibootTagMmap = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    entry_size: u32 align(1),
+    entry_version: u32 align(1),
+    entries: [0]MultibootMmapEntry align(1),
+};
+
+pub const MultibootVbeInfoBlock = extern struct {
+    external_specification: [512]u8 align(1),
+};
+
+pub const MultibootVbeModeInfoBlock = extern struct {
+    external_specification: [256]u8 align(1),
+};
+
+pub const MultibootTagVbe = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+
+    vbe_mode: u16 align(1),
+    vbe_interface_seg: u16 align(1),
+    vbe_interface_off: u16 align(1),
+    vbe_interface_len: u16 align(1),
+
+    vbe_control_info: MultibootVbeInfoBlock align(1),
+    vbe_mode_info: MultibootVbeModeInfoBlock align(1),
+};
+
+pub const MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED = 0;
+pub const MULTIBOOT_FRAMEBUFFER_TYPE_RGB = 1;
+pub const MULTIBOOT_FRAMEBUFFER_TYPE_EGA_TEXT = 2;
+
+pub const MultibootColor = extern struct {
+    red: u8 align(1),
+    green: u8 align(1),
+    blue: u8 align(1),
+};
+
+pub const MultibootTagFramebufferCommon = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+
+    framebuffer_addr: u64 align(1),
+    framebuffer_pitch: u32 align(1),
+    framebuffer_width: u32 align(1),
+    framebuffer_height: u32 align(1),
+    framebuffer_bpp: u8 align(1),
+    framebuffer_type: u8 align(1),
+    reserved: u16 align(1),
+};
+
+pub const MultibootTagFramebuffer = extern struct {
+    common: MultibootTagFramebufferCommon align(1),
+
+    details: extern union {
+        indexed: extern struct {
+            framebuffer_palette_num_colors: u16 align(1),
+            framebuffer_palette: [*]MultibootColor align(1),
+        } align(1),
+        rgb: extern struct {
+            framebuffer_red_field_position: u8 align(1),
+            framebuffer_red_mask_size: u8 align(1),
+            framebuffer_green_field_position: u8 align(1),
+            framebuffer_green_mask_size: u8 align(1),
+            framebuffer_blue_field_position: u8 align(1),
+            framebuffer_blue_mask_size: u8 align(1),
+        } align(1),
+    } align(1),
+};
+
+pub const MultibootTagElfSections = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    num: u32 align(1),
+    entsize: u32 align(1),
+    shndx: u32 align(1),
+    sections: [*]u8 align(1),
+};
+
+pub const MultibootTagApm = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    version: u16 align(1),
+    cseg: u16 align(1),
+    offset: u32 align(1),
+    cseg_16: u16 align(1),
+    dseg: u16 align(1),
+    flags: u16 align(1),
+    cseg_len: u16 align(1),
+    cseg_16_len: u16 align(1),
+    dseg_len: u16 align(1),
+};
+
+pub const MultibootTagEfi32 = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    pointer: u32 align(1),
+};
+
+pub const MultibootTagEfi64 = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    pointer: u64 align(1),
+};
+
+pub const MultibootTagSmbios = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    major: u8 align(1),
+    minor: u8 align(1),
+    reserved: [6]u8 align(1),
+    tables: [*]u8 align(1),
+};
+
+pub const MultibootTagOldAcpi = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    rsdp: [*]u8 align(1),
+};
+
+pub const MultibootTagNewAcpi = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    rsdp: [*]u8 align(1),
+};
+
+pub const MultibootTagNetwork = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    dhcpack: [*]u8 align(1),
+};
+
+pub const MultibootTagEfiMmap = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    descr_size: u32 align(1),
+    descr_vers: u32 align(1),
+    efi_mmap: [*]u8 align(1),
+};
+
+pub const MultibootTagEfi32Ih = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    pointer: u32 align(1),
+};
+
+pub const MultibootTagEfi64Ih = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    pointer: u64 align(1),
+};
+
+pub const MultibootTagLoadBaseAddr = extern struct {
+    type: u32 align(1),
+    size: u32 align(1),
+    load_base_addr: u32 align(1),
+};
+
+pub fn parseMultibootInfo(multiboot_info: *u8) BootParams {
+    var params = BootParams{
+        .cmdline = &[_]u8{},
+    };
+    var offset: usize = @sizeOf(MultibootTag);
+    while (true) {
+        const tag: *MultibootTag = @ptrFromInt(@intFromPtr(multiboot_info) + offset);
+        if (tag.type == @intFromEnum(MultibootTagType.end)) {
+            break;
+        }
+        switch (@as(MultibootTagType, @enumFromInt(tag.type))) {
+            MultibootTagType.cmdline => {
+                const cmdline_tag: *MultibootTagCmdline = @ptrCast(tag);
+                const sentinel_cmdline = @as([*:0]u8, @ptrCast(&cmdline_tag.string));
+                params.cmdline = sentinel_cmdline[0..std.mem.len(sentinel_cmdline)];
+            },
+            else => {},
+        }
+        offset += (tag.size + MULTIBOOT_TAG_ALIGN - 1) & ~(MULTIBOOT_TAG_ALIGN - 1);
+    }
+    return params;
+}