| // Copyright 2024 The ChromiumOS Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| //! Multiboot specification 0.6.96 definitions |
| //! |
| //! <https://www.gnu.org/software/grub/manual/multiboot/multiboot.html> |
| |
| use zerocopy::FromBytes; |
| use zerocopy::Immutable; |
| use zerocopy::IntoBytes; |
| use zerocopy::KnownLayout; |
| |
| /// Magic value stored in EAX to indicate bootloader is Multiboot compliant. |
| pub const MULTIBOOT_BOOTLOADER_MAGIC: u32 = 0x2BADB002; |
| |
| #[derive(Debug, Default, FromBytes, Immutable, IntoBytes, KnownLayout)] |
| #[repr(C, packed)] |
| pub struct MultibootInfo { |
| pub flags: u32, |
| |
| pub mem_lower: u32, |
| pub mem_upper: u32, |
| |
| pub boot_device: u32, |
| |
| pub cmdline: u32, |
| |
| pub mods_count: u32, |
| pub mods_addr: u32, |
| |
| // TODO: add union for ELF + a.out symbols if needed |
| pub syms: [u32; 4], |
| |
| pub mmap_length: u32, |
| pub mmap_addr: u32, |
| |
| pub drives_length: u32, |
| pub drives_addr: u32, |
| |
| pub config_table: u32, |
| |
| pub boot_loader_name: u32, |
| |
| pub apm_table: u32, |
| |
| pub vbe_control_info: u32, |
| pub vbe_mode_info: u32, |
| pub vbe_mode: u16, |
| pub vbe_interface_seg: u16, |
| pub vbe_interface_off: u16, |
| pub vbe_interface_len: u16, |
| |
| pub framebuffer_addr: u64, |
| pub framebuffer_pitch: u32, |
| pub framebuffer_width: u32, |
| pub framebuffer_height: u32, |
| pub framebuffer_bpp: u8, |
| pub framebuffer_type: u8, |
| |
| // TODO: add union for palette + RGB color info if needed |
| pub color_info: [u8; 6], |
| } |
| |
| impl MultibootInfo { |
| pub const F_MEM: u32 = 1 << 0; |
| pub const F_BOOT_DEVICE: u32 = 1 << 1; |
| pub const F_CMDLINE: u32 = 1 << 2; |
| pub const F_MODS: u32 = 1 << 3; |
| pub const F_SYMS_AOUT: u32 = 1 << 4; |
| pub const F_SYMS_ELF: u32 = 1 << 5; |
| pub const F_MMAP: u32 = 1 << 6; |
| pub const F_DRIVES: u32 = 1 << 7; |
| pub const F_CONFIG_TABLE: u32 = 1 << 8; |
| pub const F_BOOT_LOADER_NAME: u32 = 1 << 9; |
| pub const F_APM_TABLE: u32 = 1 << 10; |
| pub const F_VBE: u32 = 1 << 11; |
| pub const F_FRAMEBUFFER: u32 = 1 << 12; |
| } |
| |
| #[derive(Debug, Default, FromBytes, Immutable, IntoBytes, KnownLayout)] |
| #[repr(C, packed)] |
| pub struct MultibootMmapEntry { |
| pub size: u32, |
| pub base_addr: u64, |
| pub length: u64, |
| pub type_: u32, |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use std::mem::offset_of; |
| use std::mem::size_of; |
| |
| use super::*; |
| |
| #[test] |
| fn test_multiboot_info_offsets() { |
| // Validate that multiboot_info field offsets match the spec. |
| assert_eq!(0, offset_of!(MultibootInfo, flags)); |
| assert_eq!(4, offset_of!(MultibootInfo, mem_lower)); |
| assert_eq!(8, offset_of!(MultibootInfo, mem_upper)); |
| assert_eq!(8, offset_of!(MultibootInfo, mem_upper)); |
| assert_eq!(12, offset_of!(MultibootInfo, boot_device)); |
| assert_eq!(16, offset_of!(MultibootInfo, cmdline)); |
| assert_eq!(20, offset_of!(MultibootInfo, mods_count)); |
| assert_eq!(24, offset_of!(MultibootInfo, mods_addr)); |
| assert_eq!(28, offset_of!(MultibootInfo, syms)); |
| assert_eq!(44, offset_of!(MultibootInfo, mmap_length)); |
| assert_eq!(48, offset_of!(MultibootInfo, mmap_addr)); |
| assert_eq!(52, offset_of!(MultibootInfo, drives_length)); |
| assert_eq!(56, offset_of!(MultibootInfo, drives_addr)); |
| assert_eq!(60, offset_of!(MultibootInfo, config_table)); |
| assert_eq!(64, offset_of!(MultibootInfo, boot_loader_name)); |
| assert_eq!(68, offset_of!(MultibootInfo, apm_table)); |
| assert_eq!(72, offset_of!(MultibootInfo, vbe_control_info)); |
| assert_eq!(76, offset_of!(MultibootInfo, vbe_mode_info)); |
| assert_eq!(80, offset_of!(MultibootInfo, vbe_mode)); |
| assert_eq!(82, offset_of!(MultibootInfo, vbe_interface_seg)); |
| assert_eq!(84, offset_of!(MultibootInfo, vbe_interface_off)); |
| assert_eq!(86, offset_of!(MultibootInfo, vbe_interface_len)); |
| assert_eq!(88, offset_of!(MultibootInfo, framebuffer_addr)); |
| assert_eq!(96, offset_of!(MultibootInfo, framebuffer_pitch)); |
| assert_eq!(100, offset_of!(MultibootInfo, framebuffer_width)); |
| assert_eq!(104, offset_of!(MultibootInfo, framebuffer_height)); |
| assert_eq!(108, offset_of!(MultibootInfo, framebuffer_bpp)); |
| assert_eq!(109, offset_of!(MultibootInfo, framebuffer_type)); |
| assert_eq!(110, offset_of!(MultibootInfo, color_info)); |
| |
| assert_eq!(size_of::<MultibootInfo>(), 116); |
| } |
| |
| #[test] |
| fn test_multiboot_mmap_entry_offsets() { |
| // The spec defines the mmap entry structure in a confusing way (`size` at offset -4 and |
| // `base_addr` at offset 0), but this does not match how both bootloaders and kernels have |
| // implemented Multiboot (`size` at offset 0), so this does not exactly match the table in |
| // the spec. |
| assert_eq!(0, offset_of!(MultibootMmapEntry, size)); |
| assert_eq!(4, offset_of!(MultibootMmapEntry, base_addr)); |
| assert_eq!(12, offset_of!(MultibootMmapEntry, length)); |
| assert_eq!(20, offset_of!(MultibootMmapEntry, type_)); |
| |
| assert_eq!(size_of::<MultibootMmapEntry>(), 24); // 20-byte e820 data + 4 bytes for size |
| } |
| } |
