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|
use crate::io::*;
use lazy_static::lazy_static;
// provide functions to parse information provided by grub multiboot
// see docs/multiboot.txt
extern "C" {
static mb_magic: u32;
static mb_info_addr: u32;
}
lazy_static! {
pub static ref MBOOTINFO: &'static MultibootInfo =
unsafe { &*(mb_info_addr as *const MultibootInfo) };
}
/// this must be checked before any MB info fields are used.
pub fn check() -> bool {
if unsafe { mb_magic != 0x2BADB002 } {
return false;
};
// must check magic before checking flags
let f = MBOOTINFO.get_flags();
return f.check_valid();
}
#[repr(C)]
#[repr(packed)]
#[derive(Debug)]
pub struct MultibootMmap {
pub size: u32,
pub addr: u64,
pub len: u64,
pub mtype: u32,
}
#[repr(C)]
#[repr(packed)]
#[derive(Debug, Clone, Copy)]
pub struct MultibootInfoMmap {
pub mmap_length: u32,
pub mmap_addr: u32,
}
#[repr(C)]
#[repr(packed)]
#[derive(Debug, Clone, Copy)]
pub struct MultibootInfoMem {
mem_lower: u32,
mem_upper: u32,
}
#[repr(C)]
#[repr(packed)]
#[derive(Debug)]
/// all fields MUST be acquired via unsafe getters, because the MB magic and reserved bits in flags
/// must be checked for validity before using. It does not suffice to check the corresponding
/// present bits in the getters.
/// Some fields are marked as padding because we don't need them (for now)
pub struct MultibootInfo {
flags: MultibootInfoFlags,
mem: MultibootInfoMem,
_pad1: [u8; 32],
mmap: MultibootInfoMmap,
_pad2: [u8; 68],
}
impl MultibootInfo {
// private function. Don't use it outside the module.
fn get_flags(&self) -> MultibootInfoFlags {
return self.flags;
}
pub unsafe fn get_mem(&self) -> Option<MultibootInfoMem> {
if self.get_flags().contains(MultibootInfoFlags::MEM) {
return Some(self.mem);
} else {
return None;
}
}
pub unsafe fn get_mmap(&self) -> Option<MultibootInfoMmap> {
if self.get_flags().contains(MultibootInfoFlags::MMAP) {
return Some(self.mmap);
} else {
return None;
}
}
}
use bitflags::bitflags;
bitflags! {
/// the MultibootInfoFlags indicate which fields are valid in the MultibootInfo
/// atm we only need the MEM and MMAP flags for memory management info.
#[derive(Copy, Clone, Debug)]
pub struct MultibootInfoFlags: u32 {
const MEM = 1 << 0;
const BOOT_DEVICE = 1 << 1;
const CMDLINE = 1 << 2;
const MODS = 1 << 3;
const SYM_TBL = 1 << 4;
const SHDR = 1 << 5;
const MMAP = 1 << 6;
const DRIVES = 1 << 7;
const CONF_TBL = 1 << 8;
const BL_NAME = 1 << 9;
const APM_TBL = 1 << 10;
const VBE_TBL = 1 << 11;
const FRAMEBUFFER = 1 << 12;
}
}
impl MultibootInfoFlags {
/// only 13 bits of the MB info flags are defined. The other flag bits must
/// be zero for the info block to be valie.
const VALID_MASK: u32 = 0x1FFF;
pub fn check_valid(&self) -> bool {
return self.bits() <= Self::VALID_MASK;
}
}
pub fn get_mb_info() -> Option<&'static MultibootInfo> {
if !check() {
return None;
}
return Some(&MBOOTINFO);
}
// TODO: expand MultibootInfo struct defs if needed.
|
