1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70
//! Provides boot information to the kernel.
#![deny(improper_ctypes)]
pub use self::memory_map::*;
mod memory_map;
/// This structure represents the information that the bootloader passes to the kernel.
///
/// The information is passed as an argument to the entry point:
///
/// ```ignore
/// pub extern "C" fn _start(boot_info: &'static BootInfo) -> ! {
/// // […]
/// }
/// ```
///
/// Note that no type checking occurs for the entry point function, so be careful to
/// use the correct argument types. To ensure that the entry point function has the correct
/// signature, use the [`entry_point`] macro.
#[derive(Debug)]
#[repr(C)]
pub struct BootInfo {
/// A map of the physical memory regions of the underlying machine.
///
/// The bootloader queries this information from the BIOS/UEFI firmware and translates this
/// information to Rust types. It also marks any memory regions that the bootloader uses in
/// the memory map before passing it to the kernel. Regions marked as usable can be freely
/// used by the kernel.
pub memory_map: MemoryMap,
/// The virtual address of the recursively mapped level 4 page table.
#[cfg(feature = "recursive_page_table")]
pub recursive_page_table_addr: u64,
/// The offset into the virtual address space where the physical memory is mapped.
///
/// Physical addresses can be converted to virtual addresses by adding this offset to them.
///
/// The mapping of the physical memory allows to access arbitrary physical frames. Accessing
/// frames that are also mapped at other virtual addresses can easily break memory safety and
/// cause undefined behavior. Only frames reported as `USABLE` by the memory map in the `BootInfo`
/// can be safely accessed.
#[cfg(feature = "map_physical_memory")]
pub physical_memory_offset: u64,
_non_exhaustive: u8, // `()` is not FFI safe
}
impl BootInfo {
/// Create a new boot information structure. This function is only for internal purposes.
#[allow(unused_variables)]
#[doc(hidden)]
pub fn new(
memory_map: MemoryMap,
recursive_page_table_addr: u64,
physical_memory_offset: u64,
) -> Self {
BootInfo {
memory_map,
#[cfg(feature = "recursive_page_table")]
recursive_page_table_addr,
#[cfg(feature = "map_physical_memory")]
physical_memory_offset,
_non_exhaustive: 0,
}
}
}
extern "C" {
fn _improper_ctypes_check(_boot_info: BootInfo);
}