Struct BootInfo 

pub struct BootInfo {
    pub cpu_id: usize,
    pub cpu_count: usize,
    pub usable_memory: MemoryArea,
    pub initramfs: Option<MemoryArea>,
    pub cmdline: Option<&'static str>,
    pub device_source: DeviceSource,
}

Boot information structure containing essential system parameters

This structure is created during the early boot process and contains all necessary information for kernel initialization. It abstracts architecture-specific boot protocols into a common interface.

Architecture Integration

Different architectures populate this structure from their respective boot protocols:

• RISC-V: Created from FDT (Flattened Device Tree) data
• ARM/AArch64: Created from FDT or UEFI
• x86/x86_64: Created from ACPI tables or legacy BIOS structures

Usage

The BootInfo is passed to start_kernel() as the primary parameter and provides all essential information needed for kernel initialization:

#[no_mangle]
pub extern "C" fn start_kernel(boot_info: &BootInfo) -> ! {
    // Use boot_info for system initialization
    let memory = boot_info.usable_memory;
    let cpu_id = boot_info.cpu_id;
    // ...
}

Fields

cpu_id: usize

CPU/Hart ID of the boot processor Used for multicore initialization and per-CPU data structures

cpu_count: usize

Number of CPUs detected at runtime (from FDT) Used to drive SMP initialization and per-CPU resource sizing

usable_memory: MemoryArea

Usable memory area available for kernel allocation Excludes reserved regions, firmware areas, and kernel image

initramfs: Option<MemoryArea>

Optional initramfs memory area if available Contains initial root filesystem for early userspace programs

cmdline: Option<&'static str>

Optional kernel command line parameters Boot arguments passed by bootloader for kernel configuration

device_source: DeviceSource

Source of device information for hardware discovery Determines how the kernel will enumerate and initialize devices

Implementations

impl BootInfo

pub fn new( cpu_id: usize, cpu_count: usize, usable_memory: MemoryArea, initramfs: Option<MemoryArea>, cmdline: Option<&'static str>, device_source: DeviceSource, ) -> Self

Creates a new BootInfo instance with the specified parameters

Arguments

• cpu_id - ID of the boot processor/hart
• usable_memory - Memory area available for kernel allocation
• initramfs - Optional initramfs memory area
• cmdline - Optional kernel command line parameters
• device_source - Source of device information for hardware discovery

Returns

A new BootInfo instance containing the specified boot parameters

pub fn get_cmdline(&self) -> &str

Returns the kernel command line arguments

Provides access to boot parameters passed by the bootloader. Returns an empty string if no command line was provided.

Returns

Command line string slice, or empty string if none available

pub fn get_initramfs(&self) -> Option<MemoryArea>

Returns the initramfs memory area if available

The initramfs contains an initial root filesystem that can be used during early boot before mounting the real root filesystem.

Returns

Optional memory area containing the initramfs data