#RusPiRo #raspberrypi #boot #baremetal #multicore

nightly sys no-std ruspiro-boot

Baremetal boot strapper code for the Raspberry Pi 3 to conviniently start a custom kernel within the Rust environment without the need to deal with all the initial setup like stack pointers, getting MMU setup and get all cores kicked off for processing. Supports Aarch32 and Aarch64 builds.

8 releases

new 0.3.2 Sep 13, 2020
0.3.1 Jan 25, 2020
0.3.0 Dec 19, 2019
0.2.1 Aug 30, 2019
0.0.3 Jul 29, 2019

#247 in No standard library

Download history 7/week @ 2020-05-29 17/week @ 2020-06-05 1/week @ 2020-06-12 8/week @ 2020-06-19 2/week @ 2020-06-26 15/week @ 2020-07-03 14/week @ 2020-07-10 22/week @ 2020-07-17 3/week @ 2020-07-24 26/week @ 2020-08-07 2/week @ 2020-08-14 11/week @ 2020-08-21 19/week @ 2020-08-28 29/week @ 2020-09-04 44/week @ 2020-09-11

51 downloads per month
Used in ruspiro-sdk

Apache-2.0

64KB
805 lines

Boot crate for the RusPiRo kernel

This crate provides basic boot code that - when build into a kernel crate - will be executed as soon as the Raspberry Pi powers up. As the building of this crate and finally linking into the kernel image depends on several linker symbols to be present it is recommended to use the linker script provided when bulding the kernel.

Travis-CI Status Latest Version Documentation License

Hint

The usage of this crate does only make sense when building a Raspberry Pi 3 bare metal kernel. The baremetal bootstrapping provided by this crate can be build for either Aarch32 or Aarch64 target architectures. It has been verified to cross compile from a Windows host machine successfully for both architectures and the execution is tested on a Raspberry Pi 3 B+.

Features

Feature Purpose
with_panic Implement a default panic handler
singlecore Keep all cores except one in a "parked" state so the runtime only uses a single core.
ruspiro_pi3 This is passed to the dependend crates to ensure they will be build properly for this target device.

Usage

To use this crate simply add the following lines to your Cargo.toml file: (hint: git dependency as long as the crate is not registered at crates.io)

[dependencies]
ruspiro-boot = { version = "0.3", features = ["ruspiro_pi3", "with_panic"] }

In the main rust file refer to this crate with this:

#[macro_use]
extern crate ruspiro_boot;

The usage of extern crate is mandatory to ensure the boot strapping is properly linked into the final binary.

To successfully build a bare metal binary using this crate for the boot strapping part it is highly recomended to use the linker script provided by this crate. Based on the target architecture to be built it is either link32.ld or link64.ld. To conviniently refer to the linker scripts contained in this crate it's recommended to use a specific build script in your project that copies the required file to your current project folder and could then be referred to with the RUSTFLAG -C link-arg=-T./link<aarch>.ld. The build script is a simple build.rs rust file in your project root with the following contents:

use std::{env, fs, path::Path};

fn main() {
    // copy the linker script from the boot crate to the current directory
    // so it will be invoked by the linker
    let ld_source = env::var_os("DEP_RUSPIRO_BOOT_LINKERSCRIPT")
        .expect("error in ruspiro build, `ruspiro-boot` not a dependency?")
        .to_str()
        .unwrap()
        .replace("\\", "/");
    let src_file = Path::new(&ld_source);
    let trg_file = format!(
        "{}/{}",
        env::current_dir().unwrap().display(),
        src_file.file_name().unwrap().to_str().unwrap()
    );
    println!("Copy linker script from {:?}, to {:?}", src_file, trg_file);
    fs::copy(src_file, trg_file).unwrap();
}

To get started you could check out the template projects here

License

Licensed under Apache License, Version 2.0, (LICENSE or http://www.apache.org/licenses/LICENSE-2.0)

Dependencies

~2MB
~45K SLoC