Embedded Rust on RISC-V Part 1

Bootstrap RISC-V target

Jul 2, 2025 - 16:40 Updated: Jul 14, 2025 - 12:35
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Embedded Rust on RISC-V Part 1
Embedded Rust on RISC-V Part 1

Embedded Rust on RISC-V Part 1 free download

Bootstrap RISC-V target

First and foremost, this course don't cover toolchain installation This course starts with building blocks needed to bootstrap RISC-V processor into rust and finishes by booting Hifive1-Rev B board into Embedded Rust. Regarding the code management, there are many ways to manage code in rust; this course adopts Cargo workspace.


Section 1: Introduction

  • Introduction

  • Preamble

  • What is covered & what isn't

  • Resources & expectation


Section 2: Cargo Workspace

  • Create Cargo workspace

  • Create a binary crate to build an executable

  • Create library crate to keep reusable code

  • Create Cargo.toml to manage dependencies


Then this course jumps into the Embedded-rust & Cargo settings.

Section 3: Embedded-rust and Cargo settings for RISC-V Embedded Rust target

  • What are attributes in Rust?

  • What is Embedded Rust?

  • Provide custom panic handler and entry function

  • The difference between Cargo toml file vs config file

  • How to configure Cargo Workspace to build for RISC-V instead of host?

  • How to pass additional flags to Rust compiler?

  • How to pass custom linker file for target (Hifive1-RevB board)?

NOTE: This course don't cover how to write linker file. However, the linker file is shared as downloadable resource.


Section 4: Commands to dissect ELF and RUSTFLAGS

  • Commands to extract information from ELF

  • RUSTFLAGS in rust to tweak compiler behaviour

  • How to add custom linker file with RUSTFLAGS


With workspace & code management taken care, next is to add RISC-V boot up code in RISC-V assembly.

Section 5: Simple RISC-V boot code   (Binary Crate)

  • How to add a assembly (.S) file?

  • Disable interrupts at boot time

  • Set the stack pointer to valid location

  • How to jump from RISC-V assembly to Embedded Rust entry function?

  • Build an executable with boot code in RISC-V assembly with entry & panic handler in Rust


Section 6: UART Driver in Rust  (Library Crate)

  • Structs and Impls in Rust

  • Uart driver functions

  • Build an executable with boot code in RISC-V asm and UART driver in Rust.

  • Connect to Hifive1-RevB board with OpenOCD & GDB server

  • Load the executable into Hifive1-RevB

  • Read messages from serial out with serial tools

NOTE: This section uses a OpenOCD script but don't discuss about the script content. However, the script is shared as downloadable resource. 


Update on Dec 5, 2024:  Attached boot.S file on Section #5

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