Embedded Rust – Rust on IoT devices

@choas#Devoxx #embeddedRust

Embedded Rust Rust on IoT devices

Lars Gregori SAP Hybris


Hybris Labs Prototypeshttps://labs.hybris.com/prototype/

https://labs.hybris.com/prototype/


MotivationFunctional IoT (http://fpiot.metasepi.org/):Imagine IoT devices are:

• connected to the internet

• developed in a short time

• storing personal data

• secure

• more intelligence

• inexpensive

Can C design IoT devices like that? No, can’t.


Agenda

• Rust Overview

• Embedded Rust

• Cross Compiling

• MCU Debugging


Rust Overview


rust-lang.org

http://rust-lang.org


rust-lang.org

Rust is a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.

http://rust-lang.org


Rust Overview

Rust FAQ


Rust FAQ

• safe, concurrent, practical system language

• “We do not intend to be 100% static, 100% safe, 100% reflective, or too dogmatic in any other sense.”

• Mozilla Servo


Rust FAQ

• multi-paradigm

• OO

• no garbage collection

• strong influences from the world of functional programming

• built on LLVM


Rust FAQ

• Cross-Platform

• Android, iOS, …

• Conditional compilation#[cfg(target_os = "macos")]


Rust Overview

Control & Safety


Control & Safety

C/C++

Safety

Control

Haskell

Go

Java

Python


Control & Safety

C/C++

Safety

Control

Haskell

Go

Java

Rust

Python


Rust Overview

Rust Concepts


Rust Concepts

• ownership, the key concept

• borrowing, and their associated feature ‘references’

• lifetimes, an advanced concept of borrowing

‘fighting with the borrow checker’

https://doc.rust-lang.org/book/

https://doc.rust-lang.org/book/ownership.html#move-semantics

https://doc.rust-lang.org/book/references-and-borrowing.html

https://doc.rust-lang.org/book/lifetimes.html


letv=vec![1,2,3];letv2=v;//…println!("v[0]is:{}",v[0]);

Ownership


letv=vec![1,2,3];letv2=v;//…println!("v[0]is:{}",v[0]);

Ownership

ERROR use of moved value: `v`


letv=vec![1,2,3];letv2=v;take_something(v2);println!("v[0]is:{}",v[0]);

Ownership

ERROR use of moved value: `v`


letv=1;letv2=v;println!("vis:{}",v);

Ownership


letv=1;letv2=v;println!("vis:{}",v);

Ownership

Copy Type

OK


fnfoo(v1:Vec<i32>,v2:Vec<i32>)->(Vec<i32>,Vec<i32>,i32){//dostuffwithv1andv2(v1,v2,42)//handbackownership,andtheresult}

letv1=vec![1,2,3];letv2=vec![1,2,3];let(v1,v2,answer)=foo(v1,v2);

Ownership


fnfoo(v1:&Vec<i32>,v2:&Vec<i32>)->i32{//dostuffwithv1andv242//returntheanswer}

letv1=vec![1,2,3];letv2=vec![1,2,3];letanswer=foo(&v1,&v2);//wecanusev1andv2here!

References and Borrowing


fnfoo(v:&Vec<i32>){v.push(5);}letv=vec![];foo(&v);



fnfoo(v:&Vec<i32>){v.push(5);}letv=vec![];foo(&v);


ERROR cannot borrow immutable borrowed content `*v` as mutable


letmutx=5;{lety=&mutx;*y+=1;}println!("{}",x);





OK: 6




mut{

}


References and BorrowingThe Rules for borrowing:1. Any borrow must last for a scope no greater than that of the owner.

2. Only one of these kinds of borrows, but not both at the same time:• one or more references (&T) to a resource• exactly one mutable reference (&mut T)


letmutx=5;

lety=&mutx;*y+=1;

println!("{}",x);


ERROR cannot borrow `x` as immutable because it is also borrowed as mutable


Agenda

• Rust Overview

• Embedded Rust

• Cross Compiling

• MCU Debugging


Embedded Rust


zinc.rsZinc is an experimental attempt to write an ARM stack that would be similar to CMSIS or mbed in capabilities but would show rust’s best safety features applied to embedded development.

Zinc is mostly assembly-free and completely C-free at the moment.

http://zinc.rs


STM32 Nucleo-F411RE


STM32 Nucleo-F411RE

⬅

⬅

Demo



Agenda

• Rust Overview

• Embedded Rust

• Cross Compiling

• MCU Debugging


Cross-Compiling


Rustuphttps://www.rustup.rs/

rustup is an installer for the systems programming language Rust

> rustup install nightly-2016-09-17> cd zinc> rustup override set nightly-2016-09-17

https://www.rustup.rs/


GNU ARM Embedded Toolchainhttps://launchpad.net/gcc-arm-embedded/+download

arm-none-eabi-gccarm-none-eabi-gdb…

eabi = Embedded Application Binary Interface

https://launchpad.net/gcc-arm-embedded/+download


Building

cargo build --target=thumbv7em-none-eabi --features mcu_stm32f4

Demo



Agenda

• Rust Overview

• Embedded Rust

• Cross Compiling

• MCU Debugging


MCU Debugging


zinc.rs Issue #336 Failing to build example. #336

https://github.com/hackndev/zinc/issues/336#issuecomment-136204416


>openocd…-cgdb_port3333

>arm-none-eabi-gdb(gdb)targetremote:3333(gdb)file./target/thumbv7em-none-eabi/debug/blink_stm32f4(gdb)breakmain(gdb)continue(gdb)next(gdb)setdelay=1000(gdb)list(gdb)disassemble

Debugging

Demo



What we’ve seen

• Rust Overview ✔

• Embedded Rust ✔

• Cross Compiling ✔

• MCU Debugging ✔

• Hello World


What we’ve seen

• Rust Overview ✔

• Embedded Rust ✔

• Cross Compiling ✔

• MCU Debugging ✔

• blinking Hello World ✔


Thank you!

Embedded Rust – Rust on IoT devices

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