在ST Nucleo-L152RE上使用rtt-target crate编译失败求助

问题描述 #

我在针对ST Nucleo-L152RE的Rust嵌入式项目中引入rtt-target crate，添加rtt_init_print!()和rprintln!()语句后，执行cargo build时编译失败，出现链接错误。相关文件及错误信息如下：

Cargo.toml #

# Cargo.toml
[package]
edition = "2018"
name = "blinky-rust"
version = "0.1.0"

[profile.release]
opt-level = 'z' # turn on maximum optimizations. We only have 64kB
lto = true      # Link-time-optimizations for further size reduction

[dependencies]
cortex-m = "^0.6.3"      # Access to the generic ARM peripherals
cortex-m-rt = "^0.6.12"  # Startup code for the ARM Core
embedded-hal = "^0.2.4"  # Access to generic embedded functions (`set_high`)
panic-halt = "^0.2.0"    # Panic handler
rtt-target = "0.5.0"

# Access to the HAL.
[dependencies.stm32l1xx-hal]
features = ["stm32l151", "rt"]
version = "^0.0.1"

main.rs #

# main.rs
#![no_main]
#![no_std]

use panic_halt as _;

use cortex_m_rt::entry;
use stm32l1xx_hal::delay::Delay;
use stm32l1xx_hal::gpio::GpioExt;
use stm32l1xx_hal::hal::digital::v2::OutputPin;
use stm32l1xx_hal::rcc::{Config, RccExt};
use stm32l1xx_hal::stm32::Peripherals;
use stm32l1xx_hal::stm32::CorePeripherals;
use stm32l1xx_hal::time::MicroSeconds;

use rtt_target::{rtt_init_print, rprintln};

#[entry]
fn main() -> ! {
    rtt_init_print!();

    let p = Peripherals::take().unwrap();
    let cp = CorePeripherals::take().unwrap();

    // Get LED pin PB6
    let gpioa = p.GPIOA.split();
    let mut led = gpioa.pa5.into_push_pull_output();

    // Set up a delay
    let rcc = p.RCC.freeze(Config::default());
    let mut delay = Delay::new(cp.SYST, rcc.clocks);

    loop {
        rprintln!("Hello, world!"); 

        // Turn LED On
        led.set_high().unwrap();

        delay.delay(MicroSeconds(2_000_000_u32));

        // Turn LED Off
        led.set_low().unwrap();

        delay.delay(MicroSeconds(1_000_000_u32));
    }
}

Embed.toml #

# Embed.toml

[default.general]
chip = "STM32L152RE"

[default.rtt]
enabled = true

[default.probe]
protocol = "Swd"

[default.gdb]
enabled = false

编译错误信息 #

Compiling blinky-rust v0.1.0 (/home/alex/projects/cortex-m-quickstart)
error: linking with `arm-none-eabi-ld` failed: exit status: 1
     = note: arm-none-eabi-ld: /home/alex/projects/cortex-m-quickstart/target/thumbv7m-none-eabi/debug/deps/librtt_target-df1e3f299aa0549b.rlib(rtt_target-df1e3f299aa0549b.rtt_target.1a0c5dea5ce969ca-cgu.0.rcgu.o): in function `critical_section::acquire':
          /home/alex/.cargo/registry/src/index.crates.io-6f17d22bba15001f/critical-section-1.1.2/src/lib.rs:183: undefined reference to `_critical_section_1_0_acquire'
          arm-none-eabi-ld: /home/alex/.cargo/registry/src/index.crates.io-6f17d22bba15001f/critical-section-1.1.2/src/lib.rs:183: undefined reference to `_critical_section_1_0_acquire'
          arm-none-eabi-ld: /home/alex/projects/cortex-m-quickstart/target/thumbv7m-none-eabi/debug/deps/librtt_target-df1e3f299aa0549b.rlib(rtt_target-df1e3f299aa0549b.rtt_target.1a0c5dea5ce969ca-cgu.0.rcgu.o): in function `critical_section::release':
          /home/alex/.cargo/registry/src/index.crates.io-6f17d22bba15001f/critical-section-1.1.2/src/lib.rs:200: undefined reference to `_critical_section_1_0_release'

  = note: some `extern` functions couldn't be found; some native libraries may need to be installed or have their path specified
  = note: use the `-l` flag to specify native libraries to link
  = note: use the `cargo:rustc-link-lib` directive to specify the native libraries to link with Cargo (see https://doc.rust-lang.org/cargo/reference/build-scripts.html#cargorustc-link-libkindname)

error: could not compile `blinky-rust` (bin "blinky-rust") due to previous error

解决方案 #

错误原因 #

链接错误提示找不到_critical_section_1_0_acquire和_critical_section_1_0_release符号，这是因为rtt-target v0.5.0依赖critical-section crate，但当前项目没有提供该crate的具体实现——在旧版Cortex-M Rust生态中，critical-section的实现需要显式引入。

修复步骤 #

• 添加critical-section实现依赖
  在Cargo.toml的[dependencies]区块中添加以下内容：

critical-section = "1.1.2"
critical-section-cortex-m = "1.1.2"

• 启用critical-section实现
  在main.rs的开头（use panic_halt as _;之后）添加一行代码，确保实现被链接到项目：

use critical_section_cortex_m as _;

• 可选：升级依赖版本（推荐）
  当前项目使用的stm32l1xx-hal版本^0.0.1过于老旧，建议升级到稳定版本（如0.15.0），同时同步更新其他依赖以保证兼容性：

[dependencies]
cortex-m = "0.7.7"
cortex-m-rt = "0.7.3"
embedded-hal = "0.2.7"
panic-halt = "0.2.0"
rtt-target = "0.5.0"
critical-section = "1.1.2"
critical-section-cortex-m = "1.1.2"

[dependencies.stm32l1xx-hal]
features = ["stm32l152re", "rt"]
version = "0.15.0"

注意：升级HAL版本后，可能需要调整main.rs中的部分API调用（比如Delay初始化、GPIO拆分逻辑），具体参考对应版本的HAL文档。

• 重新编译
  执行cargo build，此时链接错误应被修复，之后即可通过RTT工具查看设备日志。

内容的提问来源于stack exchange，提问作者Oleksandr