Use critical section instead of interrupt::free

CHANGELOG.md

@@ -44,6 +44,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   implementation, but it is hard to maintain the current implementation
   and not easy to verify if it is really a safe implementation.
   It is also not consistent with the rest of the crates API. ([#352])
+- Use [critical-section] crate instead of `interrupt_free`, which is not always
+  sound. ([#350])
+
+[critical-section]: https://github.com/rust-embedded/critical-section
 
 ## [v0.9.2] - 2023-02-20
 
@@ -611,6 +615,7 @@ let clocks = rcc
 
 [#352]: https://github.com/stm32-rs/stm32f3xx-hal/pull/352
 [#351]: https://github.com/stm32-rs/stm32f3xx-hal/pull/351
+[#350]: https://github.com/stm32-rs/stm32f3xx-hal/pull/350
 [#345]: https://github.com/stm32-rs/stm32f3xx-hal/pull/345
 [#346]: https://github.com/stm32-rs/stm32f3xx-hal/pull/346
 [#347]: https://github.com/stm32-rs/stm32f3xx-hal/pull/347

Cargo.toml

@@ -31,6 +31,7 @@ bxcan = { version = "0.7.0", optional = true }
 cfg-if = "1.0.0"
 cortex-m = "0.7.4"
 cortex-m-rt = "0.7.3"
+critical-section = "1.1.2"
 defmt = { version = ">=0.2.3, <0.4.0", optional = true }
 embedded-dma = "0.2.0"
 embedded-hal = { version = "0.2.5", features = ["unproven"] }

examples/adc.rs

@@ -9,8 +9,8 @@ use panic_probe as _;
 use core::cell::RefCell;
 
 use cortex_m::asm;
-use cortex_m::interrupt::Mutex;
 use cortex_m_rt::entry;
+use critical_section::Mutex;
 
 use embedded_hal::adc::OneShot;
 use stm32f3xx_hal::{
@@ -99,7 +99,7 @@ fn main() -> ! {
     // Start a timer which fires regularly to wake up from `asm::wfi`
     timer.start(500.milliseconds());
     // Put the timer in the global context.
-    cortex_m::interrupt::free(|cs| {
+    critical_section::with(|cs| {
         TIMER.borrow(cs).replace(Some(timer));
     });
 
@@ -133,7 +133,7 @@ fn main() -> ! {
 #[interrupt]
 fn TIM2() {
     // Just handle the pending interrupt event.
-    cortex_m::interrupt::free(|cs| {
+    critical_section::with(|cs| {
         TIMER
             // Unlock resource for use in critical section
             .borrow(cs)

examples/gpio_interrupts.rs

@@ -5,8 +5,9 @@ use core::cell::RefCell;
 
 use panic_semihosting as _;
 
-use cortex_m::{asm, interrupt::Mutex, peripheral::NVIC};
+use cortex_m::{asm, peripheral::NVIC};
 use cortex_m_rt::entry;
+use critical_section::Mutex;
 
 use stm32f3xx_hal::{
     gpio::{self, Edge, Input, Output, PushPull},
@@ -38,7 +39,7 @@ fn main() -> ! {
     led.toggle().expect("unable to toggle led in configuration");
 
     // Move the ownership of the led to the global LED
-    cortex_m::interrupt::free(|cs| *LED.borrow(cs).borrow_mut() = Some(led));
+    critical_section::with(|cs| *LED.borrow(cs).borrow_mut() = Some(led));
 
     // Configuring the user button to trigger an interrupt when the button is pressed.
     let mut user_button = gpioa
@@ -50,7 +51,7 @@ fn main() -> ! {
     let interrupt_num = user_button.interrupt(); // hal::pac::Interrupt::EXTI0
 
     // Moving ownership to the global BUTTON so we can clear the interrupt pending bit.
-    cortex_m::interrupt::free(|cs| *BUTTON.borrow(cs).borrow_mut() = Some(user_button));
+    critical_section::with(|cs| *BUTTON.borrow(cs).borrow_mut() = Some(user_button));
 
     unsafe { NVIC::unmask(interrupt_num) };
 
@@ -67,7 +68,7 @@ fn main() -> ! {
 // This may be called more than once per button press from the user since the button may not be debounced.
 #[interrupt]
 fn EXTI0() {
-    cortex_m::interrupt::free(|cs| {
+    critical_section::with(|cs| {
         // Toggle the LED
         LED.borrow(cs)
             .borrow_mut()

src/adc.rs

@@ -133,7 +133,7 @@ where
 {
     /// Releases the common ADC peripheral
     pub fn free(self, _adcs: &<ADC as CommonInstance>::Childs) -> ADC {
-        cortex_m::interrupt::free(|_| {
+        critical_section::with(|_| {
             // SAFETY: Guaranteed to be the only instance left, which has control over the
             // `ADC`perpherals, and criticala section ensure that no race condition happens
             // on the `Bus` peripheral.

src/usb.rs

@@ -92,7 +92,9 @@ unsafe impl<Dm: DmPin + Send, Dp: DpPin + Send> UsbPeripheral for Peripheral<Dm,
     const EP_MEMORY_ACCESS_2X16: bool = true;
 
     fn enable() {
-        cortex_m::interrupt::free(|_| unsafe {
+        // SAFETY: the cricitcal section ensures, that the RCC access to enable the USB peripheral
+        // is mutually exclusive
+        critical_section::with(|_| unsafe {
             // Enable USB peripheral
             USB::enable_unchecked();
             // Reset USB peripheral