Replace interrupt::free with critical_section::with.

.github/workflows/ci.yml

@@ -29,6 +29,6 @@ jobs:
           toolchain: ${{ matrix.rust }}
           override: true
       - name: Run tests
-        run: cargo test --all --exclude cortex-m-rt --exclude testsuite
+        run: cargo test --all --exclude cortex-m-rt --exclude testsuite --features cortex-m/single-core-critical-section
 
 # FIXME: test on macOS and Windows

.github/workflows/clippy.yml

@@ -1,19 +1,14 @@
 on:
   push:
     branches: [ staging, trying, master ]
-  pull_request_target:
+  pull_request:
 
 name: Clippy check
 jobs:
   clippy:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-        if: github.event_name == 'pull_request_target'
-        with:
-          ref: refs/pull/${{ github.event.number }}/head
-      - uses: actions/checkout@v3
-        if: github.event_name != 'pull_request_target'
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
@@ -23,4 +18,4 @@ jobs:
       - uses: actions-rs/clippy-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
-          args: --all
+          args: --all --features cortex-m/single-core-critical-section

.github/workflows/rt-ci.yml

@@ -69,18 +69,18 @@ jobs:
       - name: Install all Rust targets
         run: rustup target install thumbv6m-none-eabi thumbv7m-none-eabi thumbv7em-none-eabi thumbv7em-none-eabihf thumbv8m.base-none-eabi thumbv8m.main-none-eabi thumbv8m.main-none-eabihf
       - name: Build examples for thumbv6m-none-eabi
-        run: cargo build --target=thumbv6m-none-eabi --examples
+        run: cargo build --target=thumbv6m-none-eabi --features cortex-m/single-core-critical-section --examples
       - name: Build examples for thumbv7m-none-eabi
-        run: cargo build --target=thumbv7m-none-eabi --examples
+        run: cargo build --target=thumbv7m-none-eabi --features cortex-m/single-core-critical-section --examples
       - name: Build examples for thumbv7em-none-eabi
-        run: cargo build --target=thumbv7em-none-eabi --examples
+        run: cargo build --target=thumbv7em-none-eabi --features cortex-m/single-core-critical-section --examples
       - name: Build examples for thumbv7em-none-eabihf
-        run: cargo build --target=thumbv7em-none-eabihf --examples
+        run: cargo build --target=thumbv7em-none-eabihf --features cortex-m/single-core-critical-section --examples
       - name: Build examples for thumbv8m.base-none-eabi
-        run: cargo build --target=thumbv8m.base-none-eabi --examples
+        run: cargo build --target=thumbv8m.base-none-eabi --features cortex-m/single-core-critical-section --examples
       - name: Build examples for thumbv8m.main-none-eabi
-        run: cargo build --target=thumbv8m.main-none-eabi --examples
+        run: cargo build --target=thumbv8m.main-none-eabi --features cortex-m/single-core-critical-section --examples
       - name: Build examples for thumbv8m.main-none-eabihf
-        run: cargo build --target=thumbv8m.main-none-eabihf --examples
+        run: cargo build --target=thumbv8m.main-none-eabihf --features cortex-m/single-core-critical-section --examples
       - name: Build crate for host OS
         run: cargo build

cortex-m-rt/ci/script.sh

@@ -7,10 +7,13 @@ main() {
 
     cargo check --target "$TARGET" --features device
 
+    # A `critical_section` implementation is always needed.
+    needed_features=cortex-m/single-core-critical-section
+
     if [ "$TARGET" = x86_64-unknown-linux-gnu ] && [ "$TRAVIS_RUST_VERSION" = stable ]; then
         ( cd macros && cargo check && cargo test )
 
-        cargo test --features device --test compiletest
+        cargo test --features "device,${needed_features}" --test compiletest
     fi
 
     local examples=(
@@ -43,35 +46,35 @@ main() {
     if [ "$TARGET" != x86_64-unknown-linux-gnu ]; then
         # Only test on stable and nightly, not MSRV.
         if [ "$TRAVIS_RUST_VERSION" = stable ] || [ "$TRAVIS_RUST_VERSION" = nightly ]; then
-            RUSTDOCFLAGS="-Cpanic=abort" cargo test --doc
+            RUSTDOCFLAGS="-Cpanic=abort" cargo test --features "${needed_features}" --doc
         fi
 
         for linker in "${linkers[@]}"; do
             for ex in "${examples[@]}"; do
-                cargo rustc --target "$TARGET" --example "$ex" -- $linker
-                cargo rustc --target "$TARGET" --example "$ex" --release -- $linker
+                cargo rustc --target "$TARGET" --example "$ex" --features "${needed_features}" -- $linker
+                cargo rustc --target "$TARGET" --example "$ex" --features "${needed_features}" --release -- $linker
             done
             for ex in "${fail_examples[@]}"; do
-                ! cargo rustc --target "$TARGET" --example "$ex" -- $linker
-                ! cargo rustc --target "$TARGET" --example "$ex" --release -- $linker
+                ! cargo rustc --target "$TARGET" --example "$ex" --features "${needed_features}" -- $linker
+                ! cargo rustc --target "$TARGET" --example "$ex" --features "${needed_features}" --release -- $linker
             done
-            cargo rustc --target "$TARGET" --example device --features device -- $linker
-            cargo rustc --target "$TARGET" --example device --features device --release -- $linker
+            cargo rustc --target "$TARGET" --example device --features "device,${needed_features}" -- $linker
+            cargo rustc --target "$TARGET" --example device --features "device,${needed_features}" --release -- $linker
 
-            cargo rustc --target "$TARGET" --example minimal --features set-sp -- $linker
-            cargo rustc --target "$TARGET" --example minimal --features set-sp --release -- $linker
-            cargo rustc --target "$TARGET" --example minimal --features set-vtor -- $linker
-            cargo rustc --target "$TARGET" --example minimal --features set-vtor --release -- $linker
+            cargo rustc --target "$TARGET" --example minimal --features "set-sp,${needed_features}" -- $linker
+            cargo rustc --target "$TARGET" --example minimal --features "set-sp,${needed_features}" --release -- $linker
+            cargo rustc --target "$TARGET" --example minimal --features "set-vtor,${needed_features}" -- $linker
+            cargo rustc --target "$TARGET" --example minimal --features "set-vtor,${needed_features}" --release -- $linker
         done
     fi
 
     case $TARGET in
         thumbv6m-none-eabi|thumbv7m-none-eabi)
             for linker in "${linkers[@]}"; do
                 env RUSTFLAGS="$linker -C link-arg=-Tlink.x" cargo run \
-                    --target "$TARGET" --example qemu | grep "x = 42"
+                    --target "$TARGET" --features "${needed_features}" --example qemu | grep "x = 42"
                 env RUSTFLAGS="$linker -C link-arg=-Tlink.x" cargo run \
-                    --target "$TARGET" --example qemu --release | grep "x = 42"
+                    --target "$TARGET" --features "${needed_features}" --example qemu --release | grep "x = 42"
             done
 
             ;;

cortex-m-semihosting/Cargo.toml

@@ -21,3 +21,4 @@ no-semihosting = []
 
 [dependencies]
 cortex-m = { path = "..", version = ">= 0.5.8, < 0.8" }
+critical-section = "0.2"

cortex-m-semihosting/src/export.rs

@@ -2,14 +2,12 @@
 
 use core::fmt::{self, Write};
 
-use cortex_m::interrupt;
-
 use crate::hio::{self, HostStream};
 
 static mut HSTDOUT: Option<HostStream> = None;
 
 pub fn hstdout_str(s: &str) {
-    let _result = interrupt::free(|| unsafe {
+    let _result = critical_section::with(|_| unsafe {
         if HSTDOUT.is_none() {
             HSTDOUT = Some(hio::hstdout()?);
         }
@@ -19,7 +17,7 @@ pub fn hstdout_str(s: &str) {
 }
 
 pub fn hstdout_fmt(args: fmt::Arguments) {
-    let _result = interrupt::free(|| unsafe {
+    let _result = critical_section::with(|_| unsafe {
         if HSTDOUT.is_none() {
             HSTDOUT = Some(hio::hstdout()?);
         }
@@ -31,7 +29,7 @@ pub fn hstdout_fmt(args: fmt::Arguments) {
 static mut HSTDERR: Option<HostStream> = None;
 
 pub fn hstderr_str(s: &str) {
-    let _result = interrupt::free(|| unsafe {
+    let _result = critical_section::with(|_| unsafe {
         if HSTDERR.is_none() {
             HSTDERR = Some(hio::hstderr()?);
         }
@@ -41,7 +39,7 @@ pub fn hstderr_str(s: &str) {
 }
 
 pub fn hstderr_fmt(args: fmt::Arguments) {
-    let _result = interrupt::free(|| unsafe {
+    let _result = critical_section::with(|_| unsafe {
         if HSTDERR.is_none() {
             HSTDERR = Some(hio::hstderr()?);
         }

src/critical_section.rs

@@ -1,27 +1,32 @@
-use crate::interrupt;
-use crate::register::primask::{self, Primask};
+#[cfg(all(cortex_m, feature = "single-core-critical-section"))]
+mod single_core_critical_section {
+    use crate::interrupt;
+    use crate::register::primask::{self, Primask};
 
-struct CriticalSection;
-critical_section::custom_impl!(CriticalSection);
+    struct CriticalSection;
+    critical_section::custom_impl!(CriticalSection);
 
-const TOKEN_IGNORE: u8 = 0;
-const TOKEN_REENABLE: u8 = 1;
+    const TOKEN_IGNORE: u8 = 0;
+    const TOKEN_REENABLE: u8 = 1;
 
-unsafe impl critical_section::Impl for CriticalSection {
-    unsafe fn acquire() -> u8 {
-        match primask::read() {
-            Primask::Active => {
-                interrupt::disable();
-                TOKEN_REENABLE
+    unsafe impl critical_section::Impl for CriticalSection {
+        unsafe fn acquire() -> u8 {
+            match primask::read() {
+                Primask::Active => {
+                    interrupt::disable();
+                    TOKEN_REENABLE
+                }
+                Primask::Inactive => TOKEN_IGNORE,
             }
-            Primask::Inactive => TOKEN_IGNORE,
         }
-    }
 
-    unsafe fn release(token: u8) {
-        // Only re-enable interrupts if they were enabled before the critical section.
-        if token == TOKEN_REENABLE {
-            interrupt::enable()
+        unsafe fn release(token: u8) {
+            // Only re-enable interrupts if they were enabled before the critical section.
+            if token == TOKEN_REENABLE {
+                interrupt::enable()
+            }
         }
     }
 }
+
+pub use critical_section::with;

src/lib.rs

@@ -49,8 +49,11 @@ mod macros;
 pub mod asm;
 #[cfg(armv8m)]
 pub mod cmse;
-#[cfg(all(cortex_m, feature = "single-core-critical-section"))]
-mod critical_section;
+// This is only public so the `singleton` macro does not require depending on
+// the `critical-section` crate separately.
+#[doc(hidden)]
+#[cfg(feature = "critical-section")]
+pub mod critical_section;
 pub mod delay;
 pub mod interrupt;
 #[cfg(all(not(armv6m), not(armv8m_base)))]

src/macros.rs

@@ -62,7 +62,7 @@ macro_rules! iprintln {
 #[macro_export]
 macro_rules! singleton {
     ($name:ident: $ty:ty = $expr:expr) => {
-        $crate::interrupt::free(|| {
+        $crate::critical_section::with(|_| {
             // this is a tuple of a MaybeUninit and a bool because using an Option here is
             // problematic:  Due to niche-optimization, an Option could end up producing a non-zero
             // initializer value which would move the entire static from `.bss` into `.data`...

src/peripheral/mod.rs

@@ -57,7 +57,6 @@
 //!
 //! - ARMv7-M Architecture Reference Manual (Issue E.b) - Chapter B3
 
-use crate::interrupt;
 use core::marker::PhantomData;
 use core::ops;
 
@@ -164,7 +163,7 @@ impl Peripherals {
     /// Returns all the core peripherals *once*
     #[inline]
     pub fn take() -> Option<Self> {
-        interrupt::free(|| {
+        critical_section::with(|_| {
             if unsafe { TAKEN } {
                 None
             } else {

src/peripheral/sau.rs

@@ -7,7 +7,6 @@
 //!
 //! For reference please check the section B8.3 of the Armv8-M Architecture Reference Manual.
 
-use crate::interrupt;
 use crate::peripheral::SAU;
 use bitfield::bitfield;
 use volatile_register::{RO, RW};
@@ -162,7 +161,7 @@ impl SAU {
     /// This function is executed under a critical section to prevent having inconsistent results.
     #[inline]
     pub fn set_region(&mut self, region_number: u8, region: SauRegion) -> Result<(), SauError> {
-        interrupt::free(|| {
+        critical_section::with(|_| {
             let base_address = region.base_address;
             let limit_address = region.limit_address;
             let attribute = region.attribute;
@@ -215,7 +214,7 @@ impl SAU {
     /// This function is executed under a critical section to prevent having inconsistent results.
     #[inline]
     pub fn get_region(&mut self, region_number: u8) -> Result<SauRegion, SauError> {
-        interrupt::free(|| {
+        critical_section::with(|_| {
             if region_number >= self.region_numbers() {
                 Err(SauError::RegionNumberTooBig)
             } else {

xtask/tests/ci.rs

@@ -32,6 +32,13 @@ fn build(package: &str, target: &str, features: &[&str]) {
         cargo.args(&["--features", *feat]);
     }
 
+    // A `critical_section` implementation is always needed.
+    if package == "cortex-m" {
+        cargo.args(&["--features", "single-core-critical-section"]);
+    } else {
+        cargo.args(&["--features", "cortex-m/single-core-critical-section"]);
+    }
+
     // Cargo features don't work right when invoked from the workspace root, so change to the
     // package's directory when necessary.
     if package != "cortex-m" {