Replace interrupt::free with critical_section::with.

Author: reitermarkus

.github/workflows/clippy.yml

@@ -23,4 +23,4 @@ jobs:
       - uses: actions-rs/clippy-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
-          args: --all
+          args: --all --features single-core-critical-section

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

@@ -162,7 +162,7 @@ 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 +215,7 @@ 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 {