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Clean up some unsafe code introduced by #202 #253

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Clean up some unsafe code introduced by #202 #253

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39 changes: 14 additions & 25 deletions src/peripheral/scb.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -339,7 +339,9 @@ impl SCB {
// NOTE(unsafe): The asm routine manages exclusive access to the SCB
// registers and applies the proper barriers; it is technically safe on
// its own, and is only `unsafe` here because it's `extern "C"`.
unsafe { __enable_icache(); }
unsafe {
__enable_icache();
}
}

/// Disables I-cache if currently enabled.
Expand Down Expand Up @@ -412,7 +414,9 @@ impl SCB {
// NOTE(unsafe): The asm routine manages exclusive access to the SCB
// registers and applies the proper barriers; it is technically safe on
// its own, and is only `unsafe` here because it's `extern "C"`.
unsafe { __enable_dcache(); }
unsafe {
__enable_dcache();
}
}

/// Disables D-cache if currently enabled.
Expand Down Expand Up @@ -952,28 +956,19 @@ impl SCB {
/// [`NVIC.get_priority`](struct.NVIC.html#method.get_priority) for more details.
#[inline]
pub fn get_priority(system_handler: SystemHandler) -> u8 {
let index = system_handler as u8;
// TODO: Review it after rust-lang/rust/issues/13926 will be fixed.
let index = system_handler.clone() as u8;

#[cfg(not(armv6m))]
{
// NOTE(unsafe) atomic read with no side effects

// NOTE(unsafe): Index is bounded to [4,15] by SystemHandler design.
// TODO: Review it after rust-lang/rust/issues/13926 will be fixed.
let priority_ref = unsafe {(*Self::ptr()).shpr.get_unchecked(usize::from(index - 4))};

priority_ref.read()
unsafe { (*Self::ptr()).shpr[usize::from(index - 4)].read() }
}

#[cfg(armv6m)]
{
// NOTE(unsafe) atomic read with no side effects

// NOTE(unsafe): Index is bounded to [11,15] by SystemHandler design.
// TODO: Review it after rust-lang/rust/issues/13926 will be fixed.
let priority_ref = unsafe {(*Self::ptr()).shpr.get_unchecked(usize::from((index - 8) / 4))};

let shpr = priority_ref.read();
let shpr = unsafe { (*Self::ptr()).shpr[usize::from((index - 8) / 4)].read() };
let prio = (shpr >> (8 * (index % 4))) & 0x0000_00ff;
prio as u8
}
Expand All @@ -993,24 +988,18 @@ impl SCB {
/// [`register::basepri`](../register/basepri/index.html)) and compromise memory safety.
#[inline]
pub unsafe fn set_priority(&mut self, system_handler: SystemHandler, prio: u8) {
let index = system_handler as u8;
// TODO: Review it after rust-lang/rust/issues/13926 will be fixed.
let index = system_handler.clone() as u8;

#[cfg(not(armv6m))]
{
// NOTE(unsafe): Index is bounded to [4,15] by SystemHandler design.
// TODO: Review it after rust-lang/rust/issues/13926 will be fixed.
let priority_ref = (*Self::ptr()).shpr.get_unchecked(usize::from(index - 4));

priority_ref.write(prio)
self.shpr[usize::from(index - 4)].write(prio)
}

#[cfg(armv6m)]
{
// NOTE(unsafe): Index is bounded to [11,15] by SystemHandler design.
// TODO: Review it after rust-lang/rust/issues/13926 will be fixed.
let priority_ref = (*Self::ptr()).shpr.get_unchecked(usize::from((index - 8) / 4));

priority_ref.modify(|value| {
self.shpr[usize::from((index - 8) / 4)].modify(|value| {
let shift = 8 * (index % 4);
let mask = 0x0000_00ff << shift;
let prio = u32::from(prio) << shift;
Expand Down