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MPU types no longer send #175

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MPU types no longer send #175

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1248a2e
Make EL1 and EL2 MPUs !Send
jonathanpallant Jun 8, 2026
112b42d
Make PMSAv7 MPU !Send
jonathanpallant Jun 8, 2026
d275071
Merge branch 'main' into mpu-no-longer-send
jonathanpallant Jun 25, 2026
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13 changes: 11 additions & 2 deletions aarch32-cpu/src/pmsav7.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@
//!
//! [armv7]: https://developer.arm.com/documentation/ddi0406/latest

use core::marker::PhantomData;

use crate::register;

use arbitrary_int::{u2, u3};
Expand All @@ -23,7 +25,12 @@ pub enum Error {
}

/// Represents our PMSAv7 MPU
pub struct Mpu();
///
/// This type is not [Send] because it is a per-core type and should not be moved across
/// cores on an SMP system.
pub struct Mpu {
_phantom: PhantomData<*const u8>,
}

impl Mpu {
/// Create an MPU handle
Expand All @@ -33,7 +40,9 @@ impl Mpu {
/// Only create one of these at any given time, as they access shared
/// mutable state within the processor and do read-modify-writes on that state.
pub unsafe fn new() -> Mpu {
Mpu()
Mpu {
_phantom: PhantomData,
}
}

/// How many MPU instruction regions are there?
Expand Down
26 changes: 22 additions & 4 deletions aarch32-cpu/src/pmsav8.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,8 @@
//!
//! [armv8r]: https://developer.arm.com/documentation/ddi0568/latest/

use core::marker::PhantomData;

use arbitrary_int::{u26, u3};

use crate::register;
Expand All @@ -28,7 +30,12 @@ pub enum Error {
}

/// Represents our PMSAv8-32 EL1 MPU
pub struct El1Mpu();
///
/// This type is not [Send] because it is a per-core type and should not be moved across
/// cores on an SMP system.
pub struct El1Mpu {
_phantom: PhantomData<*const u8>,
}

impl El1Mpu {
/// Create an MPU handle
Expand All @@ -38,7 +45,9 @@ impl El1Mpu {
/// Only create one of these at any given time, as they access shared
/// mutable state within the processor and do read-modify-writes on that state.
pub unsafe fn new() -> El1Mpu {
El1Mpu()
El1Mpu {
_phantom: PhantomData,
}
}

/// How many MPU regions are there?
Expand Down Expand Up @@ -199,7 +208,12 @@ impl El1Mpu {
}

/// Represents our PMSAv8-32 EL2 MPU
pub struct El2Mpu();
///
/// This type is not [Send] because it is a per-core type and should not be moved across
/// cores on an SMP system.
pub struct El2Mpu {
_phantom: PhantomData<*const u8>,
}

impl El2Mpu {
/// Create an EL2 MPU handle
Expand All @@ -209,7 +223,9 @@ impl El2Mpu {
/// Only create one of these at any given time, as they access shared
/// mutable state within the processor and do read-modify-writes on that state.
pub unsafe fn new() -> El2Mpu {
El2Mpu()
El2Mpu {
_phantom: PhantomData,
}
}

/// How many EL2 MPU regions are there?
Expand Down Expand Up @@ -407,6 +423,7 @@ pub struct El1Region {

// Creating a static Region is fine - the pointers within it
// only go to the MPU and aren't accessed via Rust code
unsafe impl Send for El1Region {}
unsafe impl Sync for El1Region {}

/// Configuration for the PMSAv8-32 EL2 MPU
Expand Down Expand Up @@ -454,6 +471,7 @@ pub struct El2Region {

// Creating a static El2Region is fine - the pointers within it
// only go to the MPU and aren't accessed via Rust code
unsafe impl Send for El2Region {}
unsafe impl Sync for El2Region {}

/// Describes the memory ordering and cacheability of a region
Expand Down
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