Bump toolchain to 2024-09-17

This commit contains some code changes that have to be made atomically
with the toolchain, to avoid angering our warnings check in the build:

- Removed now-stable asm_const feature
- Fixed some addr_of instances that are now safe (woo!)

Cargo.toml

@@ -76,7 +76,7 @@ memoffset = { version = "0.6.5", default-features = false }
 multimap = { version = "0.8.3", default-features = false }
 nb = { version = "1", default-features = false }
 num = { version = "0.4", default-features = false }
-num-derive = { version = "0.3.3", default-features = false, features = ["full-syntax"] }
+num-derive = { version = "0.4", default-features = false }
 num-traits = { version = "0.2.12", default-features = false }
 p256 = { version = "0.13.2", default-features = false, features = ["ecdsa"] }
 panic-halt = { version = "0.2.0", default-features = false }

lib/lpc55-rot-startup/src/images.rs

@@ -173,7 +173,7 @@ impl Image {
     ) -> Result<Image, ImageError> {
         // Make sure we can access the page where the vectors live.
         // Safety: Link time constants from our own image.
-        let vector_size = unsafe { core::ptr::addr_of!(__vector_size) as u32 };
+        let vector_size = core::ptr::addr_of!(__vector_size) as u32;
         if !slot.is_span_programmed(slot.start(), vector_size) {
             return Err(ImageError::FirstPageErased);
         }
@@ -248,11 +248,7 @@ impl Image {
     // Note that it may not be present if the image
     // is corrupted or is a bootloader.
     fn get_header_ptr(&self) -> *const ImageHeader {
-        // Safety: This is generated by the linker script which we trust
-        // Note that this is generated from _this_ image's linker script
-        // as opposed to the _image_ linker script but those two _must_
-        // be the same value!
-        let vector_size = unsafe { core::ptr::addr_of!(__vector_size) as u32 };
+        let vector_size = core::ptr::addr_of!(__vector_size) as u32;
         (self.get_img_start() + vector_size) as *const ImageHeader
     }
 

rust-toolchain.toml

@@ -1,5 +1,5 @@
 [toolchain]
-channel = "nightly-2024-04-04"
+channel = "nightly-2024-09-17"
 targets = [ "thumbv6m-none-eabi", "thumbv7em-none-eabihf", "thumbv8m.main-none-eabihf" ]
 profile = "minimal"
 components = [ "rustfmt" ]

sys/kern/src/lib.rs

@@ -28,7 +28,6 @@
 
 #![cfg_attr(target_os = "none", no_std)]
 #![feature(naked_functions)]
-#![feature(asm_const)]
 // Require an unsafe block even in an unsafe fn, because unsafe fns are about
 // contract, not implementation.
 #![forbid(unsafe_op_in_unsafe_fn)]

sys/kern/src/startup.rs

@@ -101,11 +101,8 @@ pub(crate) fn with_task_table<R>(body: impl FnOnce(&mut [Task]) -> R) -> R {
     if TASK_TABLE_IN_USE.swap_polyfill(true, Ordering::Acquire) {
         panic!(); // recursive use of with_task_table
     }
-    // Safety: tbh it's never been clear to me why addr_of_mut is unsafe when it
-    // produces a raw pointer, but, see the Safety justification on the
-    // derefrence below for the full argument on why we can do this.
     let task_table: *mut MaybeUninit<[Task; HUBRIS_TASK_COUNT]> =
-        unsafe { core::ptr::addr_of_mut!(HUBRIS_TASK_TABLE_SPACE) };
+        core::ptr::addr_of_mut!(HUBRIS_TASK_TABLE_SPACE);
     // Pointer cast valid as MaybeUninit<[T; N]> and [MaybeUninit<T>; N] have
     // same in-memory representation. At the time of this writing
     // MaybeUninit::transpose is not yet stable.

sys/userlib/src/lib.rs

@@ -25,7 +25,6 @@
 //! See: https://github.com/rust-lang/rust/issues/73450#issuecomment-650463347
 
 #![no_std]
-#![feature(asm_const)]
 #![feature(naked_functions)]
 #![forbid(clippy::wildcard_imports)]