From e65e532c2a342f77080ac6fc8e5be11aa7d82575 Mon Sep 17 00:00:00 2001 From: Emil Fresk Date: Sun, 29 Jan 2023 20:16:23 +0100 Subject: Move common data structures to `rtic-common` --- rtic-common/.gitignore | 2 + rtic-common/CHANGELOG.md | 16 ++ rtic-common/Cargo.toml | 13 ++ rtic-common/src/lib.rs | 8 + rtic-common/src/wait_queue.rs | 271 ++++++++++++++++++++++++++++++++++ rtic-common/src/waker_registration.rs | 66 +++++++++ 6 files changed, 376 insertions(+) create mode 100644 rtic-common/.gitignore create mode 100644 rtic-common/CHANGELOG.md create mode 100644 rtic-common/Cargo.toml create mode 100644 rtic-common/src/lib.rs create mode 100644 rtic-common/src/wait_queue.rs create mode 100644 rtic-common/src/waker_registration.rs (limited to 'rtic-common') diff --git a/rtic-common/.gitignore b/rtic-common/.gitignore new file mode 100644 index 0000000..1e7caa9 --- /dev/null +++ b/rtic-common/.gitignore @@ -0,0 +1,2 @@ +Cargo.lock +target/ diff --git a/rtic-common/CHANGELOG.md b/rtic-common/CHANGELOG.md new file mode 100644 index 0000000..d3a9d84 --- /dev/null +++ b/rtic-common/CHANGELOG.md @@ -0,0 +1,16 @@ +# Change Log + +All notable changes to this project will be documented in this file. +This project adheres to [Semantic Versioning](http://semver.org/). + +For each category, *Added*, *Changed*, *Fixed* add new entries at the top! + +## [Unreleased] + +### Added + +### Changed + +### Fixed + +## [v1.0.0] - 2023-xx-xx diff --git a/rtic-common/Cargo.toml b/rtic-common/Cargo.toml new file mode 100644 index 0000000..258caae --- /dev/null +++ b/rtic-common/Cargo.toml @@ -0,0 +1,13 @@ +[package] +name = "rtic-common" +version = "1.0.0" +edition = "2021" + +# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html + +[dependencies] +critical-section = "1" + +[features] +default = [] +testing = ["critical-section/std"] diff --git a/rtic-common/src/lib.rs b/rtic-common/src/lib.rs new file mode 100644 index 0000000..3c75856 --- /dev/null +++ b/rtic-common/src/lib.rs @@ -0,0 +1,8 @@ +//! Crate + +#![no_std] +#![deny(missing_docs)] +//deny_warnings_placeholder_for_ci + +pub mod wait_queue; +pub mod waker_registration; diff --git a/rtic-common/src/wait_queue.rs b/rtic-common/src/wait_queue.rs new file mode 100644 index 0000000..ba8ff54 --- /dev/null +++ b/rtic-common/src/wait_queue.rs @@ -0,0 +1,271 @@ +//! ... + +use core::marker::PhantomPinned; +use core::pin::Pin; +use core::ptr::null_mut; +use core::sync::atomic::{AtomicBool, AtomicPtr, Ordering}; +use core::task::Waker; +use critical_section as cs; + +/// A helper definition of a wait queue. +pub type WaitQueue = LinkedList; + +/// A FIFO linked list for a wait queue. +pub struct LinkedList { + head: AtomicPtr>, // UnsafeCell<*mut Link> + tail: AtomicPtr>, +} + +impl LinkedList { + /// Create a new linked list. + pub const fn new() -> Self { + Self { + head: AtomicPtr::new(null_mut()), + tail: AtomicPtr::new(null_mut()), + } + } +} + +impl LinkedList { + const R: Ordering = Ordering::Relaxed; + + /// Pop the first element in the queue. + pub fn pop(&self) -> Option { + cs::with(|_| { + // Make sure all previous writes are visible + core::sync::atomic::fence(Ordering::SeqCst); + + let head = self.head.load(Self::R); + + // SAFETY: `as_ref` is safe as `insert` requires a valid reference to a link + if let Some(head_ref) = unsafe { head.as_ref() } { + // Move head to the next element + self.head.store(head_ref.next.load(Self::R), Self::R); + + // We read the value at head + let head_val = head_ref.val.clone(); + + let tail = self.tail.load(Self::R); + if head == tail { + // The queue is empty + self.tail.store(null_mut(), Self::R); + } + + if let Some(next_ref) = unsafe { head_ref.next.load(Self::R).as_ref() } { + next_ref.prev.store(null_mut(), Self::R); + } + + // Clear the pointers in the node. + head_ref.next.store(null_mut(), Self::R); + head_ref.prev.store(null_mut(), Self::R); + head_ref.is_poped.store(true, Self::R); + + return Some(head_val); + } + + None + }) + } + + /// Put an element at the back of the queue. + pub fn push(&self, link: Pin<&mut Link>) { + cs::with(|_| { + // Make sure all previous writes are visible + core::sync::atomic::fence(Ordering::SeqCst); + + let tail = self.tail.load(Self::R); + + // SAFETY: This datastructure does not move the underlying value. + let link = unsafe { link.get_unchecked_mut() }; + + if let Some(tail_ref) = unsafe { tail.as_ref() } { + // Queue is not empty + link.prev.store(tail, Self::R); + self.tail.store(link, Self::R); + tail_ref.next.store(link, Self::R); + } else { + // Queue is empty + self.tail.store(link, Self::R); + self.head.store(link, Self::R); + } + }); + } + + /// Check if the queue is empty. + pub fn is_empty(&self) -> bool { + self.head.load(Self::R).is_null() + } +} + +/// A link in the linked list. +pub struct Link { + pub(crate) val: T, + next: AtomicPtr>, + prev: AtomicPtr>, + is_poped: AtomicBool, + _up: PhantomPinned, +} + +impl Link { + const R: Ordering = Ordering::Relaxed; + + /// Create a new link. + pub const fn new(val: T) -> Self { + Self { + val, + next: AtomicPtr::new(null_mut()), + prev: AtomicPtr::new(null_mut()), + is_poped: AtomicBool::new(false), + _up: PhantomPinned, + } + } + + /// Return true if this link has been poped from the list. + pub fn is_poped(&self) -> bool { + self.is_poped.load(Self::R) + } + + /// Remove this link from a linked list. + pub fn remove_from_list(&mut self, list: &LinkedList) { + cs::with(|_| { + // Make sure all previous writes are visible + core::sync::atomic::fence(Ordering::SeqCst); + + let prev = self.prev.load(Self::R); + let next = self.next.load(Self::R); + self.is_poped.store(true, Self::R); + + match unsafe { (prev.as_ref(), next.as_ref()) } { + (None, None) => { + // Not in the list or alone in the list, check if list head == node address + let sp = self as *const _; + + if sp == list.head.load(Ordering::Relaxed) { + list.head.store(null_mut(), Self::R); + list.tail.store(null_mut(), Self::R); + } + } + (None, Some(next_ref)) => { + // First in the list + next_ref.prev.store(null_mut(), Self::R); + list.head.store(next, Self::R); + } + (Some(prev_ref), None) => { + // Last in the list + prev_ref.next.store(null_mut(), Self::R); + list.tail.store(prev, Self::R); + } + (Some(prev_ref), Some(next_ref)) => { + // Somewhere in the list + + // Connect the `prev.next` and `next.prev` with each other to remove the node + prev_ref.next.store(next, Self::R); + next_ref.prev.store(prev, Self::R); + } + } + }) + } +} + +#[cfg(test)] +impl LinkedList { + fn print(&self) { + cs::with(|_| { + // Make sure all previous writes are visible + core::sync::atomic::fence(Ordering::SeqCst); + + let mut head = self.head.load(Self::R); + let tail = self.tail.load(Self::R); + + println!( + "List - h = 0x{:x}, t = 0x{:x}", + head as usize, tail as usize + ); + + let mut i = 0; + + // SAFETY: `as_ref` is safe as `insert` requires a valid reference to a link + while let Some(head_ref) = unsafe { head.as_ref() } { + println!( + " {}: {:?}, s = 0x{:x}, n = 0x{:x}, p = 0x{:x}", + i, + head_ref.val, + head as usize, + head_ref.next.load(Ordering::Relaxed) as usize, + head_ref.prev.load(Ordering::Relaxed) as usize + ); + + head = head_ref.next.load(Self::R); + + i += 1; + } + }); + } +} + +#[cfg(test)] +impl Link { + fn print(&self) { + cs::with(|_| { + // Make sure all previous writes are visible + core::sync::atomic::fence(Ordering::SeqCst); + + println!("Link:"); + + println!( + " val = {:?}, n = 0x{:x}, p = 0x{:x}", + self.val, + self.next.load(Ordering::Relaxed) as usize, + self.prev.load(Ordering::Relaxed) as usize + ); + }); + } +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn linked_list() { + let wq = LinkedList::::new(); + + let mut i1 = Link::new(10); + let mut i2 = Link::new(11); + let mut i3 = Link::new(12); + let mut i4 = Link::new(13); + let mut i5 = Link::new(14); + + wq.push(unsafe { Pin::new_unchecked(&mut i1) }); + wq.push(unsafe { Pin::new_unchecked(&mut i2) }); + wq.push(unsafe { Pin::new_unchecked(&mut i3) }); + wq.push(unsafe { Pin::new_unchecked(&mut i4) }); + wq.push(unsafe { Pin::new_unchecked(&mut i5) }); + + wq.print(); + + wq.pop(); + i1.print(); + + wq.print(); + + i4.remove_from_list(&wq); + + wq.print(); + + // i1.remove_from_list(&wq); + // wq.print(); + + println!("i2"); + i2.remove_from_list(&wq); + wq.print(); + + println!("i3"); + i3.remove_from_list(&wq); + wq.print(); + + println!("i5"); + i5.remove_from_list(&wq); + wq.print(); + } +} diff --git a/rtic-common/src/waker_registration.rs b/rtic-common/src/waker_registration.rs new file mode 100644 index 0000000..174765c --- /dev/null +++ b/rtic-common/src/waker_registration.rs @@ -0,0 +1,66 @@ +//! Waker registration utility. + +use core::cell::UnsafeCell; +use core::task::Waker; + +/// A critical section based waker handler. +pub struct CriticalSectionWakerRegistration { + waker: UnsafeCell>, +} + +unsafe impl Send for CriticalSectionWakerRegistration {} +unsafe impl Sync for CriticalSectionWakerRegistration {} + +impl CriticalSectionWakerRegistration { + /// Create a new waker registration. + pub const fn new() -> Self { + Self { + waker: UnsafeCell::new(None), + } + } + + /// Register a waker. + /// This will overwrite the previous waker if there was one. + pub fn register(&self, new_waker: &Waker) { + critical_section::with(|_| { + // SAFETY: This access is protected by the critical section. + let self_waker = unsafe { &mut *self.waker.get() }; + + // From embassy + // https://github.com/embassy-rs/embassy/blob/b99533607ceed225dd12ae73aaa9a0d969a7365e/embassy-sync/src/waitqueue/waker.rs#L59-L61 + match self_waker { + // Optimization: If both the old and new Wakers wake the same task, we can simply + // keep the old waker, skipping the clone. (In most executor implementations, + // cloning a waker is somewhat expensive, comparable to cloning an Arc). + Some(ref w2) if (w2.will_wake(new_waker)) => {} + _ => { + // clone the new waker and store it + if let Some(old_waker) = core::mem::replace(self_waker, Some(new_waker.clone())) + { + // We had a waker registered for another task. Wake it, so the other task can + // reregister itself if it's still interested. + // + // If two tasks are waiting on the same thing concurrently, this will cause them + // to wake each other in a loop fighting over this WakerRegistration. This wastes + // CPU but things will still work. + // + // If the user wants to have two tasks waiting on the same thing they should use + // a more appropriate primitive that can store multiple wakers. + old_waker.wake() + } + } + } + }); + } + + /// Wake the waker. + pub fn wake(&self) { + critical_section::with(|_| { + // SAFETY: This access is protected by the critical section. + let self_waker = unsafe { &mut *self.waker.get() }; + if let Some(waker) = self_waker.take() { + waker.wake() + } + }); + } +} -- cgit v1.2.3 From 5c1cefbf4e249c38467e3f6eb4e061e5b8073d6c Mon Sep 17 00:00:00 2001 From: Emil Fresk Date: Mon, 30 Jan 2023 14:49:24 +0100 Subject: Add `rtic-arbiter` --- rtic-common/src/dropper.rs | 26 ++++++++++++++++++++++++++ rtic-common/src/lib.rs | 1 + 2 files changed, 27 insertions(+) create mode 100644 rtic-common/src/dropper.rs (limited to 'rtic-common') diff --git a/rtic-common/src/dropper.rs b/rtic-common/src/dropper.rs new file mode 100644 index 0000000..a4b4d15 --- /dev/null +++ b/rtic-common/src/dropper.rs @@ -0,0 +1,26 @@ +//! A drop implementation runner. + +/// Runs a closure on drop. +pub struct OnDrop { + f: core::mem::MaybeUninit, +} + +impl OnDrop { + /// Make a new droppper given a closure. + pub fn new(f: F) -> Self { + Self { + f: core::mem::MaybeUninit::new(f), + } + } + + /// Make it not run drop. + pub fn defuse(self) { + core::mem::forget(self) + } +} + +impl Drop for OnDrop { + fn drop(&mut self) { + unsafe { self.f.as_ptr().read()() } + } +} diff --git a/rtic-common/src/lib.rs b/rtic-common/src/lib.rs index 3c75856..b8b5e0d 100644 --- a/rtic-common/src/lib.rs +++ b/rtic-common/src/lib.rs @@ -4,5 +4,6 @@ #![deny(missing_docs)] //deny_warnings_placeholder_for_ci +pub mod dropper; pub mod wait_queue; pub mod waker_registration; -- cgit v1.2.3 From 15d788b7fad0254ad3323962b8dd6753cf95796d Mon Sep 17 00:00:00 2001 From: Emil Fresk Date: Tue, 31 Jan 2023 15:55:14 +0100 Subject: Fix spelling error --- rtic-common/src/wait_queue.rs | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'rtic-common') diff --git a/rtic-common/src/wait_queue.rs b/rtic-common/src/wait_queue.rs index ba8ff54..4ced6ab 100644 --- a/rtic-common/src/wait_queue.rs +++ b/rtic-common/src/wait_queue.rs @@ -58,7 +58,7 @@ impl LinkedList { // Clear the pointers in the node. head_ref.next.store(null_mut(), Self::R); head_ref.prev.store(null_mut(), Self::R); - head_ref.is_poped.store(true, Self::R); + head_ref.is_popped.store(true, Self::R); return Some(head_val); } @@ -102,7 +102,7 @@ pub struct Link { pub(crate) val: T, next: AtomicPtr>, prev: AtomicPtr>, - is_poped: AtomicBool, + is_popped: AtomicBool, _up: PhantomPinned, } @@ -115,14 +115,14 @@ impl Link { val, next: AtomicPtr::new(null_mut()), prev: AtomicPtr::new(null_mut()), - is_poped: AtomicBool::new(false), + is_popped: AtomicBool::new(false), _up: PhantomPinned, } } /// Return true if this link has been poped from the list. - pub fn is_poped(&self) -> bool { - self.is_poped.load(Self::R) + pub fn is_popped(&self) -> bool { + self.is_popped.load(Self::R) } /// Remove this link from a linked list. @@ -133,7 +133,7 @@ impl Link { let prev = self.prev.load(Self::R); let next = self.next.load(Self::R); - self.is_poped.store(true, Self::R); + self.is_popped.store(true, Self::R); match unsafe { (prev.as_ref(), next.as_ref()) } { (None, None) => { -- cgit v1.2.3 From fe77b4538d6cd506d1a18bdc9e17216dc61881db Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Henrik=20Tj=C3=A4der?= Date: Wed, 1 Feb 2023 21:55:05 +0100 Subject: Add alpha.0 and required Cargo fields --- rtic-common/Cargo.toml | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'rtic-common') diff --git a/rtic-common/Cargo.toml b/rtic-common/Cargo.toml index 258caae..35b0f72 100644 --- a/rtic-common/Cargo.toml +++ b/rtic-common/Cargo.toml @@ -1,7 +1,10 @@ [package] name = "rtic-common" -version = "1.0.0" +version = "1.0.0-alpha.0" edition = "2021" +categories = ["concurrency", "embedded", "no-std", "asynchronous"] +description = "rtic-common lib TODO" +license = "MIT OR Apache-2.0" # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html -- cgit v1.2.3 From c2d2b1ba38dd291cfcd7e32f11d725db0ec1cf85 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Henrik=20Tj=C3=A4der?= Date: Wed, 1 Feb 2023 22:11:50 +0100 Subject: Add authors to each Cargo.toml Copy-paste the default one used for the project --- rtic-common/Cargo.toml | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'rtic-common') diff --git a/rtic-common/Cargo.toml b/rtic-common/Cargo.toml index 35b0f72..726090a 100644 --- a/rtic-common/Cargo.toml +++ b/rtic-common/Cargo.toml @@ -1,7 +1,15 @@ [package] name = "rtic-common" version = "1.0.0-alpha.0" + edition = "2021" +authors = [ + "The Real-Time Interrupt-driven Concurrency developers", + "Emil Fresk ", + "Henrik Tjäder ", + "Jorge Aparicio ", + "Per Lindgren ", +] categories = ["concurrency", "embedded", "no-std", "asynchronous"] description = "rtic-common lib TODO" license = "MIT OR Apache-2.0" -- cgit v1.2.3 From 1cda61fbda205920517f7b63af90c97c38ff9af6 Mon Sep 17 00:00:00 2001 From: Emil Fresk Date: Sat, 18 Feb 2023 09:43:06 +0100 Subject: Make some linked list operations unsafe, and document their safety at usage --- rtic-common/src/lib.rs | 4 ++++ rtic-common/src/wait_queue.rs | 38 ++++++++++++++++++++------------------ 2 files changed, 24 insertions(+), 18 deletions(-) (limited to 'rtic-common') diff --git a/rtic-common/src/lib.rs b/rtic-common/src/lib.rs index b8b5e0d..03d0306 100644 --- a/rtic-common/src/lib.rs +++ b/rtic-common/src/lib.rs @@ -4,6 +4,10 @@ #![deny(missing_docs)] //deny_warnings_placeholder_for_ci +#[cfg(test)] +#[macro_use] +extern crate std; + pub mod dropper; pub mod wait_queue; pub mod waker_registration; diff --git a/rtic-common/src/wait_queue.rs b/rtic-common/src/wait_queue.rs index 4ced6ab..7387a98 100644 --- a/rtic-common/src/wait_queue.rs +++ b/rtic-common/src/wait_queue.rs @@ -68,7 +68,9 @@ impl LinkedList { } /// Put an element at the back of the queue. - pub fn push(&self, link: Pin<&mut Link>) { + /// + /// SAFETY: The link must live until it is removed from the queue. + pub unsafe fn push(&self, link: Pin<&Link>) { cs::with(|_| { // Make sure all previous writes are visible core::sync::atomic::fence(Ordering::SeqCst); @@ -76,17 +78,17 @@ impl LinkedList { let tail = self.tail.load(Self::R); // SAFETY: This datastructure does not move the underlying value. - let link = unsafe { link.get_unchecked_mut() }; + let link = link.get_ref(); if let Some(tail_ref) = unsafe { tail.as_ref() } { // Queue is not empty link.prev.store(tail, Self::R); - self.tail.store(link, Self::R); - tail_ref.next.store(link, Self::R); + self.tail.store(link as *const _ as *mut _, Self::R); + tail_ref.next.store(link as *const _ as *mut _, Self::R); } else { // Queue is empty - self.tail.store(link, Self::R); - self.head.store(link, Self::R); + self.tail.store(link as *const _ as *mut _, Self::R); + self.head.store(link as *const _ as *mut _, Self::R); } }); } @@ -126,7 +128,7 @@ impl Link { } /// Remove this link from a linked list. - pub fn remove_from_list(&mut self, list: &LinkedList) { + pub fn remove_from_list(&self, list: &LinkedList) { cs::with(|_| { // Make sure all previous writes are visible core::sync::atomic::fence(Ordering::SeqCst); @@ -230,17 +232,17 @@ mod tests { fn linked_list() { let wq = LinkedList::::new(); - let mut i1 = Link::new(10); - let mut i2 = Link::new(11); - let mut i3 = Link::new(12); - let mut i4 = Link::new(13); - let mut i5 = Link::new(14); - - wq.push(unsafe { Pin::new_unchecked(&mut i1) }); - wq.push(unsafe { Pin::new_unchecked(&mut i2) }); - wq.push(unsafe { Pin::new_unchecked(&mut i3) }); - wq.push(unsafe { Pin::new_unchecked(&mut i4) }); - wq.push(unsafe { Pin::new_unchecked(&mut i5) }); + let i1 = Link::new(10); + let i2 = Link::new(11); + let i3 = Link::new(12); + let i4 = Link::new(13); + let i5 = Link::new(14); + + unsafe { wq.push(Pin::new_unchecked(&i1)) }; + unsafe { wq.push(Pin::new_unchecked(&i2)) }; + unsafe { wq.push(Pin::new_unchecked(&i3)) }; + unsafe { wq.push(Pin::new_unchecked(&i4)) }; + unsafe { wq.push(Pin::new_unchecked(&i5)) }; wq.print(); -- cgit v1.2.3 From 5dc2c1d351d75d150d671994b1c67b2c0f9d16a0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Henrik=20Tj=C3=A4der?= Date: Sat, 4 Mar 2023 01:06:46 +0100 Subject: rtic-common: Fix safety section formatting --- rtic-common/src/wait_queue.rs | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'rtic-common') diff --git a/rtic-common/src/wait_queue.rs b/rtic-common/src/wait_queue.rs index 7387a98..b1aa775 100644 --- a/rtic-common/src/wait_queue.rs +++ b/rtic-common/src/wait_queue.rs @@ -69,7 +69,9 @@ impl LinkedList { /// Put an element at the back of the queue. /// - /// SAFETY: The link must live until it is removed from the queue. + /// # Safety + /// + /// The link must live until it is removed from the queue. pub unsafe fn push(&self, link: Pin<&Link>) { cs::with(|_| { // Make sure all previous writes are visible -- cgit v1.2.3