| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20241018055125.2784186-5-boqun.feng@gmail.com>
Date: Thu, 17 Oct 2024 22:51:23 -0700
From: Boqun Feng <boqun.feng@...il.com>
To: "Thomas Gleixner" <tglx@...utronix.de>
Cc: Dirk Behme <dirk.behme@...il.com>,
Lyude Paul <lyude@...hat.com>,
rust-for-linux@...r.kernel.org,
Danilo Krummrich <dakr@...hat.com>,
airlied@...hat.com,
Ingo Molnar <mingo@...hat.com>,
will@...nel.org,
Waiman Long <longman@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
linux-kernel@...r.kernel.org,
Miguel Ojeda <ojeda@...nel.org>,
Alex Gaynor <alex.gaynor@...il.com>,
wedsonaf@...il.com,
Gary Guo <gary@...yguo.net>,
Björn Roy Baron <bjorn3_gh@...tonmail.com>,
Benno Lossin <benno.lossin@...ton.me>,
Andreas Hindborg <a.hindborg@...sung.com>,
aliceryhl@...gle.com,
Trevor Gross <tmgross@...ch.edu>,
Boqun Feng <boqun.feng@...il.com>
Subject: [POC 4/6] rust: sync: Add SpinLockIrq
From: Lyude Paul <lyude@...hat.com>
A variant of SpinLock that is expected to be used in noirq contexts, so
lock() will disable interrupts and unlock() (i.e. `Guard::drop()` will
undo the interrupt disable.
[Boqun: Port to use spin_lock_irq_disable() and
spin_unlock_irq_enable()]
Co-developed-by: Lyude Paul <lyude@...hat.com>
Signed-off-by: Lyude Paul <lyude@...hat.com>
Signed-off-by: Boqun Feng <boqun.feng@...il.com>
---
rust/kernel/sync.rs | 2 +-
rust/kernel/sync/lock/spinlock.rs | 91 +++++++++++++++++++++++++++++++
2 files changed, 92 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
index 0ab20975a3b5..b028ee325f2a 100644
--- a/rust/kernel/sync.rs
+++ b/rust/kernel/sync.rs
@@ -15,7 +15,7 @@
pub use arc::{Arc, ArcBorrow, UniqueArc};
pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult};
pub use lock::mutex::{new_mutex, Mutex};
-pub use lock::spinlock::{new_spinlock, SpinLock};
+pub use lock::spinlock::{new_spinlock, new_spinlock_irq, SpinLock, SpinLockIrq};
pub use locked_by::LockedBy;
/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.
diff --git a/rust/kernel/sync/lock/spinlock.rs b/rust/kernel/sync/lock/spinlock.rs
index ea5c5bc1ce12..884d4d1cbf23 100644
--- a/rust/kernel/sync/lock/spinlock.rs
+++ b/rust/kernel/sync/lock/spinlock.rs
@@ -115,3 +115,94 @@ unsafe fn unlock(ptr: *mut Self::State, _guard_state: &Self::GuardState) {
unsafe { bindings::spin_unlock(ptr) }
}
}
+
+/// Creates a [`SpinLockIrq`] initialiser with the given name and a newly-created lock class.
+///
+/// It uses the name if one is given, otherwise it generates one based on the file name and line
+/// number.
+#[macro_export]
+macro_rules! new_spinlock_irq {
+ ($inner:expr $(, $name:literal)? $(,)?) => {
+ $crate::sync::SpinLockIrq::new(
+ $inner, $crate::optional_name!($($name)?), $crate::static_lock_class!())
+ };
+}
+pub use new_spinlock_irq;
+
+/// A spinlock that may be acquired when interrupts are disabled.
+///
+/// A version of [`SpinLock`] that can only be used in contexts where interrupts for the local CPU
+/// are disabled. It requires that the user acquiring the lock provide proof that interrupts are
+/// disabled through [`IrqDisabled`].
+///
+/// For more info, see [`SpinLock`].
+///
+/// # Examples
+///
+/// The following example shows how to declare, allocate initialise and access a struct (`Example`)
+/// that contains an inner struct (`Inner`) that is protected by a spinlock.
+///
+/// ```
+/// use kernel::sync::{new_spinlock_irq, SpinLockIrq};
+///
+/// struct Inner {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// #[pin_data]
+/// struct Example {
+/// c: u32,
+/// #[pin]
+/// d: SpinLockIrq<Inner>,
+/// }
+///
+/// impl Example {
+/// fn new() -> impl PinInit<Self> {
+/// pin_init!(Self {
+/// c: 10,
+/// d <- new_spinlock_irq!(Inner { a: 20, b: 30 }),
+/// })
+/// }
+/// }
+///
+/// // Allocate a boxed `Example`
+/// let e = Box::pin_init(Example::new(), GFP_KERNEL)?;
+///
+/// // Accessing an `Example` from a context where IRQs may not be disabled already.
+/// let b = e.d.lock().b;
+///
+/// assert_eq!(b, 30);
+/// # Ok::<(), Error>(())
+/// ```
+pub type SpinLockIrq<T> = super::Lock<T, SpinLockIrqBackend>;
+
+/// A kernel `spinlock_t` lock backend that is acquired in interrupt disabled contexts.
+pub struct SpinLockIrqBackend;
+
+unsafe impl super::Backend for SpinLockIrqBackend {
+ type State = bindings::spinlock_t;
+ type GuardState = ();
+
+ unsafe fn init(
+ ptr: *mut Self::State,
+ name: *const core::ffi::c_char,
+ key: *mut bindings::lock_class_key,
+ ) {
+ // SAFETY: The safety requirements ensure that `ptr` is valid for writes, and `name` and
+ // `key` are valid for read indefinitely.
+ unsafe { bindings::__spin_lock_init(ptr, name, key) }
+ }
+
+ unsafe fn lock(ptr: *mut Self::State) -> Self::GuardState {
+ // SAFETY: The safety requirements of this function ensure that `ptr` points to valid
+ // memory, and that it has been initialised before.
+ unsafe { bindings::spin_lock_irq_disable(ptr) }
+ }
+
+ unsafe fn unlock(ptr: *mut Self::State, _guard_state: &Self::GuardState) {
+ // SAFETY: The safety requirements of this function ensure that `ptr` is valid and that the
+ // caller is the owner of the spinlock.
+ unsafe { bindings::spin_unlock_irq_enable(ptr) }
+ }
+}
--
2.45.2
Powered by blists - more mailing lists