The following commit has been merged into the locking/core branch of tip:

Commit-ID:     c1f0451ec748f7a58a4e50bcb8f75bd89718be78
Gitweb:        https://git.kernel.org/tip/c1f0451ec748f7a58a4e50bcb8f75bd89718be78
Author:        Lyude Paul <lyude@redhat.com>
AuthorDate:    Fri, 07 Aug 2026 00:02:11 -07:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 10 Aug 2026 12:53:09 +02:00

rust: Introduce interrupt module

This introduces a module for dealing with interrupt-disabled contexts,
including the ability to enable and disable interrupts along with the
ability to annotate functions as expecting that IRQs are already
disabled on the local CPU.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260807070218.27144-15-boqun@kernel.org
---
 rust/helpers/helpers.c   |  1 +-
 rust/helpers/interrupt.c | 13 ++++++-
 rust/helpers/sync.c      |  5 ++-
 rust/kernel/interrupt.rs | 89 +++++++++++++++++++++++++++++++++++++++-
 rust/kernel/lib.rs       |  1 +-
 5 files changed, 109 insertions(+)
 create mode 100644 rust/helpers/interrupt.c
 create mode 100644 rust/kernel/interrupt.rs

diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index 998e310..0d85b5e 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -65,6 +65,7 @@
 #include "irq.c"
 #include "fs.c"
 #include "gpu.c"
+#include "interrupt.c"
 #include "io.c"
 #include "jump_label.c"
 #include "kunit.c"
diff --git a/rust/helpers/interrupt.c b/rust/helpers/interrupt.c
new file mode 100644
index 0000000..6959549
--- /dev/null
+++ b/rust/helpers/interrupt.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/spinlock.h>
+
+__rust_helper void rust_helper_local_interrupt_disable(void)
+{
+	local_interrupt_disable();
+}
+
+__rust_helper void rust_helper_local_interrupt_enable(void)
+{
+	local_interrupt_enable();
+}
diff --git a/rust/helpers/sync.c b/rust/helpers/sync.c
index 82d6aff..4f474fe 100644
--- a/rust/helpers/sync.c
+++ b/rust/helpers/sync.c
@@ -11,3 +11,8 @@ __rust_helper void rust_helper_lockdep_unregister_key(struct lock_class_key *k)
 {
 	lockdep_unregister_key(k);
 }
+
+__rust_helper void rust_helper_lockdep_assert_irqs_disabled(void)
+{
+	lockdep_assert_irqs_disabled();
+}
diff --git a/rust/kernel/interrupt.rs b/rust/kernel/interrupt.rs
new file mode 100644
index 0000000..a880ec3
--- /dev/null
+++ b/rust/kernel/interrupt.rs
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Interrupt controls
+//!
+//! This module allows Rust code to annotate areas of code where local processor interrupts should
+//! be disabled, along with actually disabling local processor interrupts.
+//!
+//! # ⚠️ Warning! ⚠️
+//!
+//! The usage of this module can be more complicated than meets the eye, especially surrounding
+//! [preemptible kernels]. It's recommended to take care when using the functions and types defined
+//! here and familiarize yourself with the various documentation we have before using them, along
+//! with the various documents we link to here.
+//!
+//! # Reading material
+//!
+//! - [Software interrupts and realtime (LWN)](https://lwn.net/Articles/520076)
+//!
+//! [preemptible kernels]: https://www.kernel.org/doc/html/latest/locking/preempt-locking.html
+
+use crate::types::NotThreadSafe;
+
+/// A guard that represents local processor interrupt disablement on preemptible kernels.
+///
+/// [`LocalInterruptDisabled`] is a guard type that represents that local processor interrupts have
+/// been disabled on a preemptible kernel.
+///
+/// Certain functions take an immutable reference of [`LocalInterruptDisabled`] in order to require
+/// that they may only be run in local-interrupt-disabled contexts on preemptible kernels.
+///
+/// This is a marker type; it has no size, and is simply used as a compile-time guarantee that local
+/// processor interrupts are disabled on preemptible kernels. Note that no guarantees about the
+/// state of interrupts are made by this type on non-preemptible kernels.
+///
+/// # Invariants
+///
+/// Local processor interrupts are disabled on preemptible kernels for as long as an object of this
+/// type exists.
+pub struct LocalInterruptDisabled(NotThreadSafe);
+
+/// Disable local processor interrupts on a preemptible kernel.
+///
+/// This function disables local processor interrupts on a preemptible kernel, and returns a
+/// [`LocalInterruptDisabled`] token as proof of this. On non-preemptible kernels, this function is
+/// a no-op.
+///
+/// **Usage of this function is discouraged** unless you are absolutely sure you know what you are
+/// doing, as kernel interfaces for Rust that deal with interrupt state will typically handle local
+/// processor interrupt state management on their own and managing this by hand is quite error
+/// prone.
+#[inline]
+pub fn local_interrupt_disable() -> LocalInterruptDisabled {
+    // SAFETY: It's always safe to call `local_interrupt_disable()`.
+    unsafe { bindings::local_interrupt_disable() };
+
+    LocalInterruptDisabled(NotThreadSafe)
+}
+
+impl Drop for LocalInterruptDisabled {
+    #[inline]
+    fn drop(&mut self) {
+        // SAFETY: Per type invariants, a `local_interrupt_disable()` must be called to create this
+        // object, hence calling the corresponding `local_interrupt_enable()` is safe.
+        unsafe { bindings::local_interrupt_enable() };
+    }
+}
+
+impl LocalInterruptDisabled {
+    /// Assume that local processor interrupts are disabled on preemptible kernels.
+    ///
+    /// This can be used for annotating code that is known to be run in contexts where local
+    /// processor interrupts are disabled on preemptible kernels. It makes no changes to the local
+    /// interrupt state on its own.
+    ///
+    /// # Safety
+    ///
+    /// For the whole life `'a`, local interrupts must be disabled on preemptible kernels. This
+    /// could be a context like, for example, an interrupt handler.
+    #[inline]
+    pub unsafe fn assume_disabled<'a>() -> &'a LocalInterruptDisabled {
+        const ASSUME_DISABLED: &LocalInterruptDisabled = &LocalInterruptDisabled(NotThreadSafe);
+
+        // Confirm they're actually disabled if lockdep is available
+        // SAFETY: It's always safe to call `lockdep_assert_irqs_disabled()`.
+        unsafe { bindings::lockdep_assert_irqs_disabled() };
+
+        ASSUME_DISABLED
+    }
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 9512af7..2ee6c24 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -82,6 +82,7 @@ pub mod id_pool;
 pub mod impl_flags;
 pub mod init;
 pub mod interop;
+pub mod interrupt;
 pub mod io;
 pub mod ioctl;
 pub mod iommu;