Merge tag 'rust-hrtimer-for-v6.15-v3' of https://github.com/Rust-for-Linux/linux into rust-next

Pull rust-hrtimer updates from Andreas Hindborg:
 "Introduce Rust support for the 'hrtimer' subsystem:

   - Add a way to use the 'hrtimer' subsystem from Rust. Rust code can
     now set up intrusive timers without allocating when starting the
     timer.

   - Add support for 'Pin<Box<_>>', 'Arc<_>', 'Pin<&_>' and
     'Pin<&mut _>' as pointer types for use with timer callbacks.

   - Add support for setting clock source and timer mode.

  'kernel' crate:

   - Add 'Arc::as_ptr' for converting an 'Arc' to a raw pointer. This is
     a dependency for the 'hrtimer' API.

   - Add 'Box::into_pin' for converting a 'Box<_>' into a 'Pin<Box<_>>'
     to align with Rust 'alloc'. This is a dependency for the 'hrtimer'
     API."

* tag 'rust-hrtimer-for-v6.15-v3' of https://github.com/Rust-for-Linux/linux:
  rust: hrtimer: add maintainer entry
  rust: hrtimer: add clocksource selection through `ClockId`
  rust: hrtimer: add `HrTimerMode`
  rust: hrtimer: implement `HrTimerPointer` for `Pin<Box<T>>`
  rust: alloc: add `Box::into_pin`
  rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&mut T>`
  rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&T>`
  rust: hrtimer: add `hrtimer::ScopedHrTimerPointer`
  rust: hrtimer: add `UnsafeHrTimerPointer`
  rust: hrtimer: allow timer restart from timer handler
  rust: hrtimer: implement `HrTimerPointer` for `Arc`
  rust: sync: add `Arc::as_ptr`
  rust: hrtimer: introduce hrtimer support

1 files changed, 68 insertions, 0 deletions

diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs
index 379c0f5772e5..f509cb0eb71e 100644
--- a/rust/kernel/time.rs
+++ b/rust/kernel/time.rs
@@ -8,6 +8,8 @@
 //! C header: [`include/linux/jiffies.h`](srctree/include/linux/jiffies.h).
 //! C header: [`include/linux/ktime.h`](srctree/include/linux/ktime.h).
 
+pub mod hrtimer;
+
 /// The number of nanoseconds per millisecond.
 pub const NSEC_PER_MSEC: i64 = bindings::NSEC_PER_MSEC as i64;
 
@@ -81,3 +83,69 @@ impl core::ops::Sub for Ktime {
         }
     }
 }
+
+/// An identifier for a clock. Used when specifying clock sources.
+///
+///
+/// Selection of the clock depends on the use case. In some cases the usage of a
+/// particular clock is mandatory, e.g. in network protocols, filesystems.In other
+/// cases the user of the clock has to decide which clock is best suited for the
+/// purpose. In most scenarios clock [`ClockId::Monotonic`] is the best choice as it
+/// provides a accurate monotonic notion of time (leap second smearing ignored).
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+#[repr(u32)]
+pub enum ClockId {
+    /// A settable system-wide clock that measures real (i.e., wall-clock) time.
+    ///
+    /// Setting this clock requires appropriate privileges. This clock is
+    /// affected by discontinuous jumps in the system time (e.g., if the system
+    /// administrator manually changes the clock), and by frequency adjustments
+    /// performed by NTP and similar applications via adjtime(3), adjtimex(2),
+    /// clock_adjtime(2), and ntp_adjtime(3). This clock normally counts the
+    /// number of seconds since 1970-01-01 00:00:00 Coordinated Universal Time
+    /// (UTC) except that it ignores leap seconds; near a leap second it may be
+    /// adjusted by leap second smearing to stay roughly in sync with UTC. Leap
+    /// second smearing applies frequency adjustments to the clock to speed up
+    /// or slow down the clock to account for the leap second without
+    /// discontinuities in the clock. If leap second smearing is not applied,
+    /// the clock will experience discontinuity around leap second adjustment.
+    RealTime = bindings::CLOCK_REALTIME,
+    /// A monotonically increasing clock.
+    ///
+    /// A nonsettable system-wide clock that represents monotonic time since—as
+    /// described by POSIX—"some unspecified point in the past". On Linux, that
+    /// point corresponds to the number of seconds that the system has been
+    /// running since it was booted.
+    ///
+    /// The CLOCK_MONOTONIC clock is not affected by discontinuous jumps in the
+    /// CLOCK_REAL (e.g., if the system administrator manually changes the
+    /// clock), but is affected by frequency adjustments. This clock does not
+    /// count time that the system is suspended.
+    Monotonic = bindings::CLOCK_MONOTONIC,
+    /// A monotonic that ticks while system is suspended.
+    ///
+    /// A nonsettable system-wide clock that is identical to CLOCK_MONOTONIC,
+    /// except that it also includes any time that the system is suspended. This
+    /// allows applications to get a suspend-aware monotonic clock without
+    /// having to deal with the complications of CLOCK_REALTIME, which may have
+    /// discontinuities if the time is changed using settimeofday(2) or similar.
+    BootTime = bindings::CLOCK_BOOTTIME,
+    /// International Atomic Time.
+    ///
+    /// A system-wide clock derived from wall-clock time but counting leap seconds.
+    ///
+    /// This clock is coupled to CLOCK_REALTIME and will be set when CLOCK_REALTIME is
+    /// set, or when the offset to CLOCK_REALTIME is changed via adjtimex(2). This
+    /// usually happens during boot and **should** not happen during normal operations.
+    /// However, if NTP or another application adjusts CLOCK_REALTIME by leap second
+    /// smearing, this clock will not be precise during leap second smearing.
+    ///
+    /// The acronym TAI refers to International Atomic Time.
+    TAI = bindings::CLOCK_TAI,
+}
+
+impl ClockId {
+    fn into_c(self) -> bindings::clockid_t {
+        self as bindings::clockid_t
+    }
+}