84 lines · rust
1// SPDX-License-Identifier: GPL-2.02 3//! Time related primitives.4//!5//! This module contains the kernel APIs related to time and timers that6//! have been ported or wrapped for usage by Rust code in the kernel.7//!8//! C header: [`include/linux/jiffies.h`](srctree/include/linux/jiffies.h).9//! C header: [`include/linux/ktime.h`](srctree/include/linux/ktime.h).10 11/// The number of nanoseconds per millisecond.12pub const NSEC_PER_MSEC: i64 = bindings::NSEC_PER_MSEC as i64;13 14/// The time unit of Linux kernel. One jiffy equals (1/HZ) second.15pub type Jiffies = core::ffi::c_ulong;16 17/// The millisecond time unit.18pub type Msecs = core::ffi::c_uint;19 20/// Converts milliseconds to jiffies.21#[inline]22pub fn msecs_to_jiffies(msecs: Msecs) -> Jiffies {23 // SAFETY: The `__msecs_to_jiffies` function is always safe to call no24 // matter what the argument is.25 unsafe { bindings::__msecs_to_jiffies(msecs) }26}27 28/// A Rust wrapper around a `ktime_t`.29#[repr(transparent)]30#[derive(Copy, Clone)]31pub struct Ktime {32 inner: bindings::ktime_t,33}34 35impl Ktime {36 /// Create a `Ktime` from a raw `ktime_t`.37 #[inline]38 pub fn from_raw(inner: bindings::ktime_t) -> Self {39 Self { inner }40 }41 42 /// Get the current time using `CLOCK_MONOTONIC`.43 #[inline]44 pub fn ktime_get() -> Self {45 // SAFETY: It is always safe to call `ktime_get` outside of NMI context.46 Self::from_raw(unsafe { bindings::ktime_get() })47 }48 49 /// Divide the number of nanoseconds by a compile-time constant.50 #[inline]51 fn divns_constant<const DIV: i64>(self) -> i64 {52 self.to_ns() / DIV53 }54 55 /// Returns the number of nanoseconds.56 #[inline]57 pub fn to_ns(self) -> i64 {58 self.inner59 }60 61 /// Returns the number of milliseconds.62 #[inline]63 pub fn to_ms(self) -> i64 {64 self.divns_constant::<NSEC_PER_MSEC>()65 }66}67 68/// Returns the number of milliseconds between two ktimes.69#[inline]70pub fn ktime_ms_delta(later: Ktime, earlier: Ktime) -> i64 {71 (later - earlier).to_ms()72}73 74impl core::ops::Sub for Ktime {75 type Output = Ktime;76 77 #[inline]78 fn sub(self, other: Ktime) -> Ktime {79 Self {80 inner: self.inner - other.inner,81 }82 }83}84