1 // SPDX-License-Identifier: GPL-2.0 2 3 //! Time related primitives. 4 //! 5 //! This module contains the kernel APIs related to time and timers that 6 //! 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 pub mod hrtimer; 12 13 /// The number of nanoseconds per millisecond. 14 pub const NSEC_PER_MSEC: i64 = bindings::NSEC_PER_MSEC as i64; 15 16 /// The time unit of Linux kernel. One jiffy equals (1/HZ) second. 17 pub type Jiffies = crate::ffi::c_ulong; 18 19 /// The millisecond time unit. 20 pub type Msecs = crate::ffi::c_uint; 21 22 /// Converts milliseconds to jiffies. 23 #[inline] 24 pub fn msecs_to_jiffies(msecs: Msecs) -> Jiffies { 25 // SAFETY: The `__msecs_to_jiffies` function is always safe to call no 26 // matter what the argument is. 27 unsafe { bindings::__msecs_to_jiffies(msecs) } 28 } 29 30 /// A Rust wrapper around a `ktime_t`. 31 #[repr(transparent)] 32 #[derive(Copy, Clone)] 33 pub struct Ktime { 34 inner: bindings::ktime_t, 35 } 36 37 impl Ktime { 38 /// Create a `Ktime` from a raw `ktime_t`. 39 #[inline] 40 pub fn from_raw(inner: bindings::ktime_t) -> Self { 41 Self { inner } 42 } 43 44 /// Get the current time using `CLOCK_MONOTONIC`. 45 #[inline] 46 pub fn ktime_get() -> Self { 47 // SAFETY: It is always safe to call `ktime_get` outside of NMI context. 48 Self::from_raw(unsafe { bindings::ktime_get() }) 49 } 50 51 /// Divide the number of nanoseconds by a compile-time constant. 52 #[inline] 53 fn divns_constant<const DIV: i64>(self) -> i64 { 54 self.to_ns() / DIV 55 } 56 57 /// Returns the number of nanoseconds. 58 #[inline] 59 pub fn to_ns(self) -> i64 { 60 self.inner 61 } 62 63 /// Returns the number of milliseconds. 64 #[inline] 65 pub fn to_ms(self) -> i64 { 66 self.divns_constant::<NSEC_PER_MSEC>() 67 } 68 } 69 70 /// Returns the number of milliseconds between two ktimes. 71 #[inline] 72 pub fn ktime_ms_delta(later: Ktime, earlier: Ktime) -> i64 { 73 (later - earlier).to_ms() 74 } 75 76 impl core::ops::Sub for Ktime { 77 type Output = Ktime; 78 79 #[inline] 80 fn sub(self, other: Ktime) -> Ktime { 81 Self { 82 inner: self.inner - other.inner, 83 } 84 } 85 } 86