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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135// SPDX-License-Identifier: GPL-2.0
//! Commonly used sizes.//!//! C headers: [`include/linux/sizes.h`](srctree/include/linux/sizes.h).//!//! The top-level `SZ_*` constants are [`usize`]-typed, for use in kernel page//! arithmetic and similar CPU-side work.//!//! The [`SizeConstants`] trait provides the same constants as associated constants//! on [`u32`], [`u64`], and [`usize`], for use in device address spaces where//! the address width depends on the hardware. Device drivers frequently need//! these constants as [`u64`] (or [`u32`]) rather than [`usize`], because//! device address spaces are sized independently of the CPU pointer width.//!//! # Examples//!//! ```//! use kernel::{//! page::PAGE_SIZE,//! sizes::{//! SizeConstants,//! SZ_1M, ////! }, ////! };//!//! // Module-level constants continue to work without a type qualifier.//! let num_pages_in_1m = SZ_1M / PAGE_SIZE;//!//! // Trait associated constants require a type qualifier.//! let heap_size = 14 * u64::SZ_1M;//! let small = u32::SZ_4K;//! ```
macro_rules! define_sizes { ($($type:ty),* $(,)?) => { define_sizes!(@internal [$($type),*] /// `0x0000_0400`. SZ_1K, /// `0x0000_0800`. SZ_2K, /// `0x0000_1000`. SZ_4K, /// `0x0000_2000`. SZ_8K, /// `0x0000_4000`. SZ_16K, /// `0x0000_8000`. SZ_32K, /// `0x0001_0000`. SZ_64K, /// `0x0002_0000`. SZ_128K, /// `0x0004_0000`. SZ_256K, /// `0x0008_0000`. SZ_512K, /// `0x0010_0000`. SZ_1M, /// `0x0020_0000`. SZ_2M, /// `0x0040_0000`. SZ_4M, /// `0x0080_0000`. SZ_8M, /// `0x0100_0000`. SZ_16M, /// `0x0200_0000`. SZ_32M, /// `0x0400_0000`. SZ_64M, /// `0x0800_0000`. SZ_128M, /// `0x1000_0000`. SZ_256M, /// `0x2000_0000`. SZ_512M, /// `0x4000_0000`. SZ_1G, /// `0x8000_0000`. SZ_2G, ); };
(@internal [$($type:ty),*] $($names_and_metas:tt)*) => { define_sizes!(@consts_and_trait $($names_and_metas)*); define_sizes!(@impls [$($type),*] $($names_and_metas)*); };
(@consts_and_trait $($(#[$meta:meta])* $name:ident,)*) => { $( $(#[$meta])* pub const $name: usize = bindings::$name as usize; )*
/// Size constants for device address spaces. /// /// Implemented for [`u32`], [`u64`], and [`usize`] so drivers can /// choose the width that matches their hardware. All `SZ_*` values fit /// in a [`u32`], so all implementations are lossless. /// /// # Examples /// /// ``` /// use kernel::sizes::SizeConstants; /// /// let gpu_heap = 14 * u64::SZ_1M; /// let mmio_window = u32::SZ_16M; /// ``` pub trait SizeConstants { $( $(#[$meta])* const $name: Self; )* } };
(@impls [] $($(#[$meta:meta])* $name:ident,)*) => {};
(@impls [$first:ty $(, $rest:ty)*] $($(#[$meta:meta])* $name:ident,)*) => { impl SizeConstants for $first { $( const $name: Self = { assert!((self::$name as u128) <= (<$first>::MAX as u128)); self::$name as $first }; )* }
define_sizes!(@impls [$($rest),*] $($(#[$meta])* $name,)*); };}
define_sizes!(u32, u64, usize);