summaryrefslogtreecommitdiff
path: root/rust/kernel/lib.rs
blob: 1e910fe7c2c774af96171bf174ffc9ee6f945c52 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
// SPDX-License-Identifier: GPL-2.0

//! The `kernel` crate.
//!
//! This crate contains the kernel APIs that have been ported or wrapped for
//! usage by Rust code in the kernel and is shared by all of them.
//!
//! In other words, all the rest of the Rust code in the kernel (e.g. kernel
//! modules written in Rust) depends on [`core`], [`alloc`] and this crate.
//!
//! If you need a kernel C API that is not ported or wrapped yet here, then
//! do so first instead of bypassing this crate.

#![no_std]
#![feature(allocator_api)]
#![feature(coerce_unsized)]
#![feature(dispatch_from_dyn)]
#![feature(new_uninit)]
#![feature(receiver_trait)]
#![feature(unsize)]

// Ensure conditional compilation based on the kernel configuration works;
// otherwise we may silently break things like initcall handling.
#[cfg(not(CONFIG_RUST))]
compile_error!("Missing kernel configuration for conditional compilation");

// Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate).
extern crate self as kernel;

pub mod alloc;
mod build_assert;
pub mod error;
pub mod init;
pub mod ioctl;
#[cfg(CONFIG_KUNIT)]
pub mod kunit;
#[cfg(CONFIG_NET)]
pub mod net;
pub mod prelude;
pub mod print;
mod static_assert;
#[doc(hidden)]
pub mod std_vendor;
pub mod str;
pub mod sync;
pub mod task;
pub mod time;
pub mod types;
pub mod workqueue;

#[doc(hidden)]
pub use bindings;
pub use macros;
pub use uapi;

#[doc(hidden)]
pub use build_error::build_error;

/// Prefix to appear before log messages printed from within the `kernel` crate.
const __LOG_PREFIX: &[u8] = b"rust_kernel\0";

/// The top level entrypoint to implementing a kernel module.
///
/// For any teardown or cleanup operations, your type may implement [`Drop`].
pub trait Module: Sized + Sync {
    /// Called at module initialization time.
    ///
    /// Use this method to perform whatever setup or registration your module
    /// should do.
    ///
    /// Equivalent to the `module_init` macro in the C API.
    fn init(module: &'static ThisModule) -> error::Result<Self>;
}

/// Equivalent to `THIS_MODULE` in the C API.
///
/// C header: [`include/linux/export.h`](srctree/include/linux/export.h)
pub struct ThisModule(*mut bindings::module);

// SAFETY: `THIS_MODULE` may be used from all threads within a module.
unsafe impl Sync for ThisModule {}

impl ThisModule {
    /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
    ///
    /// # Safety
    ///
    /// The pointer must be equal to the right `THIS_MODULE`.
    pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
        ThisModule(ptr)
    }

    /// Access the raw pointer for this module.
    ///
    /// It is up to the user to use it correctly.
    pub const fn as_ptr(&self) -> *mut bindings::module {
        self.0
    }
}

#[cfg(not(any(testlib, test)))]
#[panic_handler]
fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
    pr_emerg!("{}\n", info);
    // SAFETY: FFI call.
    unsafe { bindings::BUG() };
}

/// Produces a pointer to an object from a pointer to one of its fields.
///
/// # Safety
///
/// The pointer passed to this macro, and the pointer returned by this macro, must both be in
/// bounds of the same allocation.
///
/// # Examples
///
/// ```
/// # use kernel::container_of;
/// struct Test {
///     a: u64,
///     b: u32,
/// }
///
/// let test = Test { a: 10, b: 20 };
/// let b_ptr = &test.b;
/// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be
/// // in-bounds of the same allocation as `b_ptr`.
/// let test_alias = unsafe { container_of!(b_ptr, Test, b) };
/// assert!(core::ptr::eq(&test, test_alias));
/// ```
#[macro_export]
macro_rules! container_of {
    ($ptr:expr, $type:ty, $($f:tt)*) => {{
        let ptr = $ptr as *const _ as *const u8;
        let offset: usize = ::core::mem::offset_of!($type, $($f)*);
        ptr.sub(offset) as *const $type
    }}
}