projects/linux·blob master · refs

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1// SPDX-License-Identifier: GPL-2.0
2
3//! Rust printing macros sample.
4
5use kernel::pr_cont;
6use kernel::prelude::*;
7
8module! {
9 type: RustPrint,
10 name: "rust_print",
11 authors: ["Rust for Linux Contributors"],
12 description: "Rust printing macros sample",
13 license: "GPL",
14}
15
16struct RustPrint;
17
18#[expect(clippy::disallowed_macros)]
19fn arc_print() -> Result {
20 use kernel::sync::*;
21
22 let a = Arc::new(1, GFP_KERNEL)?;
23 let b = UniqueArc::new("hello, world", GFP_KERNEL)?;
24
25 // Prints the value of data in `a`.
26 pr_info!("{}\n", a);
27
28 // Uses ":?" to print debug fmt of `b`.
29 pr_info!("{:?}\n", b);
30
31 let a: Arc<&str> = b.into();
32 let c = a.clone();
33
34 // Uses `dbg` to print, will move `c` (for temporary debugging purposes).
35 dbg!(c);
36
37 {
38 // `Arc` can be used to delegate dynamic dispatch and the following is an example.
39 // Both `i32` and `&str` implement `Display`. This enables us to express a unified
40 // behaviour, contract or protocol on both `i32` and `&str` into a single `Arc` of
41 // type `Arc<dyn Display>`.
42
43 use kernel::fmt::Display;
44 fn arc_dyn_print(arc: &Arc<dyn Display>) {
45 pr_info!("Arc<dyn Display> says {arc}\n");
46 }
47
48 let a_i32_display: Arc<dyn Display> = Arc::new(42i32, GFP_KERNEL)?;
49 let a_str_display: Arc<dyn Display> = a.clone();
50
51 arc_dyn_print(&a_i32_display);
52 arc_dyn_print(&a_str_display);
53 }
54
55 // Pretty-prints the debug formatting with lower-case hexadecimal integers.
56 pr_info!("{:#x?}\n", a);
57
58 Ok(())
59}
60
61impl kernel::Module for RustPrint {
62 fn init(_module: &'static ThisModule) -> Result<Self> {
63 pr_info!("Rust printing macros sample (init)\n");
64
65 pr_emerg!("Emergency message (level 0) without args\n");
66 pr_alert!("Alert message (level 1) without args\n");
67 pr_crit!("Critical message (level 2) without args\n");
68 pr_err!("Error message (level 3) without args\n");
69 pr_warn!("Warning message (level 4) without args\n");
70 pr_notice!("Notice message (level 5) without args\n");
71 pr_info!("Info message (level 6) without args\n");
72
73 pr_info!("A line that");
74 pr_cont!(" is continued");
75 pr_cont!(" without args\n");
76
77 pr_emerg!("{} message (level {}) with args\n", "Emergency", 0);
78 pr_alert!("{} message (level {}) with args\n", "Alert", 1);
79 pr_crit!("{} message (level {}) with args\n", "Critical", 2);
80 pr_err!("{} message (level {}) with args\n", "Error", 3);
81 pr_warn!("{} message (level {}) with args\n", "Warning", 4);
82 pr_notice!("{} message (level {}) with args\n", "Notice", 5);
83 pr_info!("{} message (level {}) with args\n", "Info", 6);
84
85 pr_info!("A {} that", "line");
86 pr_cont!(" is {}", "continued");
87 pr_cont!(" with {}\n", "args");
88
89 arc_print()?;
90
91 trace::trace_rust_sample_loaded(42);
92
93 Ok(RustPrint)
94 }
95}
96
97impl Drop for RustPrint {
98 fn drop(&mut self) {
99 pr_info!("Rust printing macros sample (exit)\n");
100 }
101}
102
103mod trace {
104 use kernel::prelude::*;
105
106 kernel::declare_trace! {
107 /// # Safety
108 ///
109 /// Always safe to call.
110 unsafe fn rust_sample_loaded(magic: c_int);
111 }
112
113 pub(crate) fn trace_rust_sample_loaded(magic: i32) {
114 // SAFETY: Always safe to call.
115 unsafe { rust_sample_loaded(magic as c_int) }
116 }
117}