1 // SPDX-License-Identifier: GPL-2.0
2
3 use crate::helpers::*;
4 use proc_macro::{token_stream, Delimiter, Literal, TokenStream, TokenTree};
5 use std::fmt::Write;
6
7 fn expect_string_array(it: &mut token_stream::IntoIter) -> Vec<String> {
8 let group = expect_group(it);
9 assert_eq!(group.delimiter(), Delimiter::Bracket);
10 let mut values = Vec::new();
11 let mut it = group.stream().into_iter();
12
13 while let Some(val) = try_string(&mut it) {
14 assert!(val.is_ascii(), "Expected ASCII string");
15 values.push(val);
16 match it.next() {
17 Some(TokenTree::Punct(punct)) => assert_eq!(punct.as_char(), ','),
18 None => break,
19 _ => panic!("Expected ',' or end of array"),
20 }
21 }
22 values
23 }
24
25 struct ModInfoBuilder<'a> {
26 module: &'a str,
27 counter: usize,
28 buffer: String,
29 }
30
31 impl<'a> ModInfoBuilder<'a> {
32 fn new(module: &'a str) -> Self {
33 ModInfoBuilder {
34 module,
35 counter: 0,
36 buffer: String::new(),
37 }
38 }
39
40 fn emit_base(&mut self, field: &str, content: &str, builtin: bool) {
41 let string = if builtin {
42 // Built-in modules prefix their modinfo strings by `module.`.
43 format!(
44 "{module}.{field}={content}\0",
45 module = self.module,
46 field = field,
47 content = content
48 )
49 } else {
50 // Loadable modules' modinfo strings go as-is.
51 format!("{field}={content}\0", field = field, content = content)
52 };
53
54 write!(
55 &mut self.buffer,
56 "
57 {cfg}
58 #[doc(hidden)]
59 #[link_section = \".modinfo\"]
60 #[used]
61 pub static __{module}_{counter}: [u8; {length}] = *{string};
62 ",
63 cfg = if builtin {
64 "#[cfg(not(MODULE))]"
65 } else {
66 "#[cfg(MODULE)]"
67 },
68 module = self.module.to_uppercase(),
69 counter = self.counter,
70 length = string.len(),
71 string = Literal::byte_string(string.as_bytes()),
72 )
73 .unwrap();
74
75 self.counter += 1;
76 }
77
78 fn emit_only_builtin(&mut self, field: &str, content: &str) {
79 self.emit_base(field, content, true)
80 }
81
82 fn emit_only_loadable(&mut self, field: &str, content: &str) {
83 self.emit_base(field, content, false)
84 }
85
86 fn emit(&mut self, field: &str, content: &str) {
87 self.emit_only_builtin(field, content);
88 self.emit_only_loadable(field, content);
89 }
90 }
91
92 #[derive(Debug, Default)]
93 struct ModuleInfo {
94 type_: String,
95 license: String,
96 name: String,
97 author: Option<String>,
98 description: Option<String>,
99 alias: Option<Vec<String>>,
100 firmware: Option<Vec<String>>,
101 }
102
103 impl ModuleInfo {
104 fn parse(it: &mut token_stream::IntoIter) -> Self {
105 let mut info = ModuleInfo::default();
106
107 const EXPECTED_KEYS: &[&str] = &[
108 "type",
109 "name",
110 "author",
111 "description",
112 "license",
113 "alias",
114 "firmware",
115 ];
116 const REQUIRED_KEYS: &[&str] = &["type", "name", "license"];
117 let mut seen_keys = Vec::new();
118
119 loop {
120 let key = match it.next() {
121 Some(TokenTree::Ident(ident)) => ident.to_string(),
122 Some(_) => panic!("Expected Ident or end"),
123 None => break,
124 };
125
126 if seen_keys.contains(&key) {
127 panic!(
128 "Duplicated key \"{}\". Keys can only be specified once.",
129 key
130 );
131 }
132
133 assert_eq!(expect_punct(it), ':');
134
135 match key.as_str() {
136 "type" => info.type_ = expect_ident(it),
137 "name" => info.name = expect_string_ascii(it),
138 "author" => info.author = Some(expect_string(it)),
139 "description" => info.description = Some(expect_string(it)),
140 "license" => info.license = expect_string_ascii(it),
141 "alias" => info.alias = Some(expect_string_array(it)),
142 "firmware" => info.firmware = Some(expect_string_array(it)),
143 _ => panic!(
144 "Unknown key \"{}\". Valid keys are: {:?}.",
145 key, EXPECTED_KEYS
146 ),
147 }
148
149 assert_eq!(expect_punct(it), ',');
150
151 seen_keys.push(key);
152 }
153
154 expect_end(it);
155
156 for key in REQUIRED_KEYS {
157 if !seen_keys.iter().any(|e| e == key) {
158 panic!("Missing required key \"{}\".", key);
159 }
160 }
161
162 let mut ordered_keys: Vec<&str> = Vec::new();
163 for key in EXPECTED_KEYS {
164 if seen_keys.iter().any(|e| e == key) {
165 ordered_keys.push(key);
166 }
167 }
168
169 if seen_keys != ordered_keys {
170 panic!(
171 "Keys are not ordered as expected. Order them like: {:?}.",
172 ordered_keys
173 );
174 }
175
176 info
177 }
178 }
179
180 pub(crate) fn module(ts: TokenStream) -> TokenStream {
181 let mut it = ts.into_iter();
182
183 let info = ModuleInfo::parse(&mut it);
184
185 let mut modinfo = ModInfoBuilder::new(info.name.as_ref());
186 if let Some(author) = info.author {
187 modinfo.emit("author", &author);
188 }
189 if let Some(description) = info.description {
190 modinfo.emit("description", &description);
191 }
192 modinfo.emit("license", &info.license);
193 if let Some(aliases) = info.alias {
194 for alias in aliases {
195 modinfo.emit("alias", &alias);
196 }
197 }
198 if let Some(firmware) = info.firmware {
199 for fw in firmware {
200 modinfo.emit("firmware", &fw);
201 }
202 }
203
204 // Built-in modules also export the `file` modinfo string.
205 let file =
206 std::env::var("RUST_MODFILE").expect("Unable to fetch RUST_MODFILE environmental variable");
207 modinfo.emit_only_builtin("file", &file);
208
209 format!(
210 "
211 /// The module name.
212 ///
213 /// Used by the printing macros, e.g. [`info!`].
214 const __LOG_PREFIX: &[u8] = b\"{name}\\0\";
215
216 // SAFETY: `__this_module` is constructed by the kernel at load time and will not be
217 // freed until the module is unloaded.
218 #[cfg(MODULE)]
219 static THIS_MODULE: kernel::ThisModule = unsafe {{
220 extern \"C\" {{
221 static __this_module: kernel::types::Opaque<kernel::bindings::module>;
222 }}
223
224 kernel::ThisModule::from_ptr(__this_module.get())
225 }};
226 #[cfg(not(MODULE))]
227 static THIS_MODULE: kernel::ThisModule = unsafe {{
228 kernel::ThisModule::from_ptr(core::ptr::null_mut())
229 }};
230
231 // Double nested modules, since then nobody can access the public items inside.
232 mod __module_init {{
233 mod __module_init {{
234 use super::super::{type_};
235
236 /// The \"Rust loadable module\" mark.
237 //
238 // This may be best done another way later on, e.g. as a new modinfo
239 // key or a new section. For the moment, keep it simple.
240 #[cfg(MODULE)]
241 #[doc(hidden)]
242 #[used]
243 static __IS_RUST_MODULE: () = ();
244
245 static mut __MOD: Option<{type_}> = None;
246
247 // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
248 /// # Safety
249 ///
250 /// This function must not be called after module initialization, because it may be
251 /// freed after that completes.
252 #[cfg(MODULE)]
253 #[doc(hidden)]
254 #[no_mangle]
255 #[link_section = \".init.text\"]
256 pub unsafe extern \"C\" fn init_module() -> core::ffi::c_int {{
257 // SAFETY: This function is inaccessible to the outside due to the double
258 // module wrapping it. It is called exactly once by the C side via its
259 // unique name.
260 unsafe {{ __init() }}
261 }}
262
263 #[cfg(MODULE)]
264 #[doc(hidden)]
265 #[used]
266 #[link_section = \".init.data\"]
267 static __UNIQUE_ID___addressable_init_module: unsafe extern \"C\" fn() -> i32 = init_module;
268
269 #[cfg(MODULE)]
270 #[doc(hidden)]
271 #[no_mangle]
272 pub extern \"C\" fn cleanup_module() {{
273 // SAFETY:
274 // - This function is inaccessible to the outside due to the double
275 // module wrapping it. It is called exactly once by the C side via its
276 // unique name,
277 // - furthermore it is only called after `init_module` has returned `0`
278 // (which delegates to `__init`).
279 unsafe {{ __exit() }}
280 }}
281
282 #[cfg(MODULE)]
283 #[doc(hidden)]
284 #[used]
285 #[link_section = \".exit.data\"]
286 static __UNIQUE_ID___addressable_cleanup_module: extern \"C\" fn() = cleanup_module;
287
288 // Built-in modules are initialized through an initcall pointer
289 // and the identifiers need to be unique.
290 #[cfg(not(MODULE))]
291 #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
292 #[doc(hidden)]
293 #[link_section = \"{initcall_section}\"]
294 #[used]
295 pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init;
296
297 #[cfg(not(MODULE))]
298 #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
299 core::arch::global_asm!(
300 r#\".section \"{initcall_section}\", \"a\"
301 __{name}_initcall:
302 .long __{name}_init - .
303 .previous
304 \"#
305 );
306
307 #[cfg(not(MODULE))]
308 #[doc(hidden)]
309 #[no_mangle]
310 pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{
311 // SAFETY: This function is inaccessible to the outside due to the double
312 // module wrapping it. It is called exactly once by the C side via its
313 // placement above in the initcall section.
314 unsafe {{ __init() }}
315 }}
316
317 #[cfg(not(MODULE))]
318 #[doc(hidden)]
319 #[no_mangle]
320 pub extern \"C\" fn __{name}_exit() {{
321 // SAFETY:
322 // - This function is inaccessible to the outside due to the double
323 // module wrapping it. It is called exactly once by the C side via its
324 // unique name,
325 // - furthermore it is only called after `__{name}_init` has returned `0`
326 // (which delegates to `__init`).
327 unsafe {{ __exit() }}
328 }}
329
330 /// # Safety
331 ///
332 /// This function must only be called once.
333 unsafe fn __init() -> core::ffi::c_int {{
334 match <{type_} as kernel::Module>::init(&super::super::THIS_MODULE) {{
335 Ok(m) => {{
336 // SAFETY: No data race, since `__MOD` can only be accessed by this
337 // module and there only `__init` and `__exit` access it. These
338 // functions are only called once and `__exit` cannot be called
339 // before or during `__init`.
340 unsafe {{
341 __MOD = Some(m);
342 }}
343 return 0;
344 }}
345 Err(e) => {{
346 return e.to_errno();
347 }}
348 }}
349 }}
350
351 /// # Safety
352 ///
353 /// This function must
354 /// - only be called once,
355 /// - be called after `__init` has been called and returned `0`.
356 unsafe fn __exit() {{
357 // SAFETY: No data race, since `__MOD` can only be accessed by this module
358 // and there only `__init` and `__exit` access it. These functions are only
359 // called once and `__init` was already called.
360 unsafe {{
361 // Invokes `drop()` on `__MOD`, which should be used for cleanup.
362 __MOD = None;
363 }}
364 }}
365
366 {modinfo}
367 }}
368 }}
369 ",
370 type_ = info.type_,
371 name = info.name,
372 modinfo = modinfo.buffer,
373 initcall_section = ".initcall6.init"
374 )
375 .parse()
376 .expect("Error parsing formatted string into token stream.")
377 }
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