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
expect_string_array(it: &mut token_stream::IntoIter) -> Vec<String>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> {
new(module: &'a str) -> Self32 fn new(module: &'a str) -> Self {
33 ModInfoBuilder {
34 module,
35 counter: 0,
36 buffer: String::new(),
37 }
38 }
39
emit_base(&mut self, field: &str, content: &str, builtin: bool)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
emit_only_builtin(&mut self, field: &str, content: &str)78 fn emit_only_builtin(&mut self, field: &str, content: &str) {
79 self.emit_base(field, content, true)
80 }
81
emit_only_loadable(&mut self, field: &str, content: &str)82 fn emit_only_loadable(&mut self, field: &str, content: &str) {
83 self.emit_base(field, content, false)
84 }
85
emit(&mut self, field: &str, content: &str)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 }
101
102 impl ModuleInfo {
parse(it: &mut token_stream::IntoIter) -> Self103 fn parse(it: &mut token_stream::IntoIter) -> Self {
104 let mut info = ModuleInfo::default();
105
106 const EXPECTED_KEYS: &[&str] =
107 &["type", "name", "author", "description", "license", "alias"];
108 const REQUIRED_KEYS: &[&str] = &["type", "name", "license"];
109 let mut seen_keys = Vec::new();
110
111 loop {
112 let key = match it.next() {
113 Some(TokenTree::Ident(ident)) => ident.to_string(),
114 Some(_) => panic!("Expected Ident or end"),
115 None => break,
116 };
117
118 if seen_keys.contains(&key) {
119 panic!(
120 "Duplicated key \"{}\". Keys can only be specified once.",
121 key
122 );
123 }
124
125 assert_eq!(expect_punct(it), ':');
126
127 match key.as_str() {
128 "type" => info.type_ = expect_ident(it),
129 "name" => info.name = expect_string_ascii(it),
130 "author" => info.author = Some(expect_string(it)),
131 "description" => info.description = Some(expect_string(it)),
132 "license" => info.license = expect_string_ascii(it),
133 "alias" => info.alias = Some(expect_string_array(it)),
134 _ => panic!(
135 "Unknown key \"{}\". Valid keys are: {:?}.",
136 key, EXPECTED_KEYS
137 ),
138 }
139
140 assert_eq!(expect_punct(it), ',');
141
142 seen_keys.push(key);
143 }
144
145 expect_end(it);
146
147 for key in REQUIRED_KEYS {
148 if !seen_keys.iter().any(|e| e == key) {
149 panic!("Missing required key \"{}\".", key);
150 }
151 }
152
153 let mut ordered_keys: Vec<&str> = Vec::new();
154 for key in EXPECTED_KEYS {
155 if seen_keys.iter().any(|e| e == key) {
156 ordered_keys.push(key);
157 }
158 }
159
160 if seen_keys != ordered_keys {
161 panic!(
162 "Keys are not ordered as expected. Order them like: {:?}.",
163 ordered_keys
164 );
165 }
166
167 info
168 }
169 }
170
module(ts: TokenStream) -> TokenStream171 pub(crate) fn module(ts: TokenStream) -> TokenStream {
172 let mut it = ts.into_iter();
173
174 let info = ModuleInfo::parse(&mut it);
175
176 let mut modinfo = ModInfoBuilder::new(info.name.as_ref());
177 if let Some(author) = info.author {
178 modinfo.emit("author", &author);
179 }
180 if let Some(description) = info.description {
181 modinfo.emit("description", &description);
182 }
183 modinfo.emit("license", &info.license);
184 if let Some(aliases) = info.alias {
185 for alias in aliases {
186 modinfo.emit("alias", &alias);
187 }
188 }
189
190 // Built-in modules also export the `file` modinfo string.
191 let file =
192 std::env::var("RUST_MODFILE").expect("Unable to fetch RUST_MODFILE environmental variable");
193 modinfo.emit_only_builtin("file", &file);
194
195 format!(
196 "
197 /// The module name.
198 ///
199 /// Used by the printing macros, e.g. [`info!`].
200 const __LOG_PREFIX: &[u8] = b\"{name}\\0\";
201
202 // SAFETY: `__this_module` is constructed by the kernel at load time and will not be
203 // freed until the module is unloaded.
204 #[cfg(MODULE)]
205 static THIS_MODULE: kernel::ThisModule = unsafe {{
206 extern \"C\" {{
207 static __this_module: kernel::types::Opaque<kernel::bindings::module>;
208 }}
209
210 kernel::ThisModule::from_ptr(__this_module.get())
211 }};
212 #[cfg(not(MODULE))]
213 static THIS_MODULE: kernel::ThisModule = unsafe {{
214 kernel::ThisModule::from_ptr(core::ptr::null_mut())
215 }};
216
217 // Double nested modules, since then nobody can access the public items inside.
218 mod __module_init {{
219 mod __module_init {{
220 use super::super::{type_};
221
222 /// The \"Rust loadable module\" mark.
223 //
224 // This may be best done another way later on, e.g. as a new modinfo
225 // key or a new section. For the moment, keep it simple.
226 #[cfg(MODULE)]
227 #[doc(hidden)]
228 #[used]
229 static __IS_RUST_MODULE: () = ();
230
231 static mut __MOD: Option<{type_}> = None;
232
233 // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
234 /// # Safety
235 ///
236 /// This function must not be called after module initialization, because it may be
237 /// freed after that completes.
238 #[cfg(MODULE)]
239 #[doc(hidden)]
240 #[no_mangle]
241 #[link_section = \".init.text\"]
242 pub unsafe extern \"C\" fn init_module() -> core::ffi::c_int {{
243 // SAFETY: This function is inaccessible to the outside due to the double
244 // module wrapping it. It is called exactly once by the C side via its
245 // unique name.
246 unsafe {{ __init() }}
247 }}
248
249 #[cfg(MODULE)]
250 #[doc(hidden)]
251 #[no_mangle]
252 pub extern \"C\" fn cleanup_module() {{
253 // SAFETY:
254 // - This function is inaccessible to the outside due to the double
255 // module wrapping it. It is called exactly once by the C side via its
256 // unique name,
257 // - furthermore it is only called after `init_module` has returned `0`
258 // (which delegates to `__init`).
259 unsafe {{ __exit() }}
260 }}
261
262 // Built-in modules are initialized through an initcall pointer
263 // and the identifiers need to be unique.
264 #[cfg(not(MODULE))]
265 #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
266 #[doc(hidden)]
267 #[link_section = \"{initcall_section}\"]
268 #[used]
269 pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init;
270
271 #[cfg(not(MODULE))]
272 #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
273 core::arch::global_asm!(
274 r#\".section \"{initcall_section}\", \"a\"
275 __{name}_initcall:
276 .long __{name}_init - .
277 .previous
278 \"#
279 );
280
281 #[cfg(not(MODULE))]
282 #[doc(hidden)]
283 #[no_mangle]
284 pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{
285 // SAFETY: This function is inaccessible to the outside due to the double
286 // module wrapping it. It is called exactly once by the C side via its
287 // placement above in the initcall section.
288 unsafe {{ __init() }}
289 }}
290
291 #[cfg(not(MODULE))]
292 #[doc(hidden)]
293 #[no_mangle]
294 pub extern \"C\" fn __{name}_exit() {{
295 // SAFETY:
296 // - This function is inaccessible to the outside due to the double
297 // module wrapping it. It is called exactly once by the C side via its
298 // unique name,
299 // - furthermore it is only called after `__{name}_init` has returned `0`
300 // (which delegates to `__init`).
301 unsafe {{ __exit() }}
302 }}
303
304 /// # Safety
305 ///
306 /// This function must only be called once.
307 unsafe fn __init() -> core::ffi::c_int {{
308 match <{type_} as kernel::Module>::init(&super::super::THIS_MODULE) {{
309 Ok(m) => {{
310 // SAFETY: No data race, since `__MOD` can only be accessed by this
311 // module and there only `__init` and `__exit` access it. These
312 // functions are only called once and `__exit` cannot be called
313 // before or during `__init`.
314 unsafe {{
315 __MOD = Some(m);
316 }}
317 return 0;
318 }}
319 Err(e) => {{
320 return e.to_errno();
321 }}
322 }}
323 }}
324
325 /// # Safety
326 ///
327 /// This function must
328 /// - only be called once,
329 /// - be called after `__init` has been called and returned `0`.
330 unsafe fn __exit() {{
331 // SAFETY: No data race, since `__MOD` can only be accessed by this module
332 // and there only `__init` and `__exit` access it. These functions are only
333 // called once and `__init` was already called.
334 unsafe {{
335 // Invokes `drop()` on `__MOD`, which should be used for cleanup.
336 __MOD = None;
337 }}
338 }}
339
340 {modinfo}
341 }}
342 }}
343 ",
344 type_ = info.type_,
345 name = info.name,
346 modinfo = modinfo.buffer,
347 initcall_section = ".initcall6.init"
348 )
349 .parse()
350 .expect("Error parsing formatted string into token stream.")
351 }
352