macros/
module.rs

1// SPDX-License-Identifier: GPL-2.0
2
3use crate::helpers::*;
4use proc_macro::{token_stream, Delimiter, Literal, TokenStream, TokenTree};
5use std::fmt::Write;
6
7fn 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
25struct ModInfoBuilder<'a> {
26    module: &'a str,
27    counter: usize,
28    buffer: String,
29    param_buffer: String,
30}
31
32impl<'a> ModInfoBuilder<'a> {
33    fn new(module: &'a str) -> Self {
34        ModInfoBuilder {
35            module,
36            counter: 0,
37            buffer: String::new(),
38            param_buffer: String::new(),
39        }
40    }
41
42    fn emit_base(&mut self, field: &str, content: &str, builtin: bool, param: bool) {
43        let string = if builtin {
44            // Built-in modules prefix their modinfo strings by `module.`.
45            format!(
46                "{module}.{field}={content}\0",
47                module = self.module,
48                field = field,
49                content = content
50            )
51        } else {
52            // Loadable modules' modinfo strings go as-is.
53            format!("{field}={content}\0")
54        };
55
56        let buffer = if param {
57            &mut self.param_buffer
58        } else {
59            &mut self.buffer
60        };
61
62        write!(
63            buffer,
64            "
65                {cfg}
66                #[doc(hidden)]
67                #[cfg_attr(not(target_os = \"macos\"), link_section = \".modinfo\")]
68                #[used(compiler)]
69                pub static __{module}_{counter}: [u8; {length}] = *{string};
70            ",
71            cfg = if builtin {
72                "#[cfg(not(MODULE))]"
73            } else {
74                "#[cfg(MODULE)]"
75            },
76            module = self.module.to_uppercase(),
77            counter = self.counter,
78            length = string.len(),
79            string = Literal::byte_string(string.as_bytes()),
80        )
81        .unwrap();
82
83        self.counter += 1;
84    }
85
86    fn emit_only_builtin(&mut self, field: &str, content: &str, param: bool) {
87        self.emit_base(field, content, true, param)
88    }
89
90    fn emit_only_loadable(&mut self, field: &str, content: &str, param: bool) {
91        self.emit_base(field, content, false, param)
92    }
93
94    fn emit(&mut self, field: &str, content: &str) {
95        self.emit_internal(field, content, false);
96    }
97
98    fn emit_internal(&mut self, field: &str, content: &str, param: bool) {
99        self.emit_only_builtin(field, content, param);
100        self.emit_only_loadable(field, content, param);
101    }
102
103    fn emit_param(&mut self, field: &str, param: &str, content: &str) {
104        let content = format!("{param}:{content}", param = param, content = content);
105        self.emit_internal(field, &content, true);
106    }
107
108    fn emit_params(&mut self, info: &ModuleInfo) {
109        let Some(params) = &info.params else {
110            return;
111        };
112
113        for param in params {
114            let ops = param_ops_path(&param.ptype);
115
116            // Note: The spelling of these fields is dictated by the user space
117            // tool `modinfo`.
118            self.emit_param("parmtype", &param.name, &param.ptype);
119            self.emit_param("parm", &param.name, &param.description);
120
121            write!(
122                self.param_buffer,
123                "
124                pub(crate) static {param_name}:
125                    ::kernel::module_param::ModuleParamAccess<{param_type}> =
126                        ::kernel::module_param::ModuleParamAccess::new({param_default});
127
128                const _: () = {{
129                    #[link_section = \"__param\"]
130                    #[used]
131                    static __{module_name}_{param_name}_struct:
132                        ::kernel::module_param::KernelParam =
133                        ::kernel::module_param::KernelParam::new(
134                            ::kernel::bindings::kernel_param {{
135                                name: if ::core::cfg!(MODULE) {{
136                                    ::kernel::c_str!(\"{param_name}\").to_bytes_with_nul()
137                                }} else {{
138                                    ::kernel::c_str!(\"{module_name}.{param_name}\")
139                                        .to_bytes_with_nul()
140                                }}.as_ptr(),
141                                // SAFETY: `__this_module` is constructed by the kernel at load
142                                // time and will not be freed until the module is unloaded.
143                                #[cfg(MODULE)]
144                                mod_: unsafe {{
145                                    core::ptr::from_ref(&::kernel::bindings::__this_module)
146                                        .cast_mut()
147                                }},
148                                #[cfg(not(MODULE))]
149                                mod_: ::core::ptr::null_mut(),
150                                ops: core::ptr::from_ref(&{ops}),
151                                perm: 0, // Will not appear in sysfs
152                                level: -1,
153                                flags: 0,
154                                __bindgen_anon_1: ::kernel::bindings::kernel_param__bindgen_ty_1 {{
155                                    arg: {param_name}.as_void_ptr()
156                                }},
157                            }}
158                        );
159                }};
160                ",
161                module_name = info.name,
162                param_type = param.ptype,
163                param_default = param.default,
164                param_name = param.name,
165                ops = ops,
166            )
167            .unwrap();
168        }
169    }
170}
171
172fn param_ops_path(param_type: &str) -> &'static str {
173    match param_type {
174        "i8" => "::kernel::module_param::PARAM_OPS_I8",
175        "u8" => "::kernel::module_param::PARAM_OPS_U8",
176        "i16" => "::kernel::module_param::PARAM_OPS_I16",
177        "u16" => "::kernel::module_param::PARAM_OPS_U16",
178        "i32" => "::kernel::module_param::PARAM_OPS_I32",
179        "u32" => "::kernel::module_param::PARAM_OPS_U32",
180        "i64" => "::kernel::module_param::PARAM_OPS_I64",
181        "u64" => "::kernel::module_param::PARAM_OPS_U64",
182        "isize" => "::kernel::module_param::PARAM_OPS_ISIZE",
183        "usize" => "::kernel::module_param::PARAM_OPS_USIZE",
184        t => panic!("Unsupported parameter type {}", t),
185    }
186}
187
188fn expect_param_default(param_it: &mut token_stream::IntoIter) -> String {
189    assert_eq!(expect_ident(param_it), "default");
190    assert_eq!(expect_punct(param_it), ':');
191    let sign = try_sign(param_it);
192    let default = try_literal(param_it).expect("Expected default param value");
193    assert_eq!(expect_punct(param_it), ',');
194    let mut value = sign.map(String::from).unwrap_or_default();
195    value.push_str(&default);
196    value
197}
198
199#[derive(Debug, Default)]
200struct ModuleInfo {
201    type_: String,
202    license: String,
203    name: String,
204    authors: Option<Vec<String>>,
205    description: Option<String>,
206    alias: Option<Vec<String>>,
207    firmware: Option<Vec<String>>,
208    imports_ns: Option<Vec<String>>,
209    params: Option<Vec<Parameter>>,
210}
211
212#[derive(Debug)]
213struct Parameter {
214    name: String,
215    ptype: String,
216    default: String,
217    description: String,
218}
219
220fn expect_params(it: &mut token_stream::IntoIter) -> Vec<Parameter> {
221    let params = expect_group(it);
222    assert_eq!(params.delimiter(), Delimiter::Brace);
223    let mut it = params.stream().into_iter();
224    let mut parsed = Vec::new();
225
226    loop {
227        let param_name = match it.next() {
228            Some(TokenTree::Ident(ident)) => ident.to_string(),
229            Some(_) => panic!("Expected Ident or end"),
230            None => break,
231        };
232
233        assert_eq!(expect_punct(&mut it), ':');
234        let param_type = expect_ident(&mut it);
235        let group = expect_group(&mut it);
236        assert_eq!(group.delimiter(), Delimiter::Brace);
237        assert_eq!(expect_punct(&mut it), ',');
238
239        let mut param_it = group.stream().into_iter();
240        let param_default = expect_param_default(&mut param_it);
241        let param_description = expect_string_field(&mut param_it, "description");
242        expect_end(&mut param_it);
243
244        parsed.push(Parameter {
245            name: param_name,
246            ptype: param_type,
247            default: param_default,
248            description: param_description,
249        })
250    }
251
252    parsed
253}
254
255impl ModuleInfo {
256    fn parse(it: &mut token_stream::IntoIter) -> Self {
257        let mut info = ModuleInfo::default();
258
259        const EXPECTED_KEYS: &[&str] = &[
260            "type",
261            "name",
262            "authors",
263            "description",
264            "license",
265            "alias",
266            "firmware",
267            "imports_ns",
268            "params",
269        ];
270        const REQUIRED_KEYS: &[&str] = &["type", "name", "license"];
271        let mut seen_keys = Vec::new();
272
273        loop {
274            let key = match it.next() {
275                Some(TokenTree::Ident(ident)) => ident.to_string(),
276                Some(_) => panic!("Expected Ident or end"),
277                None => break,
278            };
279
280            if seen_keys.contains(&key) {
281                panic!("Duplicated key \"{key}\". Keys can only be specified once.");
282            }
283
284            assert_eq!(expect_punct(it), ':');
285
286            match key.as_str() {
287                "type" => info.type_ = expect_ident(it),
288                "name" => info.name = expect_string_ascii(it),
289                "authors" => info.authors = Some(expect_string_array(it)),
290                "description" => info.description = Some(expect_string(it)),
291                "license" => info.license = expect_string_ascii(it),
292                "alias" => info.alias = Some(expect_string_array(it)),
293                "firmware" => info.firmware = Some(expect_string_array(it)),
294                "imports_ns" => info.imports_ns = Some(expect_string_array(it)),
295                "params" => info.params = Some(expect_params(it)),
296                _ => panic!("Unknown key \"{key}\". Valid keys are: {EXPECTED_KEYS:?}."),
297            }
298
299            assert_eq!(expect_punct(it), ',');
300
301            seen_keys.push(key);
302        }
303
304        expect_end(it);
305
306        for key in REQUIRED_KEYS {
307            if !seen_keys.iter().any(|e| e == key) {
308                panic!("Missing required key \"{key}\".");
309            }
310        }
311
312        let mut ordered_keys: Vec<&str> = Vec::new();
313        for key in EXPECTED_KEYS {
314            if seen_keys.iter().any(|e| e == key) {
315                ordered_keys.push(key);
316            }
317        }
318
319        if seen_keys != ordered_keys {
320            panic!("Keys are not ordered as expected. Order them like: {ordered_keys:?}.");
321        }
322
323        info
324    }
325}
326
327pub(crate) fn module(ts: TokenStream) -> TokenStream {
328    let mut it = ts.into_iter();
329
330    let info = ModuleInfo::parse(&mut it);
331
332    // Rust does not allow hyphens in identifiers, use underscore instead.
333    let ident = info.name.replace('-', "_");
334    let mut modinfo = ModInfoBuilder::new(ident.as_ref());
335    if let Some(authors) = &info.authors {
336        for author in authors {
337            modinfo.emit("author", author);
338        }
339    }
340    if let Some(description) = &info.description {
341        modinfo.emit("description", description);
342    }
343    modinfo.emit("license", &info.license);
344    if let Some(aliases) = &info.alias {
345        for alias in aliases {
346            modinfo.emit("alias", alias);
347        }
348    }
349    if let Some(firmware) = &info.firmware {
350        for fw in firmware {
351            modinfo.emit("firmware", fw);
352        }
353    }
354    if let Some(imports) = &info.imports_ns {
355        for ns in imports {
356            modinfo.emit("import_ns", ns);
357        }
358    }
359
360    // Built-in modules also export the `file` modinfo string.
361    let file =
362        std::env::var("RUST_MODFILE").expect("Unable to fetch RUST_MODFILE environmental variable");
363    modinfo.emit_only_builtin("file", &file, false);
364
365    modinfo.emit_params(&info);
366
367    format!(
368        "
369            /// The module name.
370            ///
371            /// Used by the printing macros, e.g. [`info!`].
372            const __LOG_PREFIX: &[u8] = b\"{name}\\0\";
373
374            // SAFETY: `__this_module` is constructed by the kernel at load time and will not be
375            // freed until the module is unloaded.
376            #[cfg(MODULE)]
377            static THIS_MODULE: ::kernel::ThisModule = unsafe {{
378                extern \"C\" {{
379                    static __this_module: ::kernel::types::Opaque<::kernel::bindings::module>;
380                }}
381
382                ::kernel::ThisModule::from_ptr(__this_module.get())
383            }};
384            #[cfg(not(MODULE))]
385            static THIS_MODULE: ::kernel::ThisModule = unsafe {{
386                ::kernel::ThisModule::from_ptr(::core::ptr::null_mut())
387            }};
388
389            /// The `LocalModule` type is the type of the module created by `module!`,
390            /// `module_pci_driver!`, `module_platform_driver!`, etc.
391            type LocalModule = {type_};
392
393            impl ::kernel::ModuleMetadata for {type_} {{
394                const NAME: &'static ::kernel::str::CStr = c\"{name}\";
395            }}
396
397            // Double nested modules, since then nobody can access the public items inside.
398            mod __module_init {{
399                mod __module_init {{
400                    use super::super::{type_};
401                    use pin_init::PinInit;
402
403                    /// The \"Rust loadable module\" mark.
404                    //
405                    // This may be best done another way later on, e.g. as a new modinfo
406                    // key or a new section. For the moment, keep it simple.
407                    #[cfg(MODULE)]
408                    #[doc(hidden)]
409                    #[used(compiler)]
410                    static __IS_RUST_MODULE: () = ();
411
412                    static mut __MOD: ::core::mem::MaybeUninit<{type_}> =
413                        ::core::mem::MaybeUninit::uninit();
414
415                    // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
416                    /// # Safety
417                    ///
418                    /// This function must not be called after module initialization, because it may be
419                    /// freed after that completes.
420                    #[cfg(MODULE)]
421                    #[doc(hidden)]
422                    #[no_mangle]
423                    #[link_section = \".init.text\"]
424                    pub unsafe extern \"C\" fn init_module() -> ::kernel::ffi::c_int {{
425                        // SAFETY: This function is inaccessible to the outside due to the double
426                        // module wrapping it. It is called exactly once by the C side via its
427                        // unique name.
428                        unsafe {{ __init() }}
429                    }}
430
431                    #[cfg(MODULE)]
432                    #[doc(hidden)]
433                    #[used(compiler)]
434                    #[link_section = \".init.data\"]
435                    static __UNIQUE_ID___addressable_init_module: unsafe extern \"C\" fn() -> i32 = init_module;
436
437                    #[cfg(MODULE)]
438                    #[doc(hidden)]
439                    #[no_mangle]
440                    #[link_section = \".exit.text\"]
441                    pub extern \"C\" fn cleanup_module() {{
442                        // SAFETY:
443                        // - This function is inaccessible to the outside due to the double
444                        //   module wrapping it. It is called exactly once by the C side via its
445                        //   unique name,
446                        // - furthermore it is only called after `init_module` has returned `0`
447                        //   (which delegates to `__init`).
448                        unsafe {{ __exit() }}
449                    }}
450
451                    #[cfg(MODULE)]
452                    #[doc(hidden)]
453                    #[used(compiler)]
454                    #[link_section = \".exit.data\"]
455                    static __UNIQUE_ID___addressable_cleanup_module: extern \"C\" fn() = cleanup_module;
456
457                    // Built-in modules are initialized through an initcall pointer
458                    // and the identifiers need to be unique.
459                    #[cfg(not(MODULE))]
460                    #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
461                    #[doc(hidden)]
462                    #[link_section = \"{initcall_section}\"]
463                    #[used(compiler)]
464                    pub static __{ident}_initcall: extern \"C\" fn() ->
465                        ::kernel::ffi::c_int = __{ident}_init;
466
467                    #[cfg(not(MODULE))]
468                    #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
469                    ::core::arch::global_asm!(
470                        r#\".section \"{initcall_section}\", \"a\"
471                        __{ident}_initcall:
472                            .long   __{ident}_init - .
473                            .previous
474                        \"#
475                    );
476
477                    #[cfg(not(MODULE))]
478                    #[doc(hidden)]
479                    #[no_mangle]
480                    pub extern \"C\" fn __{ident}_init() -> ::kernel::ffi::c_int {{
481                        // SAFETY: This function is inaccessible to the outside due to the double
482                        // module wrapping it. It is called exactly once by the C side via its
483                        // placement above in the initcall section.
484                        unsafe {{ __init() }}
485                    }}
486
487                    #[cfg(not(MODULE))]
488                    #[doc(hidden)]
489                    #[no_mangle]
490                    pub extern \"C\" fn __{ident}_exit() {{
491                        // SAFETY:
492                        // - This function is inaccessible to the outside due to the double
493                        //   module wrapping it. It is called exactly once by the C side via its
494                        //   unique name,
495                        // - furthermore it is only called after `__{ident}_init` has
496                        //   returned `0` (which delegates to `__init`).
497                        unsafe {{ __exit() }}
498                    }}
499
500                    /// # Safety
501                    ///
502                    /// This function must only be called once.
503                    unsafe fn __init() -> ::kernel::ffi::c_int {{
504                        let initer =
505                            <{type_} as ::kernel::InPlaceModule>::init(&super::super::THIS_MODULE);
506                        // SAFETY: No data race, since `__MOD` can only be accessed by this module
507                        // and there only `__init` and `__exit` access it. These functions are only
508                        // called once and `__exit` cannot be called before or during `__init`.
509                        match unsafe {{ initer.__pinned_init(__MOD.as_mut_ptr()) }} {{
510                            Ok(m) => 0,
511                            Err(e) => e.to_errno(),
512                        }}
513                    }}
514
515                    /// # Safety
516                    ///
517                    /// This function must
518                    /// - only be called once,
519                    /// - be called after `__init` has been called and returned `0`.
520                    unsafe fn __exit() {{
521                        // SAFETY: No data race, since `__MOD` can only be accessed by this module
522                        // and there only `__init` and `__exit` access it. These functions are only
523                        // called once and `__init` was already called.
524                        unsafe {{
525                            // Invokes `drop()` on `__MOD`, which should be used for cleanup.
526                            __MOD.assume_init_drop();
527                        }}
528                    }}
529                    {modinfo}
530                }}
531            }}
532            mod module_parameters {{
533                {params}
534            }}
535        ",
536        type_ = info.type_,
537        name = info.name,
538        ident = ident,
539        modinfo = modinfo.buffer,
540        params = modinfo.param_buffer,
541        initcall_section = ".initcall6.init"
542    )
543    .parse()
544    .expect("Error parsing formatted string into token stream.")
545}
macros/module.rs

macros/
module.rs
