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 } 101 102 impl ModuleInfo { 103 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 } 170 171 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 kernel::ThisModule::from_ptr(&kernel::bindings::__this_module as *const _ as *mut _) 207 }}; 208 #[cfg(not(MODULE))] 209 static THIS_MODULE: kernel::ThisModule = unsafe {{ 210 kernel::ThisModule::from_ptr(core::ptr::null_mut()) 211 }}; 212 213 // Double nested modules, since then nobody can access the public items inside. 214 mod __module_init {{ 215 mod __module_init {{ 216 use super::super::{type_}; 217 218 /// The \"Rust loadable module\" mark. 219 // 220 // This may be best done another way later on, e.g. as a new modinfo 221 // key or a new section. For the moment, keep it simple. 222 #[cfg(MODULE)] 223 #[doc(hidden)] 224 #[used] 225 static __IS_RUST_MODULE: () = (); 226 227 static mut __MOD: Option<{type_}> = None; 228 229 // Loadable modules need to export the `{{init,cleanup}}_module` identifiers. 230 /// # Safety 231 /// 232 /// This function must not be called after module initialization, because it may be 233 /// freed after that completes. 234 #[cfg(MODULE)] 235 #[doc(hidden)] 236 #[no_mangle] 237 #[link_section = \".init.text\"] 238 pub unsafe extern \"C\" fn init_module() -> core::ffi::c_int {{ 239 // SAFETY: This function is inaccessible to the outside due to the double 240 // module wrapping it. It is called exactly once by the C side via its 241 // unique name. 242 unsafe {{ __init() }} 243 }} 244 245 #[cfg(MODULE)] 246 #[doc(hidden)] 247 #[no_mangle] 248 pub extern \"C\" fn cleanup_module() {{ 249 // SAFETY: 250 // - This function is inaccessible to the outside due to the double 251 // module wrapping it. It is called exactly once by the C side via its 252 // unique name, 253 // - furthermore it is only called after `init_module` has returned `0` 254 // (which delegates to `__init`). 255 unsafe {{ __exit() }} 256 }} 257 258 // Built-in modules are initialized through an initcall pointer 259 // and the identifiers need to be unique. 260 #[cfg(not(MODULE))] 261 #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))] 262 #[doc(hidden)] 263 #[link_section = \"{initcall_section}\"] 264 #[used] 265 pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init; 266 267 #[cfg(not(MODULE))] 268 #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)] 269 core::arch::global_asm!( 270 r#\".section \"{initcall_section}\", \"a\" 271 __{name}_initcall: 272 .long __{name}_init - . 273 .previous 274 \"# 275 ); 276 277 #[cfg(not(MODULE))] 278 #[doc(hidden)] 279 #[no_mangle] 280 pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{ 281 // SAFETY: This function is inaccessible to the outside due to the double 282 // module wrapping it. It is called exactly once by the C side via its 283 // placement above in the initcall section. 284 unsafe {{ __init() }} 285 }} 286 287 #[cfg(not(MODULE))] 288 #[doc(hidden)] 289 #[no_mangle] 290 pub extern \"C\" fn __{name}_exit() {{ 291 // SAFETY: 292 // - This function is inaccessible to the outside due to the double 293 // module wrapping it. It is called exactly once by the C side via its 294 // unique name, 295 // - furthermore it is only called after `__{name}_init` has returned `0` 296 // (which delegates to `__init`). 297 unsafe {{ __exit() }} 298 }} 299 300 /// # Safety 301 /// 302 /// This function must only be called once. 303 unsafe fn __init() -> core::ffi::c_int {{ 304 match <{type_} as kernel::Module>::init(&super::super::THIS_MODULE) {{ 305 Ok(m) => {{ 306 // SAFETY: No data race, since `__MOD` can only be accessed by this 307 // module and there only `__init` and `__exit` access it. These 308 // functions are only called once and `__exit` cannot be called 309 // before or during `__init`. 310 unsafe {{ 311 __MOD = Some(m); 312 }} 313 return 0; 314 }} 315 Err(e) => {{ 316 return e.to_errno(); 317 }} 318 }} 319 }} 320 321 /// # Safety 322 /// 323 /// This function must 324 /// - only be called once, 325 /// - be called after `__init` has been called and returned `0`. 326 unsafe fn __exit() {{ 327 // SAFETY: No data race, since `__MOD` can only be accessed by this module 328 // and there only `__init` and `__exit` access it. These functions are only 329 // called once and `__init` was already called. 330 unsafe {{ 331 // Invokes `drop()` on `__MOD`, which should be used for cleanup. 332 __MOD = None; 333 }} 334 }} 335 336 {modinfo} 337 }} 338 }} 339 ", 340 type_ = info.type_, 341 name = info.name, 342 modinfo = modinfo.buffer, 343 initcall_section = ".initcall6.init" 344 ) 345 .parse() 346 .expect("Error parsing formatted string into token stream.") 347 } 348