1 use core::{ 2 hint::spin_loop, 3 sync::atomic::{AtomicBool, Ordering}, 4 }; 5 6 use alloc::{ 7 boxed::Box, 8 collections::LinkedList, 9 string::{String, ToString}, 10 sync::{Arc, Weak}, 11 }; 12 use atomic_enum::atomic_enum; 13 use system_error::SystemError; 14 15 use crate::{ 16 arch::{sched::sched, CurrentIrqArch}, 17 exception::{irqdesc::IrqAction, InterruptArch}, 18 init::initial_kthread::initial_kernel_thread, 19 kdebug, kinfo, 20 libs::{once::Once, spinlock::SpinLock}, 21 process::{ProcessManager, ProcessState}, 22 }; 23 24 use super::{fork::CloneFlags, Pid, ProcessControlBlock, ProcessFlags}; 25 26 /// 内核线程的创建任务列表 27 static KTHREAD_CREATE_LIST: SpinLock<LinkedList<Arc<KernelThreadCreateInfo>>> = 28 SpinLock::new(LinkedList::new()); 29 30 static mut KTHREAD_DAEMON_PCB: Option<Arc<ProcessControlBlock>> = None; 31 32 #[derive(Debug)] 33 pub enum WorkerPrivate { 34 KernelThread(KernelThreadPcbPrivate), 35 } 36 37 #[allow(dead_code)] 38 impl WorkerPrivate { 39 pub fn kernel_thread(&self) -> Option<&KernelThreadPcbPrivate> { 40 match self { 41 Self::KernelThread(x) => Some(x), 42 } 43 } 44 45 pub fn kernel_thread_mut(&mut self) -> Option<&mut KernelThreadPcbPrivate> { 46 match self { 47 Self::KernelThread(x) => Some(x), 48 } 49 } 50 } 51 52 bitflags! { 53 pub struct KernelThreadFlags: u32 { 54 const IS_PER_CPU = 1 << 0; 55 const SHOULD_STOP = 1 << 1; 56 const SHOULD_PARK = 1 << 2; 57 } 58 } 59 60 #[derive(Debug)] 61 pub struct KernelThreadPcbPrivate { 62 flags: KernelThreadFlags, 63 } 64 65 #[allow(dead_code)] 66 impl KernelThreadPcbPrivate { 67 pub fn new() -> Self { 68 Self { 69 flags: KernelThreadFlags::empty(), 70 } 71 } 72 73 pub fn flags(&self) -> &KernelThreadFlags { 74 &self.flags 75 } 76 77 pub fn flags_mut(&mut self) -> &mut KernelThreadFlags { 78 &mut self.flags 79 } 80 } 81 82 /// 内核线程的闭包，参数必须与闭包的参数一致，返回值必须是i32 83 /// 84 /// 元组的第一个元素是闭包，第二个元素是闭包的参数对象 85 /// 86 /// 对于非原始类型的参数，需要使用Box包装 87 #[allow(dead_code)] 88 pub enum KernelThreadClosure { 89 UsizeClosure((Box<dyn Fn(usize) -> i32 + Send + Sync>, usize)), 90 StaticUsizeClosure((&'static dyn Fn(usize) -> i32, usize)), 91 EmptyClosure((Box<dyn Fn() -> i32 + Send + Sync>, ())), 92 StaticEmptyClosure((&'static dyn Fn() -> i32, ())), 93 IrqThread( 94 ( 95 &'static dyn Fn(Arc<IrqAction>) -> Result<(), SystemError>, 96 Arc<IrqAction>, 97 ), 98 ), 99 // 添加其他类型入参的闭包，返回值必须是i32 100 } 101 102 unsafe impl Send for KernelThreadClosure {} 103 unsafe impl Sync for KernelThreadClosure {} 104 105 impl KernelThreadClosure { 106 pub fn run(self) -> i32 { 107 match self { 108 Self::UsizeClosure((func, arg)) => func(arg), 109 Self::EmptyClosure((func, _arg)) => func(), 110 Self::StaticUsizeClosure((func, arg)) => func(arg), 111 Self::StaticEmptyClosure((func, _arg)) => func(), 112 Self::IrqThread((func, arg)) => { 113 func(arg).map(|_| 0).unwrap_or_else(|e| e.to_posix_errno()) 114 } 115 } 116 } 117 } 118 119 pub struct KernelThreadCreateInfo { 120 /// 内核线程的入口函数、传入参数 121 closure: SpinLock<Option<Box<KernelThreadClosure>>>, 122 /// 内核线程的名字 123 name: String, 124 /// 是否已经完成创建 todo:使用comletion机制优化这里 125 created: AtomicKernelThreadCreateStatus, 126 result_pcb: SpinLock<Option<Arc<ProcessControlBlock>>>, 127 /// 不安全的Arc引用计数，当内核线程创建失败时，需要减少这个计数 128 has_unsafe_arc_instance: AtomicBool, 129 self_ref: Weak<Self>, 130 /// 如果该值为true在进入bootstrap stage2之后，就会进入睡眠状态 131 to_mark_sleep: AtomicBool, 132 } 133 134 #[atomic_enum] 135 #[derive(PartialEq)] 136 pub enum KernelThreadCreateStatus { 137 Created, 138 NotCreated, 139 ErrorOccured, 140 } 141 142 #[allow(dead_code)] 143 impl KernelThreadCreateInfo { 144 pub fn new(func: KernelThreadClosure, name: String) -> Arc<Self> { 145 let result = Arc::new(Self { 146 closure: SpinLock::new(Some(Box::new(func))), 147 name, 148 created: AtomicKernelThreadCreateStatus::new(KernelThreadCreateStatus::NotCreated), 149 result_pcb: SpinLock::new(None), 150 has_unsafe_arc_instance: AtomicBool::new(false), 151 self_ref: Weak::new(), 152 to_mark_sleep: AtomicBool::new(true), 153 }); 154 let tmp = result.clone(); 155 unsafe { 156 let tmp = Arc::into_raw(tmp) as *mut Self; 157 (*tmp).self_ref = Arc::downgrade(&result); 158 Arc::from_raw(tmp); 159 } 160 161 return result; 162 } 163 164 /// 创建者调用这函数，等待创建完成后，获取创建结果 165 /// 166 /// ## 返回值 167 /// 168 /// - Some(Arc<ProcessControlBlock>) 创建成功，返回新创建的内核线程的PCB 169 /// - None 创建失败 170 pub fn poll_result(&self) -> Option<Arc<ProcessControlBlock>> { 171 loop { 172 match self.created.load(Ordering::SeqCst) { 173 KernelThreadCreateStatus::Created => { 174 return self.result_pcb.lock().take(); 175 } 176 KernelThreadCreateStatus::NotCreated => { 177 spin_loop(); 178 } 179 KernelThreadCreateStatus::ErrorOccured => { 180 // 创建失败，减少不安全的Arc引用计数 181 let to_delete = self.has_unsafe_arc_instance.swap(false, Ordering::SeqCst); 182 if to_delete { 183 let self_ref = self.self_ref.upgrade().unwrap(); 184 unsafe { Arc::decrement_strong_count(&self_ref) }; 185 } 186 return None; 187 } 188 } 189 } 190 } 191 192 pub fn take_closure(&self) -> Option<Box<KernelThreadClosure>> { 193 return self.closure.lock().take(); 194 } 195 196 pub fn name(&self) -> &String { 197 &self.name 198 } 199 200 pub unsafe fn set_create_ok(&self, pcb: Arc<ProcessControlBlock>) { 201 // todo: 使用completion机制优化这里 202 self.result_pcb.lock().replace(pcb); 203 self.created 204 .store(KernelThreadCreateStatus::Created, Ordering::SeqCst); 205 } 206 207 /// 生成一个不安全的Arc指针（用于创建内核线程时传递参数） 208 pub fn generate_unsafe_arc_ptr(self: Arc<Self>) -> *const Self { 209 assert!( 210 self.has_unsafe_arc_instance 211 .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst) 212 .is_ok(), 213 "Cannot generate unsafe arc ptr when there is already one." 214 ); 215 let ptr = Arc::into_raw(self); 216 return ptr; 217 } 218 219 pub unsafe fn parse_unsafe_arc_ptr(ptr: *const Self) -> Arc<Self> { 220 let arc = Arc::from_raw(ptr); 221 assert!( 222 arc.has_unsafe_arc_instance 223 .compare_exchange(true, false, Ordering::SeqCst, Ordering::SeqCst) 224 .is_ok(), 225 "Cannot parse unsafe arc ptr when there is no one." 226 ); 227 assert!(Arc::strong_count(&arc) > 0); 228 return arc; 229 } 230 231 /// 设置是否在进入bootstrap stage2之后，就进入睡眠状态 232 /// 233 /// ## 参数 234 /// 235 /// - to_mark_sleep: 是否在进入bootstrap stage2之后，就进入睡眠状态 236 /// 237 /// ## 返回值 238 /// 如果已经创建完成，返回EINVAL 239 pub fn set_to_mark_sleep(&self, to_mark_sleep: bool) -> Result<(), SystemError> { 240 let result_guard = self.result_pcb.lock(); 241 if result_guard.is_some() { 242 // 已经创建完成，不需要设置 243 return Err(SystemError::EINVAL); 244 } 245 self.to_mark_sleep.store(to_mark_sleep, Ordering::SeqCst); 246 return Ok(()); 247 } 248 249 pub fn to_mark_sleep(&self) -> bool { 250 self.to_mark_sleep.load(Ordering::SeqCst) 251 } 252 } 253 254 pub struct KernelThreadMechanism; 255 256 impl KernelThreadMechanism { 257 pub fn init_stage1() { 258 assert!(ProcessManager::current_pcb().pid() == Pid::new(0)); 259 kinfo!("Initializing kernel thread mechanism stage1..."); 260 261 // 初始化第一个内核线程 262 263 let create_info = KernelThreadCreateInfo::new( 264 KernelThreadClosure::EmptyClosure((Box::new(initial_kernel_thread), ())), 265 "init".to_string(), 266 ); 267 268 let irq_guard: crate::exception::IrqFlagsGuard = 269 unsafe { CurrentIrqArch::save_and_disable_irq() }; 270 // 由于当前是pid=0的idle进程,而__inner_create要求当前是kthread,所以先临时设置为kthread 271 ProcessManager::current_pcb() 272 .flags 273 .get_mut() 274 .insert(ProcessFlags::KTHREAD); 275 create_info 276 .set_to_mark_sleep(false) 277 .expect("Failed to set to_mark_sleep"); 278 279 KernelThreadMechanism::__inner_create( 280 &create_info, 281 CloneFlags::CLONE_VM | CloneFlags::CLONE_SIGNAL, 282 ) 283 .unwrap_or_else(|e| panic!("Failed to create initial kernel thread, error: {:?}", e)); 284 285 ProcessManager::current_pcb() 286 .flags 287 .get_mut() 288 .remove(ProcessFlags::KTHREAD); 289 290 drop(irq_guard); 291 kinfo!("Initializing kernel thread mechanism stage1 complete"); 292 } 293 294 pub fn init_stage2() { 295 assert!(ProcessManager::current_pcb() 296 .flags() 297 .contains(ProcessFlags::KTHREAD)); 298 static INIT: Once = Once::new(); 299 INIT.call_once(|| { 300 kinfo!("Initializing kernel thread mechanism stage2..."); 301 // 初始化kthreadd 302 let closure = KernelThreadClosure::EmptyClosure((Box::new(Self::kthread_daemon), ())); 303 let info = KernelThreadCreateInfo::new(closure, "kthreadd".to_string()); 304 let kthreadd_pid: Pid = Self::__inner_create( 305 &info, 306 CloneFlags::CLONE_VM | CloneFlags::CLONE_FS | CloneFlags::CLONE_SIGNAL, 307 ) 308 .expect("Failed to create kthread daemon"); 309 let pcb = ProcessManager::find(kthreadd_pid).unwrap(); 310 ProcessManager::wakeup(&pcb).expect("Failed to wakeup kthread daemon"); 311 unsafe { 312 KTHREAD_DAEMON_PCB.replace(pcb); 313 } 314 kinfo!("Initializing kernel thread mechanism stage2 complete"); 315 }); 316 } 317 318 /// 创建一个新的内核线程 319 /// 320 /// ## 参数 321 /// 322 /// - func: 内核线程的入口函数、传入参数 323 /// - name: 内核线程的名字 324 /// 325 /// ## 返回值 326 /// 327 /// - Some(Arc<ProcessControlBlock>) 创建成功，返回新创建的内核线程的PCB 328 #[allow(dead_code)] 329 pub fn create(func: KernelThreadClosure, name: String) -> Option<Arc<ProcessControlBlock>> { 330 let info = KernelThreadCreateInfo::new(func, name); 331 while unsafe { KTHREAD_DAEMON_PCB.is_none() } { 332 // 等待kthreadd启动 333 spin_loop() 334 } 335 KTHREAD_CREATE_LIST.lock().push_back(info.clone()); 336 ProcessManager::wakeup(unsafe { KTHREAD_DAEMON_PCB.as_ref().unwrap() }) 337 .expect("Failed to wakeup kthread daemon"); 338 return info.poll_result(); 339 } 340 341 /// 创建并运行一个新的内核线程 342 /// 343 /// ## 参数 344 /// 345 /// - func: 内核线程的入口函数、传入参数 346 /// - name: 内核线程的名字 347 /// 348 /// ## 返回值 349 /// 350 /// - Some(Arc<ProcessControlBlock>) 创建成功，返回新创建的内核线程的PCB 351 #[allow(dead_code)] 352 pub fn create_and_run( 353 func: KernelThreadClosure, 354 name: String, 355 ) -> Option<Arc<ProcessControlBlock>> { 356 let pcb = Self::create(func, name)?; 357 ProcessManager::wakeup(&pcb) 358 .expect(format!("Failed to wakeup kthread: {:?}", pcb.pid()).as_str()); 359 return Some(pcb); 360 } 361 362 /// 停止一个内核线程 363 /// 364 /// 如果目标内核线程的数据检查失败，会panic 365 /// 366 /// ## 返回值 367 /// 368 /// - Ok(i32) 目标内核线程的退出码 369 #[allow(dead_code)] 370 pub fn stop(pcb: &Arc<ProcessControlBlock>) -> Result<usize, SystemError> { 371 if !pcb.flags().contains(ProcessFlags::KTHREAD) { 372 panic!("Cannt stop a non-kthread process"); 373 } 374 375 let mut worker_private = pcb.worker_private(); 376 assert!( 377 worker_private.is_some(), 378 "kthread stop: worker_private is none, pid: {:?}", 379 pcb.pid() 380 ); 381 worker_private 382 .as_mut() 383 .unwrap() 384 .kernel_thread_mut() 385 .expect("Error type of worker private") 386 .flags 387 .insert(KernelThreadFlags::SHOULD_STOP); 388 389 drop(worker_private); 390 391 ProcessManager::wakeup(pcb).ok(); 392 393 // 忙等目标内核线程退出 394 // todo: 使用completion机制优化这里 395 loop { 396 if let ProcessState::Exited(code) = pcb.sched_info().inner_lock_read_irqsave().state() { 397 return Ok(code); 398 } 399 spin_loop(); 400 } 401 } 402 403 /// 判断一个内核线程是否应当停止 404 /// 405 /// ## 参数 406 /// 407 /// - pcb: 目标内核线程的PCB 408 /// 409 /// ## 返回值 410 /// 411 /// - bool 是否应当停止. true表示应当停止，false表示不应当停止. 如果目标进程不是内核线程，返回false 412 /// 413 /// ## Panic 414 /// 415 /// 如果目标内核线程的数据检查失败，会panic 416 #[allow(dead_code)] 417 pub fn should_stop(pcb: &Arc<ProcessControlBlock>) -> bool { 418 if !pcb.flags().contains(ProcessFlags::KTHREAD) { 419 return false; 420 } 421 422 let worker_private = pcb.worker_private(); 423 assert!( 424 worker_private.is_some(), 425 "kthread should_stop: worker_private is none, pid: {:?}", 426 pcb.pid() 427 ); 428 return worker_private 429 .as_ref() 430 .unwrap() 431 .kernel_thread() 432 .expect("Error type of worker private") 433 .flags 434 .contains(KernelThreadFlags::SHOULD_STOP); 435 } 436 437 /// A daemon thread which creates other kernel threads 438 fn kthread_daemon() -> i32 { 439 let current_pcb = ProcessManager::current_pcb(); 440 kdebug!("kthread_daemon: pid: {:?}", current_pcb.pid()); 441 { 442 // 初始化worker_private 443 let mut worker_private_guard = current_pcb.worker_private(); 444 let worker_private = WorkerPrivate::KernelThread(KernelThreadPcbPrivate::new()); 445 *worker_private_guard = Some(worker_private); 446 } 447 // 设置为kthread 448 current_pcb.flags().insert(ProcessFlags::KTHREAD); 449 drop(current_pcb); 450 451 loop { 452 let mut list = KTHREAD_CREATE_LIST.lock(); 453 while let Some(info) = list.pop_front() { 454 drop(list); 455 456 // create a new kernel thread 457 let result: Result<Pid, SystemError> = 458 Self::__inner_create(&info, CloneFlags::CLONE_FS | CloneFlags::CLONE_SIGNAL); 459 460 if result.is_err() { 461 // 创建失败 462 info.created 463 .store(KernelThreadCreateStatus::ErrorOccured, Ordering::SeqCst); 464 }; 465 list = KTHREAD_CREATE_LIST.lock(); 466 } 467 drop(list); 468 469 let irq_guard = unsafe { CurrentIrqArch::save_and_disable_irq() }; 470 ProcessManager::mark_sleep(true).ok(); 471 drop(irq_guard); 472 sched(); 473 } 474 } 475 } 476 477 /// 内核线程启动的第二阶段 478 /// 479 /// 该函数只能被`kernel_thread_bootstrap_stage1`调用（jmp到该函数） 480 /// 481 /// ## 参数 482 /// 483 /// - ptr: 传入的参数，是一个指向`Arc<KernelThreadCreateInfo>`的指针 484 pub unsafe extern "C" fn kernel_thread_bootstrap_stage2(ptr: *const KernelThreadCreateInfo) -> ! { 485 let info = KernelThreadCreateInfo::parse_unsafe_arc_ptr(ptr); 486 487 let closure: Box<KernelThreadClosure> = info.take_closure().unwrap(); 488 info.set_create_ok(ProcessManager::current_pcb()); 489 let to_mark_sleep = info.to_mark_sleep(); 490 drop(info); 491 492 if to_mark_sleep { 493 // 进入睡眠状态 494 let irq_guard = CurrentIrqArch::save_and_disable_irq(); 495 ProcessManager::mark_sleep(true).expect("Failed to mark sleep"); 496 drop(irq_guard); 497 sched(); 498 } 499 500 let mut retval = SystemError::EINTR.to_posix_errno(); 501 502 if !KernelThreadMechanism::should_stop(&ProcessManager::current_pcb()) { 503 retval = closure.run(); 504 } 505 506 ProcessManager::exit(retval as usize); 507 } 508 509 /// 初始化内核线程机制 510 #[inline(never)] 511 pub fn kthread_init() { 512 static INIT: Once = Once::new(); 513 INIT.call_once(|| { 514 KernelThreadMechanism::init_stage1(); 515 }); 516 } 517