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