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 } 116 117 #[atomic_enum] 118 #[derive(PartialEq)] 119 pub enum KernelThreadCreateStatus { 120 Created, 121 NotCreated, 122 ErrorOccured, 123 } 124 125 #[allow(dead_code)] 126 impl KernelThreadCreateInfo { 127 pub fn new(func: KernelThreadClosure, name: String) -> Arc<Self> { 128 let result = Arc::new(Self { 129 closure: SpinLock::new(Some(Box::new(func))), 130 name, 131 created: AtomicKernelThreadCreateStatus::new(KernelThreadCreateStatus::NotCreated), 132 result_pcb: SpinLock::new(None), 133 has_unsafe_arc_instance: AtomicBool::new(false), 134 self_ref: Weak::new(), 135 }); 136 let tmp = result.clone(); 137 unsafe { 138 let tmp = Arc::into_raw(tmp) as *mut Self; 139 (*tmp).self_ref = Arc::downgrade(&result); 140 Arc::from_raw(tmp); 141 } 142 143 return result; 144 } 145 146 /// 创建者调用这函数，等待创建完成后，获取创建结果 147 /// 148 /// ## 返回值 149 /// 150 /// - Some(Arc<ProcessControlBlock>) 创建成功，返回新创建的内核线程的PCB 151 /// - None 创建失败 152 pub fn poll_result(&self) -> Option<Arc<ProcessControlBlock>> { 153 loop { 154 match self.created.load(Ordering::SeqCst) { 155 KernelThreadCreateStatus::Created => { 156 return self.result_pcb.lock().take(); 157 } 158 KernelThreadCreateStatus::NotCreated => { 159 spin_loop(); 160 } 161 KernelThreadCreateStatus::ErrorOccured => { 162 // 创建失败，减少不安全的Arc引用计数 163 let to_delete = self.has_unsafe_arc_instance.swap(false, Ordering::SeqCst); 164 if to_delete { 165 let self_ref = self.self_ref.upgrade().unwrap(); 166 unsafe { Arc::decrement_strong_count(&self_ref) }; 167 } 168 return None; 169 } 170 } 171 } 172 } 173 174 pub fn take_closure(&self) -> Option<Box<KernelThreadClosure>> { 175 return self.closure.lock().take(); 176 } 177 178 pub fn name(&self) -> &String { 179 &self.name 180 } 181 182 pub unsafe fn set_create_ok(&self, pcb: Arc<ProcessControlBlock>) { 183 // todo: 使用completion机制优化这里 184 self.result_pcb.lock().replace(pcb); 185 self.created 186 .store(KernelThreadCreateStatus::Created, Ordering::SeqCst); 187 } 188 189 /// 生成一个不安全的Arc指针（用于创建内核线程时传递参数） 190 pub fn generate_unsafe_arc_ptr(self: Arc<Self>) -> *const Self { 191 assert!( 192 self.has_unsafe_arc_instance 193 .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst) 194 .is_ok(), 195 "Cannot generate unsafe arc ptr when there is already one." 196 ); 197 let ptr = Arc::into_raw(self); 198 return ptr; 199 } 200 201 pub unsafe fn parse_unsafe_arc_ptr(ptr: *const Self) -> Arc<Self> { 202 let arc = Arc::from_raw(ptr); 203 assert!( 204 arc.has_unsafe_arc_instance 205 .compare_exchange(true, false, Ordering::SeqCst, Ordering::SeqCst) 206 .is_ok(), 207 "Cannot parse unsafe arc ptr when there is no one." 208 ); 209 assert!(Arc::strong_count(&arc) > 0); 210 return arc; 211 } 212 } 213 214 pub struct KernelThreadMechanism; 215 216 impl KernelThreadMechanism { 217 pub fn init_stage1() { 218 kinfo!("Initializing kernel thread mechanism stage1..."); 219 220 // 初始化第一个内核线程 221 222 let create_info = KernelThreadCreateInfo::new( 223 KernelThreadClosure::EmptyClosure((Box::new(initial_kernel_thread), ())), 224 "init".to_string(), 225 ); 226 let irq_guard = unsafe { CurrentIrqArch::save_and_disable_irq() }; 227 // 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 228 ProcessManager::current_pcb() 229 .flags 230 .lock() 231 .insert(ProcessFlags::KTHREAD); 232 233 KernelThreadMechanism::__inner_create( 234 &create_info, 235 CloneFlags::CLONE_VM | CloneFlags::CLONE_SIGNAL, 236 ) 237 .unwrap_or_else(|e| panic!("Failed to create initial kernel thread, error: {:?}", e)); 238 239 ProcessManager::current_pcb() 240 .flags 241 .lock() 242 .remove(ProcessFlags::KTHREAD); 243 drop(irq_guard); 244 kinfo!("Initializing kernel thread mechanism stage1 complete"); 245 } 246 247 pub fn init_stage2() { 248 assert!(ProcessManager::current_pcb() 249 .flags() 250 .contains(ProcessFlags::KTHREAD)); 251 static INIT: Once = Once::new(); 252 INIT.call_once(|| { 253 kinfo!("Initializing kernel thread mechanism stage2..."); 254 // 初始化kthreadd 255 let closure = KernelThreadClosure::EmptyClosure((Box::new(Self::kthread_daemon), ())); 256 let info = KernelThreadCreateInfo::new(closure, "kthreadd".to_string()); 257 let kthreadd_pid: Pid = 258 Self::__inner_create(&info, CloneFlags::CLONE_FS | CloneFlags::CLONE_SIGNAL) 259 .expect("Failed to create kthread daemon"); 260 261 let pcb = ProcessManager::find(kthreadd_pid).unwrap(); 262 unsafe { 263 KTHREAD_DAEMON_PCB.replace(pcb); 264 } 265 kinfo!("Initializing kernel thread mechanism stage2 complete"); 266 }); 267 } 268 269 /// 创建一个新的内核线程 270 /// 271 /// ## 参数 272 /// 273 /// - func: 内核线程的入口函数、传入参数 274 /// - name: 内核线程的名字 275 /// 276 /// ## 返回值 277 /// 278 /// - Some(Arc<ProcessControlBlock>) 创建成功，返回新创建的内核线程的PCB 279 #[allow(dead_code)] 280 pub fn create(func: KernelThreadClosure, name: String) -> Option<Arc<ProcessControlBlock>> { 281 let info = KernelThreadCreateInfo::new(func, name); 282 while unsafe { KTHREAD_DAEMON_PCB.is_none() } { 283 // 等待kthreadd启动 284 spin_loop() 285 } 286 KTHREAD_CREATE_LIST.lock().push_back(info.clone()); 287 ProcessManager::wakeup(unsafe { KTHREAD_DAEMON_PCB.as_ref().unwrap() }) 288 .expect("Failed to wakeup kthread daemon"); 289 return info.poll_result(); 290 } 291 292 /// 创建并运行一个新的内核线程 293 /// 294 /// ## 参数 295 /// 296 /// - func: 内核线程的入口函数、传入参数 297 /// - name: 内核线程的名字 298 /// 299 /// ## 返回值 300 /// 301 /// - Some(Arc<ProcessControlBlock>) 创建成功，返回新创建的内核线程的PCB 302 #[allow(dead_code)] 303 pub fn create_and_run( 304 func: KernelThreadClosure, 305 name: String, 306 ) -> Option<Arc<ProcessControlBlock>> { 307 let pcb = Self::create(func, name)?; 308 ProcessManager::wakeup(&pcb) 309 .expect(format!("Failed to wakeup kthread: {:?}", pcb.pid()).as_str()); 310 return Some(pcb); 311 } 312 313 /// 停止一个内核线程 314 /// 315 /// 如果目标内核线程的数据检查失败，会panic 316 /// 317 /// ## 返回值 318 /// 319 /// - Ok(i32) 目标内核线程的退出码 320 #[allow(dead_code)] 321 pub fn stop(pcb: &Arc<ProcessControlBlock>) -> Result<usize, SystemError> { 322 if !pcb.flags().contains(ProcessFlags::KTHREAD) { 323 panic!("Cannt stop a non-kthread process"); 324 } 325 326 let mut worker_private = pcb.worker_private(); 327 assert!( 328 worker_private.is_some(), 329 "kthread stop: worker_private is none, pid: {:?}", 330 pcb.pid() 331 ); 332 worker_private 333 .as_mut() 334 .unwrap() 335 .kernel_thread_mut() 336 .expect("Error type of worker private") 337 .flags 338 .insert(KernelThreadFlags::SHOULD_STOP); 339 340 drop(worker_private); 341 342 ProcessManager::wakeup(pcb).ok(); 343 344 // 忙等目标内核线程退出 345 // todo: 使用completion机制优化这里 346 loop { 347 if let ProcessState::Exited(code) = pcb.sched_info().state() { 348 return Ok(code); 349 } 350 spin_loop(); 351 } 352 } 353 354 /// 判断一个内核线程是否应当停止 355 /// 356 /// ## 参数 357 /// 358 /// - pcb: 目标内核线程的PCB 359 /// 360 /// ## 返回值 361 /// 362 /// - 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 363 /// 364 /// ## Panic 365 /// 366 /// 如果目标内核线程的数据检查失败，会panic 367 #[allow(dead_code)] 368 pub fn should_stop(pcb: &Arc<ProcessControlBlock>) -> bool { 369 if !pcb.flags().contains(ProcessFlags::KTHREAD) { 370 return false; 371 } 372 373 let worker_private = pcb.worker_private(); 374 assert!( 375 worker_private.is_some(), 376 "kthread should_stop: worker_private is none, pid: {:?}", 377 pcb.pid() 378 ); 379 return worker_private 380 .as_ref() 381 .unwrap() 382 .kernel_thread() 383 .expect("Error type of worker private") 384 .flags 385 .contains(KernelThreadFlags::SHOULD_STOP); 386 } 387 388 /// A daemon thread which creates other kernel threads 389 fn kthread_daemon() -> i32 { 390 let current_pcb = ProcessManager::current_pcb(); 391 kdebug!("kthread_daemon: pid: {:?}", current_pcb.pid()); 392 { 393 // 初始化worker_private 394 let mut worker_private_guard = current_pcb.worker_private(); 395 let worker_private = WorkerPrivate::KernelThread(KernelThreadPcbPrivate::new()); 396 *worker_private_guard = Some(worker_private); 397 } 398 // 设置为kthread 399 current_pcb.flags().insert(ProcessFlags::KTHREAD); 400 drop(current_pcb); 401 402 loop { 403 let mut list = KTHREAD_CREATE_LIST.lock(); 404 while let Some(info) = list.pop_front() { 405 drop(list); 406 407 // create a new kernel thread 408 let result: Result<Pid, SystemError> = 409 Self::__inner_create(&info, CloneFlags::CLONE_FS | CloneFlags::CLONE_SIGNAL); 410 411 if result.is_err() { 412 // 创建失败 413 info.created 414 .store(KernelThreadCreateStatus::ErrorOccured, Ordering::SeqCst); 415 }; 416 list = KTHREAD_CREATE_LIST.lock(); 417 } 418 drop(list); 419 420 let irq_guard = unsafe { CurrentIrqArch::save_and_disable_irq() }; 421 ProcessManager::mark_sleep(true).ok(); 422 drop(irq_guard); 423 sched(); 424 } 425 } 426 } 427 428 /// 内核线程启动的第二阶段 429 /// 430 /// 该函数只能被`kernel_thread_bootstrap_stage1`调用（jmp到该函数） 431 /// 432 /// ## 参数 433 /// 434 /// - ptr: 传入的参数，是一个指向`Arc<KernelThreadCreateInfo>`的指针 435 pub unsafe extern "C" fn kernel_thread_bootstrap_stage2(ptr: *const KernelThreadCreateInfo) -> ! { 436 let info = KernelThreadCreateInfo::parse_unsafe_arc_ptr(ptr); 437 438 let closure: Box<KernelThreadClosure> = info.take_closure().unwrap(); 439 info.set_create_ok(ProcessManager::current_pcb()); 440 drop(info); 441 442 let irq_guard = CurrentIrqArch::save_and_disable_irq(); 443 ProcessManager::mark_sleep(true).expect("Failed to mark sleep"); 444 drop(irq_guard); 445 446 let mut retval = SystemError::EINTR.to_posix_errno(); 447 448 if !KernelThreadMechanism::should_stop(&ProcessManager::current_pcb()) { 449 retval = closure.run(); 450 } 451 452 ProcessManager::exit(retval as usize); 453 } 454 455 pub fn kthread_init() { 456 static INIT: Once = Once::new(); 457 INIT.call_once(|| { 458 KernelThreadMechanism::init_stage1(); 459 }); 460 } 461