1 // 进程的用户空间内存管理 2 3 use core::{ 4 cmp, 5 hash::Hasher, 6 intrinsics::unlikely, 7 ops::Add, 8 sync::atomic::{compiler_fence, Ordering}, 9 }; 10 11 use alloc::{ 12 collections::BTreeMap, 13 sync::{Arc, Weak}, 14 vec::Vec, 15 }; 16 use hashbrown::HashSet; 17 use ida::IdAllocator; 18 use system_error::SystemError; 19 20 use crate::{ 21 arch::{mm::PageMapper, CurrentIrqArch, MMArch}, 22 exception::InterruptArch, 23 libs::{ 24 align::page_align_up, 25 rwlock::{RwLock, RwLockWriteGuard}, 26 spinlock::{SpinLock, SpinLockGuard}, 27 }, 28 mm::page::page_manager_lock_irasave, 29 process::ProcessManager, 30 syscall::user_access::{UserBufferReader, UserBufferWriter}, 31 }; 32 33 use super::{ 34 allocator::page_frame::{ 35 deallocate_page_frames, PageFrameCount, PhysPageFrame, VirtPageFrame, VirtPageFrameIter, 36 }, 37 page::{Flusher, InactiveFlusher, PageFlags, PageFlushAll}, 38 syscall::{MapFlags, MremapFlags, ProtFlags}, 39 MemoryManagementArch, PageTableKind, VirtAddr, VirtRegion, VmFlags, 40 }; 41 42 /// MMAP_MIN_ADDR的默认值 43 /// 以下内容来自linux-5.19: 44 /// This is the portion of low virtual memory which should be protected 45 // from userspace allocation. Keeping a user from writing to low pages 46 // can help reduce the impact of kernel NULL pointer bugs. 47 // For most ia64, ppc64 and x86 users with lots of address space 48 // a value of 65536 is reasonable and should cause no problems. 49 // On arm and other archs it should not be higher than 32768. 50 // Programs which use vm86 functionality or have some need to map 51 // this low address space will need CAP_SYS_RAWIO or disable this 52 // protection by setting the value to 0. 53 pub const DEFAULT_MMAP_MIN_ADDR: usize = 65536; 54 55 /// LockedVMA的id分配器 56 static LOCKEDVMA_ID_ALLOCATOR: IdAllocator = IdAllocator::new(0, usize::MAX); 57 58 #[derive(Debug)] 59 pub struct AddressSpace { 60 inner: RwLock<InnerAddressSpace>, 61 } 62 63 impl AddressSpace { 64 pub fn new(create_stack: bool) -> Result<Arc<Self>, SystemError> { 65 let inner = InnerAddressSpace::new(create_stack)?; 66 let result = Self { 67 inner: RwLock::new(inner), 68 }; 69 return Ok(Arc::new(result)); 70 } 71 72 /// 从pcb中获取当前进程的地址空间结构体的Arc指针 73 pub fn current() -> Result<Arc<AddressSpace>, SystemError> { 74 let vm = ProcessManager::current_pcb() 75 .basic() 76 .user_vm() 77 .expect("Current process has no address space"); 78 79 return Ok(vm); 80 } 81 82 /// 判断某个地址空间是否为当前进程的地址空间 83 pub fn is_current(self: &Arc<Self>) -> bool { 84 let current = Self::current(); 85 if let Ok(current) = current { 86 return Arc::ptr_eq(¤t, self); 87 } 88 return false; 89 } 90 } 91 92 impl core::ops::Deref for AddressSpace { 93 type Target = RwLock<InnerAddressSpace>; 94 95 fn deref(&self) -> &Self::Target { 96 &self.inner 97 } 98 } 99 100 impl core::ops::DerefMut for AddressSpace { 101 fn deref_mut(&mut self) -> &mut Self::Target { 102 &mut self.inner 103 } 104 } 105 106 /// @brief 用户地址空间结构体（每个进程都有一个） 107 #[derive(Debug)] 108 pub struct InnerAddressSpace { 109 pub user_mapper: UserMapper, 110 pub mappings: UserMappings, 111 pub mmap_min: VirtAddr, 112 /// 用户栈信息结构体 113 pub user_stack: Option<UserStack>, 114 115 pub elf_brk_start: VirtAddr, 116 pub elf_brk: VirtAddr, 117 118 /// 当前进程的堆空间的起始地址 119 pub brk_start: VirtAddr, 120 /// 当前进程的堆空间的结束地址(不包含) 121 pub brk: VirtAddr, 122 123 pub start_code: VirtAddr, 124 pub end_code: VirtAddr, 125 pub start_data: VirtAddr, 126 pub end_data: VirtAddr, 127 } 128 129 impl InnerAddressSpace { 130 pub fn new(create_stack: bool) -> Result<Self, SystemError> { 131 let mut result = Self { 132 user_mapper: MMArch::setup_new_usermapper()?, 133 mappings: UserMappings::new(), 134 mmap_min: VirtAddr(DEFAULT_MMAP_MIN_ADDR), 135 elf_brk_start: VirtAddr::new(0), 136 elf_brk: VirtAddr::new(0), 137 brk_start: MMArch::USER_BRK_START, 138 brk: MMArch::USER_BRK_START, 139 user_stack: None, 140 start_code: VirtAddr(0), 141 end_code: VirtAddr(0), 142 start_data: VirtAddr(0), 143 end_data: VirtAddr(0), 144 }; 145 if create_stack { 146 // kdebug!("to create user stack."); 147 result.new_user_stack(UserStack::DEFAULT_USER_STACK_SIZE)?; 148 } 149 150 return Ok(result); 151 } 152 153 /// 尝试克隆当前进程的地址空间，包括这些映射都会被克隆 154 /// 155 /// # Returns 156 /// 157 /// 返回克隆后的，新的地址空间的Arc指针 158 #[inline(never)] 159 pub fn try_clone(&mut self) -> Result<Arc<AddressSpace>, SystemError> { 160 let irq_guard = unsafe { CurrentIrqArch::save_and_disable_irq() }; 161 let new_addr_space = AddressSpace::new(false)?; 162 let mut new_guard = new_addr_space.write(); 163 164 // 拷贝用户栈的结构体信息，但是不拷贝用户栈的内容（因为后面VMA的拷贝会拷贝用户栈的内容） 165 unsafe { 166 new_guard.user_stack = Some(self.user_stack.as_ref().unwrap().clone_info_only()); 167 } 168 let _current_stack_size = self.user_stack.as_ref().unwrap().stack_size(); 169 170 let current_mapper = &mut self.user_mapper.utable; 171 172 // 拷贝空洞 173 new_guard.mappings.vm_holes = self.mappings.vm_holes.clone(); 174 175 for vma in self.mappings.vmas.iter() { 176 // TODO: 增加对VMA是否为文件映射的判断，如果是的话，就跳过 177 178 let vma_guard: SpinLockGuard<'_, VMA> = vma.lock(); 179 let old_flags = vma_guard.flags(); 180 let tmp_flags: PageFlags<MMArch> = PageFlags::new().set_write(true); 181 182 // 分配内存页并创建新的VMA 183 let new_vma = VMA::zeroed( 184 VirtPageFrame::new(vma_guard.region.start()), 185 PageFrameCount::new(vma_guard.region.size() / MMArch::PAGE_SIZE), 186 *vma_guard.vm_flags(), 187 tmp_flags, 188 &mut new_guard.user_mapper.utable, 189 (), 190 )?; 191 new_guard.mappings.vmas.insert(new_vma.clone()); 192 // kdebug!("new vma: {:x?}", new_vma); 193 let mut new_vma_guard = new_vma.lock(); 194 for page in new_vma_guard.pages().map(|p| p.virt_address()) { 195 // kdebug!("page: {:x?}", page); 196 let current_frame = unsafe { 197 MMArch::phys_2_virt( 198 current_mapper 199 .translate(page) 200 .expect("VMA page not mapped") 201 .0, 202 ) 203 } 204 .expect("Phys2Virt: vaddr overflow.") 205 .data() as *mut u8; 206 207 let new_frame = unsafe { 208 MMArch::phys_2_virt( 209 new_guard 210 .user_mapper 211 .utable 212 .translate(page) 213 .expect("VMA page not mapped") 214 .0, 215 ) 216 } 217 .expect("Phys2Virt: vaddr overflow.") 218 .data() as *mut u8; 219 220 unsafe { 221 // 拷贝数据 222 new_frame.copy_from_nonoverlapping(current_frame, MMArch::PAGE_SIZE); 223 } 224 } 225 drop(vma_guard); 226 227 new_vma_guard.remap(old_flags, &mut new_guard.user_mapper.utable, ())?; 228 drop(new_vma_guard); 229 } 230 drop(new_guard); 231 drop(irq_guard); 232 return Ok(new_addr_space); 233 } 234 235 /// 判断当前的地址空间是否是当前进程的地址空间 236 #[inline] 237 pub fn is_current(&self) -> bool { 238 return self.user_mapper.utable.is_current(); 239 } 240 241 /// 进行匿名页映射 242 /// 243 /// ## 参数 244 /// 245 /// - `start_vaddr`：映射的起始地址 246 /// - `len`：映射的长度 247 /// - `prot_flags`：保护标志 248 /// - `map_flags`：映射标志 249 /// - `round_to_min`：是否将`start_vaddr`对齐到`mmap_min`，如果为`true`，则当`start_vaddr`不为0时，会对齐到`mmap_min`，否则仅向下对齐到页边界 250 /// 251 /// ## 返回 252 /// 253 /// 返回映射的起始虚拟页帧 254 pub fn map_anonymous( 255 &mut self, 256 start_vaddr: VirtAddr, 257 len: usize, 258 prot_flags: ProtFlags, 259 map_flags: MapFlags, 260 round_to_min: bool, 261 ) -> Result<VirtPageFrame, SystemError> { 262 // 用于对齐hint的函数 263 let round_hint_to_min = |hint: VirtAddr| { 264 // 先把hint向下对齐到页边界 265 let addr = hint.data() & (!MMArch::PAGE_OFFSET_MASK); 266 // kdebug!("map_anonymous: hint = {:?}, addr = {addr:#x}", hint); 267 // 如果hint不是0，且hint小于DEFAULT_MMAP_MIN_ADDR，则对齐到DEFAULT_MMAP_MIN_ADDR 268 if (addr != 0) && round_to_min && (addr < DEFAULT_MMAP_MIN_ADDR) { 269 Some(VirtAddr::new(page_align_up(DEFAULT_MMAP_MIN_ADDR))) 270 } else if addr == 0 { 271 None 272 } else { 273 Some(VirtAddr::new(addr)) 274 } 275 }; 276 // kdebug!("map_anonymous: start_vaddr = {:?}", start_vaddr); 277 // kdebug!("map_anonymous: len(no align) = {}", len); 278 279 let len = page_align_up(len); 280 281 let vm_flags = VmFlags::from(prot_flags) 282 | VmFlags::from(map_flags) 283 | VmFlags::VM_MAYREAD 284 | VmFlags::VM_MAYWRITE 285 | VmFlags::VM_MAYEXEC; 286 287 // kdebug!("map_anonymous: len = {}", len); 288 289 let start_page: VirtPageFrame = self.mmap( 290 round_hint_to_min(start_vaddr), 291 PageFrameCount::from_bytes(len).unwrap(), 292 prot_flags, 293 map_flags, 294 move |page, count, flags, mapper, flusher| { 295 VMA::zeroed(page, count, vm_flags, flags, mapper, flusher) 296 }, 297 )?; 298 299 return Ok(start_page); 300 } 301 302 /// 向进程的地址空间映射页面 303 /// 304 /// # 参数 305 /// 306 /// - `addr`：映射的起始地址，如果为`None`，则由内核自动分配 307 /// - `page_count`：映射的页面数量 308 /// - `prot_flags`：保护标志 309 /// - `map_flags`：映射标志 310 /// - `map_func`：映射函数，用于创建VMA 311 /// 312 /// # Returns 313 /// 314 /// 返回映射的起始虚拟页帧 315 /// 316 /// # Errors 317 /// 318 /// - `EINVAL`：参数错误 319 pub fn mmap< 320 F: FnOnce( 321 VirtPageFrame, 322 PageFrameCount, 323 PageFlags<MMArch>, 324 &mut PageMapper, 325 &mut dyn Flusher<MMArch>, 326 ) -> Result<Arc<LockedVMA>, SystemError>, 327 >( 328 &mut self, 329 addr: Option<VirtAddr>, 330 page_count: PageFrameCount, 331 prot_flags: ProtFlags, 332 map_flags: MapFlags, 333 map_func: F, 334 ) -> Result<VirtPageFrame, SystemError> { 335 if page_count == PageFrameCount::new(0) { 336 return Err(SystemError::EINVAL); 337 } 338 // kdebug!("mmap: addr: {addr:?}, page_count: {page_count:?}, prot_flags: {prot_flags:?}, map_flags: {map_flags:?}"); 339 340 // 找到未使用的区域 341 let region = match addr { 342 Some(vaddr) => { 343 self.mappings 344 .find_free_at(self.mmap_min, vaddr, page_count.bytes(), map_flags)? 345 } 346 None => self 347 .mappings 348 .find_free(self.mmap_min, page_count.bytes()) 349 .ok_or(SystemError::ENOMEM)?, 350 }; 351 352 let page = VirtPageFrame::new(region.start()); 353 354 // kdebug!("mmap: page: {:?}, region={region:?}", page.virt_address()); 355 356 compiler_fence(Ordering::SeqCst); 357 let (mut active, mut inactive); 358 let flusher = if self.is_current() { 359 active = PageFlushAll::new(); 360 &mut active as &mut dyn Flusher<MMArch> 361 } else { 362 inactive = InactiveFlusher::new(); 363 &mut inactive as &mut dyn Flusher<MMArch> 364 }; 365 compiler_fence(Ordering::SeqCst); 366 // 映射页面，并将VMA插入到地址空间的VMA列表中 367 self.mappings.insert_vma(map_func( 368 page, 369 page_count, 370 PageFlags::from_prot_flags(prot_flags, true), 371 &mut self.user_mapper.utable, 372 flusher, 373 )?); 374 375 return Ok(page); 376 } 377 378 /// 重映射内存区域 379 /// 380 /// # 参数 381 /// 382 /// - `old_vaddr`：原映射的起始地址 383 /// - `old_len`：原映射的长度 384 /// - `new_len`：重新映射的长度 385 /// - `mremap_flags`：重映射标志 386 /// - `new_vaddr`：重新映射的起始地址 387 /// - `vm_flags`：旧内存区域标志 388 /// 389 /// # Returns 390 /// 391 /// 返回重映射的起始虚拟页帧地址 392 /// 393 /// # Errors 394 /// 395 /// - `EINVAL`：参数错误 396 pub fn mremap( 397 &mut self, 398 old_vaddr: VirtAddr, 399 old_len: usize, 400 new_len: usize, 401 mremap_flags: MremapFlags, 402 new_vaddr: VirtAddr, 403 vm_flags: VmFlags, 404 ) -> Result<VirtAddr, SystemError> { 405 // 检查新内存地址是否对齐 406 if !new_vaddr.check_aligned(MMArch::PAGE_SIZE) { 407 return Err(SystemError::EINVAL); 408 } 409 410 // 检查新、旧内存区域是否冲突 411 let old_region = VirtRegion::new(old_vaddr, old_len); 412 let new_region = VirtRegion::new(new_vaddr, new_len); 413 if old_region.collide(&new_region) { 414 return Err(SystemError::EINVAL); 415 } 416 417 // 初始化映射标志 418 let mut map_flags: MapFlags = vm_flags.into(); 419 // 初始化内存区域保护标志 420 let prot_flags: ProtFlags = vm_flags.into(); 421 422 // 取消新内存区域的原映射 423 if mremap_flags.contains(MremapFlags::MREMAP_FIXED) { 424 map_flags |= MapFlags::MAP_FIXED; 425 let start_page = VirtPageFrame::new(new_vaddr); 426 let page_count = PageFrameCount::from_bytes(new_len).unwrap(); 427 self.munmap(start_page, page_count)?; 428 } 429 430 // 获取映射后的新内存页面 431 let new_page = self.map_anonymous(new_vaddr, new_len, prot_flags, map_flags, true)?; 432 let new_page_vaddr = new_page.virt_address(); 433 434 // 拷贝旧内存区域内容到新内存区域 435 let old_buffer_reader = 436 UserBufferReader::new(old_vaddr.data() as *const u8, old_len, true)?; 437 let old_buf: &[u8] = old_buffer_reader.read_from_user(0)?; 438 let mut new_buffer_writer = 439 UserBufferWriter::new(new_page_vaddr.data() as *mut u8, new_len, true)?; 440 let new_buf: &mut [u8] = new_buffer_writer.buffer(0)?; 441 let len = old_buf.len().min(new_buf.len()); 442 new_buf[..len].copy_from_slice(&old_buf[..len]); 443 444 return Ok(new_page_vaddr); 445 } 446 447 /// 取消进程的地址空间中的映射 448 /// 449 /// # 参数 450 /// 451 /// - `start_page`：起始页帧 452 /// - `page_count`：取消映射的页帧数量 453 /// 454 /// # Errors 455 /// 456 /// - `EINVAL`：参数错误 457 /// - `ENOMEM`：内存不足 458 pub fn munmap( 459 &mut self, 460 start_page: VirtPageFrame, 461 page_count: PageFrameCount, 462 ) -> Result<(), SystemError> { 463 let to_unmap = VirtRegion::new(start_page.virt_address(), page_count.bytes()); 464 let mut flusher: PageFlushAll<MMArch> = PageFlushAll::new(); 465 466 let regions: Vec<Arc<LockedVMA>> = self.mappings.conflicts(to_unmap).collect::<Vec<_>>(); 467 468 for r in regions { 469 let r = r.lock().region; 470 let r = self.mappings.remove_vma(&r).unwrap(); 471 let intersection = r.lock().region().intersect(&to_unmap).unwrap(); 472 let split_result = r.extract(intersection, &self.user_mapper.utable).unwrap(); 473 474 // TODO: 当引入后备页映射后，这里需要增加通知文件的逻辑 475 476 if let Some(before) = split_result.prev { 477 // 如果前面有VMA，则需要将前面的VMA重新插入到地址空间的VMA列表中 478 self.mappings.insert_vma(before); 479 } 480 481 if let Some(after) = split_result.after { 482 // 如果后面有VMA，则需要将后面的VMA重新插入到地址空间的VMA列表中 483 self.mappings.insert_vma(after); 484 } 485 486 r.unmap(&mut self.user_mapper.utable, &mut flusher); 487 } 488 489 // TODO: 当引入后备页映射后，这里需要增加通知文件的逻辑 490 491 return Ok(()); 492 } 493 494 pub fn mprotect( 495 &mut self, 496 start_page: VirtPageFrame, 497 page_count: PageFrameCount, 498 prot_flags: ProtFlags, 499 ) -> Result<(), SystemError> { 500 // kdebug!( 501 // "mprotect: start_page: {:?}, page_count: {:?}, prot_flags:{prot_flags:?}", 502 // start_page, 503 // page_count 504 // ); 505 let (mut active, mut inactive); 506 let mut flusher = if self.is_current() { 507 active = PageFlushAll::new(); 508 &mut active as &mut dyn Flusher<MMArch> 509 } else { 510 inactive = InactiveFlusher::new(); 511 &mut inactive as &mut dyn Flusher<MMArch> 512 }; 513 514 let mapper = &mut self.user_mapper.utable; 515 let region = VirtRegion::new(start_page.virt_address(), page_count.bytes()); 516 // kdebug!("mprotect: region: {:?}", region); 517 518 let regions = self.mappings.conflicts(region).collect::<Vec<_>>(); 519 // kdebug!("mprotect: regions: {:?}", regions); 520 521 for r in regions { 522 // kdebug!("mprotect: r: {:?}", r); 523 let r = *r.lock().region(); 524 let r = self.mappings.remove_vma(&r).unwrap(); 525 526 let intersection = r.lock().region().intersect(®ion).unwrap(); 527 let split_result = r 528 .extract(intersection, mapper) 529 .expect("Failed to extract VMA"); 530 531 if let Some(before) = split_result.prev { 532 self.mappings.insert_vma(before); 533 } 534 if let Some(after) = split_result.after { 535 self.mappings.insert_vma(after); 536 } 537 538 let mut r_guard = r.lock(); 539 // 如果VMA的保护标志不允许指定的修改，则返回错误 540 if !r_guard.can_have_flags(prot_flags) { 541 drop(r_guard); 542 self.mappings.insert_vma(r.clone()); 543 return Err(SystemError::EACCES); 544 } 545 546 let new_flags: PageFlags<MMArch> = r_guard 547 .flags() 548 .set_execute(prot_flags.contains(ProtFlags::PROT_EXEC)) 549 .set_write(prot_flags.contains(ProtFlags::PROT_WRITE)); 550 551 r_guard.remap(new_flags, mapper, &mut flusher)?; 552 drop(r_guard); 553 self.mappings.insert_vma(r); 554 } 555 556 return Ok(()); 557 } 558 559 /// 创建新的用户栈 560 /// 561 /// ## 参数 562 /// 563 /// - `size`：栈的大小 564 pub fn new_user_stack(&mut self, size: usize) -> Result<(), SystemError> { 565 assert!(self.user_stack.is_none(), "User stack already exists"); 566 let stack = UserStack::new(self, None, size)?; 567 self.user_stack = Some(stack); 568 return Ok(()); 569 } 570 571 #[inline(always)] 572 pub fn user_stack_mut(&mut self) -> Option<&mut UserStack> { 573 return self.user_stack.as_mut(); 574 } 575 576 /// 取消用户空间内的所有映射 577 pub unsafe fn unmap_all(&mut self) { 578 let mut flusher: PageFlushAll<MMArch> = PageFlushAll::new(); 579 for vma in self.mappings.iter_vmas() { 580 vma.unmap(&mut self.user_mapper.utable, &mut flusher); 581 } 582 } 583 584 /// 设置进程的堆的内存空间 585 /// 586 /// ## 参数 587 /// 588 /// - `new_brk`：新的堆的结束地址。需要满足页对齐要求，并且是用户空间地址，且大于等于当前的堆的起始地址 589 /// 590 /// ## 返回值 591 /// 592 /// 返回旧的堆的结束地址 593 pub unsafe fn set_brk(&mut self, new_brk: VirtAddr) -> Result<VirtAddr, SystemError> { 594 assert!(new_brk.check_aligned(MMArch::PAGE_SIZE)); 595 596 if !new_brk.check_user() || new_brk < self.brk_start { 597 return Err(SystemError::EFAULT); 598 } 599 600 let old_brk = self.brk; 601 602 if new_brk > self.brk { 603 let len = new_brk - self.brk; 604 let prot_flags = ProtFlags::PROT_READ | ProtFlags::PROT_WRITE | ProtFlags::PROT_EXEC; 605 let map_flags = MapFlags::MAP_PRIVATE | MapFlags::MAP_ANONYMOUS | MapFlags::MAP_FIXED; 606 self.map_anonymous(old_brk, len, prot_flags, map_flags, true)?; 607 608 self.brk = new_brk; 609 return Ok(old_brk); 610 } else { 611 let unmap_len = self.brk - new_brk; 612 let unmap_start = new_brk; 613 if unmap_len == 0 { 614 return Ok(old_brk); 615 } 616 self.munmap( 617 VirtPageFrame::new(unmap_start), 618 PageFrameCount::from_bytes(unmap_len).unwrap(), 619 )?; 620 self.brk = new_brk; 621 return Ok(old_brk); 622 } 623 } 624 625 pub unsafe fn sbrk(&mut self, incr: isize) -> Result<VirtAddr, SystemError> { 626 if incr == 0 { 627 return Ok(self.brk); 628 } 629 630 let new_brk = if incr > 0 { 631 self.brk + incr as usize 632 } else { 633 self.brk - incr.unsigned_abs() 634 }; 635 636 let new_brk = VirtAddr::new(page_align_up(new_brk.data())); 637 638 return self.set_brk(new_brk); 639 } 640 } 641 642 impl Drop for InnerAddressSpace { 643 fn drop(&mut self) { 644 unsafe { 645 self.unmap_all(); 646 } 647 } 648 } 649 650 #[derive(Debug, Hash)] 651 pub struct UserMapper { 652 pub utable: PageMapper, 653 } 654 655 impl UserMapper { 656 pub fn new(utable: PageMapper) -> Self { 657 return Self { utable }; 658 } 659 } 660 661 impl Drop for UserMapper { 662 fn drop(&mut self) { 663 if self.utable.is_current() { 664 // 如果当前要被销毁的用户空间的页表是当前进程的页表，那么就切换回初始内核页表 665 unsafe { MMArch::set_table(PageTableKind::User, MMArch::initial_page_table()) } 666 } 667 // 释放用户空间顶层页表占用的页帧 668 // 请注意，在释放这个页帧之前，用户页表应该已经被完全释放，否则会产生内存泄露 669 unsafe { 670 deallocate_page_frames( 671 PhysPageFrame::new(self.utable.table().phys()), 672 PageFrameCount::new(1), 673 &mut page_manager_lock_irasave(), 674 ) 675 }; 676 } 677 } 678 679 /// 用户空间映射信息 680 #[derive(Debug)] 681 pub struct UserMappings { 682 /// 当前用户空间的虚拟内存区域 683 vmas: HashSet<Arc<LockedVMA>>, 684 /// 当前用户空间的VMA空洞 685 vm_holes: BTreeMap<VirtAddr, usize>, 686 } 687 688 impl UserMappings { 689 pub fn new() -> Self { 690 return Self { 691 vmas: HashSet::new(), 692 vm_holes: core::iter::once((VirtAddr::new(0), MMArch::USER_END_VADDR.data())) 693 .collect::<BTreeMap<_, _>>(), 694 }; 695 } 696 697 /// 判断当前进程的VMA内，是否有包含指定的虚拟地址的VMA。 698 /// 699 /// 如果有，返回包含指定虚拟地址的VMA的Arc指针，否则返回None。 700 #[allow(dead_code)] 701 pub fn contains(&self, vaddr: VirtAddr) -> Option<Arc<LockedVMA>> { 702 for v in self.vmas.iter() { 703 let guard = v.lock(); 704 if guard.region.contains(vaddr) { 705 return Some(v.clone()); 706 } 707 } 708 return None; 709 } 710 711 /// 获取当前进程的地址空间中，与给定虚拟地址范围有重叠的VMA的迭代器。 712 pub fn conflicts(&self, request: VirtRegion) -> impl Iterator<Item = Arc<LockedVMA>> + '_ { 713 let r = self 714 .vmas 715 .iter() 716 .filter(move |v| v.lock().region.intersect(&request).is_some()) 717 .cloned(); 718 return r; 719 } 720 721 /// 在当前进程的地址空间中，寻找第一个符合条件的空闲的虚拟内存范围。 722 /// 723 /// @param min_vaddr 最小的起始地址 724 /// @param size 请求的大小 725 /// 726 /// @return 如果找到了，返回虚拟内存范围，否则返回None 727 pub fn find_free(&self, min_vaddr: VirtAddr, size: usize) -> Option<VirtRegion> { 728 let _vaddr = min_vaddr; 729 let mut iter = self 730 .vm_holes 731 .iter() 732 .skip_while(|(hole_vaddr, hole_size)| hole_vaddr.add(**hole_size) <= min_vaddr); 733 734 let (hole_vaddr, size) = iter.find(|(hole_vaddr, hole_size)| { 735 // 计算当前空洞的可用大小 736 let available_size: usize = 737 if hole_vaddr <= &&min_vaddr && min_vaddr <= hole_vaddr.add(**hole_size) { 738 **hole_size - (min_vaddr - **hole_vaddr) 739 } else { 740 **hole_size 741 }; 742 743 size <= available_size 744 })?; 745 746 // 创建一个新的虚拟内存范围。 747 let region = VirtRegion::new(cmp::max(*hole_vaddr, min_vaddr), *size); 748 749 return Some(region); 750 } 751 752 pub fn find_free_at( 753 &self, 754 min_vaddr: VirtAddr, 755 vaddr: VirtAddr, 756 size: usize, 757 flags: MapFlags, 758 ) -> Result<VirtRegion, SystemError> { 759 // 如果没有指定地址，那么就在当前进程的地址空间中寻找一个空闲的虚拟内存范围。 760 if vaddr == VirtAddr::new(0) { 761 return self.find_free(min_vaddr, size).ok_or(SystemError::ENOMEM); 762 } 763 764 // 如果指定了地址，那么就检查指定的地址是否可用。 765 766 let requested = VirtRegion::new(vaddr, size); 767 768 if requested.end() >= MMArch::USER_END_VADDR || !vaddr.check_aligned(MMArch::PAGE_SIZE) { 769 return Err(SystemError::EINVAL); 770 } 771 772 if let Some(_x) = self.conflicts(requested).next() { 773 if flags.contains(MapFlags::MAP_FIXED_NOREPLACE) { 774 // 如果指定了 MAP_FIXED_NOREPLACE 标志，由于所指定的地址无法成功建立映射，则放弃映射，不对地址做修正 775 return Err(SystemError::EEXIST); 776 } 777 778 if flags.contains(MapFlags::MAP_FIXED) { 779 // todo: 支持MAP_FIXED标志对已有的VMA进行覆盖 780 return Err(SystemError::EOPNOTSUPP_OR_ENOTSUP); 781 } 782 783 // 如果没有指定MAP_FIXED标志，那么就对地址做修正 784 let requested = self.find_free(min_vaddr, size).ok_or(SystemError::ENOMEM)?; 785 return Ok(requested); 786 } 787 788 return Ok(requested); 789 } 790 791 /// 在当前进程的地址空间中，保留一个指定大小的区域，使得该区域不在空洞中。 792 /// 该函数会修改vm_holes中的空洞信息。 793 /// 794 /// @param region 要保留的区域 795 /// 796 /// 请注意，在调用本函数之前，必须先确定region所在范围内没有VMA。 797 fn reserve_hole(&mut self, region: &VirtRegion) { 798 let prev_hole: Option<(&VirtAddr, &mut usize)> = 799 self.vm_holes.range_mut(..=region.start()).next_back(); 800 801 if let Some((prev_hole_vaddr, prev_hole_size)) = prev_hole { 802 let prev_hole_end = prev_hole_vaddr.add(*prev_hole_size); 803 804 if prev_hole_end > region.start() { 805 // 如果前一个空洞的结束地址大于当前空洞的起始地址，那么就需要调整前一个空洞的大小。 806 *prev_hole_size = region.start().data() - prev_hole_vaddr.data(); 807 } 808 809 if prev_hole_end > region.end() { 810 // 如果前一个空洞的结束地址大于当前空洞的结束地址，那么就需要增加一个新的空洞。 811 self.vm_holes 812 .insert(region.end(), prev_hole_end - region.end()); 813 } 814 } 815 } 816 817 /// 在当前进程的地址空间中，释放一个指定大小的区域，使得该区域成为一个空洞。 818 /// 该函数会修改vm_holes中的空洞信息。 819 fn unreserve_hole(&mut self, region: &VirtRegion) { 820 // 如果将要插入的空洞与后一个空洞相邻，那么就需要合并。 821 let next_hole_size: Option<usize> = self.vm_holes.remove(®ion.end()); 822 823 if let Some((_prev_hole_vaddr, prev_hole_size)) = self 824 .vm_holes 825 .range_mut(..region.start()) 826 .next_back() 827 .filter(|(offset, size)| offset.data() + **size == region.start().data()) 828 { 829 *prev_hole_size += region.size() + next_hole_size.unwrap_or(0); 830 } else { 831 self.vm_holes 832 .insert(region.start(), region.size() + next_hole_size.unwrap_or(0)); 833 } 834 } 835 836 /// 在当前进程的映射关系中，插入一个新的VMA。 837 pub fn insert_vma(&mut self, vma: Arc<LockedVMA>) { 838 let region = vma.lock().region; 839 // 要求插入的地址范围必须是空闲的，也就是说，当前进程的地址空间中，不能有任何与之重叠的VMA。 840 assert!(self.conflicts(region).next().is_none()); 841 self.reserve_hole(®ion); 842 843 self.vmas.insert(vma); 844 } 845 846 /// @brief 删除一个VMA，并把对应的地址空间加入空洞中。 847 /// 848 /// 这里不会取消VMA对应的地址的映射 849 /// 850 /// @param region 要删除的VMA所在的地址范围 851 /// 852 /// @return 如果成功删除了VMA，则返回被删除的VMA，否则返回None 853 /// 如果没有可以删除的VMA，则不会执行删除操作，并报告失败。 854 pub fn remove_vma(&mut self, region: &VirtRegion) -> Option<Arc<LockedVMA>> { 855 // 请注意，由于这里会对每个VMA加锁，因此性能很低 856 let vma: Arc<LockedVMA> = self 857 .vmas 858 .drain_filter(|vma| vma.lock().region == *region) 859 .next()?; 860 self.unreserve_hole(region); 861 862 return Some(vma); 863 } 864 865 /// @brief Get the iterator of all VMAs in this process. 866 pub fn iter_vmas(&self) -> hashbrown::hash_set::Iter<Arc<LockedVMA>> { 867 return self.vmas.iter(); 868 } 869 } 870 871 impl Default for UserMappings { 872 fn default() -> Self { 873 return Self::new(); 874 } 875 } 876 877 /// 加了锁的VMA 878 /// 879 /// 备注：进行性能测试，看看SpinLock和RwLock哪个更快。 880 #[derive(Debug)] 881 pub struct LockedVMA { 882 /// 用于计算哈希值，避免总是获取vma锁来计算哈希值 883 id: usize, 884 vma: SpinLock<VMA>, 885 } 886 887 impl core::hash::Hash for LockedVMA { 888 fn hash<H: Hasher>(&self, state: &mut H) { 889 self.id.hash(state); 890 } 891 } 892 893 impl PartialEq for LockedVMA { 894 fn eq(&self, other: &Self) -> bool { 895 self.id.eq(&other.id) 896 } 897 } 898 899 impl Eq for LockedVMA {} 900 901 #[allow(dead_code)] 902 impl LockedVMA { 903 pub fn new(vma: VMA) -> Arc<Self> { 904 let r = Arc::new(Self { 905 id: LOCKEDVMA_ID_ALLOCATOR.alloc().unwrap(), 906 vma: SpinLock::new(vma), 907 }); 908 r.vma.lock().self_ref = Arc::downgrade(&r); 909 return r; 910 } 911 912 pub fn lock(&self) -> SpinLockGuard<VMA> { 913 return self.vma.lock(); 914 } 915 916 /// 调整当前VMA的页面的标志位 917 /// 918 /// TODO：增加调整虚拟页映射的物理地址的功能 919 /// 920 /// @param flags 新的标志位 921 /// @param mapper 页表映射器 922 /// @param flusher 页表项刷新器 923 /// 924 pub fn remap( 925 &self, 926 flags: PageFlags<MMArch>, 927 mapper: &mut PageMapper, 928 mut flusher: impl Flusher<MMArch>, 929 ) -> Result<(), SystemError> { 930 let mut guard = self.lock(); 931 assert!(guard.mapped); 932 for page in guard.region.pages() { 933 // 暂时要求所有的页帧都已经映射到页表 934 // TODO: 引入Lazy Mapping, 通过缺页中断来映射页帧，这里就不必要求所有的页帧都已经映射到页表了 935 let r = unsafe { 936 mapper 937 .remap(page.virt_address(), flags) 938 .expect("Failed to remap, beacuse of some page is not mapped") 939 }; 940 flusher.consume(r); 941 } 942 guard.flags = flags; 943 return Ok(()); 944 } 945 946 pub fn unmap(&self, mapper: &mut PageMapper, mut flusher: impl Flusher<MMArch>) { 947 // todo: 如果当前vma与文件相关，完善文件相关的逻辑 948 949 let mut guard = self.lock(); 950 assert!(guard.mapped); 951 952 // 获取物理页的anon_vma的守卫 953 let mut anon_vma_guard: SpinLockGuard<'_, crate::mm::page::PageManager> = 954 page_manager_lock_irasave(); 955 for page in guard.region.pages() { 956 let (paddr, _, flush) = unsafe { mapper.unmap_phys(page.virt_address(), true) } 957 .expect("Failed to unmap, beacuse of some page is not mapped"); 958 959 // 从anon_vma中删除当前VMA 960 let page = anon_vma_guard.get_mut(&paddr); 961 page.remove_vma(self); 962 963 // 如果物理页的anon_vma链表长度为0并且不是共享页，则释放物理页. 964 if page.can_deallocate() { 965 unsafe { 966 deallocate_page_frames( 967 PhysPageFrame::new(paddr), 968 PageFrameCount::new(1), 969 &mut anon_vma_guard, 970 ) 971 }; 972 } 973 974 flusher.consume(flush); 975 } 976 guard.mapped = false; 977 } 978 979 pub fn mapped(&self) -> bool { 980 return self.vma.lock().mapped; 981 } 982 983 /// 将当前VMA进行切分，切分成3个VMA，分别是： 984 /// 985 /// 1. 前面的VMA，如果没有则为None 986 /// 2. 中间的VMA，也就是传入的Region 987 /// 3. 后面的VMA，如果没有则为None 988 pub fn extract(&self, region: VirtRegion, utable: &PageMapper) -> Option<VMASplitResult> { 989 assert!(region.start().check_aligned(MMArch::PAGE_SIZE)); 990 assert!(region.end().check_aligned(MMArch::PAGE_SIZE)); 991 992 let mut guard = self.lock(); 993 { 994 // 如果传入的region不在当前VMA的范围内，则直接返回None 995 if unlikely(region.start() < guard.region.start() || region.end() > guard.region.end()) 996 { 997 return None; 998 } 999 1000 let intersect: Option<VirtRegion> = guard.region.intersect(®ion); 1001 // 如果当前VMA不包含region，则直接返回None 1002 if unlikely(intersect.is_none()) { 1003 return None; 1004 } 1005 let intersect: VirtRegion = intersect.unwrap(); 1006 if unlikely(intersect == guard.region) { 1007 // 如果当前VMA完全包含region，则直接返回当前VMA 1008 return Some(VMASplitResult::new( 1009 None, 1010 guard.self_ref.upgrade().unwrap(), 1011 None, 1012 )); 1013 } 1014 } 1015 1016 let before: Option<Arc<LockedVMA>> = guard.region.before(®ion).map(|virt_region| { 1017 let mut vma: VMA = unsafe { guard.clone() }; 1018 vma.region = virt_region; 1019 1020 let vma: Arc<LockedVMA> = LockedVMA::new(vma); 1021 vma 1022 }); 1023 1024 let after: Option<Arc<LockedVMA>> = guard.region.after(®ion).map(|virt_region| { 1025 let mut vma: VMA = unsafe { guard.clone() }; 1026 vma.region = virt_region; 1027 1028 let vma: Arc<LockedVMA> = LockedVMA::new(vma); 1029 vma 1030 }); 1031 1032 // 重新设置before、after这两个VMA里面的物理页的anon_vma 1033 let mut anon_vma_guard = page_manager_lock_irasave(); 1034 if let Some(before) = before.clone() { 1035 let virt_iter = before.lock().region.iter_pages(); 1036 for frame in virt_iter { 1037 let paddr = utable.translate(frame.virt_address()).unwrap().0; 1038 let page = anon_vma_guard.get_mut(&paddr); 1039 page.insert_vma(before.clone()); 1040 page.remove_vma(self); 1041 } 1042 } 1043 1044 if let Some(after) = after.clone() { 1045 let virt_iter = after.lock().region.iter_pages(); 1046 for frame in virt_iter { 1047 let paddr = utable.translate(frame.virt_address()).unwrap().0; 1048 let page = anon_vma_guard.get_mut(&paddr); 1049 page.insert_vma(after.clone()); 1050 page.remove_vma(self); 1051 } 1052 } 1053 1054 guard.region = region; 1055 1056 return Some(VMASplitResult::new( 1057 before, 1058 guard.self_ref.upgrade().unwrap(), 1059 after, 1060 )); 1061 } 1062 } 1063 1064 impl Drop for LockedVMA { 1065 fn drop(&mut self) { 1066 LOCKEDVMA_ID_ALLOCATOR.free(self.id); 1067 } 1068 } 1069 1070 /// VMA切分结果 1071 pub struct VMASplitResult { 1072 pub prev: Option<Arc<LockedVMA>>, 1073 pub middle: Arc<LockedVMA>, 1074 pub after: Option<Arc<LockedVMA>>, 1075 } 1076 1077 impl VMASplitResult { 1078 pub fn new( 1079 prev: Option<Arc<LockedVMA>>, 1080 middle: Arc<LockedVMA>, 1081 post: Option<Arc<LockedVMA>>, 1082 ) -> Self { 1083 Self { 1084 prev, 1085 middle, 1086 after: post, 1087 } 1088 } 1089 } 1090 1091 /// @brief 虚拟内存区域 1092 #[derive(Debug)] 1093 pub struct VMA { 1094 /// 虚拟内存区域对应的虚拟地址范围 1095 region: VirtRegion, 1096 /// 虚拟内存区域标志 1097 vm_flags: VmFlags, 1098 /// VMA内的页帧的标志 1099 flags: PageFlags<MMArch>, 1100 /// VMA内的页帧是否已经映射到页表 1101 mapped: bool, 1102 /// VMA所属的用户地址空间 1103 user_address_space: Option<Weak<AddressSpace>>, 1104 self_ref: Weak<LockedVMA>, 1105 1106 provider: Provider, 1107 } 1108 1109 impl core::hash::Hash for VMA { 1110 fn hash<H: Hasher>(&self, state: &mut H) { 1111 self.region.hash(state); 1112 self.flags.hash(state); 1113 self.mapped.hash(state); 1114 } 1115 } 1116 1117 /// 描述不同类型的内存提供者或资源 1118 #[derive(Debug)] 1119 pub enum Provider { 1120 Allocated, // TODO:其他 1121 } 1122 1123 #[allow(dead_code)] 1124 impl VMA { 1125 pub fn new( 1126 region: VirtRegion, 1127 vm_flags: VmFlags, 1128 flags: PageFlags<MMArch>, 1129 mapped: bool, 1130 ) -> Self { 1131 VMA { 1132 region, 1133 vm_flags, 1134 flags, 1135 mapped, 1136 user_address_space: None, 1137 self_ref: Weak::default(), 1138 provider: Provider::Allocated, 1139 } 1140 } 1141 1142 pub fn region(&self) -> &VirtRegion { 1143 return &self.region; 1144 } 1145 1146 pub fn vm_flags(&self) -> &VmFlags { 1147 return &self.vm_flags; 1148 } 1149 1150 pub fn set_vm_flags(&mut self, vm_flags: VmFlags) { 1151 self.vm_flags = vm_flags; 1152 } 1153 1154 pub fn set_region_size(&mut self, new_region_size: usize) { 1155 self.region.set_size(new_region_size); 1156 } 1157 1158 /// # 拷贝当前VMA的内容 1159 /// 1160 /// ### 安全性 1161 /// 1162 /// 由于这样操作可能由于错误的拷贝，导致内存泄露、内存重复释放等问题，所以需要小心使用。 1163 pub unsafe fn clone(&self) -> Self { 1164 return Self { 1165 region: self.region, 1166 vm_flags: self.vm_flags, 1167 flags: self.flags, 1168 mapped: self.mapped, 1169 user_address_space: self.user_address_space.clone(), 1170 self_ref: self.self_ref.clone(), 1171 provider: Provider::Allocated, 1172 }; 1173 } 1174 1175 #[inline(always)] 1176 pub fn flags(&self) -> PageFlags<MMArch> { 1177 return self.flags; 1178 } 1179 1180 pub fn pages(&self) -> VirtPageFrameIter { 1181 return VirtPageFrameIter::new( 1182 VirtPageFrame::new(self.region.start()), 1183 VirtPageFrame::new(self.region.end()), 1184 ); 1185 } 1186 1187 pub fn remap( 1188 &mut self, 1189 flags: PageFlags<MMArch>, 1190 mapper: &mut PageMapper, 1191 mut flusher: impl Flusher<MMArch>, 1192 ) -> Result<(), SystemError> { 1193 assert!(self.mapped); 1194 for page in self.region.pages() { 1195 // kdebug!("remap page {:?}", page.virt_address()); 1196 // 暂时要求所有的页帧都已经映射到页表 1197 // TODO: 引入Lazy Mapping, 通过缺页中断来映射页帧，这里就不必要求所有的页帧都已经映射到页表了 1198 let r = unsafe { 1199 mapper 1200 .remap(page.virt_address(), flags) 1201 .expect("Failed to remap, beacuse of some page is not mapped") 1202 }; 1203 // kdebug!("consume page {:?}", page.virt_address()); 1204 flusher.consume(r); 1205 // kdebug!("remap page {:?} done", page.virt_address()); 1206 } 1207 self.flags = flags; 1208 return Ok(()); 1209 } 1210 1211 /// 检查当前VMA是否可以拥有指定的标志位 1212 /// 1213 /// ## 参数 1214 /// 1215 /// - `prot_flags` 要检查的标志位 1216 pub fn can_have_flags(&self, prot_flags: ProtFlags) -> bool { 1217 let is_downgrade = (self.flags.has_write() || !prot_flags.contains(ProtFlags::PROT_WRITE)) 1218 && (self.flags.has_execute() || !prot_flags.contains(ProtFlags::PROT_EXEC)); 1219 1220 match self.provider { 1221 Provider::Allocated { .. } => true, 1222 1223 #[allow(unreachable_patterns)] 1224 _ => is_downgrade, 1225 } 1226 } 1227 1228 /// 把物理地址映射到虚拟地址 1229 /// 1230 /// @param phys 要映射的物理地址 1231 /// @param destination 要映射到的虚拟地址 1232 /// @param count 要映射的页帧数量 1233 /// @param flags 页面标志位 1234 /// @param mapper 页表映射器 1235 /// @param flusher 页表项刷新器 1236 /// 1237 /// @return 返回映射后的虚拟内存区域 1238 pub fn physmap( 1239 phys: PhysPageFrame, 1240 destination: VirtPageFrame, 1241 count: PageFrameCount, 1242 vm_flags: VmFlags, 1243 flags: PageFlags<MMArch>, 1244 mapper: &mut PageMapper, 1245 mut flusher: impl Flusher<MMArch>, 1246 ) -> Result<Arc<LockedVMA>, SystemError> { 1247 let mut cur_phy = phys; 1248 let mut cur_dest = destination; 1249 1250 for _ in 0..count.data() { 1251 // 将物理页帧映射到虚拟页帧 1252 let r = 1253 unsafe { mapper.map_phys(cur_dest.virt_address(), cur_phy.phys_address(), flags) } 1254 .expect("Failed to map phys, may be OOM error"); 1255 1256 // todo: 增加OOM处理 1257 1258 // 刷新TLB 1259 flusher.consume(r); 1260 1261 cur_phy = cur_phy.next(); 1262 cur_dest = cur_dest.next(); 1263 } 1264 1265 let r: Arc<LockedVMA> = LockedVMA::new(VMA { 1266 region: VirtRegion::new(destination.virt_address(), count.data() * MMArch::PAGE_SIZE), 1267 vm_flags, 1268 flags, 1269 mapped: true, 1270 user_address_space: None, 1271 self_ref: Weak::default(), 1272 provider: Provider::Allocated, 1273 }); 1274 1275 // 将VMA加入到anon_vma中 1276 let mut anon_vma_guard = page_manager_lock_irasave(); 1277 cur_phy = phys; 1278 for _ in 0..count.data() { 1279 let paddr = cur_phy.phys_address(); 1280 let page = anon_vma_guard.get_mut(&paddr); 1281 page.insert_vma(r.clone()); 1282 cur_phy = cur_phy.next(); 1283 } 1284 1285 return Ok(r); 1286 } 1287 1288 /// 从页分配器中分配一些物理页，并把它们映射到指定的虚拟地址，然后创建VMA 1289 /// 1290 /// @param destination 要映射到的虚拟地址 1291 /// @param count 要映射的页帧数量 1292 /// @param flags 页面标志位 1293 /// @param mapper 页表映射器 1294 /// @param flusher 页表项刷新器 1295 /// 1296 /// @return 返回映射后的虚拟内存区域 1297 pub fn zeroed( 1298 destination: VirtPageFrame, 1299 page_count: PageFrameCount, 1300 vm_flags: VmFlags, 1301 flags: PageFlags<MMArch>, 1302 mapper: &mut PageMapper, 1303 mut flusher: impl Flusher<MMArch>, 1304 ) -> Result<Arc<LockedVMA>, SystemError> { 1305 let mut cur_dest: VirtPageFrame = destination; 1306 // kdebug!( 1307 // "VMA::zeroed: page_count = {:?}, destination={destination:?}", 1308 // page_count 1309 // ); 1310 for _ in 0..page_count.data() { 1311 // kdebug!( 1312 // "VMA::zeroed: cur_dest={cur_dest:?}, vaddr = {:?}", 1313 // cur_dest.virt_address() 1314 // ); 1315 let r = unsafe { mapper.map(cur_dest.virt_address(), flags) } 1316 .expect("Failed to map zero, may be OOM error"); 1317 // todo: 增加OOM处理 1318 1319 // 稍后再刷新TLB，这里取消刷新 1320 flusher.consume(r); 1321 cur_dest = cur_dest.next(); 1322 } 1323 let r = LockedVMA::new(VMA { 1324 region: VirtRegion::new( 1325 destination.virt_address(), 1326 page_count.data() * MMArch::PAGE_SIZE, 1327 ), 1328 vm_flags, 1329 flags, 1330 mapped: true, 1331 user_address_space: None, 1332 self_ref: Weak::default(), 1333 provider: Provider::Allocated, 1334 }); 1335 drop(flusher); 1336 // kdebug!("VMA::zeroed: flusher dropped"); 1337 1338 // 清空这些内存并将VMA加入到anon_vma中 1339 let mut anon_vma_guard = page_manager_lock_irasave(); 1340 let virt_iter: VirtPageFrameIter = 1341 VirtPageFrameIter::new(destination, destination.add(page_count)); 1342 for frame in virt_iter { 1343 let paddr = mapper.translate(frame.virt_address()).unwrap().0; 1344 1345 // 将VMA加入到anon_vma 1346 let page = anon_vma_guard.get_mut(&paddr); 1347 page.insert_vma(r.clone()); 1348 1349 // 清空内存 1350 unsafe { 1351 let vaddr = MMArch::phys_2_virt(paddr).unwrap(); 1352 MMArch::write_bytes(vaddr, 0, MMArch::PAGE_SIZE); 1353 } 1354 } 1355 // kdebug!("VMA::zeroed: done"); 1356 return Ok(r); 1357 } 1358 } 1359 1360 impl Drop for VMA { 1361 fn drop(&mut self) { 1362 // 当VMA被释放时，需要确保它已经被从页表中解除映射 1363 assert!(!self.mapped, "VMA is still mapped"); 1364 } 1365 } 1366 1367 impl PartialEq for VMA { 1368 fn eq(&self, other: &Self) -> bool { 1369 return self.region == other.region; 1370 } 1371 } 1372 1373 impl Eq for VMA {} 1374 1375 impl PartialOrd for VMA { 1376 fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> { 1377 Some(self.cmp(other)) 1378 } 1379 } 1380 1381 impl Ord for VMA { 1382 fn cmp(&self, other: &Self) -> cmp::Ordering { 1383 return self.region.cmp(&other.region); 1384 } 1385 } 1386 1387 #[derive(Debug)] 1388 pub struct UserStack { 1389 // 栈底地址 1390 stack_bottom: VirtAddr, 1391 // 当前已映射的大小 1392 mapped_size: usize, 1393 /// 栈顶地址（这个值需要仔细确定！因为它可能不会实时与用户栈的真实栈顶保持一致！要小心！） 1394 current_sp: VirtAddr, 1395 } 1396 1397 impl UserStack { 1398 /// 默认的用户栈底地址 1399 pub const DEFAULT_USER_STACK_BOTTOM: VirtAddr = MMArch::USER_STACK_START; 1400 /// 默认的用户栈大小为8MB 1401 pub const DEFAULT_USER_STACK_SIZE: usize = 8 * 1024 * 1024; 1402 /// 用户栈的保护页数量 1403 pub const GUARD_PAGES_NUM: usize = 4; 1404 1405 /// 创建一个用户栈 1406 pub fn new( 1407 vm: &mut InnerAddressSpace, 1408 stack_bottom: Option<VirtAddr>, 1409 stack_size: usize, 1410 ) -> Result<Self, SystemError> { 1411 let stack_bottom = stack_bottom.unwrap_or(Self::DEFAULT_USER_STACK_BOTTOM); 1412 assert!(stack_bottom.check_aligned(MMArch::PAGE_SIZE)); 1413 1414 // 分配用户栈的保护页 1415 let guard_size = Self::GUARD_PAGES_NUM * MMArch::PAGE_SIZE; 1416 let actual_stack_bottom = stack_bottom - guard_size; 1417 1418 let mut prot_flags = ProtFlags::PROT_READ | ProtFlags::PROT_WRITE; 1419 let map_flags = 1420 MapFlags::MAP_PRIVATE | MapFlags::MAP_ANONYMOUS | MapFlags::MAP_FIXED_NOREPLACE; 1421 // kdebug!( 1422 // "map anonymous stack: {:?} {}", 1423 // actual_stack_bottom, 1424 // guard_size 1425 // ); 1426 vm.map_anonymous( 1427 actual_stack_bottom, 1428 guard_size, 1429 prot_flags, 1430 map_flags, 1431 false, 1432 )?; 1433 // test_buddy(); 1434 // 设置保护页只读 1435 prot_flags.remove(ProtFlags::PROT_WRITE); 1436 // kdebug!( 1437 // "to mprotect stack guard pages: {:?} {}", 1438 // actual_stack_bottom, 1439 // guard_size 1440 // ); 1441 vm.mprotect( 1442 VirtPageFrame::new(actual_stack_bottom), 1443 PageFrameCount::new(Self::GUARD_PAGES_NUM), 1444 prot_flags, 1445 )?; 1446 1447 // kdebug!( 1448 // "mprotect stack guard pages done: {:?} {}", 1449 // actual_stack_bottom, 1450 // guard_size 1451 // ); 1452 1453 let mut user_stack = UserStack { 1454 stack_bottom: actual_stack_bottom, 1455 mapped_size: guard_size, 1456 current_sp: actual_stack_bottom - guard_size, 1457 }; 1458 1459 // kdebug!("extend user stack: {:?} {}", stack_bottom, stack_size); 1460 // 分配用户栈 1461 user_stack.initial_extend(vm, stack_size)?; 1462 // kdebug!("user stack created: {:?} {}", stack_bottom, stack_size); 1463 return Ok(user_stack); 1464 } 1465 1466 fn initial_extend( 1467 &mut self, 1468 vm: &mut InnerAddressSpace, 1469 mut bytes: usize, 1470 ) -> Result<(), SystemError> { 1471 let prot_flags = ProtFlags::PROT_READ | ProtFlags::PROT_WRITE | ProtFlags::PROT_EXEC; 1472 let map_flags = MapFlags::MAP_PRIVATE | MapFlags::MAP_ANONYMOUS; 1473 1474 bytes = page_align_up(bytes); 1475 self.mapped_size += bytes; 1476 1477 vm.map_anonymous( 1478 self.stack_bottom - self.mapped_size, 1479 bytes, 1480 prot_flags, 1481 map_flags, 1482 false, 1483 )?; 1484 1485 return Ok(()); 1486 } 1487 1488 /// 扩展用户栈 1489 /// 1490 /// ## 参数 1491 /// 1492 /// - `vm` 用户地址空间结构体 1493 /// - `bytes` 要扩展的字节数 1494 /// 1495 /// ## 返回值 1496 /// 1497 /// - **Ok(())** 扩展成功 1498 /// - **Err(SystemError)** 扩展失败 1499 #[allow(dead_code)] 1500 pub fn extend( 1501 &mut self, 1502 vm: &mut RwLockWriteGuard<InnerAddressSpace>, 1503 mut bytes: usize, 1504 ) -> Result<(), SystemError> { 1505 let prot_flags = ProtFlags::PROT_READ | ProtFlags::PROT_WRITE | ProtFlags::PROT_EXEC; 1506 let map_flags = MapFlags::MAP_PRIVATE | MapFlags::MAP_ANONYMOUS; 1507 1508 bytes = page_align_up(bytes); 1509 self.mapped_size += bytes; 1510 1511 vm.map_anonymous( 1512 self.stack_bottom - self.mapped_size, 1513 bytes, 1514 prot_flags, 1515 map_flags, 1516 false, 1517 )?; 1518 1519 return Ok(()); 1520 } 1521 1522 /// 获取栈顶地址 1523 /// 1524 /// 请注意，如果用户栈的栈顶地址发生变化，这个值可能不会实时更新！ 1525 pub fn sp(&self) -> VirtAddr { 1526 return self.current_sp; 1527 } 1528 1529 pub unsafe fn set_sp(&mut self, sp: VirtAddr) { 1530 self.current_sp = sp; 1531 } 1532 1533 /// 仅仅克隆用户栈的信息，不会克隆用户栈的内容/映射 1534 pub unsafe fn clone_info_only(&self) -> Self { 1535 return Self { 1536 stack_bottom: self.stack_bottom, 1537 mapped_size: self.mapped_size, 1538 current_sp: self.current_sp, 1539 }; 1540 } 1541 1542 /// 获取当前用户栈的大小（不包括保护页） 1543 pub fn stack_size(&self) -> usize { 1544 return self.mapped_size - Self::GUARD_PAGES_NUM * MMArch::PAGE_SIZE; 1545 } 1546 } 1547