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, 26 spinlock::{SpinLock, SpinLockGuard}, 27 }, 28 mm::page::page_manager_lock_irqsave, 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::{MadvFlags, 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 // debug!("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 unsafe { 164 new_guard 165 .user_mapper 166 .clone_from(&mut self.user_mapper, MMArch::PAGE_FAULT_ENABLED) 167 }; 168 169 // 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） 170 unsafe { 171 new_guard.user_stack = Some(self.user_stack.as_ref().unwrap().clone_info_only()); 172 } 173 let _current_stack_size = self.user_stack.as_ref().unwrap().stack_size(); 174 175 // 拷贝空洞 176 new_guard.mappings.vm_holes = self.mappings.vm_holes.clone(); 177 178 for vma in self.mappings.vmas.iter() { 179 // TODO: 增加对VMA是否为文件映射的判断，如果是的话，就跳过 180 181 let vma_guard: SpinLockGuard<'_, VMA> = vma.lock(); 182 183 // 仅拷贝VMA信息并添加反向映射，因为UserMapper克隆时已经分配了新的物理页 184 let new_vma = LockedVMA::new(vma_guard.clone_info_only()); 185 new_guard.mappings.vmas.insert(new_vma.clone()); 186 // debug!("new vma: {:x?}", new_vma); 187 let new_vma_guard = new_vma.lock(); 188 let new_mapper = &new_guard.user_mapper.utable; 189 let mut anon_vma_guard = page_manager_lock_irqsave(); 190 for page in new_vma_guard.pages().map(|p| p.virt_address()) { 191 if let Some((paddr, _)) = new_mapper.translate(page) { 192 let page = anon_vma_guard.get_mut(&paddr); 193 page.insert_vma(new_vma.clone()); 194 } 195 } 196 197 drop(anon_vma_guard); 198 drop(vma_guard); 199 drop(new_vma_guard); 200 } 201 drop(new_guard); 202 drop(irq_guard); 203 return Ok(new_addr_space); 204 } 205 206 /// 拓展用户栈 207 /// ## 参数 208 /// 209 /// - `bytes`: 拓展大小 210 #[allow(dead_code)] 211 pub fn extend_stack(&mut self, mut bytes: usize) -> Result<(), SystemError> { 212 // debug!("extend user stack"); 213 let prot_flags = ProtFlags::PROT_READ | ProtFlags::PROT_WRITE | ProtFlags::PROT_EXEC; 214 let map_flags = MapFlags::MAP_PRIVATE | MapFlags::MAP_ANONYMOUS | MapFlags::MAP_GROWSDOWN; 215 let stack = self.user_stack.as_mut().unwrap(); 216 217 bytes = page_align_up(bytes); 218 stack.mapped_size += bytes; 219 let len = stack.stack_bottom - stack.mapped_size; 220 self.map_anonymous(len, bytes, prot_flags, map_flags, false, false)?; 221 return Ok(()); 222 } 223 224 /// 判断当前的地址空间是否是当前进程的地址空间 225 #[inline] 226 pub fn is_current(&self) -> bool { 227 return self.user_mapper.utable.is_current(); 228 } 229 230 /// 进行匿名页映射 231 /// 232 /// ## 参数 233 /// 234 /// - `start_vaddr`：映射的起始地址 235 /// - `len`：映射的长度 236 /// - `prot_flags`：保护标志 237 /// - `map_flags`：映射标志 238 /// - `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 239 /// - `allocate_at_once`：是否立即分配物理空间 240 /// 241 /// ## 返回 242 /// 243 /// 返回映射的起始虚拟页帧 244 pub fn map_anonymous( 245 &mut self, 246 start_vaddr: VirtAddr, 247 len: usize, 248 prot_flags: ProtFlags, 249 map_flags: MapFlags, 250 round_to_min: bool, 251 allocate_at_once: bool, 252 ) -> Result<VirtPageFrame, SystemError> { 253 let allocate_at_once = if MMArch::PAGE_FAULT_ENABLED { 254 allocate_at_once 255 } else { 256 true 257 }; 258 // 用于对齐hint的函数 259 let round_hint_to_min = |hint: VirtAddr| { 260 // 先把hint向下对齐到页边界 261 let addr = hint.data() & (!MMArch::PAGE_OFFSET_MASK); 262 // debug!("map_anonymous: hint = {:?}, addr = {addr:#x}", hint); 263 // 如果hint不是0，且hint小于DEFAULT_MMAP_MIN_ADDR，则对齐到DEFAULT_MMAP_MIN_ADDR 264 if (addr != 0) && round_to_min && (addr < DEFAULT_MMAP_MIN_ADDR) { 265 Some(VirtAddr::new(page_align_up(DEFAULT_MMAP_MIN_ADDR))) 266 } else if addr == 0 { 267 None 268 } else { 269 Some(VirtAddr::new(addr)) 270 } 271 }; 272 // debug!("map_anonymous: start_vaddr = {:?}", start_vaddr); 273 // debug!("map_anonymous: len(no align) = {}", len); 274 275 let len = page_align_up(len); 276 277 let vm_flags = VmFlags::from(prot_flags) 278 | VmFlags::from(map_flags) 279 | VmFlags::VM_MAYREAD 280 | VmFlags::VM_MAYWRITE 281 | VmFlags::VM_MAYEXEC; 282 283 // debug!("map_anonymous: len = {}", len); 284 285 let start_page: VirtPageFrame = if allocate_at_once { 286 self.mmap( 287 round_hint_to_min(start_vaddr), 288 PageFrameCount::from_bytes(len).unwrap(), 289 prot_flags, 290 map_flags, 291 move |page, count, flags, mapper, flusher| { 292 VMA::zeroed(page, count, vm_flags, flags, mapper, flusher) 293 }, 294 )? 295 } else { 296 self.mmap( 297 round_hint_to_min(start_vaddr), 298 PageFrameCount::from_bytes(len).unwrap(), 299 prot_flags, 300 map_flags, 301 move |page, count, flags, _mapper, _flusher| { 302 Ok(LockedVMA::new(VMA::new( 303 VirtRegion::new(page.virt_address(), count.data() * MMArch::PAGE_SIZE), 304 vm_flags, 305 flags, 306 false, 307 ))) 308 }, 309 )? 310 }; 311 312 return Ok(start_page); 313 } 314 315 /// 向进程的地址空间映射页面 316 /// 317 /// # 参数 318 /// 319 /// - `addr`：映射的起始地址，如果为`None`，则由内核自动分配 320 /// - `page_count`：映射的页面数量 321 /// - `prot_flags`：保护标志 322 /// - `map_flags`：映射标志 323 /// - `map_func`：映射函数，用于创建VMA 324 /// 325 /// # Returns 326 /// 327 /// 返回映射的起始虚拟页帧 328 /// 329 /// # Errors 330 /// 331 /// - `EINVAL`：参数错误 332 pub fn mmap< 333 F: FnOnce( 334 VirtPageFrame, 335 PageFrameCount, 336 PageFlags<MMArch>, 337 &mut PageMapper, 338 &mut dyn Flusher<MMArch>, 339 ) -> Result<Arc<LockedVMA>, SystemError>, 340 >( 341 &mut self, 342 addr: Option<VirtAddr>, 343 page_count: PageFrameCount, 344 prot_flags: ProtFlags, 345 map_flags: MapFlags, 346 map_func: F, 347 ) -> Result<VirtPageFrame, SystemError> { 348 if page_count == PageFrameCount::new(0) { 349 return Err(SystemError::EINVAL); 350 } 351 // debug!("mmap: addr: {addr:?}, page_count: {page_count:?}, prot_flags: {prot_flags:?}, map_flags: {map_flags:?}"); 352 353 // 找到未使用的区域 354 let region = match addr { 355 Some(vaddr) => { 356 self.mappings 357 .find_free_at(self.mmap_min, vaddr, page_count.bytes(), map_flags)? 358 } 359 None => self 360 .mappings 361 .find_free(self.mmap_min, page_count.bytes()) 362 .ok_or(SystemError::ENOMEM)?, 363 }; 364 365 let page = VirtPageFrame::new(region.start()); 366 367 // debug!("mmap: page: {:?}, region={region:?}", page.virt_address()); 368 369 compiler_fence(Ordering::SeqCst); 370 let (mut active, mut inactive); 371 let flusher = if self.is_current() { 372 active = PageFlushAll::new(); 373 &mut active as &mut dyn Flusher<MMArch> 374 } else { 375 inactive = InactiveFlusher::new(); 376 &mut inactive as &mut dyn Flusher<MMArch> 377 }; 378 compiler_fence(Ordering::SeqCst); 379 // 映射页面，并将VMA插入到地址空间的VMA列表中 380 self.mappings.insert_vma(map_func( 381 page, 382 page_count, 383 PageFlags::from_prot_flags(prot_flags, true), 384 &mut self.user_mapper.utable, 385 flusher, 386 )?); 387 388 return Ok(page); 389 } 390 391 /// 重映射内存区域 392 /// 393 /// # 参数 394 /// 395 /// - `old_vaddr`：原映射的起始地址 396 /// - `old_len`：原映射的长度 397 /// - `new_len`：重新映射的长度 398 /// - `mremap_flags`：重映射标志 399 /// - `new_vaddr`：重新映射的起始地址 400 /// - `vm_flags`：旧内存区域标志 401 /// 402 /// # Returns 403 /// 404 /// 返回重映射的起始虚拟页帧地址 405 /// 406 /// # Errors 407 /// 408 /// - `EINVAL`：参数错误 409 pub fn mremap( 410 &mut self, 411 old_vaddr: VirtAddr, 412 old_len: usize, 413 new_len: usize, 414 mremap_flags: MremapFlags, 415 new_vaddr: VirtAddr, 416 vm_flags: VmFlags, 417 ) -> Result<VirtAddr, SystemError> { 418 // 检查新内存地址是否对齐 419 if !new_vaddr.check_aligned(MMArch::PAGE_SIZE) { 420 return Err(SystemError::EINVAL); 421 } 422 423 // 检查新、旧内存区域是否冲突 424 let old_region = VirtRegion::new(old_vaddr, old_len); 425 let new_region = VirtRegion::new(new_vaddr, new_len); 426 if old_region.collide(&new_region) { 427 return Err(SystemError::EINVAL); 428 } 429 430 // 初始化映射标志 431 let mut map_flags: MapFlags = vm_flags.into(); 432 // 初始化内存区域保护标志 433 let prot_flags: ProtFlags = vm_flags.into(); 434 435 // 取消新内存区域的原映射 436 if mremap_flags.contains(MremapFlags::MREMAP_FIXED) { 437 map_flags |= MapFlags::MAP_FIXED; 438 let start_page = VirtPageFrame::new(new_vaddr); 439 let page_count = PageFrameCount::from_bytes(new_len).unwrap(); 440 self.munmap(start_page, page_count)?; 441 } 442 443 // 获取映射后的新内存页面 444 let new_page = self.map_anonymous(new_vaddr, new_len, prot_flags, map_flags, true, true)?; 445 let new_page_vaddr = new_page.virt_address(); 446 447 // 拷贝旧内存区域内容到新内存区域 448 let old_buffer_reader = 449 UserBufferReader::new(old_vaddr.data() as *const u8, old_len, true)?; 450 let old_buf: &[u8] = old_buffer_reader.read_from_user(0)?; 451 let mut new_buffer_writer = 452 UserBufferWriter::new(new_page_vaddr.data() as *mut u8, new_len, true)?; 453 let new_buf: &mut [u8] = new_buffer_writer.buffer(0)?; 454 let len = old_buf.len().min(new_buf.len()); 455 new_buf[..len].copy_from_slice(&old_buf[..len]); 456 457 return Ok(new_page_vaddr); 458 } 459 460 /// 取消进程的地址空间中的映射 461 /// 462 /// # 参数 463 /// 464 /// - `start_page`：起始页帧 465 /// - `page_count`：取消映射的页帧数量 466 /// 467 /// # Errors 468 /// 469 /// - `EINVAL`：参数错误 470 /// - `ENOMEM`：内存不足 471 pub fn munmap( 472 &mut self, 473 start_page: VirtPageFrame, 474 page_count: PageFrameCount, 475 ) -> Result<(), SystemError> { 476 let to_unmap = VirtRegion::new(start_page.virt_address(), page_count.bytes()); 477 let mut flusher: PageFlushAll<MMArch> = PageFlushAll::new(); 478 479 let regions: Vec<Arc<LockedVMA>> = self.mappings.conflicts(to_unmap).collect::<Vec<_>>(); 480 481 for r in regions { 482 let r = r.lock().region; 483 let r = self.mappings.remove_vma(&r).unwrap(); 484 let intersection = r.lock().region().intersect(&to_unmap).unwrap(); 485 let split_result = r.extract(intersection, &self.user_mapper.utable).unwrap(); 486 487 // TODO: 当引入后备页映射后，这里需要增加通知文件的逻辑 488 489 if let Some(before) = split_result.prev { 490 // 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 491 self.mappings.insert_vma(before); 492 } 493 494 if let Some(after) = split_result.after { 495 // 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 496 self.mappings.insert_vma(after); 497 } 498 499 r.unmap(&mut self.user_mapper.utable, &mut flusher); 500 } 501 502 // TODO: 当引入后备页映射后，这里需要增加通知文件的逻辑 503 504 return Ok(()); 505 } 506 507 pub fn mprotect( 508 &mut self, 509 start_page: VirtPageFrame, 510 page_count: PageFrameCount, 511 prot_flags: ProtFlags, 512 ) -> Result<(), SystemError> { 513 // debug!( 514 // "mprotect: start_page: {:?}, page_count: {:?}, prot_flags:{prot_flags:?}", 515 // start_page, 516 // page_count 517 // ); 518 let (mut active, mut inactive); 519 let mut flusher = if self.is_current() { 520 active = PageFlushAll::new(); 521 &mut active as &mut dyn Flusher<MMArch> 522 } else { 523 inactive = InactiveFlusher::new(); 524 &mut inactive as &mut dyn Flusher<MMArch> 525 }; 526 527 let mapper = &mut self.user_mapper.utable; 528 let region = VirtRegion::new(start_page.virt_address(), page_count.bytes()); 529 // debug!("mprotect: region: {:?}", region); 530 531 let regions = self.mappings.conflicts(region).collect::<Vec<_>>(); 532 // debug!("mprotect: regions: {:?}", regions); 533 534 for r in regions { 535 // debug!("mprotect: r: {:?}", r); 536 let r = *r.lock().region(); 537 let r = self.mappings.remove_vma(&r).unwrap(); 538 539 let intersection = r.lock().region().intersect(®ion).unwrap(); 540 let split_result = r 541 .extract(intersection, mapper) 542 .expect("Failed to extract VMA"); 543 544 if let Some(before) = split_result.prev { 545 self.mappings.insert_vma(before); 546 } 547 if let Some(after) = split_result.after { 548 self.mappings.insert_vma(after); 549 } 550 551 let mut r_guard = r.lock(); 552 // 如果VMA的保护标志不允许指定的修改，则返回错误 553 if !r_guard.can_have_flags(prot_flags) { 554 drop(r_guard); 555 self.mappings.insert_vma(r.clone()); 556 return Err(SystemError::EACCES); 557 } 558 559 r_guard.set_vm_flags(VmFlags::from(prot_flags)); 560 561 let new_flags: PageFlags<MMArch> = r_guard 562 .flags() 563 .set_execute(prot_flags.contains(ProtFlags::PROT_EXEC)) 564 .set_write(prot_flags.contains(ProtFlags::PROT_WRITE)); 565 566 r_guard.remap(new_flags, mapper, &mut flusher)?; 567 drop(r_guard); 568 self.mappings.insert_vma(r); 569 } 570 571 return Ok(()); 572 } 573 574 pub fn madvise( 575 &mut self, 576 start_page: VirtPageFrame, 577 page_count: PageFrameCount, 578 behavior: MadvFlags, 579 ) -> Result<(), SystemError> { 580 let (mut active, mut inactive); 581 let mut flusher = if self.is_current() { 582 active = PageFlushAll::new(); 583 &mut active as &mut dyn Flusher<MMArch> 584 } else { 585 inactive = InactiveFlusher::new(); 586 &mut inactive as &mut dyn Flusher<MMArch> 587 }; 588 589 let mapper = &mut self.user_mapper.utable; 590 591 let region = VirtRegion::new(start_page.virt_address(), page_count.bytes()); 592 let regions = self.mappings.conflicts(region).collect::<Vec<_>>(); 593 594 for r in regions { 595 let r = *r.lock().region(); 596 let r = self.mappings.remove_vma(&r).unwrap(); 597 598 let intersection = r.lock().region().intersect(®ion).unwrap(); 599 let split_result = r 600 .extract(intersection, mapper) 601 .expect("Failed to extract VMA"); 602 603 if let Some(before) = split_result.prev { 604 self.mappings.insert_vma(before); 605 } 606 if let Some(after) = split_result.after { 607 self.mappings.insert_vma(after); 608 } 609 r.do_madvise(behavior, mapper, &mut flusher)?; 610 self.mappings.insert_vma(r); 611 } 612 Ok(()) 613 } 614 615 /// 创建新的用户栈 616 /// 617 /// ## 参数 618 /// 619 /// - `size`：栈的大小 620 pub fn new_user_stack(&mut self, size: usize) -> Result<(), SystemError> { 621 assert!(self.user_stack.is_none(), "User stack already exists"); 622 let stack = UserStack::new(self, None, size)?; 623 self.user_stack = Some(stack); 624 return Ok(()); 625 } 626 627 #[inline(always)] 628 pub fn user_stack_mut(&mut self) -> Option<&mut UserStack> { 629 return self.user_stack.as_mut(); 630 } 631 632 /// 取消用户空间内的所有映射 633 pub unsafe fn unmap_all(&mut self) { 634 let mut flusher: PageFlushAll<MMArch> = PageFlushAll::new(); 635 for vma in self.mappings.iter_vmas() { 636 if vma.mapped() { 637 vma.unmap(&mut self.user_mapper.utable, &mut flusher); 638 } 639 } 640 } 641 642 /// 设置进程的堆的内存空间 643 /// 644 /// ## 参数 645 /// 646 /// - `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 647 /// 648 /// ## 返回值 649 /// 650 /// 返回旧的堆的结束地址 651 pub unsafe fn set_brk(&mut self, new_brk: VirtAddr) -> Result<VirtAddr, SystemError> { 652 assert!(new_brk.check_aligned(MMArch::PAGE_SIZE)); 653 654 if !new_brk.check_user() || new_brk < self.brk_start { 655 return Err(SystemError::EFAULT); 656 } 657 658 let old_brk = self.brk; 659 660 if new_brk > self.brk { 661 let len = new_brk - self.brk; 662 let prot_flags = ProtFlags::PROT_READ | ProtFlags::PROT_WRITE | ProtFlags::PROT_EXEC; 663 let map_flags = MapFlags::MAP_PRIVATE | MapFlags::MAP_ANONYMOUS | MapFlags::MAP_FIXED; 664 self.map_anonymous(old_brk, len, prot_flags, map_flags, true, false)?; 665 666 self.brk = new_brk; 667 return Ok(old_brk); 668 } else { 669 let unmap_len = self.brk - new_brk; 670 let unmap_start = new_brk; 671 if unmap_len == 0 { 672 return Ok(old_brk); 673 } 674 self.munmap( 675 VirtPageFrame::new(unmap_start), 676 PageFrameCount::from_bytes(unmap_len).unwrap(), 677 )?; 678 self.brk = new_brk; 679 return Ok(old_brk); 680 } 681 } 682 683 pub unsafe fn sbrk(&mut self, incr: isize) -> Result<VirtAddr, SystemError> { 684 if incr == 0 { 685 return Ok(self.brk); 686 } 687 688 let new_brk = if incr > 0 { 689 self.brk + incr as usize 690 } else { 691 self.brk - incr.unsigned_abs() 692 }; 693 694 let new_brk = VirtAddr::new(page_align_up(new_brk.data())); 695 696 return self.set_brk(new_brk); 697 } 698 } 699 700 impl Drop for InnerAddressSpace { 701 fn drop(&mut self) { 702 unsafe { 703 self.unmap_all(); 704 } 705 } 706 } 707 708 #[derive(Debug, Hash)] 709 pub struct UserMapper { 710 pub utable: PageMapper, 711 } 712 713 impl UserMapper { 714 pub fn new(utable: PageMapper) -> Self { 715 return Self { utable }; 716 } 717 718 /// 拷贝用户空间映射 719 /// ## 参数 720 /// 721 /// - `umapper`: 要拷贝的用户空间 722 /// - `copy_on_write`: 是否写时复制 723 pub unsafe fn clone_from(&mut self, umapper: &mut Self, copy_on_write: bool) { 724 self.utable 725 .clone_user_mapping(&mut umapper.utable, copy_on_write); 726 } 727 } 728 729 impl Drop for UserMapper { 730 fn drop(&mut self) { 731 if self.utable.is_current() { 732 // 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 733 unsafe { MMArch::set_table(PageTableKind::User, MMArch::initial_page_table()) } 734 } 735 // 释放用户空间顶层页表占用的页帧 736 // 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 737 unsafe { 738 deallocate_page_frames( 739 PhysPageFrame::new(self.utable.table().phys()), 740 PageFrameCount::new(1), 741 &mut page_manager_lock_irqsave(), 742 ) 743 }; 744 } 745 } 746 747 /// 用户空间映射信息 748 #[derive(Debug)] 749 pub struct UserMappings { 750 /// 当前用户空间的虚拟内存区域 751 vmas: HashSet<Arc<LockedVMA>>, 752 /// 当前用户空间的VMA空洞 753 vm_holes: BTreeMap<VirtAddr, usize>, 754 } 755 756 impl UserMappings { 757 pub fn new() -> Self { 758 return Self { 759 vmas: HashSet::new(), 760 vm_holes: core::iter::once((VirtAddr::new(0), MMArch::USER_END_VADDR.data())) 761 .collect::<BTreeMap<_, _>>(), 762 }; 763 } 764 765 /// 判断当前进程的VMA内，是否有包含指定的虚拟地址的VMA。 766 /// 767 /// 如果有，返回包含指定虚拟地址的VMA的Arc指针，否则返回None。 768 #[allow(dead_code)] 769 pub fn contains(&self, vaddr: VirtAddr) -> Option<Arc<LockedVMA>> { 770 for v in self.vmas.iter() { 771 let guard = v.lock(); 772 if guard.region.contains(vaddr) { 773 return Some(v.clone()); 774 } 775 } 776 return None; 777 } 778 779 /// 向下寻找距离虚拟地址最近的VMA 780 /// ## 参数 781 /// 782 /// - `vaddr`: 虚拟地址 783 /// 784 /// ## 返回值 785 /// - Some(Arc<LockedVMA>): 虚拟地址所在的或最近的下一个VMA 786 /// - None: 未找到VMA 787 #[allow(dead_code)] 788 pub fn find_nearest(&self, vaddr: VirtAddr) -> Option<Arc<LockedVMA>> { 789 let mut nearest: Option<Arc<LockedVMA>> = None; 790 for v in self.vmas.iter() { 791 let guard = v.lock(); 792 if guard.region.contains(vaddr) { 793 return Some(v.clone()); 794 } 795 if guard.region.start > vaddr 796 && if let Some(ref nearest) = nearest { 797 guard.region.start < nearest.lock().region.start 798 } else { 799 true 800 } 801 { 802 nearest = Some(v.clone()); 803 } 804 } 805 return nearest; 806 } 807 808 /// 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。 809 pub fn conflicts(&self, request: VirtRegion) -> impl Iterator<Item = Arc<LockedVMA>> + '_ { 810 let r = self 811 .vmas 812 .iter() 813 .filter(move |v| v.lock().region.intersect(&request).is_some()) 814 .cloned(); 815 return r; 816 } 817 818 /// 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。 819 /// 820 /// @param min_vaddr 最小的起始地址 821 /// @param size 请求的大小 822 /// 823 /// @return 如果找到了，返回虚拟内存范围，否则返回None 824 pub fn find_free(&self, min_vaddr: VirtAddr, size: usize) -> Option<VirtRegion> { 825 let _vaddr = min_vaddr; 826 let mut iter = self 827 .vm_holes 828 .iter() 829 .skip_while(|(hole_vaddr, hole_size)| hole_vaddr.add(**hole_size) <= min_vaddr); 830 831 let (hole_vaddr, size) = iter.find(|(hole_vaddr, hole_size)| { 832 // 计算当前空洞的可用大小 833 let available_size: usize = 834 if hole_vaddr <= &&min_vaddr && min_vaddr <= hole_vaddr.add(**hole_size) { 835 **hole_size - (min_vaddr - **hole_vaddr) 836 } else { 837 **hole_size 838 }; 839 840 size <= available_size 841 })?; 842 843 // 创建一个新的虚拟内存范围。 844 let region = VirtRegion::new(cmp::max(*hole_vaddr, min_vaddr), *size); 845 846 return Some(region); 847 } 848 849 pub fn find_free_at( 850 &self, 851 min_vaddr: VirtAddr, 852 vaddr: VirtAddr, 853 size: usize, 854 flags: MapFlags, 855 ) -> Result<VirtRegion, SystemError> { 856 // 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。 857 if vaddr == VirtAddr::new(0) { 858 return self.find_free(min_vaddr, size).ok_or(SystemError::ENOMEM); 859 } 860 861 // 如果指定了地址，那么就检查指定的地址是否可用。 862 863 let requested = VirtRegion::new(vaddr, size); 864 865 if requested.end() >= MMArch::USER_END_VADDR || !vaddr.check_aligned(MMArch::PAGE_SIZE) { 866 return Err(SystemError::EINVAL); 867 } 868 869 if let Some(_x) = self.conflicts(requested).next() { 870 if flags.contains(MapFlags::MAP_FIXED_NOREPLACE) { 871 // 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 872 return Err(SystemError::EEXIST); 873 } 874 875 if flags.contains(MapFlags::MAP_FIXED) { 876 // todo: 支持MAP_FIXED标志对已有的VMA进行覆盖 877 return Err(SystemError::ENOSYS); 878 } 879 880 // 如果没有指定MAP_FIXED标志，那么就对地址做修正 881 let requested = self.find_free(min_vaddr, size).ok_or(SystemError::ENOMEM)?; 882 return Ok(requested); 883 } 884 885 return Ok(requested); 886 } 887 888 /// 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。 889 /// 该函数会修改vm_holes中的空洞信息。 890 /// 891 /// @param region 要保留的区域 892 /// 893 /// 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。 894 fn reserve_hole(&mut self, region: &VirtRegion) { 895 let prev_hole: Option<(&VirtAddr, &mut usize)> = 896 self.vm_holes.range_mut(..=region.start()).next_back(); 897 898 if let Some((prev_hole_vaddr, prev_hole_size)) = prev_hole { 899 let prev_hole_end = prev_hole_vaddr.add(*prev_hole_size); 900 901 if prev_hole_end > region.start() { 902 // 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。 903 *prev_hole_size = region.start().data() - prev_hole_vaddr.data(); 904 } 905 906 if prev_hole_end > region.end() { 907 // 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。 908 self.vm_holes 909 .insert(region.end(), prev_hole_end - region.end()); 910 } 911 } 912 } 913 914 /// 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。 915 /// 该函数会修改vm_holes中的空洞信息。 916 fn unreserve_hole(&mut self, region: &VirtRegion) { 917 // 如果将要插入的空洞与后一个空洞相邻，那么就需要合并。 918 let next_hole_size: Option<usize> = self.vm_holes.remove(®ion.end()); 919 920 if let Some((_prev_hole_vaddr, prev_hole_size)) = self 921 .vm_holes 922 .range_mut(..region.start()) 923 .next_back() 924 .filter(|(offset, size)| offset.data() + **size == region.start().data()) 925 { 926 *prev_hole_size += region.size() + next_hole_size.unwrap_or(0); 927 } else { 928 self.vm_holes 929 .insert(region.start(), region.size() + next_hole_size.unwrap_or(0)); 930 } 931 } 932 933 /// 在当前进程的映射关系中，插入一个新的VMA。 934 pub fn insert_vma(&mut self, vma: Arc<LockedVMA>) { 935 let region = vma.lock().region; 936 // 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。 937 assert!(self.conflicts(region).next().is_none()); 938 self.reserve_hole(®ion); 939 940 self.vmas.insert(vma); 941 } 942 943 /// @brief 删除一个VMA，并把对应的地址空间加入空洞中。 944 /// 945 /// 这里不会取消VMA对应的地址的映射 946 /// 947 /// @param region 要删除的VMA所在的地址范围 948 /// 949 /// @return 如果成功删除了VMA，则返回被删除的VMA，否则返回None 950 /// 如果没有可以删除的VMA，则不会执行删除操作，并报告失败。 951 pub fn remove_vma(&mut self, region: &VirtRegion) -> Option<Arc<LockedVMA>> { 952 // 请注意，由于这里会对每个VMA加锁，因此性能很低 953 let vma: Arc<LockedVMA> = self 954 .vmas 955 .drain_filter(|vma| vma.lock().region == *region) 956 .next()?; 957 self.unreserve_hole(region); 958 959 return Some(vma); 960 } 961 962 /// @brief Get the iterator of all VMAs in this process. 963 pub fn iter_vmas(&self) -> hashbrown::hash_set::Iter<Arc<LockedVMA>> { 964 return self.vmas.iter(); 965 } 966 } 967 968 impl Default for UserMappings { 969 fn default() -> Self { 970 return Self::new(); 971 } 972 } 973 974 /// 加了锁的VMA 975 /// 976 /// 备注：进行性能测试，看看SpinLock和RwLock哪个更快。 977 #[derive(Debug)] 978 pub struct LockedVMA { 979 /// 用于计算哈希值，避免总是获取vma锁来计算哈希值 980 id: usize, 981 vma: SpinLock<VMA>, 982 } 983 984 impl core::hash::Hash for LockedVMA { 985 fn hash<H: Hasher>(&self, state: &mut H) { 986 self.id.hash(state); 987 } 988 } 989 990 impl PartialEq for LockedVMA { 991 fn eq(&self, other: &Self) -> bool { 992 self.id.eq(&other.id) 993 } 994 } 995 996 impl Eq for LockedVMA {} 997 998 #[allow(dead_code)] 999 impl LockedVMA { 1000 pub fn new(vma: VMA) -> Arc<Self> { 1001 let r = Arc::new(Self { 1002 id: LOCKEDVMA_ID_ALLOCATOR.alloc().unwrap(), 1003 vma: SpinLock::new(vma), 1004 }); 1005 r.vma.lock().self_ref = Arc::downgrade(&r); 1006 return r; 1007 } 1008 1009 pub fn id(&self) -> usize { 1010 self.id 1011 } 1012 1013 pub fn lock(&self) -> SpinLockGuard<VMA> { 1014 return self.vma.lock(); 1015 } 1016 1017 /// 调整当前VMA的页面的标志位 1018 /// 1019 /// TODO：增加调整虚拟页映射的物理地址的功能 1020 /// 1021 /// @param flags 新的标志位 1022 /// @param mapper 页表映射器 1023 /// @param flusher 页表项刷新器 1024 /// 1025 pub fn remap( 1026 &self, 1027 flags: PageFlags<MMArch>, 1028 mapper: &mut PageMapper, 1029 mut flusher: impl Flusher<MMArch>, 1030 ) -> Result<(), SystemError> { 1031 let mut guard = self.lock(); 1032 for page in guard.region.pages() { 1033 // 暂时要求所有的页帧都已经映射到页表 1034 // 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 1035 let r = unsafe { 1036 mapper 1037 .remap(page.virt_address(), flags) 1038 .expect("Failed to remap, beacuse of some page is not mapped") 1039 }; 1040 flusher.consume(r); 1041 } 1042 guard.flags = flags; 1043 return Ok(()); 1044 } 1045 1046 pub fn unmap(&self, mapper: &mut PageMapper, mut flusher: impl Flusher<MMArch>) { 1047 // todo: 如果当前vma与文件相关，完善文件相关的逻辑 1048 1049 let mut guard = self.lock(); 1050 1051 // 获取物理页的anon_vma的守卫 1052 let mut page_manager_guard: SpinLockGuard<'_, crate::mm::page::PageManager> = 1053 page_manager_lock_irqsave(); 1054 for page in guard.region.pages() { 1055 if mapper.translate(page.virt_address()).is_none() { 1056 continue; 1057 } 1058 let (paddr, _, flush) = unsafe { mapper.unmap_phys(page.virt_address(), true) } 1059 .expect("Failed to unmap, beacuse of some page is not mapped"); 1060 1061 // 从anon_vma中删除当前VMA 1062 let page = page_manager_guard.get_mut(&paddr); 1063 page.remove_vma(self); 1064 1065 // 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. 1066 if page.can_deallocate() { 1067 unsafe { 1068 deallocate_page_frames( 1069 PhysPageFrame::new(paddr), 1070 PageFrameCount::new(1), 1071 &mut page_manager_guard, 1072 ) 1073 }; 1074 } 1075 1076 flusher.consume(flush); 1077 } 1078 guard.mapped = false; 1079 } 1080 1081 pub fn mapped(&self) -> bool { 1082 return self.vma.lock().mapped; 1083 } 1084 1085 /// 将当前VMA进行切分，切分成3个VMA，分别是： 1086 /// 1087 /// 1. 前面的VMA，如果没有则为None 1088 /// 2. 中间的VMA，也就是传入的Region 1089 /// 3. 后面的VMA，如果没有则为None 1090 pub fn extract(&self, region: VirtRegion, utable: &PageMapper) -> Option<VMASplitResult> { 1091 assert!(region.start().check_aligned(MMArch::PAGE_SIZE)); 1092 assert!(region.end().check_aligned(MMArch::PAGE_SIZE)); 1093 1094 let mut guard = self.lock(); 1095 { 1096 // 如果传入的region不在当前VMA的范围内，则直接返回None 1097 if unlikely(region.start() < guard.region.start() || region.end() > guard.region.end()) 1098 { 1099 return None; 1100 } 1101 1102 let intersect: Option<VirtRegion> = guard.region.intersect(®ion); 1103 // 如果当前VMA不包含region，则直接返回None 1104 if unlikely(intersect.is_none()) { 1105 return None; 1106 } 1107 let intersect: VirtRegion = intersect.unwrap(); 1108 if unlikely(intersect == guard.region) { 1109 // 如果当前VMA完全包含region，则直接返回当前VMA 1110 return Some(VMASplitResult::new( 1111 None, 1112 guard.self_ref.upgrade().unwrap(), 1113 None, 1114 )); 1115 } 1116 } 1117 1118 let before: Option<Arc<LockedVMA>> = guard.region.before(®ion).map(|virt_region| { 1119 let mut vma: VMA = unsafe { guard.clone() }; 1120 vma.region = virt_region; 1121 vma.mapped = false; 1122 let vma: Arc<LockedVMA> = LockedVMA::new(vma); 1123 vma 1124 }); 1125 1126 let after: Option<Arc<LockedVMA>> = guard.region.after(®ion).map(|virt_region| { 1127 let mut vma: VMA = unsafe { guard.clone() }; 1128 vma.region = virt_region; 1129 vma.mapped = false; 1130 let vma: Arc<LockedVMA> = LockedVMA::new(vma); 1131 vma 1132 }); 1133 1134 // 重新设置before、after这两个VMA里面的物理页的anon_vma 1135 let mut page_manager_guard = page_manager_lock_irqsave(); 1136 if let Some(before) = before.clone() { 1137 let virt_iter = before.lock().region.iter_pages(); 1138 for frame in virt_iter { 1139 if let Some((paddr, _)) = utable.translate(frame.virt_address()) { 1140 let page = page_manager_guard.get_mut(&paddr); 1141 page.insert_vma(before.clone()); 1142 page.remove_vma(self); 1143 before.lock().mapped = true; 1144 } 1145 } 1146 } 1147 1148 if let Some(after) = after.clone() { 1149 let virt_iter = after.lock().region.iter_pages(); 1150 for frame in virt_iter { 1151 if let Some((paddr, _)) = utable.translate(frame.virt_address()) { 1152 let page = page_manager_guard.get_mut(&paddr); 1153 page.insert_vma(after.clone()); 1154 page.remove_vma(self); 1155 after.lock().mapped = true; 1156 } 1157 } 1158 } 1159 1160 guard.region = region; 1161 1162 return Some(VMASplitResult::new( 1163 before, 1164 guard.self_ref.upgrade().unwrap(), 1165 after, 1166 )); 1167 } 1168 1169 /// 判断VMA是否为外部（非当前进程空间）的VMA 1170 pub fn is_foreign(&self) -> bool { 1171 let guard = self.lock(); 1172 if let Some(space) = guard.user_address_space.clone() { 1173 if let Some(space) = space.upgrade() { 1174 return AddressSpace::is_current(&space); 1175 } else { 1176 return true; 1177 } 1178 } else { 1179 return true; 1180 } 1181 } 1182 1183 /// 判断VMA是否可访问 1184 pub fn is_accessible(&self) -> bool { 1185 let guard = self.lock(); 1186 let vm_access_flags: VmFlags = VmFlags::VM_READ | VmFlags::VM_WRITE | VmFlags::VM_EXEC; 1187 guard.vm_flags().intersects(vm_access_flags) 1188 } 1189 1190 /// 判断VMA是否为匿名映射 1191 pub fn is_anonymous(&self) -> bool { 1192 //TODO: 实现匿名映射判断逻辑，目前仅支持匿名映射 1193 true 1194 } 1195 1196 /// 判断VMA是否为大页映射 1197 pub fn is_hugepage(&self) -> bool { 1198 //TODO: 实现巨页映射判断逻辑，目前不支持巨页映射 1199 false 1200 } 1201 } 1202 1203 impl Drop for LockedVMA { 1204 fn drop(&mut self) { 1205 LOCKEDVMA_ID_ALLOCATOR.free(self.id); 1206 } 1207 } 1208 1209 /// VMA切分结果 1210 pub struct VMASplitResult { 1211 pub prev: Option<Arc<LockedVMA>>, 1212 pub middle: Arc<LockedVMA>, 1213 pub after: Option<Arc<LockedVMA>>, 1214 } 1215 1216 impl VMASplitResult { 1217 pub fn new( 1218 prev: Option<Arc<LockedVMA>>, 1219 middle: Arc<LockedVMA>, 1220 post: Option<Arc<LockedVMA>>, 1221 ) -> Self { 1222 Self { 1223 prev, 1224 middle, 1225 after: post, 1226 } 1227 } 1228 } 1229 1230 /// @brief 虚拟内存区域 1231 #[derive(Debug)] 1232 pub struct VMA { 1233 /// 虚拟内存区域对应的虚拟地址范围 1234 region: VirtRegion, 1235 /// 虚拟内存区域标志 1236 vm_flags: VmFlags, 1237 /// VMA内的页帧的标志 1238 flags: PageFlags<MMArch>, 1239 /// VMA内的页帧是否已经映射到页表 1240 mapped: bool, 1241 /// VMA所属的用户地址空间 1242 user_address_space: Option<Weak<AddressSpace>>, 1243 self_ref: Weak<LockedVMA>, 1244 1245 provider: Provider, 1246 } 1247 1248 impl core::hash::Hash for VMA { 1249 fn hash<H: Hasher>(&self, state: &mut H) { 1250 self.region.hash(state); 1251 self.flags.hash(state); 1252 self.mapped.hash(state); 1253 } 1254 } 1255 1256 /// 描述不同类型的内存提供者或资源 1257 #[derive(Debug)] 1258 pub enum Provider { 1259 Allocated, // TODO:其他 1260 } 1261 1262 #[allow(dead_code)] 1263 impl VMA { 1264 pub fn new( 1265 region: VirtRegion, 1266 vm_flags: VmFlags, 1267 flags: PageFlags<MMArch>, 1268 mapped: bool, 1269 ) -> Self { 1270 VMA { 1271 region, 1272 vm_flags, 1273 flags, 1274 mapped, 1275 user_address_space: None, 1276 self_ref: Weak::default(), 1277 provider: Provider::Allocated, 1278 } 1279 } 1280 1281 pub fn region(&self) -> &VirtRegion { 1282 return &self.region; 1283 } 1284 1285 pub fn vm_flags(&self) -> &VmFlags { 1286 return &self.vm_flags; 1287 } 1288 1289 pub fn set_vm_flags(&mut self, vm_flags: VmFlags) { 1290 self.vm_flags = vm_flags; 1291 } 1292 1293 pub fn set_region_size(&mut self, new_region_size: usize) { 1294 self.region.set_size(new_region_size); 1295 } 1296 1297 pub fn set_mapped(&mut self, mapped: bool) { 1298 self.mapped = mapped; 1299 } 1300 1301 /// # 拷贝当前VMA的内容 1302 /// 1303 /// ### 安全性 1304 /// 1305 /// 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。 1306 pub unsafe fn clone(&self) -> Self { 1307 return Self { 1308 region: self.region, 1309 vm_flags: self.vm_flags, 1310 flags: self.flags, 1311 mapped: self.mapped, 1312 user_address_space: self.user_address_space.clone(), 1313 self_ref: self.self_ref.clone(), 1314 provider: Provider::Allocated, 1315 }; 1316 } 1317 1318 pub fn clone_info_only(&self) -> Self { 1319 return Self { 1320 region: self.region, 1321 vm_flags: self.vm_flags, 1322 flags: self.flags, 1323 mapped: self.mapped, 1324 user_address_space: None, 1325 self_ref: Weak::default(), 1326 provider: Provider::Allocated, 1327 }; 1328 } 1329 1330 #[inline(always)] 1331 pub fn flags(&self) -> PageFlags<MMArch> { 1332 return self.flags; 1333 } 1334 1335 pub fn pages(&self) -> VirtPageFrameIter { 1336 return VirtPageFrameIter::new( 1337 VirtPageFrame::new(self.region.start()), 1338 VirtPageFrame::new(self.region.end()), 1339 ); 1340 } 1341 1342 pub fn remap( 1343 &mut self, 1344 flags: PageFlags<MMArch>, 1345 mapper: &mut PageMapper, 1346 mut flusher: impl Flusher<MMArch>, 1347 ) -> Result<(), SystemError> { 1348 for page in self.region.pages() { 1349 // debug!("remap page {:?}", page.virt_address()); 1350 if mapper.translate(page.virt_address()).is_some() { 1351 let r = unsafe { 1352 mapper 1353 .remap(page.virt_address(), flags) 1354 .expect("Failed to remap") 1355 }; 1356 flusher.consume(r); 1357 } 1358 // debug!("consume page {:?}", page.virt_address()); 1359 // debug!("remap page {:?} done", page.virt_address()); 1360 } 1361 self.flags = flags; 1362 return Ok(()); 1363 } 1364 1365 /// 检查当前VMA是否可以拥有指定的标志位 1366 /// 1367 /// ## 参数 1368 /// 1369 /// - `prot_flags` 要检查的标志位 1370 pub fn can_have_flags(&self, prot_flags: ProtFlags) -> bool { 1371 let is_downgrade = (self.flags.has_write() || !prot_flags.contains(ProtFlags::PROT_WRITE)) 1372 && (self.flags.has_execute() || !prot_flags.contains(ProtFlags::PROT_EXEC)); 1373 1374 match self.provider { 1375 Provider::Allocated { .. } => true, 1376 1377 #[allow(unreachable_patterns)] 1378 _ => is_downgrade, 1379 } 1380 } 1381 1382 /// 把物理地址映射到虚拟地址 1383 /// 1384 /// @param phys 要映射的物理地址 1385 /// @param destination 要映射到的虚拟地址 1386 /// @param count 要映射的页帧数量 1387 /// @param flags 页面标志位 1388 /// @param mapper 页表映射器 1389 /// @param flusher 页表项刷新器 1390 /// 1391 /// @return 返回映射后的虚拟内存区域 1392 pub fn physmap( 1393 phys: PhysPageFrame, 1394 destination: VirtPageFrame, 1395 count: PageFrameCount, 1396 vm_flags: VmFlags, 1397 flags: PageFlags<MMArch>, 1398 mapper: &mut PageMapper, 1399 mut flusher: impl Flusher<MMArch>, 1400 ) -> Result<Arc<LockedVMA>, SystemError> { 1401 let mut cur_phy = phys; 1402 let mut cur_dest = destination; 1403 1404 for _ in 0..count.data() { 1405 // 将物理页帧映射到虚拟页帧 1406 let r = 1407 unsafe { mapper.map_phys(cur_dest.virt_address(), cur_phy.phys_address(), flags) } 1408 .expect("Failed to map phys, may be OOM error"); 1409 1410 // todo: 增加OOM处理 1411 1412 // 刷新TLB 1413 flusher.consume(r); 1414 1415 cur_phy = cur_phy.next(); 1416 cur_dest = cur_dest.next(); 1417 } 1418 1419 let r: Arc<LockedVMA> = LockedVMA::new(VMA { 1420 region: VirtRegion::new(destination.virt_address(), count.data() * MMArch::PAGE_SIZE), 1421 vm_flags, 1422 flags, 1423 mapped: true, 1424 user_address_space: None, 1425 self_ref: Weak::default(), 1426 provider: Provider::Allocated, 1427 }); 1428 1429 // 将VMA加入到anon_vma中 1430 let mut page_manager_guard = page_manager_lock_irqsave(); 1431 cur_phy = phys; 1432 for _ in 0..count.data() { 1433 let paddr = cur_phy.phys_address(); 1434 let page = page_manager_guard.get_mut(&paddr); 1435 page.insert_vma(r.clone()); 1436 cur_phy = cur_phy.next(); 1437 } 1438 1439 return Ok(r); 1440 } 1441 1442 /// 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 1443 /// 1444 /// @param destination 要映射到的虚拟地址 1445 /// @param count 要映射的页帧数量 1446 /// @param flags 页面标志位 1447 /// @param mapper 页表映射器 1448 /// @param flusher 页表项刷新器 1449 /// 1450 /// @return 返回映射后的虚拟内存区域 1451 pub fn zeroed( 1452 destination: VirtPageFrame, 1453 page_count: PageFrameCount, 1454 vm_flags: VmFlags, 1455 flags: PageFlags<MMArch>, 1456 mapper: &mut PageMapper, 1457 mut flusher: impl Flusher<MMArch>, 1458 ) -> Result<Arc<LockedVMA>, SystemError> { 1459 let mut cur_dest: VirtPageFrame = destination; 1460 // debug!( 1461 // "VMA::zeroed: page_count = {:?}, destination={destination:?}", 1462 // page_count 1463 // ); 1464 for _ in 0..page_count.data() { 1465 // debug!( 1466 // "VMA::zeroed: cur_dest={cur_dest:?}, vaddr = {:?}", 1467 // cur_dest.virt_address() 1468 // ); 1469 let r = unsafe { mapper.map(cur_dest.virt_address(), flags) } 1470 .expect("Failed to map zero, may be OOM error"); 1471 // todo: 增加OOM处理 1472 1473 // 稍后再刷新TLB，这里取消刷新 1474 flusher.consume(r); 1475 cur_dest = cur_dest.next(); 1476 } 1477 let r = LockedVMA::new(VMA::new( 1478 VirtRegion::new( 1479 destination.virt_address(), 1480 page_count.data() * MMArch::PAGE_SIZE, 1481 ), 1482 vm_flags, 1483 flags, 1484 true, 1485 )); 1486 drop(flusher); 1487 // debug!("VMA::zeroed: flusher dropped"); 1488 1489 // 清空这些内存并将VMA加入到anon_vma中 1490 let mut page_manager_guard = page_manager_lock_irqsave(); 1491 let virt_iter: VirtPageFrameIter = 1492 VirtPageFrameIter::new(destination, destination.add(page_count)); 1493 for frame in virt_iter { 1494 let paddr = mapper.translate(frame.virt_address()).unwrap().0; 1495 1496 // 将VMA加入到anon_vma 1497 let page = page_manager_guard.get_mut(&paddr); 1498 page.insert_vma(r.clone()); 1499 } 1500 // debug!("VMA::zeroed: done"); 1501 return Ok(r); 1502 } 1503 } 1504 1505 impl Drop for VMA { 1506 fn drop(&mut self) { 1507 // 当VMA被释放时，需要确保它已经被从页表中解除映射 1508 assert!(!self.mapped, "VMA is still mapped"); 1509 } 1510 } 1511 1512 impl PartialEq for VMA { 1513 fn eq(&self, other: &Self) -> bool { 1514 return self.region == other.region; 1515 } 1516 } 1517 1518 impl Eq for VMA {} 1519 1520 impl PartialOrd for VMA { 1521 fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> { 1522 Some(self.cmp(other)) 1523 } 1524 } 1525 1526 impl Ord for VMA { 1527 fn cmp(&self, other: &Self) -> cmp::Ordering { 1528 return self.region.cmp(&other.region); 1529 } 1530 } 1531 1532 #[derive(Debug)] 1533 pub struct UserStack { 1534 // 栈底地址 1535 stack_bottom: VirtAddr, 1536 // 当前已映射的大小 1537 mapped_size: usize, 1538 /// 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！） 1539 current_sp: VirtAddr, 1540 } 1541 1542 impl UserStack { 1543 /// 默认的用户栈底地址 1544 pub const DEFAULT_USER_STACK_BOTTOM: VirtAddr = MMArch::USER_STACK_START; 1545 /// 默认的用户栈大小为8MB 1546 pub const DEFAULT_USER_STACK_SIZE: usize = 8 * 1024 * 1024; 1547 /// 用户栈的保护页数量 1548 pub const GUARD_PAGES_NUM: usize = 4; 1549 1550 /// 创建一个用户栈 1551 pub fn new( 1552 vm: &mut InnerAddressSpace, 1553 stack_bottom: Option<VirtAddr>, 1554 stack_size: usize, 1555 ) -> Result<Self, SystemError> { 1556 let stack_bottom = stack_bottom.unwrap_or(Self::DEFAULT_USER_STACK_BOTTOM); 1557 assert!(stack_bottom.check_aligned(MMArch::PAGE_SIZE)); 1558 1559 // 分配用户栈的保护页 1560 let guard_size = Self::GUARD_PAGES_NUM * MMArch::PAGE_SIZE; 1561 let actual_stack_bottom = stack_bottom - guard_size; 1562 1563 let mut prot_flags = ProtFlags::PROT_READ | ProtFlags::PROT_WRITE; 1564 let map_flags = MapFlags::MAP_PRIVATE 1565 | MapFlags::MAP_ANONYMOUS 1566 | MapFlags::MAP_FIXED_NOREPLACE 1567 | MapFlags::MAP_GROWSDOWN; 1568 // debug!( 1569 // "map anonymous stack: {:?} {}", 1570 // actual_stack_bottom, 1571 // guard_size 1572 // ); 1573 vm.map_anonymous( 1574 actual_stack_bottom, 1575 guard_size, 1576 prot_flags, 1577 map_flags, 1578 false, 1579 false, 1580 )?; 1581 // test_buddy(); 1582 // 设置保护页只读 1583 prot_flags.remove(ProtFlags::PROT_WRITE); 1584 // debug!( 1585 // "to mprotect stack guard pages: {:?} {}", 1586 // actual_stack_bottom, 1587 // guard_size 1588 // ); 1589 vm.mprotect( 1590 VirtPageFrame::new(actual_stack_bottom), 1591 PageFrameCount::new(Self::GUARD_PAGES_NUM), 1592 prot_flags, 1593 )?; 1594 1595 // debug!( 1596 // "mprotect stack guard pages done: {:?} {}", 1597 // actual_stack_bottom, 1598 // guard_size 1599 // ); 1600 1601 let mut user_stack = UserStack { 1602 stack_bottom: actual_stack_bottom, 1603 mapped_size: guard_size, 1604 current_sp: actual_stack_bottom - guard_size, 1605 }; 1606 1607 // debug!("extend user stack: {:?} {}", stack_bottom, stack_size); 1608 // 分配用户栈 1609 user_stack.initial_extend(vm, stack_size)?; 1610 // debug!("user stack created: {:?} {}", stack_bottom, stack_size); 1611 return Ok(user_stack); 1612 } 1613 1614 fn initial_extend( 1615 &mut self, 1616 vm: &mut InnerAddressSpace, 1617 mut bytes: usize, 1618 ) -> Result<(), SystemError> { 1619 let prot_flags = ProtFlags::PROT_READ | ProtFlags::PROT_WRITE | ProtFlags::PROT_EXEC; 1620 let map_flags = MapFlags::MAP_PRIVATE | MapFlags::MAP_ANONYMOUS | MapFlags::MAP_GROWSDOWN; 1621 1622 bytes = page_align_up(bytes); 1623 self.mapped_size += bytes; 1624 1625 vm.map_anonymous( 1626 self.stack_bottom - self.mapped_size, 1627 bytes, 1628 prot_flags, 1629 map_flags, 1630 false, 1631 false, 1632 )?; 1633 1634 return Ok(()); 1635 } 1636 1637 /// 扩展用户栈 1638 /// 1639 /// ## 参数 1640 /// 1641 /// - `vm` 用户地址空间结构体 1642 /// - `bytes` 要扩展的字节数 1643 /// 1644 /// ## 返回值 1645 /// 1646 /// - **Ok(())** 扩展成功 1647 /// - **Err(SystemError)** 扩展失败 1648 #[allow(dead_code)] 1649 pub fn extend( 1650 &mut self, 1651 vm: &mut InnerAddressSpace, 1652 mut bytes: usize, 1653 ) -> Result<(), SystemError> { 1654 let prot_flags = ProtFlags::PROT_READ | ProtFlags::PROT_WRITE | ProtFlags::PROT_EXEC; 1655 let map_flags = MapFlags::MAP_PRIVATE | MapFlags::MAP_ANONYMOUS; 1656 1657 bytes = page_align_up(bytes); 1658 self.mapped_size += bytes; 1659 1660 vm.map_anonymous( 1661 self.stack_bottom - self.mapped_size, 1662 bytes, 1663 prot_flags, 1664 map_flags, 1665 false, 1666 false, 1667 )?; 1668 1669 return Ok(()); 1670 } 1671 1672 /// 获取栈顶地址 1673 /// 1674 /// 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！ 1675 pub fn sp(&self) -> VirtAddr { 1676 return self.current_sp; 1677 } 1678 1679 pub unsafe fn set_sp(&mut self, sp: VirtAddr) { 1680 self.current_sp = sp; 1681 } 1682 1683 /// 仅仅克隆用户栈的信息，不会克隆用户栈的内容/映射 1684 pub unsafe fn clone_info_only(&self) -> Self { 1685 return Self { 1686 stack_bottom: self.stack_bottom, 1687 mapped_size: self.mapped_size, 1688 current_sp: self.current_sp, 1689 }; 1690 } 1691 1692 /// 获取当前用户栈的大小（不包括保护页） 1693 pub fn stack_size(&self) -> usize { 1694 return self.mapped_size - Self::GUARD_PAGES_NUM * MMArch::PAGE_SIZE; 1695 } 1696 } 1697