1 pub mod barrier; 2 3 use alloc::vec::Vec; 4 use hashbrown::HashSet; 5 use x86::time::rdtsc; 6 use x86_64::registers::model_specific::EferFlags; 7 8 use crate::driver::uart::uart::c_uart_send_str; 9 use crate::include::bindings::bindings::{ 10 multiboot2_get_memory, multiboot2_iter, multiboot_mmap_entry_t, 11 }; 12 use crate::libs::align::page_align_up; 13 use crate::libs::lib_ui::screen_manager::scm_disable_put_to_window; 14 use crate::libs::printk::PrintkWriter; 15 use crate::libs::spinlock::SpinLock; 16 17 use crate::mm::allocator::page_frame::{FrameAllocator, PageFrameCount}; 18 use crate::mm::mmio_buddy::mmio_init; 19 use crate::{ 20 arch::MMArch, 21 mm::allocator::{buddy::BuddyAllocator, bump::BumpAllocator}, 22 }; 23 24 use crate::mm::kernel_mapper::KernelMapper; 25 use crate::mm::page::{PageEntry, PageFlags}; 26 use crate::mm::{MemoryManagementArch, PageTableKind, PhysAddr, PhysMemoryArea, VirtAddr}; 27 use crate::syscall::SystemError; 28 use crate::{kdebug, kinfo}; 29 30 use core::arch::asm; 31 use core::ffi::c_void; 32 use core::fmt::{Debug, Write}; 33 use core::mem::{self}; 34 35 use core::sync::atomic::{compiler_fence, AtomicBool, Ordering}; 36 37 pub type PageMapper = 38 crate::mm::page::PageMapper<crate::arch::x86_64::mm::X86_64MMArch, LockedFrameAllocator>; 39 40 /// @brief 用于存储物理内存区域的数组 41 static mut PHYS_MEMORY_AREAS: [PhysMemoryArea; 512] = [PhysMemoryArea { 42 base: PhysAddr::new(0), 43 size: 0, 44 }; 512]; 45 46 /// 初始的CR3寄存器的值，用于内存管理初始化时，创建的第一个内核页表的位置 47 static mut INITIAL_CR3_VALUE: PhysAddr = PhysAddr::new(0); 48 49 /// 内核的第一个页表在pml4中的索引 50 /// 顶级页表的[256, 512)项是内核的页表 51 static KERNEL_PML4E_NO: usize = (X86_64MMArch::PHYS_OFFSET & ((1 << 48) - 1)) >> 39; 52 53 static INNER_ALLOCATOR: SpinLock<Option<BuddyAllocator<MMArch>>> = SpinLock::new(None); 54 55 #[derive(Clone, Copy)] 56 pub struct X86_64MMBootstrapInfo { 57 kernel_code_start: usize, 58 kernel_code_end: usize, 59 kernel_data_end: usize, 60 kernel_rodata_end: usize, 61 start_brk: usize, 62 } 63 64 impl Debug for X86_64MMBootstrapInfo { 65 fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { 66 write!( 67 f, 68 "kernel_code_start: {:x}, kernel_code_end: {:x}, kernel_data_end: {:x}, kernel_rodata_end: {:x}, start_brk: {:x}", 69 self.kernel_code_start, self.kernel_code_end, self.kernel_data_end, self.kernel_rodata_end, self.start_brk) 70 } 71 } 72 73 pub static mut BOOTSTRAP_MM_INFO: Option<X86_64MMBootstrapInfo> = None; 74 75 /// @brief X86_64的内存管理架构结构体 76 #[derive(Debug, Clone, Copy, Hash)] 77 pub struct X86_64MMArch; 78 79 /// XD标志位是否被保留 80 static XD_RESERVED: AtomicBool = AtomicBool::new(false); 81 82 impl MemoryManagementArch for X86_64MMArch { 83 /// 4K页 84 const PAGE_SHIFT: usize = 12; 85 86 /// 每个页表项占8字节，总共有512个页表项 87 const PAGE_ENTRY_SHIFT: usize = 9; 88 89 /// 四级页表（PML4T、PDPT、PDT、PT） 90 const PAGE_LEVELS: usize = 4; 91 92 /// 页表项的有效位的index。在x86_64中，页表项的第[0, 47]位表示地址和flag， 93 /// 第[48, 51]位表示保留。因此，有效位的index为52。 94 /// 请注意，第63位是XD位，表示是否允许执行。 95 const ENTRY_ADDRESS_SHIFT: usize = 52; 96 97 const ENTRY_FLAG_DEFAULT_PAGE: usize = Self::ENTRY_FLAG_PRESENT; 98 99 const ENTRY_FLAG_DEFAULT_TABLE: usize = Self::ENTRY_FLAG_PRESENT; 100 101 const ENTRY_FLAG_PRESENT: usize = 1 << 0; 102 103 const ENTRY_FLAG_READONLY: usize = 0; 104 105 const ENTRY_FLAG_READWRITE: usize = 1 << 1; 106 107 const ENTRY_FLAG_USER: usize = 1 << 2; 108 109 const ENTRY_FLAG_WRITE_THROUGH: usize = 1 << 3; 110 111 const ENTRY_FLAG_CACHE_DISABLE: usize = 1 << 4; 112 113 const ENTRY_FLAG_NO_EXEC: usize = 1 << 63; 114 /// x86_64不存在EXEC标志位，只有NO_EXEC（XD）标志位 115 const ENTRY_FLAG_EXEC: usize = 0; 116 117 /// 物理地址与虚拟地址的偏移量 118 /// 0xffff_8000_0000_0000 119 const PHYS_OFFSET: usize = Self::PAGE_NEGATIVE_MASK + (Self::PAGE_ADDRESS_SIZE >> 1); 120 121 const USER_END_VADDR: VirtAddr = VirtAddr::new(0x0000_7eff_ffff_ffff); 122 const USER_BRK_START: VirtAddr = VirtAddr::new(0x700000000000); 123 const USER_STACK_START: VirtAddr = VirtAddr::new(0x6ffff0a00000); 124 125 /// @brief 获取物理内存区域 126 unsafe fn init() -> &'static [crate::mm::PhysMemoryArea] { 127 extern "C" { 128 fn _text(); 129 fn _etext(); 130 fn _edata(); 131 fn _erodata(); 132 fn _end(); 133 } 134 135 Self::init_xd_rsvd(); 136 137 let bootstrap_info = X86_64MMBootstrapInfo { 138 kernel_code_start: _text as usize, 139 kernel_code_end: _etext as usize, 140 kernel_data_end: _edata as usize, 141 kernel_rodata_end: _erodata as usize, 142 start_brk: _end as usize, 143 }; 144 unsafe { 145 BOOTSTRAP_MM_INFO = Some(bootstrap_info); 146 } 147 148 // 初始化物理内存区域(从multiboot2中获取) 149 let areas_count = 150 Self::init_memory_area_from_multiboot2().expect("init memory area failed"); 151 c_uart_send_str(0x3f8, "x86 64 init end\n\0".as_ptr()); 152 153 return &PHYS_MEMORY_AREAS[0..areas_count]; 154 } 155 156 /// @brief 刷新TLB中，关于指定虚拟地址的条目 157 unsafe fn invalidate_page(address: VirtAddr) { 158 compiler_fence(Ordering::SeqCst); 159 asm!("invlpg [{0}]", in(reg) address.data(), options(nostack, preserves_flags)); 160 compiler_fence(Ordering::SeqCst); 161 } 162 163 /// @brief 刷新TLB中，所有的条目 164 unsafe fn invalidate_all() { 165 compiler_fence(Ordering::SeqCst); 166 // 通过设置cr3寄存器，来刷新整个TLB 167 Self::set_table(PageTableKind::User, Self::table(PageTableKind::User)); 168 compiler_fence(Ordering::SeqCst); 169 } 170 171 /// @brief 获取顶级页表的物理地址 172 unsafe fn table(_table_kind: PageTableKind) -> PhysAddr { 173 let paddr: usize; 174 compiler_fence(Ordering::SeqCst); 175 asm!("mov {}, cr3", out(reg) paddr, options(nomem, nostack, preserves_flags)); 176 compiler_fence(Ordering::SeqCst); 177 return PhysAddr::new(paddr); 178 } 179 180 /// @brief 设置顶级页表的物理地址到处理器中 181 unsafe fn set_table(_table_kind: PageTableKind, table: PhysAddr) { 182 compiler_fence(Ordering::SeqCst); 183 asm!("mov cr3, {}", in(reg) table.data(), options(nostack, preserves_flags)); 184 compiler_fence(Ordering::SeqCst); 185 } 186 187 /// @brief 判断虚拟地址是否合法 188 fn virt_is_valid(virt: VirtAddr) -> bool { 189 return virt.is_canonical(); 190 } 191 192 /// 获取内存管理初始化时，创建的第一个内核页表的地址 193 fn initial_page_table() -> PhysAddr { 194 unsafe { 195 return INITIAL_CR3_VALUE; 196 } 197 } 198 199 /// @brief 创建新的顶层页表 200 /// 201 /// 该函数会创建页表并复制内核的映射到新的页表中 202 /// 203 /// @return 新的页表 204 fn setup_new_usermapper() -> Result<crate::mm::ucontext::UserMapper, SystemError> { 205 let new_umapper: crate::mm::page::PageMapper<X86_64MMArch, LockedFrameAllocator> = unsafe { 206 PageMapper::create(PageTableKind::User, LockedFrameAllocator) 207 .ok_or(SystemError::ENOMEM)? 208 }; 209 210 let current_ktable: KernelMapper = KernelMapper::lock(); 211 let copy_mapping = |pml4_entry_no| unsafe { 212 let entry: PageEntry<X86_64MMArch> = current_ktable 213 .table() 214 .entry(pml4_entry_no) 215 .unwrap_or_else(|| panic!("entry {} not found", pml4_entry_no)); 216 new_umapper.table().set_entry(pml4_entry_no, entry) 217 }; 218 219 // 复制内核的映射 220 for pml4_entry_no in KERNEL_PML4E_NO..512 { 221 copy_mapping(pml4_entry_no); 222 } 223 224 return Ok(crate::mm::ucontext::UserMapper::new(new_umapper)); 225 } 226 } 227 228 impl X86_64MMArch { 229 unsafe fn init_memory_area_from_multiboot2() -> Result<usize, SystemError> { 230 // 这个数组用来存放内存区域的信息（从C获取） 231 let mut mb2_mem_info: [multiboot_mmap_entry_t; 512] = mem::zeroed(); 232 c_uart_send_str(0x3f8, "init_memory_area_from_multiboot2 begin\n\0".as_ptr()); 233 234 let mut mb2_count: u32 = 0; 235 multiboot2_iter( 236 Some(multiboot2_get_memory), 237 &mut mb2_mem_info as *mut [multiboot_mmap_entry_t; 512] as usize as *mut c_void, 238 &mut mb2_count, 239 ); 240 c_uart_send_str(0x3f8, "init_memory_area_from_multiboot2 2\n\0".as_ptr()); 241 242 let mb2_count = mb2_count as usize; 243 let mut areas_count = 0usize; 244 let mut total_mem_size = 0usize; 245 for i in 0..mb2_count { 246 // Only use the memory area if its type is 1 (RAM) 247 if mb2_mem_info[i].type_ == 1 { 248 // Skip the memory area if its len is 0 249 if mb2_mem_info[i].len == 0 { 250 continue; 251 } 252 total_mem_size += mb2_mem_info[i].len as usize; 253 PHYS_MEMORY_AREAS[areas_count].base = PhysAddr::new(mb2_mem_info[i].addr as usize); 254 PHYS_MEMORY_AREAS[areas_count].size = mb2_mem_info[i].len as usize; 255 areas_count += 1; 256 } 257 } 258 c_uart_send_str(0x3f8, "init_memory_area_from_multiboot2 end\n\0".as_ptr()); 259 kinfo!("Total memory size: {} MB, total areas from multiboot2: {mb2_count}, valid areas: {areas_count}", total_mem_size / 1024 / 1024); 260 261 return Ok(areas_count); 262 } 263 264 fn init_xd_rsvd() { 265 // 读取ia32-EFER寄存器的值 266 let efer: EferFlags = x86_64::registers::model_specific::Efer::read(); 267 if !efer.contains(EferFlags::NO_EXECUTE_ENABLE) { 268 // NO_EXECUTE_ENABLE是false，那么就设置xd_reserved为true 269 kdebug!("NO_EXECUTE_ENABLE is false, set XD_RESERVED to true"); 270 XD_RESERVED.store(true, Ordering::Relaxed); 271 } 272 compiler_fence(Ordering::SeqCst); 273 } 274 275 /// 判断XD标志位是否被保留 276 pub fn is_xd_reserved() -> bool { 277 return XD_RESERVED.load(Ordering::Relaxed); 278 } 279 } 280 281 impl VirtAddr { 282 /// @brief 判断虚拟地址是否合法 283 #[inline(always)] 284 pub fn is_canonical(self) -> bool { 285 let x = self.data() & X86_64MMArch::PHYS_OFFSET; 286 // 如果x为0，说明虚拟地址的高位为0，是合法的用户地址 287 // 如果x为PHYS_OFFSET，说明虚拟地址的高位全为1，是合法的内核地址 288 return x == 0 || x == X86_64MMArch::PHYS_OFFSET; 289 } 290 } 291 292 /// @brief 初始化内存管理模块 293 pub fn mm_init() { 294 c_uart_send_str(0x3f8, "mm_init\n\0".as_ptr()); 295 PrintkWriter 296 .write_fmt(format_args!("mm_init() called\n")) 297 .unwrap(); 298 // printk_color!(GREEN, BLACK, "mm_init() called\n"); 299 static _CALL_ONCE: AtomicBool = AtomicBool::new(false); 300 if _CALL_ONCE 301 .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst) 302 .is_err() 303 { 304 c_uart_send_str(0x3f8, "mm_init err\n\0".as_ptr()); 305 panic!("mm_init() can only be called once"); 306 } 307 308 unsafe { X86_64MMArch::init() }; 309 kdebug!("bootstrap info: {:?}", unsafe { BOOTSTRAP_MM_INFO }); 310 kdebug!("phys[0]=virt[0x{:x}]", unsafe { 311 MMArch::phys_2_virt(PhysAddr::new(0)).unwrap().data() 312 }); 313 314 // 初始化内存管理器 315 unsafe { allocator_init() }; 316 // enable mmio 317 mmio_init(); 318 } 319 320 unsafe fn allocator_init() { 321 let virt_offset = BOOTSTRAP_MM_INFO.unwrap().start_brk; 322 let phy_offset = 323 unsafe { MMArch::virt_2_phys(VirtAddr::new(page_align_up(virt_offset))) }.unwrap(); 324 325 kdebug!("PhysArea[0..10] = {:?}", &PHYS_MEMORY_AREAS[0..10]); 326 let mut bump_allocator = 327 BumpAllocator::<X86_64MMArch>::new(&PHYS_MEMORY_AREAS, phy_offset.data()); 328 kdebug!( 329 "BumpAllocator created, offset={:?}", 330 bump_allocator.offset() 331 ); 332 333 // 暂存初始在head.S中指定的页表的地址，后面再考虑是否需要把它加到buddy的可用空间里面！ 334 // 现在不加的原因是，我担心会有安全漏洞问题：这些初始的页表，位于内核的数据段。如果归还到buddy， 335 // 可能会产生一定的安全风险（有的代码可能根据虚拟地址来进行安全校验） 336 let _old_page_table = MMArch::table(PageTableKind::Kernel); 337 338 let new_page_table: PhysAddr; 339 // 使用bump分配器，把所有的内存页都映射到页表 340 { 341 // 用bump allocator创建新的页表 342 let mut mapper: crate::mm::page::PageMapper<MMArch, &mut BumpAllocator<MMArch>> = 343 crate::mm::page::PageMapper::<MMArch, _>::create( 344 PageTableKind::Kernel, 345 &mut bump_allocator, 346 ) 347 .expect("Failed to create page mapper"); 348 new_page_table = mapper.table().phys(); 349 kdebug!("PageMapper created"); 350 351 // 取消最开始时候，在head.S中指定的映射(暂时不刷新TLB) 352 { 353 let table = mapper.table(); 354 let empty_entry = PageEntry::<MMArch>::new(0); 355 for i in 0..MMArch::PAGE_ENTRY_NUM { 356 table 357 .set_entry(i, empty_entry) 358 .expect("Failed to empty page table entry"); 359 } 360 } 361 kdebug!("Successfully emptied page table"); 362 363 for area in PHYS_MEMORY_AREAS.iter() { 364 // kdebug!("area: base={:?}, size={:#x}, end={:?}", area.base, area.size, area.base + area.size); 365 for i in 0..((area.size + MMArch::PAGE_SIZE - 1) / MMArch::PAGE_SIZE) { 366 let paddr = area.base.add(i * MMArch::PAGE_SIZE); 367 let vaddr = unsafe { MMArch::phys_2_virt(paddr) }.unwrap(); 368 let flags = kernel_page_flags::<MMArch>(vaddr); 369 370 let flusher = mapper 371 .map_phys(vaddr, paddr, flags) 372 .expect("Failed to map frame"); 373 // 暂时不刷新TLB 374 flusher.ignore(); 375 } 376 } 377 378 // 添加低地址的映射（在smp完成初始化之前，需要使用低地址的映射.初始化之后需要取消这一段映射） 379 LowAddressRemapping::remap_at_low_address(&mut mapper); 380 } 381 382 unsafe { 383 INITIAL_CR3_VALUE = new_page_table; 384 } 385 kdebug!( 386 "After mapping all physical memory, DragonOS used: {} KB", 387 bump_allocator.offset() / 1024 388 ); 389 390 // 初始化buddy_allocator 391 let buddy_allocator = unsafe { BuddyAllocator::<X86_64MMArch>::new(bump_allocator).unwrap() }; 392 393 // 设置全局的页帧分配器 394 unsafe { set_inner_allocator(buddy_allocator) }; 395 kinfo!("Successfully initialized buddy allocator"); 396 // 关闭显示输出 397 scm_disable_put_to_window(); 398 399 // make the new page table current 400 { 401 let mut binding = INNER_ALLOCATOR.lock(); 402 let mut allocator_guard = binding.as_mut().unwrap(); 403 kdebug!("To enable new page table."); 404 compiler_fence(Ordering::SeqCst); 405 let mapper = crate::mm::page::PageMapper::<MMArch, _>::new( 406 PageTableKind::Kernel, 407 new_page_table, 408 &mut allocator_guard, 409 ); 410 compiler_fence(Ordering::SeqCst); 411 mapper.make_current(); 412 compiler_fence(Ordering::SeqCst); 413 kdebug!("New page table enabled"); 414 } 415 kdebug!("Successfully enabled new page table"); 416 } 417 418 #[no_mangle] 419 pub extern "C" fn rs_test_buddy() { 420 test_buddy(); 421 } 422 pub fn test_buddy() { 423 // 申请内存然后写入数据然后free掉 424 // 总共申请200MB内存 425 const TOTAL_SIZE: usize = 200 * 1024 * 1024; 426 427 for i in 0..10 { 428 kdebug!("Test buddy, round: {i}"); 429 // 存放申请的内存块 430 let mut v: Vec<(PhysAddr, PageFrameCount)> = Vec::with_capacity(60 * 1024); 431 // 存放已经申请的内存块的地址（用于检查重复） 432 let mut addr_set: HashSet<PhysAddr> = HashSet::new(); 433 434 let mut allocated = 0usize; 435 436 let mut free_count = 0usize; 437 438 while allocated < TOTAL_SIZE { 439 let mut random_size = 0u64; 440 unsafe { x86::random::rdrand64(&mut random_size) }; 441 // 一次最多申请4M 442 random_size = random_size % (1024 * 4096); 443 if random_size == 0 { 444 continue; 445 } 446 let random_size = 447 core::cmp::min(page_align_up(random_size as usize), TOTAL_SIZE - allocated); 448 let random_size = PageFrameCount::from_bytes(random_size.next_power_of_two()).unwrap(); 449 // 获取帧 450 let (paddr, allocated_frame_count) = 451 unsafe { LockedFrameAllocator.allocate(random_size).unwrap() }; 452 assert!(allocated_frame_count.data().is_power_of_two()); 453 assert!(paddr.data() % MMArch::PAGE_SIZE == 0); 454 unsafe { 455 assert!(MMArch::phys_2_virt(paddr) 456 .as_ref() 457 .unwrap() 458 .check_aligned(allocated_frame_count.data() * MMArch::PAGE_SIZE)); 459 } 460 allocated += allocated_frame_count.data() * MMArch::PAGE_SIZE; 461 v.push((paddr, allocated_frame_count)); 462 assert!(addr_set.insert(paddr), "duplicate address: {:?}", paddr); 463 464 // 写入数据 465 let vaddr = unsafe { MMArch::phys_2_virt(paddr).unwrap() }; 466 let slice = unsafe { 467 core::slice::from_raw_parts_mut( 468 vaddr.data() as *mut u8, 469 allocated_frame_count.data() * MMArch::PAGE_SIZE, 470 ) 471 }; 472 for i in 0..slice.len() { 473 slice[i] = ((i + unsafe { rdtsc() } as usize) % 256) as u8; 474 } 475 476 // 随机释放一个内存块 477 if v.len() > 0 { 478 let mut random_index = 0u64; 479 unsafe { x86::random::rdrand64(&mut random_index) }; 480 // 70%概率释放 481 if random_index % 10 > 7 { 482 continue; 483 } 484 random_index = random_index % v.len() as u64; 485 let random_index = random_index as usize; 486 let (paddr, allocated_frame_count) = v.remove(random_index); 487 assert!(addr_set.remove(&paddr)); 488 unsafe { LockedFrameAllocator.free(paddr, allocated_frame_count) }; 489 free_count += allocated_frame_count.data() * MMArch::PAGE_SIZE; 490 } 491 } 492 493 kdebug!( 494 "Allocated {} MB memory, release: {} MB, no release: {} bytes", 495 allocated / 1024 / 1024, 496 free_count / 1024 / 1024, 497 (allocated - free_count) 498 ); 499 500 kdebug!("Now, to release buddy memory"); 501 // 释放所有的内存 502 for (paddr, allocated_frame_count) in v { 503 unsafe { LockedFrameAllocator.free(paddr, allocated_frame_count) }; 504 assert!(addr_set.remove(&paddr)); 505 free_count += allocated_frame_count.data() * MMArch::PAGE_SIZE; 506 } 507 508 kdebug!("release done!, allocated: {allocated}, free_count: {free_count}"); 509 } 510 } 511 /// 全局的页帧分配器 512 #[derive(Debug, Clone, Copy, Hash)] 513 pub struct LockedFrameAllocator; 514 515 impl FrameAllocator for LockedFrameAllocator { 516 unsafe fn allocate( 517 &mut self, 518 count: crate::mm::allocator::page_frame::PageFrameCount, 519 ) -> Option<(PhysAddr, PageFrameCount)> { 520 if let Some(ref mut allocator) = *INNER_ALLOCATOR.lock_irqsave() { 521 return allocator.allocate(count); 522 } else { 523 return None; 524 } 525 } 526 527 unsafe fn free( 528 &mut self, 529 address: crate::mm::PhysAddr, 530 count: crate::mm::allocator::page_frame::PageFrameCount, 531 ) { 532 assert!(count.data().is_power_of_two()); 533 if let Some(ref mut allocator) = *INNER_ALLOCATOR.lock_irqsave() { 534 return allocator.free(address, count); 535 } 536 } 537 538 unsafe fn usage(&self) -> crate::mm::allocator::page_frame::PageFrameUsage { 539 todo!() 540 } 541 } 542 543 /// 获取内核地址默认的页面标志 544 pub unsafe fn kernel_page_flags<A: MemoryManagementArch>(virt: VirtAddr) -> PageFlags<A> { 545 let info: X86_64MMBootstrapInfo = BOOTSTRAP_MM_INFO.clone().unwrap(); 546 547 if virt.data() >= info.kernel_code_start && virt.data() < info.kernel_code_end { 548 // Remap kernel code execute 549 return PageFlags::new().set_execute(true).set_write(true); 550 } else if virt.data() >= info.kernel_data_end && virt.data() < info.kernel_rodata_end { 551 // Remap kernel rodata read only 552 return PageFlags::new().set_execute(true); 553 } else { 554 return PageFlags::new().set_write(true).set_execute(true); 555 } 556 } 557 558 unsafe fn set_inner_allocator(allocator: BuddyAllocator<MMArch>) { 559 static FLAG: AtomicBool = AtomicBool::new(false); 560 if FLAG 561 .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst) 562 .is_err() 563 { 564 panic!("Cannot set inner allocator twice!"); 565 } 566 *INNER_ALLOCATOR.lock() = Some(allocator); 567 } 568 569 /// 低地址重映射的管理器 570 /// 571 /// 低地址重映射的管理器，在smp初始化完成之前，需要使用低地址的映射，因此需要在smp初始化完成之后，取消这一段映射 572 pub struct LowAddressRemapping; 573 574 impl LowAddressRemapping { 575 // 映射32M 576 const REMAP_SIZE: usize = 32 * 1024 * 1024; 577 578 pub unsafe fn remap_at_low_address( 579 mapper: &mut crate::mm::page::PageMapper<MMArch, &mut BumpAllocator<MMArch>>, 580 ) { 581 for i in 0..(Self::REMAP_SIZE / MMArch::PAGE_SIZE) { 582 let paddr = PhysAddr::new(i * MMArch::PAGE_SIZE); 583 let vaddr = VirtAddr::new(i * MMArch::PAGE_SIZE); 584 let flags = kernel_page_flags::<MMArch>(vaddr); 585 586 let flusher = mapper 587 .map_phys(vaddr, paddr, flags) 588 .expect("Failed to map frame"); 589 // 暂时不刷新TLB 590 flusher.ignore(); 591 } 592 } 593 594 /// 取消低地址的映射 595 pub unsafe fn unmap_at_low_address(flush: bool) { 596 let mut mapper = KernelMapper::lock(); 597 assert!(mapper.as_mut().is_some()); 598 for i in 0..(Self::REMAP_SIZE / MMArch::PAGE_SIZE) { 599 let vaddr = VirtAddr::new(i * MMArch::PAGE_SIZE); 600 let (_, _, flusher) = mapper 601 .as_mut() 602 .unwrap() 603 .unmap_phys(vaddr, true) 604 .expect("Failed to unmap frame"); 605 if flush == false { 606 flusher.ignore(); 607 } 608 } 609 } 610 } 611 #[no_mangle] 612 pub extern "C" fn rs_mm_init() { 613 mm_init(); 614 } 615