1 use core::intrinsics::unlikely; 2 3 use alloc::sync::Arc; 4 use system_error::SystemError; 5 6 use crate::{ 7 arch::MMArch, 8 kerror, 9 libs::align::{check_aligned, page_align_up}, 10 mm::MemoryManagementArch, 11 syscall::Syscall, 12 }; 13 14 use super::{ 15 allocator::page_frame::{PageFrameCount, VirtPageFrame}, 16 ucontext::{AddressSpace, DEFAULT_MMAP_MIN_ADDR}, 17 verify_area, VirtAddr, VmFlags, 18 }; 19 20 bitflags! { 21 /// Memory protection flags 22 pub struct ProtFlags: u64 { 23 const PROT_NONE = 0x0; 24 const PROT_READ = 0x1; 25 const PROT_WRITE = 0x2; 26 const PROT_EXEC = 0x4; 27 } 28 29 /// Memory mapping flags 30 pub struct MapFlags: u64 { 31 const MAP_NONE = 0x0; 32 /// share changes 33 const MAP_SHARED = 0x1; 34 /// changes are private 35 const MAP_PRIVATE = 0x2; 36 /// Interpret addr exactly 37 const MAP_FIXED = 0x10; 38 /// don't use a file 39 const MAP_ANONYMOUS = 0x20; 40 // linux-6.1-rc5/include/uapi/asm-generic/mman.h#7 41 /// stack-like segment 42 const MAP_GROWSDOWN = 0x100; 43 /// ETXTBSY 44 const MAP_DENYWRITE = 0x800; 45 /// Mark it as an executable 46 const MAP_EXECUTABLE = 0x1000; 47 /// Pages are locked 48 const MAP_LOCKED = 0x2000; 49 /// don't check for reservations 50 const MAP_NORESERVE = 0x4000; 51 /// populate (prefault) pagetables 52 const MAP_POPULATE = 0x8000; 53 /// do not block on IO 54 const MAP_NONBLOCK = 0x10000; 55 /// give out an address that is best suited for process/thread stacks 56 const MAP_STACK = 0x20000; 57 /// create a huge page mapping 58 const MAP_HUGETLB = 0x40000; 59 /// perform synchronous page faults for the mapping 60 const MAP_SYNC = 0x80000; 61 /// MAP_FIXED which doesn't unmap underlying mapping 62 const MAP_FIXED_NOREPLACE = 0x100000; 63 64 /// For anonymous mmap, memory could be uninitialized 65 const MAP_UNINITIALIZED = 0x4000000; 66 } 67 68 /// Memory mremapping flags 69 pub struct MremapFlags: u8 { 70 const MREMAP_MAYMOVE = 1; 71 const MREMAP_FIXED = 2; 72 const MREMAP_DONTUNMAP = 4; 73 } 74 } 75 76 impl From<MapFlags> for VmFlags { 77 fn from(map_flags: MapFlags) -> Self { 78 let mut vm_flags = VmFlags::VM_NONE; 79 80 if map_flags.contains(MapFlags::MAP_GROWSDOWN) { 81 vm_flags |= VmFlags::VM_GROWSDOWN; 82 } 83 84 if map_flags.contains(MapFlags::MAP_LOCKED) { 85 vm_flags |= VmFlags::VM_LOCKED; 86 } 87 88 if map_flags.contains(MapFlags::MAP_SYNC) { 89 vm_flags |= VmFlags::VM_SYNC; 90 } 91 92 vm_flags 93 } 94 } 95 96 impl From<ProtFlags> for VmFlags { 97 fn from(prot_flags: ProtFlags) -> Self { 98 let mut vm_flags = VmFlags::VM_NONE; 99 100 if prot_flags.contains(ProtFlags::PROT_READ) { 101 vm_flags |= VmFlags::VM_READ; 102 } 103 104 if prot_flags.contains(ProtFlags::PROT_WRITE) { 105 vm_flags |= VmFlags::VM_WRITE; 106 } 107 108 if prot_flags.contains(ProtFlags::PROT_EXEC) { 109 vm_flags |= VmFlags::VM_EXEC; 110 } 111 112 vm_flags 113 } 114 } 115 116 impl Into<MapFlags> for VmFlags { 117 fn into(self) -> MapFlags { 118 let mut map_flags = MapFlags::MAP_NONE; 119 120 if self.contains(VmFlags::VM_GROWSDOWN) { 121 map_flags |= MapFlags::MAP_GROWSDOWN; 122 } 123 124 if self.contains(VmFlags::VM_LOCKED) { 125 map_flags |= MapFlags::MAP_LOCKED; 126 } 127 128 if self.contains(VmFlags::VM_SYNC) { 129 map_flags |= MapFlags::MAP_SYNC; 130 } 131 132 map_flags 133 } 134 } 135 136 impl Into<ProtFlags> for VmFlags { 137 fn into(self) -> ProtFlags { 138 let mut prot_flags = ProtFlags::PROT_NONE; 139 140 if self.contains(VmFlags::VM_READ) { 141 prot_flags |= ProtFlags::PROT_READ; 142 } 143 144 if self.contains(VmFlags::VM_WRITE) { 145 prot_flags |= ProtFlags::PROT_WRITE; 146 } 147 148 if self.contains(VmFlags::VM_EXEC) { 149 prot_flags |= ProtFlags::PROT_EXEC; 150 } 151 152 prot_flags 153 } 154 } 155 156 impl Syscall { 157 pub fn brk(new_addr: VirtAddr) -> Result<VirtAddr, SystemError> { 158 // kdebug!("brk: new_addr={:?}", new_addr); 159 let address_space = AddressSpace::current()?; 160 let mut address_space = address_space.write(); 161 162 if new_addr < address_space.brk_start || new_addr >= MMArch::USER_END_VADDR { 163 return Ok(address_space.brk); 164 } 165 if new_addr == address_space.brk { 166 return Ok(address_space.brk); 167 } 168 169 unsafe { 170 address_space 171 .set_brk(VirtAddr::new(page_align_up(new_addr.data()))) 172 .ok(); 173 174 return Ok(address_space.sbrk(0).unwrap()); 175 } 176 } 177 178 pub fn sbrk(incr: isize) -> Result<VirtAddr, SystemError> { 179 let address_space = AddressSpace::current()?; 180 assert!(address_space.read().user_mapper.utable.is_current()); 181 let mut address_space = address_space.write(); 182 let r = unsafe { address_space.sbrk(incr) }; 183 184 return r; 185 } 186 187 /// ## mmap系统调用 188 /// 189 /// 该函数的实现参考了Linux内核的实现，但是并不完全相同。因为有些功能咱们还没实现 190 /// 191 /// ## 参数 192 /// 193 /// - `start_vaddr`：映射的起始地址 194 /// - `len`：映射的长度 195 /// - `prot`：保护标志 196 /// - `flags`：映射标志 197 /// - `fd`：文件描述符（暂时不支持） 198 /// - `offset`：文件偏移量 （暂时不支持） 199 /// 200 /// ## 返回值 201 /// 202 /// 成功时返回映射的起始地址，失败时返回错误码 203 pub fn mmap( 204 start_vaddr: VirtAddr, 205 len: usize, 206 prot_flags: usize, 207 map_flags: usize, 208 _fd: i32, 209 _offset: usize, 210 ) -> Result<usize, SystemError> { 211 let map_flags = MapFlags::from_bits_truncate(map_flags as u64); 212 let prot_flags = ProtFlags::from_bits_truncate(prot_flags as u64); 213 214 if start_vaddr < VirtAddr::new(DEFAULT_MMAP_MIN_ADDR) 215 && map_flags.contains(MapFlags::MAP_FIXED) 216 { 217 kerror!( 218 "mmap: MAP_FIXED is not supported for address below {}", 219 DEFAULT_MMAP_MIN_ADDR 220 ); 221 return Err(SystemError::EINVAL); 222 } 223 // 暂时不支持除匿名页以外的映射 224 if !map_flags.contains(MapFlags::MAP_ANONYMOUS) { 225 kerror!("mmap: not support file mapping"); 226 return Err(SystemError::EOPNOTSUPP_OR_ENOTSUP); 227 } 228 229 // 暂时不支持巨页映射 230 if map_flags.contains(MapFlags::MAP_HUGETLB) { 231 kerror!("mmap: not support huge page mapping"); 232 return Err(SystemError::EOPNOTSUPP_OR_ENOTSUP); 233 } 234 let current_address_space = AddressSpace::current()?; 235 let start_page = current_address_space.write().map_anonymous( 236 start_vaddr, 237 len, 238 prot_flags, 239 map_flags, 240 true, 241 )?; 242 return Ok(start_page.virt_address().data()); 243 } 244 245 /// ## mremap系统调用 246 /// 247 /// 248 /// ## 参数 249 /// 250 /// - `old_vaddr`：原映射的起始地址 251 /// - `old_len`：原映射的长度 252 /// - `new_len`：重新映射的长度 253 /// - `mremap_flags`：重映射标志 254 /// - `new_vaddr`：重新映射的起始地址 255 /// 256 /// ## 返回值 257 /// 258 /// 成功时返回重映射的起始地址，失败时返回错误码 259 pub fn mremap( 260 old_vaddr: VirtAddr, 261 old_len: usize, 262 new_len: usize, 263 mremap_flags: MremapFlags, 264 new_vaddr: VirtAddr, 265 ) -> Result<usize, SystemError> { 266 // 需要重映射到新内存区域的情况下，必须包含MREMAP_MAYMOVE并且指定新地址 267 if mremap_flags.contains(MremapFlags::MREMAP_FIXED) 268 && (!mremap_flags.contains(MremapFlags::MREMAP_MAYMOVE) 269 || new_vaddr == VirtAddr::new(0)) 270 { 271 return Err(SystemError::EINVAL); 272 } 273 274 // 不取消旧映射的情况下，必须包含MREMAP_MAYMOVE并且新内存大小等于旧内存大小 275 if mremap_flags.contains(MremapFlags::MREMAP_DONTUNMAP) 276 && (!mremap_flags.contains(MremapFlags::MREMAP_MAYMOVE) || old_len != new_len) 277 { 278 return Err(SystemError::EINVAL); 279 } 280 281 // 旧内存地址必须对齐 282 if !old_vaddr.check_aligned(MMArch::PAGE_SIZE) { 283 return Err(SystemError::EINVAL); 284 } 285 286 // 将old_len、new_len 对齐页面大小 287 let old_len = page_align_up(old_len); 288 let new_len = page_align_up(new_len); 289 290 // 不允许重映射内存区域大小为0 291 if new_len == 0 { 292 return Err(SystemError::EINVAL); 293 } 294 295 let current_address_space = AddressSpace::current()?; 296 let vma = current_address_space.read().mappings.contains(old_vaddr); 297 if vma.is_none() { 298 return Err(SystemError::EINVAL); 299 } 300 let vma = vma.unwrap(); 301 let vm_flags = vma.lock().vm_flags().clone(); 302 303 // 暂时不支持巨页映射 304 if vm_flags.contains(VmFlags::VM_HUGETLB) { 305 kerror!("mmap: not support huge page mapping"); 306 return Err(SystemError::ENOSYS); 307 } 308 309 // 缩小旧内存映射区域 310 if old_len > new_len { 311 Self::munmap(old_vaddr + new_len, old_len - new_len)?; 312 return Ok(old_vaddr.data()); 313 } 314 315 // 重映射到新内存区域 316 let r = current_address_space.write().mremap( 317 old_vaddr, 318 old_len, 319 new_len, 320 mremap_flags, 321 new_vaddr, 322 vm_flags, 323 )?; 324 325 if !mremap_flags.contains(MremapFlags::MREMAP_DONTUNMAP) { 326 Self::munmap(old_vaddr, old_len)?; 327 } 328 329 return Ok(r.data()); 330 } 331 332 /// ## munmap系统调用 333 /// 334 /// ## 参数 335 /// 336 /// - `start_vaddr`：取消映射的起始地址（已经对齐到页） 337 /// - `len`：取消映射的字节数(已经对齐到页) 338 /// 339 /// ## 返回值 340 /// 341 /// 成功时返回0，失败时返回错误码 342 pub fn munmap(start_vaddr: VirtAddr, len: usize) -> Result<usize, SystemError> { 343 assert!(start_vaddr.check_aligned(MMArch::PAGE_SIZE)); 344 assert!(check_aligned(len, MMArch::PAGE_SIZE)); 345 346 if unlikely(verify_area(start_vaddr, len).is_err()) { 347 return Err(SystemError::EINVAL); 348 } 349 if unlikely(len == 0) { 350 return Err(SystemError::EINVAL); 351 } 352 353 let current_address_space: Arc<AddressSpace> = AddressSpace::current()?; 354 let start_frame = VirtPageFrame::new(start_vaddr); 355 let page_count = PageFrameCount::new(len / MMArch::PAGE_SIZE); 356 357 current_address_space 358 .write() 359 .munmap(start_frame, page_count) 360 .map_err(|_| SystemError::EINVAL)?; 361 362 return Ok(0); 363 } 364 365 /// ## mprotect系统调用 366 /// 367 /// ## 参数 368 /// 369 /// - `start_vaddr`：起始地址(已经对齐到页) 370 /// - `len`：长度(已经对齐到页) 371 /// - `prot_flags`：保护标志 372 pub fn mprotect( 373 start_vaddr: VirtAddr, 374 len: usize, 375 prot_flags: usize, 376 ) -> Result<usize, SystemError> { 377 assert!(start_vaddr.check_aligned(MMArch::PAGE_SIZE)); 378 assert!(check_aligned(len, MMArch::PAGE_SIZE)); 379 380 if unlikely(verify_area(start_vaddr, len).is_err()) { 381 return Err(SystemError::EINVAL); 382 } 383 if unlikely(len == 0) { 384 return Err(SystemError::EINVAL); 385 } 386 387 let prot_flags = ProtFlags::from_bits(prot_flags as u64).ok_or(SystemError::EINVAL)?; 388 389 let current_address_space: Arc<AddressSpace> = AddressSpace::current()?; 390 let start_frame = VirtPageFrame::new(start_vaddr); 391 let page_count = PageFrameCount::new(len / MMArch::PAGE_SIZE); 392 393 current_address_space 394 .write() 395 .mprotect(start_frame, page_count, prot_flags) 396 .map_err(|_| SystemError::EINVAL)?; 397 return Ok(0); 398 } 399 } 400