1 //===- Unix/Memory.cpp - Generic UNIX System Configuration ------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines some functions for various memory management utilities. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "Unix.h" 15 #include "llvm/Support/DataTypes.h" 16 #include "llvm/Support/ErrorHandling.h" 17 #include "llvm/Support/Process.h" 18 19 #ifdef HAVE_SYS_MMAN_H 20 #include <sys/mman.h> 21 #endif 22 23 #ifdef __APPLE__ 24 #include <mach/mach.h> 25 #endif 26 27 #if defined(__mips__) 28 # if defined(__OpenBSD__) 29 # include <mips64/sysarch.h> 30 # else 31 # include <sys/cachectl.h> 32 # endif 33 #endif 34 35 #ifdef __APPLE__ 36 extern "C" void sys_icache_invalidate(const void *Addr, size_t len); 37 #else 38 extern "C" void __clear_cache(void *, void*); 39 #endif 40 41 namespace { 42 43 int getPosixProtectionFlags(unsigned Flags) { 44 switch (Flags) { 45 case llvm::sys::Memory::MF_READ: 46 return PROT_READ; 47 case llvm::sys::Memory::MF_WRITE: 48 return PROT_WRITE; 49 case llvm::sys::Memory::MF_READ|llvm::sys::Memory::MF_WRITE: 50 return PROT_READ | PROT_WRITE; 51 case llvm::sys::Memory::MF_READ|llvm::sys::Memory::MF_EXEC: 52 return PROT_READ | PROT_EXEC; 53 case llvm::sys::Memory::MF_READ | llvm::sys::Memory::MF_WRITE | 54 llvm::sys::Memory::MF_EXEC: 55 return PROT_READ | PROT_WRITE | PROT_EXEC; 56 case llvm::sys::Memory::MF_EXEC: 57 #if defined(__FreeBSD__) 58 // On PowerPC, having an executable page that has no read permission 59 // can have unintended consequences. The function InvalidateInstruction- 60 // Cache uses instructions dcbf and icbi, both of which are treated by 61 // the processor as loads. If the page has no read permissions, 62 // executing these instructions will result in a segmentation fault. 63 // Somehow, this problem is not present on Linux, but it does happen 64 // on FreeBSD. 65 return PROT_READ | PROT_EXEC; 66 #else 67 return PROT_EXEC; 68 #endif 69 default: 70 llvm_unreachable("Illegal memory protection flag specified!"); 71 } 72 // Provide a default return value as required by some compilers. 73 return PROT_NONE; 74 } 75 76 } // anonymous namespace 77 78 namespace llvm { 79 namespace sys { 80 81 MemoryBlock 82 Memory::allocateMappedMemory(size_t NumBytes, 83 const MemoryBlock *const NearBlock, 84 unsigned PFlags, 85 std::error_code &EC) { 86 EC = std::error_code(); 87 if (NumBytes == 0) 88 return MemoryBlock(); 89 90 static const size_t PageSize = Process::getPageSize(); 91 const size_t NumPages = (NumBytes+PageSize-1)/PageSize; 92 93 int fd = -1; 94 #ifdef NEED_DEV_ZERO_FOR_MMAP 95 static int zero_fd = open("/dev/zero", O_RDWR); 96 if (zero_fd == -1) { 97 EC = std::error_code(errno, std::generic_category()); 98 return MemoryBlock(); 99 } 100 fd = zero_fd; 101 #endif 102 103 int MMFlags = MAP_PRIVATE | 104 #ifdef HAVE_MMAP_ANONYMOUS 105 MAP_ANONYMOUS 106 #else 107 MAP_ANON 108 #endif 109 ; // Ends statement above 110 111 int Protect = getPosixProtectionFlags(PFlags); 112 113 // Use any near hint and the page size to set a page-aligned starting address 114 uintptr_t Start = NearBlock ? reinterpret_cast<uintptr_t>(NearBlock->base()) + 115 NearBlock->size() : 0; 116 if (Start && Start % PageSize) 117 Start += PageSize - Start % PageSize; 118 119 void *Addr = ::mmap(reinterpret_cast<void*>(Start), PageSize*NumPages, 120 Protect, MMFlags, fd, 0); 121 if (Addr == MAP_FAILED) { 122 if (NearBlock) //Try again without a near hint 123 return allocateMappedMemory(NumBytes, nullptr, PFlags, EC); 124 125 EC = std::error_code(errno, std::generic_category()); 126 return MemoryBlock(); 127 } 128 129 MemoryBlock Result; 130 Result.Address = Addr; 131 Result.Size = NumPages*PageSize; 132 133 if (PFlags & MF_EXEC) 134 Memory::InvalidateInstructionCache(Result.Address, Result.Size); 135 136 return Result; 137 } 138 139 std::error_code 140 Memory::releaseMappedMemory(MemoryBlock &M) { 141 if (M.Address == nullptr || M.Size == 0) 142 return std::error_code(); 143 144 if (0 != ::munmap(M.Address, M.Size)) 145 return std::error_code(errno, std::generic_category()); 146 147 M.Address = nullptr; 148 M.Size = 0; 149 150 return std::error_code(); 151 } 152 153 std::error_code 154 Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) { 155 static const size_t PageSize = Process::getPageSize(); 156 if (M.Address == nullptr || M.Size == 0) 157 return std::error_code(); 158 159 if (!Flags) 160 return std::error_code(EINVAL, std::generic_category()); 161 162 int Protect = getPosixProtectionFlags(Flags); 163 164 int Result = ::mprotect((void*)((uintptr_t)M.Address & ~(PageSize-1)), PageSize*((M.Size+PageSize-1)/PageSize), Protect); 165 if (Result != 0) 166 return std::error_code(errno, std::generic_category()); 167 168 if (Flags & MF_EXEC) 169 Memory::InvalidateInstructionCache(M.Address, M.Size); 170 171 return std::error_code(); 172 } 173 174 /// AllocateRWX - Allocate a slab of memory with read/write/execute 175 /// permissions. This is typically used for JIT applications where we want 176 /// to emit code to the memory then jump to it. Getting this type of memory 177 /// is very OS specific. 178 /// 179 MemoryBlock 180 Memory::AllocateRWX(size_t NumBytes, const MemoryBlock* NearBlock, 181 std::string *ErrMsg) { 182 if (NumBytes == 0) return MemoryBlock(); 183 184 static const size_t PageSize = Process::getPageSize(); 185 size_t NumPages = (NumBytes+PageSize-1)/PageSize; 186 187 int fd = -1; 188 #ifdef NEED_DEV_ZERO_FOR_MMAP 189 static int zero_fd = open("/dev/zero", O_RDWR); 190 if (zero_fd == -1) { 191 MakeErrMsg(ErrMsg, "Can't open /dev/zero device"); 192 return MemoryBlock(); 193 } 194 fd = zero_fd; 195 #endif 196 197 int flags = MAP_PRIVATE | 198 #ifdef HAVE_MMAP_ANONYMOUS 199 MAP_ANONYMOUS 200 #else 201 MAP_ANON 202 #endif 203 ; 204 205 void* start = NearBlock ? (unsigned char*)NearBlock->base() + 206 NearBlock->size() : nullptr; 207 208 #if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__)) 209 void *pa = ::mmap(start, PageSize*NumPages, PROT_READ|PROT_EXEC, 210 flags, fd, 0); 211 #else 212 void *pa = ::mmap(start, PageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC, 213 flags, fd, 0); 214 #endif 215 if (pa == MAP_FAILED) { 216 if (NearBlock) //Try again without a near hint 217 return AllocateRWX(NumBytes, nullptr); 218 219 MakeErrMsg(ErrMsg, "Can't allocate RWX Memory"); 220 return MemoryBlock(); 221 } 222 223 #if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__)) 224 kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)pa, 225 (vm_size_t)(PageSize*NumPages), 0, 226 VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY); 227 if (KERN_SUCCESS != kr) { 228 MakeErrMsg(ErrMsg, "vm_protect max RX failed"); 229 return MemoryBlock(); 230 } 231 232 kr = vm_protect(mach_task_self(), (vm_address_t)pa, 233 (vm_size_t)(PageSize*NumPages), 0, 234 VM_PROT_READ | VM_PROT_WRITE); 235 if (KERN_SUCCESS != kr) { 236 MakeErrMsg(ErrMsg, "vm_protect RW failed"); 237 return MemoryBlock(); 238 } 239 #endif 240 241 MemoryBlock result; 242 result.Address = pa; 243 result.Size = NumPages*PageSize; 244 245 return result; 246 } 247 248 bool Memory::ReleaseRWX(MemoryBlock &M, std::string *ErrMsg) { 249 if (M.Address == nullptr || M.Size == 0) return false; 250 if (0 != ::munmap(M.Address, M.Size)) 251 return MakeErrMsg(ErrMsg, "Can't release RWX Memory"); 252 return false; 253 } 254 255 bool Memory::setWritable (MemoryBlock &M, std::string *ErrMsg) { 256 #if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__)) 257 if (M.Address == 0 || M.Size == 0) return false; 258 Memory::InvalidateInstructionCache(M.Address, M.Size); 259 kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)M.Address, 260 (vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_WRITE); 261 return KERN_SUCCESS == kr; 262 #else 263 return true; 264 #endif 265 } 266 267 bool Memory::setExecutable (MemoryBlock &M, std::string *ErrMsg) { 268 if (M.Address == nullptr || M.Size == 0) return false; 269 Memory::InvalidateInstructionCache(M.Address, M.Size); 270 #if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__)) 271 kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)M.Address, 272 (vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY); 273 return KERN_SUCCESS == kr; 274 #else 275 return true; 276 #endif 277 } 278 279 bool Memory::setRangeWritable(const void *Addr, size_t Size) { 280 #if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__)) 281 kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)Addr, 282 (vm_size_t)Size, 0, 283 VM_PROT_READ | VM_PROT_WRITE); 284 return KERN_SUCCESS == kr; 285 #else 286 return true; 287 #endif 288 } 289 290 bool Memory::setRangeExecutable(const void *Addr, size_t Size) { 291 #if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__)) 292 kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)Addr, 293 (vm_size_t)Size, 0, 294 VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY); 295 return KERN_SUCCESS == kr; 296 #else 297 return true; 298 #endif 299 } 300 301 /// InvalidateInstructionCache - Before the JIT can run a block of code 302 /// that has been emitted it must invalidate the instruction cache on some 303 /// platforms. 304 void Memory::InvalidateInstructionCache(const void *Addr, 305 size_t Len) { 306 307 // icache invalidation for PPC and ARM. 308 #if defined(__APPLE__) 309 310 # if (defined(__POWERPC__) || defined (__ppc__) || \ 311 defined(_POWER) || defined(_ARCH_PPC) || defined(__arm__) || \ 312 defined(__arm64__)) 313 sys_icache_invalidate(const_cast<void *>(Addr), Len); 314 # endif 315 316 #else 317 318 # if (defined(__POWERPC__) || defined (__ppc__) || \ 319 defined(_POWER) || defined(_ARCH_PPC)) && defined(__GNUC__) 320 const size_t LineSize = 32; 321 322 const intptr_t Mask = ~(LineSize - 1); 323 const intptr_t StartLine = ((intptr_t) Addr) & Mask; 324 const intptr_t EndLine = ((intptr_t) Addr + Len + LineSize - 1) & Mask; 325 326 for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize) 327 asm volatile("dcbf 0, %0" : : "r"(Line)); 328 asm volatile("sync"); 329 330 for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize) 331 asm volatile("icbi 0, %0" : : "r"(Line)); 332 asm volatile("isync"); 333 # elif (defined(__arm__) || defined(__aarch64__) || defined(__mips__)) && \ 334 defined(__GNUC__) 335 // FIXME: Can we safely always call this for __GNUC__ everywhere? 336 const char *Start = static_cast<const char *>(Addr); 337 const char *End = Start + Len; 338 __clear_cache(const_cast<char *>(Start), const_cast<char *>(End)); 339 # endif 340 341 #endif // end apple 342 343 ValgrindDiscardTranslations(Addr, Len); 344 } 345 346 } // namespace sys 347 } // namespace llvm 348
