1 //===- Unix/Memory.cpp - Generic UNIX System Configuration ------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines some functions for various memory management utilities.
12 //===----------------------------------------------------------------------===//
15 #include "llvm/Support/DataTypes.h"
16 #include "llvm/Support/ErrorHandling.h"
17 #include "llvm/Support/Process.h"
19 #ifdef HAVE_SYS_MMAN_H
24 #include <mach/mach.h>
28 # if defined(__OpenBSD__)
29 # include <mips64/sysarch.h>
30 # elif !defined(__FreeBSD__)
31 # include <sys/cachectl.h>
36 extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
38 extern "C" void __clear_cache(void *, void*);
43 int getPosixProtectionFlags(unsigned Flags) {
45 case llvm::sys::Memory::MF_READ:
47 case llvm::sys::Memory::MF_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
65 return PROT_READ | PROT_EXEC;
70 llvm_unreachable("Illegal memory protection flag specified!");
72 // Provide a default return value as required by some compilers.
76 } // anonymous namespace
82 Memory::allocateMappedMemory(size_t NumBytes,
83 const MemoryBlock *const NearBlock,
85 std::error_code &EC) {
86 EC = std::error_code();
90 static const size_t PageSize = Process::getPageSize();
91 const size_t NumPages = (NumBytes+PageSize-1)/PageSize;
95 int MMFlags = MAP_PRIVATE |
101 ; // Ends statement above
103 int Protect = getPosixProtectionFlags(PFlags);
105 #if defined(__NetBSD__) && defined(PROT_MPROTECT)
106 Protect |= PROT_MPROTECT(PROT_READ | PROT_WRITE | PROT_EXEC);
109 // Use any near hint and the page size to set a page-aligned starting address
110 uintptr_t Start = NearBlock ? reinterpret_cast<uintptr_t>(NearBlock->base()) +
111 NearBlock->size() : 0;
112 if (Start && Start % PageSize)
113 Start += PageSize - Start % PageSize;
115 void *Addr = ::mmap(reinterpret_cast<void*>(Start), PageSize*NumPages,
116 Protect, MMFlags, fd, 0);
117 if (Addr == MAP_FAILED) {
118 if (NearBlock) //Try again without a near hint
119 return allocateMappedMemory(NumBytes, nullptr, PFlags, EC);
121 EC = std::error_code(errno, std::generic_category());
122 return MemoryBlock();
126 Result.Address = Addr;
127 Result.Size = NumPages*PageSize;
129 // Rely on protectMappedMemory to invalidate instruction cache.
130 if (PFlags & MF_EXEC) {
131 EC = Memory::protectMappedMemory (Result, PFlags);
132 if (EC != std::error_code())
133 return MemoryBlock();
140 Memory::releaseMappedMemory(MemoryBlock &M) {
141 if (M.Address == nullptr || M.Size == 0)
142 return std::error_code();
144 if (0 != ::munmap(M.Address, M.Size))
145 return std::error_code(errno, std::generic_category());
150 return 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();
160 return std::error_code(EINVAL, std::generic_category());
162 int Protect = getPosixProtectionFlags(Flags);
163 uintptr_t Start = alignAddr((uint8_t *)M.Address - PageSize + 1, PageSize);
164 uintptr_t End = alignAddr((uint8_t *)M.Address + M.Size, PageSize);
166 bool InvalidateCache = (Flags & MF_EXEC);
168 #if defined(__arm__) || defined(__aarch64__)
169 // Certain ARM implementations treat icache clear instruction as a memory read,
170 // and CPU segfaults on trying to clear cache on !PROT_READ page. Therefore we need
171 // to temporarily add PROT_READ for the sake of flushing the instruction caches.
172 if (InvalidateCache && !(Protect & PROT_READ)) {
173 int Result = ::mprotect((void *)Start, End - Start, Protect | PROT_READ);
175 return std::error_code(errno, std::generic_category());
177 Memory::InvalidateInstructionCache(M.Address, M.Size);
178 InvalidateCache = false;
182 int Result = ::mprotect((void *)Start, End - Start, Protect);
185 return std::error_code(errno, std::generic_category());
188 Memory::InvalidateInstructionCache(M.Address, M.Size);
190 return std::error_code();
193 /// InvalidateInstructionCache - Before the JIT can run a block of code
194 /// that has been emitted it must invalidate the instruction cache on some
196 void Memory::InvalidateInstructionCache(const void *Addr,
199 // icache invalidation for PPC and ARM.
200 #if defined(__APPLE__)
202 # if (defined(__POWERPC__) || defined (__ppc__) || \
203 defined(_POWER) || defined(_ARCH_PPC) || defined(__arm__) || \
205 sys_icache_invalidate(const_cast<void *>(Addr), Len);
210 # if (defined(__POWERPC__) || defined (__ppc__) || \
211 defined(_POWER) || defined(_ARCH_PPC)) && defined(__GNUC__)
212 const size_t LineSize = 32;
214 const intptr_t Mask = ~(LineSize - 1);
215 const intptr_t StartLine = ((intptr_t) Addr) & Mask;
216 const intptr_t EndLine = ((intptr_t) Addr + Len + LineSize - 1) & Mask;
218 for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
219 asm volatile("dcbf 0, %0" : : "r"(Line));
220 asm volatile("sync");
222 for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
223 asm volatile("icbi 0, %0" : : "r"(Line));
224 asm volatile("isync");
225 # elif (defined(__arm__) || defined(__aarch64__) || defined(__mips__)) && \
227 // FIXME: Can we safely always call this for __GNUC__ everywhere?
228 const char *Start = static_cast<const char *>(Addr);
229 const char *End = Start + Len;
230 __clear_cache(const_cast<char *>(Start), const_cast<char *>(End));
235 ValgrindDiscardTranslations(Addr, Len);