Line data Source code
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/Config/config.h"
16 : #include "llvm/Support/DataTypes.h"
17 : #include "llvm/Support/ErrorHandling.h"
18 : #include "llvm/Support/Process.h"
19 :
20 : #ifdef HAVE_SYS_MMAN_H
21 : #include <sys/mman.h>
22 : #endif
23 :
24 : #ifdef __APPLE__
25 : #include <mach/mach.h>
26 : #endif
27 :
28 : #ifdef __Fuchsia__
29 : #include <zircon/syscalls.h>
30 : #endif
31 :
32 : #if defined(__mips__)
33 : # if defined(__OpenBSD__)
34 : # include <mips64/sysarch.h>
35 : # elif !defined(__FreeBSD__)
36 : # include <sys/cachectl.h>
37 : # endif
38 : #endif
39 :
40 : #if defined(__APPLE__)
41 : extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
42 : #else
43 : extern "C" void __clear_cache(void *, void*);
44 : #endif
45 :
46 : namespace {
47 :
48 : int getPosixProtectionFlags(unsigned Flags) {
49 932 : switch (Flags) {
50 : case llvm::sys::Memory::MF_READ:
51 : return PROT_READ;
52 22 : case llvm::sys::Memory::MF_WRITE:
53 : return PROT_WRITE;
54 1462 : case llvm::sys::Memory::MF_READ|llvm::sys::Memory::MF_WRITE:
55 : return PROT_READ | PROT_WRITE;
56 853 : case llvm::sys::Memory::MF_READ|llvm::sys::Memory::MF_EXEC:
57 : return PROT_READ | PROT_EXEC;
58 66 : case llvm::sys::Memory::MF_READ | llvm::sys::Memory::MF_WRITE |
59 : llvm::sys::Memory::MF_EXEC:
60 : return PROT_READ | PROT_WRITE | PROT_EXEC;
61 44 : case llvm::sys::Memory::MF_EXEC:
62 : #if defined(__FreeBSD__)
63 : // On PowerPC, having an executable page that has no read permission
64 : // can have unintended consequences. The function InvalidateInstruction-
65 : // Cache uses instructions dcbf and icbi, both of which are treated by
66 : // the processor as loads. If the page has no read permissions,
67 : // executing these instructions will result in a segmentation fault.
68 : // Somehow, this problem is not present on Linux, but it does happen
69 : // on FreeBSD.
70 : return PROT_READ | PROT_EXEC;
71 : #else
72 : return PROT_EXEC;
73 : #endif
74 0 : default:
75 0 : llvm_unreachable("Illegal memory protection flag specified!");
76 : }
77 : // Provide a default return value as required by some compilers.
78 : return PROT_NONE;
79 : }
80 :
81 : } // anonymous namespace
82 :
83 : namespace llvm {
84 : namespace sys {
85 :
86 : MemoryBlock
87 1551 : Memory::allocateMappedMemory(size_t NumBytes,
88 : const MemoryBlock *const NearBlock,
89 : unsigned PFlags,
90 : std::error_code &EC) {
91 1551 : EC = std::error_code();
92 1551 : if (NumBytes == 0)
93 0 : return MemoryBlock();
94 :
95 1551 : static const size_t PageSize = Process::getPageSize();
96 1551 : const size_t NumPages = (NumBytes+PageSize-1)/PageSize;
97 :
98 : int fd = -1;
99 :
100 : int MMFlags = MAP_PRIVATE |
101 : #ifdef MAP_ANONYMOUS
102 : MAP_ANONYMOUS
103 : #else
104 : MAP_ANON
105 : #endif
106 : ; // Ends statement above
107 :
108 : int Protect = getPosixProtectionFlags(PFlags);
109 :
110 : #if defined(__NetBSD__) && defined(PROT_MPROTECT)
111 : Protect |= PROT_MPROTECT(PROT_READ | PROT_WRITE | PROT_EXEC);
112 : #endif
113 :
114 : // Use any near hint and the page size to set a page-aligned starting address
115 1551 : uintptr_t Start = NearBlock ? reinterpret_cast<uintptr_t>(NearBlock->base()) +
116 814 : NearBlock->size() : 0;
117 814 : if (Start && Start % PageSize)
118 24 : Start += PageSize - Start % PageSize;
119 :
120 1551 : void *Addr = ::mmap(reinterpret_cast<void*>(Start), PageSize*NumPages,
121 : Protect, MMFlags, fd, 0);
122 1551 : if (Addr == MAP_FAILED) {
123 0 : if (NearBlock) //Try again without a near hint
124 0 : return allocateMappedMemory(NumBytes, nullptr, PFlags, EC);
125 :
126 0 : EC = std::error_code(errno, std::generic_category());
127 0 : return MemoryBlock();
128 : }
129 :
130 : MemoryBlock Result;
131 1551 : Result.Address = Addr;
132 1551 : Result.Size = NumPages*PageSize;
133 :
134 : // Rely on protectMappedMemory to invalidate instruction cache.
135 1551 : if (PFlags & MF_EXEC) {
136 71 : EC = Memory::protectMappedMemory (Result, PFlags);
137 : if (EC != std::error_code())
138 0 : return MemoryBlock();
139 : }
140 :
141 1551 : return Result;
142 : }
143 :
144 : std::error_code
145 1143 : Memory::releaseMappedMemory(MemoryBlock &M) {
146 1143 : if (M.Address == nullptr || M.Size == 0)
147 120 : return std::error_code();
148 :
149 1023 : if (0 != ::munmap(M.Address, M.Size))
150 0 : return std::error_code(errno, std::generic_category());
151 :
152 1023 : M.Address = nullptr;
153 1023 : M.Size = 0;
154 :
155 1023 : return std::error_code();
156 : }
157 :
158 : std::error_code
159 932 : Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
160 932 : static const size_t PageSize = Process::getPageSize();
161 932 : if (M.Address == nullptr || M.Size == 0)
162 0 : return std::error_code();
163 :
164 932 : if (!Flags)
165 0 : return std::error_code(EINVAL, std::generic_category());
166 :
167 : int Protect = getPosixProtectionFlags(Flags);
168 932 : uintptr_t Start = alignAddr((uint8_t *)M.Address - PageSize + 1, PageSize);
169 932 : uintptr_t End = alignAddr((uint8_t *)M.Address + M.Size, PageSize);
170 :
171 932 : bool InvalidateCache = (Flags & MF_EXEC);
172 :
173 : #if defined(__arm__) || defined(__aarch64__)
174 : // Certain ARM implementations treat icache clear instruction as a memory read,
175 : // and CPU segfaults on trying to clear cache on !PROT_READ page. Therefore we need
176 : // to temporarily add PROT_READ for the sake of flushing the instruction caches.
177 : if (InvalidateCache && !(Protect & PROT_READ)) {
178 : int Result = ::mprotect((void *)Start, End - Start, Protect | PROT_READ);
179 : if (Result != 0)
180 : return std::error_code(errno, std::generic_category());
181 :
182 : Memory::InvalidateInstructionCache(M.Address, M.Size);
183 : InvalidateCache = false;
184 : }
185 : #endif
186 :
187 932 : int Result = ::mprotect((void *)Start, End - Start, Protect);
188 :
189 932 : if (Result != 0)
190 0 : return std::error_code(errno, std::generic_category());
191 :
192 932 : if (InvalidateCache)
193 892 : Memory::InvalidateInstructionCache(M.Address, M.Size);
194 :
195 932 : return std::error_code();
196 : }
197 :
198 : /// InvalidateInstructionCache - Before the JIT can run a block of code
199 : /// that has been emitted it must invalidate the instruction cache on some
200 : /// platforms.
201 892 : void Memory::InvalidateInstructionCache(const void *Addr,
202 : size_t Len) {
203 :
204 : // icache invalidation for PPC and ARM.
205 : #if defined(__APPLE__)
206 :
207 : # if (defined(__POWERPC__) || defined (__ppc__) || \
208 : defined(_POWER) || defined(_ARCH_PPC) || defined(__arm__) || \
209 : defined(__arm64__))
210 : sys_icache_invalidate(const_cast<void *>(Addr), Len);
211 : # endif
212 :
213 : #elif defined(__Fuchsia__)
214 :
215 : zx_status_t Status = zx_cache_flush(Addr, Len, ZX_CACHE_FLUSH_INSN);
216 : assert(Status == ZX_OK && "cannot invalidate instruction cache");
217 :
218 : #else
219 :
220 : # if (defined(__POWERPC__) || defined (__ppc__) || \
221 : defined(_POWER) || defined(_ARCH_PPC)) && defined(__GNUC__)
222 : const size_t LineSize = 32;
223 :
224 : const intptr_t Mask = ~(LineSize - 1);
225 : const intptr_t StartLine = ((intptr_t) Addr) & Mask;
226 : const intptr_t EndLine = ((intptr_t) Addr + Len + LineSize - 1) & Mask;
227 :
228 : for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
229 : asm volatile("dcbf 0, %0" : : "r"(Line));
230 : asm volatile("sync");
231 :
232 : for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
233 : asm volatile("icbi 0, %0" : : "r"(Line));
234 : asm volatile("isync");
235 : # elif (defined(__arm__) || defined(__aarch64__) || defined(__mips__)) && \
236 : defined(__GNUC__)
237 : // FIXME: Can we safely always call this for __GNUC__ everywhere?
238 : const char *Start = static_cast<const char *>(Addr);
239 : const char *End = Start + Len;
240 : __builtin___clear_cache(const_cast<char *>(Start), const_cast<char *>(End));
241 : # endif
242 :
243 : #endif // end apple
244 :
245 892 : ValgrindDiscardTranslations(Addr, Len);
246 892 : }
247 :
248 : } // namespace sys
249 : } // namespace llvm
|
