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
35extern "C" void sys_icache_invalidate(const void *Addr, size_t len);
36
37namespace {
38
39int getPosixProtectionFlags(unsigned Flags) {
40  switch (Flags) {
41  case llvm::sys::Memory::MF_READ:
42    return PROT_READ;
43  case llvm::sys::Memory::MF_WRITE:
44    return PROT_WRITE;
45  case llvm::sys::Memory::MF_READ|llvm::sys::Memory::MF_WRITE:
46    return PROT_READ | PROT_WRITE;
47  case llvm::sys::Memory::MF_READ|llvm::sys::Memory::MF_EXEC:
48    return PROT_READ | PROT_EXEC;
49  case llvm::sys::Memory::MF_READ |
50	 llvm::sys::Memory::MF_WRITE |
51	 llvm::sys::Memory::MF_EXEC:
52    return PROT_READ | PROT_WRITE | PROT_EXEC;
53  case llvm::sys::Memory::MF_EXEC:
54    return PROT_EXEC;
55  default:
56    llvm_unreachable("Illegal memory protection flag specified!");
57  }
58  // Provide a default return value as required by some compilers.
59  return PROT_NONE;
60}
61
62} // namespace
63
64namespace llvm {
65namespace sys {
66
67MemoryBlock
68Memory::allocateMappedMemory(size_t NumBytes,
69                             const MemoryBlock *const NearBlock,
70                             unsigned PFlags,
71                             error_code &EC) {
72  EC = error_code::success();
73  if (NumBytes == 0)
74    return MemoryBlock();
75
76  static const size_t PageSize = process::get_self()->page_size();
77  const size_t NumPages = (NumBytes+PageSize-1)/PageSize;
78
79  int fd = -1;
80#ifdef NEED_DEV_ZERO_FOR_MMAP
81  static int zero_fd = open("/dev/zero", O_RDWR);
82  if (zero_fd == -1) {
83    EC = error_code(errno, system_category());
84    return MemoryBlock();
85  }
86  fd = zero_fd;
87#endif
88
89  int MMFlags = MAP_PRIVATE |
90#ifdef HAVE_MMAP_ANONYMOUS
91  MAP_ANONYMOUS
92#else
93  MAP_ANON
94#endif
95  ; // Ends statement above
96
97  int Protect = getPosixProtectionFlags(PFlags);
98
99  // Use any near hint and the page size to set a page-aligned starting address
100  uintptr_t Start = NearBlock ? reinterpret_cast<uintptr_t>(NearBlock->base()) +
101                                      NearBlock->size() : 0;
102  if (Start && Start % PageSize)
103    Start += PageSize - Start % PageSize;
104
105  void *Addr = ::mmap(reinterpret_cast<void*>(Start), PageSize*NumPages,
106                      Protect, MMFlags, fd, 0);
107  if (Addr == MAP_FAILED) {
108    if (NearBlock) //Try again without a near hint
109      return allocateMappedMemory(NumBytes, 0, PFlags, EC);
110
111    EC = error_code(errno, system_category());
112    return MemoryBlock();
113  }
114
115  MemoryBlock Result;
116  Result.Address = Addr;
117  Result.Size = NumPages*PageSize;
118
119  if (PFlags & MF_EXEC)
120    Memory::InvalidateInstructionCache(Result.Address, Result.Size);
121
122  return Result;
123}
124
125error_code
126Memory::releaseMappedMemory(MemoryBlock &M) {
127  if (M.Address == 0 || M.Size == 0)
128    return error_code::success();
129
130  if (0 != ::munmap(M.Address, M.Size))
131    return error_code(errno, system_category());
132
133  M.Address = 0;
134  M.Size = 0;
135
136  return error_code::success();
137}
138
139error_code
140Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
141  if (M.Address == 0 || M.Size == 0)
142    return error_code::success();
143
144  if (!Flags)
145    return error_code(EINVAL, generic_category());
146
147  int Protect = getPosixProtectionFlags(Flags);
148
149  int Result = ::mprotect(M.Address, M.Size, Protect);
150  if (Result != 0)
151    return error_code(errno, system_category());
152
153  if (Flags & MF_EXEC)
154    Memory::InvalidateInstructionCache(M.Address, M.Size);
155
156  return error_code::success();
157}
158
159/// AllocateRWX - Allocate a slab of memory with read/write/execute
160/// permissions.  This is typically used for JIT applications where we want
161/// to emit code to the memory then jump to it.  Getting this type of memory
162/// is very OS specific.
163///
164MemoryBlock
165Memory::AllocateRWX(size_t NumBytes, const MemoryBlock* NearBlock,
166                    std::string *ErrMsg) {
167  if (NumBytes == 0) return MemoryBlock();
168
169  size_t PageSize = process::get_self()->page_size();
170  size_t NumPages = (NumBytes+PageSize-1)/PageSize;
171
172  int fd = -1;
173#ifdef NEED_DEV_ZERO_FOR_MMAP
174  static int zero_fd = open("/dev/zero", O_RDWR);
175  if (zero_fd == -1) {
176    MakeErrMsg(ErrMsg, "Can't open /dev/zero device");
177    return MemoryBlock();
178  }
179  fd = zero_fd;
180#endif
181
182  int flags = MAP_PRIVATE |
183#ifdef HAVE_MMAP_ANONYMOUS
184  MAP_ANONYMOUS
185#else
186  MAP_ANON
187#endif
188  ;
189
190  void* start = NearBlock ? (unsigned char*)NearBlock->base() +
191                            NearBlock->size() : 0;
192
193#if defined(__APPLE__) && defined(__arm__)
194  void *pa = ::mmap(start, PageSize*NumPages, PROT_READ|PROT_EXEC,
195                    flags, fd, 0);
196#else
197  void *pa = ::mmap(start, PageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
198                    flags, fd, 0);
199#endif
200  if (pa == MAP_FAILED) {
201    if (NearBlock) //Try again without a near hint
202      return AllocateRWX(NumBytes, 0);
203
204    MakeErrMsg(ErrMsg, "Can't allocate RWX Memory");
205    return MemoryBlock();
206  }
207
208#if defined(__APPLE__) && defined(__arm__)
209  kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)pa,
210                                (vm_size_t)(PageSize*NumPages), 0,
211                                VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
212  if (KERN_SUCCESS != kr) {
213    MakeErrMsg(ErrMsg, "vm_protect max RX failed");
214    return MemoryBlock();
215  }
216
217  kr = vm_protect(mach_task_self(), (vm_address_t)pa,
218                  (vm_size_t)(PageSize*NumPages), 0,
219                  VM_PROT_READ | VM_PROT_WRITE);
220  if (KERN_SUCCESS != kr) {
221    MakeErrMsg(ErrMsg, "vm_protect RW failed");
222    return MemoryBlock();
223  }
224#endif
225
226  MemoryBlock result;
227  result.Address = pa;
228  result.Size = NumPages*PageSize;
229
230  return result;
231}
232
233bool Memory::ReleaseRWX(MemoryBlock &M, std::string *ErrMsg) {
234  if (M.Address == 0 || M.Size == 0) return false;
235  if (0 != ::munmap(M.Address, M.Size))
236    return MakeErrMsg(ErrMsg, "Can't release RWX Memory");
237  return false;
238}
239
240bool Memory::setWritable (MemoryBlock &M, std::string *ErrMsg) {
241#if defined(__APPLE__) && defined(__arm__)
242  if (M.Address == 0 || M.Size == 0) return false;
243  Memory::InvalidateInstructionCache(M.Address, M.Size);
244  kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)M.Address,
245    (vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_WRITE);
246  return KERN_SUCCESS == kr;
247#else
248  return true;
249#endif
250}
251
252bool Memory::setExecutable (MemoryBlock &M, std::string *ErrMsg) {
253#if defined(__APPLE__) && defined(__arm__)
254  if (M.Address == 0 || M.Size == 0) return false;
255  Memory::InvalidateInstructionCache(M.Address, M.Size);
256  kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)M.Address,
257    (vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
258  return KERN_SUCCESS == kr;
259#else
260  return true;
261#endif
262}
263
264bool Memory::setRangeWritable(const void *Addr, size_t Size) {
265#if defined(__APPLE__) && defined(__arm__)
266  kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)Addr,
267                                (vm_size_t)Size, 0,
268                                VM_PROT_READ | VM_PROT_WRITE);
269  return KERN_SUCCESS == kr;
270#else
271  return true;
272#endif
273}
274
275bool Memory::setRangeExecutable(const void *Addr, size_t Size) {
276#if defined(__APPLE__) && defined(__arm__)
277  kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)Addr,
278                                (vm_size_t)Size, 0,
279                                VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
280  return KERN_SUCCESS == kr;
281#else
282  return true;
283#endif
284}
285
286/// InvalidateInstructionCache - Before the JIT can run a block of code
287/// that has been emitted it must invalidate the instruction cache on some
288/// platforms.
289void Memory::InvalidateInstructionCache(const void *Addr,
290                                        size_t Len) {
291
292// icache invalidation for PPC and ARM.
293#if defined(__APPLE__)
294
295#  if (defined(__POWERPC__) || defined (__ppc__) || \
296     defined(_POWER) || defined(_ARCH_PPC)) || defined(__arm__)
297  sys_icache_invalidate(const_cast<void *>(Addr), Len);
298#  endif
299
300#else
301
302#  if (defined(__POWERPC__) || defined (__ppc__) || \
303       defined(_POWER) || defined(_ARCH_PPC)) && defined(__GNUC__)
304  const size_t LineSize = 32;
305
306  const intptr_t Mask = ~(LineSize - 1);
307  const intptr_t StartLine = ((intptr_t) Addr) & Mask;
308  const intptr_t EndLine = ((intptr_t) Addr + Len + LineSize - 1) & Mask;
309
310  for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
311    asm volatile("dcbf 0, %0" : : "r"(Line));
312  asm volatile("sync");
313
314  for (intptr_t Line = StartLine; Line < EndLine; Line += LineSize)
315    asm volatile("icbi 0, %0" : : "r"(Line));
316  asm volatile("isync");
317#  elif defined(__arm__) && defined(__GNUC__)
318  // FIXME: Can we safely always call this for __GNUC__ everywhere?
319  const char *Start = static_cast<const char *>(Addr);
320  const char *End = Start + Len;
321  __clear_cache(const_cast<char *>(Start), const_cast<char *>(End));
322#  elif defined(__mips__)
323  const char *Start = static_cast<const char *>(Addr);
324  cacheflush(const_cast<char *>(Start), Len, BCACHE);
325#  endif
326
327#endif  // end apple
328
329  ValgrindDiscardTranslations(Addr, Len);
330}
331
332} // namespace sys
333} // namespace llvm
334