1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390
|
// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Platform-specific code for Linux goes here. For the POSIX-compatible
// parts, the implementation is in platform-posix.cc.
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/resource.h>
#include <sys/time.h>
// Ubuntu Dapper requires memory pages to be marked as
// executable. Otherwise, OS raises an exception when executing code
// in that page.
#include <errno.h>
#include <fcntl.h> // open
#include <stdarg.h>
#include <strings.h> // index
#include <sys/mman.h> // mmap & munmap
#include <sys/stat.h> // open
#include <sys/types.h> // mmap & munmap
#include <unistd.h> // sysconf
// GLibc on ARM defines mcontext_t has a typedef for 'struct sigcontext'.
// Old versions of the C library <signal.h> didn't define the type.
#if defined(__ANDROID__) && !defined(__BIONIC_HAVE_UCONTEXT_T) && \
(defined(__arm__) || defined(__aarch64__)) && \
!defined(__BIONIC_HAVE_STRUCT_SIGCONTEXT)
#include <asm/sigcontext.h> // NOLINT
#endif
#if defined(LEAK_SANITIZER)
#include <sanitizer/lsan_interface.h>
#endif
#include <cmath>
#undef MAP_TYPE
#include "src/base/macros.h"
#include "src/base/platform/platform.h"
#if V8_OS_NACL
#if !defined(MAP_NORESERVE)
// PNaCL doesn't have this, so we always grab all of the memory, which is bad.
#define MAP_NORESERVE 0
#endif
#elif defined(__FreeBSD_kernel__)
#include <sys/syscall.h>
#else
#include <sys/prctl.h>
#include <sys/syscall.h>
#endif
namespace v8 {
namespace base {
#ifdef __arm__
bool OS::ArmUsingHardFloat() {
// GCC versions 4.6 and above define __ARM_PCS or __ARM_PCS_VFP to specify
// the Floating Point ABI used (PCS stands for Procedure Call Standard).
// We use these as well as a couple of other defines to statically determine
// what FP ABI used.
// GCC versions 4.4 and below don't support hard-fp.
// GCC versions 4.5 may support hard-fp without defining __ARM_PCS or
// __ARM_PCS_VFP.
#define GCC_VERSION (__GNUC__ * 10000 \
+ __GNUC_MINOR__ * 100 \
+ __GNUC_PATCHLEVEL__)
#if GCC_VERSION >= 40600
#if defined(__ARM_PCS_VFP)
return true;
#else
return false;
#endif
#elif GCC_VERSION < 40500
return false;
#else
#if defined(__ARM_PCS_VFP)
return true;
#elif defined(__ARM_PCS) || defined(__SOFTFP__) || defined(__SOFTFP) || \
!defined(__VFP_FP__)
return false;
#else
#error "Your version of GCC does not report the FP ABI compiled for." \
"Please report it on this issue" \
"http://code.google.com/p/v8/issues/detail?id=2140"
#endif
#endif
#undef GCC_VERSION
}
#endif // def __arm__
const char* OS::LocalTimezone(double time, TimezoneCache* cache) {
#if V8_OS_NACL
// Missing support for tm_zone field.
return "";
#else
if (std::isnan(time)) return "";
time_t tv = static_cast<time_t>(std::floor(time/msPerSecond));
struct tm* t = localtime(&tv);
if (!t || !t->tm_zone) return "";
return t->tm_zone;
#endif
}
double OS::LocalTimeOffset(TimezoneCache* cache) {
#if V8_OS_NACL
// Missing support for tm_zone field.
return 0;
#else
time_t tv = time(NULL);
struct tm* t = localtime(&tv);
// tm_gmtoff includes any daylight savings offset, so subtract it.
return static_cast<double>(t->tm_gmtoff * msPerSecond -
(t->tm_isdst > 0 ? 3600 * msPerSecond : 0));
#endif
}
void* OS::Allocate(const size_t requested,
size_t* allocated,
bool is_executable) {
const size_t msize = RoundUp(requested, AllocateAlignment());
int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
void* addr = OS::GetRandomMmapAddr();
void* mbase = mmap(addr, msize, prot, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (mbase == MAP_FAILED) return NULL;
*allocated = msize;
return mbase;
}
std::vector<OS::SharedLibraryAddress> OS::GetSharedLibraryAddresses() {
std::vector<SharedLibraryAddress> result;
// This function assumes that the layout of the file is as follows:
// hex_start_addr-hex_end_addr rwxp <unused data> [binary_file_name]
// If we encounter an unexpected situation we abort scanning further entries.
FILE* fp = fopen("/proc/self/maps", "r");
if (fp == NULL) return result;
// Allocate enough room to be able to store a full file name.
const int kLibNameLen = FILENAME_MAX + 1;
char* lib_name = reinterpret_cast<char*>(malloc(kLibNameLen));
// This loop will terminate once the scanning hits an EOF.
while (true) {
uintptr_t start, end;
char attr_r, attr_w, attr_x, attr_p;
// Parse the addresses and permission bits at the beginning of the line.
if (fscanf(fp, "%" V8PRIxPTR "-%" V8PRIxPTR, &start, &end) != 2) break;
if (fscanf(fp, " %c%c%c%c", &attr_r, &attr_w, &attr_x, &attr_p) != 4) break;
int c;
if (attr_r == 'r' && attr_w != 'w' && attr_x == 'x') {
// Found a read-only executable entry. Skip characters until we reach
// the beginning of the filename or the end of the line.
do {
c = getc(fp);
} while ((c != EOF) && (c != '\n') && (c != '/') && (c != '['));
if (c == EOF) break; // EOF: Was unexpected, just exit.
// Process the filename if found.
if ((c == '/') || (c == '[')) {
// Push the '/' or '[' back into the stream to be read below.
ungetc(c, fp);
// Read to the end of the line. Exit if the read fails.
if (fgets(lib_name, kLibNameLen, fp) == NULL) break;
// Drop the newline character read by fgets. We do not need to check
// for a zero-length string because we know that we at least read the
// '/' or '[' character.
lib_name[strlen(lib_name) - 1] = '\0';
} else {
// No library name found, just record the raw address range.
snprintf(lib_name, kLibNameLen,
"%08" V8PRIxPTR "-%08" V8PRIxPTR, start, end);
}
result.push_back(SharedLibraryAddress(lib_name, start, end));
} else {
// Entry not describing executable data. Skip to end of line to set up
// reading the next entry.
do {
c = getc(fp);
} while ((c != EOF) && (c != '\n'));
if (c == EOF) break;
}
}
free(lib_name);
fclose(fp);
return result;
}
void OS::SignalCodeMovingGC() {
// Support for ll_prof.py.
//
// The Linux profiler built into the kernel logs all mmap's with
// PROT_EXEC so that analysis tools can properly attribute ticks. We
// do a mmap with a name known by ll_prof.py and immediately munmap
// it. This injects a GC marker into the stream of events generated
// by the kernel and allows us to synchronize V8 code log and the
// kernel log.
long size = sysconf(_SC_PAGESIZE); // NOLINT(runtime/int)
FILE* f = fopen(OS::GetGCFakeMMapFile(), "w+");
if (f == NULL) {
OS::PrintError("Failed to open %s\n", OS::GetGCFakeMMapFile());
OS::Abort();
}
void* addr = mmap(OS::GetRandomMmapAddr(), size,
#if V8_OS_NACL
// The Native Client port of V8 uses an interpreter,
// so code pages don't need PROT_EXEC.
PROT_READ,
#else
PROT_READ | PROT_EXEC,
#endif
MAP_PRIVATE, fileno(f), 0);
DCHECK_NE(MAP_FAILED, addr);
OS::Free(addr, size);
fclose(f);
}
// Constants used for mmap.
static const int kMmapFd = -1;
static const int kMmapFdOffset = 0;
VirtualMemory::VirtualMemory() : address_(NULL), size_(0) { }
VirtualMemory::VirtualMemory(size_t size)
: address_(ReserveRegion(size)), size_(size) { }
VirtualMemory::VirtualMemory(size_t size, size_t alignment)
: address_(NULL), size_(0) {
DCHECK((alignment % OS::AllocateAlignment()) == 0);
size_t request_size = RoundUp(size + alignment,
static_cast<intptr_t>(OS::AllocateAlignment()));
void* reservation = mmap(OS::GetRandomMmapAddr(),
request_size,
PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE,
kMmapFd,
kMmapFdOffset);
if (reservation == MAP_FAILED) return;
uint8_t* base = static_cast<uint8_t*>(reservation);
uint8_t* aligned_base = RoundUp(base, alignment);
DCHECK_LE(base, aligned_base);
// Unmap extra memory reserved before and after the desired block.
if (aligned_base != base) {
size_t prefix_size = static_cast<size_t>(aligned_base - base);
OS::Free(base, prefix_size);
request_size -= prefix_size;
}
size_t aligned_size = RoundUp(size, OS::AllocateAlignment());
DCHECK_LE(aligned_size, request_size);
if (aligned_size != request_size) {
size_t suffix_size = request_size - aligned_size;
OS::Free(aligned_base + aligned_size, suffix_size);
request_size -= suffix_size;
}
DCHECK(aligned_size == request_size);
address_ = static_cast<void*>(aligned_base);
size_ = aligned_size;
#if defined(LEAK_SANITIZER)
__lsan_register_root_region(address_, size_);
#endif
}
VirtualMemory::~VirtualMemory() {
if (IsReserved()) {
bool result = ReleaseRegion(address(), size());
DCHECK(result);
USE(result);
}
}
bool VirtualMemory::IsReserved() {
return address_ != NULL;
}
void VirtualMemory::Reset() {
address_ = NULL;
size_ = 0;
}
bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) {
return CommitRegion(address, size, is_executable);
}
bool VirtualMemory::Uncommit(void* address, size_t size) {
return UncommitRegion(address, size);
}
bool VirtualMemory::Guard(void* address) {
OS::Guard(address, OS::CommitPageSize());
return true;
}
void* VirtualMemory::ReserveRegion(size_t size) {
void* result = mmap(OS::GetRandomMmapAddr(),
size,
PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE,
kMmapFd,
kMmapFdOffset);
if (result == MAP_FAILED) return NULL;
#if defined(LEAK_SANITIZER)
__lsan_register_root_region(result, size);
#endif
return result;
}
bool VirtualMemory::CommitRegion(void* base, size_t size, bool is_executable) {
#if V8_OS_NACL
// The Native Client port of V8 uses an interpreter,
// so code pages don't need PROT_EXEC.
int prot = PROT_READ | PROT_WRITE;
#else
int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
#endif
if (MAP_FAILED == mmap(base,
size,
prot,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
kMmapFd,
kMmapFdOffset)) {
return false;
}
return true;
}
bool VirtualMemory::UncommitRegion(void* base, size_t size) {
return mmap(base,
size,
PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE | MAP_FIXED,
kMmapFd,
kMmapFdOffset) != MAP_FAILED;
}
bool VirtualMemory::ReleaseRegion(void* base, size_t size) {
#if defined(LEAK_SANITIZER)
__lsan_unregister_root_region(base, size);
#endif
return munmap(base, size) == 0;
}
bool VirtualMemory::HasLazyCommits() {
return true;
}
} } // namespace v8::base
|