Merge bleeding edge up to 8774 into the GC branch.

src/platform-linux.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 60 matching lines @@
 
 
 double ceiling(double x) {
   return ceil(x);
 }
 
 
 static Mutex* limit_mutex = NULL;
 
 
+static void* GetRandomMmapAddr() {
+  Isolate* isolate = Isolate::UncheckedCurrent();
+  // Note that the current isolate isn't set up in a call path via
+  // CpuFeatures::Probe. We don't care about randomization in this case because
+  // the code page is immediately freed.
+  if (isolate != NULL) {
+#ifdef V8_TARGET_ARCH_X64
+    uint64_t rnd1 = V8::RandomPrivate(isolate);
+    uint64_t rnd2 = V8::RandomPrivate(isolate);
+    uint64_t raw_addr = (rnd1 << 32) ^ rnd2;
+    // Currently available CPUs have 48 bits of virtual addressing.  Truncate
+    // the hint address to 46 bits to give the kernel a fighting chance of
+    // fulfilling our placement request.
+    raw_addr &= V8_UINT64_C(0x3ffffffff000);
+#else
+    uint32_t raw_addr = V8::RandomPrivate(isolate);
+    // The range 0x20000000 - 0x60000000 is relatively unpopulated across a
+    // variety of ASLR modes (PAE kernel, NX compat mode, etc).
+    raw_addr &= 0x3ffff000;
+    raw_addr += 0x20000000;
+#endif
+    return reinterpret_cast<void*>(raw_addr);
+  }
+  return NULL;
+}
+
+
 void OS::Setup() {
-  // Seed the random number generator.
-  // Convert the current time to a 64-bit integer first, before converting it
-  // to an unsigned. Going directly can cause an overflow and the seed to be
-  // set to all ones. The seed will be identical for different instances that
-  // call this setup code within the same millisecond.
-  uint64_t seed = static_cast<uint64_t>(TimeCurrentMillis());
+  // Seed the random number generator. We preserve microsecond resolution.
+  uint64_t seed = Ticks() ^ (getpid() << 16);
   srandom(static_cast<unsigned int>(seed));
   limit_mutex = CreateMutex();
 
 #ifdef __arm__
   // When running on ARM hardware check that the EABI used by V8 and
   // by the C code is the same.
   bool hard_float = OS::ArmUsingHardFloat();
   if (hard_float) {
 #if !USE_EABI_HARDFLOAT
     PrintF("ERROR: Binary compiled with -mfloat-abi=hard but without "
@@ skipping 262 matching lines @@
 
 
 size_t OS::AllocateAlignment() {
   return sysconf(_SC_PAGESIZE);
 }
 
 
 void* OS::Allocate(const size_t requested,
                    size_t* allocated,
                    bool is_executable) {
-  // TODO(805): Port randomization of allocated executable memory to Linux.
   const size_t msize = RoundUp(requested, AllocateAlignment());
   int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
-  void* mbase = mmap(NULL, msize, prot, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  void* addr = GetRandomMmapAddr();
+  void* mbase = mmap(addr, msize, prot, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
   if (mbase == MAP_FAILED) {
     LOG(i::Isolate::Current(),
         StringEvent("OS::Allocate", "mmap failed"));
     return NULL;
   }
   *allocated = msize;
   UpdateAllocatedSpaceLimits(mbase, msize);
   return mbase;
 }
 
 
 void OS::Free(void* address, const size_t size) {
   // TODO(1240712): munmap has a return value which is ignored here.
   int result = munmap(address, size);
   USE(result);
   ASSERT(result == 0);
 }
 
 
-#ifdef ENABLE_HEAP_PROTECTION
-
-void OS::Protect(void* address, size_t size) {
-  // TODO(1240712): mprotect has a return value which is ignored here.
-  mprotect(address, size, PROT_READ);
-}
-
-
-void OS::Unprotect(void* address, size_t size, bool is_executable) {
-  // TODO(1240712): mprotect has a return value which is ignored here.
-  int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
-  mprotect(address, size, prot);
-}
-
-#endif
-
-
 void OS::Sleep(int milliseconds) {
   unsigned int ms = static_cast<unsigned int>(milliseconds);
   usleep(1000 * ms);
 }
 
 
 void OS::Abort() {
   // Redirect to std abort to signal abnormal program termination.
   abort();
 }
@@ skipping 56 matching lines @@
 }
 
 
 PosixMemoryMappedFile::~PosixMemoryMappedFile() {
   if (memory_) munmap(memory_, size_);
   fclose(file_);
 }
 
 
 void OS::LogSharedLibraryAddresses() {
-#ifdef ENABLE_LOGGING_AND_PROFILING
   // 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;
 
   // 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));
 
@@ skipping 36 matching lines @@
       // Entry not describing executable data. Skip to end of line to setup
       // reading the next entry.
       do {
         c = getc(fp);
       } while ((c != EOF) && (c != '\n'));
       if (c == EOF) break;
     }
   }
   free(lib_name);
   fclose(fp);
-#endif
 }
 
 
 static const char kGCFakeMmap[] = "/tmp/__v8_gc__";
 
 
 void OS::SignalCodeMovingGC() {
-#ifdef ENABLE_LOGGING_AND_PROFILING
   // 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.
   int size = sysconf(_SC_PAGESIZE);
   FILE* f = fopen(kGCFakeMmap, "w+");
   void* addr = mmap(NULL, size, PROT_READ | PROT_EXEC, MAP_PRIVATE,
                     fileno(f), 0);
   ASSERT(addr != MAP_FAILED);
   munmap(addr, size);
   fclose(f);
-#endif
 }
 
 
 int OS::StackWalk(Vector<OS::StackFrame> frames) {
   // backtrace is a glibc extension.
 #ifdef __GLIBC__
   int frames_size = frames.length();
   ScopedVector<void*> addresses(frames_size);
 
   int frames_count = backtrace(addresses.start(), frames_size);
@@ skipping 50 matching lines @@
   return CommitRegion(address, size, is_executable);
 }
 
 
 bool VirtualMemory::Uncommit(void* address, size_t size) {
   return UncommitRegion(address, size);
 }
 
 
 void* VirtualMemory::ReserveRegion(size_t size) {
-  void* result = mmap(NULL,
-                     size,
-                     PROT_NONE,
-                     MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE,
-                     kMmapFd,
-                     kMmapFdOffset);
+  void* result = mmap(GetRandomMmapAddr(),
+                      size,
+                      PROT_NONE,
+                      MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE,
+                      kMmapFd,
+                      kMmapFdOffset);
 
   if (result == MAP_FAILED) return NULL;
 
   return result;
 }
 
 
 bool VirtualMemory::CommitRegion(void* base, size_t size, bool is_executable) {
   int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
   if (MAP_FAILED == mmap(base,
@@ skipping 127 matching lines @@
 class LinuxMutex : public Mutex {
  public:
   LinuxMutex() {
     pthread_mutexattr_t attrs;
     int result = pthread_mutexattr_init(&attrs);
     ASSERT(result == 0);
     result = pthread_mutexattr_settype(&attrs, PTHREAD_MUTEX_RECURSIVE);
     ASSERT(result == 0);
     result = pthread_mutex_init(&mutex_, &attrs);
     ASSERT(result == 0);
+    USE(result);
   }
 
   virtual ~LinuxMutex() { pthread_mutex_destroy(&mutex_); }
 
   virtual int Lock() {
     int result = pthread_mutex_lock(&mutex_);
     return result;
   }
 
   virtual int Unlock() {
@@ skipping 84 matching lines @@
     CHECK(result == -1 && errno == EINTR);  // Signal caused spurious wakeup.
   }
 }
 
 
 Semaphore* OS::CreateSemaphore(int count) {
   return new LinuxSemaphore(count);
 }
 
 
-#ifdef ENABLE_LOGGING_AND_PROFILING
-
 #if !defined(__GLIBC__) && (defined(__arm__) || defined(__thumb__))
 // Android runs a fairly new Linux kernel, so signal info is there,
 // but the C library doesn't have the structs defined.
 
 struct sigcontext {
   uint32_t trap_no;
   uint32_t error_code;
   uint32_t oldmask;
   uint32_t gregs[16];
   uint32_t arm_cpsr;
@@ skipping 267 matching lines @@
   SignalSender::AddActiveSampler(this);
 }
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SignalSender::RemoveActiveSampler(this);
   SetActive(false);
 }
 
-#endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal