diff options
Diffstat (limited to 'deps/v8/src/platform-posix.cc')
-rw-r--r-- | deps/v8/src/platform-posix.cc | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/deps/v8/src/platform-posix.cc b/deps/v8/src/platform-posix.cc index 52cf02963..78fece3f1 100644 --- a/deps/v8/src/platform-posix.cc +++ b/deps/v8/src/platform-posix.cc @@ -84,6 +84,34 @@ void OS::Guard(void* address, const size_t size) { #endif // __CYGWIN__ +void* OS::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) and on macos + // 10.6 and 10.7. + raw_addr &= 0x3ffff000; + raw_addr += 0x20000000; +#endif + return reinterpret_cast<void*>(raw_addr); + } + return NULL; +} + + // ---------------------------------------------------------------------------- // Math functions |