/* * Copyright (C) 2016 Apple Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. 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 with the distribution. * * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "config.h" #include "WasmMemory.h" #if ENABLE(WEBASSEMBLY) namespace JSC { namespace Wasm { Memory::Memory(PageCount initial, PageCount maximum) : m_mode(Mode::BoundsChecking) , m_size(initial.bytes()) , m_capacity(maximum ? maximum.bytes() : PageCount::max().bytes()) , m_initial(initial) , m_maximum(maximum) // FIXME: If we add signal based bounds checking then we need extra space for overflow on load. // see: https://bugs.webkit.org/show_bug.cgi?id=162693 { RELEASE_ASSERT(!maximum || maximum >= initial); // This should be guaranteed by our caller. m_mappedCapacity = m_capacity; // FIXME: It would be nice if we had a VM tag for wasm memory. https://bugs.webkit.org/show_bug.cgi?id=163600 void* result = mmap(nullptr, m_mappedCapacity, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0); if (result == MAP_FAILED) { // Try again with a different number. m_mappedCapacity = m_size; result = mmap(nullptr, m_mappedCapacity, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0); if (result == MAP_FAILED) return; } ASSERT(m_size <= m_mappedCapacity); if (mprotect(result, m_size, PROT_READ | PROT_WRITE)) { munmap(result, m_mappedCapacity); return; } m_memory = result; } } // namespace JSC } // namespace Wasm #endif // ENABLE(WEBASSEMBLY)