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* Copyright (C) 2008 Apple Inc. All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "ExecutableAllocator.h"
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#include <wtf/VMTags.h>
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#if !(PLATFORM(MAC) && PLATFORM(X86_64))
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void ExecutableAllocator::intializePageSize()
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ExecutableAllocator::pageSize = getpagesize();
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ExecutablePool::Allocation ExecutablePool::systemAlloc(size_t n)
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void* allocation = mmap(NULL, n, INITIAL_PROTECTION_FLAGS, MAP_PRIVATE | MAP_ANON, VM_TAG_FOR_EXECUTABLEALLOCATOR_MEMORY, 0);
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if (allocation == MAP_FAILED)
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ExecutablePool::Allocation alloc = { reinterpret_cast<char*>(allocation), n };
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void ExecutablePool::systemRelease(const ExecutablePool::Allocation& alloc)
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int result = munmap(alloc.pages, alloc.size);
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ASSERT_UNUSED(result, !result);
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#endif // !(PLATFORM(MAC) && PLATFORM(X86_64))
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#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
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void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSeting setting)
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// Calculate the start of the page containing this region,
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// and account for this extra memory within size.
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intptr_t startPtr = reinterpret_cast<intptr_t>(start);
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intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
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void* pageStart = reinterpret_cast<void*>(pageStartPtr);
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size += (startPtr - pageStartPtr);
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size += (pageSize - 1);
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size &= ~(pageSize - 1);
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mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
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#endif // HAVE(ASSEMBLER)