/*

 * Copyright (C) 2008 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 "ExecutableAllocator.h"

#if ENABLE(ASSEMBLER)

#include <sys/mman.h>

#include <unistd.h>

#include <wtf/VMTags.h>

namespace JSC {

#if !(PLATFORM(MAC) && PLATFORM(X86_64))

void ExecutableAllocator::intializePageSize()

{

    ExecutableAllocator::pageSize = getpagesize();

}

ExecutablePool::Allocation ExecutablePool::systemAlloc(size_t n)

{

    void* allocation = mmap(NULL, n, INITIAL_PROTECTION_FLAGS, MAP_PRIVATE | MAP_ANON, VM_TAG_FOR_EXECUTABLEALLOCATOR_MEMORY, 0);

    if (allocation == MAP_FAILED)

        CRASH();

    ExecutablePool::Allocation alloc = { reinterpret_cast<char*>(allocation), n };

    return alloc;

}

void ExecutablePool::systemRelease(const ExecutablePool::Allocation& alloc)

{ 

    int result = munmap(alloc.pages, alloc.size);

    ASSERT_UNUSED(result, !result);

}

#endif // !(PLATFORM(MAC) && PLATFORM(X86_64))

#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)

void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSeting setting)

{

    if (!pageSize)

        intializePageSize();

    // Calculate the start of the page containing this region,

    // and account for this extra memory within size.

    intptr_t startPtr = reinterpret_cast<intptr_t>(start);

    intptr_t pageStartPtr = startPtr & ~(pageSize - 1);

    void* pageStart = reinterpret_cast<void*>(pageStartPtr);

    size += (startPtr - pageStartPtr);

    // Round size up

    size += (pageSize - 1);

    size &= ~(pageSize - 1);

    mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);

}

#endif

}

#endif // HAVE(ASSEMBLER)