diff -r 000000000000 -r 6474c204b198 js/src/assembler/jit/ExecutableAllocatorPosix.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/assembler/jit/ExecutableAllocatorPosix.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,113 @@
+/*
+ * 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 "assembler/jit/ExecutableAllocator.h"
+
+#if ENABLE_ASSEMBLER && WTF_OS_UNIX && !WTF_OS_SYMBIAN
+
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "assembler/wtf/Assertions.h"
+#include "assembler/wtf/VMTags.h"
+#include "js/Utility.h"
+
+namespace JSC {
+
+size_t ExecutableAllocator::determinePageSize()
+{
+    return getpagesize();
+}
+
+ExecutablePool::Allocation ExecutableAllocator::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)
+        allocation = NULL;
+    ExecutablePool::Allocation alloc = { reinterpret_cast<char*>(allocation), n };
+    return alloc;
+}
+
+void ExecutableAllocator::systemRelease(const ExecutablePool::Allocation& alloc)
+{
+    int result = munmap(alloc.pages, alloc.size);
+    ASSERT_UNUSED(result, !result);
+}
+
+#if WTF_ENABLE_ASSEMBLER_WX_EXCLUSIVE
+void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting 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
+
+#if WTF_CPU_ARM_TRADITIONAL && WTF_OS_LINUX && WTF_COMPILER_RVCT
+__asm void ExecutableAllocator::cacheFlush(void* code, size_t size)
+{
+    ARM
+    push {r7}
+    add r1, r1, r0
+    mov r7, #0xf0000
+    add r7, r7, #0x2
+    mov r2, #0x0
+    svc #0x0
+    pop {r7}
+    bx lr
+}
+#endif
+
+void
+ExecutablePool::toggleAllCodeAsAccessible(bool accessible)
+{
+    char* begin = m_allocation.pages;
+    size_t size = m_freePtr - begin;
+
+    if (size) {
+        // N.B. Some systems, like 32bit Mac OS 10.6, implicitly add PROT_EXEC
+        // when mprotect'ing memory with any flag other than PROT_NONE. Be
+        // sure to use PROT_NONE when making inaccessible.
+        int flags = accessible ? PROT_READ | PROT_WRITE | PROT_EXEC : PROT_NONE;
+        if (mprotect(begin, size, flags))
+            MOZ_CRASH();
+    }
+}
+
+}
+
+#endif // HAVE(ASSEMBLER)