1 /*
2 * Copyright (C) 2008 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #include "config.h"
27
28 #include "ExecutableAllocator.h"
29
30 #if ENABLE(ASSEMBLER)
31
32 #include <sys/mman.h>
33 #include <unistd.h>
34 #include <wtf/VMTags.h>
35
36 namespace JSC {
37
38 #if !(PLATFORM(MAC) && PLATFORM(X86_64))
39
intializePageSize()40 void ExecutableAllocator::intializePageSize()
41 {
42 ExecutableAllocator::pageSize = getpagesize();
43 }
44
systemAlloc(size_t n)45 ExecutablePool::Allocation ExecutablePool::systemAlloc(size_t n)
46 {
47 ExecutablePool::Allocation alloc = { reinterpret_cast<char*>(mmap(NULL, n, INITIAL_PROTECTION_FLAGS, MAP_PRIVATE | MAP_ANON, VM_TAG_FOR_EXECUTABLEALLOCATOR_MEMORY, 0)), n };
48 return alloc;
49 }
50
systemRelease(const ExecutablePool::Allocation & alloc)51 void ExecutablePool::systemRelease(const ExecutablePool::Allocation& alloc)
52 {
53 int result = munmap(alloc.pages, alloc.size);
54 ASSERT_UNUSED(result, !result);
55 }
56
57 #endif // !(PLATFORM(MAC) && PLATFORM(X86_64))
58
59 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
reprotectRegion(void * start,size_t size,ProtectionSeting setting)60 void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSeting setting)
61 {
62 if (!pageSize)
63 intializePageSize();
64
65 // Calculate the start of the page containing this region,
66 // and account for this extra memory within size.
67 intptr_t startPtr = reinterpret_cast<intptr_t>(start);
68 intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
69 void* pageStart = reinterpret_cast<void*>(pageStartPtr);
70 size += (startPtr - pageStartPtr);
71
72 // Round size up
73 size += (pageSize - 1);
74 size &= ~(pageSize - 1);
75
76 mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
77 }
78 #endif
79
80 }
81
82 #endif // HAVE(ASSEMBLER)
83