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) && OS(UNIX) && !OS(SYMBIAN)
31
32 #include <sys/mman.h>
33 #include <unistd.h>
34 #include <wtf/VMTags.h>
35
36 namespace JSC {
37
38 #if !(OS(DARWIN) && CPU(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 void* allocation = mmap(NULL, n, INITIAL_PROTECTION_FLAGS, MAP_PRIVATE | MAP_ANON, VM_TAG_FOR_EXECUTABLEALLOCATOR_MEMORY, 0);
48 if (allocation == MAP_FAILED)
49 CRASH();
50 ExecutablePool::Allocation alloc = { reinterpret_cast<char*>(allocation), n };
51 return alloc;
52 }
53
systemRelease(const ExecutablePool::Allocation & alloc)54 void ExecutablePool::systemRelease(const ExecutablePool::Allocation& alloc)
55 {
56 int result = munmap(alloc.pages, alloc.size);
57 ASSERT_UNUSED(result, !result);
58 }
59
60 #endif // !(OS(DARWIN) && CPU(X86_64))
61
62 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
reprotectRegion(void * start,size_t size,ProtectionSeting setting)63 void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSeting setting)
64 {
65 if (!pageSize)
66 intializePageSize();
67
68 // Calculate the start of the page containing this region,
69 // and account for this extra memory within size.
70 intptr_t startPtr = reinterpret_cast<intptr_t>(start);
71 intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
72 void* pageStart = reinterpret_cast<void*>(pageStartPtr);
73 size += (startPtr - pageStartPtr);
74
75 // Round size up
76 size += (pageSize - 1);
77 size &= ~(pageSize - 1);
78
79 mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
80 }
81 #endif
82
83 }
84
85 #endif // HAVE(ASSEMBLER)
86