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
32namespace JSC {
33
34size_t ExecutableAllocator::pageSize = 0;
35
36#if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
37
38void ExecutableAllocator::intializePageSize()
39{
40#if OS(SYMBIAN) && CPU(ARMV5_OR_LOWER)
41    // The moving memory model (as used in ARMv5 and earlier platforms)
42    // on Symbian OS limits the number of chunks for each process to 16.
43    // To mitigate this limitation increase the pagesize to allocate
44    // fewer, larger chunks. Set the page size to 256 Kb to compensate
45    // for moving memory model limitation
46    ExecutableAllocator::pageSize = 256 * 1024;
47#else
48    ExecutableAllocator::pageSize = WTF::pageSize();
49#endif
50}
51
52ExecutablePool::Allocation ExecutablePool::systemAlloc(size_t size)
53{
54    PageAllocation allocation = PageAllocation::allocate(size, OSAllocator::JSJITCodePages, EXECUTABLE_POOL_WRITABLE, true);
55    if (!allocation)
56        CRASH();
57    return allocation;
58}
59
60void ExecutablePool::systemRelease(ExecutablePool::Allocation& allocation)
61{
62    allocation.deallocate();
63}
64
65bool ExecutableAllocator::isValid() const
66{
67    return true;
68}
69
70bool ExecutableAllocator::underMemoryPressure()
71{
72    return false;
73}
74
75size_t ExecutableAllocator::committedByteCount()
76{
77    return 0;
78}
79
80#endif
81
82#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
83
84#if OS(WINDOWS) || OS(SYMBIAN)
85#error "ASSEMBLER_WX_EXCLUSIVE not yet suported on this platform."
86#endif
87
88void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting setting)
89{
90    if (!pageSize)
91        intializePageSize();
92
93    // Calculate the start of the page containing this region,
94    // and account for this extra memory within size.
95    intptr_t startPtr = reinterpret_cast<intptr_t>(start);
96    intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
97    void* pageStart = reinterpret_cast<void*>(pageStartPtr);
98    size += (startPtr - pageStartPtr);
99
100    // Round size up
101    size += (pageSize - 1);
102    size &= ~(pageSize - 1);
103
104    mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
105}
106
107#endif
108
109#if CPU(ARM_TRADITIONAL) && OS(LINUX) && COMPILER(RVCT)
110
111__asm void ExecutableAllocator::cacheFlush(void* code, size_t size)
112{
113    ARM
114    push {r7}
115    add r1, r1, r0
116    mov r7, #0xf0000
117    add r7, r7, #0x2
118    mov r2, #0x0
119    svc #0x0
120    pop {r7}
121    bx lr
122}
123
124#endif
125
126}
127
128#endif // HAVE(ASSEMBLER)
129