1/*
2* Copyright (C) 2018 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#include "SpectreGadget.h"
28
29#include "RuntimeEnabledFeatures.h"
30#include <wtf/text/WTFString.h>
31
32namespace WebCore {
33
34inline SpectreGadget::SpectreGadget(const String& text)
35{
36 if (RuntimeEnabledFeatures::sharedFeatures().spectreGadgetsEnabled()) {
37 m_data.resize(text.length());
38 setReadLength(text.length());
39 m_data.fill(0);
40 m_dataPtr = m_data.data();
41
42 for (size_t i = 0; i < m_readLength; i++)
43 m_data[i] = text.characterAt(i);
44 } else {
45 setReadLength(0);
46 m_dataPtr = nullptr;
47 }
48}
49
50Ref<SpectreGadget> SpectreGadget::create(const String& text)
51{
52 return adoptRef(*new SpectreGadget(text));
53}
54
55void SpectreGadget::setReadLength(size_t readLength)
56{
57 m_readLength = std::min(readLength, m_data.size());
58}
59
60unsigned SpectreGadget::charCodeAt(size_t index)
61{
62 if (index < m_readLength)
63 return m_dataPtr[index];
64
65 return 0;
66}
67
68void SpectreGadget::clflushReadLength()
69{
70#if CPU(X86_64) && !OS(WINDOWS)
71 auto clflush = [] (void* ptr) {
72 char* ptrToFlush = static_cast<char*>(ptr);
73 asm volatile ("clflush %0" :: "m"(*ptrToFlush) : "memory");
74 };
75
76 clflush(&m_readLength);
77#endif
78}
79
80} // namespace WebCore
81