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/*
* Copyright (C) 2008-2021 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.
*/
#pragma once
#if ENABLE(ASSEMBLER)
#include "ExecutableAllocator.h"
#include "JITCompilationEffort.h"
#include "SecureARM64EHashPinsInlines.h"
#include "stdint.h"
#include <string.h>
#include <wtf/Assertions.h>
#include <wtf/FastMalloc.h>
#if CPU(ARM64E)
#include <wtf/PtrTag.h>
#endif
#include <wtf/StdLibExtras.h>
#include <wtf/ThreadSpecific.h>
#include <wtf/UnalignedAccess.h>
namespace JSC {
class AssemblerData;
typedef ThreadSpecific<AssemblerData, WTF::CanBeGCThread::True> ThreadSpecificAssemblerData;
JS_EXPORT_PRIVATE ThreadSpecificAssemblerData& threadSpecificAssemblerData();
JS_EXPORT_PRIVATE ThreadSpecificAssemblerData& threadSpecificAssemblerHashes();
class LinkBuffer;
DECLARE_ALLOCATOR_WITH_HEAP_IDENTIFIER(AssemblerData);
struct AssemblerLabel {
inline AssemblerLabel() { setOffset(std::numeric_limits<uint32_t>::max()); }
inline AssemblerLabel(const AssemblerLabel& other) { setOffset(other.offset()); }
inline AssemblerLabel(AssemblerLabel&& other) { setOffset(other.offset()); }
inline explicit AssemblerLabel(uint32_t offset) { setOffset(offset); }
AssemblerLabel& operator=(const AssemblerLabel& other) { setOffset(other.offset()); return *this; }
AssemblerLabel& operator=(AssemblerLabel&& other) { setOffset(other.offset()); return *this; }
bool isSet() const { return (offset() != std::numeric_limits<uint32_t>::max()); }
inline AssemblerLabel labelAtOffset(int offset) const
{
return AssemblerLabel(this->offset() + offset);
}
bool operator==(const AssemblerLabel& other) const { return offset() == other.offset(); }
inline uint32_t offset() const
{
#if CPU(ARM64E)
return static_cast<uint32_t>(untagInt(m_offset, bitwise_cast<PtrTag>(this)));
#else
return m_offset;
#endif
}
private:
inline void setOffset(uint32_t offset)
{
#if CPU(ARM64E)
m_offset = tagInt(static_cast<uint64_t>(offset), bitwise_cast<PtrTag>(this));
#else
m_offset = offset;
#endif
}
#if CPU(ARM64E)
uint64_t m_offset;
#else
uint32_t m_offset;
#endif
};
class AssemblerData {
WTF_MAKE_NONCOPYABLE(AssemblerData);
static constexpr size_t InlineCapacity = 128;
public:
AssemblerData()
: m_buffer(m_inlineBuffer)
, m_capacity(InlineCapacity)
{
}
AssemblerData(size_t initialCapacity)
{
if (initialCapacity <= InlineCapacity) {
m_capacity = InlineCapacity;
m_buffer = m_inlineBuffer;
} else {
m_capacity = initialCapacity;
m_buffer = static_cast<char*>(AssemblerDataMalloc::malloc(m_capacity));
}
}
AssemblerData(AssemblerData&& other)
{
if (other.isInlineBuffer()) {
ASSERT(other.m_capacity == InlineCapacity);
memcpy(m_inlineBuffer, other.m_inlineBuffer, InlineCapacity);
m_buffer = m_inlineBuffer;
} else
m_buffer = other.m_buffer;
m_capacity = other.m_capacity;
other.m_buffer = other.m_inlineBuffer;
other.m_capacity = InlineCapacity;
}
AssemblerData& operator=(AssemblerData&& other)
{
if (m_buffer && !isInlineBuffer())
AssemblerDataMalloc::free(m_buffer);
if (other.isInlineBuffer()) {
ASSERT(other.m_capacity == InlineCapacity);
memcpy(m_inlineBuffer, other.m_inlineBuffer, InlineCapacity);
m_buffer = m_inlineBuffer;
} else
m_buffer = other.m_buffer;
m_capacity = other.m_capacity;
other.m_buffer = other.m_inlineBuffer;
other.m_capacity = InlineCapacity;
return *this;
}
void takeBufferIfLarger(AssemblerData&& other)
{
if (other.isInlineBuffer())
return;
if (m_capacity >= other.m_capacity)
return;
if (m_buffer && !isInlineBuffer())
AssemblerDataMalloc::free(m_buffer);
m_buffer = other.m_buffer;
m_capacity = other.m_capacity;
other.m_buffer = other.m_inlineBuffer;
other.m_capacity = InlineCapacity;
}
~AssemblerData()
{
clear();
}
void clear()
{
if (m_buffer && !isInlineBuffer()) {
AssemblerDataMalloc::free(m_buffer);
m_capacity = InlineCapacity;
m_buffer = m_inlineBuffer;
}
}
char* buffer() const { return m_buffer; }
unsigned capacity() const { return m_capacity; }
void grow(unsigned extraCapacity = 0)
{
m_capacity = m_capacity + m_capacity / 2 + extraCapacity;
if (isInlineBuffer()) {
m_buffer = static_cast<char*>(AssemblerDataMalloc::malloc(m_capacity));
memcpy(m_buffer, m_inlineBuffer, InlineCapacity);
} else
m_buffer = static_cast<char*>(AssemblerDataMalloc::realloc(m_buffer, m_capacity));
}
private:
bool isInlineBuffer() const { return m_buffer == m_inlineBuffer; }
char* m_buffer;
char m_inlineBuffer[InlineCapacity];
unsigned m_capacity;
};
#if CPU(ARM64E)
enum class ShouldSign {
Yes,
No
};
template <ShouldSign shouldSign>
class ARM64EHash {
WTF_MAKE_NONCOPYABLE(ARM64EHash);
public:
ARM64EHash()
{
allocatePinForCurrentThreadAndInitializeHash();
}
~ARM64EHash()
{
deallocatePinForCurrentThread();
}
ALWAYS_INLINE void allocatePinForCurrentThreadAndInitializeHash()
{
if constexpr (shouldSign == ShouldSign::Yes) {
m_initializedPin = true;
g_jscConfig.arm64eHashPins.allocatePinForCurrentThread();
setUpdatedHash(0, 0);
} else
m_hash = 0;
}
void deallocatePinForCurrentThread()
{
if (m_initializedPin) {
g_jscConfig.arm64eHashPins.deallocatePinForCurrentThread();
m_initializedPin = false;
}
}
ALWAYS_INLINE uint32_t update(uint32_t instruction, uint32_t index)
{
uint32_t currentHash = this->currentHash(index);
uint64_t nextIndex = index + 1;
uint32_t output = nextValue(instruction, nextIndex, currentHash);
setUpdatedHash(output, nextIndex);
return output;
}
private:
static constexpr uint8_t initializationNamespace = 0x11;
static ALWAYS_INLINE PtrTag makeDiversifier(uint8_t namespaceTag, uint64_t index, uint32_t value)
{
// <namespaceTag:8><index:24><value:32>
return static_cast<PtrTag>((static_cast<uint64_t>(namespaceTag) << 56) + ((index & 0xFFFFFF) << 32) + value);
}
static ALWAYS_INLINE uint32_t nextValue(uint64_t instruction, uint64_t index, uint32_t currentValue)
{
uint64_t a = tagInt(instruction, makeDiversifier(0x12, index, currentValue));
uint64_t b = tagInt(instruction, makeDiversifier(0x13, index, currentValue));
return (a >> 39) ^ (b >> 23);
}
static ALWAYS_INLINE uint32_t pin()
{
return g_jscConfig.arm64eHashPins.pinForCurrentThread();
}
ALWAYS_INLINE uint32_t currentHash(uint32_t index)
{
if constexpr (shouldSign == ShouldSign::Yes)
return untagInt(m_hash, makeDiversifier(initializationNamespace, index, pin()));
return m_hash;
}
ALWAYS_INLINE void setUpdatedHash(uint32_t value, uint32_t index)
{
if constexpr (shouldSign == ShouldSign::Yes)
m_hash = tagInt(static_cast<uint64_t>(value), makeDiversifier(initializationNamespace, index, pin()));
else
m_hash = static_cast<uint64_t>(value);
}
uint64_t m_hash;
bool m_initializedPin { false };
};
#endif // CPU(ARM64E)
class AssemblerBuffer {
public:
AssemblerBuffer()
: m_storage()
, m_index(0)
#if CPU(ARM64E)
, m_hash()
, m_hashes()
#endif
{
auto& threadSpecificData = threadSpecificAssemblerData();
m_storage.takeBufferIfLarger(WTFMove(*threadSpecificData));
#if CPU(ARM64E)
auto& threadSpecificHashes = threadSpecificAssemblerHashes();
m_hashes.takeBufferIfLarger(WTFMove(*threadSpecificHashes));
ASSERT(m_storage.capacity() == m_hashes.capacity());
#endif
}
~AssemblerBuffer()
{
#if CPU(ARM64E)
ASSERT(m_storage.capacity() == m_hashes.capacity());
auto& threadSpecificHashes = threadSpecificAssemblerHashes();
threadSpecificHashes->takeBufferIfLarger(WTFMove(m_hashes));
#endif
auto& threadSpecificData = threadSpecificAssemblerData();
threadSpecificData->takeBufferIfLarger(WTFMove(m_storage));
}
bool isAvailable(unsigned space)
{
return m_index + space <= m_storage.capacity();
}
void ensureSpace(unsigned space)
{
while (!isAvailable(space))
outOfLineGrow();
}
bool isAligned(int alignment) const
{
return !(m_index & (alignment - 1));
}
#if !CPU(ARM64)
void putByteUnchecked(int8_t value) { putIntegralUnchecked(value); }
void putByte(int8_t value) { putIntegral(value); }
void putShortUnchecked(int16_t value) { putIntegralUnchecked(value); }
void putShort(int16_t value) { putIntegral(value); }
void putInt64Unchecked(int64_t value) { putIntegralUnchecked(value); }
void putInt64(int64_t value) { putIntegral(value); }
#endif
void putIntUnchecked(int32_t value) { putIntegralUnchecked(value); }
void putInt(int32_t value) { putIntegral(value); }
size_t codeSize() const
{
return m_index;
}
#if !CPU(ARM64)
void setCodeSize(size_t index)
{
// Warning: Only use this if you know exactly what you are doing.
// For example, say you want 40 bytes of nops, it's ok to grow
// and then fill 40 bytes of nops using bigger instructions.
m_index = index;
ASSERT(m_index <= m_storage.capacity());
}
#endif
AssemblerLabel label() const
{
return AssemblerLabel(m_index);
}
unsigned debugOffset() { return m_index; }
AssemblerData&& releaseAssemblerData()
{
return WTFMove(m_storage);
}
#if CPU(ARM64E)
AssemblerData&& releaseAssemblerHashes()
{
return WTFMove(m_hashes);
}
#endif
// LocalWriter is a trick to keep the storage buffer and the index
// in memory while issuing multiple Stores.
// It is created in a block scope and its attribute can stay live
// between writes.
//
// LocalWriter *CANNOT* be mixed with other types of access to AssemblerBuffer.
// AssemblerBuffer cannot be used until its LocalWriter goes out of scope.
#if !CPU(ARM64) // If we ever need to use this on arm64e, we would need to make the checksum aware of this.
class LocalWriter {
public:
LocalWriter(AssemblerBuffer& buffer, unsigned requiredSpace)
: m_buffer(buffer)
{
buffer.ensureSpace(requiredSpace);
m_storageBuffer = buffer.m_storage.buffer();
m_index = buffer.m_index;
#if ASSERT_ENABLED
m_initialIndex = m_index;
m_requiredSpace = requiredSpace;
#endif
}
~LocalWriter()
{
ASSERT(m_index - m_initialIndex <= m_requiredSpace);
ASSERT(m_buffer.m_index == m_initialIndex);
ASSERT(m_storageBuffer == m_buffer.m_storage.buffer());
m_buffer.m_index = m_index;
}
void putByteUnchecked(int8_t value) { putIntegralUnchecked(value); }
void putShortUnchecked(int16_t value) { putIntegralUnchecked(value); }
void putIntUnchecked(int32_t value) { putIntegralUnchecked(value); }
void putInt64Unchecked(int64_t value) { putIntegralUnchecked(value); }
private:
template<typename IntegralType>
void putIntegralUnchecked(IntegralType value)
{
ASSERT(m_index + sizeof(IntegralType) <= m_buffer.m_storage.capacity());
WTF::unalignedStore<IntegralType>(m_storageBuffer + m_index, value);
m_index += sizeof(IntegralType);
}
AssemblerBuffer& m_buffer;
char* m_storageBuffer;
unsigned m_index;
#if ASSERT_ENABLED
unsigned m_initialIndex;
unsigned m_requiredSpace;
#endif
};
#endif // !CPU(ARM64)
#if !CPU(ARM64) // If we were to define this on arm64e, we'd need a way to update the hash as we write directly into the buffer.
void* data() const { return m_storage.buffer(); }
#endif
#if CPU(ARM64E)
ARM64EHash<ShouldSign::Yes>& arm64eHash() { return m_hash; }
#endif
protected:
template<typename IntegralType>
void putIntegral(IntegralType value)
{
unsigned nextIndex = m_index + sizeof(IntegralType);
if (UNLIKELY(nextIndex > m_storage.capacity()))
outOfLineGrow();
putIntegralUnchecked<IntegralType>(value);
}
template<typename IntegralType>
void putIntegralUnchecked(IntegralType value)
{
#if CPU(ARM64)
static_assert(sizeof(value) == 4);
#if CPU(ARM64E)
uint32_t hash = m_hash.update(value, m_index / sizeof(IntegralType));
WTF::unalignedStore<uint32_t>(m_hashes.buffer() + m_index, hash);
#endif
#endif
ASSERT(isAvailable(sizeof(IntegralType)));
WTF::unalignedStore<IntegralType>(m_storage.buffer() + m_index, value);
m_index += sizeof(IntegralType);
}
private:
void grow(int extraCapacity = 0)
{
m_storage.grow(extraCapacity);
#if CPU(ARM64E)
m_hashes.grow(extraCapacity);
#endif
}
NEVER_INLINE void outOfLineGrow()
{
m_storage.grow();
#if CPU(ARM64E)
m_hashes.grow();
#endif
}
#if !CPU(ARM64)
friend LocalWriter;
#endif
friend LinkBuffer;
AssemblerData m_storage;
unsigned m_index;
#if CPU(ARM64E)
ARM64EHash<ShouldSign::Yes> m_hash;
AssemblerData m_hashes;
#endif
};
} // namespace JSC
#endif // ENABLE(ASSEMBLER)