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/*
* Copyright (C) 2022-2023 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 CPU(ARM64E) && ENABLE(JIT)
#include <wtf/BitSet.h>
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
class SecureARM64EHashPins {
public:
JS_EXPORT_PRIVATE void initializeAtStartup();
JS_EXPORT_PRIVATE void allocatePinForCurrentThread();
JS_EXPORT_PRIVATE void deallocatePinForCurrentThread();
uint64_t pinForCurrentThread();
static constexpr size_t numEntriesPerPage = 64;
struct Entry {
uint64_t pin;
uint64_t key;
};
struct alignas(alignof(Entry)) Page {
Page();
static size_t allocationSize() { return sizeof(Page) + numEntriesPerPage * sizeof(Entry); }
static constexpr size_t mask = numEntriesPerPage - 1;
static_assert(hasOneBitSet(numEntriesPerPage));
static_assert(!!mask);
static_assert(!(mask & numEntriesPerPage));
ALWAYS_INLINE Entry& entry(size_t index)
{
return entries()[index & mask];
}
ALWAYS_INLINE Entry& fastEntryUnchecked(size_t index)
{
ASSERT((index & mask) == index);
return entries()[index];
}
ALWAYS_INLINE void setIsInUse(size_t index)
{
isInUseMap.set(index & mask);
}
ALWAYS_INLINE void clearIsInUse(size_t index)
{
isInUseMap.set(index & mask, false);
}
ALWAYS_INLINE bool isInUse(size_t index)
{
return isInUseMap.get(index & mask);
}
ALWAYS_INLINE size_t findClearBit()
{
return isInUseMap.findBit(0, false);
}
template <typename Function>
ALWAYS_INLINE void forEachSetBit(Function function)
{
isInUseMap.forEachSetBit(function);
}
Page* next { nullptr };
private:
Entry* entries() { return std::bit_cast<Entry*>(this + 1); }
WTF::BitSet<numEntriesPerPage> isInUseMap;
};
static_assert(sizeof(Page) % alignof(Entry) == 0);
struct alignas(alignof(Page)) Metadata {
Atomic<uint64_t> nextPin { 1 };
Atomic<uint32_t> assertNotReentrant { 0 };
};
static_assert(sizeof(Metadata) % alignof(Page) == 0);
private:
static uint64_t keyForCurrentThread();
bool allocatePinForCurrentThreadImpl(const AbstractLocker&);
struct FindResult {
Entry* entry { nullptr };
size_t index { std::numeric_limits<size_t>::max() };
Page* page { nullptr };
};
FindResult findFirstEntry();
Metadata* metadata();
inline Page* firstPage() { return std::bit_cast<Page*>(m_memory); }
template <typename Function>
void forEachPage(Function);
template <typename Function>
void forEachEntry(Function);
void* m_memory { nullptr };
};
} // namespace JSC
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
#endif // CPU(ARM64E) && ENABLE(JIT)
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