dynarmic/include/dynarmic/exclusive_monitor.h
2020-06-17 10:33:09 +01:00

81 lines
2.5 KiB
C++

/* This file is part of the dynarmic project.
* Copyright (c) 2018 MerryMage
* SPDX-License-Identifier: 0BSD
*/
#pragma once
#include <atomic>
#include <array>
#include <cstddef>
#include <cstdint>
#include <cstring>
#include <vector>
namespace Dynarmic {
using VAddr = std::uint64_t;
using Vector = std::array<std::uint64_t, 2>;
class ExclusiveMonitor {
public:
/// @param processor_count Maximum number of processors using this global
/// exclusive monitor. Each processor must have a
/// unique id.
explicit ExclusiveMonitor(size_t processor_count);
size_t GetProcessorCount() const;
/// Marks a region containing [address, address+size) to be exclusive to
/// processor processor_id.
template <typename T, typename Function>
T ReadAndMark(size_t processor_id, VAddr address, Function op) {
static_assert(std::is_trivially_copyable_v<T>);
const VAddr masked_address = address & RESERVATION_GRANULE_MASK;
Lock();
exclusive_addresses[processor_id] = masked_address;
const T value = op();
std::memcpy(exclusive_values[processor_id].data(), &value, sizeof(T));
Unlock();
return value;
}
/// Checks to see if processor processor_id has exclusive access to the
/// specified region. If it does, executes the operation then clears
/// the exclusive state for processors if their exclusive region(s)
/// contain [address, address+size).
template <typename T, typename Function>
bool DoExclusiveOperation(size_t processor_id, VAddr address, Function op) {
static_assert(std::is_trivially_copyable_v<T>);
if (!CheckAndClear(processor_id, address)) {
return false;
}
T saved_value;
std::memcpy(&saved_value, exclusive_values[processor_id].data(), sizeof(T));
const bool result = op(saved_value);
Unlock();
return result;
}
/// Unmark everything.
void Clear();
/// Unmark processor id
void ClearProcessor(size_t processor_id);
private:
bool CheckAndClear(size_t processor_id, VAddr address);
void Lock();
void Unlock();
static constexpr VAddr RESERVATION_GRANULE_MASK = 0xFFFF'FFFF'FFFF'FFFFull;
static constexpr VAddr INVALID_EXCLUSIVE_ADDRESS = 0xDEAD'DEAD'DEAD'DEADull;
std::atomic_flag is_locked;
std::vector<VAddr> exclusive_addresses;
std::vector<Vector> exclusive_values;
};
} // namespace Dynarmic