// Copyright 2018 yuzu emulator team
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include "common/assert.h"
#include "common/common_funcs.h"
#include "common/common_types.h"
#include "core/core.h"
#include "core/hle/kernel/errors.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/process.h"
#include "core/hle/kernel/thread.h"
#include "core/hle/lock.h"
#include "core/memory.h"
namespace Kernel {
namespace AddressArbiter {
// Performs actual address waiting logic.
ResultCode WaitForAddress(VAddr address, s64 timeout) {
SharedPtr<Thread> current_thread = GetCurrentThread();
current_thread->arb_wait_address = address;
current_thread->arb_wait_result = RESULT_TIMEOUT;
current_thread->status = THREADSTATUS_WAIT_ARB;
current_thread->wakeup_callback = nullptr;
current_thread->WakeAfterDelay(timeout);
Core::System::GetInstance().CpuCore(current_thread->processor_id).PrepareReschedule();
return current_thread->arb_wait_result;
}
// Gets the threads waiting on an address.
void GetThreadsWaitingOnAddress(std::vector<SharedPtr<Thread>> &waiting_threads, VAddr address) {
auto RetrieveWaitingThreads =
[](size_t core_index, std::vector<SharedPtr<Thread>>& waiting_threads, VAddr arb_addr) {
const auto& scheduler = Core::System::GetInstance().Scheduler(core_index);
auto& thread_list = scheduler->GetThreadList();
for (auto& thread : thread_list) {
if (thread->arb_wait_address == arb_addr)
waiting_threads.push_back(thread);
}
};
// Retrieve a list of all threads that are waiting for this address.
RetrieveWaitingThreads(0, waiting_threads, address);
RetrieveWaitingThreads(1, waiting_threads, address);
RetrieveWaitingThreads(2, waiting_threads, address);
RetrieveWaitingThreads(3, waiting_threads, address);
// Sort them by priority, such that the highest priority ones come first.
std::sort(waiting_threads.begin(), waiting_threads.end(),
[](const SharedPtr<Thread>& lhs, const SharedPtr<Thread>& rhs) {
return lhs->current_priority < rhs->current_priority;
});
}
// Wake up num_to_wake (or all) threads in a vector.
void WakeThreads(std::vector<SharedPtr<Thread>> &waiting_threads, s32 num_to_wake) {
// Only process up to 'target' threads, unless 'target' is <= 0, in which case process
// them all.
size_t last = waiting_threads.size();
if (num_to_wake > 0)
last = num_to_wake;
// Signal the waiting threads.
// TODO: Rescheduling should not occur while waking threads. How can it be prevented?
for (size_t i = 0; i < last; i++) {
ASSERT(waiting_threads[i]->status = THREADSTATUS_WAIT_ARB);
waiting_threads[i]->arb_wait_result = RESULT_SUCCESS;
waiting_threads[i]->arb_wait_address = 0;
waiting_threads[i]->ResumeFromWait();
}
}
// Signals an address being waited on.
ResultCode SignalToAddress(VAddr address, s32 num_to_wake) {
// Get threads waiting on the address.
std::vector<SharedPtr<Thread>> waiting_threads;
GetThreadsWaitingOnAddress(waiting_threads, address);
WakeThreads(waiting_threads, num_to_wake);
return RESULT_SUCCESS;
}
// Signals an address being waited on and increments its value if equal to the value argument.
ResultCode IncrementAndSignalToAddressIfEqual(VAddr address, s32 value, s32 num_to_wake) {
// Ensure that we can write to the address.
if (!Memory::IsValidVirtualAddress(address)) {
return ERR_INVALID_ADDRESS_STATE;
}
s32 cur_value;
// Get value, incrementing if equal.
{
// Increment if Equal must be an atomic operation.
std::lock_guard<std::recursive_mutex> lock(HLE::g_hle_lock);
cur_value = (s32)Memory::Read32(address);
if (cur_value == value) {
Memory::Write32(address, (u32)(cur_value + 1));
}
}
if (cur_value != value) {
return ERR_INVALID_STATE;
}
return SignalToAddress(address, num_to_wake);
}
// Signals an address being waited on and modifies its value based on waiting thread count if equal to the value argument.
ResultCode ModifyByWaitingCountAndSignalToAddressIfEqual(VAddr address, s32 value, s32 num_to_wake) {
// Ensure that we can write to the address.
if (!Memory::IsValidVirtualAddress(address)) {
return ERR_INVALID_ADDRESS_STATE;
}
// Get threads waiting on the address.
std::vector<SharedPtr<Thread>> waiting_threads;
GetThreadsWaitingOnAddress(waiting_threads, address);
// Determine the modified value depending on the waiting count.
s32 updated_value;
if (waiting_threads.size() == 0) {
updated_value = value - 1;
} else if (num_to_wake <= 0 || waiting_threads.size() <= num_to_wake) {
updated_value = value + 1;
} else {
updated_value = value;
}
s32 cur_value;
// Perform an atomic update if equal.
{
std::lock_guard<std::recursive_mutex> lock(HLE::g_hle_lock);
cur_value = (s32)Memory::Read32(address);
if (cur_value == value) {
Memory::Write32(address, (u32)(updated_value));
}
}
// Only continue if equal.
if (cur_value != value) {
return ERR_INVALID_STATE;
}
WakeThreads(waiting_threads, num_to_wake);
return RESULT_SUCCESS;
}
// Waits on an address if the value passed is less than the argument value, optionally decrementing.
ResultCode WaitForAddressIfLessThan(VAddr address, s32 value, s64 timeout, bool should_decrement) {
// Ensure that we can read the address.
if (!Memory::IsValidVirtualAddress(address)) {
return ERR_INVALID_ADDRESS_STATE;
}
s32 cur_value;
// Get value, decrementing if less than
{
// Decrement if less than must be an atomic operation.
std::lock_guard<std::recursive_mutex> lock(HLE::g_hle_lock);
cur_value = (s32)Memory::Read32(address);
if (cur_value < value) {
Memory::Write32(address, (u32)(cur_value - 1));
}
}
if (cur_value >= value) {
return ERR_INVALID_STATE;
}
// Short-circuit without rescheduling, if timeout is zero.
if (timeout == 0) {
return RESULT_TIMEOUT;
}
return WaitForAddress(address, timeout);
}
// Waits on an address if the value passed is equal to the argument value.
ResultCode WaitForAddressIfEqual(VAddr address, s32 value, s64 timeout) {
// Ensure that we can read the address.
if (!Memory::IsValidVirtualAddress(address)) {
return ERR_INVALID_ADDRESS_STATE;
}
// Only wait for the address if equal.
if ((s32)Memory::Read32(address) != value) {
return ERR_INVALID_STATE;
}
// Short-circuit without rescheduling, if timeout is zero.
if (timeout == 0) {
return RESULT_TIMEOUT;
}
return WaitForAddress(address, timeout);
}
} // namespace AddressArbiter
} // namespace Kernel
