suyu/src/core/hle/kernel/thread.cpp
Fernando Sahmkow 103f3a2fe5 Scheduler: Add protections for Yield bombing
In case of redundant yields, the scheduler will now idle the core for 
it's timeslice, in order to avoid continuously yielding the same thing 
over and over.
2019-10-15 11:55:13 -04:00

550 lines
19 KiB
C++

// Copyright 2014 Citra Emulator Project / PPSSPP Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <algorithm>
#include <cinttypes>
#include <optional>
#include <vector>
#include "common/assert.h"
#include "common/common_types.h"
#include "common/logging/log.h"
#include "common/thread_queue_list.h"
#include "core/arm/arm_interface.h"
#include "core/core.h"
#include "core/core_cpu.h"
#include "core/core_timing.h"
#include "core/core_timing_util.h"
#include "core/hle/kernel/errors.h"
#include "core/hle/kernel/handle_table.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/object.h"
#include "core/hle/kernel/process.h"
#include "core/hle/kernel/scheduler.h"
#include "core/hle/kernel/thread.h"
#include "core/hle/result.h"
#include "core/memory.h"
namespace Kernel {
bool Thread::ShouldWait(const Thread* thread) const {
return status != ThreadStatus::Dead;
}
void Thread::Acquire(Thread* thread) {
ASSERT_MSG(!ShouldWait(thread), "object unavailable!");
}
Thread::Thread(KernelCore& kernel) : WaitObject{kernel} {}
Thread::~Thread() = default;
void Thread::Stop() {
// Cancel any outstanding wakeup events for this thread
Core::System::GetInstance().CoreTiming().UnscheduleEvent(kernel.ThreadWakeupCallbackEventType(),
callback_handle);
kernel.ThreadWakeupCallbackHandleTable().Close(callback_handle);
callback_handle = 0;
SetStatus(ThreadStatus::Dead);
WakeupAllWaitingThreads();
// Clean up any dangling references in objects that this thread was waiting for
for (auto& wait_object : wait_objects) {
wait_object->RemoveWaitingThread(this);
}
wait_objects.clear();
owner_process->UnregisterThread(this);
// Mark the TLS slot in the thread's page as free.
owner_process->FreeTLSRegion(tls_address);
}
void Thread::WakeAfterDelay(s64 nanoseconds) {
// Don't schedule a wakeup if the thread wants to wait forever
if (nanoseconds == -1)
return;
// This function might be called from any thread so we have to be cautious and use the
// thread-safe version of ScheduleEvent.
const s64 cycles = Core::Timing::nsToCycles(std::chrono::nanoseconds{nanoseconds});
Core::System::GetInstance().CoreTiming().ScheduleEvent(
cycles, kernel.ThreadWakeupCallbackEventType(), callback_handle);
}
void Thread::CancelWakeupTimer() {
Core::System::GetInstance().CoreTiming().UnscheduleEvent(kernel.ThreadWakeupCallbackEventType(),
callback_handle);
}
static std::optional<s32> GetNextProcessorId(u64 mask) {
for (s32 index = 0; index < Core::NUM_CPU_CORES; ++index) {
if (mask & (1ULL << index)) {
if (!Core::System::GetInstance().Scheduler(index).GetCurrentThread()) {
// Core is enabled and not running any threads, use this one
return index;
}
}
}
return {};
}
void Thread::ResumeFromWait() {
ASSERT_MSG(wait_objects.empty(), "Thread is waking up while waiting for objects");
switch (status) {
case ThreadStatus::WaitSynch:
case ThreadStatus::WaitHLEEvent:
case ThreadStatus::WaitSleep:
case ThreadStatus::WaitIPC:
case ThreadStatus::WaitMutex:
case ThreadStatus::WaitCondVar:
case ThreadStatus::WaitArb:
break;
case ThreadStatus::Ready:
// The thread's wakeup callback must have already been cleared when the thread was first
// awoken.
ASSERT(wakeup_callback == nullptr);
// If the thread is waiting on multiple wait objects, it might be awoken more than once
// before actually resuming. We can ignore subsequent wakeups if the thread status has
// already been set to ThreadStatus::Ready.
return;
case ThreadStatus::Running:
DEBUG_ASSERT_MSG(false, "Thread with object id {} has already resumed.", GetObjectId());
return;
case ThreadStatus::Dead:
// This should never happen, as threads must complete before being stopped.
DEBUG_ASSERT_MSG(false, "Thread with object id {} cannot be resumed because it's DEAD.",
GetObjectId());
return;
}
wakeup_callback = nullptr;
if (activity == ThreadActivity::Paused) {
SetStatus(ThreadStatus::Paused);
return;
}
SetStatus(ThreadStatus::Ready);
}
void Thread::CancelWait() {
ASSERT(GetStatus() == ThreadStatus::WaitSynch);
SetWaitSynchronizationResult(ERR_SYNCHRONIZATION_CANCELED);
ResumeFromWait();
}
/**
* Resets a thread context, making it ready to be scheduled and run by the CPU
* @param context Thread context to reset
* @param stack_top Address of the top of the stack
* @param entry_point Address of entry point for execution
* @param arg User argument for thread
*/
static void ResetThreadContext(Core::ARM_Interface::ThreadContext& context, VAddr stack_top,
VAddr entry_point, u64 arg) {
context = {};
context.cpu_registers[0] = arg;
context.pc = entry_point;
context.sp = stack_top;
// TODO(merry): Perform a hardware test to determine the below value.
// AHP = 0, DN = 1, FTZ = 1, RMode = Round towards zero
context.fpcr = 0x03C00000;
}
ResultVal<SharedPtr<Thread>> Thread::Create(KernelCore& kernel, std::string name, VAddr entry_point,
u32 priority, u64 arg, s32 processor_id,
VAddr stack_top, Process& owner_process) {
// Check if priority is in ranged. Lowest priority -> highest priority id.
if (priority > THREADPRIO_LOWEST) {
LOG_ERROR(Kernel_SVC, "Invalid thread priority: {}", priority);
return ERR_INVALID_THREAD_PRIORITY;
}
if (processor_id > THREADPROCESSORID_MAX) {
LOG_ERROR(Kernel_SVC, "Invalid processor id: {}", processor_id);
return ERR_INVALID_PROCESSOR_ID;
}
if (!Memory::IsValidVirtualAddress(owner_process, entry_point)) {
LOG_ERROR(Kernel_SVC, "(name={}): invalid entry {:016X}", name, entry_point);
// TODO (bunnei): Find the correct error code to use here
return ResultCode(-1);
}
auto& system = Core::System::GetInstance();
SharedPtr<Thread> thread(new Thread(kernel));
thread->thread_id = kernel.CreateNewThreadID();
thread->status = ThreadStatus::Dormant;
thread->entry_point = entry_point;
thread->stack_top = stack_top;
thread->tpidr_el0 = 0;
thread->nominal_priority = thread->current_priority = priority;
thread->last_running_ticks = system.CoreTiming().GetTicks();
thread->processor_id = processor_id;
thread->ideal_core = processor_id;
thread->affinity_mask = 1ULL << processor_id;
thread->wait_objects.clear();
thread->mutex_wait_address = 0;
thread->condvar_wait_address = 0;
thread->wait_handle = 0;
thread->name = std::move(name);
thread->callback_handle = kernel.ThreadWakeupCallbackHandleTable().Create(thread).Unwrap();
thread->owner_process = &owner_process;
auto& scheduler = kernel.GlobalScheduler();
scheduler.AddThread(thread);
thread->tls_address = thread->owner_process->CreateTLSRegion();
thread->owner_process->RegisterThread(thread.get());
// TODO(peachum): move to ScheduleThread() when scheduler is added so selected core is used
// to initialize the context
ResetThreadContext(thread->context, stack_top, entry_point, arg);
return MakeResult<SharedPtr<Thread>>(std::move(thread));
}
void Thread::SetPriority(u32 priority) {
ASSERT_MSG(priority <= THREADPRIO_LOWEST && priority >= THREADPRIO_HIGHEST,
"Invalid priority value.");
nominal_priority = priority;
UpdatePriority();
}
void Thread::SetWaitSynchronizationResult(ResultCode result) {
context.cpu_registers[0] = result.raw;
}
void Thread::SetWaitSynchronizationOutput(s32 output) {
context.cpu_registers[1] = output;
}
s32 Thread::GetWaitObjectIndex(const WaitObject* object) const {
ASSERT_MSG(!wait_objects.empty(), "Thread is not waiting for anything");
const auto match = std::find(wait_objects.rbegin(), wait_objects.rend(), object);
return static_cast<s32>(std::distance(match, wait_objects.rend()) - 1);
}
VAddr Thread::GetCommandBufferAddress() const {
// Offset from the start of TLS at which the IPC command buffer begins.
constexpr u64 command_header_offset = 0x80;
return GetTLSAddress() + command_header_offset;
}
void Thread::SetStatus(ThreadStatus new_status) {
if (new_status == status) {
return;
}
switch (new_status) {
case ThreadStatus::Ready:
case ThreadStatus::Running:
SetSchedulingStatus(ThreadSchedStatus::Runnable);
break;
case ThreadStatus::Dormant:
SetSchedulingStatus(ThreadSchedStatus::None);
break;
case ThreadStatus::Dead:
SetSchedulingStatus(ThreadSchedStatus::Exited);
break;
default:
SetSchedulingStatus(ThreadSchedStatus::Paused);
break;
}
if (status == ThreadStatus::Running) {
last_running_ticks = Core::System::GetInstance().CoreTiming().GetTicks();
}
status = new_status;
}
void Thread::AddMutexWaiter(SharedPtr<Thread> thread) {
if (thread->lock_owner == this) {
// If the thread is already waiting for this thread to release the mutex, ensure that the
// waiters list is consistent and return without doing anything.
const auto iter = std::find(wait_mutex_threads.begin(), wait_mutex_threads.end(), thread);
ASSERT(iter != wait_mutex_threads.end());
return;
}
// A thread can't wait on two different mutexes at the same time.
ASSERT(thread->lock_owner == nullptr);
// Ensure that the thread is not already in the list of mutex waiters
const auto iter = std::find(wait_mutex_threads.begin(), wait_mutex_threads.end(), thread);
ASSERT(iter == wait_mutex_threads.end());
// Keep the list in an ordered fashion
const auto insertion_point = std::find_if(
wait_mutex_threads.begin(), wait_mutex_threads.end(),
[&thread](const auto& entry) { return entry->GetPriority() > thread->GetPriority(); });
wait_mutex_threads.insert(insertion_point, thread);
thread->lock_owner = this;
UpdatePriority();
}
void Thread::RemoveMutexWaiter(SharedPtr<Thread> thread) {
ASSERT(thread->lock_owner == this);
// Ensure that the thread is in the list of mutex waiters
const auto iter = std::find(wait_mutex_threads.begin(), wait_mutex_threads.end(), thread);
ASSERT(iter != wait_mutex_threads.end());
wait_mutex_threads.erase(iter);
thread->lock_owner = nullptr;
UpdatePriority();
}
void Thread::UpdatePriority() {
// If any of the threads waiting on the mutex have a higher priority
// (taking into account priority inheritance), then this thread inherits
// that thread's priority.
u32 new_priority = nominal_priority;
if (!wait_mutex_threads.empty()) {
if (wait_mutex_threads.front()->current_priority < new_priority) {
new_priority = wait_mutex_threads.front()->current_priority;
}
}
if (new_priority == current_priority) {
return;
}
SetCurrentPriority(new_priority);
if (!lock_owner) {
return;
}
// Ensure that the thread is within the correct location in the waiting list.
auto old_owner = lock_owner;
lock_owner->RemoveMutexWaiter(this);
old_owner->AddMutexWaiter(this);
// Recursively update the priority of the thread that depends on the priority of this one.
lock_owner->UpdatePriority();
}
void Thread::ChangeCore(u32 core, u64 mask) {
SetCoreAndAffinityMask(core, mask);
}
bool Thread::AllWaitObjectsReady() const {
return std::none_of(
wait_objects.begin(), wait_objects.end(),
[this](const SharedPtr<WaitObject>& object) { return object->ShouldWait(this); });
}
bool Thread::InvokeWakeupCallback(ThreadWakeupReason reason, SharedPtr<Thread> thread,
SharedPtr<WaitObject> object, std::size_t index) {
ASSERT(wakeup_callback);
return wakeup_callback(reason, std::move(thread), std::move(object), index);
}
void Thread::SetActivity(ThreadActivity value) {
activity = value;
if (value == ThreadActivity::Paused) {
// Set status if not waiting
if (status == ThreadStatus::Ready) {
status = ThreadStatus::Paused;
} else if (status == ThreadStatus::Running) {
SetStatus(ThreadStatus::Paused);
Core::System::GetInstance().CpuCore(processor_id).PrepareReschedule();
}
} else if (status == ThreadStatus::Paused) {
// Ready to reschedule
ResumeFromWait();
}
}
void Thread::Sleep(s64 nanoseconds) {
// Sleep current thread and check for next thread to schedule
SetStatus(ThreadStatus::WaitSleep);
// Create an event to wake the thread up after the specified nanosecond delay has passed
WakeAfterDelay(nanoseconds);
}
bool Thread::YieldSimple() {
auto& scheduler = kernel.GlobalScheduler();
return scheduler.YieldThread(this);
}
bool Thread::YieldAndBalanceLoad() {
auto& scheduler = kernel.GlobalScheduler();
return scheduler.YieldThreadAndBalanceLoad(this);
}
bool Thread::YieldAndWaitForLoadBalancing() {
auto& scheduler = kernel.GlobalScheduler();
return scheduler.YieldThreadAndWaitForLoadBalancing(this);
}
void Thread::SetSchedulingStatus(ThreadSchedStatus new_status) {
const u32 old_flags = scheduling_state;
scheduling_state =
(scheduling_state & ThreadSchedMasks::HighMask) | static_cast<u32>(new_status);
AdjustSchedulingOnStatus(old_flags);
}
void Thread::SetCurrentPriority(u32 new_priority) {
u32 old_priority = std::exchange(current_priority, new_priority);
AdjustSchedulingOnPriority(old_priority);
}
ResultCode Thread::SetCoreAndAffinityMask(s32 new_core, u64 new_affinity_mask) {
const auto HighestSetCore = [](u64 mask, u32 max_cores) {
for (s32 core = max_cores - 1; core >= 0; core--) {
if (((mask >> core) & 1) != 0) {
return core;
}
}
return -1;
};
const bool use_override = affinity_override_count != 0;
// The value -3 is "do not change the ideal core".
if (new_core == -3) {
new_core = use_override ? ideal_core_override : ideal_core;
if ((new_affinity_mask & (1 << new_core)) == 0) {
return ERR_INVALID_COMBINATION;
}
}
if (use_override) {
ideal_core_override = new_core;
affinity_mask_override = new_affinity_mask;
} else {
const u64 old_affinity_mask = std::exchange(affinity_mask, new_affinity_mask);
ideal_core = new_core;
if (old_affinity_mask != new_affinity_mask) {
const s32 old_core = processor_id;
if (processor_id >= 0 && ((affinity_mask >> processor_id) & 1) == 0) {
if (ideal_core < 0) {
processor_id = HighestSetCore(affinity_mask, GlobalScheduler::NUM_CPU_CORES);
} else {
processor_id = ideal_core;
}
}
AdjustSchedulingOnAffinity(old_affinity_mask, old_core);
}
}
return RESULT_SUCCESS;
}
void Thread::AdjustSchedulingOnStatus(u32 old_flags) {
if (old_flags == scheduling_state) {
return;
}
auto& scheduler = kernel.GlobalScheduler();
if (static_cast<ThreadSchedStatus>(old_flags & ThreadSchedMasks::LowMask) ==
ThreadSchedStatus::Runnable) {
// In this case the thread was running, now it's pausing/exitting
if (processor_id >= 0) {
scheduler.Unschedule(current_priority, processor_id, this);
}
for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
if (core != processor_id && ((affinity_mask >> core) & 1) != 0) {
scheduler.Unsuggest(current_priority, core, this);
}
}
} else if (GetSchedulingStatus() == ThreadSchedStatus::Runnable) {
// The thread is now set to running from being stopped
if (processor_id >= 0) {
scheduler.Schedule(current_priority, processor_id, this);
}
for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
if (core != processor_id && ((affinity_mask >> core) & 1) != 0) {
scheduler.Suggest(current_priority, core, this);
}
}
}
scheduler.SetReselectionPending();
}
void Thread::AdjustSchedulingOnPriority(u32 old_priority) {
if (GetSchedulingStatus() != ThreadSchedStatus::Runnable) {
return;
}
auto& scheduler = Core::System::GetInstance().GlobalScheduler();
if (processor_id >= 0) {
scheduler.Unschedule(old_priority, processor_id, this);
}
for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
if (core != processor_id && ((affinity_mask >> core) & 1) != 0) {
scheduler.Unsuggest(old_priority, core, this);
}
}
// Add thread to the new priority queues.
Thread* current_thread = GetCurrentThread();
if (processor_id >= 0) {
if (current_thread == this) {
scheduler.SchedulePrepend(current_priority, processor_id, this);
} else {
scheduler.Schedule(current_priority, processor_id, this);
}
}
for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
if (core != processor_id && ((affinity_mask >> core) & 1) != 0) {
scheduler.Suggest(current_priority, core, this);
}
}
scheduler.SetReselectionPending();
}
void Thread::AdjustSchedulingOnAffinity(u64 old_affinity_mask, s32 old_core) {
auto& scheduler = Core::System::GetInstance().GlobalScheduler();
if (GetSchedulingStatus() != ThreadSchedStatus::Runnable ||
current_priority >= THREADPRIO_COUNT) {
return;
}
for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
if (((old_affinity_mask >> core) & 1) != 0) {
if (core == old_core) {
scheduler.Unschedule(current_priority, core, this);
} else {
scheduler.Unsuggest(current_priority, core, this);
}
}
}
for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
if (((affinity_mask >> core) & 1) != 0) {
if (core == processor_id) {
scheduler.Schedule(current_priority, core, this);
} else {
scheduler.Suggest(current_priority, core, this);
}
}
}
scheduler.SetReselectionPending();
}
////////////////////////////////////////////////////////////////////////////////////////////////////
/**
* Gets the current thread
*/
Thread* GetCurrentThread() {
return Core::System::GetInstance().CurrentScheduler().GetCurrentThread();
}
} // namespace Kernel