summaryrefslogtreecommitdiffstats
path: root/src/core/hle/kernel/thread.cpp
blob: 0a3fd7cb198042185d289cfef1e0cc78f9b4c521 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
// Copyright 2014 Citra Emulator Project / PPSSPP Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#include <algorithm>
#include <list>
#include <vector>

#include "common/assert.h"
#include "common/common_types.h"
#include "common/logging/log.h"
#include "common/math_util.h"
#include "common/thread_queue_list.h"

#include "core/arm/arm_interface.h"
#include "core/core.h"
#include "core/core_timing.h"
#include "core/hle/hle.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/thread.h"
#include "core/hle/kernel/mutex.h"
#include "core/hle/result.h"
#include "core/mem_map.h"

namespace Kernel {

/// Event type for the thread wake up event
static int ThreadWakeupEventType;

bool Thread::ShouldWait() {
    return status != THREADSTATUS_DEAD;
}

void Thread::Acquire() {
    ASSERT_MSG(!ShouldWait(), "object unavailable!");
}

// Lists all thread ids that aren't deleted/etc.
static std::vector<SharedPtr<Thread>> thread_list;

// Lists only ready thread ids.
static Common::ThreadQueueList<Thread*, THREADPRIO_LOWEST+1> ready_queue;

static Thread* current_thread;

// The first available thread id at startup
static u32 next_thread_id;

/**
 * Creates a new thread ID
 * @return The new thread ID
 */
inline static u32 const NewThreadId() {
    return next_thread_id++;
}

Thread::Thread() {}
Thread::~Thread() {}

Thread* GetCurrentThread() {
    return current_thread;
}

/**
 * Check if a thread is waiting on the specified wait object
 * @param thread The thread to test
 * @param wait_object The object to test against
 * @return True if the thread is waiting, false otherwise
 */
static bool CheckWait_WaitObject(const Thread* thread, WaitObject* wait_object) {
    if (thread->status != THREADSTATUS_WAIT_SYNCH)
        return false;

    auto itr = std::find(thread->wait_objects.begin(), thread->wait_objects.end(), wait_object);
    return itr != thread->wait_objects.end();
}

/**
 * Check if the specified thread is waiting on the specified address to be arbitrated
 * @param thread The thread to test
 * @param wait_address The address to test against
 * @return True if the thread is waiting, false otherwise
 */
static bool CheckWait_AddressArbiter(const Thread* thread, VAddr wait_address) {
    return thread->status == THREADSTATUS_WAIT_ARB && wait_address == thread->wait_address;
}

void Thread::Stop() {
    // Release all the mutexes that this thread holds
    ReleaseThreadMutexes(this);

    // Cancel any outstanding wakeup events for this thread
    CoreTiming::UnscheduleEvent(ThreadWakeupEventType, callback_handle);

    // Clean up thread from ready queue
    // This is only needed when the thread is termintated forcefully (SVC TerminateProcess)
    if (status == THREADSTATUS_READY){
        ready_queue.remove(current_priority, this);
    }

    status = 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);
    }
}

Thread* ArbitrateHighestPriorityThread(u32 address) {
    Thread* highest_priority_thread = nullptr;
    s32 priority = THREADPRIO_LOWEST;

    // Iterate through threads, find highest priority thread that is waiting to be arbitrated...
    for (auto& thread : thread_list) {
        if (!CheckWait_AddressArbiter(thread.get(), address))
            continue;

        if (thread == nullptr)
            continue;

        if(thread->current_priority <= priority) {
            highest_priority_thread = thread.get();
            priority = thread->current_priority;
        }
    }

    // If a thread was arbitrated, resume it
    if (nullptr != highest_priority_thread) {
        highest_priority_thread->ResumeFromWait();
    }

    return highest_priority_thread;
}

void ArbitrateAllThreads(u32 address) {
    // Resume all threads found to be waiting on the address
    for (auto& thread : thread_list) {
        if (CheckWait_AddressArbiter(thread.get(), address))
            thread->ResumeFromWait();
    }
}

/// Boost low priority threads (temporarily) that have been starved
static void PriorityBoostStarvedThreads() {
    u64 current_ticks = CoreTiming::GetTicks();

    for (auto& thread : thread_list) {
        // TODO(bunnei): Threads that have been waiting to be scheduled for `boost_ticks` (or
        // longer) will have their priority temporarily adjusted to 1 higher than the highest
        // priority thread to prevent thread starvation. This general behavior has been verified
        // on hardware. However, this is almost certainly not perfect, and the real CTR OS scheduler
        // should probably be reversed to verify this.

        const u64 boost_timeout = 2000000;  // Boost threads that have been ready for > this long

        u64 delta = current_ticks - thread->last_running_ticks;

        if (thread->status == THREADSTATUS_READY && delta > boost_timeout && !thread->idle) {
            const s32 priority = std::max(ready_queue.get_first()->current_priority - 1, 0);
            thread->BoostPriority(priority);
        }
    }
}

/** 
 * Switches the CPU's active thread context to that of the specified thread
 * @param new_thread The thread to switch to
 */
static void SwitchContext(Thread* new_thread) {
    DEBUG_ASSERT_MSG(new_thread->status == THREADSTATUS_READY, "Thread must be ready to become running.");

    Thread* previous_thread = GetCurrentThread();

    // Save context for previous thread
    if (previous_thread) {
        previous_thread->last_running_ticks = CoreTiming::GetTicks();
        Core::g_app_core->SaveContext(previous_thread->context);

        if (previous_thread->status == THREADSTATUS_RUNNING) {
            // This is only the case when a reschedule is triggered without the current thread
            // yielding execution (i.e. an event triggered, system core time-sliced, etc)
            ready_queue.push_front(previous_thread->current_priority, previous_thread);
            previous_thread->status = THREADSTATUS_READY;
        }
    }

    // Load context of new thread
    if (new_thread) {
        current_thread = new_thread;

        ready_queue.remove(new_thread->current_priority, new_thread);
        new_thread->status = THREADSTATUS_RUNNING;

        // Restores thread to its nominal priority if it has been temporarily changed
        new_thread->current_priority = new_thread->nominal_priority;

        Core::g_app_core->LoadContext(new_thread->context);
    } else {
        current_thread = nullptr;
    }
}

/**
 * Pops and returns the next thread from the thread queue
 * @return A pointer to the next ready thread
 */
static Thread* PopNextReadyThread() {
    Thread* next;
    Thread* thread = GetCurrentThread();

    if (thread && thread->status == THREADSTATUS_RUNNING) {
        // We have to do better than the current thread.
        // This call returns null when that's not possible.
        next = ready_queue.pop_first_better(thread->current_priority);
    } else  {
        next = ready_queue.pop_first();
    }

    return next;
}

void WaitCurrentThread_Sleep() {
    Thread* thread = GetCurrentThread();
    thread->status = THREADSTATUS_WAIT_SLEEP;
}

void WaitCurrentThread_WaitSynchronization(std::vector<SharedPtr<WaitObject>> wait_objects, bool wait_set_output, bool wait_all) {
    Thread* thread = GetCurrentThread();
    thread->wait_set_output = wait_set_output;
    thread->wait_all = wait_all;
    thread->wait_objects = std::move(wait_objects);
    thread->status = THREADSTATUS_WAIT_SYNCH;
}

void WaitCurrentThread_ArbitrateAddress(VAddr wait_address) {
    Thread* thread = GetCurrentThread();
    thread->wait_address = wait_address;
    thread->status = THREADSTATUS_WAIT_ARB;
}

// TODO(yuriks): This can be removed if Thread objects are explicitly pooled in the future, allowing
//               us to simply use a pool index or similar.
static Kernel::HandleTable wakeup_callback_handle_table;

/**
 * Callback that will wake up the thread it was scheduled for
 * @param thread_handle The handle of the thread that's been awoken
 * @param cycles_late The number of CPU cycles that have passed since the desired wakeup time
 */
static void ThreadWakeupCallback(u64 thread_handle, int cycles_late) {
    SharedPtr<Thread> thread = wakeup_callback_handle_table.Get<Thread>((Handle)thread_handle);
    if (thread == nullptr) {
        LOG_CRITICAL(Kernel, "Callback fired for invalid thread %08X", (Handle)thread_handle);
        return;
    }

    if (thread->status == THREADSTATUS_WAIT_SYNCH) {
        thread->SetWaitSynchronizationResult(ResultCode(ErrorDescription::Timeout, ErrorModule::OS,
                                                        ErrorSummary::StatusChanged, ErrorLevel::Info));

        if (thread->wait_set_output)
            thread->SetWaitSynchronizationOutput(-1);
    }

    thread->ResumeFromWait();
}

void Thread::WakeAfterDelay(s64 nanoseconds) {
    // Don't schedule a wakeup if the thread wants to wait forever
    if (nanoseconds == -1)
        return;

    u64 microseconds = nanoseconds / 1000;
    CoreTiming::ScheduleEvent(usToCycles(microseconds), ThreadWakeupEventType, callback_handle);
}

void Thread::ReleaseWaitObject(WaitObject* wait_object) {
    if (status != THREADSTATUS_WAIT_SYNCH || wait_objects.empty()) {
        LOG_CRITICAL(Kernel, "thread is not waiting on any objects!");
        return;
    }

    // Remove this thread from the waiting object's thread list
    wait_object->RemoveWaitingThread(this);

    unsigned index = 0;
    bool wait_all_failed = false; // Will be set to true if any object is unavailable

    // Iterate through all waiting objects to check availability...
    for (auto itr = wait_objects.begin(); itr != wait_objects.end(); ++itr) {
        if ((*itr)->ShouldWait())
            wait_all_failed = true;

        // The output should be the last index of wait_object
        if (*itr == wait_object)
            index = itr - wait_objects.begin();
    }

    // If we are waiting on all objects...
    if (wait_all) {
        // Resume the thread only if all are available...
        if (!wait_all_failed) {
            SetWaitSynchronizationResult(RESULT_SUCCESS);
            SetWaitSynchronizationOutput(-1);

            ResumeFromWait();
        }
    } else {
        // Otherwise, resume
        SetWaitSynchronizationResult(RESULT_SUCCESS);

        if (wait_set_output)
            SetWaitSynchronizationOutput(index);

        ResumeFromWait();
    }
}

void Thread::ResumeFromWait() {
    // Cancel any outstanding wakeup events for this thread
    CoreTiming::UnscheduleEvent(ThreadWakeupEventType, callback_handle);

    switch (status) {
        case THREADSTATUS_WAIT_SYNCH:
            // Remove this thread from all other WaitObjects
            for (auto wait_object : wait_objects)
                wait_object->RemoveWaitingThread(this);
            break;
        case THREADSTATUS_WAIT_ARB:
        case THREADSTATUS_WAIT_SLEEP:
            break;
        case THREADSTATUS_RUNNING:
        case THREADSTATUS_READY:
            DEBUG_ASSERT_MSG(false, "Thread with object id %u 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 %u cannot be resumed because it's DEAD.",
                GetObjectId());
            return;
    }
    
    ready_queue.push_back(current_priority, this);
    status = THREADSTATUS_READY;
}

/**
 * Prints the thread queue for debugging purposes
 */
static void DebugThreadQueue() {
    Thread* thread = GetCurrentThread();
    if (!thread) {
        LOG_DEBUG(Kernel, "Current: NO CURRENT THREAD");
    } else {
        LOG_DEBUG(Kernel, "0x%02X %u (current)", thread->current_priority, GetCurrentThread()->GetObjectId());
    }

    for (auto& t : thread_list) {
        s32 priority = ready_queue.contains(t.get());
        if (priority != -1) {
            LOG_DEBUG(Kernel, "0x%02X %u", priority, t->GetObjectId());
        }
    }
}

ResultVal<SharedPtr<Thread>> Thread::Create(std::string name, VAddr entry_point, s32 priority,
        u32 arg, s32 processor_id, VAddr stack_top) {
    if (priority < THREADPRIO_HIGHEST || priority > THREADPRIO_LOWEST) {
        s32 new_priority = MathUtil::Clamp<s32>(priority, THREADPRIO_HIGHEST, THREADPRIO_LOWEST);
        LOG_WARNING(Kernel_SVC, "(name=%s): invalid priority=%d, clamping to %d",
            name.c_str(), priority, new_priority);
        // TODO(bunnei): Clamping to a valid priority is not necessarily correct behavior... Confirm
        // validity of this
        priority = new_priority;
    }

    if (!Memory::GetPointer(entry_point)) {
        LOG_ERROR(Kernel_SVC, "(name=%s): invalid entry %08x", name.c_str(), entry_point);
        // TODO: Verify error
        return ResultCode(ErrorDescription::InvalidAddress, ErrorModule::Kernel,
                ErrorSummary::InvalidArgument, ErrorLevel::Permanent);
    }

    SharedPtr<Thread> thread(new Thread);

    thread_list.push_back(thread);
    ready_queue.prepare(priority);

    thread->thread_id = NewThreadId();
    thread->status = THREADSTATUS_DORMANT;
    thread->entry_point = entry_point;
    thread->stack_top = stack_top;
    thread->nominal_priority = thread->current_priority = priority;
    thread->last_running_ticks = CoreTiming::GetTicks();
    thread->processor_id = processor_id;
    thread->wait_set_output = false;
    thread->wait_all = false;
    thread->wait_objects.clear();
    thread->wait_address = 0;
    thread->name = std::move(name);
    thread->callback_handle = wakeup_callback_handle_table.Create(thread).MoveFrom();

    // TODO(peachum): move to ScheduleThread() when scheduler is added so selected core is used
    // to initialize the context
    Core::g_app_core->ResetContext(thread->context, stack_top, entry_point, arg);

    ready_queue.push_back(thread->current_priority, thread.get());
    thread->status = THREADSTATUS_READY;

    return MakeResult<SharedPtr<Thread>>(std::move(thread));
}

// TODO(peachum): Remove this. Range checking should be done, and an appropriate error should be returned.
static void ClampPriority(const Thread* thread, s32* priority) {
    if (*priority < THREADPRIO_HIGHEST || *priority > THREADPRIO_LOWEST) {
        DEBUG_ASSERT_MSG(false, "Application passed an out of range priority. An error should be returned.");

        s32 new_priority = MathUtil::Clamp<s32>(*priority, THREADPRIO_HIGHEST, THREADPRIO_LOWEST);
        LOG_WARNING(Kernel_SVC, "(name=%s): invalid priority=%d, clamping to %d",
                    thread->name.c_str(), *priority, new_priority);
        // TODO(bunnei): Clamping to a valid priority is not necessarily correct behavior... Confirm
        // validity of this
        *priority = new_priority;
    }
}

void Thread::SetPriority(s32 priority) {
    ClampPriority(this, &priority);

    // If thread was ready, adjust queues
    if (status == THREADSTATUS_READY)
        ready_queue.move(this, current_priority, priority);

    nominal_priority = current_priority = priority;
}

void Thread::BoostPriority(s32 priority) {
    ready_queue.move(this, current_priority, priority);
    current_priority = priority;
}

SharedPtr<Thread> SetupIdleThread() {
    // We need to pass a few valid values to get around parameter checking in Thread::Create.
    // TODO(yuriks): Figure out a way to avoid passing the bogus VAddr parameter
    auto thread = Thread::Create("idle", Memory::TLS_AREA_VADDR, THREADPRIO_LOWEST, 0,
            THREADPROCESSORID_0, 0).MoveFrom();

    thread->idle = true;
    return thread;
}

SharedPtr<Thread> SetupMainThread(u32 stack_size, u32 entry_point, s32 priority) {
    DEBUG_ASSERT(!GetCurrentThread());

    // Initialize new "main" thread
    auto thread_res = Thread::Create("main", entry_point, priority, 0,
            THREADPROCESSORID_0, Memory::HEAP_VADDR_END - stack_size);

    SharedPtr<Thread> thread = thread_res.MoveFrom();

    // Run new "main" thread
    SwitchContext(thread.get());

    return thread;
}

void Reschedule() {
    Thread* prev = GetCurrentThread();

    PriorityBoostStarvedThreads();

    Thread* next = PopNextReadyThread();
    HLE::g_reschedule = false;

    if (next != nullptr) {
        LOG_TRACE(Kernel, "context switch %u -> %u", prev->GetObjectId(), next->GetObjectId());
        SwitchContext(next);
    } else {
        LOG_TRACE(Kernel, "cannot context switch from %u, no higher priority thread!", prev->GetObjectId());

        for (auto& thread : thread_list) {
            LOG_TRACE(Kernel, "\tid=%u prio=0x%02X, status=0x%08X", thread->GetObjectId(), 
                      thread->current_priority, thread->status);
        }
    }
}

void Thread::SetWaitSynchronizationResult(ResultCode result) {
    context.cpu_registers[0] = result.raw;
}

void Thread::SetWaitSynchronizationOutput(s32 output) {
    context.cpu_registers[1] = output;
}

////////////////////////////////////////////////////////////////////////////////////////////////////

void ThreadingInit() {
    ThreadWakeupEventType = CoreTiming::RegisterEvent("ThreadWakeupCallback", ThreadWakeupCallback);

    current_thread = nullptr;
    next_thread_id = 1;

    thread_list.clear();
    ready_queue.clear();

    // Setup the idle thread
    SetupIdleThread();
}

void ThreadingShutdown() {
}

} // namespace