From e81a2080ebf9712231dd29c081141780ffd46cfb Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Fri, 20 Apr 2018 12:01:14 -0500
Subject: Kernel: Corrected the implementation of svcArbitrateLock and
 svcArbitrateUnlock.

Switch mutexes are no longer kernel objects, they are managed in userland and only use the kernel to handle the contention case.
Mutex addresses store a special flag value (0x40000000) to notify the guest code that there are still some threads waiting for the mutex to be released. This flag is updated when a thread calls ArbitrateUnlock.

TODO:
* Fix svcWaitProcessWideKey
* Fix svcSignalProcessWideKey
* Remove the Mutex class.
---
 src/core/hle/kernel/errors.h   |  1 +
 src/core/hle/kernel/mutex.cpp  | 94 ++++++++++++++++++++++++++++++++++++++++++
 src/core/hle/kernel/mutex.h    | 12 ++++++
 src/core/hle/kernel/svc.cpp    | 22 +---------
 src/core/hle/kernel/thread.cpp | 13 +++++-
 src/core/hle/kernel/thread.h   |  6 ++-
 6 files changed, 126 insertions(+), 22 deletions(-)

(limited to 'src/core')

diff --git a/src/core/hle/kernel/errors.h b/src/core/hle/kernel/errors.h
index 29d8dfdaa..5be20c878 100644
--- a/src/core/hle/kernel/errors.h
+++ b/src/core/hle/kernel/errors.h
@@ -20,6 +20,7 @@ enum {
     MaxConnectionsReached = 52,
 
     // Confirmed Switch OS error codes
+    MisalignedAddress = 102,
     InvalidHandle = 114,
     Timeout = 117,
     SynchronizationCanceled = 118,
diff --git a/src/core/hle/kernel/mutex.cpp b/src/core/hle/kernel/mutex.cpp
index 0b9dc700c..50a9a0805 100644
--- a/src/core/hle/kernel/mutex.cpp
+++ b/src/core/hle/kernel/mutex.cpp
@@ -7,6 +7,7 @@
 #include <boost/range/algorithm_ext/erase.hpp>
 #include "common/assert.h"
 #include "core/core.h"
+#include "core/hle/kernel/errors.h"
 #include "core/hle/kernel/handle_table.h"
 #include "core/hle/kernel/kernel.h"
 #include "core/hle/kernel/mutex.h"
@@ -15,6 +16,30 @@
 
 namespace Kernel {
 
+/// Returns the number of threads that are waiting for a mutex, and the highest priority one among
+/// those.
+static std::pair<SharedPtr<Thread>, u32> GetHighestPriorityMutexWaitingThread(VAddr mutex_addr) {
+    auto& thread_list = Core::System::GetInstance().Scheduler().GetThreadList();
+
+    SharedPtr<Thread> highest_priority_thread;
+    u32 num_waiters = 0;
+
+    for (auto& thread : thread_list) {
+        if (thread->mutex_wait_address != mutex_addr)
+            continue;
+
+        ASSERT(thread->status == THREADSTATUS_WAIT_MUTEX);
+
+        ++num_waiters;
+        if (highest_priority_thread == nullptr ||
+            thread->GetPriority() < highest_priority_thread->GetPriority()) {
+            highest_priority_thread = thread;
+        }
+    }
+
+    return {highest_priority_thread, num_waiters};
+}
+
 void ReleaseThreadMutexes(Thread* thread) {
     for (auto& mtx : thread->held_mutexes) {
         mtx->SetHasWaiters(false);
@@ -135,4 +160,73 @@ void Mutex::SetHasWaiters(bool has_waiters) {
     Memory::Write32(guest_addr, guest_state.raw);
 }
 
+ResultCode Mutex::TryAcquire(VAddr address, Handle holding_thread_handle,
+                             Handle requesting_thread_handle) {
+    // The mutex address must be 4-byte aligned
+    if ((address % sizeof(u32)) != 0) {
+        return ResultCode(ErrorModule::Kernel, ErrCodes::MisalignedAddress);
+    }
+
+    SharedPtr<Thread> holding_thread = g_handle_table.Get<Thread>(holding_thread_handle);
+    SharedPtr<Thread> requesting_thread = g_handle_table.Get<Thread>(requesting_thread_handle);
+
+    // TODO(Subv): It is currently unknown if it is possible to lock a mutex in behalf of another
+    // thread.
+    ASSERT(requesting_thread == GetCurrentThread());
+
+    u32 addr_value = Memory::Read32(address);
+
+    // If the mutex isn't being held, just return success.
+    if (addr_value != (holding_thread_handle | Mutex::MutexHasWaitersFlag)) {
+        return RESULT_SUCCESS;
+    }
+
+    if (holding_thread == nullptr)
+        return ERR_INVALID_HANDLE;
+
+    // Wait until the mutex is released
+    requesting_thread->mutex_wait_address = address;
+    requesting_thread->wait_handle = requesting_thread_handle;
+
+    requesting_thread->status = THREADSTATUS_WAIT_MUTEX;
+    requesting_thread->wakeup_callback = nullptr;
+
+    Core::System::GetInstance().PrepareReschedule();
+
+    return RESULT_SUCCESS;
+}
+
+ResultCode Mutex::Release(VAddr address) {
+    // The mutex address must be 4-byte aligned
+    if ((address % sizeof(u32)) != 0) {
+        return ResultCode(ErrorModule::Kernel, ErrCodes::MisalignedAddress);
+    }
+
+    auto [thread, num_waiters] = GetHighestPriorityMutexWaitingThread(address);
+
+    // There are no more threads waiting for the mutex, release it completely.
+    if (thread == nullptr) {
+        Memory::Write32(address, 0);
+        return RESULT_SUCCESS;
+    }
+
+    u32 mutex_value = thread->wait_handle;
+
+    if (num_waiters >= 2) {
+        // Notify the guest that there are still some threads waiting for the mutex
+        mutex_value |= Mutex::MutexHasWaitersFlag;
+    }
+
+    // Grant the mutex to the next waiting thread and resume it.
+    Memory::Write32(address, mutex_value);
+
+    ASSERT(thread->status == THREADSTATUS_WAIT_MUTEX);
+    thread->ResumeFromWait();
+
+    thread->condvar_wait_address = 0;
+    thread->mutex_wait_address = 0;
+    thread->wait_handle = 0;
+
+    return RESULT_SUCCESS;
+}
 } // namespace Kernel
diff --git a/src/core/hle/kernel/mutex.h b/src/core/hle/kernel/mutex.h
index 38db21005..310923087 100644
--- a/src/core/hle/kernel/mutex.h
+++ b/src/core/hle/kernel/mutex.h
@@ -77,6 +77,18 @@ public:
     /// Sets the has_waiters bit in the guest state.
     void SetHasWaiters(bool has_waiters);
 
+    /// Flag that indicates that a mutex still has threads waiting for it.
+    static constexpr u32 MutexHasWaitersFlag = 0x40000000;
+    /// Mask of the bits in a mutex address value that contain the mutex owner.
+    static constexpr u32 MutexOwnerMask = 0xBFFFFFFF;
+
+    /// Attempts to acquire a mutex at the specified address.
+    static ResultCode TryAcquire(VAddr address, Handle holding_thread_handle,
+                                 Handle requesting_thread_handle);
+
+    /// Releases the mutex at the specified address.
+    static ResultCode Release(VAddr address);
+
 private:
     Mutex();
     ~Mutex() override;
diff --git a/src/core/hle/kernel/svc.cpp b/src/core/hle/kernel/svc.cpp
index 6204bcaaa..92273b488 100644
--- a/src/core/hle/kernel/svc.cpp
+++ b/src/core/hle/kernel/svc.cpp
@@ -262,32 +262,14 @@ static ResultCode ArbitrateLock(Handle holding_thread_handle, VAddr mutex_addr,
               "requesting_current_thread_handle=0x%08X",
               holding_thread_handle, mutex_addr, requesting_thread_handle);
 
-    SharedPtr<Thread> holding_thread = g_handle_table.Get<Thread>(holding_thread_handle);
-    SharedPtr<Thread> requesting_thread = g_handle_table.Get<Thread>(requesting_thread_handle);
-
-    ASSERT(requesting_thread);
-    ASSERT(requesting_thread == GetCurrentThread());
-
-    SharedPtr<Mutex> mutex = g_object_address_table.Get<Mutex>(mutex_addr);
-    if (!mutex) {
-        // Create a new mutex for the specified address if one does not already exist
-        mutex = Mutex::Create(holding_thread, mutex_addr);
-        mutex->name = Common::StringFromFormat("mutex-%llx", mutex_addr);
-    }
-
-    ASSERT(holding_thread == mutex->GetHoldingThread());
-
-    return WaitSynchronization1(mutex, requesting_thread.get());
+    return Mutex::TryAcquire(mutex_addr, holding_thread_handle, requesting_thread_handle);
 }
 
 /// Unlock a mutex
 static ResultCode ArbitrateUnlock(VAddr mutex_addr) {
     LOG_TRACE(Kernel_SVC, "called mutex_addr=0x%llx", mutex_addr);
 
-    SharedPtr<Mutex> mutex = g_object_address_table.Get<Mutex>(mutex_addr);
-    ASSERT(mutex);
-
-    return mutex->Release(GetCurrentThread());
+    return Mutex::Release(mutex_addr);
 }
 
 /// Break program execution
diff --git a/src/core/hle/kernel/thread.cpp b/src/core/hle/kernel/thread.cpp
index f3a8aa4aa..0a0ad7cfb 100644
--- a/src/core/hle/kernel/thread.cpp
+++ b/src/core/hle/kernel/thread.cpp
@@ -126,6 +126,14 @@ static void ThreadWakeupCallback(u64 thread_handle, int cycles_late) {
             resume = thread->wakeup_callback(ThreadWakeupReason::Timeout, thread, nullptr, 0);
     }
 
+    if (thread->mutex_wait_address != 0 || thread->condvar_wait_address != 0 ||
+        thread->wait_handle) {
+        ASSERT(thread->status == THREADSTATUS_WAIT_MUTEX);
+        thread->mutex_wait_address = 0;
+        thread->condvar_wait_address = 0;
+        thread->wait_handle = 0;
+    }
+
     if (resume)
         thread->ResumeFromWait();
 }
@@ -151,6 +159,7 @@ void Thread::ResumeFromWait() {
     case THREADSTATUS_WAIT_HLE_EVENT:
     case THREADSTATUS_WAIT_SLEEP:
     case THREADSTATUS_WAIT_IPC:
+    case THREADSTATUS_WAIT_MUTEX:
         break;
 
     case THREADSTATUS_READY:
@@ -256,7 +265,9 @@ ResultVal<SharedPtr<Thread>> Thread::Create(std::string name, VAddr entry_point,
     thread->last_running_ticks = CoreTiming::GetTicks();
     thread->processor_id = processor_id;
     thread->wait_objects.clear();
-    thread->wait_address = 0;
+    thread->mutex_wait_address = 0;
+    thread->condvar_wait_address = 0;
+    thread->wait_handle = 0;
     thread->name = std::move(name);
     thread->callback_handle = wakeup_callback_handle_table.Create(thread).Unwrap();
     thread->owner_process = owner_process;
diff --git a/src/core/hle/kernel/thread.h b/src/core/hle/kernel/thread.h
index dbf47e269..a3a6e6a64 100644
--- a/src/core/hle/kernel/thread.h
+++ b/src/core/hle/kernel/thread.h
@@ -43,6 +43,7 @@ enum ThreadStatus {
     THREADSTATUS_WAIT_IPC,       ///< Waiting for the reply from an IPC request
     THREADSTATUS_WAIT_SYNCH_ANY, ///< Waiting due to WaitSynch1 or WaitSynchN with wait_all = false
     THREADSTATUS_WAIT_SYNCH_ALL, ///< Waiting due to WaitSynchronizationN with wait_all = true
+    THREADSTATUS_WAIT_MUTEX,     ///< Waiting due to an ArbitrateLock/WaitProcessWideKey svc
     THREADSTATUS_DORMANT,        ///< Created but not yet made ready
     THREADSTATUS_DEAD            ///< Run to completion, or forcefully terminated
 };
@@ -217,7 +218,10 @@ public:
     // passed to WaitSynchronization1/N.
     std::vector<SharedPtr<WaitObject>> wait_objects;
 
-    VAddr wait_address; ///< If waiting on an AddressArbiter, this is the arbitration address
+    // If waiting on a ConditionVariable, this is the ConditionVariable  address
+    VAddr condvar_wait_address;
+    VAddr mutex_wait_address; ///< If waiting on a Mutex, this is the mutex address
+    Handle wait_handle;       ///< The handle used to wait for the mutex.
 
     std::string name;
 
-- 
cgit v1.2.3


From b18ccf9399430a91790a93a122d5cd05266301ab Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Fri, 20 Apr 2018 14:39:28 -0500
Subject: Kernel: Properly implemented svcWaitProcessWideKey and
 svcSignalProcessWideKey

They work in tandem with guest code to provide synchronization primitives along with svcArbitrateLock/Unlock
---
 src/core/hle/kernel/svc.cpp | 129 ++++++++++++++++----------------------------
 1 file changed, 46 insertions(+), 83 deletions(-)

(limited to 'src/core')

diff --git a/src/core/hle/kernel/svc.cpp b/src/core/hle/kernel/svc.cpp
index 92273b488..99c1c2d2a 100644
--- a/src/core/hle/kernel/svc.cpp
+++ b/src/core/hle/kernel/svc.cpp
@@ -616,77 +616,18 @@ static ResultCode WaitProcessWideKeyAtomic(VAddr mutex_addr, VAddr condition_var
     SharedPtr<Thread> thread = g_handle_table.Get<Thread>(thread_handle);
     ASSERT(thread);
 
-    SharedPtr<Mutex> mutex = g_object_address_table.Get<Mutex>(mutex_addr);
-    if (!mutex) {
-        // Create a new mutex for the specified address if one does not already exist
-        mutex = Mutex::Create(thread, mutex_addr);
-        mutex->name = Common::StringFromFormat("mutex-%llx", mutex_addr);
-    }
-
-    SharedPtr<ConditionVariable> condition_variable =
-        g_object_address_table.Get<ConditionVariable>(condition_variable_addr);
-    if (!condition_variable) {
-        // Create a new condition_variable for the specified address if one does not already exist
-        condition_variable = ConditionVariable::Create(condition_variable_addr).Unwrap();
-        condition_variable->name =
-            Common::StringFromFormat("condition-variable-%llx", condition_variable_addr);
-    }
-
-    if (condition_variable->mutex_addr) {
-        // Previously created the ConditionVariable using WaitProcessWideKeyAtomic, verify
-        // everything is correct
-        ASSERT(condition_variable->mutex_addr == mutex_addr);
-    } else {
-        // Previously created the ConditionVariable using SignalProcessWideKey, set the mutex
-        // associated with it
-        condition_variable->mutex_addr = mutex_addr;
-    }
-
-    if (mutex->GetOwnerHandle()) {
-        // Release the mutex if the current thread is holding it
-        mutex->Release(thread.get());
-    }
-
-    auto wakeup_callback = [mutex, nano_seconds](ThreadWakeupReason reason,
-                                                 SharedPtr<Thread> thread,
-                                                 SharedPtr<WaitObject> object, size_t index) {
-        ASSERT(thread->status == THREADSTATUS_WAIT_SYNCH_ANY);
-
-        if (reason == ThreadWakeupReason::Timeout) {
-            thread->SetWaitSynchronizationResult(RESULT_TIMEOUT);
-            return true;
-        }
-
-        ASSERT(reason == ThreadWakeupReason::Signal);
-
-        // Now try to acquire the mutex and don't resume if it's not available.
-        if (!mutex->ShouldWait(thread.get())) {
-            mutex->Acquire(thread.get());
-            thread->SetWaitSynchronizationResult(RESULT_SUCCESS);
-            return true;
-        }
-
-        if (nano_seconds == 0) {
-            thread->SetWaitSynchronizationResult(RESULT_TIMEOUT);
-            return true;
-        }
-
-        thread->wait_objects = {mutex};
-        mutex->AddWaitingThread(thread);
-        thread->status = THREADSTATUS_WAIT_SYNCH_ANY;
-
-        // Create an event to wake the thread up after the
-        // specified nanosecond delay has passed
-        thread->WakeAfterDelay(nano_seconds);
-        thread->wakeup_callback = DefaultThreadWakeupCallback;
+    CASCADE_CODE(Mutex::Release(mutex_addr));
 
-        Core::System::GetInstance().PrepareReschedule();
+    SharedPtr<Thread> current_thread = GetCurrentThread();
+    current_thread->condvar_wait_address = condition_variable_addr;
+    current_thread->mutex_wait_address = mutex_addr;
+    current_thread->wait_handle = thread_handle;
+    current_thread->status = THREADSTATUS_WAIT_MUTEX;
+    current_thread->wakeup_callback = nullptr;
 
-        return false;
-    };
-    CASCADE_CODE(
-        WaitSynchronization1(condition_variable, thread.get(), nano_seconds, wakeup_callback));
+    current_thread->WakeAfterDelay(nano_seconds);
 
+    Core::System::GetInstance().PrepareReschedule();
     return RESULT_SUCCESS;
 }
 
@@ -695,24 +636,46 @@ static ResultCode SignalProcessWideKey(VAddr condition_variable_addr, s32 target
     LOG_TRACE(Kernel_SVC, "called, condition_variable_addr=0x%llx, target=0x%08x",
               condition_variable_addr, target);
 
-    // Wakeup all or one thread - Any other value is unimplemented
-    ASSERT(target == -1 || target == 1);
+    u32 processed = 0;
+    auto& thread_list = Core::System::GetInstance().Scheduler().GetThreadList();
+
+    for (auto& thread : thread_list) {
+        if (thread->condvar_wait_address != condition_variable_addr)
+            continue;
 
-    SharedPtr<ConditionVariable> condition_variable =
-        g_object_address_table.Get<ConditionVariable>(condition_variable_addr);
-    if (!condition_variable) {
-        // Create a new condition_variable for the specified address if one does not already exist
-        condition_variable = ConditionVariable::Create(condition_variable_addr).Unwrap();
-        condition_variable->name =
-            Common::StringFromFormat("condition-variable-%llx", condition_variable_addr);
-    }
+        // Only process up to 'target' threads, unless 'target' is -1, in which case process
+        // them all.
+        if (target != -1 && processed >= target)
+            break;
 
-    CASCADE_CODE(condition_variable->Release(target));
+        // If the mutex is not yet acquired, acquire it.
+        u32 mutex_val = Memory::Read32(thread->mutex_wait_address);
+
+        if (mutex_val == 0) {
+            // We were able to acquire the mutex, resume this thread.
+            Memory::Write32(thread->mutex_wait_address, thread->wait_handle);
+            ASSERT(thread->status == THREADSTATUS_WAIT_MUTEX);
+            thread->ResumeFromWait();
+
+            thread->mutex_wait_address = 0;
+            thread->condvar_wait_address = 0;
+            thread->wait_handle = 0;
+        } else {
+            // Couldn't acquire the mutex, block the thread.
+            Handle owner_handle = static_cast<Handle>(mutex_val & Mutex::MutexOwnerMask);
+            auto owner = g_handle_table.Get<Thread>(owner_handle);
+            ASSERT(owner);
+            ASSERT(thread->status != THREADSTATUS_RUNNING);
+            thread->status = THREADSTATUS_WAIT_MUTEX;
+            thread->wakeup_callback = nullptr;
+
+            // Signal that the mutex now has a waiting thread.
+            Memory::Write32(thread->mutex_wait_address, mutex_val | Mutex::MutexHasWaitersFlag);
+
+            Core::System::GetInstance().PrepareReschedule();
+        }
 
-    if (condition_variable->mutex_addr) {
-        // If a mutex was created for this condition_variable, wait the current thread on it
-        SharedPtr<Mutex> mutex = g_object_address_table.Get<Mutex>(condition_variable->mutex_addr);
-        return WaitSynchronization1(mutex, GetCurrentThread());
+        ++processed;
     }
 
     return RESULT_SUCCESS;
-- 
cgit v1.2.3


From 5fdfbfe25adafd2734a19fe94cccc58993cb12e7 Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Fri, 20 Apr 2018 14:42:29 -0500
Subject: Kernel: Remove old and unused Mutex code.

---
 src/core/hle/kernel/mutex.cpp  | 120 -----------------------------------------
 src/core/hle/kernel/mutex.h    |  82 ++--------------------------
 src/core/hle/kernel/thread.cpp |   3 --
 src/core/hle/kernel/thread.h   |   7 ---
 4 files changed, 3 insertions(+), 209 deletions(-)

(limited to 'src/core')

diff --git a/src/core/hle/kernel/mutex.cpp b/src/core/hle/kernel/mutex.cpp
index 50a9a0805..5cc0bd266 100644
--- a/src/core/hle/kernel/mutex.cpp
+++ b/src/core/hle/kernel/mutex.cpp
@@ -40,126 +40,6 @@ static std::pair<SharedPtr<Thread>, u32> GetHighestPriorityMutexWaitingThread(VA
     return {highest_priority_thread, num_waiters};
 }
 
-void ReleaseThreadMutexes(Thread* thread) {
-    for (auto& mtx : thread->held_mutexes) {
-        mtx->SetHasWaiters(false);
-        mtx->SetHoldingThread(nullptr);
-        mtx->WakeupAllWaitingThreads();
-    }
-    thread->held_mutexes.clear();
-}
-
-Mutex::Mutex() {}
-Mutex::~Mutex() {}
-
-SharedPtr<Mutex> Mutex::Create(SharedPtr<Kernel::Thread> holding_thread, VAddr guest_addr,
-                               std::string name) {
-    SharedPtr<Mutex> mutex(new Mutex);
-
-    mutex->guest_addr = guest_addr;
-    mutex->name = std::move(name);
-
-    // If mutex was initialized with a holding thread, acquire it by the holding thread
-    if (holding_thread) {
-        mutex->Acquire(holding_thread.get());
-    }
-
-    // Mutexes are referenced by guest address, so track this in the kernel
-    g_object_address_table.Insert(guest_addr, mutex);
-
-    return mutex;
-}
-
-bool Mutex::ShouldWait(Thread* thread) const {
-    auto holding_thread = GetHoldingThread();
-    return holding_thread != nullptr && thread != holding_thread;
-}
-
-void Mutex::Acquire(Thread* thread) {
-    ASSERT_MSG(!ShouldWait(thread), "object unavailable!");
-
-    priority = thread->current_priority;
-    thread->held_mutexes.insert(this);
-    SetHoldingThread(thread);
-    thread->UpdatePriority();
-    Core::System::GetInstance().PrepareReschedule();
-}
-
-ResultCode Mutex::Release(Thread* thread) {
-    auto holding_thread = GetHoldingThread();
-    ASSERT(holding_thread);
-
-    // We can only release the mutex if it's held by the calling thread.
-    ASSERT(thread == holding_thread);
-
-    holding_thread->held_mutexes.erase(this);
-    holding_thread->UpdatePriority();
-    SetHoldingThread(nullptr);
-    SetHasWaiters(!GetWaitingThreads().empty());
-    WakeupAllWaitingThreads();
-    Core::System::GetInstance().PrepareReschedule();
-
-    return RESULT_SUCCESS;
-}
-
-void Mutex::AddWaitingThread(SharedPtr<Thread> thread) {
-    WaitObject::AddWaitingThread(thread);
-    thread->pending_mutexes.insert(this);
-    SetHasWaiters(true);
-    UpdatePriority();
-}
-
-void Mutex::RemoveWaitingThread(Thread* thread) {
-    WaitObject::RemoveWaitingThread(thread);
-    thread->pending_mutexes.erase(this);
-    if (!GetHasWaiters())
-        SetHasWaiters(!GetWaitingThreads().empty());
-    UpdatePriority();
-}
-
-void Mutex::UpdatePriority() {
-    if (!GetHoldingThread())
-        return;
-
-    u32 best_priority = THREADPRIO_LOWEST;
-    for (auto& waiter : GetWaitingThreads()) {
-        if (waiter->current_priority < best_priority)
-            best_priority = waiter->current_priority;
-    }
-
-    if (best_priority != priority) {
-        priority = best_priority;
-        GetHoldingThread()->UpdatePriority();
-    }
-}
-
-Handle Mutex::GetOwnerHandle() const {
-    GuestState guest_state{Memory::Read32(guest_addr)};
-    return guest_state.holding_thread_handle;
-}
-
-SharedPtr<Thread> Mutex::GetHoldingThread() const {
-    GuestState guest_state{Memory::Read32(guest_addr)};
-    return g_handle_table.Get<Thread>(guest_state.holding_thread_handle);
-}
-
-void Mutex::SetHoldingThread(SharedPtr<Thread> thread) {
-    GuestState guest_state{Memory::Read32(guest_addr)};
-    guest_state.holding_thread_handle.Assign(thread ? thread->guest_handle : 0);
-    Memory::Write32(guest_addr, guest_state.raw);
-}
-
-bool Mutex::GetHasWaiters() const {
-    GuestState guest_state{Memory::Read32(guest_addr)};
-    return guest_state.has_waiters != 0;
-}
-
-void Mutex::SetHasWaiters(bool has_waiters) {
-    GuestState guest_state{Memory::Read32(guest_addr)};
-    guest_state.has_waiters.Assign(has_waiters ? 1 : 0);
-    Memory::Write32(guest_addr, guest_state.raw);
-}
-
 ResultCode Mutex::TryAcquire(VAddr address, Handle holding_thread_handle,
                              Handle requesting_thread_handle) {
     // The mutex address must be 4-byte aligned
diff --git a/src/core/hle/kernel/mutex.h b/src/core/hle/kernel/mutex.h
index 310923087..3117e7c70 100644
--- a/src/core/hle/kernel/mutex.h
+++ b/src/core/hle/kernel/mutex.h
@@ -15,68 +15,8 @@ namespace Kernel {
 
 class Thread;
 
-class Mutex final : public WaitObject {
+class Mutex final {
 public:
-    /**
-     * Creates a mutex.
-     * @param holding_thread Specifies a thread already holding the mutex. If not nullptr, this
-     * thread will acquire the mutex.
-     * @param guest_addr Address of the object tracking the mutex in guest memory. If specified,
-     * this mutex will update the guest object when its state changes.
-     * @param name Optional name of mutex
-     * @return Pointer to new Mutex object
-     */
-    static SharedPtr<Mutex> Create(SharedPtr<Kernel::Thread> holding_thread, VAddr guest_addr = 0,
-                                   std::string name = "Unknown");
-
-    std::string GetTypeName() const override {
-        return "Mutex";
-    }
-    std::string GetName() const override {
-        return name;
-    }
-
-    static const HandleType HANDLE_TYPE = HandleType::Mutex;
-    HandleType GetHandleType() const override {
-        return HANDLE_TYPE;
-    }
-
-    u32 priority;     ///< The priority of the mutex, used for priority inheritance.
-    std::string name; ///< Name of mutex (optional)
-    VAddr guest_addr; ///< Address of the guest mutex value
-
-    /**
-     * Elevate the mutex priority to the best priority
-     * among the priorities of all its waiting threads.
-     */
-    void UpdatePriority();
-
-    bool ShouldWait(Thread* thread) const override;
-    void Acquire(Thread* thread) override;
-
-    void AddWaitingThread(SharedPtr<Thread> thread) override;
-    void RemoveWaitingThread(Thread* thread) override;
-
-    /**
-     * Attempts to release the mutex from the specified thread.
-     * @param thread Thread that wants to release the mutex.
-     * @returns The result code of the operation.
-     */
-    ResultCode Release(Thread* thread);
-
-    /// Gets the handle to the holding process stored in the guest state.
-    Handle GetOwnerHandle() const;
-
-    /// Gets the Thread pointed to by the owner handle
-    SharedPtr<Thread> GetHoldingThread() const;
-    /// Sets the holding process handle in the guest state.
-    void SetHoldingThread(SharedPtr<Thread> thread);
-
-    /// Returns the has_waiters bit in the guest state.
-    bool GetHasWaiters() const;
-    /// Sets the has_waiters bit in the guest state.
-    void SetHasWaiters(bool has_waiters);
-
     /// Flag that indicates that a mutex still has threads waiting for it.
     static constexpr u32 MutexHasWaitersFlag = 0x40000000;
     /// Mask of the bits in a mutex address value that contain the mutex owner.
@@ -90,24 +30,8 @@ public:
     static ResultCode Release(VAddr address);
 
 private:
-    Mutex();
-    ~Mutex() override;
-
-    /// Object in guest memory used to track the mutex state
-    union GuestState {
-        u32_le raw;
-        /// Handle of the thread that currently holds the mutex, 0 if available
-        BitField<0, 30, u32_le> holding_thread_handle;
-        /// 1 when there are threads waiting for this mutex, otherwise 0
-        BitField<30, 1, u32_le> has_waiters;
-    };
-    static_assert(sizeof(GuestState) == 4, "GuestState size is incorrect");
+    Mutex() = default;
+    ~Mutex() = default;
 };
 
-/**
- * Releases all the mutexes held by the specified thread
- * @param thread Thread that is holding the mutexes
- */
-void ReleaseThreadMutexes(Thread* thread);
-
 } // namespace Kernel
diff --git a/src/core/hle/kernel/thread.cpp b/src/core/hle/kernel/thread.cpp
index 0a0ad7cfb..8093c4496 100644
--- a/src/core/hle/kernel/thread.cpp
+++ b/src/core/hle/kernel/thread.cpp
@@ -77,9 +77,6 @@ void Thread::Stop() {
     }
     wait_objects.clear();
 
-    // Release all the mutexes that this thread holds
-    ReleaseThreadMutexes(this);
-
     // Mark the TLS slot in the thread's page as free.
     u64 tls_page = (tls_address - Memory::TLS_AREA_VADDR) / Memory::PAGE_SIZE;
     u64 tls_slot =
diff --git a/src/core/hle/kernel/thread.h b/src/core/hle/kernel/thread.h
index a3a6e6a64..74d5904b8 100644
--- a/src/core/hle/kernel/thread.h
+++ b/src/core/hle/kernel/thread.h
@@ -55,7 +55,6 @@ enum class ThreadWakeupReason {
 
 namespace Kernel {
 
-class Mutex;
 class Process;
 
 class Thread final : public WaitObject {
@@ -206,12 +205,6 @@ public:
 
     VAddr tls_address; ///< Virtual address of the Thread Local Storage of the thread
 
-    /// Mutexes currently held by this thread, which will be released when it exits.
-    boost::container::flat_set<SharedPtr<Mutex>> held_mutexes;
-
-    /// Mutexes that this thread is currently waiting for.
-    boost::container::flat_set<SharedPtr<Mutex>> pending_mutexes;
-
     SharedPtr<Process> owner_process; ///< Process that owns this thread
 
     /// Objects that the thread is waiting on, in the same order as they were
-- 
cgit v1.2.3


From be155f4d9d410886853c25ffa032ce41a7428337 Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Fri, 20 Apr 2018 14:45:52 -0500
Subject: Kernel: Remove unused ConditionVariable class.

---
 src/core/CMakeLists.txt                    |  2 -
 src/core/hle/kernel/condition_variable.cpp | 64 ------------------------------
 src/core/hle/kernel/condition_variable.h   | 63 -----------------------------
 src/core/hle/kernel/svc.cpp                |  6 ---
 src/core/hle/kernel/thread.cpp             |  9 -----
 src/core/hle/kernel/thread.h               |  6 ---
 6 files changed, 150 deletions(-)
 delete mode 100644 src/core/hle/kernel/condition_variable.cpp
 delete mode 100644 src/core/hle/kernel/condition_variable.h

(limited to 'src/core')

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index c1a645460..b3807c204 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -42,8 +42,6 @@ add_library(core STATIC
     hle/kernel/client_port.h
     hle/kernel/client_session.cpp
     hle/kernel/client_session.h
-    hle/kernel/condition_variable.cpp
-    hle/kernel/condition_variable.h
     hle/kernel/errors.h
     hle/kernel/event.cpp
     hle/kernel/event.h
diff --git a/src/core/hle/kernel/condition_variable.cpp b/src/core/hle/kernel/condition_variable.cpp
deleted file mode 100644
index a786d7f74..000000000
--- a/src/core/hle/kernel/condition_variable.cpp
+++ /dev/null
@@ -1,64 +0,0 @@
-// Copyright 2018 yuzu emulator team
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#include "common/assert.h"
-#include "core/hle/kernel/condition_variable.h"
-#include "core/hle/kernel/errors.h"
-#include "core/hle/kernel/kernel.h"
-#include "core/hle/kernel/object_address_table.h"
-#include "core/hle/kernel/thread.h"
-
-namespace Kernel {
-
-ConditionVariable::ConditionVariable() {}
-ConditionVariable::~ConditionVariable() {}
-
-ResultVal<SharedPtr<ConditionVariable>> ConditionVariable::Create(VAddr guest_addr,
-                                                                  std::string name) {
-    SharedPtr<ConditionVariable> condition_variable(new ConditionVariable);
-
-    condition_variable->name = std::move(name);
-    condition_variable->guest_addr = guest_addr;
-    condition_variable->mutex_addr = 0;
-
-    // Condition variables are referenced by guest address, so track this in the kernel
-    g_object_address_table.Insert(guest_addr, condition_variable);
-
-    return MakeResult<SharedPtr<ConditionVariable>>(std::move(condition_variable));
-}
-
-bool ConditionVariable::ShouldWait(Thread* thread) const {
-    return GetAvailableCount() <= 0;
-}
-
-void ConditionVariable::Acquire(Thread* thread) {
-    if (GetAvailableCount() <= 0)
-        return;
-
-    SetAvailableCount(GetAvailableCount() - 1);
-}
-
-ResultCode ConditionVariable::Release(s32 target) {
-    if (target == -1) {
-        // When -1, wake up all waiting threads
-        SetAvailableCount(static_cast<s32>(GetWaitingThreads().size()));
-        WakeupAllWaitingThreads();
-    } else {
-        // Otherwise, wake up just a single thread
-        SetAvailableCount(target);
-        WakeupWaitingThread(GetHighestPriorityReadyThread());
-    }
-
-    return RESULT_SUCCESS;
-}
-
-s32 ConditionVariable::GetAvailableCount() const {
-    return Memory::Read32(guest_addr);
-}
-
-void ConditionVariable::SetAvailableCount(s32 value) const {
-    Memory::Write32(guest_addr, value);
-}
-
-} // namespace Kernel
diff --git a/src/core/hle/kernel/condition_variable.h b/src/core/hle/kernel/condition_variable.h
deleted file mode 100644
index 1c9f06769..000000000
--- a/src/core/hle/kernel/condition_variable.h
+++ /dev/null
@@ -1,63 +0,0 @@
-// Copyright 2018 yuzu emulator team
-// Licensed under GPLv2 or any later version
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include <string>
-#include <queue>
-#include "common/common_types.h"
-#include "core/hle/kernel/kernel.h"
-#include "core/hle/kernel/wait_object.h"
-#include "core/hle/result.h"
-
-namespace Kernel {
-
-class ConditionVariable final : public WaitObject {
-public:
-    /**
-     * Creates a condition variable.
-     * @param guest_addr Address of the object tracking the condition variable in guest memory. If
-     * specified, this condition variable will update the guest object when its state changes.
-     * @param name Optional name of condition variable.
-     * @return The created condition variable.
-     */
-    static ResultVal<SharedPtr<ConditionVariable>> Create(VAddr guest_addr,
-                                                          std::string name = "Unknown");
-
-    std::string GetTypeName() const override {
-        return "ConditionVariable";
-    }
-    std::string GetName() const override {
-        return name;
-    }
-
-    static const HandleType HANDLE_TYPE = HandleType::ConditionVariable;
-    HandleType GetHandleType() const override {
-        return HANDLE_TYPE;
-    }
-
-    s32 GetAvailableCount() const;
-    void SetAvailableCount(s32 value) const;
-
-    std::string name; ///< Name of condition variable (optional)
-    VAddr guest_addr; ///< Address of the guest condition variable value
-    VAddr mutex_addr; ///< (optional) Address of guest mutex value associated with this condition
-                      ///< variable, used for implementing events
-
-    bool ShouldWait(Thread* thread) const override;
-    void Acquire(Thread* thread) override;
-
-    /**
-     * Releases a slot from a condition variable.
-     * @param target The number of threads to wakeup, -1 is all.
-     * @return ResultCode indicating if the operation succeeded.
-     */
-    ResultCode Release(s32 target);
-
-private:
-    ConditionVariable();
-    ~ConditionVariable() override;
-};
-
-} // namespace Kernel
diff --git a/src/core/hle/kernel/svc.cpp b/src/core/hle/kernel/svc.cpp
index 99c1c2d2a..082c36caf 100644
--- a/src/core/hle/kernel/svc.cpp
+++ b/src/core/hle/kernel/svc.cpp
@@ -13,7 +13,6 @@
 #include "core/core_timing.h"
 #include "core/hle/kernel/client_port.h"
 #include "core/hle/kernel/client_session.h"
-#include "core/hle/kernel/condition_variable.h"
 #include "core/hle/kernel/event.h"
 #include "core/hle/kernel/handle_table.h"
 #include "core/hle/kernel/mutex.h"
@@ -394,11 +393,6 @@ static ResultCode SetThreadPriority(Handle handle, u32 priority) {
     }
 
     thread->SetPriority(priority);
-    thread->UpdatePriority();
-
-    // Update the mutexes that this thread is waiting for
-    for (auto& mutex : thread->pending_mutexes)
-        mutex->UpdatePriority();
 
     Core::System::GetInstance().PrepareReschedule();
     return RESULT_SUCCESS;
diff --git a/src/core/hle/kernel/thread.cpp b/src/core/hle/kernel/thread.cpp
index 8093c4496..16d9b9e36 100644
--- a/src/core/hle/kernel/thread.cpp
+++ b/src/core/hle/kernel/thread.cpp
@@ -329,15 +329,6 @@ void Thread::SetPriority(u32 priority) {
     nominal_priority = current_priority = priority;
 }
 
-void Thread::UpdatePriority() {
-    u32 best_priority = nominal_priority;
-    for (auto& mutex : held_mutexes) {
-        if (mutex->priority < best_priority)
-            best_priority = mutex->priority;
-    }
-    BoostPriority(best_priority);
-}
-
 void Thread::BoostPriority(u32 priority) {
     Core::System::GetInstance().Scheduler().SetThreadPriority(this, priority);
     current_priority = priority;
diff --git a/src/core/hle/kernel/thread.h b/src/core/hle/kernel/thread.h
index 74d5904b8..ee13d20f1 100644
--- a/src/core/hle/kernel/thread.h
+++ b/src/core/hle/kernel/thread.h
@@ -103,12 +103,6 @@ public:
      */
     void SetPriority(u32 priority);
 
-    /**
-     * Boost's a thread's priority to the best priority among the thread's held mutexes.
-     * This prevents priority inversion via priority inheritance.
-     */
-    void UpdatePriority();
-
     /**
      * Temporarily boosts the thread's priority until the next time it is scheduled
      * @param priority The new priority
-- 
cgit v1.2.3


From 013778aa21bad3769b739d14843b8ef2bb3185c9 Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Fri, 20 Apr 2018 15:52:06 -0500
Subject: Qt: Update the WaitTree widget to show info about the current mutex
 of each thread.

---
 src/core/hle/kernel/kernel.h                    | 4 ----
 src/core/hle/service/nvflinger/buffer_queue.cpp | 6 ++++--
 src/core/hle/service/nvflinger/buffer_queue.h   | 6 ++++--
 3 files changed, 8 insertions(+), 8 deletions(-)

(limited to 'src/core')

diff --git a/src/core/hle/kernel/kernel.h b/src/core/hle/kernel/kernel.h
index 053bf4e17..402ae900f 100644
--- a/src/core/hle/kernel/kernel.h
+++ b/src/core/hle/kernel/kernel.h
@@ -18,12 +18,10 @@ using Handle = u32;
 enum class HandleType : u32 {
     Unknown,
     Event,
-    Mutex,
     SharedMemory,
     Thread,
     Process,
     AddressArbiter,
-    ConditionVariable,
     Timer,
     ResourceLimit,
     CodeSet,
@@ -63,9 +61,7 @@ public:
     bool IsWaitable() const {
         switch (GetHandleType()) {
         case HandleType::Event:
-        case HandleType::Mutex:
         case HandleType::Thread:
-        case HandleType::ConditionVariable:
         case HandleType::Timer:
         case HandleType::ServerPort:
         case HandleType::ServerSession:
diff --git a/src/core/hle/service/nvflinger/buffer_queue.cpp b/src/core/hle/service/nvflinger/buffer_queue.cpp
index 03a4fed59..e4ff2e267 100644
--- a/src/core/hle/service/nvflinger/buffer_queue.cpp
+++ b/src/core/hle/service/nvflinger/buffer_queue.cpp
@@ -9,7 +9,8 @@
 #include "core/core_timing.h"
 #include "core/hle/service/nvflinger/buffer_queue.h"
 
-namespace Service::NVFlinger {
+namespace Service {
+namespace NVFlinger {
 
 BufferQueue::BufferQueue(u32 id, u64 layer_id) : id(id), layer_id(layer_id) {
     native_handle = Kernel::Event::Create(Kernel::ResetType::OneShot, "BufferQueue NativeHandle");
@@ -110,4 +111,5 @@ void BufferQueue::SetBufferWaitEvent(Kernel::SharedPtr<Kernel::Event>&& wait_eve
     buffer_wait_event = std::move(wait_event);
 }
 
-} // namespace Service::NVFlinger
+} // namespace NVFlinger
+} // namespace Service
diff --git a/src/core/hle/service/nvflinger/buffer_queue.h b/src/core/hle/service/nvflinger/buffer_queue.h
index 95adc4706..1de5767cb 100644
--- a/src/core/hle/service/nvflinger/buffer_queue.h
+++ b/src/core/hle/service/nvflinger/buffer_queue.h
@@ -13,7 +13,8 @@ namespace CoreTiming {
 struct EventType;
 }
 
-namespace Service::NVFlinger {
+namespace Service {
+namespace NVFlinger {
 
 struct IGBPBuffer {
     u32_le magic;
@@ -97,4 +98,5 @@ private:
     Kernel::SharedPtr<Kernel::Event> buffer_wait_event;
 };
 
-} // namespace Service::NVFlinger
+} // namespace NVFlinger
+} // namespace Service
-- 
cgit v1.2.3


From a70ed9c8ae034a1035d1b099161ad740840c5a94 Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Fri, 20 Apr 2018 17:41:11 -0500
Subject: Kernel: Use 0x2C as default main thread priority for homebrew and
 lone NRO/NSOs

---
 src/core/hle/kernel/thread.h | 2 +-
 src/core/loader/nro.cpp      | 2 +-
 src/core/loader/nso.cpp      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

(limited to 'src/core')

diff --git a/src/core/hle/kernel/thread.h b/src/core/hle/kernel/thread.h
index ee13d20f1..0e0eae28d 100644
--- a/src/core/hle/kernel/thread.h
+++ b/src/core/hle/kernel/thread.h
@@ -18,7 +18,7 @@
 enum ThreadPriority : u32 {
     THREADPRIO_HIGHEST = 0,       ///< Highest thread priority
     THREADPRIO_USERLAND_MAX = 24, ///< Highest thread priority for userland apps
-    THREADPRIO_DEFAULT = 48,      ///< Default thread priority for userland apps
+    THREADPRIO_DEFAULT = 44,      ///< Default thread priority for userland apps
     THREADPRIO_LOWEST = 63,       ///< Lowest thread priority
 };
 
diff --git a/src/core/loader/nro.cpp b/src/core/loader/nro.cpp
index b5133e4d6..3853cfa1a 100644
--- a/src/core/loader/nro.cpp
+++ b/src/core/loader/nro.cpp
@@ -137,7 +137,7 @@ ResultStatus AppLoader_NRO::Load(Kernel::SharedPtr<Kernel::Process>& process) {
     process->address_mappings = default_address_mappings;
     process->resource_limit =
         Kernel::ResourceLimit::GetForCategory(Kernel::ResourceLimitCategory::APPLICATION);
-    process->Run(base_addr, 48, Memory::DEFAULT_STACK_SIZE);
+    process->Run(base_addr, THREADPRIO_DEFAULT, Memory::DEFAULT_STACK_SIZE);
 
     is_loaded = true;
     return ResultStatus::Success;
diff --git a/src/core/loader/nso.cpp b/src/core/loader/nso.cpp
index 3bc10ed0d..962bed2ab 100644
--- a/src/core/loader/nso.cpp
+++ b/src/core/loader/nso.cpp
@@ -165,7 +165,7 @@ ResultStatus AppLoader_NSO::Load(Kernel::SharedPtr<Kernel::Process>& process) {
     process->address_mappings = default_address_mappings;
     process->resource_limit =
         Kernel::ResourceLimit::GetForCategory(Kernel::ResourceLimitCategory::APPLICATION);
-    process->Run(Memory::PROCESS_IMAGE_VADDR, 48, Memory::DEFAULT_STACK_SIZE);
+    process->Run(Memory::PROCESS_IMAGE_VADDR, THREADPRIO_DEFAULT, Memory::DEFAULT_STACK_SIZE);
 
     is_loaded = true;
     return ResultStatus::Success;
-- 
cgit v1.2.3


From 46572d027dc9620ed2b2a50277e6afd2a115ab81 Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Fri, 20 Apr 2018 20:15:16 -0500
Subject: Kernel: Implemented mutex priority inheritance.

Verified with a hwtest and implemented based on reverse engineering.

Thread A's priority will get bumped to the highest priority among all the threads that are waiting for a mutex that A holds.
Once A releases the mutex and ownership is transferred to B, A's priority will return to normal and B's priority will be bumped.
---
 src/core/hle/kernel/mutex.cpp  | 39 +++++++++++++++++++++++++++++++--------
 src/core/hle/kernel/svc.cpp    |  9 +++++++++
 src/core/hle/kernel/thread.cpp | 41 +++++++++++++++++++++++++++++++++++++++--
 src/core/hle/kernel/thread.h   | 15 +++++++++++++++
 4 files changed, 94 insertions(+), 10 deletions(-)

(limited to 'src/core')

diff --git a/src/core/hle/kernel/mutex.cpp b/src/core/hle/kernel/mutex.cpp
index 5cc0bd266..63733ad79 100644
--- a/src/core/hle/kernel/mutex.cpp
+++ b/src/core/hle/kernel/mutex.cpp
@@ -18,13 +18,13 @@ namespace Kernel {
 
 /// Returns the number of threads that are waiting for a mutex, and the highest priority one among
 /// those.
-static std::pair<SharedPtr<Thread>, u32> GetHighestPriorityMutexWaitingThread(VAddr mutex_addr) {
-    auto& thread_list = Core::System::GetInstance().Scheduler().GetThreadList();
+static std::pair<SharedPtr<Thread>, u32> GetHighestPriorityMutexWaitingThread(
+    SharedPtr<Thread> current_thread, VAddr mutex_addr) {
 
     SharedPtr<Thread> highest_priority_thread;
     u32 num_waiters = 0;
 
-    for (auto& thread : thread_list) {
+    for (auto& thread : current_thread->wait_mutex_threads) {
         if (thread->mutex_wait_address != mutex_addr)
             continue;
 
@@ -40,6 +40,21 @@ static std::pair<SharedPtr<Thread>, u32> GetHighestPriorityMutexWaitingThread(VA
     return {highest_priority_thread, num_waiters};
 }
 
+/// Update the mutex owner field of all threads waiting on the mutex to point to the new owner.
+static void TransferMutexOwnership(VAddr mutex_addr, SharedPtr<Thread> current_thread,
+                                   SharedPtr<Thread> new_owner) {
+    auto threads = current_thread->wait_mutex_threads;
+    for (auto& thread : threads) {
+        if (thread->mutex_wait_address != mutex_addr)
+            continue;
+
+        ASSERT(thread->lock_owner == current_thread);
+        current_thread->RemoveMutexWaiter(thread);
+        if (new_owner != thread)
+            new_owner->AddMutexWaiter(thread);
+    }
+}
+
 ResultCode Mutex::TryAcquire(VAddr address, Handle holding_thread_handle,
                              Handle requesting_thread_handle) {
     // The mutex address must be 4-byte aligned
@@ -65,11 +80,14 @@ ResultCode Mutex::TryAcquire(VAddr address, Handle holding_thread_handle,
         return ERR_INVALID_HANDLE;
 
     // Wait until the mutex is released
-    requesting_thread->mutex_wait_address = address;
-    requesting_thread->wait_handle = requesting_thread_handle;
+    GetCurrentThread()->mutex_wait_address = address;
+    GetCurrentThread()->wait_handle = requesting_thread_handle;
 
-    requesting_thread->status = THREADSTATUS_WAIT_MUTEX;
-    requesting_thread->wakeup_callback = nullptr;
+    GetCurrentThread()->status = THREADSTATUS_WAIT_MUTEX;
+    GetCurrentThread()->wakeup_callback = nullptr;
+
+    // Update the lock holder thread's priority to prevent priority inversion.
+    holding_thread->AddMutexWaiter(GetCurrentThread());
 
     Core::System::GetInstance().PrepareReschedule();
 
@@ -82,14 +100,18 @@ ResultCode Mutex::Release(VAddr address) {
         return ResultCode(ErrorModule::Kernel, ErrCodes::MisalignedAddress);
     }
 
-    auto [thread, num_waiters] = GetHighestPriorityMutexWaitingThread(address);
+    auto [thread, num_waiters] = GetHighestPriorityMutexWaitingThread(GetCurrentThread(), address);
 
     // There are no more threads waiting for the mutex, release it completely.
     if (thread == nullptr) {
+        ASSERT(GetCurrentThread()->wait_mutex_threads.empty());
         Memory::Write32(address, 0);
         return RESULT_SUCCESS;
     }
 
+    // Transfer the ownership of the mutex from the previous owner to the new one.
+    TransferMutexOwnership(address, GetCurrentThread(), thread);
+
     u32 mutex_value = thread->wait_handle;
 
     if (num_waiters >= 2) {
@@ -103,6 +125,7 @@ ResultCode Mutex::Release(VAddr address) {
     ASSERT(thread->status == THREADSTATUS_WAIT_MUTEX);
     thread->ResumeFromWait();
 
+    thread->lock_owner = nullptr;
     thread->condvar_wait_address = 0;
     thread->mutex_wait_address = 0;
     thread->wait_handle = 0;
diff --git a/src/core/hle/kernel/svc.cpp b/src/core/hle/kernel/svc.cpp
index 082c36caf..a3015cf7a 100644
--- a/src/core/hle/kernel/svc.cpp
+++ b/src/core/hle/kernel/svc.cpp
@@ -621,6 +621,8 @@ static ResultCode WaitProcessWideKeyAtomic(VAddr mutex_addr, VAddr condition_var
 
     current_thread->WakeAfterDelay(nano_seconds);
 
+    // Note: Deliberately don't attempt to inherit the lock owner's priority.
+
     Core::System::GetInstance().PrepareReschedule();
     return RESULT_SUCCESS;
 }
@@ -651,6 +653,11 @@ static ResultCode SignalProcessWideKey(VAddr condition_variable_addr, s32 target
             ASSERT(thread->status == THREADSTATUS_WAIT_MUTEX);
             thread->ResumeFromWait();
 
+            auto lock_owner = thread->lock_owner;
+            if (lock_owner)
+                lock_owner->RemoveMutexWaiter(thread);
+
+            thread->lock_owner = nullptr;
             thread->mutex_wait_address = 0;
             thread->condvar_wait_address = 0;
             thread->wait_handle = 0;
@@ -666,6 +673,8 @@ static ResultCode SignalProcessWideKey(VAddr condition_variable_addr, s32 target
             // Signal that the mutex now has a waiting thread.
             Memory::Write32(thread->mutex_wait_address, mutex_val | Mutex::MutexHasWaitersFlag);
 
+            owner->AddMutexWaiter(thread);
+
             Core::System::GetInstance().PrepareReschedule();
         }
 
diff --git a/src/core/hle/kernel/thread.cpp b/src/core/hle/kernel/thread.cpp
index 16d9b9e36..36222d45f 100644
--- a/src/core/hle/kernel/thread.cpp
+++ b/src/core/hle/kernel/thread.cpp
@@ -129,6 +129,11 @@ static void ThreadWakeupCallback(u64 thread_handle, int cycles_late) {
         thread->mutex_wait_address = 0;
         thread->condvar_wait_address = 0;
         thread->wait_handle = 0;
+
+        auto lock_owner = thread->lock_owner;
+        // Threads waking up by timeout from WaitProcessWideKey do not perform priority inheritance
+        // and don't have a lock owner.
+        ASSERT(lock_owner == nullptr);
     }
 
     if (resume)
@@ -325,8 +330,8 @@ ResultVal<SharedPtr<Thread>> Thread::Create(std::string name, VAddr entry_point,
 void Thread::SetPriority(u32 priority) {
     ASSERT_MSG(priority <= THREADPRIO_LOWEST && priority >= THREADPRIO_HIGHEST,
                "Invalid priority value.");
-    Core::System::GetInstance().Scheduler().SetThreadPriority(this, priority);
-    nominal_priority = current_priority = priority;
+    nominal_priority = priority;
+    UpdatePriority();
 }
 
 void Thread::BoostPriority(u32 priority) {
@@ -376,6 +381,38 @@ VAddr Thread::GetCommandBufferAddress() const {
     return GetTLSAddress() + CommandHeaderOffset;
 }
 
+void Thread::AddMutexWaiter(SharedPtr<Thread> thread) {
+    thread->lock_owner = this;
+    wait_mutex_threads.emplace_back(std::move(thread));
+    UpdatePriority();
+}
+
+void Thread::RemoveMutexWaiter(SharedPtr<Thread> thread) {
+    boost::remove_erase(wait_mutex_threads, thread);
+    thread->lock_owner = nullptr;
+    UpdatePriority();
+}
+
+void Thread::UpdatePriority() {
+    // Find the highest priority among all the threads that are waiting for this thread's lock
+    u32 new_priority = nominal_priority;
+    for (const auto& thread : wait_mutex_threads) {
+        if (thread->nominal_priority < new_priority)
+            new_priority = thread->nominal_priority;
+    }
+
+    if (new_priority == current_priority)
+        return;
+
+    Core::System::GetInstance().Scheduler().SetThreadPriority(this, new_priority);
+
+    current_priority = new_priority;
+
+    // Recursively update the priority of the thread that depends on the priority of this one.
+    if (lock_owner)
+        lock_owner->UpdatePriority();
+}
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 /**
diff --git a/src/core/hle/kernel/thread.h b/src/core/hle/kernel/thread.h
index 0e0eae28d..e0a3c0934 100644
--- a/src/core/hle/kernel/thread.h
+++ b/src/core/hle/kernel/thread.h
@@ -109,6 +109,15 @@ public:
      */
     void BoostPriority(u32 priority);
 
+    /// Adds a thread to the list of threads that are waiting for a lock held by this thread.
+    void AddMutexWaiter(SharedPtr<Thread> thread);
+
+    /// Removes a thread from the list of threads that are waiting for a lock held by this thread.
+    void RemoveMutexWaiter(SharedPtr<Thread> thread);
+
+    /// Recalculates the current priority taking into account priority inheritance.
+    void UpdatePriority();
+
     /**
      * Gets the thread's thread ID
      * @return The thread's ID
@@ -205,6 +214,12 @@ public:
     // passed to WaitSynchronization1/N.
     std::vector<SharedPtr<WaitObject>> wait_objects;
 
+    /// List of threads that are waiting for a mutex that is held by this thread.
+    std::vector<SharedPtr<Thread>> wait_mutex_threads;
+
+    /// Thread that owns the lock that this thread is waiting for.
+    SharedPtr<Thread> lock_owner;
+
     // If waiting on a ConditionVariable, this is the ConditionVariable  address
     VAddr condvar_wait_address;
     VAddr mutex_wait_address; ///< If waiting on a Mutex, this is the mutex address
-- 
cgit v1.2.3