kernel/thread: Use a regular pointer for the owner/current process

There's no real need to use a shared pointer in these cases, and only
makes object management more fragile in terms of how easy it would be to
introduce cycles. Instead, just do the simple thing of using a regular
pointer. Much of this is just a hold-over from citra anyways.

It also doesn't make sense from a behavioral point of view for a
process' thread to prolong the lifetime of the process itself (the
process is supposed to own the thread, not the other way around).

src/core/arm/dynarmic/arm_dynarmic.cpp

@@ -129,7 +129,7 @@ public:
 };
 
 std::unique_ptr<Dynarmic::A64::Jit> ARM_Dynarmic::MakeJit() const {
-    auto& current_process = Core::CurrentProcess();
+    auto* current_process = Core::CurrentProcess();
     auto** const page_table = current_process->VMManager().page_table.pointers.data();
 
     Dynarmic::A64::UserConfig config;

src/core/core.cpp

@@ -136,7 +136,8 @@ struct System::Impl {
         if (virtual_filesystem == nullptr)
             virtual_filesystem = std::make_shared<FileSys::RealVfsFilesystem>();
 
-        kernel.MakeCurrentProcess(Kernel::Process::Create(kernel, "main"));
+        auto main_process = Kernel::Process::Create(kernel, "main");
+        kernel.MakeCurrentProcess(main_process.get());
 
         cpu_barrier = std::make_shared<CpuBarrier>();
         cpu_exclusive_monitor = Cpu::MakeExclusiveMonitor(cpu_cores.size());
@@ -361,11 +362,11 @@ const std::shared_ptr<Kernel::Scheduler>& System::Scheduler(std::size_t core_ind
     return impl->cpu_cores[core_index]->Scheduler();
 }
 
-Kernel::SharedPtr<Kernel::Process>& System::CurrentProcess() {
+Kernel::Process* System::CurrentProcess() {
     return impl->kernel.CurrentProcess();
 }
 
-const Kernel::SharedPtr<Kernel::Process>& System::CurrentProcess() const {
+const Kernel::Process* System::CurrentProcess() const {
     return impl->kernel.CurrentProcess();
 }
 

src/core/core.h

@@ -174,11 +174,11 @@ public:
     /// Gets the scheduler for the CPU core with the specified index
     const std::shared_ptr<Kernel::Scheduler>& Scheduler(std::size_t core_index);
 
-    /// Provides a reference to the current process
+    /// Provides a pointer to the current process
-    Kernel::SharedPtr<Kernel::Process>& CurrentProcess();
+    Kernel::Process* CurrentProcess();
 
-    /// Provides a constant reference to the current process.
+    /// Provides a constant pointer to the current process.
-    const Kernel::SharedPtr<Kernel::Process>& CurrentProcess() const;
+    const Kernel::Process* CurrentProcess() const;
 
     /// Provides a reference to the kernel instance.
     Kernel::KernelCore& Kernel();
@@ -246,7 +246,7 @@ inline TelemetrySession& Telemetry() {
     return System::GetInstance().TelemetrySession();
 }
 
-inline Kernel::SharedPtr<Kernel::Process>& CurrentProcess() {
+inline Kernel::Process* CurrentProcess() {
     return System::GetInstance().CurrentProcess();
 }
 

src/core/hle/kernel/kernel.cpp

@@ -116,7 +116,7 @@ struct KernelCore::Impl {
         next_thread_id = 1;
 
         process_list.clear();
-        current_process.reset();
+        current_process = nullptr;
 
         handle_table.Clear();
         resource_limits.fill(nullptr);
@@ -207,7 +207,7 @@ struct KernelCore::Impl {
 
     // Lists all processes that exist in the current session.
     std::vector<SharedPtr<Process>> process_list;
-    SharedPtr<Process> current_process;
+    Process* current_process = nullptr;
 
     Kernel::HandleTable handle_table;
     std::array<SharedPtr<ResourceLimit>, 4> resource_limits;
@@ -266,15 +266,15 @@ void KernelCore::AppendNewProcess(SharedPtr<Process> process) {
     impl->process_list.push_back(std::move(process));
 }
 
-void KernelCore::MakeCurrentProcess(SharedPtr<Process> process) {
+void KernelCore::MakeCurrentProcess(Process* process) {
-    impl->current_process = std::move(process);
+    impl->current_process = process;
 }
 
-SharedPtr<Process>& KernelCore::CurrentProcess() {
+Process* KernelCore::CurrentProcess() {
     return impl->current_process;
 }
 
-const SharedPtr<Process>& KernelCore::CurrentProcess() const {
+const Process* KernelCore::CurrentProcess() const {
     return impl->current_process;
 }
 

src/core/hle/kernel/kernel.h

@@ -66,13 +66,13 @@ public:
     void AppendNewProcess(SharedPtr<Process> process);
 
     /// Makes the given process the new current process.
-    void MakeCurrentProcess(SharedPtr<Process> process);
+    void MakeCurrentProcess(Process* process);
 
-    /// Retrieves a reference to the current process.
+    /// Retrieves a pointer to the current process.
-    SharedPtr<Process>& CurrentProcess();
+    Process* CurrentProcess();
 
-    /// Retrieves a const reference to the current process.
+    /// Retrieves a const pointer to the current process.
-    const SharedPtr<Process>& CurrentProcess() const;
+    const Process* CurrentProcess() const;
 
     /// Adds a port to the named port table
     void AddNamedPort(std::string name, SharedPtr<ClientPort> port);

src/core/hle/kernel/scheduler.cpp

@@ -9,7 +9,7 @@
 #include "common/logging/log.h"
 #include "core/arm/arm_interface.h"
 #include "core/core.h"
-#include "core/core_timing.h"
+#include "core/hle/kernel/kernel.h"
 #include "core/hle/kernel/process.h"
 #include "core/hle/kernel/scheduler.h"
 
@@ -78,16 +78,16 @@ void Scheduler::SwitchContext(Thread* new_thread) {
         // Cancel any outstanding wakeup events for this thread
         new_thread->CancelWakeupTimer();
 
-        auto previous_process = Core::CurrentProcess();
+        auto* const previous_process = Core::CurrentProcess();
 
         current_thread = new_thread;
 
         ready_queue.remove(new_thread->GetPriority(), new_thread);
         new_thread->SetStatus(ThreadStatus::Running);
 
-        const auto thread_owner_process = current_thread->GetOwnerProcess();
+        auto* const thread_owner_process = current_thread->GetOwnerProcess();
         if (previous_process != thread_owner_process) {
-            Core::CurrentProcess() = thread_owner_process;
+            Core::System::GetInstance().Kernel().MakeCurrentProcess(thread_owner_process);
             SetCurrentPageTable(&Core::CurrentProcess()->VMManager().page_table);
         }
 

src/core/hle/kernel/svc.cpp

@@ -341,7 +341,7 @@ static ResultCode GetInfo(u64* result, u64 info_id, u64 handle, u64 info_sub_id)
     LOG_TRACE(Kernel_SVC, "called info_id=0x{:X}, info_sub_id=0x{:X}, handle=0x{:08X}", info_id,
               info_sub_id, handle);
 
-    const auto& current_process = Core::CurrentProcess();
+    const auto* current_process = Core::CurrentProcess();
     const auto& vm_manager = current_process->VMManager();
 
     switch (static_cast<GetInfoType>(info_id)) {
@@ -439,7 +439,7 @@ static ResultCode GetThreadContext(VAddr thread_context, Handle handle) {
         return ERR_INVALID_HANDLE;
     }
 
-    const auto current_process = Core::CurrentProcess();
+    const auto* current_process = Core::CurrentProcess();
     if (thread->GetOwnerProcess() != current_process) {
         return ERR_INVALID_HANDLE;
     }
@@ -531,7 +531,7 @@ static ResultCode MapSharedMemory(Handle shared_memory_handle, VAddr addr, u64 s
         return ERR_INVALID_HANDLE;
     }
 
-    return shared_memory->Map(Core::CurrentProcess().get(), addr, permissions_type,
+    return shared_memory->Map(Core::CurrentProcess(), addr, permissions_type,
                               MemoryPermission::DontCare);
 }
 
@@ -550,7 +550,7 @@ static ResultCode UnmapSharedMemory(Handle shared_memory_handle, VAddr addr, u64
     auto& kernel = Core::System::GetInstance().Kernel();
     auto shared_memory = kernel.HandleTable().Get<SharedMemory>(shared_memory_handle);
 
-    return shared_memory->Unmap(Core::CurrentProcess().get(), addr);
+    return shared_memory->Unmap(Core::CurrentProcess(), addr);
 }
 
 /// Query process memory
@@ -588,7 +588,7 @@ static ResultCode QueryMemory(MemoryInfo* memory_info, PageInfo* page_info, VAdd
 
 /// Exits the current process
 static void ExitProcess() {
-    auto& current_process = Core::CurrentProcess();
+    auto* current_process = Core::CurrentProcess();
 
     LOG_INFO(Kernel_SVC, "Process {} exiting", current_process->GetProcessID());
     ASSERT_MSG(current_process->GetStatus() == ProcessStatus::Running,
@@ -636,7 +636,7 @@ static ResultCode CreateThread(Handle* out_handle, VAddr entry_point, u64 arg, V
     auto& kernel = Core::System::GetInstance().Kernel();
     CASCADE_RESULT(SharedPtr<Thread> thread,
                    Thread::Create(kernel, name, entry_point, priority, arg, processor_id, stack_top,
-                                  Core::CurrentProcess()));
+                                  *Core::CurrentProcess()));
     const auto new_guest_handle = kernel.HandleTable().Create(thread);
     if (new_guest_handle.Failed()) {
         return new_guest_handle.Code();

src/core/hle/kernel/thread.cpp

@@ -194,7 +194,7 @@ static void ResetThreadContext(Core::ARM_Interface::ThreadContext& context, VAdd
 
 ResultVal<SharedPtr<Thread>> Thread::Create(KernelCore& kernel, std::string name, VAddr entry_point,
                                             u32 priority, u64 arg, s32 processor_id,
-                                            VAddr stack_top, SharedPtr<Process> owner_process) {
+                                            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);
@@ -208,7 +208,7 @@ ResultVal<SharedPtr<Thread>> Thread::Create(KernelCore& kernel, std::string name
 
     // TODO(yuriks): Other checks, returning 0xD9001BEA
 
-    if (!Memory::IsValidVirtualAddress(*owner_process, entry_point)) {
+    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);
@@ -232,7 +232,7 @@ ResultVal<SharedPtr<Thread>> Thread::Create(KernelCore& kernel, std::string name
     thread->wait_handle = 0;
     thread->name = std::move(name);
     thread->callback_handle = kernel.ThreadWakeupCallbackHandleTable().Create(thread).Unwrap();
-    thread->owner_process = owner_process;
+    thread->owner_process = &owner_process;
     thread->scheduler = Core::System::GetInstance().Scheduler(processor_id).get();
     thread->scheduler->AddThread(thread, priority);
     thread->tls_address = thread->owner_process->MarkNextAvailableTLSSlotAsUsed(*thread);
@@ -264,7 +264,7 @@ SharedPtr<Thread> SetupMainThread(KernelCore& kernel, VAddr entry_point, u32 pri
     // Initialize new "main" thread
     const VAddr stack_top = owner_process.VMManager().GetTLSIORegionEndAddress();
     auto thread_res = Thread::Create(kernel, "main", entry_point, priority, 0, THREADPROCESSORID_0,
-                                     stack_top, &owner_process);
+                                     stack_top, owner_process);
 
     SharedPtr<Thread> thread = std::move(thread_res).Unwrap();
 

src/core/hle/kernel/thread.h

@@ -89,7 +89,7 @@ public:
     static ResultVal<SharedPtr<Thread>> Create(KernelCore& kernel, std::string name,
                                                VAddr entry_point, u32 priority, u64 arg,
                                                s32 processor_id, VAddr stack_top,
-                                               SharedPtr<Process> owner_process);
+                                               Process& owner_process);
 
     std::string GetName() const override {
         return name;
@@ -262,11 +262,11 @@ public:
         return processor_id;
     }
 
-    SharedPtr<Process>& GetOwnerProcess() {
+    Process* GetOwnerProcess() {
         return owner_process;
     }
 
-    const SharedPtr<Process>& GetOwnerProcess() const {
+    const Process* GetOwnerProcess() const {
         return owner_process;
     }
 
@@ -386,7 +386,7 @@ private:
     u64 tpidr_el0 = 0;     ///< TPIDR_EL0 read/write system register.
 
     /// Process that owns this thread
-    SharedPtr<Process> owner_process;
+    Process* owner_process;
 
     /// Objects that the thread is waiting on, in the same order as they were
     /// passed to WaitSynchronization1/N.

src/tests/core/arm/arm_test_common.cpp

@@ -15,7 +15,8 @@ namespace ArmTests {
 TestEnvironment::TestEnvironment(bool mutable_memory_)
     : mutable_memory(mutable_memory_), test_memory(std::make_shared<TestMemory>(this)) {
 
-    Core::CurrentProcess() = Kernel::Process::Create(kernel, "");
+    auto process = Kernel::Process::Create(kernel, "");
+    kernel.MakeCurrentProcess(process.get());
     page_table = &Core::CurrentProcess()->VMManager().page_table;
 
     std::fill(page_table->pointers.begin(), page_table->pointers.end(), nullptr);