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.
This commit is contained in:
Subv 2018-04-20 12:01:14 -05:00
parent 326b044c19
commit e81a2080eb
6 changed files with 126 additions and 22 deletions

View file

@ -20,6 +20,7 @@ enum {
MaxConnectionsReached = 52,
// Confirmed Switch OS error codes
MisalignedAddress = 102,
InvalidHandle = 114,
Timeout = 117,
SynchronizationCanceled = 118,

View file

@ -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

View file

@ -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;

View file

@ -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

View file

@ -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;

View file

@ -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;