kern: implement SvcSignalToAddress, SvcWaitForAddress

libraries/libmesosphere/source/kern_k_address_arbiter.cpp

@@ -19,28 +19,212 @@ namespace ams::kern {
 
     namespace {
 
-        constinit KThread g_arbiter_compare_thread;
-
         ALWAYS_INLINE bool ReadFromUser(s32 *out, KProcessAddress address) {
             return UserspaceAccess::CopyMemoryFromUserSize32Bit(out, GetVoidPointer(address));
         }
 
+        ALWAYS_INLINE bool DecrementIfLessThan(s32 *out, KProcessAddress address, s32 value) {
+            KScopedInterruptDisable di;
+
+            if (!cpu::CanAccessAtomic(address)) {
+                return false;
+            }
+
+            return UserspaceAccess::DecrementIfLessThanAtomic(out, GetPointer<s32>(address), value);
+        }
+
+        ALWAYS_INLINE bool UpdateIfEqual(s32 *out, KProcessAddress address, s32 value, s32 new_value) {
+            KScopedInterruptDisable di;
+
+            if (!cpu::CanAccessAtomic(address)) {
+                return false;
+            }
+
+            return UserspaceAccess::UpdateIfEqualAtomic(out, GetPointer<s32>(address), value, new_value);
+        }
+
     }
 
     Result KAddressArbiter::Signal(uintptr_t addr, s32 count) {
-        MESOSPHERE_UNIMPLEMENTED();
+        /* Perform signaling. */
+        s32 num_waiters = 0;
+        {
+            KScopedSchedulerLock sl;
+            g_cv_arbiter_compare_thread.SetupForAddressArbiterCompare(addr, -1);
+
+            auto it = this->tree.nfind(g_cv_arbiter_compare_thread);
+            while ((it != this->tree.end()) && (count <= 0 || num_waiters < count) && (it->GetAddressArbiterKey() == addr)) {
+                KThread *target_thread = std::addressof(*it);
+                target_thread->SetSyncedObject(nullptr, ResultSuccess());
+
+                AMS_ASSERT(target_thread->IsWaitingForAddressArbiter());
+                target_thread->Wakeup();
+
+                it = this->tree.erase(it);
+                target_thread->ClearAddressArbiter();
+                ++num_waiters;
+            }
+        }
+        return ResultSuccess();
     }
 
     Result KAddressArbiter::SignalAndIncrementIfEqual(uintptr_t addr, s32 value, s32 count) {
-        MESOSPHERE_UNIMPLEMENTED();
+        /* Perform signaling. */
+        s32 num_waiters = 0;
+        {
+            KScopedSchedulerLock sl;
+            g_cv_arbiter_compare_thread.SetupForAddressArbiterCompare(addr, -1);
+
+            auto it = this->tree.nfind(g_cv_arbiter_compare_thread);
+
+            /* Check the userspace value. */
+            s32 user_value;
+            R_UNLESS(UpdateIfEqual(std::addressof(user_value), addr, value, value + 1), svc::ResultInvalidCurrentMemory());
+            R_UNLESS(user_value == value,                                               svc::ResultInvalidState());
+
+            while ((it != this->tree.end()) && (count <= 0 || num_waiters < count) && (it->GetAddressArbiterKey() == addr)) {
+                KThread *target_thread = std::addressof(*it);
+                target_thread->SetSyncedObject(nullptr, ResultSuccess());
+
+                AMS_ASSERT(target_thread->IsWaitingForAddressArbiter());
+                target_thread->Wakeup();
+
+                it = this->tree.erase(it);
+                target_thread->ClearAddressArbiter();
+                ++num_waiters;
+            }
+        }
+        return ResultSuccess();
     }
 
     Result KAddressArbiter::SignalAndModifyByWaitingCountIfEqual(uintptr_t addr, s32 value, s32 count) {
-        MESOSPHERE_UNIMPLEMENTED();
+        /* Perform signaling. */
+        s32 num_waiters = 0;
+        {
+            KScopedSchedulerLock sl;
+            g_cv_arbiter_compare_thread.SetupForAddressArbiterCompare(addr, -1);
+
+            auto it = this->tree.nfind(g_cv_arbiter_compare_thread);
+
+            /* Determine the updated value. */
+            s32 new_value;
+            if (count <= 0) {
+                if ((it != this->tree.end()) && (it->GetAddressArbiterKey() == addr)) {
+                    new_value = value - 1;
+                } else {
+                    new_value = value + 1;
+                }
+            } else {
+                auto tmp_it = it;
+                int tmp_num_waiters = 0;
+                while ((tmp_it != this->tree.end()) && (tmp_it->GetAddressArbiterKey() == addr) && (tmp_num_waiters < count + 1)) {
+                    ++tmp_num_waiters;
+                    ++tmp_it;
+                }
+
+                if (tmp_num_waiters == 0) {
+                    new_value = value + 1;
+                } else if (tmp_num_waiters <= count) {
+                    new_value = value - 1;
+                } else {
+                    new_value = value;
+                }
+            }
+
+            /* Check the userspace value. */
+            s32 user_value;
+            bool succeeded;
+            if (value != new_value) {
+                succeeded = UpdateIfEqual(std::addressof(user_value), addr, value, new_value);
+            } else {
+                succeeded = ReadFromUser(std::addressof(user_value), addr);
+            }
+
+            R_UNLESS(succeeded,           svc::ResultInvalidCurrentMemory());
+            R_UNLESS(user_value == value, svc::ResultInvalidState());
+
+            while ((it != this->tree.end()) && (count <= 0 || num_waiters < count) && (it->GetAddressArbiterKey() == addr)) {
+                KThread *target_thread = std::addressof(*it);
+                target_thread->SetSyncedObject(nullptr, ResultSuccess());
+
+                AMS_ASSERT(target_thread->IsWaitingForAddressArbiter());
+                target_thread->Wakeup();
+
+                it = this->tree.erase(it);
+                target_thread->ClearAddressArbiter();
+                ++num_waiters;
+            }
+        }
+        return ResultSuccess();
     }
 
     Result KAddressArbiter::WaitIfLessThan(uintptr_t addr, s32 value, bool decrement, s64 timeout) {
-        MESOSPHERE_UNIMPLEMENTED();
+        /* Prepare to wait. */
+        KThread *cur_thread = GetCurrentThreadPointer();
+        KHardwareTimer *timer;
+
+        {
+            KScopedSchedulerLockAndSleep slp(std::addressof(timer), cur_thread, timeout);
+
+            /* Check that the thread isn't terminating. */
+            if (cur_thread->IsTerminationRequested()) {
+                slp.CancelSleep();
+                return svc::ResultTerminationRequested();
+            }
+
+            /* Set the synced object. */
+            cur_thread->SetSyncedObject(nullptr, ams::svc::ResultTimedOut());
+
+            /* Read the value from userspace. */
+            s32 user_value;
+            bool succeeded;
+            if (decrement) {
+                succeeded = DecrementIfLessThan(std::addressof(user_value), addr, value);
+            } else {
+                succeeded = ReadFromUser(std::addressof(user_value), addr);
+            }
+
+            if (!succeeded) {
+                slp.CancelSleep();
+                return svc::ResultInvalidCurrentMemory();
+            }
+
+            /* Check that the value is less than the specified one. */
+            if (user_value >= value) {
+                slp.CancelSleep();
+                return svc::ResultInvalidState();
+            }
+
+            /* Check that the timeout is non-zero. */
+            if (timeout == 0) {
+                slp.CancelSleep();
+                return svc::ResultTimedOut();
+            }
+
+            /* Set the arbiter. */
+            cur_thread->SetAddressArbiter(std::addressof(this->tree), addr);
+            this->tree.insert(*cur_thread);
+            cur_thread->SetState(KThread::ThreadState_Waiting);
+        }
+
+        /* Cancel the timer wait. */
+        if (timer != nullptr) {
+            timer->CancelTask(cur_thread);
+        }
+
+        /* Remove from the address arbiter. */
+        {
+            KScopedSchedulerLock sl;
+
+            if (cur_thread->IsWaitingForAddressArbiter()) {
+                this->tree.erase(this->tree.iterator_to(*cur_thread));
+                cur_thread->ClearAddressArbiter();
+            }
+        }
+
+        /* Get the result. */
+        KSynchronizationObject *dummy;
+        return cur_thread->GetWaitResult(std::addressof(dummy));
     }
 
     Result KAddressArbiter::WaitIfEqual(uintptr_t addr, s32 value, s64 timeout) {