os: implement LightSemaphore

libraries/libstratosphere/include/stratosphere/os.hpp

@@ -46,5 +46,5 @@
 #include <stratosphere/os/os_message_queue.hpp>
 #include <stratosphere/os/os_light_event.hpp>
 #include <stratosphere/os/os_light_message_queue.hpp>
-//#include <stratosphere/os/os_light_semaphore.hpp>
+#include <stratosphere/os/os_light_semaphore.hpp>
 #include <stratosphere/os/os_waitable.hpp>

libraries/libstratosphere/include/stratosphere/os/os_light_semaphore.hpp

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+#include <stratosphere/os/os_light_semaphore_types.hpp>
+#include <stratosphere/os/os_light_semaphore_api.hpp>
+
+namespace ams::os {
+
+    class LightSemaphore {
+        NON_COPYABLE(LightSemaphore);
+        NON_MOVEABLE(LightSemaphore);
+        private:
+            LightSemaphoreType m_sema;
+        public:
+            explicit LightSemaphore(s32 count, s32 max_count) {
+                InitializeLightSemaphore(std::addressof(m_sema), count, max_count);
+            }
+
+            ~LightSemaphore() { FinalizeLightSemaphore(std::addressof(m_sema)); }
+
+            void Acquire() {
+                return os::AcquireLightSemaphore(std::addressof(m_sema));
+            }
+
+            bool TryAcquire() {
+                return os::TryAcquireLightSemaphore(std::addressof(m_sema));
+            }
+
+            bool TimedAcquire(TimeSpan timeout) {
+                return os::TimedAcquireLightSemaphore(std::addressof(m_sema), timeout);
+            }
+
+            void Release() {
+                return os::ReleaseLightSemaphore(std::addressof(m_sema));
+            }
+
+            void Release(s32 count) {
+                return os::ReleaseLightSemaphore(std::addressof(m_sema), count);
+            }
+
+            s32 GetCurrentCount() const {
+                return os::GetCurrentLightSemaphoreCount(std::addressof(m_sema));
+            }
+
+            operator LightSemaphoreType &() {
+                return m_sema;
+            }
+
+            operator const LightSemaphoreType &() const {
+                return m_sema;
+            }
+
+            LightSemaphoreType *GetBase() {
+                return std::addressof(m_sema);
+            }
+    };
+
+}

libraries/libstratosphere/include/stratosphere/os/os_light_semaphore_api.hpp

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+#include <vapours.hpp>
+
+namespace ams::os {
+
+    struct LightSemaphoreType;
+
+    void InitializeLightSemaphore(LightSemaphoreType *sema, s32 count, s32 max_count);
+    void FinalizeLightSemaphore(LightSemaphoreType *sema);
+
+    void AcquireLightSemaphore(LightSemaphoreType *sema);
+    bool TryAcquireLightSemaphore(LightSemaphoreType *sema);
+    bool TimedAcquireLightSemaphore(LightSemaphoreType *sema, TimeSpan timeout);
+
+    void ReleaseLightSemaphore(LightSemaphoreType *sema);
+    void ReleaseLightSemaphore(LightSemaphoreType *sema, s32 count);
+
+    s32 GetCurrentLightSemaphoreCount(const LightSemaphoreType *sema);
+
+}

libraries/libstratosphere/include/stratosphere/os/os_light_semaphore_types.hpp

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+#include <vapours.hpp>
+#include <stratosphere/os/impl/os_internal_critical_section.hpp>
+#include <stratosphere/os/impl/os_internal_busy_mutex.hpp>
+#include <stratosphere/os/impl/os_internal_light_event.hpp>
+
+namespace ams::os {
+
+    namespace impl {
+
+        using LightSemaphoreMutex        = InternalBusyMutex;
+        using LightSemaphoreMutexStorage = InternalBusyMutexStorage;
+
+    }
+
+    struct LightSemaphoreType {
+        enum State {
+            State_NotInitialized = 0,
+            State_Initialized    = 1,
+        };
+
+        u8 state;
+        s32 count;
+        s32 max_count;
+
+        mutable impl::LightSemaphoreMutexStorage mutex;
+        impl::InternalLightEventStorage ev_not_zero;
+    };
+    static_assert(std::is_trivial<LightSemaphoreType>::value);
+
+}

libraries/libstratosphere/include/stratosphere/os/os_semaphore_types.hpp

@@ -35,8 +35,8 @@ namespace ams::os {
 
         util::TypedStorage<impl::WaitableObjectList, sizeof(util::IntrusiveListNode), alignof(util::IntrusiveListNode)> waitlist;
         u8 state;
-        int count;
-        int max_count;
+        s32 count;
+        s32 max_count;
 
         impl::InternalCriticalSectionStorage cs_sema;
         impl::InternalConditionVariableStorage cv_not_zero;

libraries/libstratosphere/source/os/os_light_semaphore.cpp

@@ -0,0 +1,179 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+#include "impl/os_timeout_helper.hpp"
+
+namespace ams::os {
+
+    void InitializeLightSemaphore(LightSemaphoreType *sema, s32 count, s32 max_count) {
+        /* Check pre-conditions. */
+        AMS_ASSERT(max_count >= 1);
+        AMS_ASSERT(0 <= count && count <= max_count);
+
+        /* Setup objects. */
+        util::ConstructAt(sema->mutex);
+        util::ConstructAt(sema->ev_not_zero, count > 0);
+
+        /* Set member variables. */
+        sema->count     = count;
+        sema->max_count = max_count;
+
+        /* Mark initialized. */
+        sema->state = LightSemaphoreType::State_Initialized;
+    }
+
+    void FinalizeLightSemaphore(LightSemaphoreType *sema) {
+        /* Check pre-conditions. */
+        AMS_ASSERT(sema->state == LightSemaphoreType::State_Initialized);
+
+        /* Mark uninitialized. */
+        sema->state = LightSemaphoreType::State_NotInitialized;
+
+        /* Destroy objects. */
+        util::DestroyAt(sema->mutex);
+        util::DestroyAt(sema->ev_not_zero);
+    }
+
+    void AcquireLightSemaphore(LightSemaphoreType *sema) {
+        /* Check pre-conditions. */
+        AMS_ASSERT(sema->state == LightSemaphoreType::State_Initialized);
+
+        /* Repeatedly try to acquire the semaphore. */
+        while (true) {
+            /* Try to acquire the semaphore. */
+            {
+                /* Acquire exclusive access to the semaphore. */
+                std::scoped_lock lk(util::GetReference(sema->mutex));
+
+                /* If we can, acquire. */
+                if (sema->count > 0) {
+                    --sema->count;
+                    return;
+                }
+
+                /* Ensure that we can wait once we're unlocked. */
+                util::GetReference(sema->ev_not_zero).Clear();
+            }
+
+            /* Wait until we can try again. */
+            util::GetReference(sema->ev_not_zero).WaitWithManualClear();
+        }
+    }
+
+    bool TryAcquireLightSemaphore(LightSemaphoreType *sema) {
+        /* Check pre-conditions. */
+        AMS_ASSERT(sema->state == LightSemaphoreType::State_Initialized);
+
+        /* Acquire exclusive access to the semaphore. */
+        std::scoped_lock lk(util::GetReference(sema->mutex));
+
+        /* Try to acquire. */
+        if (sema->count > 0) {
+            --sema->count;
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    bool TimedAcquireLightSemaphore(LightSemaphoreType *sema, TimeSpan timeout) {
+        /* Check pre-conditions. */
+        AMS_ASSERT(sema->state == LightSemaphoreType::State_Initialized);
+        AMS_ASSERT(timeout.GetNanoSeconds() >= 0);
+
+        /* Create timeout helper. */
+        impl::TimeoutHelper timeout_helper(timeout);
+
+        /* Repeatedly try to acquire the semaphore. */
+        while (true) {
+            /* Try to acquire the semaphore. */
+            {
+                /* Acquire exclusive access to the semaphore. */
+                std::scoped_lock lk(util::GetReference(sema->mutex));
+
+                /* If we can, acquire. */
+                if (sema->count > 0) {
+                    --sema->count;
+                    return true;
+                }
+
+                /* Ensure that we can wait once we're unlocked. */
+                util::GetReference(sema->ev_not_zero).Clear();
+            }
+
+            /* Check if we're timed out. */
+            if (timeout_helper.TimedOut()) {
+                return false;
+            }
+
+            /* Wait until we can try again. */
+            util::GetReference(sema->ev_not_zero).TimedWaitWithManualClear(timeout_helper);
+        }
+    }
+
+    void ReleaseLightSemaphore(LightSemaphoreType *sema) {
+        /* Check pre-conditions. */
+        AMS_ASSERT(sema->state == LightSemaphoreType::State_Initialized);
+
+        /* Release the semaphore. */
+        {
+            /* Acquire exclusive access to the semaphore. */
+            std::scoped_lock lk(util::GetReference(sema->mutex));
+
+            /* Check that we can release. */
+            AMS_ASSERT(sema->count + 1 <= sema->max_count);
+
+            /* Release. */
+            ++sema->count;
+        }
+
+        /* Signal that we released. */
+        util::GetReference(sema->ev_not_zero).SignalWithManualClear();
+    }
+
+    void ReleaseLightSemaphore(LightSemaphoreType *sema, s32 count) {
+        /* Check pre-conditions. */
+        AMS_ASSERT(sema->state == LightSemaphoreType::State_Initialized);
+        AMS_ASSERT(count >= 1);
+
+        /* Release the semaphore. */
+        {
+            /* Acquire exclusive access to the semaphore. */
+            std::scoped_lock lk(util::GetReference(sema->mutex));
+
+            /* Check that we can release. */
+            AMS_ASSERT(sema->count + count <= sema->max_count);
+
+            /* Release. */
+            sema->count += count;
+        }
+
+        /* Signal that we released. */
+        util::GetReference(sema->ev_not_zero).SignalWithManualClear();
+    }
+
+    s32 GetCurrentLightSemaphoreCount(const LightSemaphoreType *sema) {
+        /* Check pre-conditions. */
+        AMS_ASSERT(sema->state == LightSemaphoreType::State_Initialized);
+
+        /* Acquire exclusive access to the semaphore. */
+        std::scoped_lock lk(util::GetReference(sema->mutex));
+
+        /* Get the count. */
+        return sema->count;
+    }
+
+}

libraries/libstratosphere/source/os/os_semaphore.cpp

@@ -15,13 +15,14 @@
  */
 #include <stratosphere.hpp>
 #include "impl/os_waitable_object_list.hpp"
+#include "impl/os_waitable_holder_impl.hpp"
 #include "impl/os_timeout_helper.hpp"
 
 namespace ams::os {
 
     void InitializeSemaphore(SemaphoreType *sema, s32 count, s32 max_count) {
         AMS_ASSERT(max_count >= 1);
-        AMS_ASSERT(count     >= 0);
+        AMS_ASSERT(0 <= count && count <= max_count);
 
         /* Setup objects. */
         util::ConstructAt(sema->cs_sema);
@@ -141,6 +142,12 @@ namespace ams::os {
         return sema->count;
     }
 
-    // void InitializeWaitableHolder(WaitableHolderType *waitable_holder, SemaphoreType *sema);
+    void InitializeWaitableHolder(WaitableHolderType *waitable_holder, SemaphoreType *sema) {
+        AMS_ASSERT(sema->state == SemaphoreType::State_Initialized);
+
+        util::ConstructAt(GetReference(waitable_holder->impl_storage).holder_of_semaphore_storage, sema);
+
+        waitable_holder->user_data = 0;
+    }
 
 }