From 970b85bf9a21b86df3f57eb8eaa8c5d2ab331cde Mon Sep 17 00:00:00 2001
From: Michael Scire <SciresM@gmail.com>
Date: Sun, 26 Apr 2020 02:35:10 -0700
Subject: [PATCH] kern: implement KUnsafeMemory

---
 .../libmesosphere/include/mesosphere.hpp      |  1 +
 .../mesosphere/kern_k_unsafe_memory.hpp       | 78 +++++++++++++++++++
 .../include/mesosphere/kern_kernel.hpp        |  6 ++
 .../source/kern_kernel_instantiations.cpp     |  1 +
 4 files changed, 86 insertions(+)
 create mode 100644 libraries/libmesosphere/include/mesosphere/kern_k_unsafe_memory.hpp

diff --git a/libraries/libmesosphere/include/mesosphere.hpp b/libraries/libmesosphere/include/mesosphere.hpp
index ab2d02bcd..279eb2a0a 100644
--- a/libraries/libmesosphere/include/mesosphere.hpp
+++ b/libraries/libmesosphere/include/mesosphere.hpp
@@ -79,6 +79,7 @@
 
 /* More Miscellaneous objects. */
 #include <mesosphere/kern_k_object_name.hpp>
+#include <mesosphere/kern_k_unsafe_memory.hpp>
 #include <mesosphere/kern_k_scoped_resource_reservation.hpp>
 
 /* Supervisor Calls. */
diff --git a/libraries/libmesosphere/include/mesosphere/kern_k_unsafe_memory.hpp b/libraries/libmesosphere/include/mesosphere/kern_k_unsafe_memory.hpp
new file mode 100644
index 000000000..713d240fd
--- /dev/null
+++ b/libraries/libmesosphere/include/mesosphere/kern_k_unsafe_memory.hpp
@@ -0,0 +1,78 @@
+/*
+ * 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 <mesosphere/kern_common.hpp>
+#include <mesosphere/kern_k_light_lock.hpp>
+
+namespace ams::kern {
+
+    class KUnsafeMemory {
+        private:
+            mutable KLightLock lock;
+            size_t limit_size;
+            size_t current_size;
+        public:
+            constexpr KUnsafeMemory() : lock(), limit_size(), current_size() { /* ... */ }
+
+            bool TryReserve(size_t size) {
+                MESOSPHERE_ASSERT_THIS();
+                KScopedLightLock lk(this->lock);
+
+                /* Test for overflow. */
+                if (this->current_size > this->current_size + size) {
+                    return false;
+                }
+
+                /* Test for limit allowance. */
+                if (this->current_size + size > this->limit_size) {
+                    return false;
+                }
+
+                /* Reserve the size. */
+                this->current_size += size;
+                return true;
+            }
+
+            void Release(size_t size) {
+                MESOSPHERE_ASSERT_THIS();
+                KScopedLightLock lk(this->lock);
+
+                MESOSPHERE_ABORT_UNLESS(this->current_size >= size);
+                this->current_size -= size;
+            }
+
+            size_t GetLimitSize() const {
+                MESOSPHERE_ASSERT_THIS();
+                KScopedLightLock lk(this->lock);
+                return this->limit_size;
+            }
+
+            size_t GetCurrentSize() const {
+                MESOSPHERE_ASSERT_THIS();
+                KScopedLightLock lk(this->lock);
+                return this->current_size;
+            }
+
+            Result SetLimitSize(size_t size) {
+                MESOSPHERE_ASSERT_THIS();
+                KScopedLightLock lk(this->lock);
+
+                R_UNLESS(size >= this->current_size, svc::ResultLimitReached());
+                this->limit_size = size;
+                return ResultSuccess();
+            }
+    };
+}
diff --git a/libraries/libmesosphere/include/mesosphere/kern_kernel.hpp b/libraries/libmesosphere/include/mesosphere/kern_kernel.hpp
index 5fba52000..4d4845240 100644
--- a/libraries/libmesosphere/include/mesosphere/kern_kernel.hpp
+++ b/libraries/libmesosphere/include/mesosphere/kern_kernel.hpp
@@ -35,6 +35,7 @@ namespace ams::kern {
     class KMemoryBlockSlabManager;
     class KBlockInfoManager;
     class KSynchronization;
+    class KUnsafeMemory;
 
 
 
@@ -72,6 +73,7 @@ namespace ams::kern {
             static KBlockInfoManager s_block_info_manager;
             static KSupervisorPageTable s_supervisor_page_table;
             static KSynchronization s_synchronization;
+            static KUnsafeMemory s_unsafe_memory;
             static KWorkerTaskManager s_worker_task_managers[KWorkerTaskManager::WorkerType_Count];
         private:
             static ALWAYS_INLINE KCoreLocalContext &GetCoreLocalContext() {
@@ -144,6 +146,10 @@ namespace ams::kern {
                 return s_synchronization;
             }
 
+            static ALWAYS_INLINE KUnsafeMemory &GetUnsafeMemory() {
+                return s_unsafe_memory;
+            }
+
             static ALWAYS_INLINE KWorkerTaskManager &GetWorkerTaskManager(KWorkerTaskManager::WorkerType type) {
                 MESOSPHERE_ASSERT(type <= KWorkerTaskManager::WorkerType_Count);
                 return s_worker_task_managers[type];
diff --git a/mesosphere/kernel/source/kern_kernel_instantiations.cpp b/mesosphere/kernel/source/kern_kernel_instantiations.cpp
index 33272a4f2..743dc5596 100644
--- a/mesosphere/kernel/source/kern_kernel_instantiations.cpp
+++ b/mesosphere/kernel/source/kern_kernel_instantiations.cpp
@@ -27,6 +27,7 @@ namespace ams::kern {
     KBlockInfoManager       Kernel::s_block_info_manager;
     KSupervisorPageTable    Kernel::s_supervisor_page_table;
     KSynchronization        Kernel::s_synchronization;
+    KUnsafeMemory           Kernel::s_unsafe_memory;
     KWorkerTaskManager      Kernel::s_worker_task_managers[KWorkerTaskManager::WorkerType_Count];
 
     namespace {