kern: implement KThreadLocalPage

libraries/libmesosphere/include/mesosphere/kern_k_page_buffer.hpp

@@ -0,0 +1,42 @@
+/*
+ * 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_slab_helpers.hpp>
+#include <mesosphere/kern_k_memory_layout.hpp>
+
+namespace ams::kern {
+
+    class KPageBuffer : public KSlabAllocated<KPageBuffer> {
+        private:
+            alignas(PageSize) u8 buffer[PageSize];
+        public:
+            KPageBuffer() {
+                std::memset(buffer, 0, sizeof(buffer));
+            }
+
+            static ALWAYS_INLINE KPageBuffer *FromPhysicalAddress(KPhysicalAddress phys_addr) {
+                const KVirtualAddress virt_addr = KMemoryLayout::GetLinearVirtualAddress(phys_addr);
+
+                MESOSPHERE_ASSERT(util::IsAligned(GetInteger(phys_addr), PageSize));
+                MESOSPHERE_ASSERT(util::IsAligned(GetInteger(virt_addr), PageSize));
+
+                return GetPointer<KPageBuffer>(virt_addr);
+            }
+    };
+    static_assert(sizeof(KPageBuffer)  == PageSize);
+    static_assert(alignof(KPageBuffer) == PageSize);
+
+}