kern: add (and use) generic KSystemControlBase

libraries/libmesosphere/include/mesosphere/kern_select_system_control.hpp

@@ -15,6 +15,7 @@
  */
 #pragma once
 #include <mesosphere/kern_common.hpp>
+#include <mesosphere/kern_k_system_control_base.hpp>
 
 #ifdef ATMOSPHERE_BOARD_NINTENDO_NX
     #include <mesosphere/board/nintendo/nx/kern_k_system_control.hpp>
@@ -33,3 +34,18 @@
 #else
     #error "Unknown board for KSystemControl"
 #endif
+
+namespace ams::kern {
+
+    ALWAYS_INLINE u32 KSystemControlBase::ReadRegisterPrivileged(ams::svc::PhysicalAddress address) {
+        u32 v;
+        KSystemControl::ReadWriteRegisterPrivileged(std::addressof(v), address, 0x00000000u, 0);
+        return v;
+    }
+
+    ALWAYS_INLINE void KSystemControlBase::WriteRegisterPrivileged(ams::svc::PhysicalAddress address, u32 value) {
+        u32 v;
+        KSystemControl::ReadWriteRegisterPrivileged(std::addressof(v), address, 0xFFFFFFFFu, value);
+    }
+
+}