Implement plugin loader Mode3 mem strategy (#7)

src/core/loader/loader.h

@@ -117,6 +117,14 @@ public:
         return std::make_pair(0x2, ResultStatus::Success);
     }
 
+    /**
+     * Forces the application memory mode to the specified value,
+     * overriding the memory mode specified in the metadata.
+     */
+    void SetKernelMemoryModeOverride(Kernel::MemoryMode mem_override) {
+        memory_mode_override = mem_override;
+    }
+
     /**
      * Loads the memory mode that this application needs.
      * This function defaults to Dev1 (96MB allocated to the application) if it can't read the
@@ -124,6 +132,9 @@ public:
      * @returns A pair with the optional memory mode, and the status.
      */
     virtual std::pair<std::optional<Kernel::MemoryMode>, ResultStatus> LoadKernelMemoryMode() {
+        if (memory_mode_override.has_value()) {
+            return std::make_pair(*memory_mode_override, ResultStatus::Success);
+        }
         // 96MB allocated to the application.
         return std::make_pair(Kernel::MemoryMode::Dev1, ResultStatus::Success);
     }
@@ -257,6 +268,7 @@ protected:
     Core::System& system;
     FileUtil::IOFile file;
     bool is_loaded = false;
+    std::optional<Kernel::MemoryMode> memory_mode_override = std::nullopt;
 };
 
 /**

src/core/loader/ncch.cpp

@@ -69,6 +69,9 @@ std::pair<std::optional<Kernel::MemoryMode>, ResultStatus> AppLoader_NCCH::LoadK
             return std::make_pair(std::nullopt, res);
         }
     }
+    if (memory_mode_override.has_value()) {
+        return std::make_pair(memory_mode_override, ResultStatus::Success);
+    }
 
     // Provide the memory mode from the exheader.
     auto& ncch_caps = overlay_ncch->exheader_header.arm11_system_local_caps;
@@ -159,7 +162,7 @@ ResultStatus AppLoader_NCCH::LoadExec(std::shared_ptr<Kernel::Process>& process)
         // APPLICATION. See:
         // https://github.com/LumaTeam/Luma3DS/blob/e2778a45/sysmodules/pm/source/launch.c#L237
         auto& ncch_caps = overlay_ncch->exheader_header.arm11_system_local_caps;
-        const auto o3ds_mode = static_cast<Kernel::MemoryMode>(ncch_caps.system_mode.Value());
+        const auto o3ds_mode = *LoadKernelMemoryMode().first;
         const auto n3ds_mode = static_cast<Kernel::New3dsMemoryMode>(ncch_caps.n3ds_mode);
         const bool is_new_3ds = Settings::values.is_new_3ds.GetValue();
         if (is_new_3ds && n3ds_mode == Kernel::New3dsMemoryMode::Legacy &&