Kernel/Loader: Grab the system mode from the NCCH ExHeader.

3dsx and elf files default to system mode 2 (96MB allocated to the application).

This allows Home Menu to boot without modifications.
Closes #1849

3 files changed, 17 insertions, 16 deletions

diff --git a/src/core/loader/loader.h b/src/core/loader/loader.h
index e62f77b9c..5e3d46638 100644
--- a/src/core/loader/loader.h
+++ b/src/core/loader/loader.h
@@ -9,6 +9,7 @@
 #include <memory>
 #include <string>
 #include <vector>
+#include <boost/optional.hpp>
 #include "common/common_types.h"
 #include "common/file_util.h"
 
@@ -97,13 +98,13 @@ public:
 
     /**
      * Loads the system mode that this application needs.
-     * This function defaults to 2 (96MB allocated to the application) if it can't read the information.
-     * @param system_mode Out variable where the system mode will be stored.
-     * @returns ResultStatus result of the operation
+     * This function defaults to 2 (96MB allocated to the application) if it can't read the
+     * information.
+     * @returns Optional with the kernel system mode
      */
-    virtual ResultStatus LoadKernelSystemMode(u32& system_mode) {
-        system_mode = 2; // 96MB allocated to the application.
-        return ResultStatus::Success;
+    virtual boost::optional<u32> LoadKernelSystemMode() {
+        // 96MB allocated to the application.
+        return 2;
     }
 
     /**
diff --git a/src/core/loader/ncch.cpp b/src/core/loader/ncch.cpp
index 6fbaf4036..d4be61e0e 100644
--- a/src/core/loader/ncch.cpp
+++ b/src/core/loader/ncch.cpp
@@ -117,12 +117,12 @@ FileType AppLoader_NCCH::IdentifyType(FileUtil::IOFile& file) {
     return FileType::Error;
 }
 
-ResultStatus AppLoader_NCCH::LoadKernelSystemMode(u32& memory_type) {
-    ResultStatus result = LoadExeFS();
-    if (result != ResultStatus::Success)
-        return result;
-    memory_type = exheader_header.arm11_system_local_caps.system_mode;
-    return ResultStatus::Success;
+boost::optional<u32> AppLoader_NCCH::LoadKernelSystemMode() {
+    if (!is_loaded) {
+        if (LoadExeFS() != ResultStatus::Success)
+            return boost::none;
+    }
+    return exheader_header.arm11_system_local_caps.system_mode.Value();
 }
 
 ResultStatus AppLoader_NCCH::LoadExec() {
@@ -285,7 +285,8 @@ ResultStatus AppLoader_NCCH::LoadExeFS() {
     LOG_DEBUG(Loader, "Core version:                %d", core_version);
     LOG_DEBUG(Loader, "Thread priority:             0x%X", priority);
     LOG_DEBUG(Loader, "Resource limit category:     %d", resource_limit_category);
-    LOG_DEBUG(Loader, "System Mode:                 %d", exheader_header.arm11_system_local_caps.system_mode);
+    LOG_DEBUG(Loader, "System Mode:                 %d",
+              exheader_header.arm11_system_local_caps.system_mode);
 
     if (exheader_header.arm11_system_local_caps.program_id != ncch_header.program_id) {
         LOG_ERROR(Loader, "ExHeader Program ID mismatch: the ROM is probably encrypted.");
diff --git a/src/core/loader/ncch.h b/src/core/loader/ncch.h
index 63947c28e..bcf3ae6e3 100644
--- a/src/core/loader/ncch.h
+++ b/src/core/loader/ncch.h
@@ -187,10 +187,9 @@ public:
 
     /**
      * Loads the Exheader and returns the system mode for this application.
-     * @param system_mode Out variable where the system mode will be stored.
-     * @return ResultStatus result of the operation
+     * @return Optional with the kernel system mode
      */
-    ResultStatus LoadKernelSystemMode(u32& system_mode);
+    boost::optional<u32> LoadKernelSystemMode();
 
     /**
      * Get the code (typically .code section) of the application