exosphere: allow memory mode to be used on retail

config_templates/exosphere.ini

@@ -15,6 +15,13 @@
 #  Desc: Controls whether userland has access to the PMU registers.
 #  NOTE: It is unknown what effects this has on official code.
 
+# Key: enable_mem_mode, default: 0.
+#  Desc: Controls whether boot config memory mode is taken into account
+#   for retail units. This does not affect development units.
+#  NOTE: On retail units max ram size is capped to 4GB.
+#   Enabling this will use the boot config memory mode parameter,
+#   which by default is auto and size gets set based on physical size.
+
 # Key: blank_prodinfo_sysmmc, default: 0.
 #  Desc: Controls whether PRODINFO should be blanked in sysmmc.
 #   This will cause the system to see dummied out keys and
@@ -51,6 +58,7 @@ debugmode=1
 debugmode_user=0
 disable_user_exception_handlers=0
 enable_user_pmu_access=0
+enable_mem_mode=0
 blank_prodinfo_sysmmc=0
 blank_prodinfo_emummc=0
 allow_writing_to_cal_sysmmc=0

exosphere/program/source/smc/secmon_smc_info.cpp

@@ -132,10 +132,13 @@ namespace ams::secmon::smc {
         }
 
         u32 GetMemoryMode() {
-            /* Unless development function is enabled, we're 4 GB. */
+            /* Unless development function or forced boot config memory size is enabled, we're 4 GB. */
             u32 memory_mode = pkg1::MemoryMode_4GB;
 
-            if (const auto &bcd = GetBootConfig().data; bcd.IsDevelopmentFunctionEnabled()) {
+            const auto &bcd = GetBootConfig().data;
+            const auto &sc  = GetSecmonConfiguration(); /* Exosphere extensions */
+
+            if (bcd.IsDevelopmentFunctionEnabled() || sc.IsBootConfigMemoryModeEnabled()) {
                 memory_mode = GetMemoryMode(bcd.GetMemoryMode());
             }
 
@@ -146,17 +149,19 @@ namespace ams::secmon::smc {
             pkg1::MemorySize memory_size = pkg1::MemorySize_4GB;
             util::BitPack32 value = {};
 
-            if (const auto &bcd = GetBootConfig().data; bcd.IsDevelopmentFunctionEnabled()) {
+            const auto &bcd = GetBootConfig().data;
-                memory_size = GetMemorySize(GetMemoryMode(bcd.GetMemoryMode()));
+            const auto &sc  = GetSecmonConfiguration(); /* Exosphere extensions */
 
+            if (bcd.IsDevelopmentFunctionEnabled()) {
                 value.Set<KernelConfiguration::Flags1>(bcd.GetKernelFlags1());
                 value.Set<KernelConfiguration::Flags0>(bcd.GetKernelFlags0());
             }
 
-            value.Set<KernelConfiguration::PhysicalMemorySize>(memory_size);
+            if (bcd.IsDevelopmentFunctionEnabled() || sc.IsBootConfigMemoryModeEnabled()) {
+                memory_size = GetMemorySize(GetMemoryMode(bcd.GetMemoryMode()));
+            }
 
-            /* Exosphere extensions. */
+            value.Set<KernelConfiguration::PhysicalMemorySize>(memory_size);
-            const auto &sc = GetSecmonConfiguration();
 
             if (!sc.DisableUserModeExceptionHandlers()) {
                 value.Set<KernelConfiguration::EnableUserExceptionHandlers>(true);

fusee/program/source/fusee_setup_horizon.cpp

@@ -543,6 +543,12 @@ namespace ams::nxboot {
                                 } else {
                                     storage_ctx.flags[0] &= ~secmon::SecureMonitorConfigurationFlag_EnableUserModePerformanceCounterAccess;
                                 }
+                            } else if (std::strcmp(entry.key, "enable_mem_mode") == 0) {
+                                if (entry.value[0] == '1') {
+                                    storage_ctx.flags[0] |= secmon::SecureMonitorConfigurationFlag_BootConfigMemoryModeEnabled;
+                                } else {
+                                    storage_ctx.flags[0] &= ~secmon::SecureMonitorConfigurationFlag_BootConfigMemoryModeEnabled;
+                                }
                             } else if (std::strcmp(entry.key, "blank_prodinfo_sysmmc") == 0) {
                                 if (!emummc_enabled) {
                                     if (entry.value[0] == '1') {

libraries/libexosphere/include/exosphere/secmon/secmon_monitor_context.hpp

@@ -30,6 +30,7 @@ namespace ams::secmon {
         SecureMonitorConfigurationFlag_ShouldUseBlankCalibrationBinary        = (1u << 5),
         SecureMonitorConfigurationFlag_AllowWritingToCalibrationBinarySysmmc  = (1u << 6),
         SecureMonitorConfigurationFlag_ForceEnableUsb30                       = (1u << 7),
+        SecureMonitorConfigurationFlag_BootConfigMemoryModeEnabled            = (1u << 8),
 
         SecureMonitorConfigurationFlag_Default = SecureMonitorConfigurationFlag_IsDevelopmentFunctionEnabledForKernel,
     };
@@ -103,6 +104,7 @@ namespace ams::secmon {
         constexpr bool ShouldUseBlankCalibrationBinary()        const { return (this->flags[0] & SecureMonitorConfigurationFlag_ShouldUseBlankCalibrationBinary)        != 0; }
         constexpr bool AllowWritingToCalibrationBinarySysmmc()  const { return (this->flags[0] & SecureMonitorConfigurationFlag_AllowWritingToCalibrationBinarySysmmc)  != 0; }
         constexpr bool IsUsb30ForceEnabled()                    const { return (this->flags[0] & SecureMonitorConfigurationFlag_ForceEnableUsb30)                       != 0; }
+        constexpr bool IsBootConfigMemoryModeEnabled()          const { return (this->flags[0] & SecureMonitorConfigurationFlag_BootConfigMemoryModeEnabled)            != 0; }
 
         constexpr bool IsDevelopmentFunctionEnabled(bool for_kern) const { return for_kern ? this->IsDevelopmentFunctionEnabledForKernel() : this->IsDevelopmentFunctionEnabledForUser(); }
     };