From 69c3bc705c34fd1f853d4c61fb5626b80587f5df Mon Sep 17 00:00:00 2001
From: Zephyron <zephyron@citron-emu.org>
Date: Fri, 5 Sep 2025 15:43:59 +1000
Subject: [PATCH] feat: implement missing kernel event handle and service
 function

- Implement CreateInterruptEvent SVC function to resolve panic
  - Add proper resource management with KScopedResourceReservation
  - Use regular KEvent as placeholder for interrupt events
  - Add proper cleanup with SCOPE_EXIT
  - Include debug logging for troubleshooting

- Implement GetLaunchRequiredVersionUpgrade in IApplicationFunctions service
  - Fix "Unknown / unimplemented function" error for command 210
  - Return event handle instead of boolean to match Nintendo Switch API
  - Use state_changed_event as placeholder until dedicated event is implemented
  - Add function declaration to header file

Tested with Hollow Knight: Silksong - successfully boots.

Signed-off-by: Zephyron <zephyron@citron-emu.org>
---
 .../hle/kernel/svc/svc_interrupt_event.cpp    | 40 ++++++++++++++++++-
 .../am/service/application_functions.cpp      | 11 ++++-
 .../am/service/application_functions.h        |  1 +
 3 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/src/core/hle/kernel/svc/svc_interrupt_event.cpp b/src/core/hle/kernel/svc/svc_interrupt_event.cpp
index 768b30a1f..07c02211b 100644
--- a/src/core/hle/kernel/svc/svc_interrupt_event.cpp
+++ b/src/core/hle/kernel/svc/svc_interrupt_event.cpp
@@ -1,6 +1,12 @@
 // SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include "common/logging/log.h"
+#include "common/scope_exit.h"
+#include "core/hle/kernel/k_event.h"
+#include "core/hle/kernel/k_process.h"
+#include "core/hle/kernel/k_scoped_resource_reservation.h"
 #include "core/hle/kernel/svc.h"
 #include "core/hle/kernel/svc_results.h"
 
@@ -8,8 +14,38 @@ namespace Kernel::Svc {
 
 Result CreateInterruptEvent(Core::System& system, Handle* out, int32_t interrupt_id,
                             InterruptType type) {
-    UNIMPLEMENTED();
-    R_THROW(ResultNotImplemented);
+    LOG_DEBUG(Kernel_SVC, "called, interrupt_id={}, type={}", interrupt_id, static_cast<u32>(type));
+
+    // Get the kernel reference and handle table.
+    auto& kernel = system.Kernel();
+    auto& handle_table = GetCurrentProcess(kernel).GetHandleTable();
+
+    // Reserve a new event from the process resource limit
+    KScopedResourceReservation event_reservation(GetCurrentProcessPointer(kernel),
+                                                 LimitableResource::EventCountMax);
+    R_UNLESS(event_reservation.Succeeded(), ResultLimitReached);
+
+    // Create a new event (for now, we'll use a regular event as interrupt events aren't fully implemented)
+    KEvent* event = KEvent::Create(kernel);
+    R_UNLESS(event != nullptr, ResultOutOfResource);
+
+    // Initialize the event.
+    event->Initialize(GetCurrentProcessPointer(kernel));
+
+    // Commit the thread reservation.
+    event_reservation.Commit();
+
+    // Ensure that we clean up the event (and its only references are handle table) on function end.
+    SCOPE_EXIT {
+        event->GetReadableEvent().Close();
+        event->Close();
+    };
+
+    // Register the event.
+    KEvent::Register(kernel, event);
+
+    // Add the readable event to the handle table.
+    R_RETURN(handle_table.Add(out, std::addressof(event->GetReadableEvent())));
 }
 
 Result CreateInterruptEvent64(Core::System& system, Handle* out_read_handle, int32_t interrupt_id,
diff --git a/src/core/hle/service/am/service/application_functions.cpp b/src/core/hle/service/am/service/application_functions.cpp
index fe4d250a3..0d005dec5 100644
--- a/src/core/hle/service/am/service/application_functions.cpp
+++ b/src/core/hle/service/am/service/application_functions.cpp
@@ -86,7 +86,7 @@ IApplicationFunctions::IApplicationFunctions(Core::System& system_, std::shared_
         {181, nullptr, "UpgradeLaunchRequiredVersion"},
         {190, nullptr, "SendServerMaintenanceOverlayNotification"},
         {200, nullptr, "GetLastApplicationExitReason"},
-        {210, nullptr, "GetLaunchRequiredVersionUpgrade"},
+        {210, D<&IApplicationFunctions::GetLaunchRequiredVersionUpgrade>, "GetLaunchRequiredVersionUpgrade"},
         {211, nullptr, "GetLaunchRequiredVersionUpgradeStatus"},
         {300, nullptr, "RequestToLaunchApplication"},
         {301, nullptr, "RequestToLaunchApplicationWithUserAndArguments"},
@@ -508,4 +508,13 @@ Result IApplicationFunctions::PrepareForJit() {
     R_SUCCEED();
 }
 
+Result IApplicationFunctions::GetLaunchRequiredVersionUpgrade(OutCopyHandle<Kernel::KReadableEvent> out_event) {
+    LOG_WARNING(Service_AM, "(STUBBED) called");
+
+    // TODO(ZEP): Add a dedicated launch_required_version_upgrade_event when implemented
+    *out_event = m_applet->state_changed_event.GetHandle();
+
+    R_SUCCEED();
+}
+
 } // namespace Service::AM
diff --git a/src/core/hle/service/am/service/application_functions.h b/src/core/hle/service/am/service/application_functions.h
index 10025a152..0da5e631b 100644
--- a/src/core/hle/service/am/service/application_functions.h
+++ b/src/core/hle/service/am/service/application_functions.h
@@ -77,6 +77,7 @@ private:
     Result GetNotificationStorageChannelEvent(OutCopyHandle<Kernel::KReadableEvent> out_event);
     Result GetHealthWarningDisappearedSystemEvent(OutCopyHandle<Kernel::KReadableEvent> out_event);
     Result PrepareForJit();
+    Result GetLaunchRequiredVersionUpgrade(OutCopyHandle<Kernel::KReadableEvent> out_event);
 
     const std::shared_ptr<Applet> m_applet;
 };