From 7e29ba6fba9d509ef8fcd1a905367a5ece529076 Mon Sep 17 00:00:00 2001
From: notaxeltv <notaxeltv@gmail.com>
Date: Wed, 14 Oct 2026 21:55:33 +0200
Subject: [PATCH] feat(libSceLoginService): let PPSA34015 load without a
 missing module

FC 27 stops on Windows with Failed to load module / error 126 because this PRX is absent. Export Initialize and Terminate as no-ops and keep RequestDevices throwing until the buffer layout is known.

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 .../prx/libSceLoginService/CMakeLists.txt     | 15 +++++++++
 core/libs/prx/libSceLoginService/Export.cpp   | 21 +++++++++++++
 core/libs/tests/GuestLoginService.cpp         | 31 +++++++++++++++++++
 docs/dev/debt/libSceLoginService.md           |  9 ++++++
 4 files changed, 76 insertions(+)
 create mode 100644 core/libs/prx/libSceLoginService/CMakeLists.txt
 create mode 100644 core/libs/prx/libSceLoginService/Export.cpp
 create mode 100644 core/libs/tests/GuestLoginService.cpp
 create mode 100644 docs/dev/debt/libSceLoginService.md

diff --git a/core/libs/prx/libSceLoginService/CMakeLists.txt b/core/libs/prx/libSceLoginService/CMakeLists.txt
new file mode 100644
index 0000000000..5993f09b49
--- /dev/null
+++ b/core/libs/prx/libSceLoginService/CMakeLists.txt
@@ -0,0 +1,15 @@
+add_library(libSceLoginService SHARED EXCLUDE_FROM_ALL Export.cpp)
+target_include_directories(libSceLoginService PRIVATE ${LIBS_INCLUDE_DIR})
+configure_windows_unwind(libSceLoginService)
+
+if(BUILD_TESTING)
+    add_test_executable(guest_login_service_tests ${LIBS_INCLUDE_DIR}/tests/GuestLoginService.cpp)
+    target_include_directories(guest_login_service_tests PRIVATE ${LIBS_INCLUDE_DIR})
+    target_link_libraries(guest_login_service_tests PRIVATE libSceLoginService libc)
+    configure_windows_unwind(guest_login_service_tests)
+    add_test(NAME guest_login_service COMMAND guest_login_service_tests)
+    if(WIN32)
+        set_tests_properties(guest_login_service PROPERTIES ENVIRONMENT_MODIFICATION
+            "PATH=path_list_prepend:$<TARGET_FILE_DIR:libSceLoginService>")
+    endif()
+endif()
diff --git a/core/libs/prx/libSceLoginService/Export.cpp b/core/libs/prx/libSceLoginService/Export.cpp
new file mode 100644
index 0000000000..43a1b1dcdf
--- /dev/null
+++ b/core/libs/prx/libSceLoginService/Export.cpp
@@ -0,0 +1,21 @@
+#include <cstdint>
+#include "SceTypes.hpp"
+#include "prx/libc/include/General.hpp"
+
+extern "C" {
+
+int APS5_VABI sceLoginServiceInitialize(void) {
+    return 0;
+}
+
+int APS5_VABI sceLoginServiceTerminate(void) {
+    return 0;
+}
+
+int APS5_VABI sceLoginServiceRequestDevices(void* param) {
+    (void)param;
+    NotImplemented_nid_no_patch(__func__);
+    return 0;
+}
+
+}
diff --git a/core/libs/tests/GuestLoginService.cpp b/core/libs/tests/GuestLoginService.cpp
new file mode 100644
index 0000000000..a1fa20d143
--- /dev/null
+++ b/core/libs/tests/GuestLoginService.cpp
@@ -0,0 +1,31 @@
+#include "prx/libc/include/general/VabiMacros.hpp"
+
+#include <cstdio>
+#include <cstdlib>
+#include <stdexcept>
+#include <string>
+
+extern "C" {
+int APS5_VABI sceLoginServiceInitialize(void);
+int APS5_VABI sceLoginServiceTerminate(void);
+int APS5_VABI sceLoginServiceRequestDevices(void* param);
+}
+
+static void Require(bool value) {
+    if (!value) std::abort();
+}
+
+int main() {
+    Require(sceLoginServiceInitialize() == 0);
+    Require(sceLoginServiceTerminate() == 0);
+    unsigned char buffer[0x80]{};
+    try {
+        sceLoginServiceRequestDevices(buffer);
+    } catch (const std::runtime_error& error) {
+        if (std::string(error.what()) == "sceLoginServiceRequestDevices not implemented") return 0;
+        std::fprintf(stderr, "sceLoginServiceRequestDevices threw: %s\n", error.what());
+        return 1;
+    }
+    std::fprintf(stderr, "sceLoginServiceRequestDevices returned instead of reporting that it is not implemented\n");
+    return 1;
+}
diff --git a/docs/dev/debt/libSceLoginService.md b/docs/dev/debt/libSceLoginService.md
new file mode 100644
index 0000000000..f33713e90d
--- /dev/null
+++ b/docs/dev/debt/libSceLoginService.md
@@ -0,0 +1,9 @@
+# libSceLoginService technical debt
+
+### Silent stubs
+
+- [sceLoginServiceInitialize, sceLoginServiceTerminate](../../../core/libs/prx/libSceLoginService/Export.cpp) (libSceLoginService) - return success and keep no login-service state: AnyPS5 has no PSN login service. EA SPORTS FC 27 (PPSA34015) loads the module with `sceSysmoduleLoadModule(0xe3)` and calls `sceLoginServiceInitialize` with no arguments; a missing `libSceLoginService.prx` stops Windows start-up with `Failed to load module` / `GetLastError: 126`
+
+### Unknown function info
+
+- [sceLoginServiceRequestDevices](../../../core/libs/prx/libSceLoginService/Export.cpp) (libSceLoginService) - PPSA34015 passes one pointer to a stack buffer (`lea rdi, [rbp-0x80]`) then calls `sceLoginServiceTerminate`. The buffer layout, other arguments and console errors are unknown, so every call throws without reading or writing caller memory