From 2c782721851ba4bb66ad5964944c4f6ee6f990f7 Mon Sep 17 00:00:00 2001
From: Stephen Miller <56742918+StevenMiller123@users.noreply.github.com>
Date: Tue, 3 Jun 2025 00:02:51 -0500
Subject: [PATCH] Emulate libSceGnmDriver's init behavior (#3024)

This time, perform it after the LoadSharedLibraries call, which places it after the various init memory mappings GFD engine titles perform.
---
 src/core/linker.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/core/linker.cpp b/src/core/linker.cpp
index 3e6d8c22e..c50b03a8f 100644
--- a/src/core/linker.cpp
+++ b/src/core/linker.cpp
@@ -117,6 +117,18 @@ void Linker::Execute(const std::vector<std::string> args) {
         Common::SetCurrentThreadName("GAME_MainThread");
         LoadSharedLibraries();
 
+        // Simulate libSceGnmDriver initialization, which maps a chunk of direct memory.
+        // Some games fail without accurately emulating this behavior.
+        s64 phys_addr{};
+        s32 result = Libraries::Kernel::sceKernelAllocateDirectMemory(
+            0, Libraries::Kernel::sceKernelGetDirectMemorySize(), 0x10000, 0x10000, 3, &phys_addr);
+        if (result == 0) {
+            void* addr{reinterpret_cast<void*>(0xfe0000000)};
+            result = Libraries::Kernel::sceKernelMapNamedDirectMemory(
+                &addr, 0x10000, 0x13, 0, phys_addr, 0x10000, "SceGnmDriver");
+        }
+        ASSERT_MSG(result == 0, "Unable to emulate libSceGnmDriver initialization");
+
         // Start main module.
         EntryParams params{};
         params.argc = 1;