Module start/stop threads: 0x1000 default stack for kernel modules

modulemgr only defaults a module_start/module_stop thread's stack to 0x40000
for user modules. Kernel modules get 0x1000. We gave every
module 0x40000, which mostly cost kernel memory when booting the VSH.

User modules, and so games, are unaffected.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Core/HLE/sceKernelModule.cpp

@@ -1230,11 +1230,8 @@ static std::string ResolveVshModelModule(const char *path) {
 
 static void LoadAndStartVshKernelModules() {
 	// These 11 are small, simple kernel drivers (a few KB to ~100KB of code each) that don't
-	// declare their own smaller module_start_thread_stacksize, so __KernelStartModule's
-	// generic 0x40000 (256KB) default applies to every one of them. 11 of
-	// them at 256KB each (2.75MB) is a lot relative to the 4MB kernel memory pool.
-	//
-	// If we run out of kernel memory for some reason, we can force these to a smaller stack size.
+	// declare their own module_start_thread_stacksize, so each start thread gets the kernel
+	// module default of 0x1000.
 	static const char *const vshSmallKernelModulePaths[] = {
 		"flash0:/kd/dmacman.prx",
 		"flash0:/kd/systimer.prx",
@@ -1248,11 +1245,6 @@ static void LoadAndStartVshKernelModules() {
 		"flash0:/kd/wlanfirm_01g.prx",
 		"flash0:/kd/utility.prx",
 	};
-	/*
-	SceKernelSMOption smallStackOption{};
-	smallStackOption.size = sizeof(smallStackOption);
-	smallStackOption.stacksize = 0x40000;
-	*/
 	for (const char *path : vshSmallKernelModulePaths) {
 		const std::string resolved = ResolveVshModelModule(path);
 		if (!pspFileSystem.GetFileInfo(resolved).exists) {
@@ -2558,6 +2550,12 @@ static u32 sceKernelLoadModuleNpDrm(const char *name, u32 flags, u32 optionAddr)
 	return sceKernelLoadModule(name, flags, optionAddr);
 }
 
+// Stack size of a module_start/module_stop thread when neither the option nor the module's
+// thread parameter export gives one: 0x40000 for a user module, 0x1000 for a kernel module.
+static u32 ModuleThreadDefaultStackSize(const PSPModule *module) {
+	return (module->nm.attribute & 0x1000) != 0 ? 0x1000 : 0x40000;
+}
+
 int __KernelStartModule(SceUID moduleId, u32 argsize, u32 argAddr, u32 returnValueAddr, SceKernelSMOption *smoption, bool *needsWait) {
 	if (needsWait) {
 		*needsWait = false;
@@ -2570,7 +2568,7 @@ int __KernelStartModule(SceUID moduleId, u32 argsize, u32 argAddr, u32 returnVal
 	}
 
 	u32 priority = 0x20;
-	u32 stacksize = 0x40000;
+	u32 stacksize = ModuleThreadDefaultStackSize(module);
 	int attribute = module->nm.attribute;
 	u32 entryAddr = module->nm.entry_addr;
 
@@ -2645,7 +2643,6 @@ u32 sceKernelStartModule(u32 moduleId, u32 argsize, u32 argAddr, u32 returnValue
 static u32 sceKernelStopModule(u32 moduleId, u32 argSize, u32 argAddr, u32 returnValueAddr, u32 optionAddr)
 {
 	u32 priority = 0x20;
-	u32 stacksize = 0x40000;
 	u32 attr = 0;
 
 	// TODO: In a lot of cases (even for errors), this should resched.  Needs testing.
@@ -2667,6 +2664,7 @@ static u32 sceKernelStopModule(u32 moduleId, u32 argSize, u32 argAddr, u32 retur
 	}
 
 	u32 stopFunc = module->nm.module_stop_func;
+	u32 stacksize = ModuleThreadDefaultStackSize(module);
 	if (module->nm.module_stop_thread_priority != 0)
 		priority = module->nm.module_stop_thread_priority;
 	if (module->nm.module_stop_thread_stacksize != 0)
@@ -2734,7 +2732,6 @@ u32 __KernelStopUnloadSelfModuleWithOrWithoutStatus(u32 exitCode, u32 argSize, u
 		}
 		SceUID moduleID = __KernelGetCurThreadModuleId();
 		u32 priority = 0x20;
-		u32 stacksize = 0x40000;
 		u32 attr = 0;
 		// TODO: In a lot of cases (even for errors), this should resched.  Needs testing.
 
@@ -2749,6 +2746,7 @@ u32 __KernelStopUnloadSelfModuleWithOrWithoutStatus(u32 exitCode, u32 argSize, u
 		}
 
 		u32 stopFunc = module->nm.module_stop_func;
+		u32 stacksize = ModuleThreadDefaultStackSize(module);
 		if (module->nm.module_stop_thread_priority != 0)
 			priority = module->nm.module_stop_thread_priority;
 		if (module->nm.module_stop_thread_stacksize != 0)