fix(libkernel): answer sceKernelGetPageTableStats

core/libs/prx/libkernel/DirectMemory/Export.cpp

@@ -388,11 +388,12 @@ int APS5_VABI sceKernelClearVirtualRangeName(const void* addr, uint64_t len) {
 }
 
 int APS5_VABI sceKernelGetPageTableStats(int* cpu_total, int* cpu_available, int* gpu_total, int* gpu_available) {
- (void)cpu_total;
- (void)cpu_available;
- (void)gpu_total;
- (void)gpu_available;
- NotImplemented_nid_no_patch(__func__);
+ if (!cpu_total || !cpu_available || !gpu_total || !gpu_available) return SCE_KERNEL_ERROR_EFAULT;
+ constexpr int pageTableEntries = static_cast<int>((4ull << 30) / (2ull << 20));
+ *cpu_total = pageTableEntries;
+ *cpu_available = pageTableEntries;
+ *gpu_total = pageTableEntries;
+ *gpu_available = pageTableEntries;
  return 0;
 }
 

core/libs/tests/GuestMemory.cpp

@@ -58,6 +58,7 @@ int APS5_VABI sceKernelMemoryPoolBatch(const KernelMemoryPoolBatchEntry*, int, i
 int APS5_VABI sceKernelVirtualQuery(const void*, int, VirtualQueryInfo*, std::uint64_t);
 int APS5_VABI sceKernelSetVirtualRangeName(const void*, std::uint64_t, const char*);
 int APS5_VABI sceKernelClearVirtualRangeName(const void*, std::uint64_t);
+int APS5_VABI sceKernelGetPageTableStats(int*, int*, int*, int*);
 int APS5_VABI sceKernelAllocateDirectMemory(std::int64_t, std::int64_t, std::size_t, std::size_t, int, std::int64_t*);
 int APS5_VABI sceKernelMapDirectMemory(void**, std::size_t, int, int, std::int64_t, std::size_t);
 int APS5_VABI sceKernelEnableDmemAliasing();
@@ -113,6 +114,18 @@ static void CheckReleaseFlexibleMemory() {
     Require(sceKernelMunmap(again, length) == 0);
 }
 
+static void CheckPageTableStats() {
+    int cpuTotal = -1, cpuAvailable = -1, gpuTotal = -1, gpuAvailable = -1;
+    Require(sceKernelGetPageTableStats(&cpuTotal, &cpuAvailable, &gpuTotal, &gpuAvailable) == 0);
+    Require(cpuTotal > 0 && gpuTotal > 0);
+    Require(cpuAvailable >= 0 && cpuAvailable <= cpuTotal);
+    Require(gpuAvailable >= 0 && gpuAvailable <= gpuTotal);
+    Require(sceKernelGetPageTableStats(nullptr, &cpuAvailable, &gpuTotal, &gpuAvailable) == SCE_KERNEL_ERROR_EFAULT);
+    Require(sceKernelGetPageTableStats(&cpuTotal, nullptr, &gpuTotal, &gpuAvailable) == SCE_KERNEL_ERROR_EFAULT);
+    Require(sceKernelGetPageTableStats(&cpuTotal, &cpuAvailable, nullptr, &gpuAvailable) == SCE_KERNEL_ERROR_EFAULT);
+    Require(sceKernelGetPageTableStats(&cpuTotal, &cpuAvailable, &gpuTotal, nullptr) == SCE_KERNEL_ERROR_EFAULT);
+}
+
 static void CheckNamedAndHintedMappings() {
     constexpr std::size_t length = 0x10000;
     void* first = nullptr;
@@ -1871,6 +1884,7 @@ int main() {
     CheckReleaseFlexibleMemory();
     CheckVirtualQueryPartialMunmap();
     CheckMunmapOverUnmappedPages();
+    CheckPageTableStats();
     CheckNamedAndHintedMappings();
     CheckInternalNamedFlexibleMapping();
     CheckGuestModuleUsesFlexibleMemory();

docs/dev/debt/libkernel.md

@@ -155,3 +155,4 @@
 - [pthread_spin_init, pthread_spin_destroy, pthread_spin_lock, pthread_spin_trylock, pthread_spin_unlock](../../../core/libs/prx/libkernel/Pthread/Posix/Spinlock.cpp) (libkernel) follow FreeBSD 11.4 libthr [`thr_pspinlock.c`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/lib/libthr/thread/thr_pspinlock.c) and the owner checks of its [`thr_umtx.h`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/lib/libthr/thread/thr_umtx.h#L80-L175), unverified on the console: `EINVAL` for a null or destroyed lock and a `pshared` other than 0 or 1, `EBUSY` from `trylock` while any thread holds it, `EPERM` from `unlock` by a thread that does not hold it. `PTHREAD_PROCESS_SHARED` allocates a private lock, as guest code runs in one process. libthr spins forever when the holder locks again; here that call throws
 - [pthread_cond_reltimedwait_np](../../../core/libs/prx/libkernel/Pthread/Posix/Cond.cpp) (libkernel) takes `(cond, mutex, usec)`, a relative timeout in microseconds, and is `scePthreadCondTimedwait` with POSIX error numbers. FreeBSD 11.4 has no such function; the signature comes only from shadPS4, which registers one function for this NID and for `scePthreadCondTimedwait` ([`condvar.cpp`](https://github.com/shadps4-emu/shadPS4/blob/3a9f57265d28975658f1ca941daa5c879c7a74bd/src/core/libraries/kernel/threads/condvar.cpp#L229-L234)). shadPS4 reads a 64-bit count; here it is the 32-bit `SceKernelUseconds` of the SCE twin, as for `sem_reltimedwait_np`. Unverified on the console
 - [sysctl kern.arandom](../../../core/libs/prx/libkernel/System/src/SystemConfiguration.cpp) (libkernel) serves FreeBSD 11's MIB {1, 37} (CTL_KERN, KERN_ARANDOM) and the "kern.arandom" sysctlbyname lookup through std::random_device, returning min(*oldLength, 256) random bytes. Following FreeBSD's sysctl_kern_arnd, a null buffer reports min(*oldLength, 256) without writing, a null length returns 0 without writing, and requests with a new value return EPERM (1) as the node is read-only. Cryptographic quality depends on the host's random device implementation.
+- [sceKernelGetPageTableStats](../../../core/libs/prx/libkernel/DirectMemory/Export.cpp) (libkernel) - reports 2048 page-table entries on each side (a 4 GiB pool of 2 MiB entries, the constants of [KytyPS5](https://github.com/KytyPS5/KytyPS5/blob/main/src/kernel/memory.cpp)) and all of them available: no entries are counted as used, so a title never sees page-table pressure. KytyPS5 counts the 2 MiB entries of the committed CPU- or GPU-accessible ranges as used, which this port does not do. The four `int*` arguments follow OpenOrbis' `libkernel.h`, the Orbital type database and SharpProspero; a null pointer returns `SCE_KERNEL_ERROR_EFAULT` as in KytyPS5. None of the values is measured on a console. PPSA30601 (Resonance) calls it during start-up