From 0e315cbd8fe869e98b94f8862143ee5546cb4864 Mon Sep 17 00:00:00 2001
From: Stephen Miller <56742918+StevenMiller123@users.noreply.github.com>
Date: Sun, 9 Mar 2025 08:12:05 -0500
Subject: [PATCH] sceKernelReleaseDirectMemory fix (#2623)

* Fix error return on sceKernelMunmap

FreeBSD docs state that len <= 0 is a EINVAL return.

* Early return on ReleaseDirectMemory with len = 0

Calls to these two functions with len = 0 cause an assert in CarveDmemArea. Since there's no memory to release, an early return should be safe here.

* Remove check for negative length in munmap

Addresses review comment
---
 src/core/libraries/kernel/memory.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/core/libraries/kernel/memory.cpp b/src/core/libraries/kernel/memory.cpp
index 82c5115f1..7b3ac5646 100644
--- a/src/core/libraries/kernel/memory.cpp
+++ b/src/core/libraries/kernel/memory.cpp
@@ -79,6 +79,9 @@ s32 PS4_SYSV_ABI sceKernelAllocateMainDirectMemory(size_t len, size_t alignment,
 }
 
 s32 PS4_SYSV_ABI sceKernelCheckedReleaseDirectMemory(u64 start, size_t len) {
+    if (len == 0) {
+        return ORBIS_OK;
+    }
     LOG_INFO(Kernel_Vmm, "called start = {:#x}, len = {:#x}", start, len);
     auto* memory = Core::Memory::Instance();
     memory->Free(start, len);
@@ -86,6 +89,9 @@ s32 PS4_SYSV_ABI sceKernelCheckedReleaseDirectMemory(u64 start, size_t len) {
 }
 
 s32 PS4_SYSV_ABI sceKernelReleaseDirectMemory(u64 start, size_t len) {
+    if (len == 0) {
+        return ORBIS_OK;
+    }
     auto* memory = Core::Memory::Instance();
     memory->Free(start, len);
     return ORBIS_OK;
@@ -507,7 +513,7 @@ s32 PS4_SYSV_ABI sceKernelConfiguredFlexibleMemorySize(u64* sizeOut) {
 int PS4_SYSV_ABI sceKernelMunmap(void* addr, size_t len) {
     LOG_INFO(Kernel_Vmm, "addr = {}, len = {:#x}", fmt::ptr(addr), len);
     if (len == 0) {
-        return ORBIS_OK;
+        return ORBIS_KERNEL_ERROR_EINVAL;
     }
     auto* memory = Core::Memory::Instance();
     return memory->UnmapMemory(std::bit_cast<VAddr>(addr), len);