[PR #3859] [MERGED] libkernel: Implement sceKernelEnableDmemAliasing, proper mapping type checks in posix_mmap #3763

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opened 2026-02-27 22:04:53 +03:00 by kerem · 0 comments

kerem commented

2026-02-27 22:04:53 +03:00

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📋 Pull Request Information

Original PR: https://github.com/shadps4-emu/shadPS4/pull/3859
Author: @StevenMiller123
Created: 12/7/2025
Status: ✅ Merged
Merged: 12/8/2025
Merged by: @georgemoralis

Base: main ← Head: quick-mem-fixes

📝 Commits (5)

0acd69d Basic handling for MAP_VOID, MAP_STACK, and MAP_ANON in mmap.
1bbb3a6 Update memory.cpp
110461f Update memory.cpp
9cdd547 Dmem aliasing check
ea426a8 Oops

📊 Changes

2 files changed (+43 additions, -5 deletions)

View changed files

📝 src/core/libraries/kernel/memory.cpp (+40 -5)
📝 src/core/memory.h (+3 -0)

📄 Description

This PR includes proper checks for dmem aliasing (implemented in a naive way for now), and adds three flags to Core::MemoryMapFlags for determining memory type.
For mmap, flag Anon signifies mappings with no backing (flex mem), flag Stack is for mapping stack memory, and flag Void is for reserving memory. These can all be verified through decompiling libkernel, as it uses these flags for mmap calls in the relevant kernel functions.

This PR needs regression testing, primarily in titles with SDK version at or above 2.50. I don't have access to the wider range of games I own, so I can't really test this myself.

Would also be nice to have someone test Red Dead Redemption 2, it is the only game I've seen sceKernelEnableDmemAliasing called in, but I can't test it right now.

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/shadps4-emu/shadPS4/pull/3859 **Author:** [@StevenMiller123](https://github.com/StevenMiller123) **Created:** 12/7/2025 **Status:** ✅ Merged **Merged:** 12/8/2025 **Merged by:** [@georgemoralis](https://github.com/georgemoralis) **Base:** `main` ← **Head:** `quick-mem-fixes` --- ### 📝 Commits (5) - [`0acd69d`](https://github.com/shadps4-emu/shadPS4/commit/0acd69d82c0eb867c9a56be3a614632ee0451ab8) Basic handling for MAP_VOID, MAP_STACK, and MAP_ANON in mmap. - [`1bbb3a6`](https://github.com/shadps4-emu/shadPS4/commit/1bbb3a6e1c2e21a6acbf62f1a4f7b5525ab24c1a) Update memory.cpp - [`110461f`](https://github.com/shadps4-emu/shadPS4/commit/110461f0e5e5561f4c1e680817f0cc33e167825b) Update memory.cpp - [`9cdd547`](https://github.com/shadps4-emu/shadPS4/commit/9cdd547904f3d02e941965796a7201293feaf22b) Dmem aliasing check - [`ea426a8`](https://github.com/shadps4-emu/shadPS4/commit/ea426a8d39fe69a6b4ba2d99b2d88eb7f12cc6be) Oops ### 📊 Changes **2 files changed** (+43 additions, -5 deletions) <details> <summary>View changed files</summary> 📝 `src/core/libraries/kernel/memory.cpp` (+40 -5) 📝 `src/core/memory.h` (+3 -0) </details> ### 📄 Description This PR includes proper checks for dmem aliasing (implemented in a naive way for now), and adds three flags to Core::MemoryMapFlags for determining memory type. For mmap, flag Anon signifies mappings with no backing (flex mem), flag Stack is for mapping stack memory, and flag Void is for reserving memory. These can all be verified through decompiling libkernel, as it uses these flags for mmap calls in the relevant kernel functions. This PR needs regression testing, primarily in titles with SDK version at or above 2.50. I don't have access to the wider range of games I own, so I can't really test this myself. Would also be nice to have someone test Red Dead Redemption 2, it is the only game I've seen sceKernelEnableDmemAliasing called in, but I can't test it right now. --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>