Deny instrumentation of arm64 native code by x86 and x64 detours.

[Andrey Shedel (ashedel)]

This change adds the logic to deny writing over the native arm64 code when running x64/x86 detours in EC emulation mode.

[Copilot]

Pull request overview

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Adds a guard in DetourAttachEx to prevent x86/x64 detours from patching ARM64EC/native targets on ARM64 Windows (EC emulation scenario), avoiding illegal-instruction crashes.

Changes:

• Introduces ARM64EC/ARM64 detection helpers for x86/x64 builds.
• Blocks DetourAttachEx when the target pointer is determined to be ARM64EC/ARM64 and returns an error.
• Minor formatting cleanup in ARM64 indirect jump generation code.

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[Andrea Allievi (AaLl86)]

Reviewed

[Andrea Allievi (AaLl86)]

Why you do not set this at the end of the block? Because two initializations can happen in parallel? If so, is it not better to use serialized read instructions?

[Andrea Allievi (AaLl86)]

They do not use (hKernel32 != NULL) in this repro? :-)

[mirh]

Excuse me, this PR makes a lot of sense and all.
But if you are giving up touching emulated code altogether.. how exactly is detours supposed to work with system libraries?

[Charles Milette (sylveon)]

Would make more sense to me to enlighten Detours to write the proper ARM64 code for a redirect, but I don't know what that involves exactly.

[Ratin Gao (RatinCN)]

mirhCharles Milette (@sylveon) and others interested in ARM64EC compatibility, I have implemented ARM64EC compatibility in KNSoft#30. When the hook DLL is built for ARM64EC, it can correctly hook both x64 and ARM64EC target functions in x64 and ARM64EC processes on ARM64 systems. Only some documentation updates remain. I will finish it asap.

[Ratin Gao (RatinCN)]

mirhCharles Milette (@sylveon) and others interested in ARM64EC compatibility, I have implemented ARM64EC compatibility in KNSoft#30. When the hook DLL is built for ARM64EC, it can correctly hook both x64 and ARM64EC target functions in x64 and ARM64EC processes on ARM64 systems. Only some documentation updates remain. I will finish it asap.

Done, I've fixed this in my KNSoft.SlimDetours.
PR: Support hooking ARM64EC target functions,
Release v1.2.2-beta
TechWiki: Implement ARM64EC Compatibility
I'll also port the fix to Microsoft Detours as soon as possible. However, I’m not sure when the maintainers will respond, as many of my previous PRs have received no response.

[mirh]

Thank you so much for even detailing that thing I wanted to ask you, about why a x64 dll could not force emit an arm64 jmp.

I'm looking forward to your port, which is going to be precious for a lot of game mods.

[Ratin Gao (RatinCN)]

Thank you so much for even detailing that thing I wanted to ask you, about why a x64 dll could not force emit an arm64 jmp.

I'm looking forward to your port, which is going to be precious for a lot of game mods.

Done. #388

[Andrey Shedel (ashedel)]

Thank you so much for even detailing that thing I wanted to ask you, about why a x64 dll could not force emit an arm64 jmp.
I'm looking forward to your port, which is going to be precious for a lot of game mods.

Done. #388

Thank you! Will look into it asap.