Mixing code and data, right? I think the downside here is if you tried to install another hook it’d fail because the LDE wouldn’t be able to make heads or tails of the address. I suggest embedding the value into something with an imm64 argument (mov?) so that LDEs can handle it.

I guess also though, at ~16 bytes its probably deep enough into the function that it may no longer be position independent, or hell, maybe the function isn’t even that long to begin with.

If you're writing a hooking library / a hook you should be keeping track of where they are. It's a big hook, that is true but it's also one that doesn't spoil a register and is pretty straightforward to add. It's a tradeoff.

Well the bigger problem imo is other hook engines that might also be roaming around the process space. I think all you need is two extra bytes to make it valid instructions, and in theory then nested hooking should work fine. Though it only exacerbates the length issue.

if you place the data at the end of the trampoline it avoids these issues of mixing data and code, it's like a little custom data segment you make since you have to allocate the trampoline anyways. This is what i do in my lib. The disp is after the jmp the trampoline uses to jmp back to the original. The original function only has the jmp [disp] and no data is mixed.