PACBTI

[thejpster]

Arm Cortex-M85 has optional PACBTI - pointer authentication and branch target identification.

The feature is pacbti and I suspect target-cpu=cortex-m85 turns it on.

[thejpster]

I can't see how to make rustc emit code that uses PACBTI, even with the feature turned on, and writing a function that does sketchy things was pointers to stack buffers.

[thejpster]

https://doc.rust-lang.org/unstable-book/compiler-flags/branch-protection.html says do:

-Z branch-protection=bti,pac-ret,leaf

but this only works on aarch64.