On Mon, Oct 09, 2023 at 06:31:13PM +0200, Miguel Ojeda wrote: > On Mon, Oct 9, 2023 at 6:01 PM Matthew Maurer <mmaurer@xxxxxxxxxx> wrote: > > > > If the IBT part would be helpful by itself immediately, I can split > > that out - it's only the KCFI portion that won't currently work. > > Thanks Matthew. I don't think we are in a rush, but if it is not too > much work to split it, that would be great, instead of adding the > restriction. > > For retthunk, by the way, I forgot to mention to Greg above that (in > the original discussion with PeterZ) that I did a quick test back then > to hack the equivalent of `-mfunction-return=thunk-extern` into > `rustc` to show that the compiler could use it via LLVM (by passing > the attribute in the IR). At least at a basic level it seemed to work: > I got a userspace program to count the times that it went through the > return thunk. I didn't try to do anything on the kernel side, but at > least for the compiler side, it seemed OK. So it may be way easier (on > the compiler side) than the CFI work? It should hopefully be much easier than CFI, it was a much simpler change to gcc and clang when it landed. thanks, greg k-h
