On 11/09/2017 06:25 PM, Andy Lutomirski wrote: > Here are two proposals to address this without breaking vsyscalls. > > 1. Set NX on low mappings that are _PAGE_USER. Don't set NX on high > mappings but, optionally, warn if you see _PAGE_USER on any address > that isn't the vsyscall page. > > 2. Ignore _PAGE_USER entirely and just mark the EFI mm as special so > KAISER doesn't muck with it.
These are totally doable. But, what's the big deal with breaking native vsyscall? We can still do the emulation so nothing breaks: it is just slow.
