On Sat, May 23, 2020 at 02:13:46PM -0700, Jason Thorpe wrote: > > > On May 23, 2020, at 11:08 AM, Ryo Shimizu <r...@netbsd.org> wrote: > > > > Module Name: src > > Committed By: ryo > > Date: Sat May 23 18:08:59 UTC 2020 > > > > Modified Files: > > src/sys/arch/aarch64/aarch64: cpufunc.c cpuswitch.S exec_machdep.c > > genassym.cf netbsd32_machdep.c vectors.S vm_machdep.c > > src/sys/arch/aarch64/include: armreg.h machdep.h proc.h > > > > Log Message: > > Not only the kernel thread, but also the userland PAC keys > > (APIA,APIB,APDA,APDB,APGA) are now randomly initialized at exec, and > > switched > > when context switch. > > userland programs are able to perform pointer authentication on ARMv8.3+PAC > > cpu. > > Has any consideration be given to perhaps creating a new MACHINE_ARCH for > this, or somehow otherwise decorating the ELF files to indicate their > exec-ability?
I am under the impression that PAC was designed to be forewards compatible, so older CPUs can execute code with this annotation. I don't whether it works in practice though.