On Fri, May 15, 2020 at 8:13 AM Will Deacon <w...@kernel.org> wrote: > But it also > means that nobody is using this on arm64, so we could also consider removing > it entirely. Did you spot this because you are trying to use it for > something or just by inspection/unit-testing?
No, I was trying to port a tool from x86 and nothing made sense for many hours :). (it was quite a bit of debugging, because the syscall that it was supposed to skip installed a seccomp filter, which then later veto'd random syscalls making the symptoms quite confusing). Having PTRACE_SYSEMU isn't critical, but we might as well support it. It makes things a bit more efficient and is probably safer (if it works correctly ;). The patch is fairly small. Will validate and then send it here for review. Keno