On Sat, Jan 6, 2018 at 10:39 AM, Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote: [..] >> retpoline is variant-2, this patch series is about variant-1. > > that's exactly the point. Don't slow down the kernel with lfences > to solve variant 1. retpoline for 2 is ok from long term kernel > viability perspective. > Setting aside that we still need to measure the impact of these changes the end result will still be nospec_array_ptr() sprinkled in various locations. So can we save the debate about what's inside that macro on various architectures and at least proceed with annotating the problematic locations? Perhaps we can go a step further and have a config option to switch between the clever array_access() approach from Linus that might be fine depending on the compiler, and the cpu-vendor-recommended not to speculate implementation of nospec_array_ptr().
