On Wed, May 11, 2016 at 12:11 AM, Borislav Petkov <b...@suse.de> wrote: > On Tue, May 10, 2016 at 03:30:48PM -0700, H. Peter Anvin wrote: >> I didn't mean inline assembly. > > How does that matter? > > The problem is having as less insn bytes as possible and the minimal > size we can do is issuing POPCNT everywhere which is 4 or 5 bytes. The > alternatives then replace that with a CALL which is also 5 bytes. > > The way I did it now, it adds 22K more to allyesconfig vmlinux due to > the static_cpu_has doubled alternatives sections and the JMPs. The > thunks will keep those 5 bytes *and* get rid of the calling convention > without the growth. > > Or?
I think he meant the out of line version would be asm, so you could control what registers were clobbered. -- Brian Gerst
