On Wed, Jan 10, 2018 at 10:35:58PM -0500, Brian Gerst wrote: > > @@ -263,6 +271,7 @@ entry_SYSCALL_64_fastpath: > > #endif > > ja 1f /* return -ENOSYS (already > > in pt_regs->ax) */ > > movq %r10, %rcx > > + xor %r10, %r10 > > RCX is already clear, so xchgq %r10, %rcx will be simpler.
XOR is special cased by the hardware, so it's always more efficient. -Andi >
