On Fri, Jun 16, 2017 at 11:09:01PM +1000, Jonathan Gray wrote:
> On Fri, Jun 16, 2017 at 02:23:36PM +0200, Mike Belopuhov wrote:
> > On Fri, Jun 16, 2017 at 16:31 +1000, Jonathan Matthew wrote:
> > > Index: arch/i386/include/cpufunc.h
> > > ===================================================================
> > > RCS file: /cvs/src/sys/arch/i386/include/cpufunc.h,v
> > > retrieving revision 1.25
> > > diff -u -p -u -p -r1.25 cpufunc.h
> > > --- arch/i386/include/cpufunc.h 27 May 2017 12:21:50 -0000 1.25
> > > +++ arch/i386/include/cpufunc.h 16 Jun 2017 06:07:16 -0000
> > > @@ -217,6 +217,15 @@ mfence(void)
> > > __asm volatile("mfence" : : : "memory");
> > > }
> > >
> > > +static __inline u_int64_t
> > > +rdtsc(void)
> > > +{
> > > + uint32_t hi, lo;
> > > +
> > > + __asm volatile("rdtsc" : "=d" (hi), "=a" (lo));
> > > + return (((uint64_t)hi << 32) | (uint64_t) lo);
> > > +}
> > > +
> > > static __inline void
> > > wrmsr(u_int msr, u_int64_t newval)
> > > {
> >
> > I think it's OK to get this chunk in. amd64 has got this already.
> >
>
> Perhaps make it __asm volatile ("rdtsc" : "=A" (v)); like the pctr.h version?
>
> That's also what the gcc example uses for rdtsc in
> https://gcc.gnu.org/onlinedocs/gcc/Machine-Constraints.html#Machine-Constraints
>
> I guess the chance of something pretending to be a 486 without TSC attaching
> pvbus is slim.
>
I was going to mention the same thing but I think the risk is low, so ok
mlarkin@ on this if it isn't in already.
-ml
