Re: [PATCH 1/6] x86/entry: Introduce local_db_{save,restore}()

[Peter Zijlstra]

On Fri, May 29, 2020 at 10:28:33AM -0700, Andy Lutomirski wrote:
> > +static __always_inline unsigned long local_db_save(void)
> > +{
> > +    unsigned long dr7;
> > +
> > +    get_debugreg(&dr7, 7);
> > +    dr7 ^= 0x400;
> 
> Why xor?  This seems extra confusing.

I'll do the normal mask thing ..