Re: [RFC 1/5] x86: Clean up cr4 manipulation

[Borislav Petkov]

On Thu, Oct 16, 2014 at 10:16:33AM +0200, Peter Zijlstra wrote:
> On Tue, Oct 14, 2014 at 03:57:35PM -0700, Andy Lutomirski wrote:
> > +/* Set in this cpu's CR4. */
> > +static inline void cr4_set(unsigned long mask)
> > +{
> > +	unsigned long cr4;
> > +
> > +	cr4 = read_cr4();
> > +	cr4 |= mask;
> > +	write_cr4(cr4);
> > +}
> > +
> > +/* Clear in this cpu's CR4. */
> > +static inline void cr4_clear(unsigned long mask)
> > +{
> > +	unsigned long cr4;
> > +
> > +	cr4 = read_cr4();
> > +	cr4 &= ~mask;
> > +	write_cr4(cr4);
> > +}
> 
> I would have called these cr4_or() and cr4_nand(). When first reading
> this I expected cr4_set() to be a pure write_cr4() and cr4_clear() to do
> write_cr4(0) -- which obviously doesn't make too much sense.
> 
> 
> cr4_{set,clear}_mask() might maybe be clearer but is more typing, and
> the logical ops as suggested should have unambiguous meaning.

Or maybe ...{set,clear}_bits() because we're setting/clearing a mask of
a bunch of bits...

-- 
Regards/Gruss,
    Boris.
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