Re: [PATCH V8 04/44] x86/pkeys: Add additional PKEY helper macros

[Ira Weiny]

On Wed, Feb 02, 2022 at 12:26:44PM -0800, Dave Hansen wrote:
> On 2/2/22 12:21, Ira Weiny wrote:
> > On Fri, Jan 28, 2022 at 02:47:30PM -0800, Dave Hansen wrote:
> >> #define PKR_WD_MASK(pkey)	(PKR_WD_BIT << PKR_PKEY_SHIFT(pkey))
> >>
> >> Which says, "generate a write-disabled mask for this pkey".
> > 
> > I think the confusion comes from me having used these as mask values rather
> > than what PKR_AD_KEY() was intended to be used for.
> > 
> > In the previous patch PKR_AD_KEY() is used to set up the default user pkey
> > value...
> > 
> > u32 init_pkru_value = PKR_AD_KEY( 1) | PKR_AD_KEY( 2) | PKR_AD_KEY( 3) |
> > 		      PKR_AD_KEY( 4) | PKR_AD_KEY( 5) | PKR_AD_KEY( 6) |
> > 		      PKR_AD_KEY( 7) | PKR_AD_KEY( 8) | PKR_AD_KEY( 9) |
> > 		      PKR_AD_KEY(10) | PKR_AD_KEY(11) | PKR_AD_KEY(12) |
> > 		      PKR_AD_KEY(13) | PKR_AD_KEY(14) | PKR_AD_KEY(15);
> > 
> 
> Hah, I'm complaining about my own code.
> 
> > u32 init_pkru_value = PKR_AD_MASK( 1) | PKR_AD_MASK( 2) | PKR_AD_MASK( 3) |
> > 		      PKR_AD_MASK( 4) | PKR_AD_MASK( 5) | PKR_AD_MASK( 6) |
> > 		      PKR_AD_MASK( 7) | PKR_AD_MASK( 8) | PKR_AD_MASK( 9) |
> > 		      PKR_AD_MASK(10) | PKR_AD_MASK(11) | PKR_AD_MASK(12) |
> > 		      PKR_AD_MASK(13) | PKR_AD_MASK(14) | PKR_AD_MASK(15);
> > 
> > It seems odd to me.  Does it seem odd to you?
> 
> Looks OK to me.  It's build a "value" out of a bunch of individual masks.
> 
> > Looking at the final code I think I'm going to just drop the usages in this
> > patch and add PKR_WD_KEY() where it is used first.
> > 
> > Also, how about PKR_KEY_INIT_{AD|WD|RW}() as a name?
> 
> For the PKR_AD_KEY() macro?

Yes if I drop this patch then the only place these are used is to initialize
the registers.

Ira