Re: [PATCH v3 4/4] x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

[Xin Li]

On 6/23/2024 1:28 PM, Brian Gerst wrote:
> On Sat, Jun 22, 2024 at 1:14 PM Xin Li (Intel) <xin@xxxxxxxxx> wrote:
> > Generate macros {REQUIRED|DISABLED}_MASK_BIT_SET in the newly added AWK
> > script that generates the required and disabled feature mask header.
> >
> > Suggested-by: Brian Gerst <brgerst@xxxxxxxxx>
> > Signed-off-by: Xin Li (Intel) <xin@xxxxxxxxx>
> > ---
> >   arch/x86/include/asm/cpufeature.h | 69 -------------------------------
> >   arch/x86/tools/featuremasks.awk   | 12 +++++-
> >   2 files changed, 11 insertions(+), 70 deletions(-)

> > -               printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
> > +               printf "\n#define %s_FEATURE(x)\t\t\t\t\\\n", s;
> > +               printf "\t((\t\t\t\t\t";
> > +               for (i = 0; i < ncapints; i++) {
> > +                       if (masks[i])
> > +                               printf "\t\\\n\t\t((x) >> 5) == %2d ? %s_MASK%d :", i, s, i;
> > +               }
> > +               printf " 0\t\\\n";
> > +               printf "\t) & (1 << ((x) & 31)))\n";
>
> The original macro had 1UL here.  I don't know if it is strictly
> necessary in this case since we're using 32-bit masks, but it would
> probably be safer.

I did notice it, but don't think UL is needed.

> > +
> > +               printf "\n#define %s_MASK_BIT_SET(x)\t\t\t\\\n", s;
> > +               printf "\t(%s_FEATURE(x) || BUILD_BUG_ON_ZERO(NCAPINTS != %d))\n\n", s, ncapints;
>
> Checking NCAPINTS isn't necessary anymore.  It was needed when these
> macros had to be manually updated, but now if cpufeatures.h changes
> this header will be regenerated.

Right, it's no longer needed.  Let me update this patch.

Thanks!
    Xin