Re: [PATCH v10 04/10] arm64/sysreg: Add a comment that the sysreg file should be sorted

[James Clark]

On 14/01/2025 6:16 pm, Rob Herring wrote:
> On Mon, Jan 13, 2025 at 10:49 AM Marc Zyngier <maz@xxxxxxxxxx> wrote:
> > On Mon, 13 Jan 2025 15:43:39 +0000,
> > James Clark <james.clark@xxxxxxxxxx> wrote:
> > > On 12/01/2025 12:49 pm, Marc Zyngier wrote:
> > > > On Tue, 07 Jan 2025 11:32:41 +0000,
> > > > James Clark <james.clark@xxxxxxxxxx> wrote:
> > > > > From: James Clark <james.clark@xxxxxxx>
> > > > >
> > > > > There are a few entries particularly at the end of the file that aren't
> > > > > in order. To avoid confusion, add a comment that might help new entries
> > > > > to be added in the right place.
> > > > >
> > > > > Reviewed-by: Mark Brown <broonie@xxxxxxxxxx>
> > > > > Signed-off-by: James Clark <james.clark@xxxxxxx>
> > > > > Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
> > > > > ---
> > > > >    arch/arm64/tools/sysreg | 2 ++
> > > > >    1 file changed, 2 insertions(+)
> > > > >
> > > > > diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
> > > > > index b081b54d6d22..4ba167089e2a 100644
> > > > > --- a/arch/arm64/tools/sysreg
> > > > > +++ b/arch/arm64/tools/sysreg
> > > > > @@ -48,6 +48,8 @@
> > > > >    # feature that introduces them (eg, FEAT_LS64_ACCDATA introduces enumeration
> > > > >    # item ACCDATA) though it may be more taseful to do something else.
> > > > >    +# Please try to keep entries in this file sorted by sysreg
> > > > > encoding.
> > > > > +
> > > > >    Sysreg   OSDTRRX_EL1     2       0       0       0       2
> > > > >    Res0     63:32
> > > > >    Field    31:0    DTRRX
> > > >
> > > > "Do as I say, don't do as I do".
> > > >
> > > > I don't think this makes any sense if we don't actually sort the file
> > > > the first place.
> > > >
> > > >      M.
> > >
> > > I think it's ok if it avoids review comments that new entries should
> > > be sorted. Or maybe we do the opposite and the comment should say this
> > > file is allowed to be unsorted...
> >
> > The better option would be to add the comment *and* sort the file.
> > Leading by example has some value, it seems.
>
> IME, it's better if documentation just states what the tools enforce.
>
> Can't we add something like this to the header generation:
>
> $ grep '^Sysreg\s' arch/arm64/tools/sysreg | sort -n -k3 -k4 -k5 -k6 -k7 -c
> sort: -:22: disorder: Sysreg ID_MMFR4_EL1       3       0       0
>   2       6
>
> Rob

Actually I updated gen-sysreg.awk to fail the build if it's not sorted, 
was just about to post it. I don't know if a build failure or a warning 
is preferred but I can do either.

James