Re: [patch 00/22] x86/treewide: Consolidate CPU match macro maze and get rid of C89 (sic!) initializers

[Andy Shevchenko]

On Fri, Mar 20, 2020 at 3:19 PM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> The x86 CPU matching based on struct x86_cpu_id:
>
>   - is using an inconsistent macro mess with pointlessly duplicated and
>     slightly different local macros. Finding the places is an art as there
>     is no consistent name space at all.
>
>   - is still mostly based on C89 struct initializers which rely on the
>     ordering of the struct members. That's proliferated forever as every
>     new driver just copies the mess from some exising one.
>
> A recent offlist conversation about adding more match criteria to the CPU
> matching logic instead of creating yet another set of horrors, reminded me
> of a pile of scripts and patches which I hacked on a few years ago when I
> tried to add something to struct x86_cpu_id.
>
> That stuff was finally not needed and ended up in my ever growing todo list
> and collected dust and cobwebs, but (un)surprisingly enough most of it
> still worked out of the box. The copy & paste machinery still works as it
> did years ago.
>
> There are a few places which needed extra care due to new creative macros,
> new check combinations etc. and surprisingly ONE open coded proper C99
> initializer.
>
> It was reasonably simple to make it at least compile and pass a quick
> binary equivalence check.
>
> The result is a X86_MATCH prefix based set of macros which are reflecting
> the needs of the usage sites and shorten the base macro which takes all
> possible parameters (vendor, family, model, feature, data) and uses proper
> C99 initializers.
>
> So extensions of the match logic are trivial after that.
>

Thank you, Thomas!

Briefly looking to the code, I like the idea. I'll do (minor) comments
on individual patches.

I see it incorporates my previous attempts to extend this, but now it
looks better.

> The patch set is against Linus tree and has trivial conflicts against
> linux-next.
>
> The diffstat is:
>  71 files changed, 525 insertions(+), 472 deletions(-)
>
> but the extra lines are pretty much kernel-doc documentation which I added
> to each of the new macros. The usage sites diffstat is:
>
>  70 files changed, 393 insertions(+), 471 deletions(-)
>
> Thoughts?
>
> Thanks,
>
>         tglx
>
>


-- 
With Best Regards,
Andy Shevchenko