Subject: Re: [PATCH] enable RTAS /proc for PowerPC/CHRP platform

From: Sven Luther <[email-masked]>
Date: Fri, 20 Oct 2006 08:58:50 +0200

On Fri, Oct 20, 2006 at 08:44:56AM +0200, Olaf Hering wrote:
> On Fri, Oct 20, Sven Luther wrote:
> 
> > Ben, would it make sense to add two informations to /proc/cpuinfo ?
> > It would be great to have a field there which will allow to check for the
> > kernel flavour to run, namely if the kernel/processor/whatever is running in
> > 32bit or 64bit mode. The second field would be a generalized machine field,
> > or plateform or whatever, which would easily allow to differentiate between an
> > apple machine, a ibm chrp, a pegasos or other genesi product, etc. Without
> > necessarily having to maintain a huge amount of userlanf mappings from all
> > those different machine: fields, which all have CHRP, true, but no finer
> > grained informations, while we do have it in the kernel.
> 
> /proc/device-tree/{model,device_type,compatible} is enough to map

Yeah, well.

> everything reliable in the installer. Dont pollute /proc/cpuinfo
> further. There has already enough stuff that doesnt belong there, like
> pmac-generation, 'pmac flags', 'detected as', motherboard and machine.
> Oh, and bogomips...

Exact, it is not about poluting, but about rationalizing. The fact is that
these are the two infos that are the most necessary to userland, then why
disseminate the info in thousand different places, instead of making it easily
available in a canonical place in a standard format for everyone ? 

> About 32bit/64bit, maybe VmallocTotal from /proc/meminfo can be used.
> incredible large numer == must be a 64bit kernel
> No idea how reliable it is. There are those 36bit systems, but I bet
> they dont run a distro.

This sounds like the ugliest hack i have seen around, and is prone to break. A
proper /proc/cpuinfo flag would be most welcome to solve this cleanly.

Friendly,

Sven Luther