Subject: [PATCH] ARM: /proc/cpuinfo: Use DT machine name when possible

From: [email-masked] (Pali Rohár)
Date: Fri, 5 Sep 2014 15:52:05 +0200

On Friday 05 September 2014 15:45:42 Mark Rutland wrote:
> On Fri, Sep 05, 2014 at 12:38:40PM +0100, Pali Roh?r wrote:
> > On Wednesday 18 June 2014 18:54:24 Pali Roh?r wrote:
> > > Machine name from board description is some generic name
> > > on DT kernel. DT provides machine name property which is
> > > specific for board, so use it instead generic one when
> > > possible.
> > > 
> > > Signed-off-by: Pali Roh?r <[email-masked]>
> > > ---
> > > 
> > >  arch/arm/kernel/setup.c |    7 +++++--
> > >  1 file changed, 5 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/arch/arm/kernel/setup.c
> > > b/arch/arm/kernel/setup.c index 8a16ee5..fbc7b4f 100644
> > > --- a/arch/arm/kernel/setup.c
> > > +++ b/arch/arm/kernel/setup.c
> > > @@ -875,10 +875,13 @@ void __init setup_arch(char
> > > **cmdline_p)
> > > 
> > >  	setup_processor();
> > >  	mdesc = setup_machine_fdt(__atags_pointer);
> > > 
> > > -	if (!mdesc)
> > > +	if (mdesc)
> > > +		machine_name = of_flat_dt_get_machine_name();
> > > +	else
> > > 
> > >  		mdesc = setup_machine_tags(__atags_pointer,
> > > 
> > > __machine_arch_type); machine_desc = mdesc;
> > > -	machine_name = mdesc->name;
> > > +	if (!machine_name)
> > > +		machine_name = mdesc->name;
> > > 
> > >  	if (mdesc->reboot_mode != REBOOT_HARD)
> > >  	
> > >  		reboot_mode = mdesc->reboot_mode;
> > 
> > So, do you really want to break userspace which reading file
> > /proc/cpuinfo (after migration from boardcode --> DT)?
> 
> You have no guarantee model name in the DT == the name in a
> board file anyhow, and trying to force that is wrong. So
> further to Russell's reply, I must NAK this from a DT
> perspective.
> 
> Realistically your userspace is already broken if relying on
> such things. You built something that only ever worked for a
> particular arbitrary string. So it was already broken for
> every other board, and there was never any guarantee that new
> boards where your userspace could have worked would share the
> same name.
> 
> You're trying to fix the wrong side of the equation.
> 
> Mark.

So what is your suggestion for identifing board (name/type) which 
will work with any kernel (and will not be broken again by kernel 
later)?

-- 
Pali Roh?r
pali.rohar at gmail.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part.
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20140905/6e3c7aea/attachment.sig>