2004-01-13 01:52:09

by Adrian Bunk

[permalink] [raw]
Subject: [2.6 patch] fix DECSTATION depends

Hi Ralf,

it seems the following is required in Linus' tree to get correct depends
for DECSTATION:

--- linux-2.6.1-mm2/arch/mips/Kconfig.old 2004-01-13 02:33:53.000000000 +0100
+++ linux-2.6.1-mm2/arch/mips/Kconfig 2004-01-13 02:36:04.000000000 +0100
@@ -51,7 +51,7 @@

config DECSTATION
bool "Support for DECstations"
- depends on MIPS32 || EXPERIMENTAL
+ depends on MIPS32 && EXPERIMENTAL
---help---
This enables support for DEC's MIPS based workstations. For details
see the Linux/MIPS FAQ on <http://oss.sgi.com/mips/> and the


cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed


2004-01-13 02:30:34

by Ralf Baechle

[permalink] [raw]
Subject: Re: [2.6 patch] fix DECSTATION depends

On Tue, Jan 13, 2004 at 02:52:02AM +0100, Adrian Bunk wrote:

> it seems the following is required in Linus' tree to get correct depends
> for DECSTATION:

Thanks, applied.

Ralf

2004-01-13 13:07:59

by Maciej W. Rozycki

[permalink] [raw]
Subject: Re: [2.6 patch] fix DECSTATION depends

On Tue, 13 Jan 2004, Ralf Baechle wrote:

> > it seems the following is required in Linus' tree to get correct depends
> > for DECSTATION:
>
> Thanks, applied.

The dependency was intentional: stable for 32-bit, experimental for
64-bit. I'm reverting the change immediately. Please always contact me
before applying non-obvious changes for the DECstation.

If there's anything wrong with the depends, it should be fixed elsewhere.
Details, please.

Maciej

--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: [email protected], PGP key available +

2004-01-13 16:41:58

by Ralf Baechle

[permalink] [raw]
Subject: Re: [2.6 patch] fix DECSTATION depends

On Tue, Jan 13, 2004 at 02:07:54PM +0100, Maciej W. Rozycki wrote:

>
> > > it seems the following is required in Linus' tree to get correct depends
> > > for DECSTATION:
> >
> > Thanks, applied.
>
> The dependency was intentional: stable for 32-bit, experimental for
> 64-bit. I'm reverting the change immediately. Please always contact me
> before applying non-obvious changes for the DECstation.

Well, this one seemed to be obvious but sometimes things are not what
they seem to be ...

Ralf

2004-01-13 17:02:27

by Maciej W. Rozycki

[permalink] [raw]
Subject: Re: [2.6 patch] fix DECSTATION depends

On Tue, 13 Jan 2004, Ralf Baechle wrote:

> > The dependency was intentional: stable for 32-bit, experimental for
> > 64-bit. I'm reverting the change immediately. Please always contact me
> > before applying non-obvious changes for the DECstation.
>
> Well, this one seemed to be obvious but sometimes things are not what
> they seem to be ...

Hmm, a change of semantics wouldn't qualify as obvious for me...

I admit this construct may seem surprising at first sight when compared
to many other uses of EXPERIMENTAL -- the equivalent more verbose syntax
used for 2.4 leaves no doubt about the intent, though.

Maciej

--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: [email protected], PGP key available +

2004-01-13 17:28:08

by Adrian Bunk

[permalink] [raw]
Subject: Re: [2.6 patch] fix DECSTATION depends

On Tue, Jan 13, 2004 at 02:07:54PM +0100, Maciej W. Rozycki wrote:
> On Tue, 13 Jan 2004, Ralf Baechle wrote:
>
> > > it seems the following is required in Linus' tree to get correct depends
> > > for DECSTATION:
> >
> > Thanks, applied.
>
> The dependency was intentional: stable for 32-bit, experimental for
> 64-bit. I'm reverting the change immediately. Please always contact me
> before applying non-obvious changes for the DECstation.
>
> If there's anything wrong with the depends, it should be fixed elsewhere.
> Details, please.

Does -mabi=64 really work on any DECstation?

AFAIK none of the R2000, R3x00 and the R4x00 do support the 64bit ABI.

> Maciej

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

2004-01-14 12:01:29

by Maciej W. Rozycki

[permalink] [raw]
Subject: Re: [2.6 patch] fix DECSTATION depends

On Tue, 13 Jan 2004, Adrian Bunk wrote:

> Does -mabi=64 really work on any DECstation?
>
> AFAIK none of the R2000, R3x00 and the R4x00 do support the 64bit ABI.

Well, the R4000 and the R4400 implement the MIPS3 ISA (the R4000 was
actually first to implement it) and are thus obviously 64-bit processors.
And I'm actually using a 64-bit kernel on my R4k DECstations routinely --
currently I'm torturing it on my 5000/260 with gcc 3.4 bootstraps and it
seems quite happy -- it appears rock-solid.

The problem is the official kernel would work fine for a 64-bit
DECstation if it had an R4400 rev.2.0 or later. I haven't heard of any
having such a processor -- the ones I have and the others reported by
poeple have either an R4000 rev.3.0 or an R4400 rev.1.0. These processors
have errata that lead to erroneous behavior in a few common 64-bit
operations (according to the errata sheet, the R4000 actually has a
serious 32-bit erratum as well, but I haven't been able to trigger it
yet). I have implemented appropriate workarounds (available upon
request), but they require changes not only to Linux, but to gcc and gas
as well. I'm preparing to merge the changes to the tools -- hence my
current gcc 3.4 effort -- but until then the 64-bit port has to be marked
as experimental (marking R4000 and R4400 processor selections as such for
64-bit operation would be more accurate, but currently we don't have a
separate setting for them).

See also arch/mips/dec/prom/call_o32.S for the only chunk of explicit
support code for 64-bit operation for the DECstation -- everything else
just works as is (modulo possible protability bugs in drivers).

Going back to the subject -- what's the problem with dependencies?

Maciej

--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: [email protected], PGP key available +