linux-mips
[Top] [All Lists]

Re: Kernel 2.6 for R4600 Indy

To: Ralf Baechle <ralf@linux-mips.org>
Subject: Re: Kernel 2.6 for R4600 Indy
From: "Maciej W. Rozycki" <macro@linux-mips.org>
Date: Tue, 5 Oct 2004 20:35:52 +0100 (BST)
Cc: Thiemo Seufer <ica2_ts@csv.ica.uni-stuttgart.de>, linux-mips@linux-mips.org
In-reply-to: <20041005190408.GD2160@linux-mips.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <4152D58B.608@longlandclan.hopto.org> <20040923154855.GA2550@paradigm.rfc822.org> <20041002185057.GN21351@rembrandt.csv.ica.uni-stuttgart.de> <20041002204014.GO21351@rembrandt.csv.ica.uni-stuttgart.de> <Pine.LNX.4.58L.0410022213140.18388@blysk.ds.pg.gda.pl> <20041004145244.GB8198@linux-mips.org> <Pine.LNX.4.58L.0410050044510.14763@blysk.ds.pg.gda.pl> <20041005190408.GD2160@linux-mips.org>
Sender: linux-mips-bounce@linux-mips.org
On Tue, 5 Oct 2004, Ralf Baechle wrote:

> > 1. The handler is expected to be for R4000/R4400 only.  If it's used for
> 
> You're alone in that believe.  Despite it's name it's being used for
> anything that doesn't need it's own special handler.

 Well, the nearby comment agrees with me.  Is the handler misused or has
someone forgotten to fix the comment (yes, I do know of the R4700 and 
R4640/R4650, with the former being almost identical to the R4600 and the 
latters being unsupported due to lacking a TLB MMU)?

> > 2. The except_vec0_sb1 handler is one with the nop omitted, so it can be
> >    used for these processors.
> 
> Adding more obscurity?

 Just moving it elsewhere. ;-)

> > 3. Correct operation first, only then optimization.
> 
> On of the free software lessons is a bad solution is worse than no solution.

 And another one is anyone is free to provide a better fix.  I suppose 
another alternative with the current implementation is to make a "generic" 
handler separate from the R4000/R4400 one.  This might even be not so 
troublesome maintenance-wise if done properly, but given the "grand plan" 
is it worth the hassle?  Or is the "plan" scheduled for around 2.8 or so?

  Maciej

<Prev in Thread] Current Thread [Next in Thread>