Re: [PATCH] Revert "MIPS: mm: tlbex: Use cpu_has_mips_r2_exec_hazard for the EHB instruction"

From: "Maciej W. Rozycki" <macro@linux-mips.org>
To: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org, ralf@linux-mips.org,
	linux-kernel@vger.kernel.org,
	Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>,
	Markos Chandras <markos.chandras@imgtec.com>,
	David Daney <david.daney@cavium.com>
Subject: Re: [PATCH] Revert "MIPS: mm: tlbex: Use cpu_has_mips_r2_exec_hazard for the EHB instruction"
Date: Tue, 24 Feb 2015 01:10:58 +0000 (GMT)	[thread overview]
Message-ID: <alpine.LFD.2.11.1502240059330.17311@eddie.linux-mips.org> (raw)
In-Reply-To: <1424731974-27926-1-git-send-email-ddaney.cavm@gmail.com>

On Mon, 23 Feb 2015, David Daney wrote:

> From: David Daney <david.daney@cavium.com>
> 
> This reverts commit 77f3ee59ee7cfe19e0ee48d9a990c7967fbfcbed.
> 
> There are two problems:
> 
> 1) It breaks OCTEON, which will now crash in early boot with:
> 
>   Kernel panic - not syncing: No TLB refill handler yet (CPU type: 80)
> 
> 2) The logic is broken.
> 
> The meaning of cpu_has_mips_r2_exec_hazard is that the EHB instruction
> is required.  The offending patch attempts (and fails) to change the
> meaning to be that EHB is part of the ISA.
> 
> Signed-off-by: David Daney <david.daney@cavium.com>
> ---

 Code affected will have to be reconsidered including possibly older 
changes as well.  Meanwhile, to revert the immediate regression, you have 
my:

Reviewed-by: Maciej W. Rozycki <macro@linux-mips.org>

Next time please try to use the imperative mood for the commit message 
though, as per Documentation/SubmittingPatches.

 Overall I think it makes sense to have a look back there every once in a 
while to avoid getting trapped in routine.  Some breakage we fall into 
from time to time results from missing the guidelines set there, sigh.

  Maciej