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From: Albert ARIBAUD <albert.u.boot@aribaud.net>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH v2] arm: Switch to -mno-unaligned-access when supported by the compiler
Date: Mon, 10 Feb 2014 17:12:24 +0100	[thread overview]
Message-ID: <20140210171224.477e2906@lilith> (raw)
In-Reply-To: <yw1xeh3batjq.fsf@unicorn.mansr.com>

Hi M?ns,

On Mon, 10 Feb 2014 15:14:49 +0000, M?ns Rullg?rd <mans@mansr.com>
wrote:

> Albert ARIBAUD <albert.u.boot@aribaud.net> writes:
> 
> > Hi Tom,
> >
> > On Mon, 10 Feb 2014 08:21:39 -0500, Tom Rini <trini@ti.com> wrote:
> >
> >> On Mon, Feb 10, 2014 at 10:24:47AM +0100, Albert ARIBAUD wrote:
> >> > Hi Tom,
> >> > 
> >> > On Tue,  4 Feb 2014 12:05:33 -0500, Tom Rini <trini@ti.com> wrote:
> >> > 
> >> > > When we tell the compiler to optimize for ARMv7 it assumes a default of
> >> > > unaligned accesses being supported at the hardware level and can make
> >> > > use of this to perform what it deems as an optimization in any case,
> >> > > including allowing for data to become unaligned.  We explicitly disallow
> >> > > this hardware feature so we must tell the compiler.
> >> > > 
> >> > > Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
> >> > > Cc: Mans Rullgard <mans@mansr.com>
> >> > > Signed-off-by: Tom Rini <trini@ti.com>
> >> > 
> >> > NAK -- the discrepancy between the compiler being told to allow native
> >> > unaligned accesses while at the same time telling the hardware to trap
> >> > them is conscious and voluntary. It was chosen to help detect unaligned
> >> > accesses which are rarely necessary and can be explicitly performed by
> >> > software on a case by case basis.
> >> > 
> >> > If and when a specific file requires unaligned access which cannot be
> >> > made by some other mean than enabling -mno-unaligned-access, then this
> >> > file should have it added, not the whole of U-Boot.
> >> 
> >> Right, I recall the discussion, and we chose wrong.
> >
> > I am quite prepared to discuss whether we chose wrong or right, and
> > to change my mind when the conditions are right, but I'll need more than
> > such a short and simple statement. :)
> 
> I already gave you a detailed explanation some months ago.  You refused
> to read it.

I can hardly have "refused to read" a message which I *answered*, laid
out how I thought the issue should be solved... and got no answer after
this.

Now, are we going to discuss the technical issue or is this going to go
debian-TC -- which I wouldn't see the point of.

Amicalement,
-- 
Albert.

  parent reply	other threads:[~2014-02-10 16:12 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-04 17:05 [U-Boot] [PATCH v2] arm: Switch to -mno-unaligned-access when supported by the compiler Tom Rini
2014-02-04 17:35 ` Måns Rullgård
2014-02-10  9:24 ` Albert ARIBAUD
2014-02-10 13:21   ` Tom Rini
2014-02-10 14:57     ` Albert ARIBAUD
2014-02-10 15:14       ` Måns Rullgård
2014-02-10 15:40         ` Måns Rullgård
2014-02-10 16:12         ` Albert ARIBAUD [this message]
2014-02-10 16:21           ` Måns Rullgård
2014-02-10 16:24           ` Tom Rini
2014-02-10 17:26             ` Albert ARIBAUD
2014-02-10 18:54               ` Wolfgang Denk
2014-02-10 21:26               ` Tom Rini
2014-02-10 22:17                 ` Wolfgang Denk
2014-02-10 22:28                   ` Tom Rini
2014-02-11  8:19                     ` Wolfgang Denk
2014-02-11 12:37                       ` Måns Rullgård
2014-02-11 14:43                         ` Wolfgang Denk
2014-02-11 15:33                           ` Måns Rullgård
2014-02-11 16:37                             ` Albert ARIBAUD
2014-02-11 16:44                               ` Måns Rullgård
2014-02-11 17:11                                 ` Albert ARIBAUD
2014-02-11 17:21                                   ` Albert ARIBAUD
2014-02-12 14:35                               ` Tom Rini
2014-02-12 16:19                                 ` Albert ARIBAUD
2014-02-17 15:45                                   ` Tom Rini
2014-02-17 15:55                                     ` Albert ARIBAUD
2014-02-11 18:18                             ` Wolfgang Denk
2014-02-11 18:21                               ` Måns Rullgård
2014-02-11  8:44                     ` Albert ARIBAUD
2014-02-12 14:25                       ` Tom Rini
2014-02-12 15:51                         ` Wolfgang Denk
2014-02-10 15:21       ` Tom Rini

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