[U-Boot] [PATCH v2] arm: Switch to -mno-unaligned-access when supported by the compiler

Albert ARIBAUD
2014-02-10T16:12:24Z

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.