Re: [PATCH 00/36] AArch64 Linux kernel port

[Catalin Marinas]

On Wed, Jul 18, 2012 at 04:27:12PM +0100, Dennis Gilmore wrote:
> El Tue, 17 Jul 2012 22:33:33 -0400
> Jon Masters <jonathan@xxxxxxxxxxxxxx> escribió:
> > On 07/17/2012 06:35 PM, Joe Perches wrote:
> > > On Tue, 2012-07-17 at 23:18 +0100, Catalin Marinas wrote:
> > > 
> > >> The uname will still report
> > >> "aarch64" to match the compiler triplet and also avoid confusion of
> > >> existing 32-bit ARM scripts that simply check for "arm*" in the
> > >> machine name.
> 
> that means that the yum base arch will need to be aarch64 and the arch
> used in rpm will be aarch64 also. its throwing something weird and
> confusing right in the face of users. I urge you to change it all to
> arm64 just changing the directory in the kernel is pointless as it still
> exposes all the weirdness of the name to users and will result in a
> large amount of education and a constant stream of the same question
> "Where do i find the arm64 bits?" until such time as the users learn
> that arm64 is aarch64. All the tooling uses "uname -m" to determine the
> package architecture.

The directory name change is just to avoid some word duplication in
arch/aarch64/. It can be a64 (as per the ISA) or aa64 or whatever else.
The "arm64" got most votes so far. I still prefer "aarch64" for
consistency but I'm can change the directory name, it doesn't matter
much.

As for the "aarch64" name, whether we like it were not, it was chosen by
ARM Ltd to describe the new execution mode. It is one of the few
constants in the changing world of architecture versions and CPU
numbers. It's also a clear separation from the multitude of ARM* names
which I agree, is confusing (and, BTW, we had ARM6 processors as well).

People that have been involved with this architecture don't find the
name impossible (and not all of them are based in Cambridge ;). It may
not be as aesthetic and easy to pronounce as "arm64" but you get used to
it. I personally find it easier to pronounce (and type) than "x86_64".

Just to be clear, I'm not trying to defend the "beauty" of this name (I
have my own opinion) but we spend too much time arguing about it. This
name has implications beyond the technical arguments of some script or
another and it will be found in all the technical documents produced by
ARM Ltd (including the next ARM Architecture Reference Manual).

> The triplet that fedora will use will be preferred
> arm64-redhat-linux-gnu or aarch64-redhat-linux-gnu

Gcc already went for aarch64-*. I really doubt they are willing to
change it but you can try.

> but again aarch64 will propogate to a lot of highly visible places
> where it will just cause undue confusion.

Debian has different names for the architecture and compiler triplet:
amd64 with x86_64-linux-gnu, similar for x32. None of these match the
arch/x86/ Linux directory. Even if there is some confusion initially, it
will go away in a relatively short time (if not ARM can sponsor a water
drinking event ;).

-- 
Catalin
(really thirsty ;)
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