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From: Segher Boessenkool <segher@kernel•crashing.org>
To: Arnd Bergmann <arnd@arndb•de>
Cc: linuxppc-dev@ozlabs•org
Subject: Re: 440 ebony patch seems to have broken 85xx build on powerpc.git
Date: Fri, 25 May 2007 00:02:44 +0200	[thread overview]
Message-ID: <ab81cfaedb70d6911fcbac9c43f5cf69@kernel.crashing.org> (raw)
In-Reply-To: <200705242221.17790.arnd@arndb.de>

>>> Nothing is telling GCC what CPU to compile for, so it
>>> will just use the compiler's default, which very likely
>>> is not what you want. =A0For files that will only ever
>>> be used on 440, the correct flags are -mcpu=3D440 -Wa,-m440 .
>>
>> We could add that to the per-file flags already, right?
>
> I think it should really use -mcpu=3Dpowerpc on all files.
> The problem that Dave saw was the result of using a compiler
> that defaults to -mcpu=3D8540, which uses instruction that
> don't work on 440.

No, those options _do_ work on 440, but the -mbooke
assembler flag disallows isel (since it is an optional
insn).

> The common files really need to be built with -mcpu flags that
> make the code work on any system if you want to be able
> to use just a single boot wrapper binary for all.

On any system where they can run at all, yes.  It should
be fine to compile a 440-only file with 440-specific flags.


Segher

  parent reply	other threads:[~2007-05-24 22:02 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-24 17:13 440 ebony patch seems to have broken 85xx build on powerpc.git Dave Jiang
2007-05-24 17:37 ` Josh Boyer
2007-05-24 17:43   ` Dave Jiang
2007-05-24 18:02 ` Sergei Shtylyov
2007-05-24 18:09   ` Josh Boyer
2007-05-25  1:27     ` David Gibson
2007-05-24 19:05 ` Segher Boessenkool
2007-05-24 19:39   ` Josh Boyer
2007-05-24 20:18     ` Segher Boessenkool
2007-05-24 20:21     ` Arnd Bergmann
2007-05-24 20:24       ` Josh Boyer
2007-05-24 21:07         ` Mark A. Greer
2007-05-24 21:16         ` Arnd Bergmann
2007-05-24 22:08           ` Segher Boessenkool
2007-05-24 22:03         ` Segher Boessenkool
2007-05-24 22:02       ` Segher Boessenkool [this message]
2007-05-25  1:30         ` David Gibson
2007-05-25 14:01           ` Segher Boessenkool
2007-05-24 22:09   ` Segher Boessenkool

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