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Re: Question about copy_from_user()

To: Hiroyuki Machida <machida@sm.sony.co.jp>
Subject: Re: Question about copy_from_user()
From: Ralf Baechle <ralf@oss.sgi.com>
Date: Fri, 18 Feb 2000 12:19:57 +0100
Cc: linux@cthulhu.engr.sgi.com
In-reply-to: <20000216183429L.machida@sm.sony.co.jp>
References: <20000216183429L.machida@sm.sony.co.jp>
Sender: owner-linuxmips@oss.sgi.com
On Wed, Feb 16, 2000 at 06:34:29PM +0900, Hiroyuki Machida wrote:

> I think I found a redundant code in copy_from_user() and
> __copy_from_user() at current CVS asm-mips/uaccess.h.
> 
> I think '*'-marked part in the definiton is obsolete and
> redundant. It had to used in the exception fixup routine as
> commented at arch/mips/lib/memcpy.S. (Of course the comment is also
> obsolete, I think.)

As you say $at is being used for the exception handling, so it obviously
isn't redundant as you say.  Or do I missunderstand what you were trying
to express?

You however made me stump over another bug, the definition of __MODULE_JAL
in <asm/uaccess.h> is wrong when compiling a module.  In that case the
generated code will clobber $at which actually should stay unchanged
for the exception handling.

  Ralf

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