In-Reply-To: <200906140023.06690.arnd@arndb.de>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-arch@vger.kernel.org,
       linux-kernel@vger.kernel.org, torvalds@linux-foundation.org
MIME-Version: 1.0
Subject: Re: [PATCH 07/27] score: create head files elf.h emergency-restart.h
 errno.h
Message-ID: <OF48364F7F.ED6F93C7-ON482575D6.0042A7E0-482575D6.0043654D@sunplusct.com>
From: liqin.chen@sunplusct.com
Date: Mon, 15 Jun 2009 20:11:34 +0800
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Arnd Bergmann <arnd@arndb.de> д?? 2009-06-14 06:23:06:

> On Saturday 13 June 2009, liqin.chen@sunplusct.com wrote:
> > > 
> > > EMAXERRNO is mips specific right now. Do you actually need it 
somewhere?
> > > 
> > 
> > Yes, I used it in entry.S, maybe I could remove this define latter.
> > 
> 
> Ok. Note that the maximum error number that is supposed to get sent back
> to user space is 511. Most architectures check the return value of the
> system call to be between -4095 and zero upon entering user space.
> Checking it in the kernel gives you the chance to override the
> error status from a system call with force_successful_syscall_return().
> 
> If that is your intention, you should probably leave the definition in 
there.
> Powerpc uses _LAST_ERRNO for the same purpose, which is somewhat 
inconsistent
> with mips and also uses a different value to compare against.
> 

Maybe I can don't use EMAXERRNO in score code. But I think define a 
maximum error number in asm-generic/errno.h is better.

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