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From: WANG Cong <xiyou.wangcong@gmail.com>
To: Jeff Dike <jdike@addtoit.com>
Cc: akpm@osdl.org, WANG Cong <xiyou.wangcong@gmail.com>,
	linux-kernel@vger.kernel.org,
	user-mode-linux-devel@lists.sourceforge.net
Subject: Re: [uml-devel] [PATCH 2/19] UML - Tidy stub management code
Date: Tue, 29 Apr 2008 15:57:24 +0800 (CST)	[thread overview]
Message-ID: <alpine.LFD.1.00.0804291556550.2548@localhost.localdomain> (raw)
In-Reply-To: <20080428154524.GE7334@c2.user-mode-linux.org>

On Mon, 28 Apr 2008, Jeff Dike wrote:

> On Sat, Apr 26, 2008 at 06:01:12PM +0800, WANG Cong wrote:
>> > +	/*
>> > +	 * When the stub stops, we find the following values on the
>> > +	 * beginning of the stack:
>> > +	 * (long) return_value
>> > +	 * (long) offset to failed sycall data (0 if no error)
>> > +	 */
>> > +	ret = *((unsigned long *) stack);
>> 
>> 
>> I am afraid the value will be truncated on 64bit machine, since
>> 'ret' is 'int' while 'stack' points to an 'unsigned long'.
>> 
>> Is this expected?
>
> That's dubious, but I don't think it breaks anything.  On LE, *(int *)
> and *(long *) will give you the same answer, and the value here is an
> error code, which fits into 32 bits.

So it's safe here.

OK. Thanks!

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      reply	other threads:[~2008-04-29  7:58 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-25 17:56 [uml-devel] [PATCH 2/19] UML - Tidy stub management code Jeff Dike
2008-04-26 10:01 ` WANG Cong
2008-04-28 15:45   ` Jeff Dike
2008-04-29  7:57     ` WANG Cong [this message]

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