From: Andreas Schwab <schwab@suse.de>
To: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: libc-alpha@sourceware.org, libc-alpha@sources.redhat.com,
       linux-kernel@vger.kernel.org
Subject: Re: Linux i386 clone(): %ebx 'frobbing' ?
References: <20080215184228.GA6687@ubuntu> <jewsp69e5t.fsf@sykes.suse.de>
	<20080215230722.GA8012@ubuntu>
Date: Sat, 16 Feb 2008 00:28:11 +0100
In-Reply-To: <20080215230722.GA8012@ubuntu> (Ahmed S. Darwish's message of
	"Sat\, 16 Feb 2008 01\:07\:22 +0200")
Message-ID: <jeir0pajg4.fsf@sykes.suse.de>
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"Ahmed S. Darwish" <darwish.07@gmail.com> writes:

> Hi Andreas,
>
> On Fri, Feb 15, 2008, Andreas Schwab wrote:
>> "Ahmed S. Darwish" <darwish.07@gmail.com> writes:
>> 
>> > I don't understand how the `fn' argument reached the child thread
>> > in the %ebx register. It's said in the comment that `fn' will be
>> > popped to child 'in the ebx frobbing below'. But what does that mean ?
>> 
>> See "popl %ebx" after "int $0x80".
>> 
>
> I hope I'm not misreading something obvious, but I can't find
> the code where FUNC(%esp) is stored in %ebx before %ebx value
> got pushed in the stack (and restored in above 'popl' statement).

It is stored in the new stack for the child, as explained in the
comment.  The parent has a different stack.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstra?e 5, 90409 N?rnberg, Germany
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