Re: [PATCH 1/7] at91: add test commamd to emulate bootrom boot

From: Sascha Hauer <s.hauer@pengutronix.de>
To: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH 1/7] at91: add test commamd to emulate bootrom boot
Date: Sun, 20 Jan 2013 10:41:56 +0100	[thread overview]
Message-ID: <20130120094156.GO1906@pengutronix.de> (raw)
In-Reply-To: <20130119163208.GB26329@game.jcrosoft.org>

On Sat, Jan 19, 2013 at 05:32:08PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > > > > +	shutdown_barebox();
> > > > > +
> > > > > +	__asm__ __volatile__(
> > > > > +		"mov pc, %0\n"
> > > > > +		:
> > > > > +		: "r"(jump)
> > > > > +		:);
> > > > 
> > > > Is this inline assemble needed? Why not
> > > > 
> > > > 	void (*jump)(void);
> > > > 
> > > > 	jump();
> > > jump can be NULL
> > 
> > But that's not a reason for inline assembly.
> except if use call we get a NULL exception

You won't get a NULL pointer exception when the MMU is disabled (which
is the case after shutdown_basebox()), no matter which method you choose
to jump to 0x0.

Sascha

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