From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: defining ZRELADDR as PHYS_OFFSET + TEXT_OFFSET
Date: Thu, 28 Jan 2010 00:15:23 +0000 [thread overview]
Message-ID: <20100128001523.GA608@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20100127101228.GA17421@pengutronix.de>
On Wed, Jan 27, 2010 at 11:12:28AM +0100, Uwe Kleine-K?nig wrote:
> Hello,
>
> currently all platforms need to define zreladdr-y in
> arch/arm/mach-$mach/Makefile.boot and PHYS_OFFSET (in
> arch/arm/mach-$mach/include/mach/memory.h).
>
> Constraints for these are:
>
> TEXTADDR = PAGE_OFFSET + TEXT_OFFSET
> __virt_to_phys(virt) = virt - PAGE_OFFSET + PHYS_OFFSET (at least for
> "small" virtual addresses)
> ZRELADDR = __virt_to_phys(TEXTADDR)
>
> (The equallity for __virt_to_phys only holds "normaly" according to
> http://lists.arm.linux.org.uk/lurker/message/20010723.185051.94ce743c.en.html.
> In practice it holds for addresses of the first bank of RAM which is
> enough for the purposes of this mail.)
>
> So we can deduce ZRELADDR = PHYS_OFFSET + TEXT_OFFSET.
>
> Is there something I missed or is it possible to get rid of zreladdr-y
> in .../Makefile.boot and define it according to the equation above?
You'd need to find some way to get PHYS_OFFSET out of the C code
into the makefile. With all sorts of stuff going on in various
platforms memory.h files, that doesn't look simple.
next prev parent reply other threads:[~2010-01-28 0:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-27 10:12 defining ZRELADDR as PHYS_OFFSET + TEXT_OFFSET Uwe Kleine-König
2010-01-28 0:15 ` Russell King - ARM Linux [this message]
2010-02-01 1:24 ` George G. Davis
2010-02-01 8:49 ` Uwe Kleine-König
2010-02-05 8:26 ` George G. Davis
2010-02-05 9:10 ` Uwe Kleine-König
2010-02-05 14:14 ` George G. Davis
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