From: marek.vasut@gmail•com (Marek Vasut)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/2] ARM: Add Kconfig option to use mkimage -T kernel_noload
Date: Mon, 12 Mar 2012 18:42:59 +0100 [thread overview]
Message-ID: <201203121843.00025.marek.vasut@gmail.com> (raw)
In-Reply-To: <20120229205901.GR14173@pengutronix.de>
Dear Uwe Kleine-K?nig,
> On Wed, Feb 29, 2012 at 08:45:27PM +0000, Russell King - ARM Linux wrote:
> > On Wed, Feb 29, 2012 at 09:39:58PM +0100, Uwe Kleine-K?nig wrote:
> > > I'd bet your platform has cache support in the decompressor without
> > > knowing which platform you use. I suggest commenting out
> > >
> > > bl cache_on
> > >
> > > in arch/arm/boot/compressed/head.S to see the difference.
> > >
> > > How do you build the uImage containing the zImage? If you use the
> > >
> > > in-kernel uImage target booting that usually means:
> > > - move the zImage to ZRELADDR
> > > - jump into zImage
> > > - decompress zImage to somewhere else
> > > - move decompressed image to ZRELADDR
> > > - jump to ZRELADDR
> > >
> > > That is you have two relocations because the first location for sure
> > > conflicts with the decompressed image.
> >
> > Actually, we do this slightly differently nowadays. Inside zImage:
> > - if zImage location conflicts, move the decompressed data
>
> s/de//
>
> > and decompressor to another location
> >
> > - decompress zImage to ZRELADDR
> > - jump to ZRELADDR
> >
> > That reduces the size required for copying. Of course, that copy can
> > (as it's always been the case) be totally eliminated by ensuring that
> > you load the zImage out of the way of the decompressed image.
> >
> > So, really, comparing a standard uImage produced by the standard kernel
> > with gzipped Image is far from a fair comparison. And that's actually
> > another argument for getting rid of the uImage target... it may make
> > people think a bit about what they're doing rather than accepting
> > whatever default location someone else chose for their kernel.
>
> I'm all in favour to remove the uImage target because back in 2007 we
> already had a similar discussion[1]. (Back then I still thought that
> improving the uImage support would be a good idea.)
>
> That said I think *in general* having support for U-Boot in the kernel
> is fine because I think U-Boot is the bootloader used most. But if you
> need some Kconfig settings or more than one Makefile target I think just
> building an Image or zImage and doing the U-Boot wrapping without the
> help of Linux' build system is preferable.
I believe eventually everyone will converge to having this option enabled.
Therefore this config option will just be always on and can be squashed away.
>
> Best regards
> Uwe
>
> [1] http://thread.gmane.org/gmane.linux.ports.arm.kernel/36547/focus=36588
Best regards,
Marek Vasut
next prev parent reply other threads:[~2012-03-12 17:42 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-29 0:03 [PATCH 1/2] ARM: Add Kconfig option to use mkimage -T kernel_noload Stephen Warren
2012-02-29 0:03 ` [PATCH 2/2] ARM: tegra: Add zreladdr etc to Makefile.boot for Tegra30 Stephen Warren
2012-02-29 12:29 ` [PATCH 1/2] ARM: Add Kconfig option to use mkimage -T kernel_noload Jean-Christophe PLAGNIOL-VILLARD
2012-02-29 16:58 ` Stephen Warren
2012-02-29 18:14 ` Jean-Christophe PLAGNIOL-VILLARD
2012-02-29 18:33 ` Tim Bird
2012-02-29 18:50 ` Jean-Christophe PLAGNIOL-VILLARD
2012-03-12 17:40 ` Marek Vasut
2012-03-12 17:44 ` Jean-Christophe PLAGNIOL-VILLARD
2012-02-29 19:12 ` Uwe Kleine-König
2012-02-29 19:17 ` Stephen Warren
2012-02-29 19:44 ` Uwe Kleine-König
2012-02-29 19:59 ` Stephen Warren
2012-02-29 20:12 ` Andre Renaud
2012-02-29 20:16 ` Stephen Warren
2012-02-29 20:19 ` Russell King - ARM Linux
2012-02-29 20:25 ` Andre Renaud
2012-02-29 20:29 ` Russell King - ARM Linux
2012-02-29 20:39 ` Uwe Kleine-König
2012-02-29 20:45 ` Russell King - ARM Linux
2012-02-29 20:59 ` Uwe Kleine-König
2012-03-01 4:55 ` Jean-Christophe PLAGNIOL-VILLARD
2012-03-12 17:42 ` Marek Vasut [this message]
2012-02-29 21:27 ` Stephen Warren
2012-02-29 22:28 ` Andre Renaud
2012-02-29 20:30 ` Uwe Kleine-König
2012-02-29 23:53 ` Ryan Mallon
2012-03-12 17:44 ` Marek Vasut
2012-03-01 15:34 ` Mark Brown
2012-03-01 17:01 ` Stephen Warren
2012-03-05 4:21 ` Olof Johansson
2012-03-05 20:29 ` Nicolas Pitre
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