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-König 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. Best regards Uwe [1] http://thread.gmane.org/gmane.linux.ports.arm.kernel/36547/focus=36588 -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
