[U-Boot] [PATCH 1/6] sniper: Move PXE file address to a viable location

[Tom Rini]

On Sat, Mar 26, 2016 at 12:19:59PM +0100, Paul Kocialkowski wrote:
> This moves the PXE file address out of the bounds of the U-Boot image (which is
> loaded at 0x80100000).
> 
> This also moves the ramdisk address to a better-looking aligned location.
> 
> Signed-off-by: Paul Kocialkowski <contact at paulk.fr>
> ---
>  include/configs/sniper.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/configs/sniper.h b/include/configs/sniper.h
> index 171a8c4..2598af1 100644
> --- a/include/configs/sniper.h
> +++ b/include/configs/sniper.h
> @@ -243,8 +243,8 @@
>  	"loadaddr=0x82000000\0" \
>  	"fdt_addr_r=0x88000000\0" \
>  	"fdtaddr=0x88000000\0" \
> -	"ramdisk_addr_r=0x88080000\0" \
> -	"pxefile_addr_r=0x80100000\0" \
> +	"ramdisk_addr_r=0x84000000\0" \
> +	"pxefile_addr_r=0x86000000\0" \
>  	"scriptaddr=0x80000000\0" \
>  	"bootm_size=0x10000000\0" \
>  	"boot_mmc_dev=0\0" \

I strongly discourage these locations.  Quoting myself from
ti_armv7_common.h:
/*
 * We setup defaults based on constraints from the Linux kernel, which should
 * also be safe elsewhere.  We have the default load at 32MB into DDR (for
 * the kernel), FDT above 128MB (the maximum location for the end of the
 * kernel), and the ramdisk 512KB above that (allowing for hopefully never
 * seen large trees).  We say all of this must be within the first 256MB
 * as that will normally be within the kernel lowmem and thus visible via
 * bootm_size and we only run on platforms with 256MB or more of memory.
 */

Now, have you actually run into a problem with overwriting U-Boot?
Since U-Boot will run-time relocate, this shouldn't be a problem in
practice?  The minor games we play with locations here are due to Falcon
Mode where the BSS in question here is the one for SPL and we don't want
those two to conflict.

-- 
Tom
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