[PATCH] Fix data abort caused by mis-aligning fit data in

[Tom Rini]

On Fri, Jul 24, 2020 at 05:19:39AM +0000, Reuben Dowle wrote:

> Attempting to place device tree immediately after an image in memory can lead
> to mis-aligned data accesses if that image size is not divisible by the
> alignment requirements of the architecture.
> 
> Data aborts caused by this were observed on a custom Marvel A388 based system,
> where the image was a uboot FIT file. The total size varies depending on the
> uboot device tree size, which does not always lead to correct alignment.
> 
> Signed-off-by: Reuben Dowle <reuben.dowle at 4rf.com>
> ---
>  common/spl/spl_fit.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
> index 365104f..d221075 100644
> --- a/common/spl/spl_fit.c
> +++ b/common/spl/spl_fit.c
> @@ -349,9 +349,9 @@ static int spl_fit_append_fdt(struct spl_image_info *spl_image,
>  
>  	/*
>  	 * Use the address following the image as target address for the
> -	 * device tree.
> +	 * device tree. Ensure that address is appropriately aligned.
>  	 */
> -	image_info.load_addr = spl_image->load_addr + spl_image->size;
> +	image_info.load_addr = ALIGN(spl_image->load_addr + spl_image->size, ARCH_DMA_MINALIGN);
>  
>  	/* Figure out which device tree the board wants to use */
>  	node = spl_fit_get_image_node(fit, images, FIT_FDT_PROP, index++);

Sorry for the late reply here.  While we do need to ensure that the
device tree is aligned, the documented alignment requirement for all
platforms is 8 byte, so we should document and use that here in case
future platforms require a higher alignment.  Thanks!

-- 
Tom
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