[U-Boot] [PATCH] bootm: flush cache on aligned region

[Lothar Waßmann]

Hi your name,

On Wed, 20 Dec 2017 09:12:28 -0800 your name wrote:
> From: Andrey Yurovsky <yurovsky at gmail.com>
> 
> bootm_load_os() uses flush_cache() on the region where the OS image is
> loaded however the OS image may be part of a FIT image and thereby may
> not be aligned with respect to the machine's cache lines. Give
> flush_cache() an aligned start of the region to avoid misalignment.
> 
> Signed-off-by: Andrey Yurovsky <yurovsky at gmail.com>
> ---
>  common/bootm.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/common/bootm.c b/common/bootm.c
> index adb12137c7..948807af25 100644
> --- a/common/bootm.c
> +++ b/common/bootm.c
> @@ -447,7 +447,10 @@ static int bootm_load_os(bootm_headers_t *images, unsigned long *load_end,
>  		bootstage_error(BOOTSTAGE_ID_DECOMP_IMAGE);
>  		return err;
>  	}
> -	flush_cache(load, ALIGN(*load_end - load, ARCH_DMA_MINALIGN));
> +
> +	ulong load_a = ALIGN(load, ARCH_DMA_MINALIGN);
> +
This is WRONG. ALIGN() only ever _increases_ the value passed to it, so
the first ARCH_DMA_MINALIGN - 1 bytes of the image may not be flushed
in the worst case.

> +	flush_cache(load_a, ALIGN(*load_end - load_a, ARCH_DMA_MINALIGN));
>  
>  	debug("   kernel loaded at 0x%08lx, end = 0x%08lx\n", load, *load_end);
>  	bootstage_mark(BOOTSTAGE_ID_KERNEL_LOADED);


Lothar Waßmann