[U-Boot] [PATCH 081/126] x86: Correct mrccache find_next_mrc_cache() calculation

[Bin Meng]

Hi Simon,

On Wed, Sep 25, 2019 at 10:59 PM Simon Glass <sjg at chromium.org> wrote:
>
> This should take account of the end of the new cache record since a record
> cannot extend beyond the end of the flash region. This problem was not
> seen before due to the alignment of the relatively small amount of MRC
> data.
>
> But with apollolake the MRC data is about 45KB, even if most of it is
> zeroes.
>
> Fix this bug and update the parameter name to be less confusing.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
>  arch/x86/lib/mrccache.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/lib/mrccache.c b/arch/x86/lib/mrccache.c
> index 33bb52039bd..e286bdf1b30 100644
> --- a/arch/x86/lib/mrccache.c
> +++ b/arch/x86/lib/mrccache.c
> @@ -86,15 +86,16 @@ struct mrc_data_container *mrccache_find_current(struct mrc_region *entry)
>   * @return next cache entry if found, NULL if we got to the end
>   */
>  static struct mrc_data_container *find_next_mrc_cache(struct mrc_region *entry,
> -               struct mrc_data_container *cache)
> +               struct mrc_data_container *prev)
>  {
> +       struct mrc_data_container *cache;
>         ulong base_addr, end_addr;
>
>         base_addr = entry->base + entry->offset;
>         end_addr = base_addr + entry->length;
>
> -       cache = next_mrc_block(cache);
> -       if ((ulong)cache >= end_addr) {
> +       cache = next_mrc_block(prev);
> +       if ((ulong)cache + mrc_block_size(prev->data_size) > end_addr) {

This does not look good to me. Why adding the "next" cache position to
"prev" cache size? It should add the "next" cache size.

I agree there is an issue in missing check of boundary, but the check
should not happen here, but mrccache_update(), before writing to SPI
flash.

>                 /* Crossed the boundary */
>                 cache = NULL;
>                 debug("%s: no available entries found\n", __func__);
> --

Regards,
Bin