[PATCH] lib: sbi: Check pmp index for overflow before programming

[Bin Meng]

On Thu, Dec 29, 2022 at 10:51 PM Himanshu Chauhan
<hchauhan at ventanamicro.com> wrote:
>
> Check the current pmp index if it overflows the number of
> pmp entries present. If so, skip the programming but
> print debug information about the region, domain and
> the last index of pmp programmed.
>
> Signed-off-by: Himanshu Chauhan <hchauhan at ventanamicro.com>
> ---
>  lib/sbi/sbi_hart.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> index 5447c52..2782c0d 100644
> --- a/lib/sbi/sbi_hart.c
> +++ b/lib/sbi/sbi_hart.c
> @@ -313,9 +313,17 @@ int sbi_hart_pmp_configure(struct sbi_scratch *scratch)
>                         pmp_flags |= PMP_L;
>
>                 pmp_addr =  reg->base >> PMP_SHIFT;
> -               if (pmp_gran_log2 <= reg->order && pmp_addr < pmp_addr_max)
> +               if (pmp_gran_log2 <= reg->order && pmp_addr < pmp_addr_max) {
> +                       if (pmp_idx+1 >= pmp_count) {

This check is meaningless. There is already a check at the beginning
of the loop:

                if (pmp_count <= pmp_idx)
                        break;

> +                               sbi_printf("Cannot program pmp region: 0x%lx (order: 0x%lx) for domain %s.\n",
> +                                          reg->base, reg->order, dom->name);
> +                               sbi_printf("Reason: No free PMP entry left. "
> +                                          "Number of PMP entries: %d Last PMP Index written: %d\n",
> +                                          pmp_count, pmp_idx);
> +                               break;
> +                       }
>                         pmp_set(pmp_idx++, pmp_flags, reg->base, reg->order);
> -               else {
> +               } else {
>                         sbi_printf("Can not configure pmp for domain %s", dom->name);
>                         sbi_printf(" because memory region address %lx or size %lx is not in range\n",
>                                     reg->base, reg->order);
> --

Regards,
Bin