[Pdbg] [PATCH v1] sbefifo: fix sbefifo_register_get with multiple registers

[Joel Stanley]

On Fri, 12 Nov 2021 at 07:10, Nicholas Piggin <npiggin at gmail.com> wrote:
>
> sbefifo_register_get_pull is not indexing the result buffer correctly
> for > 1 returned register.
>
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> ---
>  libsbefifo/cmd_register.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/libsbefifo/cmd_register.c b/libsbefifo/cmd_register.c
> index 6c3f336..1e74b6e 100644
> --- a/libsbefifo/cmd_register.c
> +++ b/libsbefifo/cmd_register.c
> @@ -57,6 +57,7 @@ static int sbefifo_register_get_push(uint8_t core_id, uint8_t thread_id, uint8_t
>  static int sbefifo_register_get_pull(uint8_t *buf, uint32_t buflen, uint8_t reg_count, uint64_t **value)
>  {
>         uint32_t i;
> +       uint32_t *b = (uint32_t *)buf;
>
>         if (buflen != reg_count * 8)
>                 return EPROTO;
> @@ -68,8 +69,8 @@ static int sbefifo_register_get_pull(uint8_t *buf, uint32_t buflen, uint8_t reg_
>         for (i=0; i<reg_count; i++) {
>                 uint32_t val1, val2;
>
> -               val1 = be32toh(*(uint32_t *) &buf[i*4]);
> -               val2 = be32toh(*(uint32_t *) &buf[i*4+4]);
> +               val1 = be32toh(b[i*2]);
> +               val2 = be32toh(b[i*2+1]);

Just to clarify, this is what the code was doing before:

               val1 = be32toh(b[i]);
               val2 = be32toh(b[i + 1]);

Which would read out from the buffer:

value = 0 | 1
value = 1 | 2
value = 2 | 3

And your fix is to add i*2:

value = 0 | 1
value = 2 | 3
value = 4 | 5

Looks good to me!

Reviewed-by: Joel Stanley <joel at jms.id.au>


>
>                 (*value)[i] = ((uint64_t)val1 << 32) | (uint64_t)val2;
>         }
> --
> 2.23.0
>
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