Re: [Qemu-devel] [PATCH for-4.1] hw/ssi/xilinx_spips: Avoid variable length array

[Alistair Francis]

On Thu, Mar 28, 2019 at 8:39 AM Peter Maydell <address@hidden> wrote:
>
> In the stripe8() function we use a variable length array; however
> we know that the maximum length required is MAX_NUM_BUSSES. Use
> a fixed-length array and an assert instead.
>
> Signed-off-by: Peter Maydell <address@hidden>

Reviewed-by: Alistair Francis <address@hidden>

Who's tree should this go through?

Alistair

> ---
>  hw/ssi/xilinx_spips.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/hw/ssi/xilinx_spips.c b/hw/ssi/xilinx_spips.c
> index 16f88f74029..c615058cc1b 100644
> --- a/hw/ssi/xilinx_spips.c
> +++ b/hw/ssi/xilinx_spips.c
> @@ -429,12 +429,14 @@ static void xlnx_zynqmp_qspips_reset(DeviceState *d)
>
>  static inline void stripe8(uint8_t *x, int num, bool dir)
>  {
> -    uint8_t r[num];
> -    memset(r, 0, sizeof(uint8_t) * num);
> +    uint8_t r[MAX_NUM_BUSSES];
>      int idx[2] = {0, 0};
>      int bit[2] = {0, 7};
>      int d = dir;
>
> +    assert(num <= MAX_NUM_BUSSES);
> +    memset(r, 0, sizeof(uint8_t) * num);
> +
>      for (idx[0] = 0; idx[0] < num; ++idx[0]) {
>          for (bit[0] = 7; bit[0] >= 0; bit[0]--) {
>              r[idx[!d]] |= x[idx[d]] & 1 << bit[d] ? 1 << bit[!d] : 0;
> --
> 2.20.1
>
>