Re: [PATCH 07/15] hw/intc: sifive_plic: Improve robustness of the PLIC config parser

[Alistair Francis]

On Fri, Dec 2, 2022 at 12:15 AM Bin Meng <bmeng@tinylab.org> wrote:
>
> At present the PLIC config parser can only handle legal config string
> like "MS,MS". However if a config string like ",MS,MS,,MS,MS,," is
> given the parser won't get the correct configuration.
>
> This commit improves the config parser to make it more robust.
>
> Signed-off-by: Bin Meng <bmeng@tinylab.org>

Acked-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>
>  hw/intc/sifive_plic.c | 24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/hw/intc/sifive_plic.c b/hw/intc/sifive_plic.c
> index 3f6ffb1d70..5fd9a53569 100644
> --- a/hw/intc/sifive_plic.c
> +++ b/hw/intc/sifive_plic.c
> @@ -290,7 +290,7 @@ static void sifive_plic_reset(DeviceState *dev)
>   */
>  static void parse_hart_config(SiFivePLICState *plic)
>  {
> -    int addrid, hartid, modes;
> +    int addrid, hartid, modes, m;
>      const char *p;
>      char c;
>
> @@ -299,11 +299,13 @@ static void parse_hart_config(SiFivePLICState *plic)
>      p = plic->hart_config;
>      while ((c = *p++)) {
>          if (c == ',') {
> -            addrid += ctpop8(modes);
> -            modes = 0;
> -            hartid++;
> +            if (modes) {
> +                addrid += ctpop8(modes);
> +                hartid++;
> +                modes = 0;
> +            }
>          } else {
> -            int m = 1 << char_to_mode(c);
> +            m = 1 << char_to_mode(c);
>              if (modes == (modes | m)) {
>                  error_report("plic: duplicate mode '%c' in config: %s",
>                               c, plic->hart_config);
> @@ -314,8 +316,9 @@ static void parse_hart_config(SiFivePLICState *plic)
>      }
>      if (modes) {
>          addrid += ctpop8(modes);
> +        hartid++;
> +        modes = 0;
>      }
> -    hartid++;
>
>      plic->num_addrs = addrid;
>      plic->num_harts = hartid;
> @@ -326,11 +329,16 @@ static void parse_hart_config(SiFivePLICState *plic)
>      p = plic->hart_config;
>      while ((c = *p++)) {
>          if (c == ',') {
> -            hartid++;
> +            if (modes) {
> +                hartid++;
> +                modes = 0;
> +            }
>          } else {
> +            m = char_to_mode(c);
>              plic->addr_config[addrid].addrid = addrid;
>              plic->addr_config[addrid].hartid = hartid;
> -            plic->addr_config[addrid].mode = char_to_mode(c);
> +            plic->addr_config[addrid].mode = m;
> +            modes |= (1 << m);
>              addrid++;
>          }
>      }
> --
> 2.34.1
>
>