Re: [PULL 23/35] hw/intc: Rework Loongson LIOINTC

[Peter Maydell]

On Sun, 3 Jan 2021 at 21:11, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>
> From: Huacai Chen <chenhuacai@kernel.org>
>
> As suggested by Philippe Mathieu-Daudé, rework Loongson's liointc:
> 1, Move macro definitions to loongson_liointc.h;
> 2, Remove magic values and use macros instead;
> 3, Replace dead D() code by trace events.
>
> Suggested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Signed-off-by: Huacai Chen <chenhuacai@kernel.org>
> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Message-Id: <20201221110538.3186646-2-chenhuacai@kernel.org>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  include/hw/intc/loongson_liointc.h | 22 ++++++++++++++++++
>  hw/intc/loongson_liointc.c         | 36 +++++++++++++-----------------
>  2 files changed, 38 insertions(+), 20 deletions(-)
>  create mode 100644 include/hw/intc/loongson_liointc.h

Hi; Coverity complains about a possible array overrun
in this commit:


> @@ -40,13 +39,10 @@
>  #define R_IEN                   0x24
>  #define R_IEN_SET               0x28
>  #define R_IEN_CLR               0x2c
> -#define R_PERCORE_ISR(x)        (0x40 + 0x8 * x)
> +#define R_ISR_SIZE              0x8
> +#define R_START                 0x40
>  #define R_END                   0x64
>
> -#define TYPE_LOONGSON_LIOINTC "loongson.liointc"
> -DECLARE_INSTANCE_CHECKER(struct loongson_liointc, LOONGSON_LIOINTC,
> -                         TYPE_LOONGSON_LIOINTC)
> -
>  struct loongson_liointc {
>      SysBusDevice parent_obj;
>
> @@ -123,14 +119,13 @@ liointc_read(void *opaque, hwaddr addr, unsigned int 
> size)
>          goto out;
>      }
>
> -    /* Rest is 4 byte */
> +    /* Rest are 4 bytes */
>      if (size != 4 || (addr % 4)) {
>          goto out;
>      }
>
> -    if (addr >= R_PERCORE_ISR(0) &&
> -        addr < R_PERCORE_ISR(NUM_CORES)) {
> -        int core = (addr - R_PERCORE_ISR(0)) / 8;
> +    if (addr >= R_START && addr < R_END) {
> +        int core = (addr - R_START) / R_ISR_SIZE;

R_END is 0x64 and R_START is 0x40, so if addr is 0x60
then addr - R_START is 0x32 and so core here is 4.
However p->per_core_isr[] only has 4 entries, so this will
be off the end of the array.

This is CID 1438965.

>          r = p->per_core_isr[core];
>          goto out;
>      }

> -    if (addr >= R_PERCORE_ISR(0) &&
> -        addr < R_PERCORE_ISR(NUM_CORES)) {
> -        int core = (addr - R_PERCORE_ISR(0)) / 8;
> +    if (addr >= R_START && addr < R_END) {
> +        int core = (addr - R_START) / R_ISR_SIZE;
>          p->per_core_isr[core] = value;
>          goto out;
>      }

Same thing here, CID 1438967.

thanks
-- PMM