Re: [Qemu-devel] [PATCH 04/24] target-arm: Log bad system register accesses with LOG_UNIMP

[Peter Crosthwaite <peter.crosthwaite@xilinx.com>]

On Wed, Jan 22, 2014 at 6:12 AM, Peter Maydell <peter.maydell@linaro.org> wrote:
> Log guest attempts to access unimplemented system registers via
> the LOG_UNIMP reporting mechanism (for both the 32 bit and 64 bit
> instruction sets). This is particularly useful for debugging
> problems where the guest is trying to use a system register that
> QEMU doesn't implement.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>

> ---
>  target-arm/translate-a64.c |  7 ++++++-
>  target-arm/translate.c     | 13 +++++++++++++
>  2 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
> index a808a88..e0f6765 100644
> --- a/target-arm/translate-a64.c
> +++ b/target-arm/translate-a64.c
> @@ -1121,7 +1121,12 @@ static void handle_sys(DisasContext *s, uint32_t insn, bool isread,
>                                                 crn, crm, op0, op1, op2));
>
>      if (!ri) {
> -        /* Unknown register */
> +        /* Unknown register; this might be a guest error or a QEMU
> +         * unimplemented feature.
> +         */
> +        qemu_log_mask(LOG_UNIMP, "%s access to unsupported AArch64 "
> +                      "system register op0:%d op1:%d crn:%d crm:%d op2:%d\n",
> +                      isread ? "read" : "write", op0, op1, crn, crm, op2);
>          unallocated_encoding(s);
>          return;
>      }
> diff --git a/target-arm/translate.c b/target-arm/translate.c
> index 8d240e1..59a206d 100644
> --- a/target-arm/translate.c
> +++ b/target-arm/translate.c
> @@ -6672,6 +6672,19 @@ static int disas_coproc_insn(CPUARMState * env, DisasContext *s, uint32_t insn)
>          return 0;
>      }
>
> +    /* Unknown register; this might be a guest error or a QEMU
> +     * unimplemented feature.
> +     */
> +    if (is64) {
> +        qemu_log_mask(LOG_UNIMP, "%s access to unsupported AArch32 "
> +                      "64 bit system register cp:%d opc1: %d crm:%d\n",
> +                      isread ? "read" : "write", cpnum, opc1, crm);
> +    } else {
> +        qemu_log_mask(LOG_UNIMP, "%s access to unsupported AArch32 "
> +                      "system register cp:%d opc1:%d crn:%d crm:%d opc2:%d\n",
> +                      isread ? "read" : "write", cpnum, opc1, crn, crm, opc2);
> +    }
> +
>      return 1;
>  }
>
> --
> 1.8.5
>
>