[3/6] target-arm: Implement MDCR_EL3.TDOSA and MDCR_EL2.TDOSA traps

Implement the traps to EL2 and EL3 controlled by the bits
MDCR_EL2.TDOSA MDCR_EL3.TDOSA. These can configurably trap
accesses to the "powerdown debug" registers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target-arm/cpu.h    | 12 ++++++++++++
 target-arm/helper.c | 23 ++++++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

On 05.02.2016 19:45, Peter Maydell wrote:
> Implement the traps to EL2 and EL3 controlled by the bits
> MDCR_EL2.TDOSA MDCR_EL3.TDOSA. These can configurably trap
> accesses to the "powerdown debug" registers.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Sergey Fedorov <serge.fdrv@gmail.com>

> ---
>  target-arm/cpu.h    | 12 ++++++++++++
>  target-arm/helper.c | 23 ++++++++++++++++++++++-
>  2 files changed, 34 insertions(+), 1 deletion(-)
>
> diff --git a/target-arm/cpu.h b/target-arm/cpu.h
> index 80391fa..d1d6886 100644
> --- a/target-arm/cpu.h
> +++ b/target-arm/cpu.h
> @@ -595,6 +595,18 @@ void pmccntr_sync(CPUARMState *env);
>  #define CPTR_TTA      (1U << 20)
>  #define CPTR_TFP      (1U << 10)
>  
> +#define MDCR_EPMAD    (1U << 21)
> +#define MDCR_EDAD     (1U << 20)
> +#define MDCR_SPME     (1U << 17)
> +#define MDCR_SDD      (1U << 16)
> +#define MDCR_TDRA     (1U << 11)
> +#define MDCR_TDOSA    (1U << 10)
> +#define MDCR_TDA      (1U << 9)
> +#define MDCR_TDE      (1U << 8)
> +#define MDCR_HPME     (1U << 7)
> +#define MDCR_TPM      (1U << 6)
> +#define MDCR_TPMCR    (1U << 5)
> +
>  #define CPSR_M (0x1fU)
>  #define CPSR_T (1U << 5)
>  #define CPSR_F (1U << 6)
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index 082701a..18e85fd 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -384,6 +384,24 @@ static CPAccessResult access_trap_aa32s_el1(CPUARMState *env,
>      return CP_ACCESS_TRAP_UNCATEGORIZED;
>  }
>  
> +/* Check for traps to "powerdown debug" registers, which are controlled
> + * by MDCR.TDOSA
> + */
> +static CPAccessResult access_tdosa(CPUARMState *env, const ARMCPRegInfo *ri,
> +                                   bool isread)
> +{
> +    int el = arm_current_el(env);
> +
> +    if (el < 2 && (env->cp15.mdcr_el2 & MDCR_TDOSA)
> +        && !arm_is_secure_below_el3(env)) {
> +        return CP_ACCESS_TRAP_EL2;
> +    }
> +    if (el < 3 && (env->cp15.mdcr_el3 & MDCR_TDOSA)) {
> +        return CP_ACCESS_TRAP_EL3;
> +    }
> +    return CP_ACCESS_OK;
> +}
> +
>  static void dacr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
>  {
>      ARMCPU *cpu = arm_env_get_cpu(env);
> @@ -3779,15 +3797,18 @@ static const ARMCPRegInfo debug_cp_reginfo[] = {
>      { .name = "OSLAR_EL1", .state = ARM_CP_STATE_BOTH,
>        .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 0, .opc2 = 4,
>        .access = PL1_W, .type = ARM_CP_NO_RAW,
> +      .accessfn = access_tdosa,
>        .writefn = oslar_write },
>      { .name = "OSLSR_EL1", .state = ARM_CP_STATE_BOTH,
>        .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 1, .opc2 = 4,
>        .access = PL1_R, .resetvalue = 10,
> +      .accessfn = access_tdosa,
>        .fieldoffset = offsetof(CPUARMState, cp15.oslsr_el1) },
>      /* Dummy OSDLR_EL1: 32-bit Linux will read this */
>      { .name = "OSDLR_EL1", .state = ARM_CP_STATE_BOTH,
>        .cp = 14, .opc0 = 2, .opc1 = 0, .crn = 1, .crm = 3, .opc2 = 4,
> -      .access = PL1_RW, .type = ARM_CP_NOP },
> +      .access = PL1_RW, .accessfn = access_tdosa,
> +      .type = ARM_CP_NOP },
>      /* Dummy DBGVCR: Linux wants to clear this on startup, but we don't
>       * implement vector catch debug events yet.
>       */