Re: [Qemu-devel] [PATCH v5 05/33] target-arm: make arm_current_pl() return PL3

[Peter Maydell]

On 30 September 2014 22:49, Greg Bellows <address@hidden> wrote:
> From: Fabian Aggeler <address@hidden>
>
> Make arm_current_pl() return PL3 for secure PL1 and monitor mode.
> Increase MMU modes since mmu_index is directly infered from arm_
> current_pl(). Changes assertion in arm_el_is_aa64() to allow EL3.
>
> Signed-off-by: Fabian Aggeler <address@hidden>
> Signed-off-by: Greg Bellows <address@hidden>
> ---
>  target-arm/cpu.h | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/target-arm/cpu.h b/target-arm/cpu.h
> index 101d139..c000716 100644
> --- a/target-arm/cpu.h
> +++ b/target-arm/cpu.h
> @@ -100,7 +100,7 @@ typedef uint32_t ARMReadCPFunc(void *opaque, int cp_info,
>
>  struct arm_boot_info;
>
> -#define NB_MMU_MODES 2
> +#define NB_MMU_MODES 4
>
>  /* We currently assume float and double are IEEE single and double
>     precision respectively.
> @@ -753,7 +753,6 @@ static inline int arm_feature(CPUARMState *env, int 
> feature)
>      return (env->features & (1ULL << feature)) != 0;
>  }
>
> -

Stray whitespace change.

>  /* Return true if exception level below EL3 is in secure state */
>  static inline bool arm_is_secure_below_el3(CPUARMState *env)
>  {
> @@ -794,11 +793,12 @@ static inline bool arm_is_secure(CPUARMState *env)
>  /* Return true if the specified exception level is running in AArch64 state. 
> */
>  static inline bool arm_el_is_aa64(CPUARMState *env, int el)
>  {
> -    /* We don't currently support EL2 or EL3, and this isn't valid for EL0
> +    /* We don't currently support EL2, and this isn't valid for EL0
>       * (if we're in EL0, is_a64() is what you want, and if we're not in EL0
>       * then the state of EL0 isn't well defined.)
>       */
> -    assert(el == 1);
> +    assert(el == 1 || el == 3);
> +
>      /* AArch64-capable CPUs always run with EL1 in AArch64 mode. This
>       * is a QEMU-imposed simplification which we may wish to change later.
>       * If we in future support EL2 and/or EL3, then the state of lower

> @@ -990,9 +990,12 @@ static inline int arm_current_el(CPUARMState *env)
>
>      if ((env->uncached_cpsr & 0x1f) == ARM_CPU_MODE_USR) {
>          return 0;
> +    } else if (arm_is_secure(env)) {
> +        /* Secure PL1 and monitor mode are mapped to PL3 */
> +        return 3;

This isn't correct. Secure privileged !Mon AArch32 modes are only
EL3 if EL3 is AArch32. If EL3 is AArch64 then the !Mon AArch32
modes are EL1.

>      }
> -    /* We don't currently implement the Virtualization or TrustZone
> -     * extensions, so PL2 and PL3 don't exist for us.
> +    /* We currently do not implement the Virtualization extensions, so PL2 
> does
> +     * not exist for us.
>       */
>      return 1;

Now that we've added the complications for handling secure mode,
we might as well also have the trivial code for Hyp too. So
that means the function looks something like:

    if (env->aarch64) {
        return extract32(env->pstate, 2, 2);
    }

    switch (env->uncached_cpsr & CPSR_M) {
    case ARM_CPU_MODE_USR:
        return 0;
    case ARM_CPU_MODE_HYP:
        return 2;
    case ARM_CPU_MODE_MON:
        return 3;
    default:
        if (arm_is_secure(env) && !arm_el_is_aa64(env, 3)) {
            /* If EL3 is 32-bit then all secure privileged modes run in EL3 */
            return 3;
        }
        return 1;
    }

thanks
-- PMM