Re: [Qemu-devel] [PATCH v5 10/33] target-arm: add non-secure Translation Block flag

[Peter Maydell]

On 30 September 2014 22:49, Greg Bellows <address@hidden> wrote:
> From: Sergey Fedorov <address@hidden>
>
> This patch is based on idea found in patch at
> git://github.com/jowinter/qemu-trustzone.git
> f3d955c6c0ed8c46bc0eb10b634201032a651dd2 by
> Johannes Winter <address@hidden>.
>
> This flag prevents QEMU from executing TCG code generated for other CPU
> security state. It also allows to generate different TCG code depending on
> CPU secure state.

This doesn't quite seem to line up with the code:
the commit message says the flag is for the CPU's
current security state, but the code is using the
"which register bank" setting.

> Signed-off-by: Sergey Fedorov <address@hidden>
> Signed-off-by: Fabian Aggeler <address@hidden>
> Signed-off-by: Greg Bellows <address@hidden>
>
> ----------
> v4 -> v5
> - Merge changes
> - Fixed issue where TB secure state flag was incorrectly being set based on
>   secure state rather than NS setting.  This caused an issue where monitor 
> mode
>   MRC/MCR accesses were always secure rather than being based on NS bit
>   setting.
> - Added separate 64/32 TB secure state flags
> - Unconditionalized the setting of the DC ns bit
> - Removed IS_NS macro and replaced with direct usage.
> ---
>  target-arm/cpu.h           | 14 ++++++++++++++
>  target-arm/translate-a64.c |  1 +
>  target-arm/translate.c     |  1 +
>  target-arm/translate.h     |  1 +
>  4 files changed, 17 insertions(+)
>
> diff --git a/target-arm/cpu.h b/target-arm/cpu.h
> index c58fdf5..1700676 100644
> --- a/target-arm/cpu.h
> +++ b/target-arm/cpu.h
> @@ -1528,6 +1528,8 @@ static inline bool arm_singlestep_active(CPUARMState 
> *env)
>   */
>  #define ARM_TBFLAG_XSCALE_CPAR_SHIFT 20
>  #define ARM_TBFLAG_XSCALE_CPAR_MASK (3 << ARM_TBFLAG_XSCALE_CPAR_SHIFT)
> +#define ARM_TBFLAG_NS_SHIFT         22
> +#define ARM_TBFLAG_NS_MASK          (1 << ARM_TBFLAG_NS_SHIFT)
>
>  /* Bit usage when in AArch64 state */
>  #define ARM_TBFLAG_AA64_EL_SHIFT    0
> @@ -1538,6 +1540,8 @@ static inline bool arm_singlestep_active(CPUARMState 
> *env)
>  #define ARM_TBFLAG_AA64_SS_ACTIVE_MASK (1 << ARM_TBFLAG_AA64_SS_ACTIVE_SHIFT)
>  #define ARM_TBFLAG_AA64_PSTATE_SS_SHIFT 4
>  #define ARM_TBFLAG_AA64_PSTATE_SS_MASK (1 << ARM_TBFLAG_AA64_PSTATE_SS_SHIFT)
> +#define ARM_TBFLAG_AA64_NS_SHIFT    5
> +#define ARM_TBFLAG_AA64_NS_MASK     (1 << ARM_TBFLAG_AA64_NS_SHIFT)
>
>  /* some convenience accessor macros */
>  #define ARM_TBFLAG_AARCH64_STATE(F) \
> @@ -1572,6 +1576,10 @@ static inline bool arm_singlestep_active(CPUARMState 
> *env)
>      (((F) & ARM_TBFLAG_AA64_SS_ACTIVE_MASK) >> 
> ARM_TBFLAG_AA64_SS_ACTIVE_SHIFT)
>  #define ARM_TBFLAG_AA64_PSTATE_SS(F) \
>      (((F) & ARM_TBFLAG_AA64_PSTATE_SS_MASK) >> 
> ARM_TBFLAG_AA64_PSTATE_SS_SHIFT)
> +#define ARM_TBFLAG_NS(F) \
> +    (((F) & ARM_TBFLAG_NS_MASK) >> ARM_TBFLAG_NS_SHIFT)
> +#define ARM_TBFLAG_AA64_NS(F) \
> +    (((F) & ARM_TBFLAG_AA64_NS_MASK) >> ARM_TBFLAG_AA64_NS_SHIFT)
>
>  static inline void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
>                                          target_ulong *cs_base, int *flags)
> @@ -1605,6 +1613,9 @@ static inline void cpu_get_tb_cpu_state(CPUARMState 
> *env, target_ulong *pc,
>                  *flags |= ARM_TBFLAG_AA64_PSTATE_SS_MASK;
>              }
>          }
> +        if (!(USE_SECURE_REG(env))) {
> +            *flags |= ARM_TBFLAG_AA64_NS_MASK;
> +        }

What's this for? If we're in AArch64 mode then we know that
EL3 (if it exists) must also be AArch64, and so USE_SECURE_REG
always returns false...

>      } else {
>          int privmode;
>          *pc = env->regs[15];
> @@ -1621,6 +1632,9 @@ static inline void cpu_get_tb_cpu_state(CPUARMState 
> *env, target_ulong *pc,
>          if (privmode) {
>              *flags |= ARM_TBFLAG_PRIV_MASK;
>          }
> +        if (!(USE_SECURE_REG(env))) {
> +            *flags |= ARM_TBFLAG_NS_MASK;
> +        }
>          if (env->vfp.xregs[ARM_VFP_FPEXC] & (1 << 30)
>              || arm_el_is_aa64(env, 1)) {
>              *flags |= ARM_TBFLAG_VFPEN_MASK;
> diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
> index f53dc0f..dfc8c58 100644
> --- a/target-arm/translate-a64.c
> +++ b/target-arm/translate-a64.c
> @@ -10926,6 +10926,7 @@ void gen_intermediate_code_internal_a64(ARMCPU *cpu,
>  #if !defined(CONFIG_USER_ONLY)
>      dc->user = (ARM_TBFLAG_AA64_EL(tb->flags) == 0);
>  #endif
> +    dc->ns = ARM_TBFLAG_AA64_NS(tb->flags);
>      dc->cpacr_fpen = ARM_TBFLAG_AA64_FPEN(tb->flags);
>      dc->vec_len = 0;
>      dc->vec_stride = 0;
> diff --git a/target-arm/translate.c b/target-arm/translate.c
> index 3f3ddfb..5e1d677 100644
> --- a/target-arm/translate.c
> +++ b/target-arm/translate.c
> @@ -10958,6 +10958,7 @@ static inline void 
> gen_intermediate_code_internal(ARMCPU *cpu,
>  #if !defined(CONFIG_USER_ONLY)
>      dc->user = (ARM_TBFLAG_PRIV(tb->flags) == 0);
>  #endif
> +    dc->ns = ARM_TBFLAG_NS(tb->flags);
>      dc->cpacr_fpen = ARM_TBFLAG_CPACR_FPEN(tb->flags);
>      dc->vfp_enabled = ARM_TBFLAG_VFPEN(tb->flags);
>      dc->vec_len = ARM_TBFLAG_VECLEN(tb->flags);
> diff --git a/target-arm/translate.h b/target-arm/translate.h
> index 85c6f9d..4f9892b 100644
> --- a/target-arm/translate.h
> +++ b/target-arm/translate.h
> @@ -20,6 +20,7 @@ typedef struct DisasContext {
>  #if !defined(CONFIG_USER_ONLY)
>      int user;
>  #endif
> +    bool ns;

This could use a brief comment explaining what it indicates.

>      bool cpacr_fpen; /* FP enabled via CPACR.FPEN */
>      bool vfp_enabled; /* FP enabled via FPSCR.EN */
>      int vec_len;
> --
> 1.8.3.2