[PATCH 09/14] ARM: i.MX: add imx6_can_access_tzasc()

[Marco Felsch]

On 25-06-27, Sascha Hauer wrote:
> On ARMv7 there is no direct way to detect if we are in the secure or non
> secure world. Add a imx6_can_access_tzasc() for this purpose. When
> accessing the TZASC triggers a data abort then we are in the non secure
> world. This function can be used later to detect if we have to load
       ^
because OP-TEE configures the TZASC access policy to secure-world R/W. ?

Keep in mind that this test will fail if a downstream/buggy OP-TEE
doesn't configure the CSU correctly. Fingers crossed that this never
will never happen.

> OP-TEE or not.
> 
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
>  arch/arm/mach-imx/tzasc.c | 16 ++++++++++++++++
>  include/mach/imx/tzasc.h  |  1 +
>  2 files changed, 17 insertions(+)
> 
> diff --git a/arch/arm/mach-imx/tzasc.c b/arch/arm/mach-imx/tzasc.c
> index ed20ad8803a2e91b67b5d8c3ab1a4265c4228ec7..63f01cbaa6d4a8fbf47b9683ca840ee64f908cfc 100644
> --- a/arch/arm/mach-imx/tzasc.c
> +++ b/arch/arm/mach-imx/tzasc.c
> @@ -13,6 +13,8 @@
>  #include <linux/sizes.h>
>  #include <mach/imx/imx8m-regs.h>
>  #include <io.h>
> +#include <abort.h>
> +#include <asm/barebox-arm.h>
>  
>  /*******************************************************************************
>   *                         TZC380 defines
> @@ -329,6 +331,20 @@ bool imx6ul_tzc380_is_bypassed(void)
>  	return !(readl(&gpr[9]) & MX6_GPR_TZASC1_EN);
>  }
>  
> +bool imx6_can_access_tzasc(void)
> +{
> +	if (!IS_ENABLED(CONFIG_ARM_EXCEPTIONS_PBL))
> +		panic("%s only works with CONFIG_ARM_EXCEPTIONS_PBL\n", __func__);
> +
> +	arm_pbl_init_exceptions();

Can't we do that within the imx*_cpu_lowlevel_init?

Regards,
  Marco

> +
> +	data_abort_mask();
> +
> +	readl(IOMEM(MX6_TZASC1_BASE));
> +
> +	return !data_abort_unmask();
> +}
> +
>  void imx8m_tzc380_init(void)
>  {
>  	u32 __iomem *gpr = IOMEM(MX8M_IOMUXC_GPR_BASE_ADDR);
> diff --git a/include/mach/imx/tzasc.h b/include/mach/imx/tzasc.h
> index 0fbcdc2150e63864366a8dddeed2d1b97685903d..ca85704a8f459ab6e0cdc975940d855929f3d6f7 100644
> --- a/include/mach/imx/tzasc.h
> +++ b/include/mach/imx/tzasc.h
> @@ -10,6 +10,7 @@ void imx6q_tzc380_early_ns_region1(void);
>  void imx6ul_tzc380_early_ns_region1(void);
>  bool imx6q_tzc380_is_bypassed(void);
>  bool imx6ul_tzc380_is_bypassed(void);
> +bool imx6_can_access_tzasc(void);
>  void imx8m_tzc380_init(void);
>  bool imx8m_tzc380_is_enabled(void);
>  
> 
> -- 
> 2.39.5
> 
> 
>