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Can the linux  boot up without arm-trusted-firmware if the trustzone is not necessary ?

Jorney

Hi experts,

     I am trying to boot the linux by my bootloader which is running on EL3 level.(switch to EL1 when I jump to the kernel)

     The trustzone is not necessay for me, so I don't want to use it.

     However, I'm comfused if the arm-trusted-firmware is needed?

     Some boards like Juno and Hikey  have used the arm-trusted-firmware .   

Regards,

Jorney

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  • 0 Arm Employee Badge in reply to Jorney

    Of course, any software could be secure code. That depends on your implementation.

    The point is, ARM TF(Trusted-Firmware) has already implemented many features and some of which are required.

    For example:

    * Secure/Non-secure world switching

    * PSCI interface

    * Interrupt initialization

    * EL3 runtime service

    The recommended scenario is:

    ARM TF (secure) -> UEFI/UBoot/Hypervisor (non-secure) -> OS (non-secure)

    And OS calls PSCI interface for power management events (on/off/suspend/...) through "SMC" which causes a synchronous exception to EL3 at which level ARM TF runtime service (BL3-1) is running. Only secure code can access power controller.

    If you don't care about secure/non-secure, and want to leave Linux to SEL1(secure-EL1). Then I think at least you need implement PSCI interface in your own firmware (whatever it's UBoot or bare-metal).

    As ARM Trusted-Firmware is a standard/rich-feature/open-source software stack, so I suggest to study/use it. It will give you better compatibility for any new feature of ARM.

Reply
  • 0 Arm Employee Badge in reply to Jorney

    Of course, any software could be secure code. That depends on your implementation.

    The point is, ARM TF(Trusted-Firmware) has already implemented many features and some of which are required.

    For example:

    * Secure/Non-secure world switching

    * PSCI interface

    * Interrupt initialization

    * EL3 runtime service

    The recommended scenario is:

    ARM TF (secure) -> UEFI/UBoot/Hypervisor (non-secure) -> OS (non-secure)

    And OS calls PSCI interface for power management events (on/off/suspend/...) through "SMC" which causes a synchronous exception to EL3 at which level ARM TF runtime service (BL3-1) is running. Only secure code can access power controller.

    If you don't care about secure/non-secure, and want to leave Linux to SEL1(secure-EL1). Then I think at least you need implement PSCI interface in your own firmware (whatever it's UBoot or bare-metal).

    As ARM Trusted-Firmware is a standard/rich-feature/open-source software stack, so I suggest to study/use it. It will give you better compatibility for any new feature of ARM.

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