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EL3 execution

Hello Experts,

I need to operate a custom app at EL3 on a Cortex-A53 core running on the i.MX8 based platform. The bootflow shows me that a hand-off from ATF (BL31) to U-boot (BL33) is where the transition from EL3 to EL2 occurs for Uboot and it stays at EL2.

Can anyone suggest a procedure or mechanism to keep the Uboot and custom apps running at EL3? Are there any examples ?

Thanks in advance.

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0 segfault over 2 years ago in reply to Martin Weidmann

Thanks for the reply. The EL3 requirement is imposed by the BSP vendor supplying the RTOS. At this time the purpose is not clear. Currently, I can see U-boot operating after BL31 handoff at EL2.

Can you suggest what can be customized in BL31 (ATF) for initial experiments?

I tried some mods to BL31 code to avoid the EL2 setup but that appears to fail.
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0 segfault over 2 years ago in reply to Martin Weidmann

Thanks for the reply. The EL3 requirement is imposed by the BSP vendor supplying the RTOS. At this time the purpose is not clear. Currently, I can see U-boot operating after BL31 handoff at EL2.

Can you suggest what can be customized in BL31 (ATF) for initial experiments?

I tried some mods to BL31 code to avoid the EL2 setup but that appears to fail.
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0 vstehle over 2 years ago in reply to segfault

Hi,

There seem to be a way in TF-A to boot an el3 payload instead of BL31.

Best regards,

Vincent.
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