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ARM-software / tf-issues

Issue tracking for the ARM Trusted Firmware project
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execution level transition in arm trusted firmware #7

Closed chinamao closed 10 years ago

chinamao commented 10 years ago

hi, experts: After review trusted firmware code, i found the execution level change flow is:

  1. BL1 ---- EL3 and in secure state
  2. BL2 ---- EL1 and in seucre state
  3. BL31---- EL3 and in secure state
  4. before jump to UEFI bootloader, BL31 will chane to EL2 and in non-secure state

Is my understand right?

achingupta commented 10 years ago

Almost except for the fact that BL31 will jump to the next highest non-secure exception level available which might be EL2 or NS-EL1.

hth!

chinamao commented 10 years ago

got it! thank you!