On 1/13/25 1:15 PM, Biju Das wrote:
Hi Marex,
Thanks for the patch
-----Original Message-----
From: U-Boot <[email protected]> On Behalf Of Marek Vasut
Sent: 12 January 2025 22:37
Subject: [PATCH 2/3] image: Add support for starting TFA BL31 as fitImage
loadables
Add support for starting TFA from U-Boot running in EL3 as part of fitImage
boot, so the user can
start U-Boot in the highest privilege level on the platform, bundle TFA, Linux,
DT into a single
fitImage and boot such a bundle as a whole.
There are two main benefits of this approach. First is the ability to run
U-Boot in EL3, where it has
unrestricted access to the entire system and can act as a useful debug tool, as
it was always intended
to be used. Second is the ability to easily and safely update of any component
in the fitImage, be it
TFA, Linux or DT.
In this case, who will do switching from secure world to normal world, u-boot?
Do you have any link to the u-boot patch from secure to normal world switching
with kernel entry point passed to BL31?
Otherwise, kernel, also will be executing in secure world mode.
See 3/3 , U-Boot runs in EL3 , before starting kernel it jumps into TFA
BL31 , TFA BL31 does its setup and switches from EL3 to EL2 , TFA BL31
returns to U-Boot armv8_switch_to_el2 which checks if this code is
running in EL2 (it is) and does the last few steps before starting
kernel, and then finally jumps to the kernel .
