audk/ArmPlatformPkg/ArmVExpressPkg/Scripts/uefi-aarch64-bootstrap

AArch64 UEFI bootstraps

=======================



Copyright (c) 2011-2013 ARM Limited. All rights reserved.

See the `LICENSE.TXT` file for more information.



Contents:



* Introduction

* Build

* Use on ARMv8 RTSM and FVP models

* Use on ARMv8 Foundation model





Introduction

------------



A bootstrap can be used to change the model state, like the Exception

Level (EL), before executing the UEFI binary.



For the ARMv8 RTSM and FVP models this can be used to show/test the UEFI binary

starting at different exception levels. The ARMv8 models start at EL3 by

default.



In the case of the Foundation model a bootstrap is required to jump to the

UEFI binary as loaded in RAM. This is required as the Foundation model cannot

load and execute UEFI binaries directly. The Foundation model can only load and

execute ELF binaries.





Build

-----



Build the bootstraps using a AArch64 GCC cross-compiler. By default the

`Makefile` is configured to assume a GCC bare-metal toolchain:



    PATH=$PATH:<path/to/baremetal-tools/bin/> make clean

    PATH=$PATH:<path/to/baremetal-tools/bin/> make



To build the bootstraps with a Linux GCC toolchain use the following

commands:



    PATH=$PATH:<path/to/aarch64-linux-gnu-tools/bin/> make clean

    PATH=$PATH:<path/to/aarch64-linux-gnu-tools/bin/> CROSS_COMPILE=<gcc-prefix> make



The `gcc-prefix` depends on the specific toolchain distribution used. It can be

"aarch64-linux-gnu-" for example.



This will result in four `axf` files:



* uefi-bootstrap-el3 : The bootstrap jumps to the UEFI code in FLASH without

                     changing anything.



* uefi-bootstrap-el2 : Setup EL3 and switch the model to EL2 before jumping to the

                     UEFI code in FLASH.



* uefi-bootstrap-el1 : Setup EL3 and prepare to run at non-secure EL1. Switch to

                     non-secure EL1 and run the UEFI code in FLASH.



* uefi-bootstrap-el3-foundation : The bootstrap jumps to the UEFI code in RAM

                     without changing anything. Only to be used with the

                     Foundation model. The Foundation model does not have

                     non-secure memory at address `0x0` and thus the UEFI image

                     should be pre-loaded into non-secure RAM at address

                     `0xA0000000`.





Use on ARMv8 RTSM and FVP models

--------------------------------



Add the '-a' option to the model start script and point to the required

bootstrap:



    < ... model start script as described in top-level readme file ... >

     -a <path/to/bootstrap-binary-file>



NOTE: The Foundation model bootstrap should not be used with these models.





Use on ARMv8 Foundation model

-----------------------------



The Foundation model takes an option for an ELF file to be loaded as well as an

option to load a binary data blob into RAM. This can be used to run UEFI in the

following manner:



    <PATH_TO_INSTALLED_FOUNDATION_MODEL>/Foundation_v8 --cores=2 --visualization

      --image=uefi-bootstrap-el3-foundation.axf --nsdata=RTSM_VE_FOUNDATIONV8_EFI.fd@0xA0000000



NOTE: The RTSM version of the bootstraps and UEFI image will not work as

      expected on the Foundation model. Foundation model specific versions

      should be used.