ARM Trusted Firmware User Guide

Contents :

  1. Introduction

  2. Host machine requirements

  3. Tools

  4. Building the Trusted Firmware

  5. Obtaining the normal world software

  6. Running the software

  7. Introduction


This document describes how to build ARM Trusted Firmware and run it with a tested set of other software components using defined configurations on ARM Fixed Virtual Platform (FVP) models. It is possible to use other software components, configurations and platforms but that is outside the scope of this document.

This document should be used in conjunction with the Firmware Design.

  1. Host machine requirements

The minimum recommended machine specification for building the software and running the FVP models is a dual-core processor running at 2GHz with 12GB of RAM. For best performance, use a machine with a quad-core processor running at 2.6GHz with 16GB of RAM.

The software has been tested on Ubuntu 12.04.02 (64-bit). Packages used for building the software were installed from that distribution unless otherwise specified.

  1. Tools

The following tools are required to use the ARM Trusted Firmware:

  • git package to obtain source code

  • ia32-libs package

  • build-essential and uuid-dev packages for building UEFI and the Firmware Image Package(FIP) tool

  • bc and ncurses-dev packages for building Linux

  • Baremetal GNU GCC tools. Verified packages can be downloaded from [Linaro] Linaro Toolchain. The rest of this document assumes that the gcc-linaro-aarch64-none-elf-4.8-2013.11_linux.tar.xz tools are used.

    wget http://releases.linaro.org/13.11/components/toolchain/binaries/gcc-linaro-aarch64-none-elf-4.8-2013.11_linux.tar.xz
    tar -xf gcc-linaro-aarch64-none-elf-4.8-2013.11_linux.tar.xz
    
  • The Device Tree Compiler (DTC) included with Linux kernel 3.13 is used to build the Flattened Device Tree (FDT) source files (.dts files) provided with this software.

  • (Optional) For debugging, ARM Development Studio 5 (DS-5) v5.17.

  1. Building the Trusted Firmware

To build the software for the FVPs, follow these steps:

  1. Clone the ARM Trusted Firmware repository from GitHub:

    git clone https://github.com/ARM-software/arm-trusted-firmware.git
    
  2. Change to the trusted firmware directory:

    cd arm-trusted-firmware
    
  3. Set the compiler path, specify a Non-trusted Firmware image (BL3-3) and build:

    CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-none-elf- \
    BL33=<path-to>/<bl33_image>                               \
    make PLAT=fvp all fip
    

    By default this produces a release version of the build. To produce a debug version instead, refer to the "Debugging options" section below. UEFI can be used as the BL3-3 image, refer to the "Obtaining the normal world software" section below.

    The build process creates products in a build directory tree, building the objects and binaries for each boot loader stage in separate sub-directories. The following boot loader binary files are created from the corresponding ELF files:

    • build/<platform>/<build-type>/bl1.bin
    • build/<platform>/<build-type>/bl2.bin
    • build/<platform>/<build-type>/bl31.bin

    ... where <platform> currently defaults to fvp and <build-type> is either debug or release. A Firmare Image Package(FIP) will be created as part of the build. It contains all boot loader images except for bl1.bin.

    • build/<platform>/<build-type>/fip.bin

    For more information on FIPs, see the "Firmware Image Package" section in the Firmware Design.

  4. Copy the bl1.bin and fip.bin binary files to the directory from which the FVP will be launched. Symbolic links of the same names may be created instead.

  5. (Optional) Build products for a specific build variant can be removed using:

    make DEBUG=<D> PLAT=fvp clean
    

    ... where <D> is 0 or 1, as specified when building.

    The build tree can be removed completely using:

    make realclean
    

Creating a Firmware Image Package

FIPs are automatically created as part of the build instructions described in the previous section. It is also possible to independently build the FIP creation tool and FIPs if required. To do this, follow these steps:

Build the tool:

make -C tools/fip_create

It is recommended to remove the build artifacts before rebuilding:

make -C tools/fip_create clean

Create a Firmware package that contains existing FVP BL2 and BL3-1 images:

# fip_create --help to print usage information
# fip_create <fip_name> <images to add> [--dump to show result]
./tools/fip_create/fip_create fip.bin --dump \
   --bl2 build/fvp/debug/bl2.bin --bl31 build/fvp/debug/bl31.bin

 Firmware Image Package ToC:
---------------------------
- Trusted Boot Firmware BL2: offset=0x88, size=0x81E8
  file: 'build/fvp/debug/bl2.bin'
- EL3 Runtime Firmware BL3-1: offset=0x8270, size=0xC218
  file: 'build/fvp/debug/bl31.bin'
---------------------------
Creating "fip.bin"

View the contents of an existing Firmware package:

./tools/fip_create/fip_create fip.bin --dump

 Firmware Image Package ToC:
---------------------------
- Trusted Boot Firmware BL2: offset=0x88, size=0x81E8
- EL3 Runtime Firmware BL3-1: offset=0x8270, size=0xC218
---------------------------

Existing package entries can be individially updated:

# Change the BL2 from Debug to Release version
./tools/fip_create/fip_create fip.bin --dump \
  --bl2 build/fvp/release/bl2.bin

Firmware Image Package ToC:
---------------------------
- Trusted Boot Firmware BL2: offset=0x88, size=0x7240
  file: 'build/fvp/release/bl2.bin'
- EL3 Runtime Firmware BL3-1: offset=0x72C8, size=0xC218
---------------------------
Updating "fip.bin"

Debugging options

To compile a debug version and make the build more verbose use

CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-none-elf- \
BL33=<path-to>/<bl33_image>                               \
make PLAT=fvp DEBUG=1 V=1 all fip

AArch64 GCC uses DWARF version 4 debugging symbols by default. Some tools (for example DS-5) might not support this and may need an older version of DWARF symbols to be emitted by GCC. This can be achieved by using the -gdwarf-<version> flag, with the version being set to 2 or 3. Setting the version to 2 is recommended for DS-5 versions older than 5.16.

When debugging logic problems it might also be useful to disable all compiler optimizations by using -O0.

NOTE: Using -O0 could cause output images to be larger and base addresses might need to be recalculated (see the later memory layout section).

Extra debug options can be passed to the build system by setting CFLAGS:

CFLAGS='-O0 -gdwarf-2'                                    \
CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-none-elf- \
BL33=<path-to>/<bl33_image>                               \
make PLAT=fvp DEBUG=1 V=1 all fip

NOTE: The Foundation FVP does not provide a debugger interface.

Checking source code style

When making changes to the source for submission to the project, the source must be in compliance with the Linux style guide, and to assist with this check the project Makefile contains two targets, which both utilise the checkpatch.pl script that ships with the Linux source tree.

To check the entire source tree, you must first download a copy of checkpatch.pl (or the full Linux source), set the CHECKPATCH environment variable to point to the script and build the target checkcodebase:

make CHECKPATCH=../linux/scripts/checkpatch.pl checkcodebase

To just check the style on the files that differ between your local branch and the remote master, use:

make CHECKPATCH=../linux/scripts/checkpatch.pl checkpatch

If you wish to check your patch against something other than the remote master, set the BASE_COMMIT variable to your desired branch. By default, BASE_COMMIT is set to 'origin/master'.

  1. Obtaining the normal world software

Obtaining EDK2

Potentially any kind of non-trusted firmware may be used with the ARM Trusted Firmware but the software has only been tested with the EFI Development Kit 2 (EDK2) open source implementation of the UEFI specification.

Clone the EDK2 source code from GitHub. This version supports the Base and Foundation FVPs:

git clone -n https://github.com/tianocore/edk2.git
cd edk2
git checkout c1cdcab9526506673b882017845a043cead8bc69

To build the software to be compatible with Foundation and Base FVPs, follow these steps:

  1. Copy build config templates to local workspace

    # in edk2/
    . edksetup.sh
    
  2. Build the EDK2 host tools

    make -C BaseTools clean
    make -C BaseTools
    
  3. Build the EDK2 software

    CROSS_COMPILE=<absolute-path-to-aarch64-gcc>/bin/aarch64-none-elf- \
    make -f ArmPlatformPkg/Scripts/Makefile EDK2_ARCH=AARCH64          \
    EDK2_DSC=ArmPlatformPkg/ArmVExpressPkg/ArmVExpress-FVP-AArch64.dsc \
    EDK2_TOOLCHAIN=ARMGCC EDK2_MACROS="-n 6 -D ARM_FOUNDATION_FVP=1"
    

    The EDK2 binary for use with the ARM Trusted Firmware can then be found here:

    Build/ArmVExpress-FVP-AArch64/DEBUG_ARMGCC/FV/FVP_AARCH64_EFI.fd
    

    This will build EDK2 for the default settings as used by the FVPs. The EDK2 binary FVP_AARCH64_EFI.fd should be specified as BL33 in in the make command line when building the Trusted Firmware. See the "Building the Trusted Firmware" section above.

  4. (Optional) To boot Linux using a VirtioBlock file-system, the command line passed from EDK2 to the Linux kernel must be modified as described in the "Obtaining a root file-system" section below.

  5. (Optional) If legacy GICv2 locations are used, the EDK2 platform description must be updated. This is required as EDK2 does not support probing for the GIC location. To do this, first clean the EDK2 build directory.

    make -f ArmPlatformPkg/Scripts/Makefile EDK2_ARCH=AARCH64          \
    EDK2_DSC=ArmPlatformPkg/ArmVExpressPkg/ArmVExpress-FVP-AArch64.dsc \
    EDK2_TOOLCHAIN=ARMGCC clean
    

    Then rebuild EDK2 as described in step 3, using the following flag:

    -D ARM_FVP_LEGACY_GICV2_LOCATION=1
    

    Finally rebuild the Trusted Firmware to generate a new FIP using the instructions in the "Building the Trusted Firmware" section.

Obtaining a Linux kernel

The software has been verified using a Linux kernel based on version 3.13. Patches have been applied in order to enable the CPU idle feature.

Preparing a Linux kernel for use on the FVPs with CPU idle support can be done as follows (GICv2 support only):

  1. Clone Linux:

    git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
    

    Not all CPU idle features are included in the mainline kernel yet. To use these, add the patches from Sudeep Holla's kernel, based on Linux 3.13:

    cd linux
    git remote add -f --tags arm64_idle_genfw_ref git://linux-arm.org/linux-skn.git
    git checkout -b cpuidle arm64_idle_genfw_ref
    
  2. Build with the Linaro GCC tools.

    # in linux/
    make mrproper
    make ARCH=arm64 defconfig
    
    # Enable CPU idle
    make ARCH=arm64 menuconfig
    # CPU Power Management ---> CPU Idle ---> [*] CPU idle PM support
    # CPU Power Management ---> CPU Idle ---> ARM64 CPU Idle Drivers ---> [*] Generic ARM64 CPU idle Driver
    
    CROSS_COMPILE=<path-to-aarch64-gcc>/bin/aarch64-none-elf- \
    make -j6 ARCH=arm64
    
  3. Copy the Linux image arch/arm64/boot/Image to the working directory from where the FVP is launched. Alternatively a symbolic link may be used.

Obtaining the Flattened Device Trees

Depending on the FVP configuration and Linux configuration used, different FDT files are required. FDTs for the Foundation and Base FVPs can be found in the Trusted Firmware source directory under fdts/. The Foundation FVP has a subset of the Base FVP components. For example, the Foundation FVP lacks CLCD and MMC support, and has only one CPU cluster.

  • fvp-base-gicv2-psci.dtb

    (Default) For use with both AEMv8 and Cortex-A57-A53 Base FVPs with Base memory map configuration.

  • fvp-base-gicv2legacy-psci.dtb

    For use with AEMv8 Base FVP with legacy VE GIC memory map configuration.

  • fvp-base-gicv3-psci.dtb

    For use with both AEMv8 and Cortex-A57-A53 Base FVPs with Base memory map configuration and Linux GICv3 support.

  • fvp-foundation-gicv2-psci.dtb

    (Default) For use with Foundation FVP with Base memory map configuration.

  • fvp-foundation-gicv2legacy-psci.dtb

    For use with Foundation FVP with legacy VE GIC memory map configuration.

  • fvp-foundation-gicv3-psci.dtb

    For use with Foundation FVP with Base memory map configuration and Linux GICv3 support.

Copy the chosen FDT blob as fdt.dtb to the directory from which the FVP is launched. Alternatively a symbolic link may be used.

Obtaining a root file-system

To prepare a Linaro LAMP based Open Embedded file-system, the following instructions can be used as a guide. The file-system can be provided to Linux via VirtioBlock or as a RAM-disk. Both methods are described below.

Prepare VirtioBlock

To prepare a VirtioBlock file-system, do the following:

  1. Download and unpack the disk image.

    NOTE: The unpacked disk image grows to 2 GiB in size.

    wget http://releases.linaro.org/14.01/openembedded/aarch64/vexpress64-openembedded_lamp-armv8-gcc-4.8_20140126-596.img.gz
    gunzip vexpress64-openembedded_lamp-armv8-gcc-4.8_20140126-596.img.gz
    
  2. Make sure the Linux kernel has Virtio support enabled using make ARCH=arm64 menuconfig.

    Device Drivers  ---> Virtio drivers  ---> <*> Platform bus driver for memory mapped virtio devices
    Device Drivers  ---> [*] Block devices  --->  <*> Virtio block driver
    File systems    ---> <*> The Extended 4 (ext4) filesystem
    

    If some of these configurations are missing, enable them, save the kernel configuration, then rebuild the kernel image using the instructions provided in the section "Obtaining a Linux kernel".

  3. Change the Kernel command line to include root=/dev/vda2. This can either be done in the EDK2 boot menu or in the platform file. Editing the platform file and rebuilding EDK2 will make the change persist. To do this:

    1. In EDK2, edit the following file:

      ArmPlatformPkg/ArmVExpressPkg/ArmVExpress-FVP-AArch64.dsc
      
    2. Add root=/dev/vda2 to:

      gArmPlatformTokenSpaceGuid.PcdDefaultBootArgument|"<Other default options>"
      
    3. Remove the entry:

      gArmPlatformTokenSpaceGuid.PcdDefaultBootInitrdPath|""
      
    4. Rebuild EDK2 (see "Obtaining UEFI" section above).

  4. The file-system image file should be provided to the model environment by passing it the correct command line option. In the FVPs the following option should be provided in addition to the ones described in the "Running the software" section below.

    NOTE: A symbolic link to this file cannot be used with the FVP; the path to the real file must be provided.

    On the Base FVPs: -C bp.virtioblockdevice.image_path="/"

    On the Foundation FVP: --block-device="/"

  5. Ensure that the FVP doesn't output any error messages. If the following error message is displayed:

    ERROR: BlockDevice: Failed to open "<path-to>/<file-system-image>"!
    

    then make sure the path to the file-system image in the model parameter is correct and that read permission is correctly set on the file-system image file.

Prepare RAM-disk

To prepare a RAM-disk root file-system, do the following:

  1. Download the file-system image:

    wget http://releases.linaro.org/14.01/openembedded/aarch64/linaro-image-lamp-genericarmv8-20140127-635.rootfs.tar.gz
    
  2. Modify the Linaro image:

    # Prepare for use as RAM-disk. Normally use MMC, NFS or VirtioBlock.
    # Be careful, otherwise you could damage your host file-system.
    mkdir tmp; cd tmp
    sudo sh -c "zcat ../linaro-image-lamp-genericarmv8-20140127-635.rootfs.tar.gz | cpio -id"
    sudo ln -s sbin/init .
    sudo sh -c "echo 'devtmpfs /dev devtmpfs mode=0755,nosuid 0 0' >> etc/fstab"
    sudo sh -c "find . | cpio --quiet -H newc -o | gzip -3 -n > ../filesystem.cpio.gz"
    cd ..
    
  3. Copy the resultant filesystem.cpio.gz to the directory where the FVP is launched from. Alternatively a symbolic link may be used.

  4. Running the software


This version of the ARM Trusted Firmware has been tested on the following ARM FVPs (64-bit versions only).

  • Foundation_v8 (Version 2.0, Build 0.8.5206)
  • FVP_Base_AEMv8A-AEMv8A (Version 5.4, Build 0.8.5405)
  • FVP_Base_Cortex-A57x4-A53x4 (Version 5.4, Build 0.8.5405)
  • FVP_Base_Cortex-A57x1-A53x1 (Version 5.4, Build 0.8.5405)

NOTE: The software will not work on Version 1.0 of the Foundation FVP. The commands below would report an unhandled argument error in this case.

Please refer to the FVP documentation for a detailed description of the model parameter options. A brief description of the important ones that affect the ARM Trusted Firmware and normal world software behavior is provided below.

The Foundation FVP is a cut down version of the AArch64 Base FVP. It can be downloaded for free from ARM's website.

Running on the Foundation FVP

The following Foundation_v8 parameters should be used to boot Linux with 4 CPUs using the ARM Trusted Firmware.

NOTE: Using the --block-device parameter is not necessary if a Linux RAM-disk file-system is used (see the "Obtaining a File-system" section above).

NOTE: The --data="<path to FIP binary>"@0x8000000 parameter is used to load a Firmware Image Package at the start of NOR FLASH0 (see the "Building the Trusted Firmware" section above).

<path-to>/Foundation_v8                   \
--cores=4                                 \
--no-secure-memory                        \
--visualization                           \
--gicv3                                   \
--data="<path-to>/<bl1-binary>"@0x0       \
--data="<path-to>/<FIP-binary>"@0x8000000 \
--block-device="<path-to>/<file-system-image>"

The default use-case for the Foundation FVP is to enable the GICv3 device in the model but use the GICv2 FDT, in order for Linux to drive the GIC in GICv2 emulation mode.

The memory mapped addresses 0x0 and 0x8000000 correspond to the start of trusted ROM and NOR FLASH0 respectively.

Running on the AEMv8 Base FVP

The following FVP_Base_AEMv8A-AEMv8A parameters should be used to boot Linux with 8 CPUs using the ARM Trusted Firmware.

NOTE: Using cache_state_modelled=1 makes booting very slow. The software will still work (and run much faster) without this option but this will hide any cache maintenance defects in the software.

NOTE: Using the -C bp.virtioblockdevice.image_path parameter is not necessary if a Linux RAM-disk file-system is used (see the "Obtaining a root file-system" section above).

NOTE: The -C bp.flashloader0.fname parameter is used to load a Firmware Image Package at the start of NOR FLASH0 (see the "Building the Trusted Firmware" section above).

<path-to>/FVP_Base_AEMv8A-AEMv8A                       \
-C pctl.startup=0.0.0.0                                \
-C bp.secure_memory=0                                  \
-C cluster0.NUM_CORES=4                                \
-C cluster1.NUM_CORES=4                                \
-C cache_state_modelled=1                              \
-C bp.pl011_uart0.untimed_fifos=1                      \
-C bp.secureflashloader.fname="<path-to>/<bl1-binary>" \
-C bp.flashloader0.fname="<path-to>/<FIP-binary>"      \
-C bp.virtioblockdevice.image_path="<path-to>/<file-system-image>"

Running on the Cortex-A57-A53 Base FVP

The following FVP_Base_Cortex-A57x4-A53x4 model parameters should be used to boot Linux with 8 CPUs using the ARM Trusted Firmware.

NOTE: Using cache_state_modelled=1 makes booting very slow. The software will still work (and run much faster) without this option but this will hide any cache maintenance defects in the software.

NOTE: Using the -C bp.virtioblockdevice.image_path parameter is not necessary if a Linux RAM-disk file-system is used (see the "Obtaining a root file-system" section above).

NOTE: The -C bp.flashloader0.fname parameter is used to load a Firmware Image Package at the start of NOR FLASH0 (see the "Building the Trusted Firmware" section above).

<path-to>/FVP_Base_Cortex-A57x4-A53x4                  \
-C pctl.startup=0.0.0.0                                \
-C bp.secure_memory=0                                  \
-C cache_state_modelled=1                              \
-C bp.pl011_uart0.untimed_fifos=1                      \
-C bp.secureflashloader.fname="<path-to>/<bl1-binary>" \
-C bp.flashloader0.fname="<path-to>/<FIP-binary>"      \
-C bp.virtioblockdevice.image_path="<path-to>/<file-system-image>"

Configuring the GICv2 memory map

The Base FVP models support GICv2 with the default model parameters at the following addresses. The Foundation FVP also supports these addresses when configured for GICv3 in GICv2 emulation mode.

GICv2 Distributor Interface     0x2f000000
GICv2 CPU Interface             0x2c000000
GICv2 Virtual CPU Interface     0x2c010000
GICv2 Hypervisor Interface      0x2c02f000

The AEMv8 Base FVP can be configured to support GICv2 at addresses corresponding to the legacy (Versatile Express) memory map as follows. These are the default addresses when using the Foundation FVP in GICv2 mode.

GICv2 Distributor Interface     0x2c001000
GICv2 CPU Interface             0x2c002000
GICv2 Virtual CPU Interface     0x2c004000
GICv2 Hypervisor Interface      0x2c006000

The choice of memory map is reflected in the build variant field (bits[15:12]) in the SYS_ID register (Offset 0x0) in the Versatile Express System registers memory map (0x1c010000).

  • SYS_ID.Build[15:12]

    0x1 corresponds to the presence of the Base GIC memory map. This is the default value on the Base FVPs.

  • SYS_ID.Build[15:12]

    0x0 corresponds to the presence of the Legacy VE GIC memory map. This is the default value on the Foundation FVP.

This register can be configured as described in the following sections.

NOTE: If the legacy VE GIC memory map is used, then the corresponding FDT and BL3-3 images should be used.

Configuring AEMv8 Foundation FVP GIC for legacy VE memory map

The following parameters configure the Foundation FVP to use GICv2 with the legacy VE memory map:

<path-to>/Foundation_v8                   \
--cores=4                                 \
--no-secure-memory                        \
--visualization                           \
--no-gicv3                                \
--data="<path-to>/<bl1-binary>"@0x0       \
--data="<path-to>/<FIP-binary>"@0x8000000 \
--block-device="<path-to>/<file-system-image>"

Explicit configuration of the SYS_ID register is not required.

Configuring AEMv8 Base FVP GIC for legacy VE memory map

The following parameters configure the AEMv8 Base FVP to use GICv2 with the legacy VE memory map. They must added to the parameters described in the "Running on the AEMv8 Base FVP" section above:

-C cluster0.gic.GICD-offset=0x1000                  \
-C cluster0.gic.GICC-offset=0x2000                  \
-C cluster0.gic.GICH-offset=0x4000                  \
-C cluster0.gic.GICH-other-CPU-offset=0x5000        \
-C cluster0.gic.GICV-offset=0x6000                  \
-C cluster0.gic.PERIPH-size=0x8000                  \
-C cluster1.gic.GICD-offset=0x1000                  \
-C cluster1.gic.GICC-offset=0x2000                  \
-C cluster1.gic.GICH-offset=0x4000                  \
-C cluster1.gic.GICH-other-CPU-offset=0x5000        \
-C cluster1.gic.GICV-offset=0x6000                  \
-C cluster1.gic.PERIPH-size=0x8000                  \
-C gic_distributor.GICD-alias=0x2c001000            \
-C bp.variant=0x0

The bp.variant parameter corresponds to the build variant field of the SYS_ID register. Setting this to 0x0 allows the ARM Trusted Firmware to detect the legacy VE memory map while configuring the GIC.


Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.