Arm Development Studio Platinum 2021.a is required to debug RD_N2 FVP. 

Download Software Stack

Select a Reference Design (RD) platform. There is a list of platforms here. For this guide we are using RD-N2 release tag RD-INFRA-2021.05.27.

For this guide, we have installed the software stack to ~/rd-infra.

Download the software stack using the guide here.

Setup Software Stack for Debugging

Make sure model-scripts/sgi/uefi.sh contains platforms_rdinfra[rdn2]=1

~/rd-infra$ grep "platforms_rdinfra\[rdn2\]" model-scripts/sgi/uefi.sh
platforms_rdinfra[rdn2]=1

Modify PlatformDxe.inf

In uefi/edk2/edk2-platforms/Platform/ARM/SgiPkg/Drivers/PlatformDxe/PlatformDxe.inf under section Protocols add gHestTableProtocolGuid.

[Protocols] 
  gEfiAcpiTableProtocolGuid          ## CONSUMES 
  gEfiAcpiSdtProtocolGuid            ## CONSUMES 
  gHestTableProtocolGuid             ## SOMETIMES CONSUMES 

Build UEFI edk2 

Now build the software stack. This generates the config files we need to modify. 

~/rd-infra$ ./build-scripts/build-test-uefi.sh -p rdn2 all

Modify tools_def 

In uefi/edk2/Conf/tools_def.txt and uefi/edk2/BaseTool/Conf/tools_def.template remove -Os from line DEFINE GCC_ALL_CC_FLAGS. This makes debugging much easier by not space optimising the firmware. 

uefi/edk2/Conf/tools_def.txt: 

DEFINE GCC_ALL_CC_FLAGS         = -g -fshort-wchar -fno-builtin -fno-strict-aliasing -Wall -Werror -Wno-array-bounds -include AutoGen.h -fno-common

Add –g to DEFINE_GCC_ASM_FLAGS to generate debug information. 

DEFINE GCC_ASM_FLAGS              = -g -c -x assembler -imacros AutoGen.h

Optional: Update tools_def.template to reflect these changes in the future. 

~/rd-infra$ cp uefi/edk2/Conf/tools_def.txt uefi/edk2/BaseTools/Conf/tools_def.template

Disable SPM. The build will fail unless it’s disabled. 

In build-scripts/configs/rdn2/rdn2 make ARM_TF_ENABLE_SPM=0

Set DebugPrintErrorLevel 

In uefi/edk2/edk2-platforms/Platform/ARM/SgiPkg/RdN2/RdN2.dsc add the following line in section PcdsFixedAtBuild.common to enable verbose printing. 

gEfiMdePkgTokenSpaceGuid.PcdDebugPrintErrorLevel|0x00400000

Set 0x00400000 to a combination of these flags: 

#define DEBUG_INIT      0x00000001  // Initialization
#define DEBUG_WARN      0x00000002  // Warnings
#define DEBUG_LOAD      0x00000004  // Load events
#define DEBUG_FS        0x00000008  // EFI File system
#define DEBUG_POOL      0x00000010  // Alloc & Free (pool)
#define DEBUG_PAGE      0x00000020  // Alloc & Free (page)
#define DEBUG_INFO      0x00000040  // Informational debug messages
#define DEBUG_DISPATCH  0x00000080  // PEI/DXE/SMM Dispatchers
#define DEBUG_VARIABLE  0x00000100  // Variable
#define DEBUG_BM        0x00000400  // Boot Manager
#define DEBUG_BLKIO     0x00001000  // BlkIo Driver
#define DEBUG_NET       0x00004000  // Network Io Driver
#define DEBUG_UNDI      0x00010000  // UNDI Driver
#define DEBUG_LOADFILE  0x00020000  // LoadFile
#define DEBUG_EVENT     0x00080000  // Event messages
#define DEBUG_GCD       0x00100000  // Global Coherency Database changes
#define DEBUG_CACHE     0x00200000  // Memory range cachability changes
#define DEBUG_VERBOSE   0x00400000  // Detailed debug messages that may
                                    // significantly impact boot performance
#define DEBUG_ERROR     0x80000000  // Error

from uefi/edk2/MdePkg/Include/Library/DebugLib.h 

Install FVP 

Download the correct FVP version for the platform and version you selected. 

For RD-N2 version RD-INFRA-2021.05.27 navigate to Neoverse N2 Reference Design FVP and click Download RD-N2. 

Run the installer FVP_RD_N2.sh. 

Modify FVP start script 

Modify model-scripts/rdinfra/platforms/rdn2/run_model.sh: 

remove -R parameter from PARAMS= section. This stops the model from running as soon as a debug server is connected. 

PARAMS="--data css.scp.armcortexm7ct=$OUTDIR/scp_ramfw.bin@0x0BD80000 \
	--data css.mcp.armcortexm7ct=$OUTDIR/mcp_ramfw.bin@0x0BF80000 \
	-C css.mcp.ROMloader.fname=$OUTDIR/mcp_romfw.bin \
	-C css.scp.ROMloader.fname=$OUTDIR/scp_romfw.bin \
	-C css.trustedBootROMloader.fname=$OUTDIR/$BL1_IMAGE \
	-C board.flashloader0.fname=$OUTDIR/$FIP_IMAGE \
	-C board.flashloader1.fname=$PWD/nor1_flash.img \
	-C board.flashloader1.fnameWrite=$PWD/nor1_flash.img \
	-C board.flashloader2.fname=$PWD/nor2_flash.img \
	-C board.flashloader2.fnameWrite=$PWD/nor2_flash.img \
	-S \
	-C css.scp.pl011_uart_scp.out_file=${MODEL_TYPE,,}/${UART0_SCP_OUTPUT_FILE_NAME} \
	-C css.scp.pl011_uart_scp.unbuffered_output=1 \
	-C css.scp.pl011_uart_scp.uart_enable=true \

Rebuild: 

~/rd-infra$ ./build-scripts/build-test-uefi.sh -p rdn2 all

Debug RDN2 

Find the start address of UEFI module 

TF-A loads BL33_AP_UEFI binary (the UEFI firmware) to the address specified by PLAT_ARM_NS_IMAGE_BASE in arm-tf/include/plat/arm/css/common/css_dev.h 

~/rd-infra$ grep PLAT_ARM_NS_IMAGE_BASE arm-tf/include/plat/arm/css/common/css_def.h

#define PLAT_ARM_NS_IMAGE_BASE U(0xE0000000)

The start address is 0xE0000000 

Start FVP 

Update MODEL environment variable with your FVP_RD_N2 model executable. 

export MODEL=~/FVP_RD_N2/models/Linux64_GCC-6.4/FVP_RD_N2

Go to model-scripts/rdinfra and run uefi.sh -p rdn2 

~/rd-infra$ cd model-scripts/rdinfra/ 

~/rd-infra/model-scripts/rdinfra$ ./uefi.sh -p rdn2 

The FVP will now start and wait for a debugger to connect. 

Create a debug connection 

Launch ArmDS Platinum 2021.a 

Create a new debug connection 

Select "Model Connection" and next

Enter a name for the connection.

Select "Add a new Model"

Select CADI as the model interface

Select "Browse for model running on local host"

Once your model terminal says “CADI Debug Server started for ARM Models...” the model should appear in arm DS.

Click Finish. The edit configuration window should then appear. 

Under “Connection” select Imported/Infra5_RD_N2/Bare Metal Debug/ARM_Neoverse-N2x15 Multi-Cluster SMP

Under Debugger, check “Execute Debugger Commands” and enter a breakpoint for the UEFI entry point we found earlier. 

Click Debug. The debugger should connect to the FVP. 

Currently it has stopped at EL3:0x00000000. This is the TF-A firmware. Click continue (F8)  to start execution. It will then break at EL2N:0xE0000000.