A couple of months ago I posted this blog discussing how to get started with the Fixed Virtual Platform supplied with DS-5 Ultimate Edition. I'm writing this blog as a follow up, as ARM has just released their first ARMv8 Development Platform, Juno. Furthermore, in DS-5 version 5.19 (and later) there is a ready made debug configuration for the Juno Platform. You can download the latest version of DS-5 here. For more on Juno, see other blogs from my colleagues here and here. Linux and Android ports to this board are available via Linaro.I used the 14.06 Linaro LAMP file system in the examples below, which was the latest available at the time of writing.
One of the best things about using DS-5 is that the look and feel is very consistent, regardless of the type of target you are using. The only notable difference between using DS-5 with the Juno (or any other) platform vs the Fast Model, is in the Debug Configuration Pane.
Let's start with configuring a JTAG based debug connection using DSTREAM. Connect the DSTREAM hardware to the JTAG port at the rear of the Juno platform. Note that if TPIU ("off-chip") trace is needed, you will need to remove the top of the casing to access the trace connectors.
Launch the Eclipse GUI, and select Run → Debug Configurations to launch the pane. On the left hand side, select DS-5 Debugger, and click on the New Configuration Button. Give the configuration a meaningful name. You will see a long list of known targets, in what we call the configuration database. Typing "Juno" in the filter window will jump straight to the required configuration database entry, which you can expand like this:
You will notice a wide variety of options here. You will see options to connect to the individual CPUs present in the platform. You also have options to connect to the distinct Cortex-A53 and Cortex-A57 CPU clusters (in an SMP configuration). Finally you have an option to connect to all six application processors in a big.LITTLE configuration. You will need to understand how the platform boots to know which is available and when. Assuming you are using the platform exactly as supplied by ARM, the initial bootloader and UEFI run on Cortex-A53_0 (as labelled above). The Cortex-A57 cluster is held in reset, during this process, and so any attempt to connect to any of the Cortex-A57 processors, including the big.LITTLE configuration, will result in a debugger error. You should select either the Cortex-A53_0 or the Cortex-A53x4 SMP connections. If you are connecting to a fully booted system, you should be able to select any of the options. Note if running Linux, and debug symbols of your kernel are available, you may wish to use the connections listed under "Linux Kernel and/or Device Driver Debug" for enhanced debugger features.
Click the DTSL Options "Edit" button to show the range of different trace configurations available to you. You can enable trace for any or all CPUs that you wish to connect to.
Click the Browse button to locate your DSTREAM unit. Finally, use the File and Debugger tabs to configure your debug session as necessary. Click Apply to save your setup and then OK, to commence the debug session.
Example 1: Debugging the Cortex-M3
Example 2: Debugging the Cortex-A53 cluster (UEFI running on target)
Example 3: Debugging the entire big.LITTLE cluster (Linux running on target)
For Linux Application Debug, the steps are identical to those in my previous blog. I did however spot a problem with the Linux Application Debug option within the Juno configuration database entry, which refers to a AArch32 gdbserver (code on Juno is highly likely to be running in AArch64).
If you attempt to use this configuration (with AArch64 code) you get an unrecoverable error of the form:
! Failed to read state of device gdbserver
! The address "<address>" is invalid
The solution to this is to use the Linux Application Debug → Application Debug → Connections via AArch64 gdbserver configuration:
DS-5 Ultimate Edition has full Streamline support for Cortex-A53 and Cortex-A57, Mali-T624, and other system hardware present on Juno. Initial support is provided within the Linaro images, and I expect this to be extended over time.
Both DS-5 Ultimate Edition v5.19 and the Juno ARM Development Platform are available to order now. Please contact your ARM Representative for more information.