8.2.6. Connections to a target OS using NFS (GDB-NFS)

This is useful for developing software on deeply embedded systems, and also for debugging brand new targets where only the CPU and RAM are initially known to work. Connections of this type are referred to as GDB-NFS connections. The GDB-NFS connection method is shown in Figure 8.5.

Figure 8.5. GDB-NFS connections


For example, the minimum I/O support that Linux requires is a system console and a root file system. You can connect the console to a GDB command-line console and, with the appropriate driver, you can mount the root file system over NFS with RealView ICE acting as a bridge. Alternatively, you might have a file system and kernel loaded into memory and booted, and an NFS file system mounted to be shared later (see Loading and booting a complete system).

Note

This network connection is not as fast as an office LAN, because of the limited bandwidth of DCC.

Procedure for debugging a target using a GDB-NFS connection

If your target has a complete operating system, you can mount a file system over NFS. In this case, RealView ICE acts as a bridge.

To debug a target using a GDB-NFS connection:

  1. Power up your target hardware and RealView ICE unit.

  2. Load the Linux kernel and uBoot image using rviload. For example:

    RVIv14 Utils> ./rviload --host=rvi5 -j1000000 -mVEC -a0 7fc0:uImage 1000000:u-boot.bin
    

    Press Return. Messages appear showing u-boot loading and running the Linux kernel.

    Note

    This is similar for rviload.exe for MSDOS users.

  3. Mount the directory exported by NFS using the following command:

    ~ # mount -t nfs -n client_IP_address:/exported_directory /mnt
    
Copyright © 2002, 2004-2008 ARM Limited. All rights reserved.ARM DUI 0155J
Non-Confidential