Book Image

Mastering Embedded Linux Programming

By : Chris Simmonds
Book Image

Mastering Embedded Linux Programming

By: Chris Simmonds

Overview of this book

Mastering Embedded Linux Programming takes you through the product cycle and gives you an in-depth description of the components and options that are available at each stage. You will begin by learning about toolchains, bootloaders, the Linux kernel, and how to configure a root filesystem to create a basic working device. You will then learn how to use the two most commonly used build systems, Buildroot and Yocto, to speed up and simplify the development process. Building on this solid base, the next section considers how to make best use of raw NAND/NOR flash memory and managed flash eMMC chips, including mechanisms for increasing the lifetime of the devices and to perform reliable in-field updates. Next, you need to consider what techniques are best suited to writing applications for your device. We will then see how functions are split between processes and the usage of POSIX threads, which have a big impact on the responsiveness and performance of the final device The closing sections look at the techniques available to developers for profiling and tracing applications and kernel code using perf and ftrace.
Table of Contents (22 chapters)
Mastering Embedded Linux Programming
About the Author
About the Reviewers

Starting to debug

Now that you have gdbserver installed on the target and a cross GDB on the host you can start a debug session.

Connecting GDB and gdbserver

The connection between GDB and gdbserver can be through a network or a serial interface. In the case of a network connection, you launch gdbserver with the TCP port number to listen on and, optionally, an IP address to accept connections from. In most cases you don't care which IP address is going to connect, so you can just give the port number. In this example gdbserver waits for a connection on port 10000 from any host:

# gdbserver :10000 ./hello-world
Process hello-world created; pid = 103
Listening on port 10000

Next, start the copy of GDB from your toolchain, giving the same program as an argument so that GDB can load the symbol table:

$ arm-poky-linux-gnueabi-gdb hello-world

In GDB, you use the command target remote to make the connection, giving the IP address or host name of the target and the port it is waiting on:

(gdb) target...