How to Use GDB for ARM Debugging: Step-by-Step Guide
To debug ARM programs with
gdb, use arm-none-eabi-gdb or a similar ARM-targeted GDB version. Connect to your ARM device or emulator, load your program, set breakpoints, and use commands like run, step, and continue to control execution and inspect state.Syntax
The basic syntax to start ARM debugging with GDB is:
arm-none-eabi-gdb [executable]: Launches GDB for ARM with your program.target remote [ip]:[port]: Connects to a remote ARM device or emulator via TCP.load: Loads the program onto the target device.break [location]: Sets a breakpoint at a function or line.run: Starts program execution.step: Executes the next instruction or source line.continue: Resumes execution until next breakpoint.print [variable]: Displays the value of a variable.
This syntax lets you control and inspect ARM programs during debugging.
bash
arm-none-eabi-gdb myprogram.elf (gdb) target remote 192.168.0.10:3333 (gdb) load (gdb) break main (gdb) run (gdb) step (gdb) print var (gdb) continue
Example
This example shows how to debug a simple ARM program using arm-none-eabi-gdb connected to a QEMU ARM emulator.
bash
arm-none-eabi-gdb hello_world.elf (gdb) target remote :1234 (gdb) load (gdb) break main (gdb) run (gdb) step (gdb) print counter (gdb) continue
Output
(gdb) target remote :1234
Remote debugging using :1234
0x00010400 in main ()
(gdb) load
Loading section .text, size 0x100 lma 0x10000
Start address 0x10000, load size 256.
(gdb) break main
Breakpoint 1 at 0x10400: file main.c, line 10.
(gdb) run
Starting program: /path/hello_world.elf
Breakpoint 1, main () at main.c:10
10 int counter = 0;
(gdb) step
11 counter++;
(gdb) print counter
$1 = 0
(gdb) continue
Continuing.
[Inferior 1 (process 1234) exited normally]
Common Pitfalls
Common mistakes when using GDB for ARM debugging include:
- Using the wrong GDB version not built for ARM targets.
- Not connecting to the remote target before loading or running the program.
- Forgetting to load the program onto the device before starting execution.
- Setting breakpoints before the program is loaded, which may cause errors.
- Confusing source-level debugging with instruction-level debugging; ARM debugging often requires attention to assembly instructions.
Always ensure your GDB matches your ARM architecture and that your debugging session follows the correct connection and loading order.
gdb
;; Wrong order example (gdb) load Error: No target connected. ;; Correct order example (gdb) target remote 192.168.0.10:3333 (gdb) load
Quick Reference
| Command | Description |
|---|---|
| arm-none-eabi-gdb [file] | Start GDB for ARM with your program |
| target remote [ip]:[port] | Connect to remote ARM device or emulator |
| load | Load program onto the target |
| break [location] | Set breakpoint at function or line |
| run | Start program execution |
| step | Execute next instruction or line |
| continue | Resume execution until next breakpoint |
| print [variable] | Display variable value |
| info registers | Show CPU registers state |
| disassemble | Show assembly code around current PC |
Key Takeaways
Use an ARM-specific GDB like arm-none-eabi-gdb for proper debugging support.
Always connect to your ARM target before loading and running the program.
Set breakpoints after loading the program to avoid errors.
Use commands like step, continue, and print to control and inspect execution.
Check registers and disassemble instructions for low-level ARM debugging.