Using gdbserver

gdbserver is the remotization of ptrace(2)
You run gdbserver on the target like you'd invoke gdb
You control gdbserver through a serial or TCP port
On the host, a specific target-aware gdb is used
It must read and understand information in the target ELF
It must be able to disassemble for the target architecture
The cross-gdb (e.g.: arm-linux-gdb) si called just like gdb
It uses a binary file with all symbolic information
It accepts the "target remote" command to export ptrace actions

$ gdbserver host:2000  myapp
$ arm-linux-gdb  vmlinux
    target remote peedi:2000
    set print elements 16384
    set height 30
    p log_buf
    bt