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Debugging with openocd

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Naoki Aizu edited this page May 13, 2013 · 4 revisions

JTAG hardware

Flyswatter2

Installing OpenOCD

  • Installing Packages
$ sudo apt-get install libusb-1.0-0 libusb-dev libftdi1 libftdi-dev tcl libtool automake texinfo
  • Downloading OpenOCD
$ git clone git://git.code.sf.net/p/openocd/code openocd

note: tested version is v0.7.0

  • Compiling OpenOCD
$ cd openocd
$ git checkout -b v0.7.0 v0.7.0
$ ./bootstrap
$ ./configure --enable-maintainer-mode --enable-ft2232_libftdi
$ make
$ sudo make install
  • Copy freertos-multicore/FreeRTOS/Demo/CORTEX_M3_PANDA/misc/omap4460.cfg to /usr/local/share/openocd/scripts/target/

Running OpenOCD

Connecting the Flyswatter2 and the Pandaboard ES

See "Flyswatter2 Pandaboard How To"

Boot OpenOCD

$ sudo /usr/local/bin/openocd -s /usr/local/share/openocd/scripts/ -f interface/flyswatter2.cfg -f board/ti_pandaboard_es.cfg

Debugging Linux Kernel(Cortex-A9 Side)

  • Running GDB
$ arm-none-linux-gnueabi-gdb vmlinux
  • Connecting OpenOCD
(gdb) target remote localhost:3333
  • Start target
(gdb) c
  • Example
(gdb) target remote localhost:3333
Remote debugging using localhost:3333
0x00035f4a in ?? ()
(gdb) b start_kernel               // set breakpoint on function that running on cpu core 0
Breakpoint 1 at 0xc069b6b0: file init/main.c, line 475.
(gdb) b secondary_start_kernel     // set breakpoint on function that running on cpu core 1
Breakpoint 2 at 0xc04ec834: file arch/arm/kernel/smp.c, line 261.
(gdb) c
Continuing.

Breakpoint 1, start_kernel () at init/main.c:475
475             smp_setup_processor_id();
(gdb) monitor cortex_a smp_gdb    // check current cpu core number
gdb coreid  0 -> -1               // current cpu core number is 0
(gdb) c
Continuing.

Breakpoint 2, secondary_start_kernel () at arch/arm/kernel/smp.c:261
261             atomic_inc(&mm->mm_count);
(gdb) monitor cortex_a smp_gdb    // check current cpu core number
gdb coreid  1 -> -1               // current cpu core number is 1
(gdb)

Debugging Linux Kernel module

  • Running GDB and start target
$ arm-none-linux-gnueabi-gdb vmlinux
(gdb) target remote localhost:3333
Remote debugging using localhost:3333
0x00035f4a in ?? ()
(gdb) c
  • Find the base address of kernel module on target
# cat /proc/modules
rpmsg_client_sample2 1850 0 - Live 0xbf023000 (O)
(the rest omitted)
  • Halt target(Press Ctrl+C on GDB terminal)
Continuing.
^C
Program received signal SIGINT, Interrupt.
  • Load symbol to GDB
(gdb) add-symbol-file rpmsg_client_sample2.ko 0xbf023000 -readnow
add symbol table from file "rpmsg_client_sample2.ko" at
        .text_addr = 0xbf023000
(y or n) y
Reading symbols from /home/n-aizu/work/pandaes/rpmsg/rpmsg_client_sample2.ko...expanding to full symbols...done.
  • Set breakpoint on kernel module code
(gdb) tb rpmsg_sample2_cb
Temporary breakpoint 1 at 0xbf023000
(gdb) c
Continuing.

Temporary breakpoint 1, rpmsg_sample2_cb (rpdev=0xebaf0a00, data=0xd9044810, len=4, priv=0x0, src=3955130188)

Debugging FreeRTOS(Cortex-M3 Side)

  • Connecting OpenOCD with telnet
$ telnet localhost 4444
  • Switch to Cortex-M3 core 0
> targets omap4460.m30
  • Switch to Cortex-M3 core 1
> targets omap4460.m31

Warning
FreeRTOS Multicore check timeout on cpu core 0.
So if Cortex-M3 core 0 is halted, timeout event is never occured on Cortex-M3 core 1.
(vTaskDelay/vTaskDelayUntill are not working and queue APIs are never timeouted.)

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