Gdb
gdb GNU Debugger
^ To Use openocd With Zephyr Projects
2021-09-17 Debugging Zephyr applications:
Openocd reference:
- https://openocd.org/doc/html/GDB-and-OpenOCD.html
- https://openocd.org/doc/pdf/openocd.pdf 2020-09-13 dated version of `openocd` manual
- https://openocd.org/doc/html/GDB-and-OpenOCD.html URL repeated here, see line:
-
However for some, eg. FreeRTOS, uC/OS-III and Zephyr, extra steps must be taken.
Zephyr must be compiled with the DEBUG_THREAD_INFO option. This will generate some symbols with information needed in order to build the list of threads.
Zephyr project and DEBUG_THREAD_INFO symbol use, location in Kconfig files:
^ First Page Entry or Section
How to have gdb stop on access to a memory location within a range of memory addresses, popular solution mentions use of valgrind
:
An excerpt from above StackOverflow page to highlight the issue:
11 I am debugging a program in gdb and I want the program to stop when the memory region 0x08049000 to 0x0804a000 is accessed. When I try to set memory breakpoints manually, gdb does not seem to support more than two locations at a time. (gdb) awatch *0x08049000 Hardware access (read/write) watchpoint 1: *0x08049000 (gdb) awatch *0x08049001 Hardware access (read/write) watchpoint 2: *0x08049001 (gdb) awatch *0x08049002 Hardware access (read/write) watchpoint 3: *0x08049002 (gdb) run Starting program: /home/iblue/git/some-code/some-executable Warning: Could not insert hardware watchpoint 3. Could not insert hardware breakpoints: You may have requested too many hardware breakpoints/watchpoints. There is already a question where this has been asked and the answer was, that it may be possible to do this with valgrind. Unfortunately the answer does not contain any examples or reference to the valgrind manual, so it was not very enlightning: How can gdb be used to watch for any changes in an entire region of memory? So: How can I watch the whole memory region? c linux debugging gdb Share Improve this question Follow edited May 23 '17 at 12:32 Community♦ 111 silver badge asked Jun 12 '12 at 20:30 iblue 26.9k1818 gold badges8282 silver badges125125 bronze badges Interesting fact: PowerPC has ranged breakpoints (but not watchpoints ?): stackoverflow.com/questions/13410941/… – Ciro Santilli 新疆再教育营六四事件法轮功郝海东 Jul 27 '15 at 16:09 x86 supports small watch ranges up to 8 bytes: en.wikipedia.org/wiki/X86_debug_register – Ciro Santilli 新疆再教育营六四事件法轮功郝海东 Aug 12 '15 at 12:09 Add a comment 2 Answers 29 If you use GDB 7.4 together with Valgrind 3.7.0, then you have unlimited "emulated" hardware watchpoints. Start your program under Valgrind, giving the arguments --vgdb=full --vgdb-error=0 then use GDB to connect to it (target remote | vgdb). Then you can e.g. watch or awatch or rwatch a memory range by doing rwatch (char[100]) *0x5180040 See the Valgrind user manual on gdb integration for more details Share Improve this answer Follow edited Jun 17 '12 at 17:57 iblue 26.9k1818 gold badges8282 silver badges125125 bronze badges answered Jun 13 '12 at 20:00 phd 52133 silver badges33 bronze badges 4 After I spent the better part of the day fiddling with mprotect and abusing SIGSEV handlers to break on memory access, I tried this. It works perfectly. You saved my day. Thank you! – iblue Jun 13 '12 at 23:00 Yes, +1 also. I've been hunting for a feature like this for months. – Crashworks Jun 14 '12 at 0:10 So, how does one determine the heap address for the process started by valgrind? I usually do this via /proc/[pid]/maps but when I start python via this valgrind command, the maps file doesn't have an entry identified by [heap] as I'm used to finding. – Andrew Falanga Feb 11 '16 at 19:59 I realise that this answer was written a long time ago, but I am confused by this answer, because gdb can do that by itself, without valgrind's help. At least it can now. It will resort to single-step and check repeatedly. That's obviously really expensive (like valgrind is), so you would narrow it down to when the corruption is about to happen soon, then create the watchpoint, so you don't have it running slow the whole debug run. – doug65536 Dec 10 '20 at 3:40
^ openocd Adapter Definitions Files
Mentioned in [ openocd documentation entry point] this debugging utility typically requires two key configuration files, one config file to describe the often physical, hardware based programming and debugging adapter, and a config file to describe the targeted board or SoC where firmware that is running will be debugged.
Temporary learning note here, local instances of openocd's "ships with" adapter files:
/home/ted/projects/openocd-code/tcl/interface/ftdi/ /home/ted/zephyr-sdk-0.12.4/sysroots/x86_64-pokysdk-linux/usr/share/openocd/scripts/interface/ftdi/ /opt/zephyr-sdk-0.12.4/sysroots/x86_64-pokysdk-linux/usr/share/openocd/scripts/interface/ftdi /usr/local/share/openocd/scripts/interface/ftdi
Ugh, which one of these is referenced when calling `west debug` on a given local Zephyr project? . . . want to answer this - TMH
Invoking `west -v debug` gives:
ted@localhost:~/projects/zephyr-based/z9/aws-iot-stand-alone$ west -v debug ZEPHYR_BASE=/home/ted/projects/zephyr-based/z9/zephyr (origin: configfile) -- west debug: rebuilding cmake version 3.21.1 is OK; minimum version is 3.13.1 Running CMake: /usr/bin/cmake --build /home/ted/projects/zephyr-based/z9/aws-iot-stand-alone/build [0/17] Performing build step for 'spm_subimage' ninja: no work to do. [1/5] Performing build step for 'mcuboot_subimage' ninja: no work to do. -- west debug: using runner jlink runners.jlink: JLINKARM_GetDLLVersion()=75001 -- runners.jlink: JLink version: 7.50a -- runners.jlink: J-Link GDB server running on port 2331; thread info enabled runners.jlink: JLinkGDBServer -select usb -port 2331 -if swd -speed 4000 -device cortex-m33 -silent -singlerun -nogui -rtos /opt/SEGGER/JLink_V750a/GDBServer/RTOSPlugin_Zephyr runners.jlink: /opt/zephyr-sdk-0.12.4/arm-zephyr-eabi/bin/arm-zephyr-eabi-gdb /home/ted/projects/zephyr-based/z9/aws-iot-stand-alone/build/zephyr/zephyr.elf -ex 'target remote :2331' -ex 'monitor halt' -ex 'monitor reset' -ex load SEGGER J-Link GDB Server V7.50a Command Line Version JLinkARM.dll V7.50a (DLL compiled Jul 8 2021 18:20:53) -----GDB Server start settings----- GDBInit file: none GDB Server Listening port: 2331 SWO raw output listening port: 2332 Terminal I/O port: 2333 Accept remote connection: yes Generate logfile: off Verify download: off Init regs on start: off Silent mode: on Single run mode: on Target connection timeout: 0 ms ------J-Link related settings------ J-Link Host interface: USB J-Link script: none J-Link settings file: none ------Target related settings------ Target device: cortex-m33 Target interface: SWD Target interface speed: 4000kHz Target endian: little GNU gdb (crosstool-NG 1.24.0.212_d7da3a9) 9.2 Copyright (C) 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "--host=x86_64-build_pc-linux-gnu --target=arm-zephyr-eabi". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from /home/ted/projects/zephyr-based/z9/aws-iot-stand-alone/build/zephyr/zephyr.elf... Remote debugging using :2331 arch_cpu_idle () at /home/ted/projects/zephyr-based/z9/zephyr/arch/arm/core/aarch32/cpu_idle.S:107 107 cpsie i Resetting target Loading section rom_start, size 0x23c lma 0x20200 Loading section text, size 0x1cd4a lma 0x20440 Loading section .ARM.exidx, size 0x8 lma 0x3d18c Loading section initlevel, size 0x80 lma 0x3d194 Loading section sw_isr_table, size 0x208 lma 0x3d214 Loading section net_socket_register_area, size 0xc lma 0x3d41c Loading section log_const_sections, size 0xf0 lma 0x3d428 Loading section zephyr_dbg_info, size 0x3c lma 0x3d518 Loading section device_handles, size 0x38 lma 0x3d554 Loading section rodata, size 0x554c lma 0x3d590 Loading section datas, size 0x3e0 lma 0x42af4 Loading section devices, size 0xa8 lma 0x42ed4 Loading section _static_thread_data_area, size 0x60 lma 0x42f7c Loading section k_heap_area, size 0x30 lma 0x42fdc Loading section k_mutex_area, size 0xb4 lma 0x4300c Loading section k_msgq_area, size 0x68 lma 0x430c0 Loading section k_sem_area, size 0x60 lma 0x43128 Loading section net_if_area, size 0x4 lma 0x43188 Loading section net_if_dev_area, size 0x1c lma 0x4318c Start address 0x00026050, load size 143238 Transfer rate: 6358 KB/sec, 5305 bytes/write. (gdb)
Many options given to `openocd` here but not an obvious clue from where `openocd` config files are read and parsed.