vscode cortex-debug launch.json gdb external configuration, how to have the right parameters

RE: vscode cortex-debug launch.json gdb external configuration, how to have the right parameters

Håkon Alseth — Mon, 09 Jan 2023 13:59:21 GMT

Hi Matthieu,

[quote user="mattfavre"]As far as i understand, GDB connection to the target and GDB commands are working![/quote]

Yes, gdb is working as it should!

[quote user="mattfavre"]At the moment, i am flashing the MCU manually with the nrf programmer.

how can i automate this with gdb? (load command doesn't seems to work...)

[/quote]

"load" can be problematic if you have multi-image builds (mcuboot + app for instance).

this is because it only updates the application part, and not the image as a whole.

nrfjprog should have support for remote connections now, as shown in the release notes for v10.15.0:

- (nrfjprog.exe) Added option "--ip" and "--port" for connecting to a network enabled debugger.

You could try to use that. Alternative can be to use JLink.exe (J-Link commander) to remotely connect and download the binary.

Kind regards,

Håkon

RE: vscode cortex-debug launch.json gdb external configuration, how to have the right parameters

mattfavre — Mon, 09 Jan 2023 08:06:24 GMT

Hi Håkon,
Thanks for the insights it helps a lot, here is what I did and the actual state:

What I did: (All actions are made in the docker devcontainer)

Reinstalled the ARM GNU toolchain (x86_64 Linux hosted cross toolchains) from https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
Change the compilation optimisation flag in makefile from -O0 to -Og and recompiled everything
```
#OPT_FLAG   := -O0
OPT_FLAG   := -Og
DEBUG_FLAG := -g3
```
Recompiled the firmware and flashed the target

Tried a remote command line GDB debug session, it seems it works, here is the outputs:

Terminal output (from devcontainer)

arm-none-eabi-gdb application.out 
GNU gdb (Arm GNU Toolchain 12.2.Rel1 (Build arm-12.24)) 12.1.90.20221210-git
Copyright (C) 2022 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-pc-linux-gnu --target=arm-none-eabi".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://bugs.linaro.org/>.
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 application.out...
(gdb) target remote host.docker.internal:2331
Remote debugging using host.docker.internal:2331
0xdeadbeee in ?? ()
(gdb) print /x idle_state_handle
$1 = 0x8
(gdb) print /x idle_state_handle
$2 = 0x8
(gdb) print /x idle_state_handle
$3 = 0x8
(gdb) b main
Breakpoint 1 at 0x3b510: file application/application/main.c, line 65.
(gdb) monitor reset
Resetting target
(gdb) c
Continuing.

Breakpoint 1, main () at application/application/main.c:65
65      {
(gdb) backtrace
#0  main () at application/application/main.c:65
(gdb)

SEGGER J-Link GDB Server Log

Connected to 127.0.0.1
Reading all registers
ERROR: Cannot read register 0 (R0) while CPU is running
ERROR: Cannot read register 1 (R1) while CPU is running
ERROR: Cannot read register 2 (R2) while CPU is running
ERROR: Cannot read register 3 (R3) while CPU is running
ERROR: Cannot read register 4 (R4) while CPU is running
ERROR: Cannot read register 5 (R5) while CPU is running
ERROR: Cannot read register 6 (R6) while CPU is running
ERROR: Cannot read register 7 (R7) while CPU is running
ERROR: Cannot read register 8 (R8) while CPU is running
ERROR: Cannot read register 9 (R9) while CPU is running
ERROR: Cannot read register 10 (R10) while CPU is running
ERROR: Cannot read register 11 (R11) while CPU is running
ERROR: Cannot read register 12 (R12) while CPU is running
ERROR: Cannot read register 13 (R13) while CPU is running
ERROR: Cannot read register 14 (R14) while CPU is running
ERROR: Cannot read register 15 (R15) while CPU is running
ERROR: Cannot read register 16 (XPSR) while CPU is running
ERROR: Cannot read register 17 (MSP) while CPU is running
ERROR: Cannot read register 18 (PSP) while CPU is running
ERROR: Cannot read register 24 (PRIMASK) while CPU is running
ERROR: Cannot read register 25 (BASEPRI) while CPU is running
ERROR: Cannot read register 26 (FAULTMASK) while CPU is running
ERROR: Cannot read register 27 (CONTROL) while CPU is running
ERROR: Cannot read register 32 (FPSCR) while CPU is running
ERROR: Cannot read register 33 (FPS0) while CPU is running
ERROR: Cannot read register 34 (FPS1) while CPU is running
ERROR: Cannot read register 35 (FPS2) while CPU is running
ERROR: Cannot read register 36 (FPS3) while CPU is running
ERROR: Cannot read register 37 (FPS4) while CPU is running
ERROR: Cannot read register 38 (FPS5) while CPU is running
ERROR: Cannot read register 39 (FPS6) while CPU is running
ERROR: Cannot read register 40 (FPS7) while CPU is running
ERROR: Cannot read register 41 (FPS8) while CPU is running
ERROR: Cannot read register 42 (FPS9) while CPU is running
ERROR: Cannot read register 43 (FPS10) while CPU is running
ERROR: Cannot read register 44 (FPS11) while CPU is running
ERROR: Cannot read register 45 (FPS12) while CPU is running
ERROR: Cannot read register 46 (FPS13) while CPU is running
ERROR: Cannot read register 47 (FPS14) while CPU is running
ERROR: Cannot read register 48 (FPS15) while CPU is running
ERROR: Cannot read register 49 (FPS16) while CPU is running
ERROR: Cannot read register 50 (FPS17) while CPU is running
ERROR: Cannot read register 51 (FPS18) while CPU is running
ERROR: Cannot read register 52 (FPS19) while CPU is running
ERROR: Cannot read register 53 (FPS20) while CPU is running
ERROR: Cannot read register 54 (FPS21) while CPU is running
ERROR: Cannot read register 55 (FPS22) while CPU is running
ERROR: Cannot read register 56 (FPS23) while CPU is running
ERROR: Cannot read register 57 (FPS24) while CPU is running
ERROR: Cannot read register 58 (FPS25) while CPU is running
ERROR: Cannot read register 59 (FPS26) while CPU is running
ERROR: Cannot read register 60 (FPS27) while CPU is running
ERROR: Cannot read register 61 (FPS28) while CPU is running
ERROR: Cannot read register 62 (FPS29) while CPU is running
ERROR: Cannot read register 63 (FPS30) while CPU is running
ERROR: Cannot read register 64 (FPS31) while CPU is running
ERROR: Cannot read register 33 (FPS0) while CPU is running
ERROR: Cannot read register 34 (FPS1) while CPU is running
ERROR: Cannot read register 35 (FPS2) while CPU is running
ERROR: Cannot read register 36 (FPS3) while CPU is running
ERROR: Cannot read register 37 (FPS4) while CPU is running
ERROR: Cannot read register 38 (FPS5) while CPU is running
ERROR: Cannot read register 39 (FPS6) while CPU is running
ERROR: Cannot read register 40 (FPS7) while CPU is running
ERROR: Cannot read register 41 (FPS8) while CPU is running
ERROR: Cannot read register 42 (FPS9) while CPU is running
ERROR: Cannot read register 43 (FPS10) while CPU is running
ERROR: Cannot read register 44 (FPS11) while CPU is running
ERROR: Cannot read register 45 (FPS12) while CPU is running
ERROR: Cannot read register 46 (FPS13) while CPU is running
ERROR: Cannot read register 47 (FPS14) while CPU is running
ERROR: Cannot read register 48 (FPS15) while CPU is running
ERROR: Cannot read register 49 (FPS16) while CPU is running
ERROR: Cannot read register 50 (FPS17) while CPU is running
ERROR: Cannot read register 51 (FPS18) while CPU is running
ERROR: Cannot read register 52 (FPS19) while CPU is running
ERROR: Cannot read register 53 (FPS20) while CPU is running
ERROR: Cannot read register 54 (FPS21) while CPU is running
ERROR: Cannot read register 55 (FPS22) while CPU is running
ERROR: Cannot read register 56 (FPS23) while CPU is running
ERROR: Cannot read register 57 (FPS24) while CPU is running
ERROR: Cannot read register 58 (FPS25) while CPU is running
ERROR: Cannot read register 59 (FPS26) while CPU is running
ERROR: Cannot read register 60 (FPS27) while CPU is running
ERROR: Cannot read register 61 (FPS28) while CPU is running
ERROR: Cannot read register 62 (FPS29) while CPU is running
ERROR: Cannot read register 63 (FPS30) while CPU is running
ERROR: Cannot read register 64 (FPS31) while CPU is running
Read 4 bytes @ address 0xDEADBEEE (Data = 0x00000000)
Read 1 bytes @ address 0x0003B4F0 (Data = 0x08)
Read 1 bytes @ address 0x0003B4F0 (Data = 0x08)
Read 1 bytes @ address 0x0003B4F0 (Data = 0x08)
Read 2 bytes @ address 0x0003B510 (Data = 0xB508)
Received monitor command: reset
Resetting target
Setting breakpoint @ address 0x0003B510, Size = 2, BPHandle = 0x0002
Starting target CPU...
...Breakpoint reached @ address 0x0003B510
Reading all registers
Removing breakpoint @ address 0x0003B510, Size = 2
Read 4 bytes @ address 0x0003B510 (Data = 0x4A22B508)
Read 4 bytes @ address 0x000272E2 (Data = 0xF957F023)
Reading 64 bytes @ address 0x00027280
Read 4 bytes @ address 0x000272F4 (Data = 0x20040000)
Read 4 bytes @ address 0x000272EA (Data = 0x00000008)

As far as i understand, GDB connection to the target and GDB commands are working!

I overrid some monitor commands based on

the supported monitor commands by J-LinkGDBServer https://wiki.segger.com/J-Link_GDB_Server
a comparison of the commands sent by the marus25 extension when using external type or jlink type

{
            "cwd": "${workspaceFolder}",
            "executable": "${workspaceFolder}/application/_build/pod_application.out",
            "name": "Debug devcontainer arm-none-eabi-gdb",
            "request": "launch",
            "type": "cortex-debug",
            "servertype": "external",
            "gdbPath": "/opt/gcc-arm-none-eabi/bin/arm-none-eabi-gdb",
            "gdbTarget": "host.docker.internal:2331",
            "device": "NRF52840_XXAA",
            "runToEntryPoint": "main",
            "svdFile": "${workspaceRoot}/nrf5_sdk/modules/nrfx/mdk/nrf52840.svd",
            "overrideRestartCommands": [
                "monitor halt",
                "monitor reset"
            ],
            "overrideResetCommands": [
                "monitor reset"
            ],
            "preLaunchCommands": [
                "monitor reset"
            ],
            "postLaunchCommands": [
            ],
            "showDevDebugOutput": "both"
        },

With those adaptations, I can debug step by steps from the vscode interface

Question:

At the moment, i am flashing the MCU manually with the nrf programmer.
- how can i automate this with gdb? (load command doesn't seems to work...)
Any other suggestions to add functionalities, script automation or other way to do?

Thanks,

Matthieu

RE: vscode cortex-debug launch.json gdb external configuration, how to have the right parameters

Håkon Alseth — Tue, 03 Jan 2023 14:31:50 GMT

Hi,

Your log shows:

Cortex-Debug: VSCode debugger extension version 1.6.9 git(4c381ef). Usage info: https://github.com/Marus/cortex-debug#usage
Reading symbols from /usr/bin/objdump-multiarch --syms -C -h -w /workspaces/fw-pod/application/_build/pod_application.out
Reading symbols from /usr/bin/nm-multiarch --defined-only -S -l -C -p /workspaces/fw-pod/application/_build/pod_application.out
Launching GDB: /usr/bin/gdb-multiarch -q --interpreter=mi2
1-gdb-version
Error: /usr/bin/nm-multiarch failed! statics/global/functions may not be properly classified: Error: spawn /usr/bin/nm-multiarch ENOENT
    Expecting `nm` next to `objdump`. If that is not the problem please report this.
Error: objdump failed! statics/globals/functions may not be properly classified: Error: spawn /usr/bin/objdump-multiarch ENOENT    ENOENT means program not found. If that is not the issue, please report this problem.Finished reading symbols from objdump: Time: 15 ms
Finished reading symbols from nm: Time: 13 ms
-> =thread-group-added,id="i1"

I would recommend that you use arm-none-eabi instead of multiarch, to avoid such problems.

It seems that you initially break here:

GDB -> App: {"output":"","outOfBandRecord":[{"isStream":true,"type":"console","content":"73\t    APP_SCHED_INIT(SCHED_MAX_EVENT_DATA_SIZE, SCHED_QUEUE_SIZE);\n"}]}
73	    APP_SCHED_INIT(SCHED_MAX_EVENT_DATA_SIZE, SCHED_QUEUE_SIZE);

But, you do not show any info on how this is shown in vscode, so it is hard to say what can be the issue, given that you mention single-stepping and stopping on breakpoints as a problem.

[quote user=""]Some GDB commands are somehow not expected by the J-Link GDB server as seen in the logs:

Received monitor command: reset halt
Expected an decimal digit (0-9)
Any ideas regarding that?

[/quote]

Looks like the cortex m debug plugin issues a "monitor reset halt"

[quote user=""]

Do you have any inputs regarding the launch.json configuration and tools chosen?
- Is it a good option, should I change something?
Is there some pre/post debug sequences I should add/adapt?
- preLaunchCommands?
- postLaunchCommands?
- overrideResetCommands?
- overrideRestartCommands?
- postAttachCommands?
- postLaunchCommands?
- postResetCommands?
- ect...
Any other inputs?

[/quote]

First I would recommend that you, from the container, connect manually using gdb:

my-gdb path/to/.elf

And in gdb:

target remote ip:port

backtrace

print /x some_variable

b main # set breakpoint at main()

monitor reset

c # continue until breakpoint it hit

This is to verify that your debug connection is working. I haven't used multiarch-gdb myself, so I cannot verify if it actually works as intended with cortex m.

Kind regards,

Håkon

RE: vscode cortex-debug launch.json gdb external configuration, how to have the right parameters

mattfavre — Tue, 03 Jan 2023 12:18:39 GMT

One more main issue is that

step by step debugging and
stop at main after debug launch

don't work.