Semihosting scanf() broken with VScode

dzidmail · July 20, 2023, 11:43am

What is interpreter-exec console to appear on target’s stdin?
Extra strings make difficult to use scanf(), etc.

Notably, this is not happening when running pio debug --interface=gdb -x .pioinit, however, this one is also not completely free of issue, because after pressing q, the stdin receives “pio_reset_run_target q”.

I think it is coming either from platformio-vscode-debug or VScode debug adapter.
The only thing that makes me think maybe OpenOCD is involved somehow is that ststm32@16 behaves differently than ststm32@15.6, i.e. with v15.6 I get lines of extra garbage characters on stdin.

Extra details here:

github.com/platformio/platformio-core

Semihosting stdin spammed with internal strings - scanf() not usable

opened 10:35PM - 11 May 23 UTC

dzid26

help wanted debugging

What kind of issue is this? ### Configuration **Operating system**: Win11 … **PlatformIO Version** (`platformio --version`): 6.1.7 ### Description of the problem I didn't have much luck making `scanf()` usable. It is producing a lot of extra characters when using Platformio [semihosting](https://github.com/platformio/platformio-core/issues/3516). I have a suspicion it has something to do with `monitor arm semihosting_fileio enable`, as without and custom external openOCD terminal, the behavior is fine. #### Steps to Reproduce 1. Clone https://github.com/dzid26/STM32_BluePill_Semihosting.git 2. Debug F5, 3. Continue F5 4. Type something in Debug Console ### Actual Results In debug console, I typed 6 and Enter and got this. ``` Processing bluepill_f103c8 (platform: ststm32; board: bluepill_f103c8; framework: cmsis) -------------------------------------------------------------------------------- Verbose mode can be enabled via `-v, --verbose` option CONFIGURATION: https://docs.platformio.org/page/boards/ststm32/bluepill_f103c8.html PLATFORM: ST STM32 (15.4.1) > BluePill F103C8 HARDWARE: STM32F103C8T6 72MHz, 20KB RAM, 64KB Flash DEBUG: Current (stlink) External (blackmagic, cmsis-dap, jlink, stlink) PACKAGES: - framework-cmsis @ 2.50501.200527 (5.5.1) - framework-cmsis-stm32f1 @ 4.3.1 - tool-ldscripts-ststm32 @ 0.2.0 - toolchain-gccarmnoneeabi @ 1.70201.0 (7.2.1) Hello, world 6 24-interpreter-exec console "6" ��r� ��r�04F17�06� c�� o�F��IFPF��010��00�02�21#03` F26��0000 -��CaF�F)H00!25F��04F*F00!8F��c3425� F��34�&�F0FIF��06F0F��-�03(02�038�B� F��O��4 F03��04" F �0201��G�03(�ݝ�040S+�ѝ�050H+�ѝ�060F+�ѝ�a0B+��01"AF F��J�00(��*F9F F��)�05F F��(F��04F��31007�00!01" M L01�)`"`��00(aݝ�04003�010203�0203*`#`03�0�03m00;m00_m000000000000000000000000000000000000000000000000000000000000000000�0300000000000000000000040000pio_reset_run_target -gdb-exit ``` Sometimes it is less crazy and it would be just `interpreter-exec console "6"` If I use `c = scanf("%c", &c);` instead of `c = getchar();`, there is bunch of 0101: ``` 01010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101 ``` ### Expected Results This is what I get if use: ``` debug_extra_cmds = monitor arm semihosting enable debug_tool = custom debug_port = :3333 ``` OpenOCD terminal: ``` Executing task: cd ~/.platformio/packages/tool-openocd && bin/openocd -f scripts/interface/stlink.cfg -c 'set CPUTAPID 0' -f target/stm32f1x.cfg xPack OpenOCD x86_64 Open On-Chip Debugger 0.11.0+dev (2021-10-16-21:19) Licensed under GNU GPL v2 For bug reports, read http://openocd.org/doc/doxygen/bugs.html 0 Info : auto-selecting first available session transport "hla_swd". To override use 'transport select <transport>'. Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD Info : DEPRECATED target event trace-config; use TPIU events {pre,post}-{enable,disable} Info : Listening on port 6666 for tcl connections Info : Listening on port 4444 for telnet connections Info : clock speed 1000 kHz Info : STLINK V2J34M25 (API v2) VID:PID 0483:374B Info : Target voltage: 3.238046 Info : stm32f1x.cpu: Cortex-M3 r1p1 processor detected Info : stm32f1x.cpu: target has 6 breakpoints, 4 watchpoints Info : Listening on port 3333 for gdb connections Info : accepting 'gdb' connection on tcp/3333 Info : device id = 0x20036410 Info : flash size = 64kbytes target halted due to debug-request, current mode: Thread xPSR: 0x01000000 pc: 0x0800015c msp: 0x20005000 target halted due to debug-request, current mode: Thread xPSR: 0x01000000 pc: 0x0800015c msp: 0x20005000 target halted due to debug-request, current mode: Thread xPSR: 0x01000000 pc: 0x0800015c msp: 0x20005000 semihosting is enabled Hello, world 6 Warn : keep_alive() was not invoked in the 1000 ms timelimit. GDB alive packet not sent! (12230 ms). Workaround: increase "set remotetimeout" in GDB 6 6 Warn : keep_alive() was not invoked in the 1000 ms timelimit. GDB alive packet not sent! (5189 ms). Workaround: increase "set remotetimeout" in GDB 6 5 8 u w q Warn : keep_alive() was not invoked in the 1000 ms timelimit. GDB alive packet not sent! (1310 ms). Workaround: increase "set remotetimeout" in GDB q q Warn : keep_alive() was not invoked in the 1000 ms timelimit. GDB alive packet not sent! (1074 ms). Workaround: increase "set remotetimeout" in GDB q q q ``` ### If problems with PlatformIO Build System: **The content of `platformio.ini`:** ```ini ; PlatformIO Project Configuration File ; ; Build options: build flags, source filter ; Upload options: custom upload port, speed and extra flags ; Library options: dependencies, extra library storages ; Advanced options: extra scripting ; ; Please visit documentation for the other options and examples ; https://docs.platformio.org/page/projectconf.html [env:bluepill_f103c8] platform = ststm32 board = bluepill_f103c8 framework = cmsis ; Add The following lines of code to your project's platformio.ini file. upload_protocol = stlink upload_flags = -c set CPUTAPID 0 ; Allow Original and Clone STM32 to be detected by OpenOCD debugger. debug_build_flags = -O0 -ggdb3 ; Apply no optimization to the code written. ;debug_init_break = tbreak Reset_Handler ; Uncomment to activate: Adds a break point in the reset handler. ; ============ Enable Arm Semihosting in debugger to show logs ============= ; Add The following code lines to enable semihosting feature. ; To disable semihosting please comment all of the following code lines by adding semicolon ";" before each one: extra_scripts = extra_script.py ; The "extra_script.py" file must be located in the main project folder build_unflags = --specs=nosys.specs -lnosys debug_extra_cmds = monitor arm semihosting enable monitor arm semihosting_fileio enable debug_tool = stlink ; =========================================================================== ``` **Source file to reproduce issue:** ```cpp initialise_monitor_handles(); /* This Function MUST come before the first printf() */ printf("Hello, world\n"); /* IMPORTANT: Always use the "\n" newline character at the end of each string to be printed using printf() function when using semihosting */ int c; do{ //wait for the user c = getchar(); (void) printf("%c", c); if(c == '@') break; }while(1); ``` ### Additional info

dzidmail · July 20, 2023, 12:09pm

Btw, it’s not the only case that causes the gdb commands to appear on stdin.
Pressing all sort of debugger controls send the commands to stdin too.
Here is a test of debug controls when waiting for user input - in short, controls don’t work when scanf() is waiting for input and instead all debugger actions end up on stdin:

Processing bluepill_f103c8 (platform: ststm32@16; board: bluepill_f103c8; framework: cmsis)
--------------------------------------------------------------------------------
Verbose mode can be enabled via `-v, --verbose` option
CONFIGURATION: https://docs.platformio.org/page/boards/ststm32/bluepill_f103c8.html
PLATFORM: ST STM32 (16.0.0) > BluePill F103C8
HARDWARE: STM32F103C8T6 72MHz, 20KB RAM, 64KB Flash
DEBUG: Current (stlink) External (blackmagic, cmsis-dap, jlink, stlink)
PACKAGES:
 - framework-cmsis @ 2.50501.200527 (5.5.1)
 - framework-cmsis-stm32f1 @ 4.3.1
 - tool-ldscripts-ststm32 @ 0.2.0
 - toolchain-gccarmnoneeabi @ 1.70201.0 (7.2.1)
LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf
LDF Modes: Finder ~ chain, Compatibility ~ soft
Found 0 compatible libraries
Scanning dependencies...
No dependencies
Building in debug mode
Checking size .pio\build\bluepill_f103c8\firmware.elf
Advanced Memory Usage is available via "PlatformIO Home > Project Inspect"
RAM:   [          ]   1.6% (used 328 bytes from 20480 bytes)
Flash: [=         ]  10.4% (used 6788 bytes from 65536 bytes)
========================= [SUCCESS] Took 0.81 seconds =========================
Reading symbols from c:\Users\dzidm\Downloads\STM32_BluePill_Semihosting\.pio\build\bluepill_f103c8\firmware.elf...
done.
PlatformIO Unified Debugger -> https://bit.ly/pio-debug
PlatformIO: debug_tool = stlink
PlatformIO: Initializing remote target...
xPack Open On-Chip Debugger 0.12.0-01004-g9ea7f3d64-dirty (2023-01-30-15:04)
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
hla_swd
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
none separate

Info : tcl server disabled
Info : telnet server disabled
Info : clock speed 1000 kHz
Info : STLINK V2J34M25 (API v2) VID:PID 0483:374B
Info : Target voltage: 3.235938
Info : [stm32f1x.cpu] Cortex-M3 r1p1 processor detected
Info : [stm32f1x.cpu] target has 6 breakpoints, 4 watchpoints
Info : starting gdb server for stm32f1x.cpu on pipe
Info : accepting 'gdb' connection from pipe
[stm32f1x.cpu] halted due to breakpoint, current mode: Thread
xPSR: 0x01000000 pc: 0x08001502 msp: 0x20004f70
Info : device id = 0x20036410
Info : flash size = 64 KiB
0x08001502 in _swiread ()
[stm32f1x.cpu] halted due to debug-request, current mode: Thread
xPSR: 0x01000000 pc: 0x0800015c msp: 0x20005000
Loading section .isr_vector, size 0x10c lma 0x8000000
Loading section .text, size 0x192c lma 0x800010c
Loading section .rodata, size 0xe8 lma 0x8001a38
Loading section .init_array, size 0x4 lma 0x8001b20
Loading section .fini_array, size 0x4 lma 0x8001b24
Loading section .data, size 0x70 lma 0x8001b28
[stm32f1x.cpu] halted due to debug-request, current mode: Thread
xPSR: 0x01000000 pc: 0x0800015c msp: 0x20005000
Start address 0x800015c, load size 7064
Transfer rate: 12 KB/sec, 1177 bytes/write.
[stm32f1x.cpu] halted due to debug-request, current mode: Thread
xPSR: 0x01000000 pc: 0x0800015c msp: 0x20005000
[stm32f1x.cpu] halted due to debug-request, current mode: Thread
xPSR: 0x01000000 pc: 0x0800015c msp: 0x20005000
Temporary breakpoint 1 at 0x8000266: file src\main.c, line 66.
semihosting is enabled
semihosting fileio is enabled
PlatformIO: Initialization completed
PlatformIO: Resume the execution to `debug_init_break = tbreak main`
PlatformIO: More configuration options -> https://bit.ly/pio-debug
Note: automatically using hardware breakpoints for read-only addresses.

Temporary breakpoint 1, main () at src\main.c:66
66	    initialise_monitor_handles();   /* This Function MUST come before the first printf() */
Hello, world
Press key
Additonally we get garbage strings when controlling debugger with gui

24-interpreter-exec console "Additonally we get garbage strings when controlling debugger with gui"Option 
Press key
E.g. adding a breakpoint
25-interpreter-exec console "E.g. adding a breakpoint"Option 00
Press key
26-exec-interruptOption 00
Press key
Or pausing the programm
27-interpreter-exec console "Or pausing the programm"Option 00
Press key
28-exec-interrupt --thread 1Option 00
Press key
It actually didn't pause, but it will if pause is pressed again
29-interpreter-exec console "It actually didn't pause, but it will if pause is pressed again"Option 00
Press key
30-exec-interrupt --thread 1Option 00
Press key
31-exec-interrupt --thread 1Option 00
Press key
32-exec-interrupt --thread 1Option 00
Press key
Or not...
33-interpreter-exec console "Or not..."Option 00
Press key
Let's try stepping
34-interpreter-exec console "Let's try stepping"Option 00
Press key
35-exec-interruptOption 00
Press key
36-interpreter-exec console ""Option 00
Press key
37-interpreter-exec console ""Option 00
Press key
38-interpreter-exec console ""Option 00
Press key
Nope, I guess controls don't work when scanf is consuming it
39-interpreter-exec console "Nope, I guess controls don't work when scanf is consuming it"Option 00
Press key
Let's stop the program. I know it will not stop after single press...
40-interpreter-exec console "Let's stop the program. I know it will not stop after single press..."Option 00
Press key
pio_reset_run_targetOption 00
Press key
-gdb-exitOption 00
Press key
pio_reset_run_targetOption 00
Press key
-gdb-exitOption 00
Press key
Canceled
Canceled
Canceled
Canceled
Canceled
Canceled
Canceled
Canceled
Canceled
Canceled

maxgerhardt · July 21, 2023, 9:24am

If it works on the CLI but not in the VSCode GUI, you might want to open an issue at

dzidmail · July 21, 2023, 4:49pm

Part of the issue still relates to CLI:

so I am going to leave that one open.

But as suggested I created a new issue for the vscode-IDE:

github.com/platformio/platformio-vscode-ide

Semihosting target stdin littered with debugger commands

opened 04:44PM - 21 Jul 23 UTC

dzid26

The problem occurs when debugging with VScode. When debugging with CLI it is m…ostly ok. To reproduce: 1. clone https://github.com/dzid26/platformio-examples/blob/develop/unit-testing/semihosting/ 2. press F5 and then continue into main 3. type some character to the debug console, (or set a breakpoint) Behavior: Target receives internal debugger commands, eg. `interpreter-exec console` or `exec-interruptOption`. <img width="471" alt="image" src="https://github.com/platformio/platformio-vscode-ide/assets/841061/162dcdab-21a6-41fc-b9a6-c7074bd92ba0)"> I tried to debug the issue but only got so far as I don't see the internals of the Unified Debugger. I created another issue for this problem for Pio core because I wasn't sure where the issue originated from.: https://github.com/platformio/platformio-core/issues/4621