How to use the debug methods {#debug_methods}

At the FreeRTOS SDK,there are some debug methods supported.You could to use them to debug your program and find out the problem's root cause helpful.

debug methods list

GCC option

finstrument-functions option

  • function:the linker link a function:it will invoke a hook function when enter the function,then invoke another function when exit the function.
  • The hook function has its fixed name _cyg_profile_func_enter and __cyg_profile_func_exit.
  • To be avoid invoke itself,the hook function need add no_instrument_function attribute.
  • example
  void __attribute__((no_instrument_function))__cyg_profile_func_enter(void *this, void *call)
  {
        printf("enter func:0x%x, caller:0x%x\n", this, call);
  }

  void __attribute__((no_instrument_function))__cyg_profile_func_exit(void *this, void *call)

  {
        printf("exit func:0x%x, caller:0x%x\n", this, call);
  }
  • cmake option for module:set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -finstrument-functions")
  • cmake option for function:set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -finstrument-functions-exclude-function-list=instrument_function_hide")
  • cmake option for file:set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -finstrument-functions-exclude-file-list=main.c")

__builtin_return_address function

  • function protype:void * __builtin_return_address (unsigned int level)
  • useage:This function returns the return address of the current function, or of one of its callers
  • note:It is used to 0 level to get return address of current function,other level is always return 0

CLI command

task-stats command

  • enable the CLI support

  • type task-stats command:return the content of bellow title:

    name number state priority stack_depth stack_watermark run(ms) run(percent)

  • name:task of name

  • number:task id

  • state:task status；X（running），B（blocked），R（ready to schedule），D（deleted）S（suspend）

  • priority:priority of task

  • stack_depth:stack depth of task

  • stack_watermark：the watermark of task stack；

  • run(ms)：running time of this task；

  • run(percent) ：running percent time of this task；

backtrace

Step 1: How to enable Backtrace

Choose your project

If you already know the ARCH, SOC, BOARD and PRODUCT,

you could specify them by the command line parameters.

source scripts/env.sh [ARCH] [SOC] [BOARD] [PRODUCT]

For ARCH arm64, SOC a1, BOARD ad401_a113l, PRODUCT speaker, you could type the following command.

source scripts/env.sh arm64 a1 ad401_a113l speaker

Otherwise, you can choose the project interactively by the following command.

source scripts/env.sh

Config your project

make menuconfig

steps following: Libs Options -> Backtrace Support

Step 2: How to enable sym table print

If you use the following command:

make

When an exception occurs, the output format is as follows:

ESR:     96000007
SPSR:    20000004
ELR:     13cb4
LR:      13cb4
========== Call stack ==========
[<0000000000013cb4>] N/A
[<000000000001b094>] N/A
[<000000000001c194>] N/A
[<fffffffffffffffc>] N/A
==========    End    ==========

If you use the following command:

make backtrace

When an exception occurs, the output format is as follows:

ESR:     96000007
SPSR:    20000004
ELR:     13cb4
LR:      13cb4
========== Call stack ==========
[<0000000000013cb4>] cmd_read32+0x154/0x250
[<000000000001b094>] FreeRTOS_CLIProcessCommand+0xa4/0x3b0
[<000000000001c194>] FreeRTOS_CLIEnterConsoleLoop+0x294/0x740
[<fffffffffffffffc>] N/A
==========    End    ==========

Step 3: How to via backtrace help for debug

Backtrace default used when program crash (Asynchronous exception)) .

Also you can use to other place like this:

print current context stack when dump_stack() called by assertion.

version management

when you compile your project complete,RTOS SDK will collect git information and general a report sheet in a output file.

source code

The file's path is output/project_fullname/freertos/sdk_ver.h.You can use them to trace your source code version.The sheet is follow:

    [cm_hash  remote_name  branch      ]
    [f7e725c  boar riscv   amlogic-dev ]
    [c9d7923  arch riscv   (HEAD       ]
    [db5a75b  soc  riscv   (HEAD       ]
    [cfc1e49  scripts      (HEAD       ]
    [a341cbe  libc         (HEAD       ]
    [e72fb29  freertos     (HEAD       ]
    [601c9d0  prod aocpu   (HEAD       ]
    [c6e9858  build        (HEAD       ]
    [46573f9  drivers_aocp (HEAD       ]
  • col_1st:the locate newest commit short hash number
  • col_2nd:remote git repository name,first section+last section composite
  • col_3rd:locate branch name.HEAD,no means that not to build a branch at local

binary file

For binary file,it will enable the switch to output version message

  • support arch:arm64/riscv
  • select VERSION_FULL_INFO in the board name's Kconfig
  • make distclean && make

module size statistics

when you compile your project complete,it will calculate the module size and report them in a output file.

  • support arch:arm64/riscv/xtensa
  • statistics file path:output/project_fullname/freertos/freertos_module_info.txt
  • report contents:
    • customer section size
    • module size summary
    • binary size summary
  • notes：There is few data error cause that xcc map file not to describe align data.It is less than 10 as far as we know
  • more details in freertos_module_info.txt