32.2. rvbacktrace_no_fp

32.2.1. Overview

This example demonstrates the use of instruction parsing to perform stack backtracking for interrupts, function calls and exception on a riscv32 machine.

32.2.2. Hardware Configuration

No special configuration is required.

32.2.3. Running the example

Once this program runs correctly, the function call information corresponding to the situation will be output on the console. In case of an exception, the register values saved in the stack when the exception occurs will be output.

  • interrupt

ENTER ISR

---- RV_Backtrace Call Frame Start: ----
[0]Stack interval :[0x87f10 - 0x87f50]  ra 0x800086c6
[1]Stack interval :[0x87f50 - 0x87f60]  ra 0x80005f82
[2]Stack interval :[0x87f60 - 0x87f70]  ra 0x22c
[3]Stack interval :[0x87f70 - 0x87f80]  ra 0x274
[4]Stack interval :[0x87f80 - 0x87fd0]  ra 0x80006084
[5]Stack interval :[0x87fd0 - 0x87ff0]  ra 0x80006406
[6]Stack interval :[0x87ff0 - 0x88000]  ra 0x8000305a

addr2line -e xxx.elf -a -f 800086c6 80005f82 22c 274 80006084 80006406 8000305a

  • caller and callee

F[function_recursion]: recursion cycle[1]

---- RV_Backtrace Call Frame Start: ----
[0]Stack interval :[0x87f60 - 0x87fa0]  ra 0x800086c6
[1]Stack interval :[0x87fa0 - 0x87fb0]  ra 0x80005f06
[2]Stack interval :[0x87fb0 - 0x87fd0]  ra 0x80006098
[3]Stack interval :[0x87fd0 - 0x87ff0]  ra 0x80006406
[4]Stack interval :[0x87ff0 - 0x88000]  ra 0x8000305a

addr2line -e xxx.elf -a -f 800086c6 80005f06 80006098 80006406 8000305a
---- RV_Backtrace Call Frame End:----

F[function_recursion]: recursion cycle[2]

---- RV_Backtrace Call Frame Start: ----
[0]Stack interval :[0x87f40 - 0x87f80]  ra 0x800086c6
[1]Stack interval :[0x87f80 - 0x87f90]  ra 0x80005f06
[2]Stack interval :[0x87f90 - 0x87fb0]  ra 0x80005f0e
[3]Stack interval :[0x87fb0 - 0x87fd0]  ra 0x80006098
[4]Stack interval :[0x87fd0 - 0x87ff0]  ra 0x80006406
[5]Stack interval :[0x87ff0 - 0x88000]  ra 0x8000305a

addr2line -e xxx.elf -a -f 800086c6 80005f06 80005f0e 80006098 80006406 8000305a
---- RV_Backtrace Call Frame End:----

F[function_recursion]: recursion cycle[3]

---- RV_Backtrace Call Frame Start: ----
[0]Stack interval :[0x87f20 - 0x87f60]  ra 0x800086c6
[1]Stack interval :[0x87f60 - 0x87f70]  ra 0x80005f06
[2]Stack interval :[0x87f70 - 0x87f90]  ra 0x80005f0e
[3]Stack interval :[0x87f90 - 0x87fb0]  ra 0x80005f0e
[4]Stack interval :[0x87fb0 - 0x87fd0]  ra 0x80006098
[5]Stack interval :[0x87fd0 - 0x87ff0]  ra 0x80006406
[6]Stack interval :[0x87ff0 - 0x88000]  ra 0x8000305a

addr2line -e xxx.elf -a -f 800086c6 80005f06 80005f0e 80005f0e 80006098 80006406 8000305a
---- RV_Backtrace Call Frame End:----

F[function_recursion]: recursion cycle[4]

---- RV_Backtrace Call Frame Start: ----
[0]Stack interval :[0x87f00 - 0x87f40]  ra 0x800086c6
[1]Stack interval :[0x87f40 - 0x87f50]  ra 0x80005f06
[2]Stack interval :[0x87f50 - 0x87f70]  ra 0x80005f0e
[3]Stack interval :[0x87f70 - 0x87f90]  ra 0x80005f0e
[4]Stack interval :[0x87f90 - 0x87fb0]  ra 0x80005f0e
[5]Stack interval :[0x87fb0 - 0x87fd0]  ra 0x80006098
[6]Stack interval :[0x87fd0 - 0x87ff0]  ra 0x80006406
[7]Stack interval :[0x87ff0 - 0x88000]  ra 0x8000305a

addr2line -e xxx.elf -a -f 800086c6 80005f06 80005f0e 80005f0e 80005f0e 80006098 80006406 8000305a

  • exception

GET FAULT ADDRESS, ENTER TRAP

---- RV_Backtrace In Trap Start: ----
[0]Stack interval :[0x87e80 - 0x87ec0]  ra 0x800086e0
[1]Stack interval :[0x87ec0 - 0x87ee0]  ra 0x80005f66
[2]Stack interval :[0x87ee0 - 0x87f00]  ra 0x3cc
[3]Stack interval :[0x87f00 - 0x87f80]  ra 0x80005f2a
[4]Stack interval :[0x87f80 - 0x87fb0]  ra 0x80005f48
[5]Stack interval :[0x87fb0 - 0x87fd0]  ra 0x8000609a
[6]Stack interval :[0x87fd0 - 0x87ff0]  ra 0x80006406
[7]Stack interval :[0x87ff0 - 0x88000]  ra 0x8000305a

addr2line -e xxx.elf -a -f 800086e0 80005f66 3cc 80005f2a 80005f48 8000609a 80006406 8000305a
---- RV_Backtrace In Trap End:----

---- RV Core Dump:----
    mcause:       0x5
    mepc:                 0x80005f2c
    ra:           0x80005f2a
    t0:           0x0
    t1:           0x87ecc
    t2:           0x20
    a0:           0x1e
    a1:           0xa
    a2:           0x1e
    a3:           0xf0040000
    a4:           0x6e1
    a5:           0xffffffff
    a6:           0x8000ea18
    a7:           0x73
    t3:           0x271a
    t4:           0x10bacb8
    t5:           0x3acb8
    t6:           0x10bf9e0

Note

  • The first stack frame of the print information is the stack frame of the stack backtrace API, and the call starts at [1]Stack interval .

  • In exception situations, rvbacktrace_trap() needs to be used. For interrupts and function calls, rvbacktrace() is used.

  • This component is generally used for software debugging. It is recommended to use it under the debug level.

  • The method of rvbacktrace through instruction parsing is applicable to the situation where instructions are in a separate text segment. However, the presence of gaps between instructions or RODATA may lead to incorrect instruction parsing and ultimately result in the failure of rvbacktrace.

  • To view the call chain of function names, the addr2line tool needs to be used

    addr2line -e xxx.elf -a -f <addr1> <addr2> ...