Lab36: ELF

預期目標

• 在 STM32F429i Discovery</embedded/STM32F429>_ 開發簡易 ELF loader
• 學習 OpenOCD 和 gdb

預先準備

• 確認 $PATH 可找到 Lab 35</embedded/Lab35>_ 設定的 GNU Toolchain
  • arm-none-eabi-gcc -v 預期輸出 4.8.3-11ubuntu1 一類包含 ubuntu 的字串
  • 若否，請重新設定 PATH 環境變數
• 確認 STM32F429i Discovery</embedded/STM32F429>_ 板子已經由 USB 線接上裝有 GNU/Linux 的開發環境，並確保 Lab 35</embedded/Lab35>_ 所提及的工具均已正確安裝，如 openocd 與 gdb

$ make oocd 參考執行結果:

.. code-block:: prettyprint

make[1]: Entering directory 'elfloader/app'
 CLEAN
 CC main.c
 CC start.c
 LINK app.elf
   text	   data	    bss	    dec	    hex	filename
    164	      8	      4	    176	     b0	app.elf
 Creating list...
make[1]: Leaving directory 'elfloader/app'
 Launch OpenOCD for stm32f4discovery
Open On-Chip Debugger 0.9.0-dev-00105-ge1bc7f4 (2014-08-08-20:38)
...
ELF: Scan ELF indexs...
ELF: Examining section 1 .text
ELF: Examining section 2 .rel.text
ELF: Examining section 3 .rodata
...
ELF: Examining section 11 .symtab
ELF: Examining section 12 .strtab
ELF: Done
ELF: Relocating section .text
ELF:  Offset   Info     Type             Name
ELF:  00000034 00001202 R_ARM_ABS32      i
...
ELF: Relocating section .rodata
ELF:  Offset   Info     Type             Name
ELF:  00000038 00001502 R_ARM_ABS32      banner
...
ELF:   symAddr=20000F48 relAddr=20000F8C
ELF:   R_ARM_ABS32 relocated is 0x20000F54
Hello world on Oct 30 2014 at 17:28:11 (0)
...
Done
semihosting: *** application exited ***

參考資訊

• BeagleBoard OpenOCD<http://elinux.org/BeagleBoardOpenOCD>_
• GDB and OpenOCD<http://openocd.sourceforge.net/doc/html/GDB-and-OpenOCD.html>_