kopia lustrzana https://github.com/stlink-org/stlink
64 wiersze
2.0 KiB
Plaintext
64 wiersze
2.0 KiB
Plaintext
HOWTO
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=====
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To run the gdb server, do (you do not need sudo if you have set up
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permissions correctly):
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$ make -C build && sudo ./build/st-util 1234 /dev/sg1
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Then, in gdb:
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(gdb) target remote :1234
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Have fun!
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Resetting the chip from GDB
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===========================
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You may reset the chip using GDB if you want. You'll need to use `target
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extended-remote' command like in this session:
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(gdb) target extended-remote localhost:1111
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Remote debugging using localhost:1111
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0x080007a8 in _startup ()
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(gdb) kill
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Kill the program being debugged? (y or n) y
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(gdb) run
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Starting program: /home/whitequark/ST/apps/bally/firmware.elf
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Remember that you can shorten the commands. `tar ext :1111' is good enough
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for GDB.
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Running programs from SRAM
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==========================
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You can run your firmware directly from SRAM if you want to. Just link
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it at 0x20000000 and do
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(gdb) load firmware.elf
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It will be loaded, and pc will be adjusted to point to start of the
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code, if it is linked correctly (i.e. ELF has correct entry point).
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Writing to flash
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================
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The GDB stub ships with a correct memory map, including the flash area.
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If you would link your executable to 0x08000000 and then do
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(gdb) load firmware.elf
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then it would be written to the memory.
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FAQ
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===
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Q: My breakpoints do not work at all or only work once.
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A: Optimizations can cause severe instruction reordering. For example,
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if you are doing something like `REG = 0x100;' in a loop, the code may
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be split into two parts: loading 0x100 into some intermediate register
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and moving that value to REG. When you set up a breakpoint, GDB will
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hook to the first instruction, which may be called only once if there are
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enough unused registers. In my experience, -O3 causes that frequently.
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Q: At some point I use GDB command `next', and it hangs.
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A: Sometimes when you will try to use GDB `next' command to skip a loop,
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it will use a rather inefficient single-stepping way of doing that.
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Set up a breakpoint manually in that case and do `continue'.
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