[coreboot] Re: GDB stub & bootblock dependencies (CONFIG_IDT_IN_EVERY_STAGE=y)

[Lance Zhao]

Then those console.c and uart.h need to follow to include in every stage?

Samek, Jan  于2021年7月23日周五 上午12:15写道：
> Hello,
>
> I am currently developing on Intel TGLRVP-UP3, but this should be relevant
> for other TGL-based platforms and possibly all other that set
> CONFIG_IDT_IN_EVERY_STAGE=y:
>
> When I try to use the GDB stub for my debug attempts on TGL
> (CONFIG_GDB_STUB=y), I get the following 'undefined reference' errors
> during the bootblock linkage process:
>
> src/arch/x86/exception.c:225: undefined reference to `gdb_tx_byte'
> src/arch/x86/exception.c:225: undefined reference to `gdb_tx_byte'
> src/arch/x86/exception.c:225: undefined reference to `gdb_tx_byte'
> src/arch/x86/exception.c:230: undefined reference to `gdb_tx_flush'
> src/arch/x86/exception.c:230: undefined reference to `gdb_tx_flush'
> src/arch/x86/exception.c:230: undefined reference to `gdb_tx_flush'
> src/arch/x86/exception.c:235: undefined reference to `gdb_rx_byte'
> util/crossgcc/xgcc/bin/i386-elf-ld.bfd: src/arch/x86/exception.c:225:
> undefined reference to `gdb_tx_byte'
> util/crossgcc/xgcc/bin/i386-elf-ld.bfd: src/arch/x86/exception.c:225:
> undefined reference to `gdb_tx_byte'
> util/crossgcc/xgcc/bin/i386-elf-ld.bfd: src/arch/x86/exception.c:225:
> undefined reference to `gdb_tx_byte'
> util/crossgcc/xgcc/bin/i386-elf-ld.bfd: src/arch/x86/exception.c:225:
> undefined reference to `gdb_tx_byte'
> util/crossgcc/xgcc/bin/i386-elf-ld.bfd: src/arch/x86/exception.c:235:
> undefined reference to `gdb_rx_byte'
> util/crossgcc/xgcc/bin/i386-elf-ld.bfd: src/arch/x86/exception.c:235:
> undefined reference to `gdb_rx_byte'
> util/crossgcc/xgcc/bin/i386-elf-ld.bfd: src/arch/x86/exception.c:235:
> undefined reference to `gdb_rx_byte'
> util/crossgcc/xgcc/bin/i386-elf-ld.bfd: src/arch/x86/exception.c:235:
> undefined reference to `gdb_rx_byte'
>
> The gdb_*() functions used in exception.c are defined in
> src/console/console.c. Nevertheless, the problem with the functions in
> question is that they're defined under '#if CONFIG(GDB_STUB) &&
> (ENV_ROMSTAGE || ENV_RAMSTAGE)' which obviously doesn't allow them to be
> compiled into the bootblock code while they're unconditionally (there's
> only the IDT_IN_EVERY_STAGE condition) referenced in exception.c
>
> Looking at src/arch/x86/Makefile.inc (filtering out only the lines of
> interest), it's apparent that exception.c is linked in all stages when the
> IDT_IN_EVERY_STAGE option is set:
>
> 76:  bootblock-$(CONFIG_IDT_IN_EVERY_STAGE) += exception.c
> 111: verstage-$(CONFIG_IDT_IN_EVERY_STAGE) += exception.c
> 148: romstage-$(CONFIG_IDT_IN_EVERY_STAGE) += exception.c
> 187: postcar-$(CONFIG_IDT_IN_EVERY_STAGE) += exception.c
> 229: ramstage-y += exception.c
> 291: smm-$(CONFIG_IDT_IN_EVERY_STAGE) += exception.c
>
> The behavior appears in revision b90aba43c1405d3d2cb7cba05e68906e979dcda3
> (master).
>
> To reproduce,
> run 'make menuconfig',
> select 'Mainboard ->Mainboard Vendor': 'Intel',
> select 'Mainboard -> Mainboard Model': 'Tiger Lake UP3 RVP',
> select 'Debugging -> GDB debugging support': 'y'.
> run 'make'.
>
> What do you think would be the best approach to make the GDB stub work on
> these platforms?
>
> P.S. My bug tracker registration is currently pending an approval, I could
> be able to create a ticket afterwards.
>
> Regards,
> Jan
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