Hi experts,

I built a coreboot image with following steps for tracing coreboot ramstage flow:

1. make menuconfig

---

CONFIG_BOARD_EMULATION_QEMU_X86_Q35=y

CONFIG_GDB_STUB=y

CONFIG_GDB_WAIT=y

---

2. make crossgcc-i386
3. make

Then I start gdb:

4. gdb
5. (gdb) file /mnt/e/work/coreboot/build/cbfs/fallback/ramstage.debug

Reading symbols from /mnt/e/work/coreboot/build/cbfs/fallback/ramstage.debug...

6. (gdb) target remote:1234

Then I start QEMU:

7. qemu-system-i386  --bios build/coreboot.rom -nographic -M q35 -s

--- tty out put as below ---

…

Timestamp - finished loading ramstage: 627985288

BS: postcar times (exec / console): total (unknown) / 80 ms

$S02#b5$S02#b5$S02#b5$S02#b5$S02#b5$S02#b5$S02#b5$S02#b5$S02#b5$S02#

------------

(The “$S02#B5” repeats infinitely. I guess it’s to report a stop event to GDB.)

The GDB successfully connects to coreboot.

“disassemble $eip, +20” works fine.

“n” command doesn’t work.

(gdb) n

Cannot find bounds of current function

What mistake I might make?

Thanks,

Ray