[SeaBIOS] [BUG?] Doesn't retrieve control after coreboot payload return

[Antonello Dettori]

Hi everyone.

I'm currently working on coreboot but I stumbled on a strange SeaBIOS 
behaviour.
After executing a payload and returning control to the caller SeaBIOS 
crashes.

The problem is currently solved by rebooting before the payload returns 
but doing so also makes chaining multiple payloads impossible so I'm 
trying to look into a solution.

I tried to increment the debug level to 8 to get more information and 
the attached log is what I got.
I also attached a build of coreboot with this problem if someone wants 
to try it in QEMU.

I'm not terribly knowledgeable about SeaBIOS so I'm a bit lost.

Could anyone point me where the problem could be originating from?

Thanks in advance,

Antonello Dettori

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General Protection Fault Exception
Error code: 0x20 - descriptor 0x4 in the GDT, internal to the CPU
EIP:    0x000fe6a9
CS:     0x0010
EFLAGS: 0x00000002
EAX:    0x00006fca
ECX:    0x00000020
EDX:    0x000077c0
EBX:    0x00000000
ESP:    0x00006fb0
EBP:    0x00100000
ESI:    0x00009458
EDI:    0x00000000
DS:     0x0018
ES:     0x0018
SS:     0x0018
FS:     0x0018
GS:     0x0018
Dumping stack:
0x71a0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x7180: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x7160: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x7140: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x7120: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x7100: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x70e0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x70c0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x70a0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x7080: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x7060: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x7040: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x7020: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x7000: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
0x6fe0: 00000000 00000000 e9840000 0200f000 00000000 00000000 00000000 00000000 
0x6fc0: 00000000 ffe0f6a8 0000fc82 00000000 00000000 00000000 00000000 00000000 
0x6fa0: 00000020 000fe6a9 00000010 00000002 00006fb4 00006fb4 001626b0 000f4724 

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