[coreboot] (GSoC__SCSI boot)GSOC Midterm survey and new problem(Vendor ID mismatch)

Zhang Rui zrfail at gmail.com
Mon Jul 14 17:21:47 CEST 2008

2008/7/14, Kevin O'Connor <kevin at koconnor.net>:
> Right - seabios needs to be using its stack in order to call 16bit
> functions.  You probably need to save and restore the stack.
> Completely untested, but something like:
>  movl %esp, %esi
>  movl $BUILD_STACK_ADDR, %esp
>  ljmp 0x10, $1f
> 1:
>  calll post_coreboot
>  movl %esi, %esp
>  retl

I used this:
    "movl %esp, %esi\n"
    "movl $" __stringify(BUILD_STACK_ADDR) ", %esp\n"
    "ljmp $0x10, $post_coreboot\n"

and added this at the end of post_coreboot() function:
	"movl %esi, %esp\n"

Then it can return to coreboot correctly. Till the payload(I used no
payload here)

But pci_dev_init() is executed more than one time so vga is
initialized more than one time in SeaBIOS. A flag variable would be
used to run SeaBIOS only once.

> However, note that the above wont save/restore the idt/gdt.  And
> again, I'm not sure if coreboot puts its stack/idt/gdt somewhere where
> seabios may overwrite it.

I am supprised that it just run correctly when return address is set.
I supposed to restore the gdt. Maybe the gdt of SeaBIOS and coreboot
are the same.

And I want to know where will SeaBIOS write in the memory. Such as the
range of bda and ebda?

I think it is time to int SCSI controller, and set the int 13 for it.

Best regards.
Zhang Rui

More information about the coreboot mailing list