[syslinux] extlinux: missing text on serial output

[H. Peter Anvin]

Ferenc Wagner wrote:
> "H. Peter Anvin" <hpa at zytor.com> writes:
> 
>> H. Peter Anvin wrote:
>>
>>> There isn't all that much I can do about it, other than use an
>>> indirect call here (see patch.)
>>>
>>> I'm slightly hesitant to add this patch to the main code, though, to
>>> support a very old and obviously broken linker.
>> n/m, found an even uglier workaround but which at least doesn't bugger
>> up the object code.  Checked into git.
> 
> :) Thanks, that indeed works for me.  But I really don't expect you to
> maintain "even uglier workarounds" just to please my development
> machine, which I hope to upgrade soon (in Debian terms :).
> 
> Just to wander even farther from the original subject line, the ELF
> format makes symbolic debugging possible.
> 
> $ qemu -fda extlinux.144 -serial stdio -s -S
> $ gdb extlinux.elf
> (gdb) set architecture i8086 
> (gdb) target remote localhost:1234
> 
> gets me pretty far, but I can't get a meaningful backtrace, as if
> GDB didn't recognize the stack correctly.  What do I miss?

Well, gdb wants a very structured stack frame layout, which you're not 
going to get in an assembly program, unfortunately.

I personally use Bochs more than Qemu for debugging, mostly because I 
think its builtin debugger handles segmented memory better than gdb (and 
Qemu has some breakpoint bugs.)

But getting line numbers and symbols is one of the main reasons for 
going to ELF.

	-hpa