[syslinux] elflink issues

Gene Cumm gene.cumm at gmail.com
Mon Jan 21 07:04:03 PST 2013


On Mon, Jan 21, 2013 at 9:51 AM, Matt Fleming <matt at console-pimps.org> wrote:
> On Sun, 2013-01-20 at 21:22 -0500, Gene Cumm wrote:
>> I noticed several issues when diagnosing why pxechn.c32 didn't work in
>> 5.01-pre3.
>>
>> 1) pxechn.c32, prdhcp.c32 and other modules crash Syslinux and force a
>> reboot by executing an unresolved symbols.  unload_pxe(), dns_resolv()
>> and pxe_call() are the three.  "Error: An undefined symbol was
>> referenced"
>>
>> 2) In past versions, I built a debug build by having "CFLAGS +=
>> -DDEBUG=1" in mk/local.mk but this fails.
>>
>> core/../com32/include/com32.h:144: undefined reference to `__bad_SEG'
>
> You need to also add -DDEBUG_STDIO or -DDEBUG_PORT=0x3f8, etc. See
> mk/devel.mk. This change was introduced below,
>
> commit ff7334a2ce536b7f4b1f6d6f93ff4e285a3bd45a
> Author: H. Peter Anvin <hpa at zytor.com>
> Date:   Thu Jul 19 08:42:32 2012 -0700
>
>     Only compile dprintf/vdprintf if DEBUG_PORT is defined
>
>     We really, really don't want to accidentally spew output to a debug
>     port in production, so make it obligatory to define DEBUG_PORT or
>     DEBUG_STDIO in order for the debugging code to be compiled in.  Since
>     DEBUG_STDIO just turns the debugging code into stdio references, we
>     only need to compile the code for the DEBUG_PORT case.
>
>     Add a commented-out line to mk/devel.mk to make it easier for users.
>
>     Signed-off-by: H. Peter Anvin <hpa at zytor.com>
>     Cc: Matt Fleming <matt.fleming at intel.com>
>
>
> --
> Matt Fleming, Intel Open Source Technology Center

Ahh, thanks for the info.


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