building world with debugging symbols [broken?]

[Sergey V. Dyatko]

On Tue, 22 Jun 2010 14:07:21 -0700
Ted Faber <faber at isi.edu> wrote:

> On Tue, Jun 22, 2010 at 04:39:17PM -0400, Ryan Stone wrote:
> > I saw similar behaviour a couple of years ago when I switched from
> > using gcc 4.0.2 to gcc 4.3.0 to compile some out-of-tree KLD
> > modules. The problem ended up being a change in the linker script
> > used by GNU ld for linking kernel modules.  It used to always put
> > some magic symbols used by the linker to implement things like
> > sysinits into the module.  It was changed to only provide those
> > symbols, which apparently means that the linker would discard those
> > symbols if nothing referenced them(and nothing did reference
> > them).  I had to work around it by adding the following to my link
> > line:
> > 
> > -u __start_set_sysinit_set -u __start_set_sysuninit_set \
> > -u __start_set_sysctl_set -u __start_set_modmetadata_set \
> > -u __stop_set_sysinit_set -u __stop_set_sysuninit_set \
> > -u __stop_set_sysctl_set -u __stop_set_modmetadata_set
> 
> HPS:
> 
> I added those lines to the LDFLAGS in Makefile.kmod in the cuse4bsd
> port made the module and the result loads and creates the /dev/cuse
> file.
> 
works fine for me too. 
pwcview and mplayer (mplayer tv:// -tv
driver=v4l[12]:width=640:height=480:device=/dev/video0)

but, unfortunately skype doesn't work:((

> Here's a diff relative to
> /usr/ports/multimedia/cuse4bsd-kmod/work/cuse4bsd-kmod-0.1.11 just so
> it's clear what I did.
> 
> 
> --- Makefile.kmod.orig  2010-02-11 03:28:02.000000000 -0800
> +++ Makefile.kmod       2010-06-22 14:02:52.000000000 -0700
> @@ -30,4 +30,10 @@
>  KMOD=  cuse4bsd
>  SRCS=  cuse4bsd_kmod.c device_if.h bus_if.h vnode_if.h
>  
> +LDFLAGS += -u __start_set_sysinit_set -u __start_set_sysuninit_set \
> + -u __start_set_sysctl_set -u __start_set_modmetadata_set \
> + -u __stop_set_sysinit_set -u __stop_set_sysuninit_set \
> + -u __stop_set_sysctl_set -u __stop_set_modmetadata_set
> +
> +
>  .include <bsd.kmod.mk>
> 
> Running nm -o on the two modules, the difference seems to be that the
> -u results in some additional absolute symbols being defined:
> 
> Bad module:
> $ nm -o /boot/modules/cuse4bsd.ko| grep sys
> /boot/modules/cuse4bsd.ko:0000275c r
> __set_sysinit_set_sym_cuse_kern_init_sys_init
> /boot/modules/cuse4bsd.ko:00002758 r
> __set_sysuninit_set_sym_cuse_kern_uninit_sys_uninit /boot/modules/cuse4bsd.ko:00003194
> d cuse_kern_init_sys_init /boot/modules/cuse4bsd.ko:00003184 d
> cuse_kern_uninit_sys_uninit
> 
> Good module:
> 
> $ nm -o ./cuse4bsd.ko  | grep sys
> ./cuse4bsd.ko:000028cc r __set_sysinit_set_sym_cuse_kern_init_sys_init
> ./cuse4bsd.ko:000028c8 r
> __set_sysuninit_set_sym_cuse_kern_uninit_sys_uninit ./cuse4bsd.ko:
> U __start_set_sysctl_set ./cuse4bsd.ko:000028cc A
> __start_set_sysinit_set ./cuse4bsd.ko:000028c8 A
> __start_set_sysuninit_set ./cuse4bsd.ko:         U
> __stop_set_sysctl_set ./cuse4bsd.ko:000028d0 A __stop_set_sysinit_set
> ./cuse4bsd.ko:000028cc A __stop_set_sysuninit_set
> ./cuse4bsd.ko:00003194 d cuse_kern_init_sys_init
> ./cuse4bsd.ko:00003184 d cuse_kern_uninit_sys_uninit
> 
> 



-- 
wbr, tiger