Re: [PATCH] Automatic kernel version module dependencies..

On Sunday 10 February 2008 06:24:37 am Dag-Erling Smørgrav wrote:
"M. Warner Losh" <imp@xxxxxxxxxx> writes:
Dag-Erling_Smørgrav <des@xxxxxx> writes:
...provided they were built from the same config... I think
MUTEX_PROFILING has been fixed, but there may still be cases where
the ABI changes dependening on kernel options.
These are usually well documented. But I can't find any in the
current doc set. Maybe you could point me at options that do this so
we can document them (and maybe add a #warning when compiling with
them)?

Here's one I found: DEBUG_LOCKS changes the size of struct lock, which
changes the size and layout of struct vnode.

Yes, DEBUG_LOCKS, MUTEX_PROFILING (O.B.E), and PAE are the ones I know of. We
could employ a similar strategy for these btw. For example, you could do
this for PAE:

sys/i386/i386/pmap.c:

#ifdef PAE
MODULE_VERSION(pae, 1);
#else
MODULE_VERSION(pae, 0);
#endif

sys/module.h:

#if defined(__i386__)
#ifdef PAE
#define PAE_DEPEND(name) MODULE_DEPEND(name, pae, 1, 1, 1)
#else
#define PAE_DEPEND(name) MODULE_DEPEND(name, pae, 0, 0, 0)
#endif
#else
#define PAE_DEPEND(name) struct __hack
#endif

#define DECLARE_MODULE(name, ...) \
...
PAE_DEPEND(name); \
...

It sucks to have the MD-ness there. Could perhaps have an MI macro like this:

sys/module.h:

#include <machine/module.h>

#ifndef MACHINE_MODULE_DEPEND
#define MACHINE_MODULE_DEPEND struct __hack
#endif


sys/i386/include/module.h:

PAE bits from above but s/PAE_DEPEND/MACHINE_MODULE_DEPEND/. In general we
try to keep the number of such ABI-breaking options to a very bare minimum,
so perhaps one-off hacks in sys/module.h rather than abstracting it is
sufficient.

--
John Baldwin
_______________________________________________
freebsd-arch@xxxxxxxxxxx mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-arch
To unsubscribe, send any mail to "freebsd-arch-unsubscribe@xxxxxxxxxxx"

Relevant Pages