Questions regarding 'struct modstat'

[Paul Goyette <paul%vps1.whooppee.com@localhost>]

In sys/sys/module.h, we have the following definition of the 'struct 
modstat' structure, (used by modctl(MODCTL_STAT, ...) to return kernel
data to userland):

...
/*
 * This structure intentionally has the same layout for 32 and 64
 * bit builds.
 */
typedef struct modstat {
        char            ms_name[MAXMODNAME];
        char            ms_required[MAXMODNAME * MAXMODDEPS];
        uint64_t        ms_addr;
        modsrc_t        ms_source;
        modclass_t      ms_class;
        u_int           ms_size;
        u_int           ms_refcnt;
        u_int           ms_reserved[4];
} modstat_t;
...

I have some questions:

1. Despite the comment, aren't the u_int fields of different sizes in
   32- vs 64-bit builds?  The comment seems to be somewhat misleading.

2. Is there any assurance that the module's load address (in ms_addr)
   can fit in a uint64_t?

3. If I wanted to add another address field (ms_modaddr for the address
   of the module's 'struct module'), would it be better to

	a) insert a new uint64_t in the middle of this structure,
	   after the current ms_addr field,

	b) insert a new uint64_t in the middle of this structure,
	   immediately before the ms_reserved[] array,

	c) append a new uint64_t at the end of this structure, or

	d) replace some number of the ms_reserved[] array with a
	   new uint64_t structure (and how many to replace?)




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