is there an efficient module_is_builtin() test ?

[Valdis Kl=?utf-8?Q?=c4=93?=tnieks]

On Tue, 09 Mar 2021 12:55:14 -0700, jim.cromie at gmail.com said:

> To use the index, I need  &dyndbg_sites[], and that only works
> for builtin-module's callsites.   For loaded modules, I can/have
> added a pointer to the section into module load_info, giving me
> the base I will need for the ! builtin branch.
>
> I just need a not expensive  is-it-builtin (modref)

One way to sidestep it is to stick in an EXPORT_SYMBOL(dyndbg_sites)
in the .c file you're defining it, and let the module loader do all the heavy
lifting for you. Not sure if some license purist would insist on EXPORT_SYMBOL_GPL
instead - the difference will only matter for out-of-tree non-GPL modules.

An slightly uglier solution is to do something like

#if defined(MODULE)
#define FIND_DEBUG /* code to find via load_info */
#else
#define FIND_DEBUG /* code to load &dyndbg_site directly */
#endif

which you should probably stick into a suitable .h file, and then
stick your newly defined FIND_DEBUG where you need the magic
happen (probably in a .h file as well)