kallsyms, bpf: Move find_kallsyms_symbol_value out of internal header

Moving find_kallsyms_symbol_value from kernel/module/internal.h to
include/linux/module.h. The reason is that internal.h is not prepared to
be included when CONFIG_MODULES=n. find_kallsyms_symbol_value is used by
kernel/bpf/verifier.c and including internal.h from it (without modules)
leads into a compilation error:

  In file included from ../include/linux/container_of.h:5,
                   from ../include/linux/list.h:5,
                   from ../include/linux/timer.h:5,
                   from ../include/linux/workqueue.h:9,
                   from ../include/linux/bpf.h:10,
                   from ../include/linux/bpf-cgroup.h:5,
                   from ../kernel/bpf/verifier.c:7:
  ../kernel/bpf/../module/internal.h: In function 'mod_find':
  ../include/linux/container_of.h:20:54: error: invalid use of undefined type 'struct module'
     20 |         static_assert(__same_type(*(ptr), ((type *)0)->member) ||       \
        |                                                      ^~
  [...]

This patch fixes the above error.

Fixes: 31bf1db ("bpf: Fix attaching fentry/fexit/fmod_ret/lsm to modules")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/oe-kbuild-all/202303161404.OrmfCy09-lkp@intel.com/
Link: https://lore.kernel.org/bpf/20230317095601.386738-1-vmalik@redhat.com

include/linux/module.h

@@ -616,6 +616,8 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 /* Look for this name: can be of form module:name. */
 unsigned long module_kallsyms_lookup_name(const char *name);
 
+unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name);
+
 extern void __noreturn __module_put_and_kthread_exit(struct module *mod,
 			long code);
 #define module_put_and_kthread_exit(code) __module_put_and_kthread_exit(THIS_MODULE, code)
@@ -796,6 +798,12 @@ static inline unsigned long module_kallsyms_lookup_name(const char *name)
 	return 0;
 }
 
+static inline unsigned long find_kallsyms_symbol_value(struct module *mod,
+						       const char *name)
+{
+	return 0;
+}
+
 static inline int register_module_notifier(struct notifier_block *nb)
 {
 	/* no events will happen anyway, so this can always succeed */

kernel/bpf/verifier.c

@@ -24,7 +24,7 @@
 #include <linux/bpf_lsm.h>
 #include <linux/btf_ids.h>
 #include <linux/poison.h>
-#include "../module/internal.h"
+#include <linux/module.h>
 
 #include "disasm.h"
 

kernel/module/internal.h

@@ -246,7 +246,6 @@ static inline void kmemleak_load_module(const struct module *mod,
 void init_build_id(struct module *mod, const struct load_info *info);
 void layout_symtab(struct module *mod, struct load_info *info);
 void add_kallsyms(struct module *mod, const struct load_info *info);
-unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name);
 
 static inline bool sect_empty(const Elf_Shdr *sect)
 {
@@ -256,11 +255,6 @@ static inline bool sect_empty(const Elf_Shdr *sect)
 static inline void init_build_id(struct module *mod, const struct load_info *info) { }
 static inline void layout_symtab(struct module *mod, struct load_info *info) { }
 static inline void add_kallsyms(struct module *mod, const struct load_info *info) { }
-static inline unsigned long find_kallsyms_symbol_value(struct module *mod,
-						       const char *name)
-{
-	return 0;
-}
 #endif /* CONFIG_KALLSYMS */
 
 #ifdef CONFIG_SYSFS