module: Overwrite st_size instead of st_info

st_info is currently overwritten after relocation and used to store the
elf_type().  However, we're going to need it fix kallsyms on ARM's
Thumb-2 kernels, so preserve st_info and overwrite the st_size field
instead.  st_size is neither used by the module core nor by any
architecture.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

kernel/module.c

@@ -2684,7 +2684,7 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
 
 	/* Set types up while we still have access to sections. */
 	for (i = 0; i < mod->kallsyms->num_symtab; i++)
-		mod->kallsyms->symtab[i].st_info
+		mod->kallsyms->symtab[i].st_size
 			= elf_type(&mod->kallsyms->symtab[i], info);
 
 	/* Now populate the cut down core kallsyms for after init. */
@@ -4070,7 +4070,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 		kallsyms = rcu_dereference_sched(mod->kallsyms);
 		if (symnum < kallsyms->num_symtab) {
 			*value = kallsyms->symtab[symnum].st_value;
-			*type = kallsyms->symtab[symnum].st_info;
+			*type = kallsyms->symtab[symnum].st_size;
 			strlcpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN);
 			strlcpy(module_name, mod->name, MODULE_NAME_LEN);
 			*exported = is_exported(name, *value, mod);