module: show version information for built-in modules in sysfs
Currently only drivers that are built as modules have their versions
shown in /sys/module/<module_name>/version, but this information might
also be useful for built-in drivers as well. This especially important
for drivers that do not define any parameters - such drivers, if
built-in, are completely invisible from userspace.
This patch changes MODULE_VERSION() macro so that in case when we are
compiling built-in module, version information is stored in a separate
section. Kernel then uses this data to create 'version' sysfs attribute
in the same fashion it creates attributes for module parameters.
Signed-off-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/kernel/params.c b/kernel/params.c
index 08107d1..0da1411 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -719,9 +719,7 @@
params[i].ops->free(params[i].arg);
}
-static void __init kernel_add_sysfs_param(const char *name,
- struct kernel_param *kparam,
- unsigned int name_skip)
+static struct module_kobject * __init locate_module_kobject(const char *name)
{
struct module_kobject *mk;
struct kobject *kobj;
@@ -729,10 +727,7 @@
kobj = kset_find_obj(module_kset, name);
if (kobj) {
- /* We already have one. Remove params so we can add more. */
mk = to_module_kobject(kobj);
- /* We need to remove it before adding parameters. */
- sysfs_remove_group(&mk->kobj, &mk->mp->grp);
} else {
mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
BUG_ON(!mk);
@@ -743,15 +738,36 @@
"%s", name);
if (err) {
kobject_put(&mk->kobj);
- printk(KERN_ERR "Module '%s' failed add to sysfs, "
- "error number %d\n", name, err);
- printk(KERN_ERR "The system will be unstable now.\n");
- return;
+ printk(KERN_ERR
+ "Module '%s' failed add to sysfs, error number %d\n",
+ name, err);
+ printk(KERN_ERR
+ "The system will be unstable now.\n");
+ return NULL;
}
- /* So that exit path is even. */
+
+ /* So that we hold reference in both cases. */
kobject_get(&mk->kobj);
}
+ return mk;
+}
+
+static void __init kernel_add_sysfs_param(const char *name,
+ struct kernel_param *kparam,
+ unsigned int name_skip)
+{
+ struct module_kobject *mk;
+ int err;
+
+ mk = locate_module_kobject(name);
+ if (!mk)
+ return;
+
+ /* We need to remove old parameters before adding more. */
+ if (mk->mp)
+ sysfs_remove_group(&mk->kobj, &mk->mp->grp);
+
/* These should not fail at boot. */
err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
BUG_ON(err);
@@ -796,6 +812,32 @@
}
}
+ssize_t __modver_version_show(struct module_attribute *mattr,
+ struct module *mod, char *buf)
+{
+ struct module_version_attribute *vattr =
+ container_of(mattr, struct module_version_attribute, mattr);
+
+ return sprintf(buf, "%s\n", vattr->version);
+}
+
+extern struct module_version_attribute __start___modver[], __stop___modver[];
+
+static void __init version_sysfs_builtin(void)
+{
+ const struct module_version_attribute *vattr;
+ struct module_kobject *mk;
+ int err;
+
+ for (vattr = __start___modver; vattr < __stop___modver; vattr++) {
+ mk = locate_module_kobject(vattr->module_name);
+ if (mk) {
+ err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
+ kobject_uevent(&mk->kobj, KOBJ_ADD);
+ kobject_put(&mk->kobj);
+ }
+ }
+}
/* module-related sysfs stuff */
@@ -875,6 +917,7 @@
}
module_sysfs_initialized = 1;
+ version_sysfs_builtin();
param_sysfs_builtin();
return 0;