Merge tag 'kbuild-misc-v4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahi...

[linux-2.6-microblaze.git] / samples / livepatch / livepatch-sample.c

diff --git a/samples/livepatch/livepatch-sample.c b/samples/livepatch/livepatch-sample.c
index e34f871..8479522 100644 (file)
--- a/samples/livepatch/livepatch-sample.c
+++ b/samples/livepatch/livepatch-sample.c
@@ -17,6 +17,8 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/livepatch.h>
@@ -69,6 +71,21 @@ static int livepatch_init(void)
 {
        int ret;
 
+       if (!klp_have_reliable_stack() && !patch.immediate) {
+               /*
+                * WARNING: Be very careful when using 'patch.immediate' in
+                * your patches.  It's ok to use it for simple patches like
+                * this, but for more complex patches which change function
+                * semantics, locking semantics, or data structures, it may not
+                * be safe.  Use of this option will also prevent removal of
+                * the patch.
+                *
+                * See Documentation/livepatch/livepatch.txt for more details.
+                */
+               patch.immediate = true;
+               pr_notice("The consistency model isn't supported for your architecture.  Bypassing safety mechanisms and applying the patch immediately.\n");
+       }
+
        ret = klp_register_patch(&patch);
        if (ret)
                return ret;
@@ -82,7 +99,6 @@ static int livepatch_init(void)
 
 static void livepatch_exit(void)
 {
-       WARN_ON(klp_disable_patch(&patch));
        WARN_ON(klp_unregister_patch(&patch));
 }