Merge tag 'livepatching-for-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching

Pull livepatching updates from Petr Mladek:

 - Allow reloading a livepatched module by clearing livepatch-specific
   relocations in the livepatch module.

   Otherwise, the repeated load would fail on consistency checks.

* tag 'livepatching-for-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
  livepatch,x86: Clear relocation targets on a module removal
  x86/module: remove unused code in __apply_relocate_add

1 files changed, 17 insertions, 0 deletions

diff --git a/include/linux/moduleloader.h b/include/linux/moduleloader.h
index 7b4587a19189..03be088fb439 100644
--- a/include/linux/moduleloader.h
+++ b/include/linux/moduleloader.h
@@ -75,6 +75,23 @@ int apply_relocate_add(Elf_Shdr *sechdrs,
 		       unsigned int symindex,
 		       unsigned int relsec,
 		       struct module *mod);
+#ifdef CONFIG_LIVEPATCH
+/*
+ * Some architectures (namely x86_64 and ppc64) perform sanity checks when
+ * applying relocations.  If a patched module gets unloaded and then later
+ * reloaded (and re-patched), klp re-applies relocations to the replacement
+ * function(s).  Any leftover relocations from the previous loading of the
+ * patched module might trigger the sanity checks.
+ *
+ * To prevent that, when unloading a patched module, clear out any relocations
+ * that might trigger arch-specific sanity checks on a future module reload.
+ */
+void clear_relocate_add(Elf_Shdr *sechdrs,
+		   const char *strtab,
+		   unsigned int symindex,
+		   unsigned int relsec,
+		   struct module *me);
+#endif
 #else
 static inline int apply_relocate_add(Elf_Shdr *sechdrs,
 				     const char *strtab,