livepatch: Change unsigned long old_addr -> void *old_func in struct klp_func

The address of the to be patched function and new function is stored
in struct klp_func as:

	void *new_func;
	unsigned long old_addr;

The different naming scheme and type are derived from the way
the addresses are set. @old_addr is assigned at runtime using
kallsyms-based search. @new_func is statically initialized,
for example:

  static struct klp_func funcs[] = {
	{
		.old_name = "cmdline_proc_show",
		.new_func = livepatch_cmdline_proc_show,
	}, { }
  };

This patch changes unsigned long old_addr -> void *old_func. It removes
some confusion when these address are later used in the code. It is
motivated by a followup patch that adds special NOP struct klp_func
where we want to assign func->new_func = func->old_addr respectively
func->new_func = func->old_func.

This patch does not modify the existing behavior.

Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Alice Ferrazzi <alice.ferrazzi@gmail.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 10 insertions, 8 deletions

diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c
index 7702cb4064fc..825022d70912 100644
--- a/kernel/livepatch/patch.c
+++ b/kernel/livepatch/patch.c
@@ -34,7 +34,7 @@
 
 static LIST_HEAD(klp_ops);
 
-struct klp_ops *klp_find_ops(unsigned long old_addr)
+struct klp_ops *klp_find_ops(void *old_func)
 {
         struct klp_ops *ops;
         struct klp_func *func;
@@ -42,7 +42,7 @@ struct klp_ops *klp_find_ops(unsigned long old_addr)
         list_for_each_entry(ops, &klp_ops, node) {
                 func = list_first_entry(&ops->func_stack, struct klp_func,
                                         stack_node);
-                if (func->old_addr == old_addr)
+                if (func->old_func == old_func)
                         return ops;
         }
 
@@ -142,17 +142,18 @@ static void klp_unpatch_func(struct klp_func *func)
 
         if (WARN_ON(!func->patched))
                 return;
-        if (WARN_ON(!func->old_addr))
+        if (WARN_ON(!func->old_func))
                 return;
 
-        ops = klp_find_ops(func->old_addr);
+        ops = klp_find_ops(func->old_func);
         if (WARN_ON(!ops))
                 return;
 
         if (list_is_singular(&ops->func_stack)) {
                 unsigned long ftrace_loc;
 
-                ftrace_loc = klp_get_ftrace_location(func->old_addr);
+                ftrace_loc =
+                        klp_get_ftrace_location((unsigned long)func->old_func);
                 if (WARN_ON(!ftrace_loc))
                         return;
 
@@ -174,17 +175,18 @@ static int klp_patch_func(struct klp_func *func)
         struct klp_ops *ops;
         int ret;
 
-        if (WARN_ON(!func->old_addr))
+        if (WARN_ON(!func->old_func))
                 return -EINVAL;
 
         if (WARN_ON(func->patched))
                 return -EINVAL;
 
-        ops = klp_find_ops(func->old_addr);
+        ops = klp_find_ops(func->old_func);
         if (!ops) {
                 unsigned long ftrace_loc;
 
-                ftrace_loc = klp_get_ftrace_location(func->old_addr);
+                ftrace_loc =
+                        klp_get_ftrace_location((unsigned long)func->old_func);
                 if (!ftrace_loc) {
                         pr_err("failed to find location for function '%s'\n",
                                 func->old_name);