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

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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>
This commit is contained in:
Petr Mladek 2019-01-09 13:43:19 +01:00 • committed by Jiri Kosina
parent 1686cc1a31
commit 19514910d0
5 changed files with 19 additions and 17 deletions
Download patch file Download diff file Expand all files Collapse all files

18
kernel/livepatch/patch.c
View file

@ -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);