Merge branch 'topic/livepatch' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux into for-4.7/livepatching-ppc64le

Pull livepatching support for ppc64 architecture from Michael Ellerman.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 44 insertions, 4 deletions

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 28c37fa3d3f9..a19f1954f4ac 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -334,6 +334,19 @@ unlock:
 	rcu_read_unlock();
 }
 
+/*
+ * Convert a function address into the appropriate ftrace location.
+ *
+ * Usually this is just the address of the function, but on some architectures
+ * it's more complicated so allow them to provide a custom behaviour.
+ */
+#ifndef klp_get_ftrace_location
+static unsigned long klp_get_ftrace_location(unsigned long faddr)
+{
+	return faddr;
+}
+#endif
+
 static void klp_disable_func(struct klp_func *func)
 {
 	struct klp_ops *ops;
@@ -348,8 +361,14 @@ static void klp_disable_func(struct klp_func *func)
 		return;
 
 	if (list_is_singular(&ops->func_stack)) {
+		unsigned long ftrace_loc;
+
+		ftrace_loc = klp_get_ftrace_location(func->old_addr);
+		if (WARN_ON(!ftrace_loc))
+			return;
+
 		WARN_ON(unregister_ftrace_function(&ops->fops));
-		WARN_ON(ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0));
+		WARN_ON(ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0));
 
 		list_del_rcu(&func->stack_node);
 		list_del(&ops->node);
@@ -374,6 +393,15 @@ static int klp_enable_func(struct klp_func *func)
 
 	ops = klp_find_ops(func->old_addr);
 	if (!ops) {
+		unsigned long ftrace_loc;
+
+		ftrace_loc = klp_get_ftrace_location(func->old_addr);
+		if (!ftrace_loc) {
+			pr_err("failed to find location for function '%s'\n",
+				func->old_name);
+			return -EINVAL;
+		}
+
 		ops = kzalloc(sizeof(*ops), GFP_KERNEL);
 		if (!ops)
 			return -ENOMEM;
@@ -388,7 +416,7 @@ static int klp_enable_func(struct klp_func *func)
 		INIT_LIST_HEAD(&ops->func_stack);
 		list_add_rcu(&func->stack_node, &ops->func_stack);
 
-		ret = ftrace_set_filter_ip(&ops->fops, func->old_addr, 0, 0);
+		ret = ftrace_set_filter_ip(&ops->fops, ftrace_loc, 0, 0);
 		if (ret) {
 			pr_err("failed to set ftrace filter for function '%s' (%d)\n",
 			       func->old_name, ret);
@@ -399,7 +427,7 @@ static int klp_enable_func(struct klp_func *func)
 		if (ret) {
 			pr_err("failed to register ftrace handler for function '%s' (%d)\n",
 			       func->old_name, ret);
-			ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0);
+			ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0);
 			goto err;
 		}
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 57a6eea84694..f4e6aae6ebe7 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1533,7 +1533,19 @@ static int ftrace_cmp_recs(const void *a, const void *b)
 	return 0;
 }
 
-static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
+/**
+ * ftrace_location_range - return the first address of a traced location
+ *	if it touches the given ip range
+ * @start: start of range to search.
+ * @end: end of range to search (inclusive). @end points to the last byte
+ *	to check.
+ *
+ * Returns rec->ip if the related ftrace location is a least partly within
+ * the given address range. That is, the first address of the instruction
+ * that is either a NOP or call to the function tracer. It checks the ftrace
+ * internal tables to determine if the address belongs or not.
+ */
+unsigned long ftrace_location_range(unsigned long start, unsigned long end)
 {
 	struct ftrace_page *pg;
 	struct dyn_ftrace *rec;