[PATCH 6.18.y 2/4] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS

[Sasha Levin <sashal@kernel.org>]

From: Menglong Dong <menglong8.dong@gmail.com>

[ Upstream commit cd06078a38aaedfebbf8fa0c009da0f99f4473fb ]

For now, we will use ftrace for the fprobe if fp->exit_handler not exists
and CONFIG_DYNAMIC_FTRACE_WITH_REGS is enabled.

However, CONFIG_DYNAMIC_FTRACE_WITH_REGS is not supported by some arch,
such as arm. What we need in the fprobe is the function arguments, so we
can use ftrace for fprobe if CONFIG_DYNAMIC_FTRACE_WITH_ARGS is enabled.

Therefore, use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_REGS or
CONFIG_DYNAMIC_FTRACE_WITH_ARGS enabled.

Link: https://lore.kernel.org/all/20251103063434.47388-1-dongml2@chinatelecom.cn/

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Stable-dep-of: 0ac0058a74ac ("tracing/fprobe: Check the same type fprobe on table as the unregistered one")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/trace/fprobe.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 51003d85933d9..574f2886cc9e3 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -45,6 +45,7 @@
 static struct hlist_head fprobe_table[FPROBE_TABLE_SIZE];
 static struct rhltable fprobe_ip_table;
 static DEFINE_MUTEX(fprobe_mutex);
+static struct fgraph_ops fprobe_graph_ops;
 
 static u32 fprobe_node_hashfn(const void *data, u32 len, u32 seed)
 {
@@ -259,7 +260,7 @@ static inline int __fprobe_kprobe_handler(unsigned long ip, unsigned long parent
 	return ret;
 }
 
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+#if defined(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) || defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS)
 /* ftrace_ops callback, this processes fprobes which have only entry_handler. */
 static void fprobe_ftrace_entry(unsigned long ip, unsigned long parent_ip,
 	struct ftrace_ops *ops, struct ftrace_regs *fregs)
@@ -300,7 +301,7 @@ NOKPROBE_SYMBOL(fprobe_ftrace_entry);
 
 static struct ftrace_ops fprobe_ftrace_ops = {
 	.func	= fprobe_ftrace_entry,
-	.flags	= FTRACE_OPS_FL_SAVE_REGS,
+	.flags	= FTRACE_OPS_FL_SAVE_ARGS,
 };
 static int fprobe_ftrace_active;
 
@@ -341,6 +342,15 @@ static bool fprobe_is_ftrace(struct fprobe *fp)
 {
 	return !fp->exit_handler;
 }
+
+#ifdef CONFIG_MODULES
+static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove,
+			   int reset)
+{
+	ftrace_set_filter_ips(&fprobe_graph_ops.ops, ips, cnt, remove, reset);
+	ftrace_set_filter_ips(&fprobe_ftrace_ops, ips, cnt, remove, reset);
+}
+#endif
 #else
 static int fprobe_ftrace_add_ips(unsigned long *addrs, int num)
 {
@@ -355,7 +365,15 @@ static bool fprobe_is_ftrace(struct fprobe *fp)
 {
 	return false;
 }
+
+#ifdef CONFIG_MODULES
+static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove,
+			   int reset)
+{
+	ftrace_set_filter_ips(&fprobe_graph_ops.ops, ips, cnt, remove, reset);
+}
 #endif
+#endif /* !CONFIG_DYNAMIC_FTRACE_WITH_ARGS && !CONFIG_DYNAMIC_FTRACE_WITH_REGS */
 
 /* fgraph_ops callback, this processes fprobes which have exit_handler. */
 static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops *gops,
@@ -601,14 +619,8 @@ static int fprobe_module_callback(struct notifier_block *nb,
 	} while (node == ERR_PTR(-EAGAIN));
 	rhashtable_walk_exit(&iter);
 
-	if (alist.index > 0) {
-		ftrace_set_filter_ips(&fprobe_graph_ops.ops,
-				      alist.addrs, alist.index, 1, 0);
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
-		ftrace_set_filter_ips(&fprobe_ftrace_ops,
-				      alist.addrs, alist.index, 1, 0);
-#endif
-	}
+	if (alist.index > 0)
+		fprobe_set_ips(alist.addrs, alist.index, 1, 0);
 	mutex_unlock(&fprobe_mutex);
 
 	kfree(alist.addrs);
-- 
2.53.0