ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/include/soc/qcom/cmd-db.h b/include/soc/qcom/cmd-db.h
new file mode 100644
index 000000000..47a6cab75
--- /dev/null
+++ b/include/soc/qcom/cmd-db.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2024, Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef __QCOM_COMMAND_DB_H__
+#define __QCOM_COMMAND_DB_H__
+
+#include <linux/err.h>
+
+enum cmd_db_hw_type {
+	CMD_DB_HW_INVALID = 0,
+	CMD_DB_HW_MIN     = 3,
+	CMD_DB_HW_ARC     = CMD_DB_HW_MIN,
+	CMD_DB_HW_VRM     = 4,
+	CMD_DB_HW_BCM     = 5,
+	CMD_DB_HW_MAX     = CMD_DB_HW_BCM,
+	CMD_DB_HW_ALL     = 0xff,
+};
+
+#if IS_ENABLED(CONFIG_QCOM_COMMAND_DB)
+u32 cmd_db_read_addr(const char *resource_id);
+
+const void *cmd_db_read_aux_data(const char *resource_id, size_t *len);
+
+bool cmd_db_match_resource_addr(u32 addr1, u32 addr2);
+
+enum cmd_db_hw_type cmd_db_read_slave_id(const char *resource_id);
+
+int cmd_db_ready(void);
+#else
+static inline u32 cmd_db_read_addr(const char *resource_id)
+{ return 0; }
+
+static inline const void *cmd_db_read_aux_data(const char *resource_id, size_t *len)
+{ return ERR_PTR(-ENODEV); }
+
+static inline bool cmd_db_match_resource_addr(u32 addr1, u32 addr2)
+{ return false; }
+
+static inline enum cmd_db_hw_type cmd_db_read_slave_id(const char *resource_id)
+{ return -ENODEV; }
+
+static inline int cmd_db_ready(void)
+{ return -ENODEV; }
+#endif /* CONFIG_QCOM_COMMAND_DB */
+#endif /* __QCOM_COMMAND_DB_H__ */