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, 54 insertions, 0 deletions

diff --git a/include/soc/microchip/mpfs.h b/include/soc/microchip/mpfs.h
new file mode 100644
index 000000000..ec04c98a8
--- /dev/null
+++ b/include/soc/microchip/mpfs.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *
+ * Microchip PolarFire SoC (MPFS)
+ *
+ * Copyright (c) 2020 Microchip Corporation. All rights reserved.
+ *
+ * Author: Conor Dooley <conor.dooley@microchip.com>
+ *
+ */
+
+#ifndef __SOC_MPFS_H__
+#define __SOC_MPFS_H__
+
+#include <linux/types.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+struct mpfs_sys_controller;
+
+struct mpfs_mss_msg {
+	u8 cmd_opcode;
+	u16 cmd_data_size;
+	struct mpfs_mss_response *response;
+	u8 *cmd_data;
+	u16 mbox_offset;
+	u16 resp_offset;
+};
+
+struct mpfs_mss_response {
+	u32 resp_status;
+	u32 *resp_msg;
+	u16 resp_size;
+};
+
+#if IS_ENABLED(CONFIG_POLARFIRE_SOC_SYS_CTRL)
+
+int mpfs_blocking_transaction(struct mpfs_sys_controller *mpfs_client, struct mpfs_mss_msg *msg);
+
+struct mpfs_sys_controller *mpfs_sys_controller_get(struct device *dev);
+
+struct mtd_info *mpfs_sys_controller_get_flash(struct mpfs_sys_controller *mpfs_client);
+
+#endif /* if IS_ENABLED(CONFIG_POLARFIRE_SOC_SYS_CTRL) */
+
+#if IS_ENABLED(CONFIG_MCHP_CLK_MPFS)
+#if IS_ENABLED(CONFIG_RESET_POLARFIRE_SOC)
+int mpfs_reset_controller_register(struct device *clk_dev, struct regmap *map);
+#else
+static inline int mpfs_reset_controller_register(struct device *clk_dev, void __iomem *base) { return 0; }
+#endif /* if IS_ENABLED(CONFIG_RESET_POLARFIRE_SOC) */
+#endif /* if IS_ENABLED(CONFIG_MCHP_CLK_MPFS) */
+
+#endif /* __SOC_MPFS_H__ */