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, 103 insertions, 0 deletions

diff --git a/drivers/bus/fsl-mc/obj-api.c b/drivers/bus/fsl-mc/obj-api.c
new file mode 100644
index 000000000..06c1dd84e
--- /dev/null
+++ b/drivers/bus/fsl-mc/obj-api.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Copyright 2021 NXP
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/fsl/mc.h>
+
+#include "fsl-mc-private.h"
+
+static int fsl_mc_get_open_cmd_id(const char *type)
+{
+	static const struct {
+		int cmd_id;
+		const char *type;
+	} dev_ids[] = {
+		{ DPRTC_CMDID_OPEN, "dprtc" },
+		{ DPRC_CMDID_OPEN, "dprc" },
+		{ DPNI_CMDID_OPEN, "dpni" },
+		{ DPIO_CMDID_OPEN, "dpio" },
+		{ DPSW_CMDID_OPEN, "dpsw" },
+		{ DPBP_CMDID_OPEN, "dpbp" },
+		{ DPCON_CMDID_OPEN, "dpcon" },
+		{ DPMCP_CMDID_OPEN, "dpmcp" },
+		{ DPMAC_CMDID_OPEN, "dpmac" },
+		{ DPSECI_CMDID_OPEN, "dpseci" },
+		{ DPDMUX_CMDID_OPEN, "dpdmux" },
+		{ DPDCEI_CMDID_OPEN, "dpdcei" },
+		{ DPAIOP_CMDID_OPEN, "dpaiop" },
+		{ DPCI_CMDID_OPEN, "dpci" },
+		{ DPDMAI_CMDID_OPEN, "dpdmai" },
+		{ DPDBG_CMDID_OPEN, "dpdbg" },
+		{ 0, NULL }
+	};
+	int i;
+
+	for (i = 0; dev_ids[i].type; i++)
+		if (!strcmp(dev_ids[i].type, type))
+			return dev_ids[i].cmd_id;
+
+	return -1;
+}
+
+int fsl_mc_obj_open(struct fsl_mc_io *mc_io,
+		    u32 cmd_flags,
+		    int obj_id,
+		    char *obj_type,
+		    u16 *token)
+{
+	struct fsl_mc_command cmd = { 0 };
+	struct fsl_mc_obj_cmd_open *cmd_params;
+	int err = 0;
+	int cmd_id = fsl_mc_get_open_cmd_id(obj_type);
+
+	if (cmd_id == -1)
+		return -ENODEV;
+
+	/* prepare command */
+	cmd.header = mc_encode_cmd_header(cmd_id, cmd_flags, 0);
+	cmd_params = (struct fsl_mc_obj_cmd_open *)cmd.params;
+	cmd_params->obj_id = cpu_to_le32(obj_id);
+
+	/* send command to mc*/
+	err = mc_send_command(mc_io, &cmd);
+	if (err)
+		return err;
+
+	/* retrieve response parameters */
+	*token = mc_cmd_hdr_read_token(&cmd);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(fsl_mc_obj_open);
+
+int fsl_mc_obj_close(struct fsl_mc_io *mc_io,
+		     u32 cmd_flags,
+		     u16 token)
+{
+	struct fsl_mc_command cmd = { 0 };
+
+	/* prepare command */
+	cmd.header = mc_encode_cmd_header(OBJ_CMDID_CLOSE, cmd_flags,
+					  token);
+
+	/* send command to mc*/
+	return mc_send_command(mc_io, &cmd);
+}
+EXPORT_SYMBOL_GPL(fsl_mc_obj_close);
+
+int fsl_mc_obj_reset(struct fsl_mc_io *mc_io,
+		     u32 cmd_flags,
+		     u16 token)
+{
+	struct fsl_mc_command cmd = { 0 };
+
+	/* prepare command */
+	cmd.header = mc_encode_cmd_header(OBJ_CMDID_RESET, cmd_flags,
+					  token);
+
+	/* send command to mc*/
+	return mc_send_command(mc_io, &cmd);
+}
+EXPORT_SYMBOL_GPL(fsl_mc_obj_reset);