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, 297 insertions, 0 deletions

diff --git a/drivers/bus/fsl-mc/mc-sys.c b/drivers/bus/fsl-mc/mc-sys.c
new file mode 100644
index 000000000..31037f418
--- /dev/null
+++ b/drivers/bus/fsl-mc/mc-sys.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Copyright 2013-2016 Freescale Semiconductor Inc.
+ *
+ * I/O services to send MC commands to the MC hardware
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/ioport.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/io-64-nonatomic-hi-lo.h>
+#include <linux/fsl/mc.h>
+
+#include "fsl-mc-private.h"
+
+/*
+ * Timeout in milliseconds to wait for the completion of an MC command
+ */
+#define MC_CMD_COMPLETION_TIMEOUT_MS	15000
+
+/*
+ * usleep_range() min and max values used to throttle down polling
+ * iterations while waiting for MC command completion
+ */
+#define MC_CMD_COMPLETION_POLLING_MIN_SLEEP_USECS    10
+#define MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS    500
+
+static enum mc_cmd_status mc_cmd_hdr_read_status(struct fsl_mc_command *cmd)
+{
+	struct mc_cmd_header *hdr = (struct mc_cmd_header *)&cmd->header;
+
+	return (enum mc_cmd_status)hdr->status;
+}
+
+u16 mc_cmd_hdr_read_cmdid(struct fsl_mc_command *cmd)
+{
+	struct mc_cmd_header *hdr = (struct mc_cmd_header *)&cmd->header;
+	u16 cmd_id = le16_to_cpu(hdr->cmd_id);
+
+	return cmd_id;
+}
+
+static int mc_status_to_error(enum mc_cmd_status status)
+{
+	static const int mc_status_to_error_map[] = {
+		[MC_CMD_STATUS_OK] = 0,
+		[MC_CMD_STATUS_AUTH_ERR] = -EACCES,
+		[MC_CMD_STATUS_NO_PRIVILEGE] = -EPERM,
+		[MC_CMD_STATUS_DMA_ERR] = -EIO,
+		[MC_CMD_STATUS_CONFIG_ERR] = -ENXIO,
+		[MC_CMD_STATUS_TIMEOUT] = -ETIMEDOUT,
+		[MC_CMD_STATUS_NO_RESOURCE] = -ENAVAIL,
+		[MC_CMD_STATUS_NO_MEMORY] = -ENOMEM,
+		[MC_CMD_STATUS_BUSY] = -EBUSY,
+		[MC_CMD_STATUS_UNSUPPORTED_OP] = -ENOTSUPP,
+		[MC_CMD_STATUS_INVALID_STATE] = -ENODEV,
+	};
+
+	if ((u32)status >= ARRAY_SIZE(mc_status_to_error_map))
+		return -EINVAL;
+
+	return mc_status_to_error_map[status];
+}
+
+static const char *mc_status_to_string(enum mc_cmd_status status)
+{
+	static const char *const status_strings[] = {
+		[MC_CMD_STATUS_OK] = "Command completed successfully",
+		[MC_CMD_STATUS_READY] = "Command ready to be processed",
+		[MC_CMD_STATUS_AUTH_ERR] = "Authentication error",
+		[MC_CMD_STATUS_NO_PRIVILEGE] = "No privilege",
+		[MC_CMD_STATUS_DMA_ERR] = "DMA or I/O error",
+		[MC_CMD_STATUS_CONFIG_ERR] = "Configuration error",
+		[MC_CMD_STATUS_TIMEOUT] = "Operation timed out",
+		[MC_CMD_STATUS_NO_RESOURCE] = "No resources",
+		[MC_CMD_STATUS_NO_MEMORY] = "No memory available",
+		[MC_CMD_STATUS_BUSY] = "Device is busy",
+		[MC_CMD_STATUS_UNSUPPORTED_OP] = "Unsupported operation",
+		[MC_CMD_STATUS_INVALID_STATE] = "Invalid state"
+	};
+
+	if ((unsigned int)status >= ARRAY_SIZE(status_strings))
+		return "Unknown MC error";
+
+	return status_strings[status];
+}
+
+/**
+ * mc_write_command - writes a command to a Management Complex (MC) portal
+ *
+ * @portal: pointer to an MC portal
+ * @cmd: pointer to a filled command
+ */
+static inline void mc_write_command(struct fsl_mc_command __iomem *portal,
+				    struct fsl_mc_command *cmd)
+{
+	int i;
+
+	/* copy command parameters into the portal */
+	for (i = 0; i < MC_CMD_NUM_OF_PARAMS; i++)
+		/*
+		 * Data is already in the expected LE byte-order. Do an
+		 * extra LE -> CPU conversion so that the CPU -> LE done in
+		 * the device io write api puts it back in the right order.
+		 */
+		writeq_relaxed(le64_to_cpu(cmd->params[i]), &portal->params[i]);
+
+	/* submit the command by writing the header */
+	writeq(le64_to_cpu(cmd->header), &portal->header);
+}
+
+/**
+ * mc_read_response - reads the response for the last MC command from a
+ * Management Complex (MC) portal
+ *
+ * @portal: pointer to an MC portal
+ * @resp: pointer to command response buffer
+ *
+ * Returns MC_CMD_STATUS_OK on Success; Error code otherwise.
+ */
+static inline enum mc_cmd_status mc_read_response(struct fsl_mc_command __iomem
+						  *portal,
+						  struct fsl_mc_command *resp)
+{
+	int i;
+	enum mc_cmd_status status;
+
+	/* Copy command response header from MC portal: */
+	resp->header = cpu_to_le64(readq_relaxed(&portal->header));
+	status = mc_cmd_hdr_read_status(resp);
+	if (status != MC_CMD_STATUS_OK)
+		return status;
+
+	/* Copy command response data from MC portal: */
+	for (i = 0; i < MC_CMD_NUM_OF_PARAMS; i++)
+		/*
+		 * Data is expected to be in LE byte-order. Do an
+		 * extra CPU -> LE to revert the LE -> CPU done in
+		 * the device io read api.
+		 */
+		resp->params[i] =
+			cpu_to_le64(readq_relaxed(&portal->params[i]));
+
+	return status;
+}
+
+/**
+ * mc_polling_wait_preemptible() - Waits for the completion of an MC
+ *                                 command doing preemptible polling.
+ *                                 uslepp_range() is called between
+ *                                 polling iterations.
+ * @mc_io: MC I/O object to be used
+ * @cmd: command buffer to receive MC response
+ * @mc_status: MC command completion status
+ */
+static int mc_polling_wait_preemptible(struct fsl_mc_io *mc_io,
+				       struct fsl_mc_command *cmd,
+				       enum mc_cmd_status *mc_status)
+{
+	enum mc_cmd_status status;
+	unsigned long jiffies_until_timeout =
+		jiffies + msecs_to_jiffies(MC_CMD_COMPLETION_TIMEOUT_MS);
+
+	/*
+	 * Wait for response from the MC hardware:
+	 */
+	for (;;) {
+		status = mc_read_response(mc_io->portal_virt_addr, cmd);
+		if (status != MC_CMD_STATUS_READY)
+			break;
+
+		/*
+		 * TODO: When MC command completion interrupts are supported
+		 * call wait function here instead of usleep_range()
+		 */
+		usleep_range(MC_CMD_COMPLETION_POLLING_MIN_SLEEP_USECS,
+			     MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS);
+
+		if (time_after_eq(jiffies, jiffies_until_timeout)) {
+			dev_dbg(mc_io->dev,
+				"MC command timed out (portal: %pa, dprc handle: %#x, command: %#x)\n",
+				 &mc_io->portal_phys_addr,
+				 (unsigned int)mc_cmd_hdr_read_token(cmd),
+				 (unsigned int)mc_cmd_hdr_read_cmdid(cmd));
+
+			return -ETIMEDOUT;
+		}
+	}
+
+	*mc_status = status;
+	return 0;
+}
+
+/**
+ * mc_polling_wait_atomic() - Waits for the completion of an MC command
+ *                            doing atomic polling. udelay() is called
+ *                            between polling iterations.
+ * @mc_io: MC I/O object to be used
+ * @cmd: command buffer to receive MC response
+ * @mc_status: MC command completion status
+ */
+static int mc_polling_wait_atomic(struct fsl_mc_io *mc_io,
+				  struct fsl_mc_command *cmd,
+				  enum mc_cmd_status *mc_status)
+{
+	enum mc_cmd_status status;
+	unsigned long timeout_usecs = MC_CMD_COMPLETION_TIMEOUT_MS * 1000;
+
+	BUILD_BUG_ON((MC_CMD_COMPLETION_TIMEOUT_MS * 1000) %
+		     MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS != 0);
+
+	for (;;) {
+		status = mc_read_response(mc_io->portal_virt_addr, cmd);
+		if (status != MC_CMD_STATUS_READY)
+			break;
+
+		udelay(MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS);
+		timeout_usecs -= MC_CMD_COMPLETION_POLLING_MAX_SLEEP_USECS;
+		if (timeout_usecs == 0) {
+			dev_dbg(mc_io->dev,
+				"MC command timed out (portal: %pa, dprc handle: %#x, command: %#x)\n",
+				 &mc_io->portal_phys_addr,
+				 (unsigned int)mc_cmd_hdr_read_token(cmd),
+				 (unsigned int)mc_cmd_hdr_read_cmdid(cmd));
+
+			return -ETIMEDOUT;
+		}
+	}
+
+	*mc_status = status;
+	return 0;
+}
+
+/**
+ * mc_send_command() - Sends a command to the MC device using the given
+ *                     MC I/O object
+ * @mc_io: MC I/O object to be used
+ * @cmd: command to be sent
+ *
+ * Returns '0' on Success; Error code otherwise.
+ */
+int mc_send_command(struct fsl_mc_io *mc_io, struct fsl_mc_command *cmd)
+{
+	int error;
+	enum mc_cmd_status status;
+	unsigned long irq_flags = 0;
+
+	if (in_hardirq() && !(mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL))
+		return -EINVAL;
+
+	if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)
+		raw_spin_lock_irqsave(&mc_io->spinlock, irq_flags);
+	else
+		mutex_lock(&mc_io->mutex);
+
+	/*
+	 * Send command to the MC hardware:
+	 */
+	mc_write_command(mc_io->portal_virt_addr, cmd);
+
+	/*
+	 * Wait for response from the MC hardware:
+	 */
+	if (!(mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL))
+		error = mc_polling_wait_preemptible(mc_io, cmd, &status);
+	else
+		error = mc_polling_wait_atomic(mc_io, cmd, &status);
+
+	if (error < 0)
+		goto common_exit;
+
+	if (status != MC_CMD_STATUS_OK) {
+		dev_dbg(mc_io->dev,
+			"MC command failed: portal: %pa, dprc handle: %#x, command: %#x, status: %s (%#x)\n",
+			 &mc_io->portal_phys_addr,
+			 (unsigned int)mc_cmd_hdr_read_token(cmd),
+			 (unsigned int)mc_cmd_hdr_read_cmdid(cmd),
+			 mc_status_to_string(status),
+			 (unsigned int)status);
+
+		error = mc_status_to_error(status);
+		goto common_exit;
+	}
+
+	error = 0;
+common_exit:
+	if (mc_io->flags & FSL_MC_IO_ATOMIC_CONTEXT_PORTAL)
+		raw_spin_unlock_irqrestore(&mc_io->spinlock, irq_flags);
+	else
+		mutex_unlock(&mc_io->mutex);
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(mc_send_command);