Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 395 insertions, 0 deletions

diff --git a/drivers/mailbox/axiado-mailbox.c b/drivers/mailbox/axiado-mailbox.c
new file mode 100644
index 000000000..3a3cf7421
--- /dev/null
+++ b/drivers/mailbox/axiado-mailbox.c
@@ -0,0 +1,395 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2021-2026 Axiado Corporation (or its affiliates).
+ */
+
+#include <linux/atomic.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/bitfield.h>
+#include <linux/debugfs.h>
+#include <linux/iopoll.h>
+#include <linux/mailbox_controller.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/unaligned.h>
+
+#define AXIADO_MBOX_TX_CHANS		8	/* 0-7 */
+#define AXIADO_MBOX_RX_CHANS		8	/* 8-15 */
+#define AXIADO_MBOX_CHAN_STRIDE	0x4
+#define AXIADO_MBOX_TX_REG_STRIDE	0x40
+#define AXIADO_MBOX_RX_REG_STRIDE	0x30
+#define AXIADO_MBOX_RX_POLL_US		10
+#define AXIADO_MBOX_RX_TIMEOUT_US	1000
+
+/* Mailbox CSR bit definitions */
+#define AXIADO_MBOX_CSR_EMPTY		BIT(0) /* 1 = FIFO empty; 0 = data available */
+#define AXIADO_MBOX_CSR_OVERFLOW	BIT(2) /* write 1 to clear (W1C) */
+#define AXIADO_MBOX_CSR_UNDERFLOW	BIT(3) /* write 1 to clear (W1C) */
+#define AXIADO_MBOX_CSR_FLUSH		BIT(4) /* W1TRG flush; startup/shutdown */
+#define AXIADO_MBOX_CSR_LEVEL		GENMASK(11, 5)
+
+#define AXIADO_MBOX_CSR_ERRORS		(AXIADO_MBOX_CSR_OVERFLOW | \
+					 AXIADO_MBOX_CSR_UNDERFLOW)
+
+struct axiado_mbox_data {
+	u8 num_chans;
+	u16 msg_size;
+};
+
+struct axiado_channel_data {
+	void __iomem *mbox_reg;
+	void __iomem *csr_reg;
+	void *rx_buffer;
+	u8 channel_num;
+	int irq;
+	struct mbox_chan *chan;
+	bool active;
+	atomic_t fifo_errors;
+};
+
+/* mailbox side */
+struct axiado_mbox {
+	struct mbox_controller mbox;
+	const struct axiado_mbox_data *drv_data;
+	void __iomem *tx_base;
+	void __iomem *rx_base;
+	struct dentry *debugfs_dir;
+};
+
+/*
+ * Checks OVERFLOW/UNDERFLOW, logs and W1C-clears them if set. Shared by the
+ * TX and RX paths; RX additionally flushes the FIFO afterwards to resync
+ * framing, which TX must not do since it could discard data the peer has
+ * not read yet.
+ */
+static bool axiado_mbox_clear_fifo_errors(struct axiado_channel_data *priv)
+{
+	struct device *dev = priv->chan->mbox->dev;
+	u32 errors;
+
+	errors = readl(priv->csr_reg) & AXIADO_MBOX_CSR_ERRORS;
+	if (!errors)
+		return false;
+
+	writel(errors, priv->csr_reg);
+	atomic_inc(&priv->fifo_errors);
+
+	dev_warn_ratelimited(dev, "Channel %u FIFO error: %#x\n",
+			     priv->channel_num, errors);
+
+	return true;
+}
+
+static int axiado_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+	struct axiado_mbox *mb = dev_get_drvdata(chan->mbox->dev);
+	struct axiado_channel_data *priv = chan->con_priv;
+	unsigned int idx = priv->channel_num;
+	u8 tail[sizeof(u32)] = { 0 };
+	const u8 *buf = data;
+	unsigned int tail_len;
+	unsigned int offset;
+	u32 msg_len;
+
+	if (!data)
+		return -EINVAL;
+
+	/*
+	 * The Axiado mailbox message ABI stores the total message length,
+	 * including this length word, as a little-endian byte count in the
+	 * first word of every message.
+	 */
+	msg_len = get_unaligned_le32(data);
+	if (msg_len < sizeof(u32) || msg_len > mb->drv_data->msg_size)
+		return -EINVAL;
+
+	/* Only touch the hardware after validating the message. */
+	axiado_mbox_clear_fifo_errors(priv);
+
+	if (!(readl(priv->csr_reg) & AXIADO_MBOX_CSR_EMPTY)) {
+		dev_warn_ratelimited(mb->mbox.dev, "Channel %u is busy\n", idx);
+		return -EBUSY;
+	}
+
+	for (offset = 0; offset + sizeof(u32) <= msg_len;
+	     offset += sizeof(u32))
+		writel(get_unaligned_le32(buf + offset), priv->mbox_reg);
+
+	tail_len = msg_len - offset;
+	if (tail_len) {
+		memcpy(tail, buf + offset, tail_len);
+		writel(get_unaligned_le32(tail), priv->mbox_reg);
+	}
+
+	dev_dbg(mb->mbox.dev, "%s: Ch-%u sent\n", __func__, idx);
+
+	return 0;
+}
+
+static irqreturn_t axiado_rx_thread(int irq, void *dev_id)
+{
+	struct axiado_channel_data *priv = dev_id;
+	struct mbox_chan *chan = priv->chan;
+	struct axiado_mbox *mb = dev_get_drvdata(chan->mbox->dev);
+	u8 *buf = priv->rx_buffer;
+	unsigned int num_words;
+	unsigned int remaining;
+	unsigned int i;
+	u32 msg_len;
+	u32 word;
+	u32 csr;
+	int ret;
+
+	/*
+	 * Clear and log/count any pending errors, but don't discard data
+	 * on their account alone: a rejected overflow write doesn't
+	 * corrupt what was already safely queued ahead of it, so let the
+	 * length-based read below decide whether what's here is usable.
+	 */
+	axiado_mbox_clear_fifo_errors(priv);
+
+	csr = readl(priv->csr_reg);
+	if (csr & AXIADO_MBOX_CSR_EMPTY)
+		return IRQ_NONE;
+
+	/*
+	 * The first word contains the total message length in bytes,
+	 * including the length word itself.
+	 */
+	word = readl(priv->mbox_reg);
+	msg_len = word;
+	put_unaligned_le32(word, buf);
+
+	if (msg_len < sizeof(u32) || msg_len > mb->drv_data->msg_size)
+		goto invalid_message;
+
+	num_words = DIV_ROUND_UP(msg_len, sizeof(u32));
+	remaining = num_words - 1;
+
+	/*
+	 * The not-empty interrupt may occur as soon as the first DW enters
+	 * the FIFO. Wait until all remaining DWs of this message arrive.
+	 */
+	if (remaining) {
+		ret = readl_poll_timeout(priv->csr_reg, csr,
+					 (csr & AXIADO_MBOX_CSR_ERRORS) ||
+					  FIELD_GET(AXIADO_MBOX_CSR_LEVEL, csr) >=
+					  remaining,
+					  AXIADO_MBOX_RX_POLL_US,
+					  AXIADO_MBOX_RX_TIMEOUT_US);
+		if (ret)
+			goto incomplete_message;
+
+		axiado_mbox_clear_fifo_errors(priv);
+	}
+
+	for (i = 1; i < num_words; i++) {
+		word = readl(priv->mbox_reg);
+		put_unaligned_le32(word, buf + i * sizeof(u32));
+	}
+
+	axiado_mbox_clear_fifo_errors(priv);
+
+	if (READ_ONCE(priv->active))
+		mbox_chan_received_data(chan, priv->rx_buffer);
+
+	return IRQ_HANDLED;
+
+incomplete_message:
+	dev_warn_ratelimited(chan->mbox->dev,
+			     "Channel %u received an incomplete message\n",
+			     priv->channel_num);
+
+invalid_message:
+	writel(AXIADO_MBOX_CSR_FLUSH, priv->csr_reg);
+
+	return IRQ_HANDLED;
+}
+
+static int axiado_mbox_startup(struct mbox_chan *chan)
+{
+	struct axiado_channel_data *priv = chan->con_priv;
+
+	/*
+	 * Only flush on a genuine error. A blind flush here would discard
+	 * a message the peer legitimately sent before this side started
+	 * up (e.g. during normal boot sequencing), which is not corrupt
+	 * and does not need resyncing.
+	 */
+	if (axiado_mbox_clear_fifo_errors(priv))
+		writel(AXIADO_MBOX_CSR_FLUSH, priv->csr_reg);
+
+	WRITE_ONCE(priv->active, true);
+
+	if (priv->channel_num >= AXIADO_MBOX_TX_CHANS)
+		enable_irq(priv->irq);
+
+	return 0;
+}
+
+static void axiado_mbox_shutdown(struct mbox_chan *chan)
+{
+	struct axiado_channel_data *priv = chan->con_priv;
+
+	WRITE_ONCE(priv->active, false);
+
+	if (priv->channel_num >= AXIADO_MBOX_TX_CHANS)
+		disable_irq(priv->irq);
+
+	if (axiado_mbox_clear_fifo_errors(priv))
+		writel(AXIADO_MBOX_CSR_FLUSH, priv->csr_reg);
+}
+
+static bool axiado_mbox_last_tx_done(struct mbox_chan *chan)
+{
+	struct axiado_channel_data *priv = chan->con_priv;
+
+	return !!(readl(priv->csr_reg) & AXIADO_MBOX_CSR_EMPTY);
+}
+
+static const struct mbox_chan_ops axiado_mbox_chan_ops = {
+	.send_data	= axiado_mbox_send_data,
+	.startup	= axiado_mbox_startup,
+	.shutdown	= axiado_mbox_shutdown,
+	.last_tx_done	= axiado_mbox_last_tx_done,
+};
+
+static void axiado_mbox_debugfs_remove(void *dentry)
+{
+	debugfs_remove_recursive(dentry);
+}
+
+static int axiado_mbox_probe(struct platform_device *pdev)
+{
+	const struct axiado_mbox_data *drv_data;
+	struct axiado_channel_data *ch_data;
+	struct device *dev = &pdev->dev;
+	struct axiado_mbox *mb;
+	unsigned int irq_idx = 0;
+	unsigned int rx_chan;
+	unsigned int i;
+	int ret;
+
+	drv_data = device_get_match_data(dev);
+	if (!drv_data)
+		return -ENODEV;
+
+	mb = devm_kzalloc(dev, sizeof(*mb), GFP_KERNEL);
+	if (!mb)
+		return -ENOMEM;
+
+	mb->mbox.dev = dev;
+	mb->mbox.num_chans = drv_data->num_chans;
+
+	mb->mbox.chans = devm_kcalloc(&pdev->dev,
+				      drv_data->num_chans,
+				      sizeof(*mb->mbox.chans),
+				      GFP_KERNEL);
+	if (!mb->mbox.chans)
+		return -ENOMEM;
+
+	mb->tx_base = devm_platform_ioremap_resource_byname(pdev, "tx");
+	if (IS_ERR(mb->tx_base))
+		return PTR_ERR(mb->tx_base);
+
+	mb->rx_base = devm_platform_ioremap_resource_byname(pdev, "rx");
+	if (IS_ERR(mb->rx_base))
+		return PTR_ERR(mb->rx_base);
+
+	ch_data = devm_kcalloc(&pdev->dev,
+			       drv_data->num_chans,
+			       sizeof(*ch_data),
+			       GFP_KERNEL);
+	if (!ch_data)
+		return -ENOMEM;
+
+	mb->debugfs_dir = debugfs_create_dir(dev_name(dev), NULL);
+	ret = devm_add_action_or_reset(dev, axiado_mbox_debugfs_remove,
+				       mb->debugfs_dir);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < drv_data->num_chans; i++) {
+		char name[16];
+
+		ch_data[i].channel_num = i;
+		ch_data[i].chan = &mb->mbox.chans[i];
+
+		mb->mbox.chans[i].con_priv = &ch_data[i];
+
+		snprintf(name, sizeof(name), "chan%u-errors", i);
+		debugfs_create_atomic_t(name, 0444, mb->debugfs_dir,
+					&ch_data[i].fifo_errors);
+
+		if (i < AXIADO_MBOX_TX_CHANS) {
+			ch_data[i].mbox_reg = mb->tx_base + (i * AXIADO_MBOX_CHAN_STRIDE);
+			ch_data[i].csr_reg = mb->tx_base + AXIADO_MBOX_TX_REG_STRIDE +
+					       (i * AXIADO_MBOX_CHAN_STRIDE);
+			ch_data[i].irq = -1;
+			continue;
+		}
+
+		ch_data[i].rx_buffer = devm_kzalloc(dev, drv_data->msg_size,
+						    GFP_KERNEL);
+		if (!ch_data[i].rx_buffer)
+			return -ENOMEM;
+
+		rx_chan = i - AXIADO_MBOX_TX_CHANS;
+		ch_data[i].mbox_reg = mb->rx_base +
+				       (rx_chan * AXIADO_MBOX_CHAN_STRIDE);
+		ch_data[i].csr_reg = mb->rx_base + AXIADO_MBOX_RX_REG_STRIDE +
+				      (rx_chan * AXIADO_MBOX_CHAN_STRIDE);
+		ch_data[i].irq = platform_get_irq(pdev, irq_idx++);
+		if (ch_data[i].irq < 0)
+			return dev_err_probe(dev, ch_data[i].irq,
+					     "Failed to get IRQ for channel %u\n", i);
+
+		ret = devm_request_threaded_irq(dev, ch_data[i].irq, NULL,
+						axiado_rx_thread,
+						IRQF_ONESHOT | IRQF_NO_AUTOEN,
+						dev_name(dev), &ch_data[i]);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "Failed to request IRQ for channel %u\n", i);
+
+		dev_dbg(dev, "RX chan %u -> irq %d\n", i, ch_data[i].irq);
+	}
+
+	platform_set_drvdata(pdev, mb);
+	mb->drv_data = drv_data;
+	mb->mbox.ops = &axiado_mbox_chan_ops;
+	mb->mbox.txdone_irq = false;
+	mb->mbox.txdone_poll = true;
+	mb->mbox.txpoll_period = 5;
+
+	return devm_mbox_controller_register(dev, &mb->mbox);
+}
+
+static const struct axiado_mbox_data axiado_drv_data = {
+	.num_chans = AXIADO_MBOX_TX_CHANS + AXIADO_MBOX_RX_CHANS,
+	.msg_size = 256,
+};
+
+static const struct of_device_id axiado_mbox_of_match[] = {
+	{ .compatible = "axiado,ax3005-mailbox", .data = &axiado_drv_data },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, axiado_mbox_of_match);
+
+static struct platform_driver axiado_mbox_driver = {
+	.driver = {
+		.name = "axiado-mailbox",
+		.of_match_table = axiado_mbox_of_match,
+	},
+	.probe = axiado_mbox_probe,
+};
+module_platform_driver(axiado_mbox_driver);
+
+MODULE_AUTHOR("Axiado Corporation");
+MODULE_DESCRIPTION("Axiado Mailbox driver");
+MODULE_LICENSE("GPL");