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, 289 insertions, 0 deletions

diff --git a/drivers/nvmem/microchip-otpc.c b/drivers/nvmem/microchip-otpc.c
new file mode 100644
index 000000000..df979e854
--- /dev/null
+++ b/drivers/nvmem/microchip-otpc.c
@@ -0,0 +1,289 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * OTP Memory controller
+ *
+ * Copyright (C) 2022 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Claudiu Beznea <claudiu.beznea@microchip.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#define MCHP_OTPC_CR			(0x0)
+#define MCHP_OTPC_CR_READ		BIT(6)
+#define MCHP_OTPC_MR			(0x4)
+#define MCHP_OTPC_MR_ADDR		GENMASK(31, 16)
+#define MCHP_OTPC_AR			(0x8)
+#define MCHP_OTPC_SR			(0xc)
+#define MCHP_OTPC_SR_READ		BIT(6)
+#define MCHP_OTPC_HR			(0x20)
+#define MCHP_OTPC_HR_SIZE		GENMASK(15, 8)
+#define MCHP_OTPC_DR			(0x24)
+
+#define MCHP_OTPC_NAME			"mchp-otpc"
+#define MCHP_OTPC_SIZE			(11 * 1024)
+
+/**
+ * struct mchp_otpc - OTPC private data structure
+ * @base: base address
+ * @dev: struct device pointer
+ * @packets: list of packets in OTP memory
+ * @npackets: number of packets in OTP memory
+ */
+struct mchp_otpc {
+	void __iomem *base;
+	struct device *dev;
+	struct list_head packets;
+	u32 npackets;
+};
+
+/**
+ * struct mchp_otpc_packet - OTPC packet data structure
+ * @list: list head
+ * @id: packet ID
+ * @offset: packet offset (in words) in OTP memory
+ */
+struct mchp_otpc_packet {
+	struct list_head list;
+	u32 id;
+	u32 offset;
+};
+
+static struct mchp_otpc_packet *mchp_otpc_id_to_packet(struct mchp_otpc *otpc,
+						       u32 id)
+{
+	struct mchp_otpc_packet *packet;
+
+	if (id >= otpc->npackets)
+		return NULL;
+
+	list_for_each_entry(packet, &otpc->packets, list) {
+		if (packet->id == id)
+			return packet;
+	}
+
+	return NULL;
+}
+
+static int mchp_otpc_prepare_read(struct mchp_otpc *otpc,
+				  unsigned int offset)
+{
+	u32 tmp;
+
+	/* Set address. */
+	tmp = readl_relaxed(otpc->base + MCHP_OTPC_MR);
+	tmp &= ~MCHP_OTPC_MR_ADDR;
+	tmp |= FIELD_PREP(MCHP_OTPC_MR_ADDR, offset);
+	writel_relaxed(tmp, otpc->base + MCHP_OTPC_MR);
+
+	/* Set read. */
+	tmp = readl_relaxed(otpc->base + MCHP_OTPC_CR);
+	tmp |= MCHP_OTPC_CR_READ;
+	writel_relaxed(tmp, otpc->base + MCHP_OTPC_CR);
+
+	/* Wait for packet to be transferred into temporary buffers. */
+	return read_poll_timeout(readl_relaxed, tmp, !(tmp & MCHP_OTPC_SR_READ),
+				 10000, 2000, false, otpc->base + MCHP_OTPC_SR);
+}
+
+/*
+ * OTPC memory is organized into packets. Each packets contains a header and
+ * a payload. Header is 4 bytes long and contains the size of the payload.
+ * Payload size varies. The memory footprint is something as follows:
+ *
+ * Memory offset  Memory footprint     Packet ID
+ * -------------  ----------------     ---------
+ *
+ * 0x0            +------------+   <-- packet 0
+ *                | header  0  |
+ * 0x4            +------------+
+ *                | payload 0  |
+ *                .            .
+ *                .    ...     .
+ *                .            .
+ * offset1        +------------+   <-- packet 1
+ *                | header  1  |
+ * offset1 + 0x4  +------------+
+ *                | payload 1  |
+ *                .            .
+ *                .    ...     .
+ *                .            .
+ * offset2        +------------+   <-- packet 2
+ *                .            .
+ *                .    ...     .
+ *                .            .
+ * offsetN        +------------+   <-- packet N
+ *                | header  N  |
+ * offsetN + 0x4  +------------+
+ *                | payload N  |
+ *                .            .
+ *                .    ...     .
+ *                .            .
+ *                +------------+
+ *
+ * where offset1, offset2, offsetN depends on the size of payload 0, payload 1,
+ * payload N-1.
+ *
+ * The access to memory is done on a per packet basis: the control registers
+ * need to be updated with an offset address (within a packet range) and the
+ * data registers will be update by controller with information contained by
+ * that packet. E.g. if control registers are updated with any address within
+ * the range [offset1, offset2) the data registers are updated by controller
+ * with packet 1. Header data is accessible though MCHP_OTPC_HR register.
+ * Payload data is accessible though MCHP_OTPC_DR and MCHP_OTPC_AR registers.
+ * There is no direct mapping b/w the offset requested by software and the
+ * offset returned by hardware.
+ *
+ * For this, the read function will return the first requested bytes in the
+ * packet. The user will have to be aware of the memory footprint before doing
+ * the read request.
+ */
+static int mchp_otpc_read(void *priv, unsigned int off, void *val,
+			  size_t bytes)
+{
+	struct mchp_otpc *otpc = priv;
+	struct mchp_otpc_packet *packet;
+	u32 *buf = val;
+	u32 offset;
+	size_t len = 0;
+	int ret, payload_size;
+
+	/*
+	 * We reach this point with off being multiple of stride = 4 to
+	 * be able to cross the subsystem. Inside the driver we use continuous
+	 * unsigned integer numbers for packet id, thus divide off by 4
+	 * before passing it to mchp_otpc_id_to_packet().
+	 */
+	packet = mchp_otpc_id_to_packet(otpc, off / 4);
+	if (!packet)
+		return -EINVAL;
+	offset = packet->offset;
+
+	while (len < bytes) {
+		ret = mchp_otpc_prepare_read(otpc, offset);
+		if (ret)
+			return ret;
+
+		/* Read and save header content. */
+		*buf++ = readl_relaxed(otpc->base + MCHP_OTPC_HR);
+		len += sizeof(*buf);
+		offset++;
+		if (len >= bytes)
+			break;
+
+		/* Read and save payload content. */
+		payload_size = FIELD_GET(MCHP_OTPC_HR_SIZE, *(buf - 1));
+		writel_relaxed(0UL, otpc->base + MCHP_OTPC_AR);
+		do {
+			*buf++ = readl_relaxed(otpc->base + MCHP_OTPC_DR);
+			len += sizeof(*buf);
+			offset++;
+			payload_size--;
+		} while (payload_size >= 0 && len < bytes);
+	}
+
+	return 0;
+}
+
+static int mchp_otpc_init_packets_list(struct mchp_otpc *otpc, u32 *size)
+{
+	struct mchp_otpc_packet *packet;
+	u32 word, word_pos = 0, id = 0, npackets = 0, payload_size;
+	int ret;
+
+	INIT_LIST_HEAD(&otpc->packets);
+	*size = 0;
+
+	while (*size < MCHP_OTPC_SIZE) {
+		ret = mchp_otpc_prepare_read(otpc, word_pos);
+		if (ret)
+			return ret;
+
+		word = readl_relaxed(otpc->base + MCHP_OTPC_HR);
+		payload_size = FIELD_GET(MCHP_OTPC_HR_SIZE, word);
+		if (!payload_size)
+			break;
+
+		packet = devm_kzalloc(otpc->dev, sizeof(*packet), GFP_KERNEL);
+		if (!packet)
+			return -ENOMEM;
+
+		packet->id = id++;
+		packet->offset = word_pos;
+		INIT_LIST_HEAD(&packet->list);
+		list_add_tail(&packet->list, &otpc->packets);
+
+		/* Count size by adding header and paload sizes. */
+		*size += 4 * (payload_size + 1);
+		/* Next word: this packet (header, payload) position + 1. */
+		word_pos += payload_size + 2;
+
+		npackets++;
+	}
+
+	otpc->npackets = npackets;
+
+	return 0;
+}
+
+static struct nvmem_config mchp_nvmem_config = {
+	.name = MCHP_OTPC_NAME,
+	.type = NVMEM_TYPE_OTP,
+	.read_only = true,
+	.word_size = 4,
+	.stride = 4,
+	.reg_read = mchp_otpc_read,
+};
+
+static int mchp_otpc_probe(struct platform_device *pdev)
+{
+	struct nvmem_device *nvmem;
+	struct mchp_otpc *otpc;
+	u32 size;
+	int ret;
+
+	otpc = devm_kzalloc(&pdev->dev, sizeof(*otpc), GFP_KERNEL);
+	if (!otpc)
+		return -ENOMEM;
+
+	otpc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(otpc->base))
+		return PTR_ERR(otpc->base);
+
+	otpc->dev = &pdev->dev;
+	ret = mchp_otpc_init_packets_list(otpc, &size);
+	if (ret)
+		return ret;
+
+	mchp_nvmem_config.dev = otpc->dev;
+	mchp_nvmem_config.add_legacy_fixed_of_cells = true;
+	mchp_nvmem_config.size = size;
+	mchp_nvmem_config.priv = otpc;
+	nvmem = devm_nvmem_register(&pdev->dev, &mchp_nvmem_config);
+
+	return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static const struct of_device_id __maybe_unused mchp_otpc_ids[] = {
+	{ .compatible = "microchip,sama7g5-otpc", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, mchp_otpc_ids);
+
+static struct platform_driver mchp_otpc_driver = {
+	.probe = mchp_otpc_probe,
+	.driver = {
+		.name = MCHP_OTPC_NAME,
+		.of_match_table = of_match_ptr(mchp_otpc_ids),
+	},
+};
+module_platform_driver(mchp_otpc_driver);
+
+MODULE_AUTHOR("Claudiu Beznea <claudiu.beznea@microchip.com>");
+MODULE_DESCRIPTION("Microchip SAMA7G5 OTPC driver");
+MODULE_LICENSE("GPL");