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, 362 insertions, 0 deletions

diff --git a/drivers/nvmem/rave-sp-eeprom.c b/drivers/nvmem/rave-sp-eeprom.c
new file mode 100644
index 000000000..9ecf3873c
--- /dev/null
+++ b/drivers/nvmem/rave-sp-eeprom.c
@@ -0,0 +1,362 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * EEPROM driver for RAVE SP
+ *
+ * Copyright (C) 2018 Zodiac Inflight Innovations
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/mfd/rave-sp.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/sizes.h>
+
+/**
+ * enum rave_sp_eeprom_access_type - Supported types of EEPROM access
+ *
+ * @RAVE_SP_EEPROM_WRITE:	EEPROM write
+ * @RAVE_SP_EEPROM_READ:	EEPROM read
+ */
+enum rave_sp_eeprom_access_type {
+	RAVE_SP_EEPROM_WRITE = 0,
+	RAVE_SP_EEPROM_READ  = 1,
+};
+
+/**
+ * enum rave_sp_eeprom_header_size - EEPROM command header sizes
+ *
+ * @RAVE_SP_EEPROM_HEADER_SMALL: EEPROM header size for "small" devices (< 8K)
+ * @RAVE_SP_EEPROM_HEADER_BIG:	 EEPROM header size for "big" devices (> 8K)
+ */
+enum rave_sp_eeprom_header_size {
+	RAVE_SP_EEPROM_HEADER_SMALL = 4U,
+	RAVE_SP_EEPROM_HEADER_BIG   = 5U,
+};
+#define RAVE_SP_EEPROM_HEADER_MAX	RAVE_SP_EEPROM_HEADER_BIG
+
+#define	RAVE_SP_EEPROM_PAGE_SIZE	32U
+
+/**
+ * struct rave_sp_eeprom_page - RAVE SP EEPROM page
+ *
+ * @type:	Access type (see enum rave_sp_eeprom_access_type)
+ * @success:	Success flag (Success = 1, Failure = 0)
+ * @data:	Read data
+ *
+ * Note this structure corresponds to RSP_*_EEPROM payload from RAVE
+ * SP ICD
+ */
+struct rave_sp_eeprom_page {
+	u8  type;
+	u8  success;
+	u8  data[RAVE_SP_EEPROM_PAGE_SIZE];
+} __packed;
+
+/**
+ * struct rave_sp_eeprom - RAVE SP EEPROM device
+ *
+ * @sp:			Pointer to parent RAVE SP device
+ * @mutex:		Lock protecting access to EEPROM
+ * @address:		EEPROM device address
+ * @header_size:	Size of EEPROM command header for this device
+ * @dev:		Pointer to corresponding struct device used for logging
+ */
+struct rave_sp_eeprom {
+	struct rave_sp *sp;
+	struct mutex mutex;
+	u8 address;
+	unsigned int header_size;
+	struct device *dev;
+};
+
+/**
+ * rave_sp_eeprom_io - Low-level part of EEPROM page access
+ *
+ * @eeprom:	EEPROM device to write to
+ * @type:	EEPROM access type (read or write)
+ * @idx:	number of the EEPROM page
+ * @page:	Data to write or buffer to store result (via page->data)
+ *
+ * This function does all of the low-level work required to perform a
+ * EEPROM access. This includes formatting correct command payload,
+ * sending it and checking received results.
+ *
+ * Returns zero in case of success or negative error code in
+ * case of failure.
+ */
+static int rave_sp_eeprom_io(struct rave_sp_eeprom *eeprom,
+			     enum rave_sp_eeprom_access_type type,
+			     u16 idx,
+			     struct rave_sp_eeprom_page *page)
+{
+	const bool is_write = type == RAVE_SP_EEPROM_WRITE;
+	const unsigned int data_size = is_write ? sizeof(page->data) : 0;
+	const unsigned int cmd_size = eeprom->header_size + data_size;
+	const unsigned int rsp_size =
+		is_write ? sizeof(*page) - sizeof(page->data) : sizeof(*page);
+	unsigned int offset = 0;
+	u8 cmd[RAVE_SP_EEPROM_HEADER_MAX + sizeof(page->data)];
+	int ret;
+
+	if (WARN_ON(cmd_size > sizeof(cmd)))
+		return -EINVAL;
+
+	cmd[offset++] = eeprom->address;
+	cmd[offset++] = 0;
+	cmd[offset++] = type;
+	cmd[offset++] = idx;
+
+	/*
+	 * If there's still room in this command's header it means we
+	 * are talkin to EEPROM that uses 16-bit page numbers and we
+	 * have to specify index's MSB in payload as well.
+	 */
+	if (offset < eeprom->header_size)
+		cmd[offset++] = idx >> 8;
+	/*
+	 * Copy our data to write to command buffer first. In case of
+	 * a read data_size should be zero and memcpy would become a
+	 * no-op
+	 */
+	memcpy(&cmd[offset], page->data, data_size);
+
+	ret = rave_sp_exec(eeprom->sp, cmd, cmd_size, page, rsp_size);
+	if (ret)
+		return ret;
+
+	if (page->type != type)
+		return -EPROTO;
+
+	if (!page->success)
+		return -EIO;
+
+	return 0;
+}
+
+/**
+ * rave_sp_eeprom_page_access - Access single EEPROM page
+ *
+ * @eeprom:	EEPROM device to access
+ * @type:	Access type to perform (read or write)
+ * @offset:	Offset within EEPROM to access
+ * @data:	Data buffer
+ * @data_len:	Size of the data buffer
+ *
+ * This function performs a generic access to a single page or a
+ * portion thereof. Requested access MUST NOT cross the EEPROM page
+ * boundary.
+ *
+ * Returns zero in case of success or negative error code in
+ * case of failure.
+ */
+static int
+rave_sp_eeprom_page_access(struct rave_sp_eeprom *eeprom,
+			   enum rave_sp_eeprom_access_type type,
+			   unsigned int offset, u8 *data,
+			   size_t data_len)
+{
+	const unsigned int page_offset = offset % RAVE_SP_EEPROM_PAGE_SIZE;
+	const unsigned int page_nr     = offset / RAVE_SP_EEPROM_PAGE_SIZE;
+	struct rave_sp_eeprom_page page;
+	int ret;
+
+	/*
+	 * This function will not work if data access we've been asked
+	 * to do is crossing EEPROM page boundary. Normally this
+	 * should never happen and getting here would indicate a bug
+	 * in the code.
+	 */
+	if (WARN_ON(data_len > sizeof(page.data) - page_offset))
+		return -EINVAL;
+
+	if (type == RAVE_SP_EEPROM_WRITE) {
+		/*
+		 * If doing a partial write we need to do a read first
+		 * to fill the rest of the page with correct data.
+		 */
+		if (data_len < RAVE_SP_EEPROM_PAGE_SIZE) {
+			ret = rave_sp_eeprom_io(eeprom, RAVE_SP_EEPROM_READ,
+						page_nr, &page);
+			if (ret)
+				return ret;
+		}
+
+		memcpy(&page.data[page_offset], data, data_len);
+	}
+
+	ret = rave_sp_eeprom_io(eeprom, type, page_nr, &page);
+	if (ret)
+		return ret;
+
+	/*
+	 * Since we receive the result of the read via 'page.data'
+	 * buffer we need to copy that to 'data'
+	 */
+	if (type == RAVE_SP_EEPROM_READ)
+		memcpy(data, &page.data[page_offset], data_len);
+
+	return 0;
+}
+
+/**
+ * rave_sp_eeprom_access - Access EEPROM data
+ *
+ * @eeprom:	EEPROM device to access
+ * @type:	Access type to perform (read or write)
+ * @offset:	Offset within EEPROM to access
+ * @data:	Data buffer
+ * @data_len:	Size of the data buffer
+ *
+ * This function performs a generic access (either read or write) at
+ * arbitrary offset (not necessary page aligned) of arbitrary length
+ * (is not constrained by EEPROM page size).
+ *
+ * Returns zero in case of success or negative error code in case of
+ * failure.
+ */
+static int rave_sp_eeprom_access(struct rave_sp_eeprom *eeprom,
+				 enum rave_sp_eeprom_access_type type,
+				 unsigned int offset, u8 *data,
+				 unsigned int data_len)
+{
+	unsigned int residue;
+	unsigned int chunk;
+	unsigned int head;
+	int ret;
+
+	mutex_lock(&eeprom->mutex);
+
+	head    = offset % RAVE_SP_EEPROM_PAGE_SIZE;
+	residue = data_len;
+
+	do {
+		/*
+		 * First iteration, if we are doing an access that is
+		 * not 32-byte aligned, we need to access only data up
+		 * to a page boundary to avoid corssing it in
+		 * rave_sp_eeprom_page_access()
+		 */
+		if (unlikely(head)) {
+			chunk = RAVE_SP_EEPROM_PAGE_SIZE - head;
+			/*
+			 * This can only happen once per
+			 * rave_sp_eeprom_access() call, so we set
+			 * head to zero to process all the other
+			 * iterations normally.
+			 */
+			head  = 0;
+		} else {
+			chunk = RAVE_SP_EEPROM_PAGE_SIZE;
+		}
+
+		/*
+		 * We should never read more that 'residue' bytes
+		 */
+		chunk = min(chunk, residue);
+		ret = rave_sp_eeprom_page_access(eeprom, type, offset,
+						 data, chunk);
+		if (ret)
+			goto out;
+
+		residue -= chunk;
+		offset  += chunk;
+		data    += chunk;
+	} while (residue);
+out:
+	mutex_unlock(&eeprom->mutex);
+	return ret;
+}
+
+static int rave_sp_eeprom_reg_read(void *eeprom, unsigned int offset,
+				   void *val, size_t bytes)
+{
+	return rave_sp_eeprom_access(eeprom, RAVE_SP_EEPROM_READ,
+				     offset, val, bytes);
+}
+
+static int rave_sp_eeprom_reg_write(void *eeprom, unsigned int offset,
+				    void *val, size_t bytes)
+{
+	return rave_sp_eeprom_access(eeprom, RAVE_SP_EEPROM_WRITE,
+				     offset, val, bytes);
+}
+
+static int rave_sp_eeprom_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rave_sp *sp = dev_get_drvdata(dev->parent);
+	struct device_node *np = dev->of_node;
+	struct nvmem_config config = { 0 };
+	struct rave_sp_eeprom *eeprom;
+	struct nvmem_device *nvmem;
+	u32 reg[2], size;
+
+	if (of_property_read_u32_array(np, "reg", reg, ARRAY_SIZE(reg))) {
+		dev_err(dev, "Failed to parse \"reg\" property\n");
+		return -EINVAL;
+	}
+
+	size = reg[1];
+	/*
+	 * Per ICD, we have no more than 2 bytes to specify EEPROM
+	 * page.
+	 */
+	if (size > U16_MAX * RAVE_SP_EEPROM_PAGE_SIZE) {
+		dev_err(dev, "Specified size is too big\n");
+		return -EINVAL;
+	}
+
+	eeprom = devm_kzalloc(dev, sizeof(*eeprom), GFP_KERNEL);
+	if (!eeprom)
+		return -ENOMEM;
+
+	eeprom->address = reg[0];
+	eeprom->sp      = sp;
+	eeprom->dev     = dev;
+
+	if (size > SZ_8K)
+		eeprom->header_size = RAVE_SP_EEPROM_HEADER_BIG;
+	else
+		eeprom->header_size = RAVE_SP_EEPROM_HEADER_SMALL;
+
+	mutex_init(&eeprom->mutex);
+
+	config.id		= -1;
+	of_property_read_string(np, "zii,eeprom-name", &config.name);
+	config.priv		= eeprom;
+	config.dev		= dev;
+	config.add_legacy_fixed_of_cells	= true;
+	config.size		= size;
+	config.reg_read		= rave_sp_eeprom_reg_read;
+	config.reg_write	= rave_sp_eeprom_reg_write;
+	config.word_size	= 1;
+	config.stride		= 1;
+
+	nvmem = devm_nvmem_register(dev, &config);
+
+	return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static const struct of_device_id rave_sp_eeprom_of_match[] = {
+	{ .compatible = "zii,rave-sp-eeprom" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, rave_sp_eeprom_of_match);
+
+static struct platform_driver rave_sp_eeprom_driver = {
+	.probe = rave_sp_eeprom_probe,
+	.driver	= {
+		.name = KBUILD_MODNAME,
+		.of_match_table = rave_sp_eeprom_of_match,
+	},
+};
+module_platform_driver(rave_sp_eeprom_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>");
+MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");
+MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
+MODULE_DESCRIPTION("RAVE SP EEPROM driver");