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, 351 insertions, 0 deletions

diff --git a/drivers/nvmem/ee1004.c b/drivers/nvmem/ee1004.c
new file mode 100644
index 000000000..923f404a4
--- /dev/null
+++ b/drivers/nvmem/ee1004.c
@@ -0,0 +1,351 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ee1004 - driver for DDR4 SPD EEPROMs
+ *
+ * Copyright (C) 2017-2019 Jean Delvare
+ *
+ * Based on the at24 driver:
+ * Copyright (C) 2005-2007 David Brownell
+ * Copyright (C) 2008 Wolfram Sang, Pengutronix
+ */
+
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/nvmem-provider.h>
+
+/*
+ * DDR4 memory modules use special EEPROMs following the Jedec EE1004
+ * specification. These are 512-byte EEPROMs using a single I2C address
+ * in the 0x50-0x57 range for data. One of two 256-byte page is selected
+ * by writing a command to I2C address 0x36 or 0x37 on the same I2C bus.
+ *
+ * Therefore we need to request these 2 additional addresses, and serialize
+ * access to all such EEPROMs with a single mutex.
+ *
+ * We assume it is safe to read up to 32 bytes at once from these EEPROMs.
+ * We use SMBus access even if I2C is available, these EEPROMs are small
+ * enough, and reading from them infrequent enough, that we favor simplicity
+ * over performance.
+ */
+
+#define EE1004_MAX_BUSSES		8
+#define EE1004_ADDR_SET_PAGE		0x36
+#define EE1004_NUM_PAGES		2
+#define EE1004_PAGE_SIZE		256
+#define EE1004_PAGE_SHIFT		8
+#define EE1004_EEPROM_SIZE		(EE1004_PAGE_SIZE * EE1004_NUM_PAGES)
+
+/*
+ * Mutex protects ee1004_set_page and ee1004_dev_count, and must be held
+ * from page selection to end of read.
+ */
+static DEFINE_MUTEX(ee1004_bus_lock);
+
+static struct ee1004_bus_data {
+	struct i2c_adapter *adap;
+	struct i2c_client *set_page[EE1004_NUM_PAGES];
+	unsigned int dev_count;
+	int current_page;
+} ee1004_bus_data[EE1004_MAX_BUSSES];
+
+static const struct i2c_device_id ee1004_ids[] = {
+	{ "ee1004" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ee1004_ids);
+
+/*-------------------------------------------------------------------------*/
+
+static struct ee1004_bus_data *ee1004_get_bus_data(struct i2c_adapter *adap)
+{
+	int i;
+
+	for (i = 0; i < EE1004_MAX_BUSSES; i++)
+		if (ee1004_bus_data[i].adap == adap)
+			return ee1004_bus_data + i;
+
+	/* If not existent yet, create new entry */
+	for (i = 0; i < EE1004_MAX_BUSSES; i++)
+		if (!ee1004_bus_data[i].adap) {
+			ee1004_bus_data[i].adap = adap;
+			return ee1004_bus_data + i;
+		}
+
+	return NULL;
+}
+
+static int ee1004_get_current_page(struct ee1004_bus_data *bd)
+{
+	int err;
+
+	err = i2c_smbus_read_byte(bd->set_page[0]);
+	if (err == -ENXIO) {
+		/* Nack means page 1 is selected */
+		return 1;
+	}
+	if (err < 0) {
+		/* Anything else is a real error, bail out */
+		return err;
+	}
+
+	/* Ack means page 0 is selected, returned value meaningless */
+	return 0;
+}
+
+static int ee1004_set_current_page(struct i2c_client *client, int page)
+{
+	struct ee1004_bus_data *bd = i2c_get_clientdata(client);
+	int ret;
+
+	if (page == bd->current_page)
+		return 0;
+
+	/* Data is ignored */
+	ret = i2c_smbus_write_byte(bd->set_page[page], 0x00);
+	/*
+	 * Don't give up just yet. Some memory modules will select the page
+	 * but not ack the command. Check which page is selected now.
+	 */
+	if (ret == -ENXIO && ee1004_get_current_page(bd) == page)
+		ret = 0;
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to select page %d (%d)\n", page, ret);
+		return ret;
+	}
+
+	dev_dbg(&client->dev, "Selected page %d\n", page);
+	bd->current_page = page;
+
+	return 0;
+}
+
+static ssize_t ee1004_eeprom_read(struct i2c_client *client, char *buf,
+				  unsigned int offset, size_t count)
+{
+	int status, page;
+
+	page = offset >> EE1004_PAGE_SHIFT;
+	offset &= (1 << EE1004_PAGE_SHIFT) - 1;
+
+	status = ee1004_set_current_page(client, page);
+	if (status)
+		return status;
+
+	/* Can't cross page boundaries */
+	if (offset + count > EE1004_PAGE_SIZE)
+		count = EE1004_PAGE_SIZE - offset;
+
+	if (count > I2C_SMBUS_BLOCK_MAX)
+		count = I2C_SMBUS_BLOCK_MAX;
+
+	return i2c_smbus_read_i2c_block_data_or_emulated(client, offset, count, buf);
+}
+
+static int ee1004_read(void *priv, unsigned int off, void *val, size_t count)
+{
+	struct i2c_client *client = priv;
+	char *buf = val;
+	int ret;
+
+	if (unlikely(!count))
+		return count;
+
+	if (off + count > EE1004_EEPROM_SIZE)
+		return -EINVAL;
+
+	/*
+	 * Read data from chip, protecting against concurrent access to
+	 * other EE1004 SPD EEPROMs on the same adapter.
+	 */
+	mutex_lock(&ee1004_bus_lock);
+
+	while (count) {
+		ret = ee1004_eeprom_read(client, buf, off, count);
+		if (ret < 0) {
+			mutex_unlock(&ee1004_bus_lock);
+			return ret;
+		}
+
+		buf += ret;
+		off += ret;
+		count -= ret;
+	}
+
+	mutex_unlock(&ee1004_bus_lock);
+
+	return 0;
+}
+
+static void ee1004_probe_temp_sensor(struct i2c_client *client)
+{
+	struct i2c_board_info info = { .type = "jc42" };
+	unsigned short addr = 0x18 | (client->addr & 7);
+	unsigned short addr_list[] = { addr, I2C_CLIENT_END };
+	u8 data[2];
+	int ret;
+
+	/* byte 14, bit 7 is set if temp sensor is present */
+	ret = ee1004_eeprom_read(client, data, 14, 1);
+	if (ret != 1)
+		return;
+
+	if (!(data[0] & BIT(7))) {
+		/*
+		 * If the SPD data suggests that there is no temperature
+		 * sensor, it may still be there for SPD revision 1.0.
+		 * See SPD Annex L, Revision 1 and 2, for details.
+		 * Check DIMM type and SPD revision; if it is a DDR4
+		 * with SPD revision 1.0, check the thermal sensor address
+		 * and instantiate the jc42 driver if a chip is found at
+		 * that address.
+		 * It is not necessary to check if there is a chip at the
+		 * temperature sensor address since i2c_new_scanned_device()
+		 * will do that and return silently if no chip is found.
+		 */
+		ret = ee1004_eeprom_read(client, data, 1, 2);
+		if (ret != 2 || data[0] != 0x10 || data[1] != 0x0c)
+			return;
+	}
+	i2c_new_scanned_device(client->adapter, &info, addr_list, NULL);
+}
+
+static void ee1004_cleanup(int idx, struct ee1004_bus_data *bd)
+{
+	if (--bd->dev_count == 0) {
+		while (--idx >= 0)
+			i2c_unregister_device(bd->set_page[idx]);
+		memset(bd, 0, sizeof(struct ee1004_bus_data));
+	}
+}
+
+static void ee1004_cleanup_bus_data(void *data)
+{
+	struct ee1004_bus_data *bd = data;
+
+	/* Remove page select clients if this is the last device */
+	mutex_lock(&ee1004_bus_lock);
+	ee1004_cleanup(EE1004_NUM_PAGES, bd);
+	mutex_unlock(&ee1004_bus_lock);
+}
+
+static int ee1004_init_bus_data(struct i2c_client *client)
+{
+	struct ee1004_bus_data *bd;
+	int err, cnr = 0;
+
+	bd = ee1004_get_bus_data(client->adapter);
+	if (!bd)
+		return dev_err_probe(&client->dev, -ENOSPC, "Only %d busses supported",
+				     EE1004_MAX_BUSSES);
+
+	i2c_set_clientdata(client, bd);
+
+	if (++bd->dev_count == 1) {
+		/* Use 2 dummy devices for page select command */
+		for (cnr = 0; cnr < EE1004_NUM_PAGES; cnr++) {
+			struct i2c_client *cl;
+
+			cl = i2c_new_dummy_device(client->adapter, EE1004_ADDR_SET_PAGE + cnr);
+			if (IS_ERR(cl)) {
+				err = PTR_ERR(cl);
+				goto err_out;
+			}
+
+			bd->set_page[cnr] = cl;
+		}
+
+		/* Remember current page to avoid unneeded page select */
+		err = ee1004_get_current_page(bd);
+		if (err < 0)
+			goto err_out;
+
+		dev_dbg(&client->dev, "Currently selected page: %d\n", err);
+		bd->current_page = err;
+	}
+
+	return 0;
+
+err_out:
+	ee1004_cleanup(cnr, bd);
+
+	return err;
+}
+
+static int ee1004_probe(struct i2c_client *client)
+{
+	struct nvmem_config config = {
+		.dev = &client->dev,
+		.name = dev_name(&client->dev),
+		.id = NVMEM_DEVID_NONE,
+		.owner = THIS_MODULE,
+		.type = NVMEM_TYPE_EEPROM,
+		.read_only = true,
+		.root_only = false,
+		.reg_read = ee1004_read,
+		.size = EE1004_EEPROM_SIZE,
+		.word_size = 1,
+		.stride = 1,
+		.priv = client,
+		.compat = true,
+		.base_dev = &client->dev,
+	};
+	struct nvmem_device *ndev;
+	int err;
+
+	/* Make sure we can operate on this adapter */
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_READ_I2C_BLOCK) &&
+	    !i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_READ_BYTE_DATA))
+		return -EPFNOSUPPORT;
+
+	err = i2c_smbus_read_byte(client);
+	if (err < 0)
+		return -ENODEV;
+
+	mutex_lock(&ee1004_bus_lock);
+
+	err = ee1004_init_bus_data(client);
+	if (err < 0) {
+		mutex_unlock(&ee1004_bus_lock);
+		return err;
+	}
+
+	ee1004_probe_temp_sensor(client);
+
+	mutex_unlock(&ee1004_bus_lock);
+
+	err = devm_add_action_or_reset(&client->dev, ee1004_cleanup_bus_data,
+				       i2c_get_clientdata(client));
+	if (err < 0)
+		return err;
+
+	ndev = devm_nvmem_register(&client->dev, &config);
+	if (IS_ERR(ndev))
+		return PTR_ERR(ndev);
+
+	dev_info(&client->dev,
+		 "%u byte EE1004-compliant SPD EEPROM, read-only\n",
+		 EE1004_EEPROM_SIZE);
+
+	return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static struct i2c_driver ee1004_driver = {
+	.driver = {
+		.name = "ee1004",
+	},
+	.probe = ee1004_probe,
+	.id_table = ee1004_ids,
+};
+module_i2c_driver(ee1004_driver);
+
+MODULE_DESCRIPTION("Driver for EE1004-compliant DDR4 SPD EEPROMs");
+MODULE_AUTHOR("Jean Delvare");
+MODULE_LICENSE("GPL");