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, 333 insertions, 0 deletions

diff --git a/drivers/hwmon/max127.c b/drivers/hwmon/max127.c
new file mode 100644
index 000000000..b294e86d5
--- /dev/null
+++ b/drivers/hwmon/max127.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Hardware monitoring driver for MAX127.
+ *
+ * Copyright (c) 2020 Facebook Inc.
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+
+/*
+ * MAX127 Control Byte. Refer to MAX127 datasheet, Table 1 "Control-Byte
+ * Format" for details.
+ */
+#define MAX127_CTRL_START	BIT(7)
+#define MAX127_CTRL_SEL_SHIFT	4
+#define MAX127_CTRL_RNG		BIT(3)
+#define MAX127_CTRL_BIP		BIT(2)
+#define MAX127_CTRL_PD1		BIT(1)
+#define MAX127_CTRL_PD0		BIT(0)
+
+#define MAX127_NUM_CHANNELS	8
+#define MAX127_SET_CHANNEL(ch)	(((ch) & 7) << MAX127_CTRL_SEL_SHIFT)
+
+/*
+ * MAX127 channel input ranges. Refer to MAX127 datasheet, Table 3 "Range
+ * and Polarity Selection" for details.
+ */
+#define MAX127_FULL_RANGE	10000	/* 10V */
+#define MAX127_HALF_RANGE	5000	/* 5V */
+
+/*
+ * MAX127 returns 2 bytes at read:
+ *   - the first byte contains data[11:4].
+ *   - the second byte contains data[3:0] (MSB) and 4 dummy 0s (LSB).
+ * Refer to MAX127 datasheet, "Read a Conversion (Read Cycle)" section
+ * for details.
+ */
+#define MAX127_DATA_LEN		2
+#define MAX127_DATA_SHIFT	4
+
+#define MAX127_SIGN_BIT		BIT(11)
+
+struct max127_data {
+	struct i2c_client *client;
+	u8 ctrl_byte[MAX127_NUM_CHANNELS];
+};
+
+static int max127_select_channel(struct i2c_client *client, u8 ctrl_byte)
+{
+	int status;
+	struct i2c_msg msg = {
+		.addr = client->addr,
+		.flags = 0,
+		.len = sizeof(ctrl_byte),
+		.buf = &ctrl_byte,
+	};
+
+	status = i2c_transfer(client->adapter, &msg, 1);
+	if (status < 0)
+		return status;
+	if (status != 1)
+		return -EIO;
+
+	return 0;
+}
+
+static int max127_read_channel(struct i2c_client *client, long *val)
+{
+	int status;
+	u8 i2c_data[MAX127_DATA_LEN];
+	struct i2c_msg msg = {
+		.addr = client->addr,
+		.flags = I2C_M_RD,
+		.len = sizeof(i2c_data),
+		.buf = i2c_data,
+	};
+
+	status = i2c_transfer(client->adapter, &msg, 1);
+	if (status < 0)
+		return status;
+	if (status != 1)
+		return -EIO;
+
+	*val = (i2c_data[1] >> MAX127_DATA_SHIFT) |
+		((u16)i2c_data[0] << MAX127_DATA_SHIFT);
+	return 0;
+}
+
+static long max127_process_raw(u8 ctrl_byte, long raw)
+{
+	long scale, weight;
+
+	/*
+	 * MAX127's data coding is binary in unipolar mode with 1 LSB =
+	 * (Full-Scale/4096) and two’s complement binary in bipolar mode
+	 * with 1 LSB = [(2 x |FS|)/4096].
+	 * Refer to MAX127 datasheet, "Transfer Function" section for
+	 * details.
+	 */
+	scale = (ctrl_byte & MAX127_CTRL_RNG) ? MAX127_FULL_RANGE :
+						MAX127_HALF_RANGE;
+	if (ctrl_byte & MAX127_CTRL_BIP) {
+		weight = (raw & MAX127_SIGN_BIT);
+		raw &= ~MAX127_SIGN_BIT;
+		raw -= weight;
+		raw *= 2;
+	}
+
+	return raw * scale / 4096;
+}
+
+static int max127_read_input(struct max127_data *data, int channel, long *val)
+{
+	long raw;
+	int status;
+	struct i2c_client *client = data->client;
+	u8 ctrl_byte = data->ctrl_byte[channel];
+
+	status = max127_select_channel(client, ctrl_byte);
+	if (status)
+		return status;
+
+	status = max127_read_channel(client, &raw);
+	if (status)
+		return status;
+
+	*val = max127_process_raw(ctrl_byte, raw);
+	return 0;
+}
+
+static int max127_read_min(struct max127_data *data, int channel, long *val)
+{
+	u8 rng_bip = (data->ctrl_byte[channel] >> 2) & 3;
+	static const int min_input_map[4] = {
+		0,			/* RNG=0, BIP=0 */
+		-MAX127_HALF_RANGE,	/* RNG=0, BIP=1 */
+		0,			/* RNG=1, BIP=0 */
+		-MAX127_FULL_RANGE,	/* RNG=1, BIP=1 */
+	};
+
+	*val = min_input_map[rng_bip];
+	return 0;
+}
+
+static int max127_read_max(struct max127_data *data, int channel, long *val)
+{
+	u8 rng_bip = (data->ctrl_byte[channel] >> 2) & 3;
+	static const int max_input_map[4] = {
+		MAX127_HALF_RANGE,	/* RNG=0, BIP=0 */
+		MAX127_HALF_RANGE,	/* RNG=0, BIP=1 */
+		MAX127_FULL_RANGE,	/* RNG=1, BIP=0 */
+		MAX127_FULL_RANGE,	/* RNG=1, BIP=1 */
+	};
+
+	*val = max_input_map[rng_bip];
+	return 0;
+}
+
+static int max127_write_min(struct max127_data *data, int channel, long val)
+{
+	u8 ctrl;
+
+	ctrl = data->ctrl_byte[channel];
+	if (val <= -MAX127_FULL_RANGE) {
+		ctrl |= (MAX127_CTRL_RNG | MAX127_CTRL_BIP);
+	} else if (val < 0) {
+		ctrl |= MAX127_CTRL_BIP;
+		ctrl &= ~MAX127_CTRL_RNG;
+	} else {
+		ctrl &= ~MAX127_CTRL_BIP;
+	}
+	data->ctrl_byte[channel] = ctrl;
+	return 0;
+}
+
+static int max127_write_max(struct max127_data *data, int channel, long val)
+{
+	if (val >= MAX127_FULL_RANGE)
+		data->ctrl_byte[channel] |= MAX127_CTRL_RNG;
+	else
+		data->ctrl_byte[channel] &= ~MAX127_CTRL_RNG;
+	return 0;
+}
+
+static umode_t max127_is_visible(const void *_data,
+				 enum hwmon_sensor_types type,
+				 u32 attr, int channel)
+{
+	if (type == hwmon_in) {
+		switch (attr) {
+		case hwmon_in_input:
+			return 0444;
+
+		case hwmon_in_min:
+		case hwmon_in_max:
+			return 0644;
+
+		default:
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static int max127_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	int status;
+	struct max127_data *data = dev_get_drvdata(dev);
+
+	if (type != hwmon_in)
+		return -EOPNOTSUPP;
+
+	switch (attr) {
+	case hwmon_in_input:
+		status = max127_read_input(data, channel, val);
+		break;
+
+	case hwmon_in_min:
+		status = max127_read_min(data, channel, val);
+		break;
+
+	case hwmon_in_max:
+		status = max127_read_max(data, channel, val);
+		break;
+
+	default:
+		status = -EOPNOTSUPP;
+		break;
+	}
+
+	return status;
+}
+
+static int max127_write(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long val)
+{
+	int status;
+	struct max127_data *data = dev_get_drvdata(dev);
+
+	if (type != hwmon_in)
+		return -EOPNOTSUPP;
+
+	switch (attr) {
+	case hwmon_in_min:
+		status = max127_write_min(data, channel, val);
+		break;
+
+	case hwmon_in_max:
+		status = max127_write_max(data, channel, val);
+		break;
+
+	default:
+		status = -EOPNOTSUPP;
+		break;
+	}
+
+	return status;
+}
+
+static const struct hwmon_ops max127_hwmon_ops = {
+	.is_visible = max127_is_visible,
+	.read = max127_read,
+	.write = max127_write,
+};
+
+static const struct hwmon_channel_info * const max127_info[] = {
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX,
+			   HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX,
+			   HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX,
+			   HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX,
+			   HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX,
+			   HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX,
+			   HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX,
+			   HWMON_I_INPUT | HWMON_I_MIN | HWMON_I_MAX),
+	NULL,
+};
+
+static const struct hwmon_chip_info max127_chip_info = {
+	.ops = &max127_hwmon_ops,
+	.info = max127_info,
+};
+
+static int max127_probe(struct i2c_client *client)
+{
+	int i;
+	struct device *hwmon_dev;
+	struct max127_data *data;
+	struct device *dev = &client->dev;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	for (i = 0; i < ARRAY_SIZE(data->ctrl_byte); i++)
+		data->ctrl_byte[i] = (MAX127_CTRL_START |
+				      MAX127_SET_CHANNEL(i));
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
+							 data,
+							 &max127_chip_info,
+							 NULL);
+
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id max127_id[] = {
+	{ .name = "max127" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max127_id);
+
+static struct i2c_driver max127_driver = {
+	.driver = {
+		.name	= "max127",
+	},
+	.probe		= max127_probe,
+	.id_table	= max127_id,
+};
+
+module_i2c_driver(max127_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mike Choi <mikechoi@fb.com>");
+MODULE_AUTHOR("Tao Ren <rentao.bupt@gmail.com>");
+MODULE_DESCRIPTION("MAX127 Hardware Monitoring driver");