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, 482 insertions, 0 deletions

diff --git a/drivers/hwmon/ltc4245.c b/drivers/hwmon/ltc4245.c
new file mode 100644
index 000000000..d87aa9c32
--- /dev/null
+++ b/drivers/hwmon/ltc4245.c
@@ -0,0 +1,482 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
+ *
+ * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
+ *
+ * This driver is based on the ds1621 and ina209 drivers.
+ *
+ * Datasheet:
+ * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/jiffies.h>
+#include <linux/platform_data/ltc4245.h>
+
+/* Here are names of the chip's registers (a.k.a. commands) */
+enum ltc4245_cmd {
+	LTC4245_STATUS			= 0x00, /* readonly */
+	LTC4245_ALERT			= 0x01,
+	LTC4245_CONTROL			= 0x02,
+	LTC4245_ON			= 0x03,
+	LTC4245_FAULT1			= 0x04,
+	LTC4245_FAULT2			= 0x05,
+	LTC4245_GPIO			= 0x06,
+	LTC4245_ADCADR			= 0x07,
+
+	LTC4245_12VIN			= 0x10,
+	LTC4245_12VSENSE		= 0x11,
+	LTC4245_12VOUT			= 0x12,
+	LTC4245_5VIN			= 0x13,
+	LTC4245_5VSENSE			= 0x14,
+	LTC4245_5VOUT			= 0x15,
+	LTC4245_3VIN			= 0x16,
+	LTC4245_3VSENSE			= 0x17,
+	LTC4245_3VOUT			= 0x18,
+	LTC4245_VEEIN			= 0x19,
+	LTC4245_VEESENSE		= 0x1a,
+	LTC4245_VEEOUT			= 0x1b,
+	LTC4245_GPIOADC			= 0x1c,
+};
+
+struct ltc4245_data {
+	struct i2c_client *client;
+
+	bool valid;
+	unsigned long last_updated; /* in jiffies */
+
+	/* Control registers */
+	u8 cregs[0x08];
+
+	/* Voltage registers */
+	u8 vregs[0x0d];
+
+	/* GPIO ADC registers */
+	bool use_extra_gpios;
+	int gpios[3];
+};
+
+/*
+ * Update the readings from the GPIO pins. If the driver has been configured to
+ * sample all GPIO's as analog voltages, a round-robin sampling method is used.
+ * Otherwise, only the configured GPIO pin is sampled.
+ *
+ * LOCKING: must hold data->update_lock
+ */
+static void ltc4245_update_gpios(struct device *dev)
+{
+	struct ltc4245_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	u8 gpio_curr, gpio_next, gpio_reg;
+	int i;
+
+	/* no extra gpio support, we're basically done */
+	if (!data->use_extra_gpios) {
+		data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10];
+		return;
+	}
+
+	/*
+	 * If the last reading was too long ago, then we mark all old GPIO
+	 * readings as stale by setting them to -EAGAIN
+	 */
+	if (time_after(jiffies, data->last_updated + 5 * HZ)) {
+		for (i = 0; i < ARRAY_SIZE(data->gpios); i++)
+			data->gpios[i] = -EAGAIN;
+	}
+
+	/*
+	 * Get the current GPIO pin
+	 *
+	 * The datasheet calls these GPIO[1-3], but we'll calculate the zero
+	 * based array index instead, and call them GPIO[0-2]. This is much
+	 * easier to think about.
+	 */
+	gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
+	if (gpio_curr > 0)
+		gpio_curr -= 1;
+
+	/* Read the GPIO voltage from the GPIOADC register */
+	data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10];
+
+	/* Find the next GPIO pin to read */
+	gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios);
+
+	/*
+	 * Calculate the correct setting for the GPIO register so it will
+	 * sample the next GPIO pin
+	 */
+	gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6);
+
+	/* Update the GPIO register */
+	i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
+
+	/* Update saved data */
+	data->cregs[LTC4245_GPIO] = gpio_reg;
+}
+
+static struct ltc4245_data *ltc4245_update_device(struct device *dev)
+{
+	struct ltc4245_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	s32 val;
+	int i;
+
+	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+		/* Read control registers -- 0x00 to 0x07 */
+		for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
+			val = i2c_smbus_read_byte_data(client, i);
+			if (unlikely(val < 0))
+				data->cregs[i] = 0;
+			else
+				data->cregs[i] = val;
+		}
+
+		/* Read voltage registers -- 0x10 to 0x1c */
+		for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
+			val = i2c_smbus_read_byte_data(client, i+0x10);
+			if (unlikely(val < 0))
+				data->vregs[i] = 0;
+			else
+				data->vregs[i] = val;
+		}
+
+		/* Update GPIO readings */
+		ltc4245_update_gpios(dev);
+
+		data->last_updated = jiffies;
+		data->valid = true;
+	}
+
+	return data;
+}
+
+/* Return the voltage from the given register in millivolts */
+static int ltc4245_get_voltage(struct device *dev, u8 reg)
+{
+	struct ltc4245_data *data = ltc4245_update_device(dev);
+	const u8 regval = data->vregs[reg - 0x10];
+	u32 voltage = 0;
+
+	switch (reg) {
+	case LTC4245_12VIN:
+	case LTC4245_12VOUT:
+		voltage = regval * 55;
+		break;
+	case LTC4245_5VIN:
+	case LTC4245_5VOUT:
+		voltage = regval * 22;
+		break;
+	case LTC4245_3VIN:
+	case LTC4245_3VOUT:
+		voltage = regval * 15;
+		break;
+	case LTC4245_VEEIN:
+	case LTC4245_VEEOUT:
+		voltage = regval * -55;
+		break;
+	case LTC4245_GPIOADC:
+		voltage = regval * 10;
+		break;
+	default:
+		/* If we get here, the developer messed up */
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	return voltage;
+}
+
+/* Return the current in the given sense register in milliAmperes */
+static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
+{
+	struct ltc4245_data *data = ltc4245_update_device(dev);
+	const u8 regval = data->vregs[reg - 0x10];
+	unsigned int voltage;
+	unsigned int curr;
+
+	/*
+	 * The strange looking conversions that follow are fixed-point
+	 * math, since we cannot do floating point in the kernel.
+	 *
+	 * Step 1: convert sense register to microVolts
+	 * Step 2: convert voltage to milliAmperes
+	 *
+	 * If you play around with the V=IR equation, you come up with
+	 * the following: X uV / Y mOhm == Z mA
+	 *
+	 * With the resistors that are fractions of a milliOhm, we multiply
+	 * the voltage and resistance by 10, to shift the decimal point.
+	 * Now we can use the normal division operator again.
+	 */
+
+	switch (reg) {
+	case LTC4245_12VSENSE:
+		voltage = regval * 250; /* voltage in uV */
+		curr = voltage / 50; /* sense resistor 50 mOhm */
+		break;
+	case LTC4245_5VSENSE:
+		voltage = regval * 125; /* voltage in uV */
+		curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
+		break;
+	case LTC4245_3VSENSE:
+		voltage = regval * 125; /* voltage in uV */
+		curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
+		break;
+	case LTC4245_VEESENSE:
+		voltage = regval * 250; /* voltage in uV */
+		curr = voltage / 100; /* sense resistor 100 mOhm */
+		break;
+	default:
+		/* If we get here, the developer messed up */
+		WARN_ON_ONCE(1);
+		curr = 0;
+		break;
+	}
+
+	return curr;
+}
+
+/* Map from voltage channel index to voltage register */
+
+static const s8 ltc4245_in_regs[] = {
+	LTC4245_12VIN, LTC4245_5VIN, LTC4245_3VIN, LTC4245_VEEIN,
+	LTC4245_12VOUT, LTC4245_5VOUT, LTC4245_3VOUT, LTC4245_VEEOUT,
+};
+
+/* Map from current channel index to current register */
+
+static const s8 ltc4245_curr_regs[] = {
+	LTC4245_12VSENSE, LTC4245_5VSENSE, LTC4245_3VSENSE, LTC4245_VEESENSE,
+};
+
+static int ltc4245_read_curr(struct device *dev, u32 attr, int channel,
+			     long *val)
+{
+	struct ltc4245_data *data = ltc4245_update_device(dev);
+
+	switch (attr) {
+	case hwmon_curr_input:
+		*val = ltc4245_get_current(dev, ltc4245_curr_regs[channel]);
+		return 0;
+	case hwmon_curr_max_alarm:
+		*val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel + 4));
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ltc4245_read_in(struct device *dev, u32 attr, int channel, long *val)
+{
+	struct ltc4245_data *data = ltc4245_update_device(dev);
+
+	switch (attr) {
+	case hwmon_in_input:
+		if (channel < 8) {
+			*val = ltc4245_get_voltage(dev,
+						ltc4245_in_regs[channel]);
+		} else {
+			int regval = data->gpios[channel - 8];
+
+			if (regval < 0)
+				return regval;
+			*val = regval * 10;
+		}
+		return 0;
+	case hwmon_in_min_alarm:
+		if (channel < 4)
+			*val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel));
+		else
+			*val = !!(data->cregs[LTC4245_FAULT2] &
+				  BIT(channel - 4));
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ltc4245_read_power(struct device *dev, u32 attr, int channel,
+			      long *val)
+{
+	unsigned long curr;
+	long voltage;
+
+	switch (attr) {
+	case hwmon_power_input:
+		(void)ltc4245_update_device(dev);
+		curr = ltc4245_get_current(dev, ltc4245_curr_regs[channel]);
+		voltage = ltc4245_get_voltage(dev, ltc4245_in_regs[channel]);
+		*val = abs(curr * voltage);
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ltc4245_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+
+	switch (type) {
+	case hwmon_curr:
+		return ltc4245_read_curr(dev, attr, channel, val);
+	case hwmon_power:
+		return ltc4245_read_power(dev, attr, channel, val);
+	case hwmon_in:
+		return ltc4245_read_in(dev, attr, channel - 1, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static umode_t ltc4245_is_visible(const void *_data,
+				  enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	const struct ltc4245_data *data = _data;
+
+	switch (type) {
+	case hwmon_in:
+		if (channel == 0)
+			return 0;
+		switch (attr) {
+		case hwmon_in_input:
+			if (channel > 9 && !data->use_extra_gpios)
+				return 0;
+			return 0444;
+		case hwmon_in_min_alarm:
+			if (channel > 8)
+				return 0;
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_curr:
+		switch (attr) {
+		case hwmon_curr_input:
+		case hwmon_curr_max_alarm:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_power:
+		switch (attr) {
+		case hwmon_power_input:
+			return 0444;
+		default:
+			return 0;
+		}
+	default:
+		return 0;
+	}
+}
+
+static const struct hwmon_channel_info * const ltc4245_info[] = {
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT,
+			   HWMON_I_INPUT,
+			   HWMON_I_INPUT),
+	HWMON_CHANNEL_INFO(curr,
+			   HWMON_C_INPUT | HWMON_C_MAX_ALARM,
+			   HWMON_C_INPUT | HWMON_C_MAX_ALARM,
+			   HWMON_C_INPUT | HWMON_C_MAX_ALARM,
+			   HWMON_C_INPUT | HWMON_C_MAX_ALARM),
+	HWMON_CHANNEL_INFO(power,
+			   HWMON_P_INPUT,
+			   HWMON_P_INPUT,
+			   HWMON_P_INPUT,
+			   HWMON_P_INPUT),
+	NULL
+};
+
+static const struct hwmon_ops ltc4245_hwmon_ops = {
+	.is_visible = ltc4245_is_visible,
+	.read = ltc4245_read,
+};
+
+static const struct hwmon_chip_info ltc4245_chip_info = {
+	.ops = &ltc4245_hwmon_ops,
+	.info = ltc4245_info,
+};
+
+static bool ltc4245_use_extra_gpios(struct i2c_client *client)
+{
+	struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
+	struct device_node *np = client->dev.of_node;
+
+	/* prefer platform data */
+	if (pdata)
+		return pdata->use_extra_gpios;
+
+	/* fallback on OF */
+	if (of_property_read_bool(np, "ltc4245,use-extra-gpios"))
+		return true;
+
+	return false;
+}
+
+static int ltc4245_probe(struct i2c_client *client)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct ltc4245_data *data;
+	struct device *hwmon_dev;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	data->use_extra_gpios = ltc4245_use_extra_gpios(client);
+
+	/* Initialize the LTC4245 chip */
+	i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
+	i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
+
+	hwmon_dev = devm_hwmon_device_register_with_info(&client->dev,
+							 client->name, data,
+							 &ltc4245_chip_info,
+							 NULL);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id ltc4245_id[] = {
+	{ .name = "ltc4245" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ltc4245_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ltc4245_driver = {
+	.driver = {
+		.name	= "ltc4245",
+	},
+	.probe		= ltc4245_probe,
+	.id_table	= ltc4245_id,
+};
+
+module_i2c_driver(ltc4245_driver);
+
+MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
+MODULE_DESCRIPTION("LTC4245 driver");
+MODULE_LICENSE("GPL");