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, 231 insertions, 0 deletions

diff --git a/drivers/hwmon/ads7871.c b/drivers/hwmon/ads7871.c
new file mode 100644
index 000000000..d1cbff0e8
--- /dev/null
+++ b/drivers/hwmon/ads7871.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  ads7871 - driver for TI ADS7871 A/D converter
+ *
+ *  Copyright (c) 2010 Paul Thomas <pthomas8589@gmail.com>
+ *
+ *	You need to have something like this in struct spi_board_info
+ *	{
+ *		.modalias	= "ads7871",
+ *		.max_speed_hz	= 2*1000*1000,
+ *		.chip_select	= 0,
+ *		.bus_num	= 1,
+ *	},
+ */
+
+/*From figure 18 in the datasheet*/
+/*Register addresses*/
+#define REG_LS_BYTE	0 /*A/D Output Data, LS Byte*/
+#define REG_MS_BYTE	1 /*A/D Output Data, MS Byte*/
+#define REG_PGA_VALID	2 /*PGA Valid Register*/
+#define REG_AD_CONTROL	3 /*A/D Control Register*/
+#define REG_GAIN_MUX	4 /*Gain/Mux Register*/
+#define REG_IO_STATE	5 /*Digital I/O State Register*/
+#define REG_IO_CONTROL	6 /*Digital I/O Control Register*/
+#define REG_OSC_CONTROL	7 /*Rev/Oscillator Control Register*/
+#define REG_SER_CONTROL 24 /*Serial Interface Control Register*/
+#define REG_ID		31 /*ID Register*/
+
+/*
+ * From figure 17 in the datasheet
+ * These bits get ORed with the address to form
+ * the instruction byte
+ */
+/*Instruction Bit masks*/
+#define INST_MODE_BM	(1 << 7)
+#define INST_READ_BM	(1 << 6)
+#define INST_16BIT_BM	(1 << 5)
+
+/*From figure 18 in the datasheet*/
+/*bit masks for Rev/Oscillator Control Register*/
+#define MUX_CNV_BV	7
+#define MUX_CNV_BM	(1 << MUX_CNV_BV)
+#define MUX_M3_BM	(1 << 3) /*M3 selects single ended*/
+#define MUX_G_BV	4 /*allows for reg = (gain << MUX_G_BV) | ...*/
+
+/*From figure 18 in the datasheet*/
+/*bit masks for Rev/Oscillator Control Register*/
+#define OSC_OSCR_BM	(1 << 5)
+#define OSC_OSCE_BM	(1 << 4)
+#define OSC_REFE_BM	(1 << 3)
+#define OSC_BUFE_BM	(1 << 2)
+#define OSC_R2V_BM	(1 << 1)
+#define OSC_RBG_BM	(1 << 0)
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/spi/spi.h>
+#include <linux/hwmon.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+
+#define DEVICE_NAME	"ads7871"
+
+struct ads7871_data {
+	struct spi_device *spi;
+	u8 tx_buf[2] ____cacheline_aligned;
+};
+
+static umode_t ads7871_is_visible(const void *data,
+				  enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	if (type == hwmon_in && attr == hwmon_in_input)
+		return 0444;
+
+	return 0;
+}
+
+static int ads7871_read_reg8(struct spi_device *spi, int reg)
+{
+	int ret;
+	reg = reg | INST_READ_BM;
+	ret = spi_w8r8(spi, reg);
+	return ret;
+}
+
+static int ads7871_read_reg16(struct spi_device *spi, int reg)
+{
+	int ret;
+
+	reg = reg | INST_READ_BM | INST_16BIT_BM;
+	ret = spi_w8r16(spi, reg);
+	if (ret < 0)
+		return ret;
+
+	return le16_to_cpu((__force __le16)ret);
+}
+
+static int ads7871_write_reg8(struct ads7871_data *pdata, int reg, u8 val)
+{
+	pdata->tx_buf[0] = reg;
+	pdata->tx_buf[1] = val;
+
+	return spi_write(pdata->spi, pdata->tx_buf, 2);
+}
+
+static int ads7871_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	struct ads7871_data *pdata = dev_get_drvdata(dev);
+	struct spi_device *spi = pdata->spi;
+	int ret, raw_val, i = 0;
+	u8 mux_cnv;
+
+	if (type != hwmon_in || attr != hwmon_in_input)
+		return -EOPNOTSUPP;
+	/*
+	 * TODO: add support for conversions
+	 * other than single ended with a gain of 1
+	 */
+	/*MUX_M3_BM forces single ended*/
+	/*This is also where the gain of the PGA would be set*/
+	ret = ads7871_write_reg8(pdata, REG_GAIN_MUX,
+				 (MUX_CNV_BM | MUX_M3_BM | channel));
+	if (ret < 0)
+		return ret;
+
+	ret = ads7871_read_reg8(spi, REG_GAIN_MUX);
+	if (ret < 0)
+		return ret;
+
+	mux_cnv = ((ret & MUX_CNV_BM) >> MUX_CNV_BV);
+	/*
+	 * on 400MHz arm9 platform the conversion
+	 * is already done when we do this test
+	 */
+	while ((i < 2) && mux_cnv) {
+		i++;
+		ret = ads7871_read_reg8(spi, REG_GAIN_MUX);
+		if (ret < 0)
+			return ret;
+		mux_cnv = ((ret & MUX_CNV_BM) >> MUX_CNV_BV);
+		msleep_interruptible(1);
+	}
+
+	if (mux_cnv == 0) {
+		raw_val = ads7871_read_reg16(spi, REG_LS_BYTE);
+		if (raw_val < 0)
+			return raw_val;
+
+		/*
+		 * Use (s16) to ensure the sign bit is preserved during the shift.
+		 * Report millivolts (2.5V = 2500mV).
+		 */
+		*val = ((s16)raw_val >> 2) * 2500 / 8192;
+		return 0;
+	}
+
+	return -ETIMEDOUT;
+}
+
+static const struct hwmon_channel_info * const ads7871_info[] = {
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT,
+			   HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT, HWMON_I_INPUT),
+	NULL
+};
+
+static const struct hwmon_ops ads7871_hwmon_ops = {
+	.is_visible = ads7871_is_visible,
+	.read = ads7871_read,
+};
+
+static const struct hwmon_chip_info ads7871_chip_info = {
+	.ops = &ads7871_hwmon_ops,
+	.info = ads7871_info,
+};
+
+static int ads7871_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	int ret;
+	uint8_t val;
+	struct ads7871_data *pdata;
+	struct device *hwmon_dev;
+
+	/* Configure the SPI bus */
+	spi->mode = (SPI_MODE_0);
+	spi->bits_per_word = 8;
+	spi_setup(spi);
+
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	pdata->spi = spi;
+
+	ads7871_write_reg8(pdata, REG_SER_CONTROL, 0);
+	ads7871_write_reg8(pdata, REG_AD_CONTROL, 0);
+
+	val = (OSC_OSCR_BM | OSC_OSCE_BM | OSC_REFE_BM | OSC_BUFE_BM);
+	ads7871_write_reg8(pdata, REG_OSC_CONTROL, val);
+	ret = ads7871_read_reg8(spi, REG_OSC_CONTROL);
+
+	dev_dbg(dev, "REG_OSC_CONTROL write:%x, read:%x\n", val, ret);
+	/*
+	 * because there is no other error checking on an SPI bus
+	 * we need to make sure we really have a chip
+	 */
+	if (val != ret)
+		return -ENODEV;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, spi->modalias,
+							 pdata,
+							 &ads7871_chip_info,
+							 NULL);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static struct spi_driver ads7871_driver = {
+	.driver = {
+		.name = DEVICE_NAME,
+	},
+	.probe = ads7871_probe,
+};
+
+module_spi_driver(ads7871_driver);
+
+MODULE_AUTHOR("Paul Thomas <pthomas8589@gmail.com>");
+MODULE_DESCRIPTION("TI ADS7871 A/D driver");
+MODULE_LICENSE("GPL");