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, 452 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-mcp795.c b/drivers/rtc/rtc-mcp795.c
new file mode 100644
index 000000000..e12f0f806
--- /dev/null
+++ b/drivers/rtc/rtc-mcp795.c
@@ -0,0 +1,452 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SPI Driver for Microchip MCP795 RTC
+ *
+ * Copyright (C) Josef Gajdusek <atx@atx.name>
+ *
+ * based on other Linux RTC drivers
+ *
+ * Device datasheet:
+ * https://ww1.microchip.com/downloads/en/DeviceDoc/22280A.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/printk.h>
+#include <linux/spi/spi.h>
+#include <linux/rtc.h>
+#include <linux/of.h>
+#include <linux/bcd.h>
+#include <linux/delay.h>
+
+/* MCP795 Instructions, see datasheet table 3-1 */
+#define MCP795_EEREAD	0x03
+#define MCP795_EEWRITE	0x02
+#define MCP795_EEWRDI	0x04
+#define MCP795_EEWREN	0x06
+#define MCP795_SRREAD	0x05
+#define MCP795_SRWRITE	0x01
+#define MCP795_READ	0x13
+#define MCP795_WRITE	0x12
+#define MCP795_UNLOCK	0x14
+#define MCP795_IDWRITE	0x32
+#define MCP795_IDREAD	0x33
+#define MCP795_CLRWDT	0x44
+#define MCP795_CLRRAM	0x54
+
+/* MCP795 RTCC registers, see datasheet table 4-1 */
+#define MCP795_REG_SECONDS	0x01
+#define MCP795_REG_DAY		0x04
+#define MCP795_REG_MONTH	0x06
+#define MCP795_REG_CONTROL	0x08
+#define MCP795_REG_ALM0_SECONDS	0x0C
+#define MCP795_REG_ALM0_DAY	0x0F
+
+#define MCP795_ST_BIT		BIT(7)
+#define MCP795_24_BIT		BIT(6)
+#define MCP795_LP_BIT		BIT(5)
+#define MCP795_EXTOSC_BIT	BIT(3)
+#define MCP795_OSCON_BIT	BIT(5)
+#define MCP795_ALM0_BIT		BIT(4)
+#define MCP795_ALM1_BIT		BIT(5)
+#define MCP795_ALM0IF_BIT	BIT(3)
+#define MCP795_ALM0C0_BIT	BIT(4)
+#define MCP795_ALM0C1_BIT	BIT(5)
+#define MCP795_ALM0C2_BIT	BIT(6)
+
+#define SEC_PER_DAY		(24 * 60 * 60)
+
+static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	int ret;
+	u8 tx[2];
+
+	tx[0] = MCP795_READ;
+	tx[1] = addr;
+	ret = spi_write_then_read(spi, tx, sizeof(tx), buf, count);
+
+	if (ret)
+		dev_err(dev, "Failed reading %d bytes from address %x.\n",
+					count, addr);
+
+	return ret;
+}
+
+static int mcp795_rtcc_write(struct device *dev, u8 addr, u8 *data, u8 count)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	int ret;
+	u8 tx[257];
+
+	tx[0] = MCP795_WRITE;
+	tx[1] = addr;
+	memcpy(&tx[2], data, count);
+
+	ret = spi_write(spi, tx, 2 + count);
+
+	if (ret)
+		dev_err(dev, "Failed to write %d bytes to address %x.\n",
+					count, addr);
+
+	return ret;
+}
+
+static int mcp795_rtcc_set_bits(struct device *dev, u8 addr, u8 mask, u8 state)
+{
+	int ret;
+	u8 tmp;
+
+	ret = mcp795_rtcc_read(dev, addr, &tmp, 1);
+	if (ret)
+		return ret;
+
+	if ((tmp & mask) != state) {
+		tmp = (tmp & ~mask) | state;
+		ret = mcp795_rtcc_write(dev, addr, &tmp, 1);
+	}
+
+	return ret;
+}
+
+static int mcp795_stop_oscillator(struct device *dev, bool *extosc)
+{
+	int retries = 5;
+	int ret;
+	u8 data;
+
+	ret = mcp795_rtcc_set_bits(dev, MCP795_REG_SECONDS, MCP795_ST_BIT, 0);
+	if (ret)
+		return ret;
+	ret = mcp795_rtcc_read(dev, MCP795_REG_CONTROL, &data, 1);
+	if (ret)
+		return ret;
+	*extosc = !!(data & MCP795_EXTOSC_BIT);
+	ret = mcp795_rtcc_set_bits(
+				dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, 0);
+	if (ret)
+		return ret;
+	/* wait for the OSCON bit to clear */
+	do {
+		usleep_range(700, 800);
+		ret = mcp795_rtcc_read(dev, MCP795_REG_DAY, &data, 1);
+		if (ret)
+			break;
+		if (!(data & MCP795_OSCON_BIT))
+			break;
+
+	} while (--retries);
+
+	return !retries ? -EIO : ret;
+}
+
+static int mcp795_start_oscillator(struct device *dev, bool *extosc)
+{
+	if (extosc) {
+		u8 data = *extosc ? MCP795_EXTOSC_BIT : 0;
+		int ret;
+
+		ret = mcp795_rtcc_set_bits(
+			dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, data);
+		if (ret)
+			return ret;
+	}
+	return mcp795_rtcc_set_bits(
+			dev, MCP795_REG_SECONDS, MCP795_ST_BIT, MCP795_ST_BIT);
+}
+
+/* Enable or disable Alarm 0 in RTC */
+static int mcp795_update_alarm(struct device *dev, bool enable)
+{
+	int ret;
+
+	dev_dbg(dev, "%s alarm\n", enable ? "Enable" : "Disable");
+
+	if (enable) {
+		/* clear ALM0IF (Alarm 0 Interrupt Flag) bit */
+		ret = mcp795_rtcc_set_bits(dev, MCP795_REG_ALM0_DAY,
+					MCP795_ALM0IF_BIT, 0);
+		if (ret)
+			return ret;
+		/* enable alarm 0 */
+		ret = mcp795_rtcc_set_bits(dev, MCP795_REG_CONTROL,
+					MCP795_ALM0_BIT, MCP795_ALM0_BIT);
+	} else {
+		/* disable alarm 0 and alarm 1 */
+		ret = mcp795_rtcc_set_bits(dev, MCP795_REG_CONTROL,
+					MCP795_ALM0_BIT | MCP795_ALM1_BIT, 0);
+	}
+	return ret;
+}
+
+static int mcp795_set_time(struct device *dev, struct rtc_time *tim)
+{
+	int ret;
+	u8 data[7];
+	bool extosc;
+
+	/* Stop RTC and store current value of EXTOSC bit */
+	ret = mcp795_stop_oscillator(dev, &extosc);
+	if (ret)
+		return ret;
+
+	/* Read first, so we can leave config bits untouched */
+	ret = mcp795_rtcc_read(dev, MCP795_REG_SECONDS, data, sizeof(data));
+
+	if (ret)
+		return ret;
+
+	data[0] = (data[0] & 0x80) | bin2bcd(tim->tm_sec);
+	data[1] = (data[1] & 0x80) | bin2bcd(tim->tm_min);
+	data[2] = bin2bcd(tim->tm_hour);
+	data[3] = (data[3] & 0xF8) | bin2bcd(tim->tm_wday + 1);
+	data[4] = bin2bcd(tim->tm_mday);
+	data[5] = (data[5] & MCP795_LP_BIT) | bin2bcd(tim->tm_mon + 1);
+
+	if (tim->tm_year > 100)
+		tim->tm_year -= 100;
+
+	data[6] = bin2bcd(tim->tm_year);
+
+	/* Always write the date and month using a separate Write command.
+	 * This is a workaround for a know silicon issue that some combinations
+	 * of date and month values may result in the date being reset to 1.
+	 */
+	ret = mcp795_rtcc_write(dev, MCP795_REG_SECONDS, data, 5);
+	if (ret)
+		return ret;
+
+	ret = mcp795_rtcc_write(dev, MCP795_REG_MONTH, &data[5], 2);
+	if (ret)
+		return ret;
+
+	/* Start back RTC and restore previous value of EXTOSC bit.
+	 * There is no need to clear EXTOSC bit when the previous value was 0
+	 * because it was already cleared when stopping the RTC oscillator.
+	 */
+	ret = mcp795_start_oscillator(dev, extosc ? &extosc : NULL);
+	if (ret)
+		return ret;
+
+	dev_dbg(dev, "Set mcp795: %ptR\n", tim);
+
+	return 0;
+}
+
+static int mcp795_read_time(struct device *dev, struct rtc_time *tim)
+{
+	int ret;
+	u8 data[7];
+
+	ret = mcp795_rtcc_read(dev, MCP795_REG_SECONDS, data, sizeof(data));
+
+	if (ret)
+		return ret;
+
+	tim->tm_sec	= bcd2bin(data[0] & 0x7F);
+	tim->tm_min	= bcd2bin(data[1] & 0x7F);
+	tim->tm_hour	= bcd2bin(data[2] & 0x3F);
+	tim->tm_wday	= bcd2bin(data[3] & 0x07) - 1;
+	tim->tm_mday	= bcd2bin(data[4] & 0x3F);
+	tim->tm_mon	= bcd2bin(data[5] & 0x1F) - 1;
+	tim->tm_year	= bcd2bin(data[6]) + 100; /* Assume we are in 20xx */
+
+	dev_dbg(dev, "Read from mcp795: %ptR\n", tim);
+
+	return 0;
+}
+
+static int mcp795_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+	struct rtc_time now_tm;
+	time64_t now;
+	time64_t later;
+	u8 tmp[6];
+	int ret;
+
+	/* Read current time from RTC hardware */
+	ret = mcp795_read_time(dev, &now_tm);
+	if (ret)
+		return ret;
+	/* Get the number of seconds since 1970 */
+	now = rtc_tm_to_time64(&now_tm);
+	later = rtc_tm_to_time64(&alm->time);
+	if (later <= now)
+		return -EINVAL;
+	/* make sure alarm fires within the next one year */
+	if ((later - now) >=
+		(SEC_PER_DAY * (365 + is_leap_year(alm->time.tm_year))))
+		return -EDOM;
+	/* disable alarm */
+	ret = mcp795_update_alarm(dev, false);
+	if (ret)
+		return ret;
+	/* Read registers, so we can leave configuration bits untouched */
+	ret = mcp795_rtcc_read(dev, MCP795_REG_ALM0_SECONDS, tmp, sizeof(tmp));
+	if (ret)
+		return ret;
+
+	alm->time.tm_year	= -1;
+	alm->time.tm_isdst	= -1;
+	alm->time.tm_yday	= -1;
+
+	tmp[0] = (tmp[0] & 0x80) | bin2bcd(alm->time.tm_sec);
+	tmp[1] = (tmp[1] & 0x80) | bin2bcd(alm->time.tm_min);
+	tmp[2] = (tmp[2] & 0xE0) | bin2bcd(alm->time.tm_hour);
+	tmp[3] = (tmp[3] & 0x80) | bin2bcd(alm->time.tm_wday + 1);
+	/* set alarm match: seconds, minutes, hour, day, date and month */
+	tmp[3] |= (MCP795_ALM0C2_BIT | MCP795_ALM0C1_BIT | MCP795_ALM0C0_BIT);
+	tmp[4] = (tmp[4] & 0xC0) | bin2bcd(alm->time.tm_mday);
+	tmp[5] = (tmp[5] & 0xE0) | bin2bcd(alm->time.tm_mon + 1);
+
+	ret = mcp795_rtcc_write(dev, MCP795_REG_ALM0_SECONDS, tmp, sizeof(tmp));
+	if (ret)
+		return ret;
+
+	/* enable alarm if requested */
+	if (alm->enabled) {
+		ret = mcp795_update_alarm(dev, true);
+		if (ret)
+			return ret;
+		dev_dbg(dev, "Alarm IRQ armed\n");
+	}
+	dev_dbg(dev, "Set alarm: %ptRdr(%d) %ptRt\n",
+		&alm->time, alm->time.tm_wday, &alm->time);
+	return 0;
+}
+
+static int mcp795_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+	u8 data[6];
+	int ret;
+
+	ret = mcp795_rtcc_read(
+			dev, MCP795_REG_ALM0_SECONDS, data, sizeof(data));
+	if (ret)
+		return ret;
+
+	alm->time.tm_sec	= bcd2bin(data[0] & 0x7F);
+	alm->time.tm_min	= bcd2bin(data[1] & 0x7F);
+	alm->time.tm_hour	= bcd2bin(data[2] & 0x1F);
+	alm->time.tm_wday	= bcd2bin(data[3] & 0x07) - 1;
+	alm->time.tm_mday	= bcd2bin(data[4] & 0x3F);
+	alm->time.tm_mon	= bcd2bin(data[5] & 0x1F) - 1;
+	alm->time.tm_year	= -1;
+	alm->time.tm_isdst	= -1;
+	alm->time.tm_yday	= -1;
+
+	dev_dbg(dev, "Read alarm: %ptRdr(%d) %ptRt\n",
+		&alm->time, alm->time.tm_wday, &alm->time);
+	return 0;
+}
+
+static int mcp795_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	return mcp795_update_alarm(dev, !!enabled);
+}
+
+static irqreturn_t mcp795_irq(int irq, void *data)
+{
+	struct spi_device *spi = data;
+	struct rtc_device *rtc = spi_get_drvdata(spi);
+	int ret;
+
+	rtc_lock(rtc);
+
+	/* Disable alarm.
+	 * There is no need to clear ALM0IF (Alarm 0 Interrupt Flag) bit,
+	 * because it is done every time when alarm is enabled.
+	 */
+	ret = mcp795_update_alarm(&spi->dev, false);
+	if (ret)
+		dev_err(&spi->dev,
+			"Failed to disable alarm in IRQ (ret=%d)\n", ret);
+	rtc_update_irq(rtc, 1, RTC_AF | RTC_IRQF);
+
+	rtc_unlock(rtc);
+
+	return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops mcp795_rtc_ops = {
+		.read_time = mcp795_read_time,
+		.set_time = mcp795_set_time,
+		.read_alarm = mcp795_read_alarm,
+		.set_alarm = mcp795_set_alarm,
+		.alarm_irq_enable = mcp795_alarm_irq_enable
+};
+
+static int mcp795_probe(struct spi_device *spi)
+{
+	struct rtc_device *rtc;
+	int ret;
+
+	spi->mode = SPI_MODE_0;
+	spi->bits_per_word = 8;
+	ret = spi_setup(spi);
+	if (ret) {
+		dev_err(&spi->dev, "Unable to setup SPI\n");
+		return ret;
+	}
+
+	/* Start the oscillator but don't set the value of EXTOSC bit */
+	mcp795_start_oscillator(&spi->dev, NULL);
+	/* Clear the 12 hour mode flag*/
+	mcp795_rtcc_set_bits(&spi->dev, 0x03, MCP795_24_BIT, 0);
+
+	rtc = devm_rtc_device_register(&spi->dev, "rtc-mcp795",
+					&mcp795_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	spi_set_drvdata(spi, rtc);
+
+	if (spi->irq > 0) {
+		dev_dbg(&spi->dev, "Alarm support enabled\n");
+
+		/* Clear any pending alarm (ALM0IF bit) before requesting
+		 * the interrupt.
+		 */
+		mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_ALM0_DAY,
+					MCP795_ALM0IF_BIT, 0);
+		ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
+				mcp795_irq, IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+				dev_name(&rtc->dev), spi);
+		if (ret)
+			dev_err(&spi->dev, "Failed to request IRQ: %d: %d\n",
+						spi->irq, ret);
+		else
+			device_init_wakeup(&spi->dev, true);
+	}
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id mcp795_of_match[] = {
+	{ .compatible = "maxim,mcp795" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mcp795_of_match);
+#endif
+
+static const struct spi_device_id mcp795_spi_ids[] = {
+	{ .name = "mcp795" },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, mcp795_spi_ids);
+
+static struct spi_driver mcp795_driver = {
+		.driver = {
+				.name = "rtc-mcp795",
+				.of_match_table = of_match_ptr(mcp795_of_match),
+		},
+		.probe = mcp795_probe,
+		.id_table = mcp795_spi_ids,
+};
+
+module_spi_driver(mcp795_driver);
+
+MODULE_DESCRIPTION("MCP795 RTC SPI Driver");
+MODULE_AUTHOR("Josef Gajdusek <atx@atx.name>");
+MODULE_LICENSE("GPL");