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, 402 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-tegra.c b/drivers/rtc/rtc-tegra.c
new file mode 100644
index 000000000..f16405c39
--- /dev/null
+++ b/drivers/rtc/rtc-tegra.c
@@ -0,0 +1,402 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * An RTC driver for the NVIDIA Tegra 200 series internal RTC.
+ *
+ * Copyright (c) 2010-2019, NVIDIA Corporation.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+
+/* Set to 1 = busy every eight 32 kHz clocks during copy of sec+msec to AHB. */
+#define TEGRA_RTC_REG_BUSY			0x004
+#define TEGRA_RTC_REG_SECONDS			0x008
+/* When msec is read, the seconds are buffered into shadow seconds. */
+#define TEGRA_RTC_REG_SHADOW_SECONDS		0x00c
+#define TEGRA_RTC_REG_MILLI_SECONDS		0x010
+#define TEGRA_RTC_REG_SECONDS_ALARM0		0x014
+#define TEGRA_RTC_REG_SECONDS_ALARM1		0x018
+#define TEGRA_RTC_REG_MILLI_SECONDS_ALARM0	0x01c
+#define TEGRA_RTC_REG_INTR_MASK			0x028
+/* write 1 bits to clear status bits */
+#define TEGRA_RTC_REG_INTR_STATUS		0x02c
+
+/* bits in INTR_MASK */
+#define TEGRA_RTC_INTR_MASK_MSEC_CDN_ALARM	(1<<4)
+#define TEGRA_RTC_INTR_MASK_SEC_CDN_ALARM	(1<<3)
+#define TEGRA_RTC_INTR_MASK_MSEC_ALARM		(1<<2)
+#define TEGRA_RTC_INTR_MASK_SEC_ALARM1		(1<<1)
+#define TEGRA_RTC_INTR_MASK_SEC_ALARM0		(1<<0)
+
+/* bits in INTR_STATUS */
+#define TEGRA_RTC_INTR_STATUS_MSEC_CDN_ALARM	(1<<4)
+#define TEGRA_RTC_INTR_STATUS_SEC_CDN_ALARM	(1<<3)
+#define TEGRA_RTC_INTR_STATUS_MSEC_ALARM	(1<<2)
+#define TEGRA_RTC_INTR_STATUS_SEC_ALARM1	(1<<1)
+#define TEGRA_RTC_INTR_STATUS_SEC_ALARM0	(1<<0)
+
+struct tegra_rtc_info {
+	struct platform_device *pdev;
+	struct rtc_device *rtc;
+	void __iomem *base; /* NULL if not initialized */
+	struct clk *clk;
+	int irq; /* alarm and periodic IRQ */
+	spinlock_t lock;
+};
+
+/*
+ * RTC hardware is busy when it is updating its values over AHB once every
+ * eight 32 kHz clocks (~250 us). Outside of these updates the CPU is free to
+ * write. CPU is always free to read.
+ */
+static inline u32 tegra_rtc_check_busy(struct tegra_rtc_info *info)
+{
+	return readl(info->base + TEGRA_RTC_REG_BUSY) & 1;
+}
+
+/*
+ * Wait for hardware to be ready for writing. This function tries to maximize
+ * the amount of time before the next update. It does this by waiting for the
+ * RTC to become busy with its periodic update, then returning once the RTC
+ * first becomes not busy.
+ *
+ * This periodic update (where the seconds and milliseconds are copied to the
+ * AHB side) occurs every eight 32 kHz clocks (~250 us). The behavior of this
+ * function allows us to make some assumptions without introducing a race,
+ * because 250 us is plenty of time to read/write a value.
+ */
+static int tegra_rtc_wait_while_busy(struct device *dev)
+{
+	struct tegra_rtc_info *info = dev_get_drvdata(dev);
+	int retries = 500; /* ~490 us is the worst case, ~250 us is best */
+
+	/*
+	 * First wait for the RTC to become busy. This is when it posts its
+	 * updated seconds+msec registers to AHB side.
+	 */
+	while (tegra_rtc_check_busy(info)) {
+		if (!retries--)
+			goto retry_failed;
+
+		udelay(1);
+	}
+
+	/* now we have about 250 us to manipulate registers */
+	return 0;
+
+retry_failed:
+	dev_err(dev, "write failed: retry count exceeded\n");
+	return -ETIMEDOUT;
+}
+
+static int tegra_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct tegra_rtc_info *info = dev_get_drvdata(dev);
+	unsigned long flags;
+	u32 sec;
+
+	/*
+	 * RTC hardware copies seconds to shadow seconds when a read of
+	 * milliseconds occurs. use a lock to keep other threads out.
+	 */
+	spin_lock_irqsave(&info->lock, flags);
+
+	readl(info->base + TEGRA_RTC_REG_MILLI_SECONDS);
+	sec = readl(info->base + TEGRA_RTC_REG_SHADOW_SECONDS);
+
+	spin_unlock_irqrestore(&info->lock, flags);
+
+	rtc_time64_to_tm(sec, tm);
+
+	dev_vdbg(dev, "time read as %u, %ptR\n", sec, tm);
+
+	return 0;
+}
+
+static int tegra_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct tegra_rtc_info *info = dev_get_drvdata(dev);
+	u32 sec;
+	int ret;
+
+	/* convert tm to seconds */
+	sec = rtc_tm_to_time64(tm);
+
+	dev_vdbg(dev, "time set to %u, %ptR\n", sec, tm);
+
+	/* seconds only written if wait succeeded */
+	ret = tegra_rtc_wait_while_busy(dev);
+	if (!ret)
+		writel(sec, info->base + TEGRA_RTC_REG_SECONDS);
+
+	dev_vdbg(dev, "time read back as %d\n",
+		 readl(info->base + TEGRA_RTC_REG_SECONDS));
+
+	return ret;
+}
+
+static int tegra_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	struct tegra_rtc_info *info = dev_get_drvdata(dev);
+	u32 sec, value;
+
+	sec = readl(info->base + TEGRA_RTC_REG_SECONDS_ALARM0);
+
+	if (sec == 0) {
+		/* alarm is disabled */
+		alarm->enabled = 0;
+	} else {
+		/* alarm is enabled */
+		alarm->enabled = 1;
+		rtc_time64_to_tm(sec, &alarm->time);
+	}
+
+	value = readl(info->base + TEGRA_RTC_REG_INTR_STATUS);
+	alarm->pending = (value & TEGRA_RTC_INTR_STATUS_SEC_ALARM0) != 0;
+
+	return 0;
+}
+
+static int tegra_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct tegra_rtc_info *info = dev_get_drvdata(dev);
+	unsigned long flags;
+	u32 status;
+
+	tegra_rtc_wait_while_busy(dev);
+	spin_lock_irqsave(&info->lock, flags);
+
+	/* read the original value, and OR in the flag */
+	status = readl(info->base + TEGRA_RTC_REG_INTR_MASK);
+	if (enabled)
+		status |= TEGRA_RTC_INTR_MASK_SEC_ALARM0; /* set it */
+	else
+		status &= ~TEGRA_RTC_INTR_MASK_SEC_ALARM0; /* clear it */
+
+	writel(status, info->base + TEGRA_RTC_REG_INTR_MASK);
+
+	spin_unlock_irqrestore(&info->lock, flags);
+
+	return 0;
+}
+
+static int tegra_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	struct tegra_rtc_info *info = dev_get_drvdata(dev);
+	u32 sec;
+
+	if (alarm->enabled)
+		sec = rtc_tm_to_time64(&alarm->time);
+	else
+		sec = 0;
+
+	tegra_rtc_wait_while_busy(dev);
+	writel(sec, info->base + TEGRA_RTC_REG_SECONDS_ALARM0);
+	dev_vdbg(dev, "alarm read back as %d\n",
+		 readl(info->base + TEGRA_RTC_REG_SECONDS_ALARM0));
+
+	/* if successfully written and alarm is enabled ... */
+	if (sec) {
+		tegra_rtc_alarm_irq_enable(dev, 1);
+		dev_vdbg(dev, "alarm set as %u, %ptR\n", sec, &alarm->time);
+	} else {
+		/* disable alarm if 0 or write error */
+		dev_vdbg(dev, "alarm disabled\n");
+		tegra_rtc_alarm_irq_enable(dev, 0);
+	}
+
+	return 0;
+}
+
+static int tegra_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+	if (!dev || !dev->driver)
+		return 0;
+
+	seq_printf(seq, "name\t\t: %s\n", dev_name(dev));
+
+	return 0;
+}
+
+static irqreturn_t tegra_rtc_irq_handler(int irq, void *data)
+{
+	struct device *dev = data;
+	struct tegra_rtc_info *info = dev_get_drvdata(dev);
+	unsigned long events = 0;
+	u32 status;
+
+	status = readl(info->base + TEGRA_RTC_REG_INTR_STATUS);
+	if (status) {
+		/* clear the interrupt masks and status on any IRQ */
+		tegra_rtc_wait_while_busy(dev);
+
+		spin_lock(&info->lock);
+		writel(0, info->base + TEGRA_RTC_REG_INTR_MASK);
+		writel(status, info->base + TEGRA_RTC_REG_INTR_STATUS);
+		spin_unlock(&info->lock);
+	}
+
+	/* check if alarm */
+	if (status & TEGRA_RTC_INTR_STATUS_SEC_ALARM0)
+		events |= RTC_IRQF | RTC_AF;
+
+	/* check if periodic */
+	if (status & TEGRA_RTC_INTR_STATUS_SEC_CDN_ALARM)
+		events |= RTC_IRQF | RTC_PF;
+
+	rtc_update_irq(info->rtc, 1, events);
+
+	return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops tegra_rtc_ops = {
+	.read_time = tegra_rtc_read_time,
+	.set_time = tegra_rtc_set_time,
+	.read_alarm = tegra_rtc_read_alarm,
+	.set_alarm = tegra_rtc_set_alarm,
+	.proc = tegra_rtc_proc,
+	.alarm_irq_enable = tegra_rtc_alarm_irq_enable,
+};
+
+static const struct of_device_id tegra_rtc_dt_match[] = {
+	{ .compatible = "nvidia,tegra20-rtc", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, tegra_rtc_dt_match);
+
+static const struct acpi_device_id tegra_rtc_acpi_match[] = {
+	{ "NVDA0280" },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, tegra_rtc_acpi_match);
+
+static int tegra_rtc_probe(struct platform_device *pdev)
+{
+	struct tegra_rtc_info *info;
+	int ret;
+
+	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(info->base))
+		return PTR_ERR(info->base);
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret <= 0)
+		return ret;
+
+	info->irq = ret;
+
+	info->rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(info->rtc))
+		return PTR_ERR(info->rtc);
+
+	info->rtc->ops = &tegra_rtc_ops;
+	info->rtc->range_max = U32_MAX;
+
+	if (dev_of_node(&pdev->dev)) {
+		info->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+		if (IS_ERR(info->clk))
+			return PTR_ERR(info->clk);
+	}
+
+	/* set context info */
+	info->pdev = pdev;
+	spin_lock_init(&info->lock);
+
+	platform_set_drvdata(pdev, info);
+
+	/* clear out the hardware */
+	writel(0, info->base + TEGRA_RTC_REG_SECONDS_ALARM0);
+	writel(0xffffffff, info->base + TEGRA_RTC_REG_INTR_STATUS);
+	writel(0, info->base + TEGRA_RTC_REG_INTR_MASK);
+
+	device_init_wakeup(&pdev->dev, true);
+
+	ret = devm_request_irq(&pdev->dev, info->irq, tegra_rtc_irq_handler,
+			       IRQF_TRIGGER_HIGH, dev_name(&pdev->dev),
+			       &pdev->dev);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "failed to request interrupt\n");
+
+	ret = devm_rtc_register_device(info->rtc);
+	if (ret)
+		return ret;
+
+	dev_notice(&pdev->dev, "Tegra internal Real Time Clock\n");
+
+	return 0;
+}
+
+static int tegra_rtc_suspend(struct device *dev)
+{
+	struct tegra_rtc_info *info = dev_get_drvdata(dev);
+
+	tegra_rtc_wait_while_busy(dev);
+
+	/* only use ALARM0 as a wake source */
+	writel(0xffffffff, info->base + TEGRA_RTC_REG_INTR_STATUS);
+	writel(TEGRA_RTC_INTR_STATUS_SEC_ALARM0,
+	       info->base + TEGRA_RTC_REG_INTR_MASK);
+
+	dev_vdbg(dev, "alarm sec = %d\n",
+		 readl(info->base + TEGRA_RTC_REG_SECONDS_ALARM0));
+
+	dev_vdbg(dev, "Suspend (device_may_wakeup=%d) IRQ:%d\n",
+		 device_may_wakeup(dev), info->irq);
+
+	/* leave the alarms on as a wake source */
+	if (device_may_wakeup(dev))
+		enable_irq_wake(info->irq);
+
+	return 0;
+}
+
+static int tegra_rtc_resume(struct device *dev)
+{
+	struct tegra_rtc_info *info = dev_get_drvdata(dev);
+
+	dev_vdbg(dev, "Resume (device_may_wakeup=%d)\n",
+		 device_may_wakeup(dev));
+
+	/* alarms were left on as a wake source, turn them off */
+	if (device_may_wakeup(dev))
+		disable_irq_wake(info->irq);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(tegra_rtc_pm_ops, tegra_rtc_suspend, tegra_rtc_resume);
+
+static void tegra_rtc_shutdown(struct platform_device *pdev)
+{
+	dev_vdbg(&pdev->dev, "disabling interrupts\n");
+	tegra_rtc_alarm_irq_enable(&pdev->dev, 0);
+}
+
+static struct platform_driver tegra_rtc_driver = {
+	.probe = tegra_rtc_probe,
+	.shutdown = tegra_rtc_shutdown,
+	.driver = {
+		.name = "tegra_rtc",
+		.of_match_table = tegra_rtc_dt_match,
+		.acpi_match_table = tegra_rtc_acpi_match,
+		.pm = pm_sleep_ptr(&tegra_rtc_pm_ops),
+	},
+};
+module_platform_driver(tegra_rtc_driver);
+
+MODULE_AUTHOR("Jon Mayo <jmayo@nvidia.com>");
+MODULE_DESCRIPTION("driver for Tegra internal RTC");
+MODULE_LICENSE("GPL");