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, 546 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
new file mode 100644
index 000000000..38991cca5
--- /dev/null
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -0,0 +1,546 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * "RTT as Real Time Clock" driver for AT91SAM9 SoC family
+ *
+ * (C) 2007 Michel Benoit
+ *
+ * Based on rtc-at91rm9200.c by Rick Bronson
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/ioctl.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+#include <linux/time.h>
+
+/*
+ * This driver uses two configurable hardware resources that live in the
+ * AT91SAM9 backup power domain (intended to be powered at all times)
+ * to implement the Real Time Clock interfaces
+ *
+ *  - A "Real-time Timer" (RTT) counts up in seconds from a base time.
+ *    We can't assign the counter value (CRTV) ... but we can reset it.
+ *
+ *  - One of the "General Purpose Backup Registers" (GPBRs) holds the
+ *    base time, normally an offset from the beginning of the POSIX
+ *    epoch (1970-Jan-1 00:00:00 UTC).  Some systems also include the
+ *    local timezone's offset.
+ *
+ * The RTC's value is the RTT counter plus that offset.  The RTC's alarm
+ * is likewise a base (ALMV) plus that offset.
+ *
+ * Not all RTTs will be used as RTCs; some systems have multiple RTTs to
+ * choose from, or a "real" RTC module.  All systems have multiple GPBR
+ * registers available, likewise usable for more than "RTC" support.
+ */
+
+#define AT91_RTT_MR		0x00		/* Real-time Mode Register */
+#define AT91_RTT_RTPRES		(0xffff << 0)	/* Timer Prescaler Value */
+#define AT91_RTT_ALMIEN		BIT(16)		/* Alarm Interrupt Enable */
+#define AT91_RTT_RTTINCIEN	BIT(17)		/* Increment Interrupt Enable */
+#define AT91_RTT_RTTRST		BIT(18)		/* Timer Restart */
+
+#define AT91_RTT_AR		0x04		/* Real-time Alarm Register */
+#define AT91_RTT_ALMV		(0xffffffff)	/* Alarm Value */
+
+#define AT91_RTT_VR		0x08		/* Real-time Value Register */
+#define AT91_RTT_CRTV		(0xffffffff)	/* Current Real-time Value */
+
+#define AT91_RTT_SR		0x0c		/* Real-time Status Register */
+#define AT91_RTT_ALMS		BIT(0)		/* Alarm Status */
+#define AT91_RTT_RTTINC		BIT(1)		/* Timer Increment */
+
+/*
+ * We store ALARM_DISABLED in ALMV to record that no alarm is set.
+ * It's also the reset value for that field.
+ */
+#define ALARM_DISABLED	((u32)~0)
+
+struct sam9_rtc {
+	void __iomem		*rtt;
+	struct rtc_device	*rtcdev;
+	u32			imr;
+	struct regmap		*gpbr;
+	unsigned int		gpbr_offset;
+	int			irq;
+	struct clk		*sclk;
+	bool			suspended;
+	unsigned long		events;
+	spinlock_t		lock;
+};
+
+#define rtt_readl(rtc, field) \
+	readl((rtc)->rtt + AT91_RTT_ ## field)
+#define rtt_writel(rtc, field, val) \
+	writel((val), (rtc)->rtt + AT91_RTT_ ## field)
+
+static inline unsigned int gpbr_readl(struct sam9_rtc *rtc)
+{
+	unsigned int val;
+
+	regmap_read(rtc->gpbr, rtc->gpbr_offset, &val);
+
+	return val;
+}
+
+static inline void gpbr_writel(struct sam9_rtc *rtc, unsigned int val)
+{
+	regmap_write(rtc->gpbr, rtc->gpbr_offset, val);
+}
+
+/*
+ * Read current time and date in RTC
+ */
+static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
+{
+	struct sam9_rtc *rtc = dev_get_drvdata(dev);
+	u32 secs, secs2;
+	u32 offset;
+
+	/* read current time offset */
+	offset = gpbr_readl(rtc);
+	if (offset == 0)
+		return -EILSEQ;
+
+	/* reread the counter to help sync the two clock domains */
+	secs = rtt_readl(rtc, VR);
+	secs2 = rtt_readl(rtc, VR);
+	if (secs != secs2)
+		secs = rtt_readl(rtc, VR);
+
+	rtc_time64_to_tm(offset + secs, tm);
+
+	dev_dbg(dev, "%s: %ptR\n", __func__, tm);
+
+	return 0;
+}
+
+/*
+ * Set current time and date in RTC
+ */
+static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
+{
+	struct sam9_rtc *rtc = dev_get_drvdata(dev);
+	u32 offset, alarm, mr;
+	unsigned long secs;
+
+	dev_dbg(dev, "%s: %ptR\n", __func__, tm);
+
+	secs = rtc_tm_to_time64(tm);
+
+	mr = rtt_readl(rtc, MR);
+
+	/* disable interrupts */
+	rtt_writel(rtc, MR, mr & ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN));
+
+	/* read current time offset */
+	offset = gpbr_readl(rtc);
+
+	/* store the new base time in a battery backup register */
+	secs += 1;
+	gpbr_writel(rtc, secs);
+
+	/* adjust the alarm time for the new base */
+	alarm = rtt_readl(rtc, AR);
+	if (alarm != ALARM_DISABLED) {
+		if (offset > secs) {
+			/* time jumped backwards, increase time until alarm */
+			alarm += (offset - secs);
+		} else if ((alarm + offset) > secs) {
+			/* time jumped forwards, decrease time until alarm */
+			alarm -= (secs - offset);
+		} else {
+			/* time jumped past the alarm, disable alarm */
+			alarm = ALARM_DISABLED;
+			mr &= ~AT91_RTT_ALMIEN;
+		}
+		rtt_writel(rtc, AR, alarm);
+	}
+
+	/* reset the timer, and re-enable interrupts */
+	rtt_writel(rtc, MR, mr | AT91_RTT_RTTRST);
+
+	return 0;
+}
+
+static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct sam9_rtc *rtc = dev_get_drvdata(dev);
+	struct rtc_time *tm = &alrm->time;
+	u32 alarm = rtt_readl(rtc, AR);
+	u32 offset;
+
+	offset = gpbr_readl(rtc);
+	if (offset == 0)
+		return -EILSEQ;
+
+	memset(alrm, 0, sizeof(*alrm));
+	if (alarm != ALARM_DISABLED) {
+		rtc_time64_to_tm(offset + alarm, tm);
+
+		dev_dbg(dev, "%s: %ptR\n", __func__, tm);
+
+		if (rtt_readl(rtc, MR) & AT91_RTT_ALMIEN)
+			alrm->enabled = 1;
+	}
+
+	return 0;
+}
+
+static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct sam9_rtc *rtc = dev_get_drvdata(dev);
+	struct rtc_time *tm = &alrm->time;
+	unsigned long secs;
+	u32 offset;
+	u32 mr;
+
+	secs = rtc_tm_to_time64(tm);
+
+	offset = gpbr_readl(rtc);
+	if (offset == 0) {
+		/* time is not set */
+		return -EILSEQ;
+	}
+	mr = rtt_readl(rtc, MR);
+	rtt_writel(rtc, MR, mr & ~AT91_RTT_ALMIEN);
+
+	/* alarm in the past? finish and leave disabled */
+	if (secs <= offset) {
+		rtt_writel(rtc, AR, ALARM_DISABLED);
+		return 0;
+	}
+
+	/* else set alarm and maybe enable it */
+	rtt_writel(rtc, AR, secs - offset);
+	if (alrm->enabled)
+		rtt_writel(rtc, MR, mr | AT91_RTT_ALMIEN);
+
+	dev_dbg(dev, "%s: %ptR\n", __func__, tm);
+
+	return 0;
+}
+
+static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct sam9_rtc *rtc = dev_get_drvdata(dev);
+	u32 mr = rtt_readl(rtc, MR);
+
+	dev_dbg(dev, "alarm_irq_enable: enabled=%08x, mr %08x\n", enabled, mr);
+	if (enabled)
+		rtt_writel(rtc, MR, mr | AT91_RTT_ALMIEN);
+	else
+		rtt_writel(rtc, MR, mr & ~AT91_RTT_ALMIEN);
+	return 0;
+}
+
+/*
+ * Provide additional RTC information in /proc/driver/rtc
+ */
+static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+	struct sam9_rtc *rtc = dev_get_drvdata(dev);
+	u32 mr = rtt_readl(rtc, MR);
+
+	seq_printf(seq, "update_IRQ\t: %s\n",
+		   (mr & AT91_RTT_RTTINCIEN) ? "yes" : "no");
+	return 0;
+}
+
+static irqreturn_t at91_rtc_cache_events(struct sam9_rtc *rtc)
+{
+	u32 sr, mr;
+
+	/* Shared interrupt may be for another device.  Note: reading
+	 * SR clears it, so we must only read it in this irq handler!
+	 */
+	mr = rtt_readl(rtc, MR) & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
+	sr = rtt_readl(rtc, SR) & (mr >> 16);
+	if (!sr)
+		return IRQ_NONE;
+
+	/* alarm status */
+	if (sr & AT91_RTT_ALMS)
+		rtc->events |= (RTC_AF | RTC_IRQF);
+
+	/* timer update/increment */
+	if (sr & AT91_RTT_RTTINC)
+		rtc->events |= (RTC_UF | RTC_IRQF);
+
+	return IRQ_HANDLED;
+}
+
+static void at91_rtc_flush_events(struct sam9_rtc *rtc)
+{
+	if (!rtc->events)
+		return;
+
+	rtc_update_irq(rtc->rtcdev, 1, rtc->events);
+	rtc->events = 0;
+
+	pr_debug("%s: num=%ld, events=0x%02lx\n", __func__,
+		 rtc->events >> 8, rtc->events & 0x000000FF);
+}
+
+/*
+ * IRQ handler for the RTC
+ */
+static irqreturn_t at91_rtc_interrupt(int irq, void *_rtc)
+{
+	struct sam9_rtc *rtc = _rtc;
+	int ret;
+
+	spin_lock(&rtc->lock);
+
+	ret = at91_rtc_cache_events(rtc);
+
+	/* We're called in suspended state */
+	if (rtc->suspended) {
+		/* Mask irqs coming from this peripheral */
+		rtt_writel(rtc, MR,
+			   rtt_readl(rtc, MR) &
+			   ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN));
+		/* Trigger a system wakeup */
+		pm_system_wakeup();
+	} else {
+		at91_rtc_flush_events(rtc);
+	}
+
+	spin_unlock(&rtc->lock);
+
+	return ret;
+}
+
+static const struct rtc_class_ops at91_rtc_ops = {
+	.read_time	= at91_rtc_readtime,
+	.set_time	= at91_rtc_settime,
+	.read_alarm	= at91_rtc_readalarm,
+	.set_alarm	= at91_rtc_setalarm,
+	.proc		= at91_rtc_proc,
+	.alarm_irq_enable = at91_rtc_alarm_irq_enable,
+};
+
+/*
+ * Initialize and install RTC driver
+ */
+static int at91_rtc_probe(struct platform_device *pdev)
+{
+	struct sam9_rtc	*rtc;
+	int		ret, irq;
+	u32		mr;
+	unsigned int	sclk_rate;
+	struct of_phandle_args args;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	spin_lock_init(&rtc->lock);
+	rtc->irq = irq;
+
+	/* platform setup code should have handled this; sigh */
+	if (!device_can_wakeup(&pdev->dev))
+		device_init_wakeup(&pdev->dev, true);
+
+	platform_set_drvdata(pdev, rtc);
+
+	rtc->rtt = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(rtc->rtt))
+		return PTR_ERR(rtc->rtt);
+
+	ret = of_parse_phandle_with_fixed_args(pdev->dev.of_node,
+					       "atmel,rtt-rtc-time-reg", 1, 0,
+					       &args);
+	if (ret)
+		return ret;
+
+	rtc->gpbr = syscon_node_to_regmap(args.np);
+	of_node_put(args.np);
+	rtc->gpbr_offset = args.args[0];
+	if (IS_ERR(rtc->gpbr)) {
+		dev_err(&pdev->dev, "failed to retrieve gpbr regmap, aborting.\n");
+		return -ENOMEM;
+	}
+
+	rtc->sclk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(rtc->sclk))
+		return PTR_ERR(rtc->sclk);
+
+	ret = clk_prepare_enable(rtc->sclk);
+	if (ret) {
+		dev_err(&pdev->dev, "Could not enable slow clock\n");
+		return ret;
+	}
+
+	sclk_rate = clk_get_rate(rtc->sclk);
+	if (!sclk_rate || sclk_rate > AT91_RTT_RTPRES) {
+		dev_err(&pdev->dev, "Invalid slow clock rate\n");
+		ret = -EINVAL;
+		goto err_clk;
+	}
+
+	mr = rtt_readl(rtc, MR);
+
+	/* unless RTT is counting at 1 Hz, re-initialize it */
+	if ((mr & AT91_RTT_RTPRES) != sclk_rate) {
+		mr = AT91_RTT_RTTRST | (sclk_rate & AT91_RTT_RTPRES);
+		gpbr_writel(rtc, 0);
+	}
+
+	/* disable all interrupts (same as on shutdown path) */
+	mr &= ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
+	rtt_writel(rtc, MR, mr);
+
+	rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtc->rtcdev)) {
+		ret = PTR_ERR(rtc->rtcdev);
+		goto err_clk;
+	}
+
+	rtc->rtcdev->ops = &at91_rtc_ops;
+	rtc->rtcdev->range_max = U32_MAX;
+
+	/* register irq handler after we know what name we'll use */
+	ret = devm_request_irq(&pdev->dev, rtc->irq, at91_rtc_interrupt,
+			       IRQF_SHARED | IRQF_COND_SUSPEND,
+			       dev_name(&rtc->rtcdev->dev), rtc);
+	if (ret) {
+		dev_dbg(&pdev->dev, "can't share IRQ %d?\n", rtc->irq);
+		goto err_clk;
+	}
+
+	/* NOTE:  sam9260 rev A silicon has a ROM bug which resets the
+	 * RTT on at least some reboots.  If you have that chip, you must
+	 * initialize the time from some external source like a GPS, wall
+	 * clock, discrete RTC, etc
+	 */
+
+	if (gpbr_readl(rtc) == 0)
+		dev_warn(&pdev->dev, "%s: SET TIME!\n",
+			 dev_name(&rtc->rtcdev->dev));
+
+	return devm_rtc_register_device(rtc->rtcdev);
+
+err_clk:
+	clk_disable_unprepare(rtc->sclk);
+
+	return ret;
+}
+
+/*
+ * Disable and remove the RTC driver
+ */
+static void at91_rtc_remove(struct platform_device *pdev)
+{
+	struct sam9_rtc	*rtc = platform_get_drvdata(pdev);
+	u32		mr = rtt_readl(rtc, MR);
+
+	/* disable all interrupts */
+	rtt_writel(rtc, MR, mr & ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN));
+
+	clk_disable_unprepare(rtc->sclk);
+}
+
+static void at91_rtc_shutdown(struct platform_device *pdev)
+{
+	struct sam9_rtc	*rtc = platform_get_drvdata(pdev);
+	u32		mr = rtt_readl(rtc, MR);
+
+	rtc->imr = mr & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
+	rtt_writel(rtc, MR, mr & ~rtc->imr);
+}
+
+#ifdef CONFIG_PM_SLEEP
+
+/* AT91SAM9 RTC Power management control */
+
+static int at91_rtc_suspend(struct device *dev)
+{
+	struct sam9_rtc	*rtc = dev_get_drvdata(dev);
+	u32		mr = rtt_readl(rtc, MR);
+
+	/*
+	 * This IRQ is shared with DBGU and other hardware which isn't
+	 * necessarily a wakeup event source.
+	 */
+	rtc->imr = mr & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
+	if (rtc->imr) {
+		if (device_may_wakeup(dev) && (mr & AT91_RTT_ALMIEN)) {
+			unsigned long flags;
+
+			enable_irq_wake(rtc->irq);
+			spin_lock_irqsave(&rtc->lock, flags);
+			rtc->suspended = true;
+			spin_unlock_irqrestore(&rtc->lock, flags);
+			/* don't let RTTINC cause wakeups */
+			if (mr & AT91_RTT_RTTINCIEN)
+				rtt_writel(rtc, MR, mr & ~AT91_RTT_RTTINCIEN);
+		} else {
+			rtt_writel(rtc, MR, mr & ~rtc->imr);
+		}
+	}
+
+	return 0;
+}
+
+static int at91_rtc_resume(struct device *dev)
+{
+	struct sam9_rtc	*rtc = dev_get_drvdata(dev);
+	u32		mr;
+
+	if (rtc->imr) {
+		unsigned long flags;
+
+		if (device_may_wakeup(dev))
+			disable_irq_wake(rtc->irq);
+		mr = rtt_readl(rtc, MR);
+		rtt_writel(rtc, MR, mr | rtc->imr);
+
+		spin_lock_irqsave(&rtc->lock, flags);
+		rtc->suspended = false;
+		at91_rtc_cache_events(rtc);
+		at91_rtc_flush_events(rtc);
+		spin_unlock_irqrestore(&rtc->lock, flags);
+	}
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
+
+static const struct of_device_id at91_rtc_dt_ids[] = {
+	{ .compatible = "atmel,at91sam9260-rtt" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
+
+static struct platform_driver at91_rtc_driver = {
+	.probe		= at91_rtc_probe,
+	.remove		= at91_rtc_remove,
+	.shutdown	= at91_rtc_shutdown,
+	.driver		= {
+		.name	= "rtc-at91sam9",
+		.pm	= &at91_rtc_pm_ops,
+		.of_match_table = at91_rtc_dt_ids,
+	},
+};
+
+module_platform_driver(at91_rtc_driver);
+
+MODULE_AUTHOR("Michel Benoit");
+MODULE_DESCRIPTION("RTC driver for Atmel AT91SAM9x");
+MODULE_LICENSE("GPL");