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, 250 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-atmel-st.c b/drivers/clocksource/timer-atmel-st.c
new file mode 100644
index 000000000..73e8aee44
--- /dev/null
+++ b/drivers/clocksource/timer-atmel-st.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * linux/arch/arm/mach-at91/at91rm9200_time.c
+ *
+ *  Copyright (C) 2003 SAN People
+ *  Copyright (C) 2003 ATMEL
+ */
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/export.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/atmel-st.h>
+#include <linux/of_irq.h>
+#include <linux/regmap.h>
+
+static unsigned long last_crtr;
+static u32 irqmask;
+static struct clock_event_device clkevt;
+static struct regmap *regmap_st;
+static int timer_latch;
+
+/*
+ * The ST_CRTR is updated asynchronously to the master clock ... but
+ * the updates as seen by the CPU don't seem to be strictly monotonic.
+ * Waiting until we read the same value twice avoids glitching.
+ */
+static inline unsigned long read_CRTR(void)
+{
+	unsigned int x1, x2;
+
+	regmap_read(regmap_st, AT91_ST_CRTR, &x1);
+	do {
+		regmap_read(regmap_st, AT91_ST_CRTR, &x2);
+		if (x1 == x2)
+			break;
+		x1 = x2;
+	} while (1);
+	return x1;
+}
+
+/*
+ * IRQ handler for the timer.
+ */
+static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id)
+{
+	u32 sr;
+
+	regmap_read(regmap_st, AT91_ST_SR, &sr);
+	sr &= irqmask;
+
+	/*
+	 * irqs should be disabled here, but as the irq is shared they are only
+	 * guaranteed to be off if the timer irq is registered first.
+	 */
+	WARN_ON_ONCE(!irqs_disabled());
+
+	/* simulate "oneshot" timer with alarm */
+	if (sr & AT91_ST_ALMS) {
+		clkevt.event_handler(&clkevt);
+		return IRQ_HANDLED;
+	}
+
+	/* periodic mode should handle delayed ticks */
+	if (sr & AT91_ST_PITS) {
+		u32	crtr = read_CRTR();
+
+		while (((crtr - last_crtr) & AT91_ST_CRTV) >= timer_latch) {
+			last_crtr += timer_latch;
+			clkevt.event_handler(&clkevt);
+		}
+		return IRQ_HANDLED;
+	}
+
+	/* this irq is shared ... */
+	return IRQ_NONE;
+}
+
+static u64 read_clk32k(struct clocksource *cs)
+{
+	return read_CRTR();
+}
+
+static struct clocksource clk32k = {
+	.name		= "32k_counter",
+	.rating		= 150,
+	.read		= read_clk32k,
+	.mask		= CLOCKSOURCE_MASK(20),
+	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static void clkdev32k_disable_and_flush_irq(void)
+{
+	unsigned int val;
+
+	/* Disable and flush pending timer interrupts */
+	regmap_write(regmap_st, AT91_ST_IDR, AT91_ST_PITS | AT91_ST_ALMS);
+	regmap_read(regmap_st, AT91_ST_SR, &val);
+	last_crtr = read_CRTR();
+}
+
+static int clkevt32k_shutdown(struct clock_event_device *evt)
+{
+	clkdev32k_disable_and_flush_irq();
+	irqmask = 0;
+	regmap_write(regmap_st, AT91_ST_IER, irqmask);
+	return 0;
+}
+
+static int clkevt32k_set_oneshot(struct clock_event_device *dev)
+{
+	clkdev32k_disable_and_flush_irq();
+
+	/*
+	 * ALM for oneshot irqs, set by next_event()
+	 * before 32 seconds have passed.
+	 */
+	irqmask = AT91_ST_ALMS;
+	regmap_write(regmap_st, AT91_ST_RTAR, last_crtr);
+	regmap_write(regmap_st, AT91_ST_IER, irqmask);
+	return 0;
+}
+
+static int clkevt32k_set_periodic(struct clock_event_device *dev)
+{
+	clkdev32k_disable_and_flush_irq();
+
+	/* PIT for periodic irqs; fixed rate of 1/HZ */
+	irqmask = AT91_ST_PITS;
+	regmap_write(regmap_st, AT91_ST_PIMR, timer_latch);
+	regmap_write(regmap_st, AT91_ST_IER, irqmask);
+	return 0;
+}
+
+static int
+clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev)
+{
+	u32		alm;
+	unsigned int	val;
+
+	BUG_ON(delta < 2);
+
+	/* The alarm IRQ uses absolute time (now+delta), not the relative
+	 * time (delta) in our calling convention.  Like all clockevents
+	 * using such "match" hardware, we have a race to defend against.
+	 *
+	 * Our defense here is to have set up the clockevent device so the
+	 * delta is at least two.  That way we never end up writing RTAR
+	 * with the value then held in CRTR ... which would mean the match
+	 * wouldn't trigger until 32 seconds later, after CRTR wraps.
+	 */
+	alm = read_CRTR();
+
+	/* Cancel any pending alarm; flush any pending IRQ */
+	regmap_write(regmap_st, AT91_ST_RTAR, alm);
+	regmap_read(regmap_st, AT91_ST_SR, &val);
+
+	/* Schedule alarm by writing RTAR. */
+	alm += delta;
+	regmap_write(regmap_st, AT91_ST_RTAR, alm);
+
+	return 0;
+}
+
+static struct clock_event_device clkevt = {
+	.name			= "at91_tick",
+	.features		= CLOCK_EVT_FEAT_PERIODIC |
+				  CLOCK_EVT_FEAT_ONESHOT,
+	.rating			= 150,
+	.set_next_event		= clkevt32k_next_event,
+	.set_state_shutdown	= clkevt32k_shutdown,
+	.set_state_periodic	= clkevt32k_set_periodic,
+	.set_state_oneshot	= clkevt32k_set_oneshot,
+	.tick_resume		= clkevt32k_shutdown,
+};
+
+/*
+ * ST (system timer) module supports both clockevents and clocksource.
+ */
+static int __init atmel_st_timer_init(struct device_node *node)
+{
+	struct clk *sclk;
+	unsigned int sclk_rate, val;
+	int irq, ret;
+
+	regmap_st = syscon_node_to_regmap(node);
+	if (IS_ERR(regmap_st)) {
+		pr_err("Unable to get regmap\n");
+		return PTR_ERR(regmap_st);
+	}
+
+	/* Disable all timer interrupts, and clear any pending ones */
+	regmap_write(regmap_st, AT91_ST_IDR,
+		AT91_ST_PITS | AT91_ST_WDOVF | AT91_ST_RTTINC | AT91_ST_ALMS);
+	regmap_read(regmap_st, AT91_ST_SR, &val);
+
+	/* Get the interrupts property */
+	irq  = irq_of_parse_and_map(node, 0);
+	if (!irq) {
+		pr_err("Unable to get IRQ from DT\n");
+		return -EINVAL;
+	}
+
+	/* Make IRQs happen for the system timer */
+	ret = request_irq(irq, at91rm9200_timer_interrupt,
+			  IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL,
+			  "at91_tick", regmap_st);
+	if (ret) {
+		pr_err("Unable to setup IRQ\n");
+		return ret;
+	}
+
+	sclk = of_clk_get(node, 0);
+	if (IS_ERR(sclk)) {
+		pr_err("Unable to get slow clock\n");
+		return PTR_ERR(sclk);
+	}
+
+	ret = clk_prepare_enable(sclk);
+	if (ret) {
+		pr_err("Could not enable slow clock\n");
+		return ret;
+	}
+
+	sclk_rate = clk_get_rate(sclk);
+	if (!sclk_rate) {
+		pr_err("Invalid slow clock rate\n");
+		return -EINVAL;
+	}
+	timer_latch = (sclk_rate + HZ / 2) / HZ;
+
+	/* The 32KiHz "Slow Clock" (tick every 30517.58 nanoseconds) is used
+	 * directly for the clocksource and all clockevents, after adjusting
+	 * its prescaler from the 1 Hz default.
+	 */
+	regmap_write(regmap_st, AT91_ST_RTMR, 1);
+
+	/* Setup timer clockevent, with minimum of two ticks (important!!) */
+	clkevt.cpumask = cpumask_of(0);
+	clockevents_config_and_register(&clkevt, sclk_rate,
+					2, AT91_ST_ALMV);
+
+	/* register clocksource */
+	return clocksource_register_hz(&clk32k, sclk_rate);
+}
+TIMER_OF_DECLARE(atmel_st_timer, "atmel,at91rm9200-st",
+		       atmel_st_timer_init);