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, 189 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-ep93xx.c b/drivers/clocksource/timer-ep93xx.c
new file mode 100644
index 000000000..1b719282c
--- /dev/null
+++ b/drivers/clocksource/timer-ep93xx.c
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cirrus Logic EP93xx timer driver.
+ * Copyright (C) 2021 Nikita Shubin <nikita.shubin@maquefel.me>
+ *
+ * Based on a rewrite of arch/arm/mach-ep93xx/timer.c:
+ */
+
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+
+#include <asm/mach/time.h>
+
+/*************************************************************************
+ * Timer handling for EP93xx
+ *************************************************************************
+ * The ep93xx has four internal timers.  Timers 1, 2 (both 16 bit) and
+ * 3 (32 bit) count down at 508 kHz, are self-reloading, and can generate
+ * an interrupt on underflow.  Timer 4 (40 bit) counts down at 983.04 kHz,
+ * is free-running, and can't generate interrupts.
+ *
+ * The 508 kHz timers are ideal for use for the timer interrupt, as the
+ * most common values of HZ divide 508 kHz nicely.  We pick the 32 bit
+ * timer (timer 3) to get as long sleep intervals as possible when using
+ * CONFIG_NO_HZ.
+ *
+ * The higher clock rate of timer 4 makes it a better choice than the
+ * other timers for use as clock source and for sched_clock(), providing
+ * a stable 40 bit time base.
+ *************************************************************************
+ */
+
+#define EP93XX_TIMER1_LOAD		0x00
+#define EP93XX_TIMER1_VALUE		0x04
+#define EP93XX_TIMER1_CONTROL		0x08
+#define EP93XX_TIMER123_CONTROL_ENABLE	BIT(7)
+#define EP93XX_TIMER123_CONTROL_MODE	BIT(6)
+#define EP93XX_TIMER123_CONTROL_CLKSEL	BIT(3)
+#define EP93XX_TIMER1_CLEAR		0x0c
+#define EP93XX_TIMER2_LOAD		0x20
+#define EP93XX_TIMER2_VALUE		0x24
+#define EP93XX_TIMER2_CONTROL		0x28
+#define EP93XX_TIMER2_CLEAR		0x2c
+/*
+ * This read-only register contains the low word of the time stamp debug timer
+ * ( Timer4). When this register is read, the high byte of the Timer4 counter is
+ * saved in the Timer4ValueHigh register.
+ */
+#define EP93XX_TIMER4_VALUE_LOW		0x60
+#define EP93XX_TIMER4_VALUE_HIGH	0x64
+#define EP93XX_TIMER4_VALUE_HIGH_ENABLE	BIT(8)
+#define EP93XX_TIMER3_LOAD		0x80
+#define EP93XX_TIMER3_VALUE		0x84
+#define EP93XX_TIMER3_CONTROL		0x88
+#define EP93XX_TIMER3_CLEAR		0x8c
+
+#define EP93XX_TIMER123_RATE		508469
+#define EP93XX_TIMER4_RATE		983040
+
+struct ep93xx_tcu {
+	void __iomem *base;
+};
+
+static struct ep93xx_tcu *ep93xx_tcu;
+
+static u64 ep93xx_clocksource_read(struct clocksource *c)
+{
+	struct ep93xx_tcu *tcu = ep93xx_tcu;
+
+	return lo_hi_readq(tcu->base + EP93XX_TIMER4_VALUE_LOW) & GENMASK_ULL(39, 0);
+}
+
+static u64 notrace ep93xx_read_sched_clock(void)
+{
+	return ep93xx_clocksource_read(NULL);
+}
+
+static int ep93xx_clkevt_set_next_event(unsigned long next,
+					struct clock_event_device *evt)
+{
+	struct ep93xx_tcu *tcu = ep93xx_tcu;
+	/* Default mode: periodic, off, 508 kHz */
+	u32 tmode = EP93XX_TIMER123_CONTROL_MODE |
+	EP93XX_TIMER123_CONTROL_CLKSEL;
+
+	/* Clear timer */
+	writel(tmode, tcu->base + EP93XX_TIMER3_CONTROL);
+
+	/* Set next event */
+	writel(next, tcu->base + EP93XX_TIMER3_LOAD);
+	writel(tmode | EP93XX_TIMER123_CONTROL_ENABLE,
+	       tcu->base + EP93XX_TIMER3_CONTROL);
+	return 0;
+}
+
+static int ep93xx_clkevt_shutdown(struct clock_event_device *evt)
+{
+	struct ep93xx_tcu *tcu = ep93xx_tcu;
+	/* Disable timer */
+	writel(0, tcu->base + EP93XX_TIMER3_CONTROL);
+
+	return 0;
+}
+
+static struct clock_event_device ep93xx_clockevent = {
+	.name			= "timer1",
+	.features		= CLOCK_EVT_FEAT_ONESHOT,
+	.set_state_shutdown	= ep93xx_clkevt_shutdown,
+	.set_state_oneshot	= ep93xx_clkevt_shutdown,
+	.tick_resume		= ep93xx_clkevt_shutdown,
+	.set_next_event		= ep93xx_clkevt_set_next_event,
+	.rating			= 300,
+};
+
+static irqreturn_t ep93xx_timer_interrupt(int irq, void *dev_id)
+{
+	struct ep93xx_tcu *tcu = ep93xx_tcu;
+	struct clock_event_device *evt = dev_id;
+
+	/* Writing any value clears the timer interrupt */
+	writel(1, tcu->base + EP93XX_TIMER3_CLEAR);
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static int __init ep93xx_timer_of_init(struct device_node *np)
+{
+	int irq;
+	unsigned long flags = IRQF_TIMER | IRQF_IRQPOLL;
+	struct ep93xx_tcu *tcu;
+	int ret;
+
+	tcu = kzalloc_obj(*tcu);
+	if (!tcu)
+		return -ENOMEM;
+
+	tcu->base = of_iomap(np, 0);
+	if (!tcu->base) {
+		pr_err("Can't remap registers\n");
+		ret = -ENXIO;
+		goto out_free;
+	}
+
+	ep93xx_tcu = tcu;
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (!irq) {
+		ret = -EINVAL;
+		pr_err("EP93XX Timer Can't parse IRQ %d", irq);
+		goto out_free;
+	}
+
+	/* Enable and register clocksource and sched_clock on timer 4 */
+	writel(EP93XX_TIMER4_VALUE_HIGH_ENABLE,
+	       tcu->base + EP93XX_TIMER4_VALUE_HIGH);
+	clocksource_mmio_init(NULL, "timer4",
+				EP93XX_TIMER4_RATE, 200, 40,
+				ep93xx_clocksource_read);
+	sched_clock_register(ep93xx_read_sched_clock, 40,
+			     EP93XX_TIMER4_RATE);
+
+	/* Set up clockevent on timer 3 */
+	if (request_irq(irq, ep93xx_timer_interrupt, flags, "ep93xx timer",
+		&ep93xx_clockevent))
+		pr_err("Failed to request irq %d (ep93xx timer)\n", irq);
+
+	clockevents_config_and_register(&ep93xx_clockevent,
+				EP93XX_TIMER123_RATE,
+				1,
+				UINT_MAX);
+
+	return 0;
+
+out_free:
+	kfree(tcu);
+	return ret;
+}
+TIMER_OF_DECLARE(ep93xx_timer, "cirrus,ep9301-timer", ep93xx_timer_of_init);