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, 335 insertions, 0 deletions

diff --git a/drivers/clocksource/timer-stm32.c b/drivers/clocksource/timer-stm32.c
new file mode 100644
index 000000000..fee65914f
--- /dev/null
+++ b/drivers/clocksource/timer-stm32.c
@@ -0,0 +1,335 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) Maxime Coquelin 2015
+ * Author:  Maxime Coquelin <mcoquelin.stm32@gmail.com>
+ *
+ * Inspired by time-efm32.c from Uwe Kleine-Koenig
+ */
+
+#include <linux/kernel.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/delay.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/clk.h>
+#include <linux/reset.h>
+#include <linux/sched_clock.h>
+#include <linux/slab.h>
+
+#include "timer-of.h"
+
+#define TIM_CR1		0x00
+#define TIM_DIER	0x0c
+#define TIM_SR		0x10
+#define TIM_EGR		0x14
+#define TIM_CNT		0x24
+#define TIM_PSC		0x28
+#define TIM_ARR		0x2c
+#define TIM_CCR1	0x34
+
+#define TIM_CR1_CEN	BIT(0)
+#define TIM_CR1_UDIS	BIT(1)
+#define TIM_CR1_OPM	BIT(3)
+#define TIM_CR1_ARPE	BIT(7)
+
+#define TIM_DIER_UIE	BIT(0)
+#define TIM_DIER_CC1IE	BIT(1)
+
+#define TIM_SR_UIF	BIT(0)
+
+#define TIM_EGR_UG	BIT(0)
+
+#define TIM_PSC_MAX	USHRT_MAX
+#define TIM_PSC_CLKRATE	10000
+
+struct stm32_timer_private {
+	int bits;
+};
+
+/**
+ * stm32_timer_of_bits_set - set accessor helper
+ * @to: a timer_of structure pointer
+ * @bits: the number of bits (16 or 32)
+ *
+ * Accessor helper to set the number of bits in the timer-of private
+ * structure.
+ *
+ */
+static void stm32_timer_of_bits_set(struct timer_of *to, int bits)
+{
+	struct stm32_timer_private *pd = to->private_data;
+
+	pd->bits = bits;
+}
+
+/**
+ * stm32_timer_of_bits_get - get accessor helper
+ * @to: a timer_of structure pointer
+ *
+ * Accessor helper to get the number of bits in the timer-of private
+ * structure.
+ *
+ * Returns: an integer corresponding to the number of bits.
+ */
+static int stm32_timer_of_bits_get(struct timer_of *to)
+{
+	struct stm32_timer_private *pd = to->private_data;
+
+	return pd->bits;
+}
+
+static void __iomem *stm32_timer_cnt __read_mostly;
+
+static u64 notrace stm32_read_sched_clock(void)
+{
+	return readl_relaxed(stm32_timer_cnt);
+}
+
+static struct delay_timer stm32_timer_delay;
+
+static unsigned long stm32_read_delay(void)
+{
+	return readl_relaxed(stm32_timer_cnt);
+}
+
+static void stm32_clock_event_disable(struct timer_of *to)
+{
+	writel_relaxed(0, timer_of_base(to) + TIM_DIER);
+}
+
+/**
+ * stm32_timer_start - Start the counter without event
+ * @to: a timer_of structure pointer
+ *
+ * Start the timer in order to have the counter reset and start
+ * incrementing but disable interrupt event when there is a counter
+ * overflow. By default, the counter direction is used as upcounter.
+ */
+static void stm32_timer_start(struct timer_of *to)
+{
+	writel_relaxed(TIM_CR1_UDIS | TIM_CR1_CEN, timer_of_base(to) + TIM_CR1);
+}
+
+static int stm32_clock_event_shutdown(struct clock_event_device *clkevt)
+{
+	struct timer_of *to = to_timer_of(clkevt);
+
+	stm32_clock_event_disable(to);
+
+	return 0;
+}
+
+static int stm32_clock_event_set_next_event(unsigned long evt,
+					    struct clock_event_device *clkevt)
+{
+	struct timer_of *to = to_timer_of(clkevt);
+	unsigned long now, next;
+
+	next = readl_relaxed(timer_of_base(to) + TIM_CNT) + evt;
+	writel_relaxed(next, timer_of_base(to) + TIM_CCR1);
+	now = readl_relaxed(timer_of_base(to) + TIM_CNT);
+
+	if ((next - now) > evt)
+		return -ETIME;
+
+	writel_relaxed(TIM_DIER_CC1IE, timer_of_base(to) + TIM_DIER);
+
+	return 0;
+}
+
+static int stm32_clock_event_set_periodic(struct clock_event_device *clkevt)
+{
+	struct timer_of *to = to_timer_of(clkevt);
+
+	stm32_timer_start(to);
+
+	return stm32_clock_event_set_next_event(timer_of_period(to), clkevt);
+}
+
+static int stm32_clock_event_set_oneshot(struct clock_event_device *clkevt)
+{
+	struct timer_of *to = to_timer_of(clkevt);
+
+	stm32_timer_start(to);
+
+	return 0;
+}
+
+static irqreturn_t stm32_clock_event_handler(int irq, void *dev_id)
+{
+	struct clock_event_device *clkevt = (struct clock_event_device *)dev_id;
+	struct timer_of *to = to_timer_of(clkevt);
+
+	writel_relaxed(0, timer_of_base(to) + TIM_SR);
+
+	if (clockevent_state_periodic(clkevt))
+		stm32_clock_event_set_periodic(clkevt);
+	else
+		stm32_clock_event_shutdown(clkevt);
+
+	clkevt->event_handler(clkevt);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * stm32_timer_set_width - Sort out the timer width (32/16)
+ * @to: a pointer to a timer-of structure
+ *
+ * Write the 32-bit max value and read/return the result. If the timer
+ * is 32 bits wide, the result will be UINT_MAX, otherwise it will
+ * be truncated by the 16-bit register to USHRT_MAX.
+ *
+ */
+static void __init stm32_timer_set_width(struct timer_of *to)
+{
+	u32 width;
+
+	writel_relaxed(UINT_MAX, timer_of_base(to) + TIM_ARR);
+
+	width = readl_relaxed(timer_of_base(to) + TIM_ARR);
+
+	stm32_timer_of_bits_set(to, width == UINT_MAX ? 32 : 16);
+}
+
+/**
+ * stm32_timer_set_prescaler - Compute and set the prescaler register
+ * @to: a pointer to a timer-of structure
+ *
+ * Depending on the timer width, compute the prescaler to always
+ * target a 10MHz timer rate for 16 bits. 32-bit timers are
+ * considered precise and long enough to not use the prescaler.
+ */
+static void __init stm32_timer_set_prescaler(struct timer_of *to)
+{
+	int prescaler = 1;
+
+	if (stm32_timer_of_bits_get(to) != 32) {
+		prescaler = DIV_ROUND_CLOSEST(timer_of_rate(to),
+					      TIM_PSC_CLKRATE);
+		/*
+		 * The prescaler register is an u16, the variable
+		 * can't be greater than TIM_PSC_MAX, let's cap it in
+		 * this case.
+		 */
+		prescaler = prescaler < TIM_PSC_MAX ? prescaler : TIM_PSC_MAX;
+	}
+
+	writel_relaxed(prescaler - 1, timer_of_base(to) + TIM_PSC);
+	writel_relaxed(TIM_EGR_UG, timer_of_base(to) + TIM_EGR);
+	writel_relaxed(0, timer_of_base(to) + TIM_SR);
+
+	/* Adjust rate and period given the prescaler value */
+	to->of_clk.rate = DIV_ROUND_CLOSEST(to->of_clk.rate, prescaler);
+	to->of_clk.period = DIV_ROUND_UP(to->of_clk.rate, HZ);
+}
+
+static int __init stm32_clocksource_init(struct timer_of *to)
+{
+        u32 bits = stm32_timer_of_bits_get(to);
+	const char *name = to->np->full_name;
+
+	/*
+	 * This driver allows to register several timers and relies on
+	 * the generic time framework to select the right one.
+	 * However, nothing allows to do the same for the
+	 * sched_clock. We are not interested in a sched_clock for the
+	 * 16-bit timers but only for the 32-bit one, so if no 32-bit
+	 * timer is registered yet, we select this 32-bit timer as a
+	 * sched_clock.
+	 */
+	if (bits == 32 && !stm32_timer_cnt) {
+
+		/*
+		 * Start immediately the counter as we will be using
+		 * it right after.
+		 */
+		stm32_timer_start(to);
+
+		stm32_timer_cnt = timer_of_base(to) + TIM_CNT;
+		sched_clock_register(stm32_read_sched_clock, bits, timer_of_rate(to));
+		pr_info("%s: STM32 sched_clock registered\n", name);
+
+		stm32_timer_delay.read_current_timer = stm32_read_delay;
+		stm32_timer_delay.freq = timer_of_rate(to);
+		register_current_timer_delay(&stm32_timer_delay);
+		pr_info("%s: STM32 delay timer registered\n", name);
+	}
+
+	return clocksource_mmio_init(timer_of_base(to) + TIM_CNT, name,
+				     timer_of_rate(to), bits == 32 ? 250 : 100,
+				     bits, clocksource_mmio_readl_up);
+}
+
+static void __init stm32_clockevent_init(struct timer_of *to)
+{
+	u32 bits = stm32_timer_of_bits_get(to);
+
+	to->clkevt.name = to->np->full_name;
+	to->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+	to->clkevt.set_state_shutdown = stm32_clock_event_shutdown;
+	to->clkevt.set_state_periodic = stm32_clock_event_set_periodic;
+	to->clkevt.set_state_oneshot = stm32_clock_event_set_oneshot;
+	to->clkevt.tick_resume = stm32_clock_event_shutdown;
+	to->clkevt.set_next_event = stm32_clock_event_set_next_event;
+	to->clkevt.rating = bits == 32 ? 250 : 100;
+
+	clockevents_config_and_register(&to->clkevt, timer_of_rate(to), 0x1,
+					(1 <<  bits) - 1);
+
+	pr_info("%pOF: STM32 clockevent driver initialized (%d bits)\n",
+		to->np, bits);
+}
+
+static int __init stm32_timer_init(struct device_node *node)
+{
+	struct reset_control *rstc;
+	struct timer_of *to;
+	int ret;
+
+	to = kzalloc_obj(*to);
+	if (!to)
+		return -ENOMEM;
+
+	to->flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE;
+	to->of_irq.handler = stm32_clock_event_handler;
+
+	ret = timer_of_init(node, to);
+	if (ret)
+		goto err;
+
+	to->private_data = kzalloc_obj(struct stm32_timer_private);
+	if (!to->private_data) {
+		ret = -ENOMEM;
+		goto deinit;
+	}
+
+	rstc = of_reset_control_get(node, NULL);
+	if (!IS_ERR(rstc)) {
+		reset_control_assert(rstc);
+		reset_control_deassert(rstc);
+	}
+
+	stm32_timer_set_width(to);
+
+	stm32_timer_set_prescaler(to);
+
+	ret = stm32_clocksource_init(to);
+	if (ret)
+		goto deinit;
+
+	stm32_clockevent_init(to);
+	return 0;
+
+deinit:
+	timer_of_cleanup(to);
+err:
+	kfree(to);
+	return ret;
+}
+
+TIMER_OF_DECLARE(stm32, "st,stm32-timer", stm32_timer_init);