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-cs5535.c b/drivers/clocksource/timer-cs5535.c
new file mode 100644
index 000000000..8af666c39
--- /dev/null
+++ b/drivers/clocksource/timer-cs5535.c
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Clock event driver for the CS5535/CS5536
+ *
+ * Copyright (C) 2006, Advanced Micro Devices, Inc.
+ * Copyright (C) 2007  Andres Salomon <dilinger@debian.org>
+ * Copyright (C) 2009  Andres Salomon <dilinger@collabora.co.uk>
+ *
+ * The MFGPTs are documented in AMD Geode CS5536 Companion Device Data Book.
+ */
+
+#include <linux/kernel.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/cs5535.h>
+#include <linux/clockchips.h>
+
+#define DRV_NAME "cs5535-clockevt"
+
+static int timer_irq;
+module_param_hw_named(irq, timer_irq, int, irq, 0644);
+MODULE_PARM_DESC(irq, "Which IRQ to use for the clock source MFGPT ticks.");
+
+/*
+ * We are using the 32.768kHz input clock - it's the only one that has the
+ * ranges we find desirable.  The following table lists the suitable
+ * divisors and the associated Hz, minimum interval and the maximum interval:
+ *
+ *  Divisor   Hz      Min Delta (s)  Max Delta (s)
+ *   1        32768   .00048828125      2.000
+ *   2        16384   .0009765625       4.000
+ *   4         8192   .001953125        8.000
+ *   8         4096   .00390625        16.000
+ *   16        2048   .0078125         32.000
+ *   32        1024   .015625          64.000
+ *   64         512   .03125          128.000
+ *  128         256   .0625           256.000
+ *  256         128   .125            512.000
+ */
+
+static struct cs5535_mfgpt_timer *cs5535_event_clock;
+
+/* Selected from the table above */
+
+#define MFGPT_DIVISOR 16
+#define MFGPT_SCALE  4     /* divisor = 2^(scale) */
+#define MFGPT_HZ  (32768 / MFGPT_DIVISOR)
+#define MFGPT_PERIODIC (MFGPT_HZ / HZ)
+
+/*
+ * The MFGPT timers on the CS5536 provide us with suitable timers to use
+ * as clock event sources - not as good as a HPET or APIC, but certainly
+ * better than the PIT.  This isn't a general purpose MFGPT driver, but
+ * a simplified one designed specifically to act as a clock event source.
+ * For full details about the MFGPT, please consult the CS5536 data sheet.
+ */
+
+static void disable_timer(struct cs5535_mfgpt_timer *timer)
+{
+	/* avoid races by clearing CMP1 and CMP2 unconditionally */
+	cs5535_mfgpt_write(timer, MFGPT_REG_SETUP,
+			(uint16_t) ~MFGPT_SETUP_CNTEN | MFGPT_SETUP_CMP1 |
+				MFGPT_SETUP_CMP2);
+}
+
+static void start_timer(struct cs5535_mfgpt_timer *timer, uint16_t delta)
+{
+	cs5535_mfgpt_write(timer, MFGPT_REG_CMP2, delta);
+	cs5535_mfgpt_write(timer, MFGPT_REG_COUNTER, 0);
+
+	cs5535_mfgpt_write(timer, MFGPT_REG_SETUP,
+			MFGPT_SETUP_CNTEN | MFGPT_SETUP_CMP2);
+}
+
+static int mfgpt_shutdown(struct clock_event_device *evt)
+{
+	disable_timer(cs5535_event_clock);
+	return 0;
+}
+
+static int mfgpt_set_periodic(struct clock_event_device *evt)
+{
+	disable_timer(cs5535_event_clock);
+	start_timer(cs5535_event_clock, MFGPT_PERIODIC);
+	return 0;
+}
+
+static int mfgpt_next_event(unsigned long delta, struct clock_event_device *evt)
+{
+	start_timer(cs5535_event_clock, delta);
+	return 0;
+}
+
+static struct clock_event_device cs5535_clockevent = {
+	.name = DRV_NAME,
+	.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+	.set_state_shutdown = mfgpt_shutdown,
+	.set_state_periodic = mfgpt_set_periodic,
+	.set_state_oneshot = mfgpt_shutdown,
+	.tick_resume = mfgpt_shutdown,
+	.set_next_event = mfgpt_next_event,
+	.rating = 250,
+	.owner = THIS_MODULE,
+};
+
+static irqreturn_t mfgpt_tick(int irq, void *dev_id)
+{
+	uint16_t val = cs5535_mfgpt_read(cs5535_event_clock, MFGPT_REG_SETUP);
+
+	/* See if the interrupt was for us */
+	if (!(val & (MFGPT_SETUP_SETUP | MFGPT_SETUP_CMP2 | MFGPT_SETUP_CMP1)))
+		return IRQ_NONE;
+
+	/* Turn off the clock (and clear the event) */
+	disable_timer(cs5535_event_clock);
+
+	if (clockevent_state_detached(&cs5535_clockevent) ||
+	    clockevent_state_shutdown(&cs5535_clockevent))
+		return IRQ_HANDLED;
+
+	/* Clear the counter */
+	cs5535_mfgpt_write(cs5535_event_clock, MFGPT_REG_COUNTER, 0);
+
+	/* Restart the clock in periodic mode */
+
+	if (clockevent_state_periodic(&cs5535_clockevent))
+		cs5535_mfgpt_write(cs5535_event_clock, MFGPT_REG_SETUP,
+				MFGPT_SETUP_CNTEN | MFGPT_SETUP_CMP2);
+
+	cs5535_clockevent.event_handler(&cs5535_clockevent);
+	return IRQ_HANDLED;
+}
+
+static int __init cs5535_mfgpt_init(void)
+{
+	unsigned long flags = IRQF_NOBALANCING | IRQF_TIMER | IRQF_SHARED;
+	struct cs5535_mfgpt_timer *timer;
+	int ret;
+	uint16_t val;
+
+	timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
+	if (!timer) {
+		printk(KERN_ERR DRV_NAME ": Could not allocate MFGPT timer\n");
+		return -ENODEV;
+	}
+	cs5535_event_clock = timer;
+
+	/* Set up the IRQ on the MFGPT side */
+	if (cs5535_mfgpt_setup_irq(timer, MFGPT_CMP2, &timer_irq)) {
+		printk(KERN_ERR DRV_NAME ": Could not set up IRQ %d\n",
+				timer_irq);
+		goto err_timer;
+	}
+
+	/* And register it with the kernel */
+	ret = request_irq(timer_irq, mfgpt_tick, flags, DRV_NAME, timer);
+	if (ret) {
+		printk(KERN_ERR DRV_NAME ": Unable to set up the interrupt.\n");
+		goto err_irq;
+	}
+
+	/* Set the clock scale and enable the event mode for CMP2 */
+	val = MFGPT_SCALE | (3 << 8);
+
+	cs5535_mfgpt_write(cs5535_event_clock, MFGPT_REG_SETUP, val);
+
+	/* Set up the clock event */
+	printk(KERN_INFO DRV_NAME
+		": Registering MFGPT timer as a clock event, using IRQ %d\n",
+		timer_irq);
+	clockevents_config_and_register(&cs5535_clockevent, MFGPT_HZ,
+					0xF, 0xFFFE);
+
+	return 0;
+
+err_irq:
+	cs5535_mfgpt_release_irq(cs5535_event_clock, MFGPT_CMP2, &timer_irq);
+err_timer:
+	cs5535_mfgpt_free_timer(cs5535_event_clock);
+	printk(KERN_ERR DRV_NAME ": Unable to set up the MFGPT clock source\n");
+	return -EIO;
+}
+
+module_init(cs5535_mfgpt_init);
+
+MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
+MODULE_DESCRIPTION("CS5535/CS5536 MFGPT clock event driver");
+MODULE_LICENSE("GPL");