Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 373 insertions, 0 deletions

diff --git a/drivers/clocksource/arc_timer.c b/drivers/clocksource/arc_timer.c
new file mode 100644
index 000000000..cb18524cc
--- /dev/null
+++ b/drivers/clocksource/arc_timer.c
@@ -0,0 +1,373 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016-17 Synopsys, Inc. (www.synopsys.com)
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ */
+
+/* ARC700 has two 32bit independent prog Timers: TIMER0 and TIMER1, Each can be
+ * programmed to go from @count to @limit and optionally interrupt.
+ * We've designated TIMER0 for clockevents and TIMER1 for clocksource
+ *
+ * ARCv2 based HS38 cores have RTC (in-core) and GFRC (inside ARConnect/MCIP)
+ * which are suitable for UP and SMP based clocksources respectively
+ */
+
+#include <linux/interrupt.h>
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+
+#include <soc/arc/timers.h>
+#include <soc/arc/mcip.h>
+
+
+static unsigned long arc_timer_freq;
+
+static int noinline arc_get_timer_clk(struct device_node *node)
+{
+	struct clk *clk;
+	int ret;
+
+	clk = of_clk_get(node, 0);
+	if (IS_ERR(clk)) {
+		pr_err("timer missing clk\n");
+		return PTR_ERR(clk);
+	}
+
+	ret = clk_prepare_enable(clk);
+	if (ret) {
+		pr_err("Couldn't enable parent clk\n");
+		return ret;
+	}
+
+	arc_timer_freq = clk_get_rate(clk);
+
+	return 0;
+}
+
+/********** Clock Source Device *********/
+
+#ifdef CONFIG_ARC_TIMERS_64BIT
+
+static u64 arc_read_gfrc(struct clocksource *cs)
+{
+	unsigned long flags;
+	u32 l, h;
+
+	/*
+	 * From a programming model pov, there seems to be just one instance of
+	 * MCIP_CMD/MCIP_READBACK however micro-architecturally there's
+	 * an instance PER ARC CORE (not per cluster), and there are dedicated
+	 * hardware decode logic (per core) inside ARConnect to handle
+	 * simultaneous read/write accesses from cores via those two registers.
+	 * So several concurrent commands to ARConnect are OK if they are
+	 * trying to access two different sub-components (like GFRC,
+	 * inter-core interrupt, etc...). HW also supports simultaneously
+	 * accessing GFRC by multiple cores.
+	 * That's why it is safe to disable hard interrupts on the local CPU
+	 * before access to GFRC instead of taking global MCIP spinlock
+	 * defined in arch/arc/kernel/mcip.c
+	 */
+	local_irq_save(flags);
+
+	__mcip_cmd(CMD_GFRC_READ_LO, 0);
+	l = read_aux_reg(ARC_REG_MCIP_READBACK);
+
+	__mcip_cmd(CMD_GFRC_READ_HI, 0);
+	h = read_aux_reg(ARC_REG_MCIP_READBACK);
+
+	local_irq_restore(flags);
+
+	return (((u64)h) << 32) | l;
+}
+
+static notrace u64 arc_gfrc_clock_read(void)
+{
+	return arc_read_gfrc(NULL);
+}
+
+static struct clocksource arc_counter_gfrc = {
+	.name   = "ARConnect GFRC",
+	.rating = 400,
+	.read   = arc_read_gfrc,
+	.mask   = CLOCKSOURCE_MASK(64),
+	.flags  = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static int __init arc_cs_setup_gfrc(struct device_node *node)
+{
+	struct mcip_bcr mp;
+	int ret;
+
+	READ_BCR(ARC_REG_MCIP_BCR, mp);
+	if (!mp.gfrc) {
+		pr_warn("Global-64-bit-Ctr clocksource not detected\n");
+		return -ENXIO;
+	}
+
+	ret = arc_get_timer_clk(node);
+	if (ret)
+		return ret;
+
+	sched_clock_register(arc_gfrc_clock_read, 64, arc_timer_freq);
+
+	return clocksource_register_hz(&arc_counter_gfrc, arc_timer_freq);
+}
+TIMER_OF_DECLARE(arc_gfrc, "snps,archs-timer-gfrc", arc_cs_setup_gfrc);
+
+#define AUX_RTC_CTRL	0x103
+#define AUX_RTC_LOW	0x104
+#define AUX_RTC_HIGH	0x105
+
+static u64 arc_read_rtc(struct clocksource *cs)
+{
+	unsigned long status;
+	u32 l, h;
+
+	/*
+	 * hardware has an internal state machine which tracks readout of
+	 * low/high and updates the CTRL.status if
+	 *  - interrupt/exception taken between the two reads
+	 *  - high increments after low has been read
+	 */
+	do {
+		l = read_aux_reg(AUX_RTC_LOW);
+		h = read_aux_reg(AUX_RTC_HIGH);
+		status = read_aux_reg(AUX_RTC_CTRL);
+	} while (!(status & BIT(31)));
+
+	return (((u64)h) << 32) | l;
+}
+
+static notrace u64 arc_rtc_clock_read(void)
+{
+	return arc_read_rtc(NULL);
+}
+
+static struct clocksource arc_counter_rtc = {
+	.name   = "ARCv2 RTC",
+	.rating = 350,
+	.read   = arc_read_rtc,
+	.mask   = CLOCKSOURCE_MASK(64),
+	.flags  = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static int __init arc_cs_setup_rtc(struct device_node *node)
+{
+	struct bcr_timer timer;
+	int ret;
+
+	READ_BCR(ARC_REG_TIMERS_BCR, timer);
+	if (!timer.rtc) {
+		pr_warn("Local-64-bit-Ctr clocksource not detected\n");
+		return -ENXIO;
+	}
+
+	/* Local to CPU hence not usable in SMP */
+	if (IS_ENABLED(CONFIG_SMP)) {
+		pr_warn("Local-64-bit-Ctr not usable in SMP\n");
+		return -EINVAL;
+	}
+
+	ret = arc_get_timer_clk(node);
+	if (ret)
+		return ret;
+
+	write_aux_reg(AUX_RTC_CTRL, 1);
+
+	sched_clock_register(arc_rtc_clock_read, 64, arc_timer_freq);
+
+	return clocksource_register_hz(&arc_counter_rtc, arc_timer_freq);
+}
+TIMER_OF_DECLARE(arc_rtc, "snps,archs-timer-rtc", arc_cs_setup_rtc);
+
+#endif
+
+/*
+ * 32bit TIMER1 to keep counting monotonically and wraparound
+ */
+
+static u64 arc_read_timer1(struct clocksource *cs)
+{
+	return (u64) read_aux_reg(ARC_REG_TIMER1_CNT);
+}
+
+static notrace u64 arc_timer1_clock_read(void)
+{
+	return arc_read_timer1(NULL);
+}
+
+static struct clocksource arc_counter_timer1 = {
+	.name   = "ARC Timer1",
+	.rating = 300,
+	.read   = arc_read_timer1,
+	.mask   = CLOCKSOURCE_MASK(32),
+	.flags  = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static int __init arc_cs_setup_timer1(struct device_node *node)
+{
+	int ret;
+
+	/* Local to CPU hence not usable in SMP */
+	if (IS_ENABLED(CONFIG_SMP))
+		return -EINVAL;
+
+	ret = arc_get_timer_clk(node);
+	if (ret)
+		return ret;
+
+	write_aux_reg(ARC_REG_TIMER1_LIMIT, ARC_TIMERN_MAX);
+	write_aux_reg(ARC_REG_TIMER1_CNT, 0);
+	write_aux_reg(ARC_REG_TIMER1_CTRL, ARC_TIMER_CTRL_NH);
+
+	sched_clock_register(arc_timer1_clock_read, 32, arc_timer_freq);
+
+	return clocksource_register_hz(&arc_counter_timer1, arc_timer_freq);
+}
+
+/********** Clock Event Device *********/
+
+static int arc_timer_irq;
+
+/*
+ * Arm the timer to interrupt after @cycles
+ * The distinction for oneshot/periodic is done in arc_event_timer_ack() below
+ */
+static void arc_timer_event_setup(unsigned int cycles)
+{
+	write_aux_reg(ARC_REG_TIMER0_LIMIT, cycles);
+	write_aux_reg(ARC_REG_TIMER0_CNT, 0);	/* start from 0 */
+
+	write_aux_reg(ARC_REG_TIMER0_CTRL, ARC_TIMER_CTRL_IE | ARC_TIMER_CTRL_NH);
+}
+
+
+static int arc_clkevent_set_next_event(unsigned long delta,
+				       struct clock_event_device *dev)
+{
+	arc_timer_event_setup(delta);
+	return 0;
+}
+
+static int arc_clkevent_set_periodic(struct clock_event_device *dev)
+{
+	/*
+	 * At X Hz, 1 sec = 1000ms -> X cycles;
+	 *		      10ms -> X / 100 cycles
+	 */
+	arc_timer_event_setup(arc_timer_freq / HZ);
+	return 0;
+}
+
+static DEFINE_PER_CPU(struct clock_event_device, arc_clockevent_device) = {
+	.name			= "ARC Timer0",
+	.features		= CLOCK_EVT_FEAT_ONESHOT |
+				  CLOCK_EVT_FEAT_PERIODIC,
+	.rating			= 300,
+	.set_next_event		= arc_clkevent_set_next_event,
+	.set_state_periodic	= arc_clkevent_set_periodic,
+};
+
+static irqreturn_t timer_irq_handler(int irq, void *dev_id)
+{
+	/*
+	 * Note that generic IRQ core could have passed @evt for @dev_id if
+	 * irq_set_chip_and_handler() asked for handle_percpu_devid_irq()
+	 */
+	struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);
+	int irq_reenable = clockevent_state_periodic(evt);
+
+	/*
+	 * 1. ACK the interrupt
+	 *    - For ARC700, any write to CTRL reg ACKs it, so just rewrite
+	 *      Count when [N]ot [H]alted bit.
+	 *    - For HS3x, it is a bit subtle. On taken count-down interrupt,
+	 *      IP bit [3] is set, which needs to be cleared for ACK'ing.
+	 *      The write below can only update the other two bits, hence
+	 *      explicitly clears IP bit
+	 * 2. Re-arm interrupt if periodic by writing to IE bit [0]
+	 */
+	write_aux_reg(ARC_REG_TIMER0_CTRL, irq_reenable | ARC_TIMER_CTRL_NH);
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+
+static int arc_timer_starting_cpu(unsigned int cpu)
+{
+	struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);
+
+	evt->cpumask = cpumask_of(smp_processor_id());
+
+	clockevents_config_and_register(evt, arc_timer_freq, 0, ARC_TIMERN_MAX);
+	enable_percpu_irq(arc_timer_irq, 0);
+	return 0;
+}
+
+static int arc_timer_dying_cpu(unsigned int cpu)
+{
+	disable_percpu_irq(arc_timer_irq);
+	return 0;
+}
+
+/*
+ * clockevent setup for boot CPU
+ */
+static int __init arc_clockevent_setup(struct device_node *node)
+{
+	struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);
+	int ret;
+
+	arc_timer_irq = irq_of_parse_and_map(node, 0);
+	if (arc_timer_irq <= 0) {
+		pr_err("clockevent: missing irq\n");
+		return -EINVAL;
+	}
+
+	ret = arc_get_timer_clk(node);
+	if (ret)
+		return ret;
+
+	/* Needs apriori irq_set_percpu_devid() done in intc map function */
+	ret = request_percpu_irq(arc_timer_irq, timer_irq_handler,
+				 "Timer0 (per-cpu-tick)", evt);
+	if (ret) {
+		pr_err("clockevent: unable to request irq\n");
+		return ret;
+	}
+
+	ret = cpuhp_setup_state(CPUHP_AP_ARC_TIMER_STARTING,
+				"clockevents/arc/timer:starting",
+				arc_timer_starting_cpu,
+				arc_timer_dying_cpu);
+	if (ret) {
+		pr_err("Failed to setup hotplug state\n");
+		return ret;
+	}
+	return 0;
+}
+
+static int __init arc_of_timer_init(struct device_node *np)
+{
+	static int init_count = 0;
+	int ret;
+
+	if (!init_count) {
+		init_count = 1;
+		ret = arc_clockevent_setup(np);
+	} else {
+		ret = arc_cs_setup_timer1(np);
+	}
+
+	return ret;
+}
+TIMER_OF_DECLARE(arc_clkevt, "snps,arc-timer", arc_of_timer_init);