Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "The timer and timekeeping departement delivers:

  Core:

   - The consolidation of the VDSO code into a generic library including
     the conversion of x86 and ARM64. Conversion of ARM and MIPS are en
     route through the relevant maintainer trees and should end up in
     5.4.

     This gets rid of the unnecessary different copies of the same code
     and brings all architectures on the same level of VDSO
     functionality.

   - Make the NTP user space interface more robust by restricting the
     TAI offset to prevent undefined behaviour. Includes a selftest.

   - Validate user input in the compat settimeofday() syscall to catch
     invalid values which would be turned into valid values by a
     multiplication overflow

   - Consolidate the time accessors

   - Small fixes, improvements and cleanups all over the place

  Drivers:

   - Support for the NXP system counter, TI davinci timer

   - Move the Microsoft HyperV clocksource/events code into the
     drivers/clocksource directory so it can be shared between x86 and
     ARM64.

   - Overhaul of the Tegra driver

   - Delay timer support for IXP4xx

   - Small fixes, improvements and cleanups as usual"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits)
  time: Validate user input in compat_settimeofday()
  timer: Document TIMER_PINNED
  clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic
  clocksource/drivers: Make Hyper-V clocksource ISA agnostic
  MAINTAINERS: Fix Andy's surname and the directory entries of VDSO
  hrtimer: Use a bullet for the returns bullet list
  arm64: vdso: Fix compilation with clang older than 8
  arm64: compat: Fix __arch_get_hw_counter() implementation
  arm64: Fix __arch_get_hw_counter() implementation
  lib/vdso: Make delta calculation work correctly
  MAINTAINERS: Add entry for the generic VDSO library
  arm64: compat: No need for pre-ARMv7 barriers on an ARMv8 system
  arm64: vdso: Remove unnecessary asm-offsets.c definitions
  vdso: Remove superfluous #ifdef __KERNEL__ in vdso/datapage.h
  clocksource/drivers/davinci: Add support for clocksource
  clocksource/drivers/davinci: Add support for clockevents
  clocksource/drivers/tegra: Set up maximum-ticks limit properly
  clocksource/drivers/tegra: Cycles can't be 0
  clocksource/drivers/tegra: Restore base address before cleanup
  clocksource/drivers/tegra: Add verbose definition for 1MHz constant
  ...

1 files changed, 339 insertions, 0 deletions

diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
new file mode 100644
index 000000000000..ba2c79e6a0ee
--- /dev/null
+++ b/drivers/clocksource/hyperv_timer.c
@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Clocksource driver for the synthetic counter and timers
+ * provided by the Hyper-V hypervisor to guest VMs, as described
+ * in the Hyper-V Top Level Functional Spec (TLFS). This driver
+ * is instruction set architecture independent.
+ *
+ * Copyright (C) 2019, Microsoft, Inc.
+ *
+ * Author:  Michael Kelley <mikelley@microsoft.com>
+ */
+
+#include <linux/percpu.h>
+#include <linux/cpumask.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/sched_clock.h>
+#include <linux/mm.h>
+#include <clocksource/hyperv_timer.h>
+#include <asm/hyperv-tlfs.h>
+#include <asm/mshyperv.h>
+
+static struct clock_event_device __percpu *hv_clock_event;
+
+/*
+ * If false, we're using the old mechanism for stimer0 interrupts
+ * where it sends a VMbus message when it expires. The old
+ * mechanism is used when running on older versions of Hyper-V
+ * that don't support Direct Mode. While Hyper-V provides
+ * four stimer's per CPU, Linux uses only stimer0.
+ */
+static bool direct_mode_enabled;
+
+static int stimer0_irq;
+static int stimer0_vector;
+static int stimer0_message_sint;
+
+/*
+ * ISR for when stimer0 is operating in Direct Mode.  Direct Mode
+ * does not use VMbus or any VMbus messages, so process here and not
+ * in the VMbus driver code.
+ */
+void hv_stimer0_isr(void)
+{
+	struct clock_event_device *ce;
+
+	ce = this_cpu_ptr(hv_clock_event);
+	ce->event_handler(ce);
+}
+EXPORT_SYMBOL_GPL(hv_stimer0_isr);
+
+static int hv_ce_set_next_event(unsigned long delta,
+				struct clock_event_device *evt)
+{
+	u64 current_tick;
+
+	current_tick = hyperv_cs->read(NULL);
+	current_tick += delta;
+	hv_init_timer(0, current_tick);
+	return 0;
+}
+
+static int hv_ce_shutdown(struct clock_event_device *evt)
+{
+	hv_init_timer(0, 0);
+	hv_init_timer_config(0, 0);
+	if (direct_mode_enabled)
+		hv_disable_stimer0_percpu_irq(stimer0_irq);
+
+	return 0;
+}
+
+static int hv_ce_set_oneshot(struct clock_event_device *evt)
+{
+	union hv_stimer_config timer_cfg;
+
+	timer_cfg.as_uint64 = 0;
+	timer_cfg.enable = 1;
+	timer_cfg.auto_enable = 1;
+	if (direct_mode_enabled) {
+		/*
+		 * When it expires, the timer will directly interrupt
+		 * on the specified hardware vector/IRQ.
+		 */
+		timer_cfg.direct_mode = 1;
+		timer_cfg.apic_vector = stimer0_vector;
+		hv_enable_stimer0_percpu_irq(stimer0_irq);
+	} else {
+		/*
+		 * When it expires, the timer will generate a VMbus message,
+		 * to be handled by the normal VMbus interrupt handler.
+		 */
+		timer_cfg.direct_mode = 0;
+		timer_cfg.sintx = stimer0_message_sint;
+	}
+	hv_init_timer_config(0, timer_cfg.as_uint64);
+	return 0;
+}
+
+/*
+ * hv_stimer_init - Per-cpu initialization of the clockevent
+ */
+void hv_stimer_init(unsigned int cpu)
+{
+	struct clock_event_device *ce;
+
+	/*
+	 * Synthetic timers are always available except on old versions of
+	 * Hyper-V on x86.  In that case, just return as Linux will use a
+	 * clocksource based on emulated PIT or LAPIC timer hardware.
+	 */
+	if (!(ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE))
+		return;
+
+	ce = per_cpu_ptr(hv_clock_event, cpu);
+	ce->name = "Hyper-V clockevent";
+	ce->features = CLOCK_EVT_FEAT_ONESHOT;
+	ce->cpumask = cpumask_of(cpu);
+	ce->rating = 1000;
+	ce->set_state_shutdown = hv_ce_shutdown;
+	ce->set_state_oneshot = hv_ce_set_oneshot;
+	ce->set_next_event = hv_ce_set_next_event;
+
+	clockevents_config_and_register(ce,
+					HV_CLOCK_HZ,
+					HV_MIN_DELTA_TICKS,
+					HV_MAX_MAX_DELTA_TICKS);
+}
+EXPORT_SYMBOL_GPL(hv_stimer_init);
+
+/*
+ * hv_stimer_cleanup - Per-cpu cleanup of the clockevent
+ */
+void hv_stimer_cleanup(unsigned int cpu)
+{
+	struct clock_event_device *ce;
+
+	/* Turn off clockevent device */
+	if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
+		ce = per_cpu_ptr(hv_clock_event, cpu);
+		hv_ce_shutdown(ce);
+	}
+}
+EXPORT_SYMBOL_GPL(hv_stimer_cleanup);
+
+/* hv_stimer_alloc - Global initialization of the clockevent and stimer0 */
+int hv_stimer_alloc(int sint)
+{
+	int ret;
+
+	hv_clock_event = alloc_percpu(struct clock_event_device);
+	if (!hv_clock_event)
+		return -ENOMEM;
+
+	direct_mode_enabled = ms_hyperv.misc_features &
+			HV_STIMER_DIRECT_MODE_AVAILABLE;
+	if (direct_mode_enabled) {
+		ret = hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector,
+				hv_stimer0_isr);
+		if (ret) {
+			free_percpu(hv_clock_event);
+			hv_clock_event = NULL;
+			return ret;
+		}
+	}
+
+	stimer0_message_sint = sint;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hv_stimer_alloc);
+
+/* hv_stimer_free - Free global resources allocated by hv_stimer_alloc() */
+void hv_stimer_free(void)
+{
+	if (direct_mode_enabled && (stimer0_irq != 0)) {
+		hv_remove_stimer0_irq(stimer0_irq);
+		stimer0_irq = 0;
+	}
+	free_percpu(hv_clock_event);
+	hv_clock_event = NULL;
+}
+EXPORT_SYMBOL_GPL(hv_stimer_free);
+
+/*
+ * Do a global cleanup of clockevents for the cases of kexec and
+ * vmbus exit
+ */
+void hv_stimer_global_cleanup(void)
+{
+	int	cpu;
+	struct clock_event_device *ce;
+
+	if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) {
+		for_each_present_cpu(cpu) {
+			ce = per_cpu_ptr(hv_clock_event, cpu);
+			clockevents_unbind_device(ce, cpu);
+		}
+	}
+	hv_stimer_free();
+}
+EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup);
+
+/*
+ * Code and definitions for the Hyper-V clocksources.  Two
+ * clocksources are defined: one that reads the Hyper-V defined MSR, and
+ * the other that uses the TSC reference page feature as defined in the
+ * TLFS.  The MSR version is for compatibility with old versions of
+ * Hyper-V and 32-bit x86.  The TSC reference page version is preferred.
+ */
+
+struct clocksource *hyperv_cs;
+EXPORT_SYMBOL_GPL(hyperv_cs);
+
+#ifdef CONFIG_HYPERV_TSCPAGE
+
+static struct ms_hyperv_tsc_page *tsc_pg;
+
+struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
+{
+	return tsc_pg;
+}
+EXPORT_SYMBOL_GPL(hv_get_tsc_page);
+
+static u64 notrace read_hv_sched_clock_tsc(void)
+{
+	u64 current_tick = hv_read_tsc_page(tsc_pg);
+
+	if (current_tick == U64_MAX)
+		hv_get_time_ref_count(current_tick);
+
+	return current_tick;
+}
+
+static u64 read_hv_clock_tsc(struct clocksource *arg)
+{
+	return read_hv_sched_clock_tsc();
+}
+
+static struct clocksource hyperv_cs_tsc = {
+	.name	= "hyperv_clocksource_tsc_page",
+	.rating	= 400,
+	.read	= read_hv_clock_tsc,
+	.mask	= CLOCKSOURCE_MASK(64),
+	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+#endif
+
+static u64 notrace read_hv_sched_clock_msr(void)
+{
+	u64 current_tick;
+	/*
+	 * Read the partition counter to get the current tick count. This count
+	 * is set to 0 when the partition is created and is incremented in
+	 * 100 nanosecond units.
+	 */
+	hv_get_time_ref_count(current_tick);
+	return current_tick;
+}
+
+static u64 read_hv_clock_msr(struct clocksource *arg)
+{
+	return read_hv_sched_clock_msr();
+}
+
+static struct clocksource hyperv_cs_msr = {
+	.name	= "hyperv_clocksource_msr",
+	.rating	= 400,
+	.read	= read_hv_clock_msr,
+	.mask	= CLOCKSOURCE_MASK(64),
+	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+#ifdef CONFIG_HYPERV_TSCPAGE
+static bool __init hv_init_tsc_clocksource(void)
+{
+	u64		tsc_msr;
+	phys_addr_t	phys_addr;
+
+	if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
+		return false;
+
+	tsc_pg = vmalloc(PAGE_SIZE);
+	if (!tsc_pg)
+		return false;
+
+	hyperv_cs = &hyperv_cs_tsc;
+	phys_addr = page_to_phys(vmalloc_to_page(tsc_pg));
+
+	/*
+	 * The Hyper-V TLFS specifies to preserve the value of reserved
+	 * bits in registers. So read the existing value, preserve the
+	 * low order 12 bits, and add in the guest physical address
+	 * (which already has at least the low 12 bits set to zero since
+	 * it is page aligned). Also set the "enable" bit, which is bit 0.
+	 */
+	hv_get_reference_tsc(tsc_msr);
+	tsc_msr &= GENMASK_ULL(11, 0);
+	tsc_msr = tsc_msr | 0x1 | (u64)phys_addr;
+	hv_set_reference_tsc(tsc_msr);
+
+	hv_set_clocksource_vdso(hyperv_cs_tsc);
+	clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
+
+	/* sched_clock_register is needed on ARM64 but is a no-op on x86 */
+	sched_clock_register(read_hv_sched_clock_tsc, 64, HV_CLOCK_HZ);
+	return true;
+}
+#else
+static bool __init hv_init_tsc_clocksource(void)
+{
+	return false;
+}
+#endif
+
+
+void __init hv_init_clocksource(void)
+{
+	/*
+	 * Try to set up the TSC page clocksource. If it succeeds, we're
+	 * done. Otherwise, set up the MSR clocksoruce.  At least one of
+	 * these will always be available except on very old versions of
+	 * Hyper-V on x86.  In that case we won't have a Hyper-V
+	 * clocksource, but Linux will still run with a clocksource based
+	 * on the emulated PIT or LAPIC timer.
+	 */
+	if (hv_init_tsc_clocksource())
+		return;
+
+	if (!(ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE))
+		return;
+
+	hyperv_cs = &hyperv_cs_msr;
+	clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
+
+	/* sched_clock_register is needed on ARM64 but is a no-op on x86 */
+	sched_clock_register(read_hv_sched_clock_msr, 64, HV_CLOCK_HZ);
+}
+EXPORT_SYMBOL_GPL(hv_init_clocksource);