Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
new file mode 100644
index 0000000..2317d4e
--- /dev/null
+++ b/drivers/clocksource/hyperv_timer.c
@@ -0,0 +1,326 @@
+// 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;
+static u64 hv_sched_clock_offset __ro_after_init;
+
+/*
+ * 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);
+
+static struct ms_hyperv_tsc_page tsc_pg __aligned(PAGE_SIZE);
+
+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_clock_tsc(struct clocksource *arg)
+{
+ 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_sched_clock_tsc(void)
+{
+ return read_hv_clock_tsc(NULL) - hv_sched_clock_offset;
+}
+
+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,
+};
+
+static u64 notrace read_hv_clock_msr(struct clocksource *arg)
+{
+ 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_sched_clock_msr(void)
+{
+ return read_hv_clock_msr(NULL) - hv_sched_clock_offset;
+}
+
+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,
+};
+
+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;
+
+ hyperv_cs = &hyperv_cs_tsc;
+ phys_addr = virt_to_phys(&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);
+
+ hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+ hv_setup_sched_clock(read_hv_sched_clock_tsc);
+
+ return true;
+}
+
+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);
+
+ hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+ hv_setup_sched_clock(read_hv_sched_clock_msr);
+}
+EXPORT_SYMBOL_GPL(hv_init_clocksource);