1 files changed, 499 insertions, 0 deletions

diff --git a/arch/i386/kernel/vmitime.c b/arch/i386/kernel/vmitime.c
new file mode 100644
index 000000000000..76d2adcae5a3
--- /dev/null
+++ b/arch/i386/kernel/vmitime.c
@@ -0,0 +1,499 @@
+/*
+ * VMI paravirtual timer support routines.
+ *
+ * Copyright (C) 2005, VMware, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Send feedback to dhecht@vmware.com
+ *
+ */
+
+/*
+ * Portions of this code from arch/i386/kernel/timers/timer_tsc.c.
+ * Portions of the CONFIG_NO_IDLE_HZ code from arch/s390/kernel/time.c.
+ * See comments there for proper credits.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/jiffies.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/rcupdate.h>
+#include <linux/clocksource.h>
+
+#include <asm/timer.h>
+#include <asm/io.h>
+#include <asm/apic.h>
+#include <asm/div64.h>
+#include <asm/timer.h>
+#include <asm/desc.h>
+
+#include <asm/vmi.h>
+#include <asm/vmi_time.h>
+
+#include <mach_timer.h>
+#include <io_ports.h>
+
+#ifdef CONFIG_X86_LOCAL_APIC
+#define VMI_ALARM_WIRING VMI_ALARM_WIRED_LVTT
+#else
+#define VMI_ALARM_WIRING VMI_ALARM_WIRED_IRQ0
+#endif
+
+/* Cached VMI operations */
+struct vmi_timer_ops vmi_timer_ops;
+
+#ifdef CONFIG_NO_IDLE_HZ
+
+/* /proc/sys/kernel/hz_timer state. */
+int sysctl_hz_timer;
+
+/* Some stats */
+static DEFINE_PER_CPU(unsigned long, vmi_idle_no_hz_irqs);
+static DEFINE_PER_CPU(unsigned long, vmi_idle_no_hz_jiffies);
+static DEFINE_PER_CPU(unsigned long, idle_start_jiffies);
+
+#endif /* CONFIG_NO_IDLE_HZ */
+
+/* Number of alarms per second. By default this is CONFIG_VMI_ALARM_HZ. */
+static int alarm_hz = CONFIG_VMI_ALARM_HZ;
+
+/* Cache of the value get_cycle_frequency / HZ. */
+static signed long long cycles_per_jiffy;
+
+/* Cache of the value get_cycle_frequency / alarm_hz. */
+static signed long long cycles_per_alarm;
+
+/* The number of cycles accounted for by the 'jiffies'/'xtime' count.
+ * Protected by xtime_lock. */
+static unsigned long long real_cycles_accounted_system;
+
+/* The number of cycles accounted for by update_process_times(), per cpu. */
+static DEFINE_PER_CPU(unsigned long long, process_times_cycles_accounted_cpu);
+
+/* The number of stolen cycles accounted, per cpu. */
+static DEFINE_PER_CPU(unsigned long long, stolen_cycles_accounted_cpu);
+
+/* Clock source. */
+static cycle_t read_real_cycles(void)
+{
+        return vmi_timer_ops.get_cycle_counter(VMI_CYCLES_REAL);
+}
+
+static cycle_t read_available_cycles(void)
+{
+        return vmi_timer_ops.get_cycle_counter(VMI_CYCLES_AVAILABLE);
+}
+
+#if 0
+static cycle_t read_stolen_cycles(void)
+{
+        return vmi_timer_ops.get_cycle_counter(VMI_CYCLES_STOLEN);
+}
+#endif  /*  0  */
+
+static struct clocksource clocksource_vmi = {
+        .name                   = "vmi-timer",
+        .rating                 = 450,
+        .read                   = read_real_cycles,
+        .mask                   = CLOCKSOURCE_MASK(64),
+        .mult                   = 0, /* to be set */
+        .shift                  = 22,
+        .flags                  = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+
+/* Timer interrupt handler. */
+static irqreturn_t vmi_timer_interrupt(int irq, void *dev_id);
+
+static struct irqaction vmi_timer_irq  = {
+        vmi_timer_interrupt,
+        SA_INTERRUPT,
+        CPU_MASK_NONE,
+        "VMI-alarm",
+        NULL,
+        NULL
+};
+
+/* Alarm rate */
+static int __init vmi_timer_alarm_rate_setup(char* str)
+{
+        int alarm_rate;
+        if (get_option(&str, &alarm_rate) == 1 && alarm_rate > 0) {
+                alarm_hz = alarm_rate;
+                printk(KERN_WARNING "VMI timer alarm HZ set to %d\n", alarm_hz);
+        }
+        return 1;
+}
+__setup("vmi_timer_alarm_hz=", vmi_timer_alarm_rate_setup);
+
+
+/* Initialization */
+static void vmi_get_wallclock_ts(struct timespec *ts)
+{
+        unsigned long long wallclock;
+        wallclock = vmi_timer_ops.get_wallclock(); // nsec units
+        ts->tv_nsec = do_div(wallclock, 1000000000);
+        ts->tv_sec = wallclock;
+}
+
+static void update_xtime_from_wallclock(void)
+{
+        struct timespec ts;
+        vmi_get_wallclock_ts(&ts);
+        do_settimeofday(&ts);
+}
+
+unsigned long vmi_get_wallclock(void)
+{
+        struct timespec ts;
+        vmi_get_wallclock_ts(&ts);
+        return ts.tv_sec;
+}
+
+int vmi_set_wallclock(unsigned long now)
+{
+        return -1;
+}
+
+unsigned long long vmi_sched_clock(void)
+{
+        return read_available_cycles();
+}
+
+void __init vmi_time_init(void)
+{
+        unsigned long long cycles_per_sec, cycles_per_msec;
+        unsigned long flags;
+
+        local_irq_save(flags);
+        setup_irq(0, &vmi_timer_irq);
+#ifdef CONFIG_X86_LOCAL_APIC
+        set_intr_gate(LOCAL_TIMER_VECTOR, apic_vmi_timer_interrupt);
+#endif
+
+        no_sync_cmos_clock = 1;
+
+        vmi_get_wallclock_ts(&xtime);
+        set_normalized_timespec(&wall_to_monotonic,
+                -xtime.tv_sec, -xtime.tv_nsec);
+
+        real_cycles_accounted_system = read_real_cycles();
+        update_xtime_from_wallclock();
+        per_cpu(process_times_cycles_accounted_cpu, 0) = read_available_cycles();
+
+        cycles_per_sec = vmi_timer_ops.get_cycle_frequency();
+
+        cycles_per_jiffy = cycles_per_sec;
+        (void)do_div(cycles_per_jiffy, HZ);
+        cycles_per_alarm = cycles_per_sec;
+        (void)do_div(cycles_per_alarm, alarm_hz);
+        cycles_per_msec = cycles_per_sec;
+        (void)do_div(cycles_per_msec, 1000);
+        cpu_khz = cycles_per_msec;
+
+        printk(KERN_WARNING "VMI timer cycles/sec = %llu ; cycles/jiffy = %llu ;"
+               "cycles/alarm = %llu\n", cycles_per_sec, cycles_per_jiffy,
+               cycles_per_alarm);
+
+        clocksource_vmi.mult = clocksource_khz2mult(cycles_per_msec,
+                                                    clocksource_vmi.shift);
+        if (clocksource_register(&clocksource_vmi))
+                printk(KERN_WARNING "Error registering VMITIME clocksource.");
+
+        /* Disable PIT. */
+        outb_p(0x3a, PIT_MODE); /* binary, mode 5, LSB/MSB, ch 0 */
+
+        /* schedule the alarm. do this in phase with process_times_cycles_accounted_cpu
+         * reduce the latency calling update_process_times. */
+        vmi_timer_ops.set_alarm(
+                      VMI_ALARM_WIRED_IRQ0 | VMI_ALARM_IS_PERIODIC | VMI_CYCLES_AVAILABLE,
+                      per_cpu(process_times_cycles_accounted_cpu, 0) + cycles_per_alarm,
+                      cycles_per_alarm);
+
+        local_irq_restore(flags);
+}
+
+#ifdef CONFIG_X86_LOCAL_APIC
+
+void __init vmi_timer_setup_boot_alarm(void)
+{
+        local_irq_disable();
+
+        /* Route the interrupt to the correct vector. */
+        apic_write_around(APIC_LVTT, LOCAL_TIMER_VECTOR);
+
+        /* Cancel the IRQ0 wired alarm, and setup the LVTT alarm. */
+        vmi_timer_ops.cancel_alarm(VMI_CYCLES_AVAILABLE);
+        vmi_timer_ops.set_alarm(
+                      VMI_ALARM_WIRED_LVTT | VMI_ALARM_IS_PERIODIC | VMI_CYCLES_AVAILABLE,
+                      per_cpu(process_times_cycles_accounted_cpu, 0) + cycles_per_alarm,
+                      cycles_per_alarm);
+        local_irq_enable();
+}
+
+/* Initialize the time accounting variables for an AP on an SMP system.
+ * Also, set the local alarm for the AP. */
+void __init vmi_timer_setup_secondary_alarm(void)
+{
+        int cpu = smp_processor_id();
+
+        /* Route the interrupt to the correct vector. */
+        apic_write_around(APIC_LVTT, LOCAL_TIMER_VECTOR);
+
+        per_cpu(process_times_cycles_accounted_cpu, cpu) = read_available_cycles();
+
+        vmi_timer_ops.set_alarm(
+                      VMI_ALARM_WIRED_LVTT | VMI_ALARM_IS_PERIODIC | VMI_CYCLES_AVAILABLE,
+                      per_cpu(process_times_cycles_accounted_cpu, cpu) + cycles_per_alarm,
+                      cycles_per_alarm);
+}
+
+#endif
+
+/* Update system wide (real) time accounting (e.g. jiffies, xtime). */
+static void vmi_account_real_cycles(unsigned long long cur_real_cycles)
+{
+        long long cycles_not_accounted;
+
+        write_seqlock(&xtime_lock);
+
+        cycles_not_accounted = cur_real_cycles - real_cycles_accounted_system;
+        while (cycles_not_accounted >= cycles_per_jiffy) {
+                /* systems wide jiffies and wallclock. */
+                do_timer(1);
+
+                cycles_not_accounted -= cycles_per_jiffy;
+                real_cycles_accounted_system += cycles_per_jiffy;
+        }
+
+        if (vmi_timer_ops.wallclock_updated())
+                update_xtime_from_wallclock();
+
+        write_sequnlock(&xtime_lock);
+}
+
+/* Update per-cpu process times. */
+static void vmi_account_process_times_cycles(struct pt_regs *regs, int cpu,
+                                             unsigned long long cur_process_times_cycles)
+{
+        long long cycles_not_accounted;
+        cycles_not_accounted = cur_process_times_cycles -
+                per_cpu(process_times_cycles_accounted_cpu, cpu);
+
+        while (cycles_not_accounted >= cycles_per_jiffy) {
+                /* Account time to the current process.  This includes
+                 * calling into the scheduler to decrement the timeslice
+                 * and possibly reschedule.*/
+                update_process_times(user_mode(regs));
+                /* XXX handle /proc/profile multiplier.  */
+                profile_tick(CPU_PROFILING);
+
+                cycles_not_accounted -= cycles_per_jiffy;
+                per_cpu(process_times_cycles_accounted_cpu, cpu) += cycles_per_jiffy;
+        }
+}
+
+#ifdef CONFIG_NO_IDLE_HZ
+/* Update per-cpu idle times.  Used when a no-hz halt is ended. */
+static void vmi_account_no_hz_idle_cycles(int cpu,
+                                          unsigned long long cur_process_times_cycles)
+{
+        long long cycles_not_accounted;
+        unsigned long no_idle_hz_jiffies = 0;
+
+        cycles_not_accounted = cur_process_times_cycles -
+                per_cpu(process_times_cycles_accounted_cpu, cpu);
+
+        while (cycles_not_accounted >= cycles_per_jiffy) {
+                no_idle_hz_jiffies++;
+                cycles_not_accounted -= cycles_per_jiffy;
+                per_cpu(process_times_cycles_accounted_cpu, cpu) += cycles_per_jiffy;
+        }
+        /* Account time to the idle process. */
+        account_steal_time(idle_task(cpu), jiffies_to_cputime(no_idle_hz_jiffies));
+}
+#endif
+
+/* Update per-cpu stolen time. */
+static void vmi_account_stolen_cycles(int cpu,
+                                      unsigned long long cur_real_cycles,
+                                      unsigned long long cur_avail_cycles)
+{
+        long long stolen_cycles_not_accounted;
+        unsigned long stolen_jiffies = 0;
+
+        if (cur_real_cycles < cur_avail_cycles)
+                return;
+
+        stolen_cycles_not_accounted = cur_real_cycles - cur_avail_cycles -
+                per_cpu(stolen_cycles_accounted_cpu, cpu);
+
+        while (stolen_cycles_not_accounted >= cycles_per_jiffy) {
+                stolen_jiffies++;
+                stolen_cycles_not_accounted -= cycles_per_jiffy;
+                per_cpu(stolen_cycles_accounted_cpu, cpu) += cycles_per_jiffy;
+        }
+        /* HACK: pass NULL to force time onto cpustat->steal. */
+        account_steal_time(NULL, jiffies_to_cputime(stolen_jiffies));
+}
+
+/* Body of either IRQ0 interrupt handler (UP no local-APIC) or
+ * local-APIC LVTT interrupt handler (UP & local-APIC or SMP). */
+static void vmi_local_timer_interrupt(int cpu)
+{
+        unsigned long long cur_real_cycles, cur_process_times_cycles;
+
+        cur_real_cycles = read_real_cycles();
+        cur_process_times_cycles = read_available_cycles();
+        /* Update system wide (real) time state (xtime, jiffies). */
+        vmi_account_real_cycles(cur_real_cycles);
+        /* Update per-cpu process times. */
+        vmi_account_process_times_cycles(get_irq_regs(), cpu, cur_process_times_cycles);
+        /* Update time stolen from this cpu by the hypervisor. */
+        vmi_account_stolen_cycles(cpu, cur_real_cycles, cur_process_times_cycles);
+}
+
+#ifdef CONFIG_NO_IDLE_HZ
+
+/* Must be called only from idle loop, with interrupts disabled. */
+int vmi_stop_hz_timer(void)
+{
+        /* Note that cpu_set, cpu_clear are (SMP safe) atomic on x86. */
+
+        unsigned long seq, next;
+        unsigned long long real_cycles_expiry;
+        int cpu = smp_processor_id();
+        int idle;
+
+        BUG_ON(!irqs_disabled());
+        if (sysctl_hz_timer != 0)
+                return 0;
+
+        cpu_set(cpu, nohz_cpu_mask);
+        smp_mb();
+        if (rcu_needs_cpu(cpu) || local_softirq_pending() ||
+            (next = next_timer_interrupt(), time_before_eq(next, jiffies))) {
+                cpu_clear(cpu, nohz_cpu_mask);
+                next = jiffies;
+                idle = 0;
+        } else
+                idle = 1;
+
+        /* Convert jiffies to the real cycle counter. */
+        do {
+                seq = read_seqbegin(&xtime_lock);
+                real_cycles_expiry = real_cycles_accounted_system +
+                        (long)(next - jiffies) * cycles_per_jiffy;
+        } while (read_seqretry(&xtime_lock, seq));
+
+        /* This cpu is going idle. Disable the periodic alarm. */
+        if (idle) {
+                vmi_timer_ops.cancel_alarm(VMI_CYCLES_AVAILABLE);
+                per_cpu(idle_start_jiffies, cpu) = jiffies;
+        }
+
+        /* Set the real time alarm to expire at the next event. */
+        vmi_timer_ops.set_alarm(
+                      VMI_ALARM_WIRING | VMI_ALARM_IS_ONESHOT | VMI_CYCLES_REAL,
+                      real_cycles_expiry, 0);
+
+        return idle;
+}
+
+static void vmi_reenable_hz_timer(int cpu)
+{
+        /* For /proc/vmi/info idle_hz stat. */
+        per_cpu(vmi_idle_no_hz_jiffies, cpu) += jiffies - per_cpu(idle_start_jiffies, cpu);
+        per_cpu(vmi_idle_no_hz_irqs, cpu)++;
+
+        /* Don't bother explicitly cancelling the one-shot alarm -- at
+         * worse we will receive a spurious timer interrupt. */
+        vmi_timer_ops.set_alarm(
+                      VMI_ALARM_WIRING | VMI_ALARM_IS_PERIODIC | VMI_CYCLES_AVAILABLE,
+                      per_cpu(process_times_cycles_accounted_cpu, cpu) + cycles_per_alarm,
+                      cycles_per_alarm);
+        /* Indicate this cpu is no longer nohz idle. */
+        cpu_clear(cpu, nohz_cpu_mask);
+}
+
+/* Called from interrupt handlers when (local) HZ timer is disabled. */
+void vmi_account_time_restart_hz_timer(void)
+{
+        unsigned long long cur_real_cycles, cur_process_times_cycles;
+        int cpu = smp_processor_id();
+
+        BUG_ON(!irqs_disabled());
+        /* Account the time during which the HZ timer was disabled. */
+        cur_real_cycles = read_real_cycles();
+        cur_process_times_cycles = read_available_cycles();
+        /* Update system wide (real) time state (xtime, jiffies). */
+        vmi_account_real_cycles(cur_real_cycles);
+        /* Update per-cpu idle times. */
+        vmi_account_no_hz_idle_cycles(cpu, cur_process_times_cycles);
+        /* Update time stolen from this cpu by the hypervisor. */
+        vmi_account_stolen_cycles(cpu, cur_real_cycles, cur_process_times_cycles);
+        /* Reenable the hz timer. */
+        vmi_reenable_hz_timer(cpu);
+}
+
+#endif /* CONFIG_NO_IDLE_HZ */
+
+/* UP (and no local-APIC) VMI-timer alarm interrupt handler.
+ * Handler for IRQ0. Not used when SMP or X86_LOCAL_APIC after
+ * APIC setup and setup_boot_vmi_alarm() is called.  */
+static irqreturn_t vmi_timer_interrupt(int irq, void *dev_id)
+{
+        vmi_local_timer_interrupt(smp_processor_id());
+        return IRQ_HANDLED;
+}
+
+#ifdef CONFIG_X86_LOCAL_APIC
+
+/* SMP VMI-timer alarm interrupt handler. Handler for LVTT vector.
+ * Also used in UP when CONFIG_X86_LOCAL_APIC.
+ * The wrapper code is from arch/i386/kernel/apic.c#smp_apic_timer_interrupt. */
+void smp_apic_vmi_timer_interrupt(struct pt_regs *regs)
+{
+        struct pt_regs *old_regs = set_irq_regs(regs);
+        int cpu = smp_processor_id();
+
+        /*
+         * the NMI deadlock-detector uses this.
+         */
+        per_cpu(irq_stat,cpu).apic_timer_irqs++;
+
+        /*
+         * NOTE! We'd better ACK the irq immediately,
+         * because timer handling can be slow.
+         */
+        ack_APIC_irq();
+
+        /*
+         * update_process_times() expects us to have done irq_enter().
+         * Besides, if we don't timer interrupts ignore the global
+         * interrupt lock, which is the WrongThing (tm) to do.
+         */
+        irq_enter();
+        vmi_local_timer_interrupt(cpu);
+        irq_exit();
+        set_irq_regs(old_regs);
+}
+
+#endif  /* CONFIG_X86_LOCAL_APIC */