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-rw-r--r--arch/s390/kernel/time.c382
1 files changed, 382 insertions, 0 deletions
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
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+/*
+ * arch/s390/kernel/time.c
+ * Time of day based timer functions.
+ *
+ * S390 version
+ * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ * Author(s): Hartmut Penner (hp@de.ibm.com),
+ * Martin Schwidefsky (schwidefsky@de.ibm.com),
+ * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
+ *
+ * Derived from "arch/i386/kernel/time.c"
+ * Copyright (C) 1991, 1992, 1995 Linus Torvalds
+ */
+
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/types.h>
+#include <linux/profile.h>
+#include <linux/timex.h>
+#include <linux/notifier.h>
+
+#include <asm/uaccess.h>
+#include <asm/delay.h>
+#include <asm/s390_ext.h>
+#include <asm/div64.h>
+#include <asm/irq.h>
+#include <asm/timer.h>
+
+/* change this if you have some constant time drift */
+#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ)
+#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)
+
+/*
+ * Create a small time difference between the timer interrupts
+ * on the different cpus to avoid lock contention.
+ */
+#define CPU_DEVIATION (smp_processor_id() << 12)
+
+#define TICK_SIZE tick
+
+u64 jiffies_64 = INITIAL_JIFFIES;
+
+EXPORT_SYMBOL(jiffies_64);
+
+static ext_int_info_t ext_int_info_cc;
+static u64 init_timer_cc;
+static u64 jiffies_timer_cc;
+static u64 xtime_cc;
+
+extern unsigned long wall_jiffies;
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ */
+unsigned long long sched_clock(void)
+{
+ return ((get_clock() - jiffies_timer_cc) * 1000) >> 12;
+}
+
+void tod_to_timeval(__u64 todval, struct timespec *xtime)
+{
+ unsigned long long sec;
+
+ sec = todval >> 12;
+ do_div(sec, 1000000);
+ xtime->tv_sec = sec;
+ todval -= (sec * 1000000) << 12;
+ xtime->tv_nsec = ((todval * 1000) >> 12);
+}
+
+static inline unsigned long do_gettimeoffset(void)
+{
+ __u64 now;
+
+ now = (get_clock() - jiffies_timer_cc) >> 12;
+ /* We require the offset from the latest update of xtime */
+ now -= (__u64) wall_jiffies*USECS_PER_JIFFY;
+ return (unsigned long) now;
+}
+
+/*
+ * This version of gettimeofday has microsecond resolution.
+ */
+void do_gettimeofday(struct timeval *tv)
+{
+ unsigned long flags;
+ unsigned long seq;
+ unsigned long usec, sec;
+
+ do {
+ seq = read_seqbegin_irqsave(&xtime_lock, flags);
+
+ sec = xtime.tv_sec;
+ usec = xtime.tv_nsec / 1000 + do_gettimeoffset();
+ } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
+
+ while (usec >= 1000000) {
+ usec -= 1000000;
+ sec++;
+ }
+
+ tv->tv_sec = sec;
+ tv->tv_usec = usec;
+}
+
+EXPORT_SYMBOL(do_gettimeofday);
+
+int do_settimeofday(struct timespec *tv)
+{
+ time_t wtm_sec, sec = tv->tv_sec;
+ long wtm_nsec, nsec = tv->tv_nsec;
+
+ if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
+ return -EINVAL;
+
+ write_seqlock_irq(&xtime_lock);
+ /* This is revolting. We need to set the xtime.tv_nsec
+ * correctly. However, the value in this location is
+ * is value at the last tick.
+ * Discover what correction gettimeofday
+ * would have done, and then undo it!
+ */
+ nsec -= do_gettimeoffset() * 1000;
+
+ wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
+ wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
+
+ set_normalized_timespec(&xtime, sec, nsec);
+ set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
+
+ time_adjust = 0; /* stop active adjtime() */
+ time_status |= STA_UNSYNC;
+ time_maxerror = NTP_PHASE_LIMIT;
+ time_esterror = NTP_PHASE_LIMIT;
+ write_sequnlock_irq(&xtime_lock);
+ clock_was_set();
+ return 0;
+}
+
+EXPORT_SYMBOL(do_settimeofday);
+
+
+#ifdef CONFIG_PROFILING
+#define s390_do_profile(regs) profile_tick(CPU_PROFILING, regs)
+#else
+#define s390_do_profile(regs) do { ; } while(0)
+#endif /* CONFIG_PROFILING */
+
+
+/*
+ * timer_interrupt() needs to keep up the real-time clock,
+ * as well as call the "do_timer()" routine every clocktick
+ */
+void account_ticks(struct pt_regs *regs)
+{
+ __u64 tmp;
+ __u32 ticks, xticks;
+
+ /* Calculate how many ticks have passed. */
+ if (S390_lowcore.int_clock < S390_lowcore.jiffy_timer) {
+ /*
+ * We have to program the clock comparator even if
+ * no tick has passed. That happens if e.g. an i/o
+ * interrupt wakes up an idle processor that has
+ * switched off its hz timer.
+ */
+ tmp = S390_lowcore.jiffy_timer + CPU_DEVIATION;
+ asm volatile ("SCKC %0" : : "m" (tmp));
+ return;
+ }
+ tmp = S390_lowcore.int_clock - S390_lowcore.jiffy_timer;
+ if (tmp >= 2*CLK_TICKS_PER_JIFFY) { /* more than two ticks ? */
+ ticks = __div(tmp, CLK_TICKS_PER_JIFFY) + 1;
+ S390_lowcore.jiffy_timer +=
+ CLK_TICKS_PER_JIFFY * (__u64) ticks;
+ } else if (tmp >= CLK_TICKS_PER_JIFFY) {
+ ticks = 2;
+ S390_lowcore.jiffy_timer += 2*CLK_TICKS_PER_JIFFY;
+ } else {
+ ticks = 1;
+ S390_lowcore.jiffy_timer += CLK_TICKS_PER_JIFFY;
+ }
+
+ /* set clock comparator for next tick */
+ tmp = S390_lowcore.jiffy_timer + CPU_DEVIATION;
+ asm volatile ("SCKC %0" : : "m" (tmp));
+
+#ifdef CONFIG_SMP
+ /*
+ * Do not rely on the boot cpu to do the calls to do_timer.
+ * Spread it over all cpus instead.
+ */
+ write_seqlock(&xtime_lock);
+ if (S390_lowcore.jiffy_timer > xtime_cc) {
+ tmp = S390_lowcore.jiffy_timer - xtime_cc;
+ if (tmp >= 2*CLK_TICKS_PER_JIFFY) {
+ xticks = __div(tmp, CLK_TICKS_PER_JIFFY);
+ xtime_cc += (__u64) xticks * CLK_TICKS_PER_JIFFY;
+ } else {
+ xticks = 1;
+ xtime_cc += CLK_TICKS_PER_JIFFY;
+ }
+ while (xticks--)
+ do_timer(regs);
+ }
+ write_sequnlock(&xtime_lock);
+#else
+ for (xticks = ticks; xticks > 0; xticks--)
+ do_timer(regs);
+#endif
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+ account_user_vtime(current);
+#else
+ while (ticks--)
+ update_process_times(user_mode(regs));
+#endif
+
+ s390_do_profile(regs);
+}
+
+#ifdef CONFIG_NO_IDLE_HZ
+
+#ifdef CONFIG_NO_IDLE_HZ_INIT
+int sysctl_hz_timer = 0;
+#else
+int sysctl_hz_timer = 1;
+#endif
+
+/*
+ * Stop the HZ tick on the current CPU.
+ * Only cpu_idle may call this function.
+ */
+static inline void stop_hz_timer(void)
+{
+ __u64 timer;
+
+ if (sysctl_hz_timer != 0)
+ return;
+
+ cpu_set(smp_processor_id(), nohz_cpu_mask);
+
+ /*
+ * Leave the clock comparator set up for the next timer
+ * tick if either rcu or a softirq is pending.
+ */
+ if (rcu_pending(smp_processor_id()) || local_softirq_pending()) {
+ cpu_clear(smp_processor_id(), nohz_cpu_mask);
+ return;
+ }
+
+ /*
+ * This cpu is going really idle. Set up the clock comparator
+ * for the next event.
+ */
+ timer = (__u64) (next_timer_interrupt() - jiffies) + jiffies_64;
+ timer = jiffies_timer_cc + timer * CLK_TICKS_PER_JIFFY;
+ asm volatile ("SCKC %0" : : "m" (timer));
+}
+
+/*
+ * Start the HZ tick on the current CPU.
+ * Only cpu_idle may call this function.
+ */
+static inline void start_hz_timer(void)
+{
+ if (!cpu_isset(smp_processor_id(), nohz_cpu_mask))
+ return;
+ account_ticks(__KSTK_PTREGS(current));
+ cpu_clear(smp_processor_id(), nohz_cpu_mask);
+}
+
+static int nohz_idle_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ switch (action) {
+ case CPU_IDLE:
+ stop_hz_timer();
+ break;
+ case CPU_NOT_IDLE:
+ start_hz_timer();
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block nohz_idle_nb = {
+ .notifier_call = nohz_idle_notify,
+};
+
+void __init nohz_init(void)
+{
+ if (register_idle_notifier(&nohz_idle_nb))
+ panic("Couldn't register idle notifier");
+}
+
+#endif
+
+/*
+ * Start the clock comparator on the current CPU.
+ */
+void init_cpu_timer(void)
+{
+ unsigned long cr0;
+ __u64 timer;
+
+ timer = jiffies_timer_cc + jiffies_64 * CLK_TICKS_PER_JIFFY;
+ S390_lowcore.jiffy_timer = timer + CLK_TICKS_PER_JIFFY;
+ timer += CLK_TICKS_PER_JIFFY + CPU_DEVIATION;
+ asm volatile ("SCKC %0" : : "m" (timer));
+ /* allow clock comparator timer interrupt */
+ __ctl_store(cr0, 0, 0);
+ cr0 |= 0x800;
+ __ctl_load(cr0, 0, 0);
+}
+
+extern void vtime_init(void);
+
+/*
+ * Initialize the TOD clock and the CPU timer of
+ * the boot cpu.
+ */
+void __init time_init(void)
+{
+ __u64 set_time_cc;
+ int cc;
+
+ /* kick the TOD clock */
+ asm volatile ("STCK 0(%1)\n\t"
+ "IPM %0\n\t"
+ "SRL %0,28" : "=r" (cc) : "a" (&init_timer_cc)
+ : "memory", "cc");
+ switch (cc) {
+ case 0: /* clock in set state: all is fine */
+ break;
+ case 1: /* clock in non-set state: FIXME */
+ printk("time_init: TOD clock in non-set state\n");
+ break;
+ case 2: /* clock in error state: FIXME */
+ printk("time_init: TOD clock in error state\n");
+ break;
+ case 3: /* clock in stopped or not-operational state: FIXME */
+ printk("time_init: TOD clock stopped/non-operational\n");
+ break;
+ }
+ jiffies_timer_cc = init_timer_cc - jiffies_64 * CLK_TICKS_PER_JIFFY;
+
+ /* set xtime */
+ xtime_cc = init_timer_cc + CLK_TICKS_PER_JIFFY;
+ set_time_cc = init_timer_cc - 0x8126d60e46000000LL +
+ (0x3c26700LL*1000000*4096);
+ tod_to_timeval(set_time_cc, &xtime);
+ set_normalized_timespec(&wall_to_monotonic,
+ -xtime.tv_sec, -xtime.tv_nsec);
+
+ /* request the clock comparator external interrupt */
+ if (register_early_external_interrupt(0x1004, 0,
+ &ext_int_info_cc) != 0)
+ panic("Couldn't request external interrupt 0x1004");
+
+ init_cpu_timer();
+
+#ifdef CONFIG_NO_IDLE_HZ
+ nohz_init();
+#endif
+
+#ifdef CONFIG_VIRT_TIMER
+ vtime_init();
+#endif
+}
+
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