Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 255 insertions, 0 deletions

diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
new file mode 100644
index 000000000000..8b8a5a45b621
--- /dev/null
+++ b/arch/ia64/kernel/time.c
@@ -0,0 +1,255 @@
+/*
+ * linux/arch/ia64/kernel/time.c
+ *
+ * Copyright (C) 1998-2003 Hewlett-Packard Co
+ *      Stephane Eranian <eranian@hpl.hp.com>
+ *      David Mosberger <davidm@hpl.hp.com>
+ * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
+ * Copyright (C) 1999-2000 VA Linux Systems
+ * Copyright (C) 1999-2000 Walt Drummond <drummond@valinux.com>
+ */
+#include <linux/config.h>
+
+#include <linux/cpu.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/profile.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/interrupt.h>
+#include <linux/efi.h>
+#include <linux/profile.h>
+#include <linux/timex.h>
+
+#include <asm/machvec.h>
+#include <asm/delay.h>
+#include <asm/hw_irq.h>
+#include <asm/ptrace.h>
+#include <asm/sal.h>
+#include <asm/sections.h>
+#include <asm/system.h>
+
+extern unsigned long wall_jiffies;
+
+u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
+
+EXPORT_SYMBOL(jiffies_64);
+
+#define TIME_KEEPER_ID  0       /* smp_processor_id() of time-keeper */
+
+#ifdef CONFIG_IA64_DEBUG_IRQ
+
+unsigned long last_cli_ip;
+EXPORT_SYMBOL(last_cli_ip);
+
+#endif
+
+static struct time_interpolator itc_interpolator = {
+        .shift = 16,
+        .mask = 0xffffffffffffffffLL,
+        .source = TIME_SOURCE_CPU
+};
+
+static irqreturn_t
+timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
+{
+        unsigned long new_itm;
+
+        if (unlikely(cpu_is_offline(smp_processor_id()))) {
+                return IRQ_HANDLED;
+        }
+
+        platform_timer_interrupt(irq, dev_id, regs);
+
+        new_itm = local_cpu_data->itm_next;
+
+        if (!time_after(ia64_get_itc(), new_itm))
+                printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n",
+                       ia64_get_itc(), new_itm);
+
+        profile_tick(CPU_PROFILING, regs);
+
+        while (1) {
+                update_process_times(user_mode(regs));
+
+                new_itm += local_cpu_data->itm_delta;
+
+                if (smp_processor_id() == TIME_KEEPER_ID) {
+                        /*
+                         * Here we are in the timer irq handler. We have irqs locally
+                         * disabled, but we don't know if the timer_bh is running on
+                         * another CPU. We need to avoid to SMP race by acquiring the
+                         * xtime_lock.
+                         */
+                        write_seqlock(&xtime_lock);
+                        do_timer(regs);
+                        local_cpu_data->itm_next = new_itm;
+                        write_sequnlock(&xtime_lock);
+                } else
+                        local_cpu_data->itm_next = new_itm;
+
+                if (time_after(new_itm, ia64_get_itc()))
+                        break;
+        }
+
+        do {
+                /*
+                 * If we're too close to the next clock tick for
+                 * comfort, we increase the safety margin by
+                 * intentionally dropping the next tick(s).  We do NOT
+                 * update itm.next because that would force us to call
+                 * do_timer() which in turn would let our clock run
+                 * too fast (with the potentially devastating effect
+                 * of losing monotony of time).
+                 */
+                while (!time_after(new_itm, ia64_get_itc() + local_cpu_data->itm_delta/2))
+                        new_itm += local_cpu_data->itm_delta;
+                ia64_set_itm(new_itm);
+                /* double check, in case we got hit by a (slow) PMI: */
+        } while (time_after_eq(ia64_get_itc(), new_itm));
+        return IRQ_HANDLED;
+}
+
+/*
+ * Encapsulate access to the itm structure for SMP.
+ */
+void
+ia64_cpu_local_tick (void)
+{
+        int cpu = smp_processor_id();
+        unsigned long shift = 0, delta;
+
+        /* arrange for the cycle counter to generate a timer interrupt: */
+        ia64_set_itv(IA64_TIMER_VECTOR);
+
+        delta = local_cpu_data->itm_delta;
+        /*
+         * Stagger the timer tick for each CPU so they don't occur all at (almost) the
+         * same time:
+         */
+        if (cpu) {
+                unsigned long hi = 1UL << ia64_fls(cpu);
+                shift = (2*(cpu - hi) + 1) * delta/hi/2;
+        }
+        local_cpu_data->itm_next = ia64_get_itc() + delta + shift;
+        ia64_set_itm(local_cpu_data->itm_next);
+}
+
+static int nojitter;
+
+static int __init nojitter_setup(char *str)
+{
+        nojitter = 1;
+        printk("Jitter checking for ITC timers disabled\n");
+        return 1;
+}
+
+__setup("nojitter", nojitter_setup);
+
+
+void __devinit
+ia64_init_itm (void)
+{
+        unsigned long platform_base_freq, itc_freq;
+        struct pal_freq_ratio itc_ratio, proc_ratio;
+        long status, platform_base_drift, itc_drift;
+
+        /*
+         * According to SAL v2.6, we need to use a SAL call to determine the platform base
+         * frequency and then a PAL call to determine the frequency ratio between the ITC
+         * and the base frequency.
+         */
+        status = ia64_sal_freq_base(SAL_FREQ_BASE_PLATFORM,
+                                    &platform_base_freq, &platform_base_drift);
+        if (status != 0) {
+                printk(KERN_ERR "SAL_FREQ_BASE_PLATFORM failed: %s\n", ia64_sal_strerror(status));
+        } else {
+                status = ia64_pal_freq_ratios(&proc_ratio, NULL, &itc_ratio);
+                if (status != 0)
+                        printk(KERN_ERR "PAL_FREQ_RATIOS failed with status=%ld\n", status);
+        }
+        if (status != 0) {
+                /* invent "random" values */
+                printk(KERN_ERR
+                       "SAL/PAL failed to obtain frequency info---inventing reasonable values\n");
+                platform_base_freq = 100000000;
+                platform_base_drift = -1;       /* no drift info */
+                itc_ratio.num = 3;
+                itc_ratio.den = 1;
+        }
+        if (platform_base_freq < 40000000) {
+                printk(KERN_ERR "Platform base frequency %lu bogus---resetting to 75MHz!\n",
+                       platform_base_freq);
+                platform_base_freq = 75000000;
+                platform_base_drift = -1;
+        }
+        if (!proc_ratio.den)
+                proc_ratio.den = 1;     /* avoid division by zero */
+        if (!itc_ratio.den)
+                itc_ratio.den = 1;      /* avoid division by zero */
+
+        itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den;
+
+        local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ;
+        printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%lu/%lu, "
+               "ITC freq=%lu.%03luMHz", smp_processor_id(),
+               platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000,
+               itc_ratio.num, itc_ratio.den, itc_freq / 1000000, (itc_freq / 1000) % 1000);
+
+        if (platform_base_drift != -1) {
+                itc_drift = platform_base_drift*itc_ratio.num/itc_ratio.den;
+                printk("+/-%ldppm\n", itc_drift);
+        } else {
+                itc_drift = -1;
+                printk("\n");
+        }
+
+        local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den;
+        local_cpu_data->itc_freq = itc_freq;
+        local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC;
+        local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT)
+                                        + itc_freq/2)/itc_freq;
+
+        if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
+                itc_interpolator.frequency = local_cpu_data->itc_freq;
+                itc_interpolator.drift = itc_drift;
+#ifdef CONFIG_SMP
+                /* On IA64 in an SMP configuration ITCs are never accurately synchronized.
+                 * Jitter compensation requires a cmpxchg which may limit
+                 * the scalability of the syscalls for retrieving time.
+                 * The ITC synchronization is usually successful to within a few
+                 * ITC ticks but this is not a sure thing. If you need to improve
+                 * timer performance in SMP situations then boot the kernel with the
+                 * "nojitter" option. However, doing so may result in time fluctuating (maybe
+                 * even going backward) if the ITC offsets between the individual CPUs
+                 * are too large.
+                 */
+                if (!nojitter) itc_interpolator.jitter = 1;
+#endif
+                register_time_interpolator(&itc_interpolator);
+        }
+
+        /* Setup the CPU local timer tick */
+        ia64_cpu_local_tick();
+}
+
+static struct irqaction timer_irqaction = {
+        .handler =      timer_interrupt,
+        .flags =        SA_INTERRUPT,
+        .name =         "timer"
+};
+
+void __init
+time_init (void)
+{
+        register_percpu_irq(IA64_TIMER_VECTOR, &timer_irqaction);
+        efi_gettimeofday(&xtime);
+        ia64_init_itm();
+
+        /*
+         * Initialize wall_to_monotonic such that adding it to xtime will yield zero, the
+         * tv_nsec field must be normalized (i.e., 0 <= nsec < NSEC_PER_SEC).
+         */
+        set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec);
+}