1 files changed, 182 insertions, 0 deletions

diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
new file mode 100644
index 000000000000..552ca1cb9847
--- /dev/null
+++ b/arch/um/kernel/time.c
@@ -0,0 +1,182 @@
+/*
+ * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#include "linux/kernel.h"
+#include "linux/module.h"
+#include "linux/unistd.h"
+#include "linux/stddef.h"
+#include "linux/spinlock.h"
+#include "linux/time.h"
+#include "linux/sched.h"
+#include "linux/interrupt.h"
+#include "linux/init.h"
+#include "linux/delay.h"
+#include "linux/hrtimer.h"
+#include "asm/irq.h"
+#include "asm/param.h"
+#include "asm/current.h"
+#include "kern_util.h"
+#include "user_util.h"
+#include "mode.h"
+#include "os.h"
+
+int hz(void)
+{
+        return(HZ);
+}
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ */
+unsigned long long sched_clock(void)
+{
+        return (unsigned long long)jiffies_64 * (1000000000 / HZ);
+}
+
+/* Changed at early boot */
+int timer_irq_inited = 0;
+
+static unsigned long long prev_nsecs;
+#ifdef CONFIG_UML_REAL_TIME_CLOCK
+static long long delta;                 /* Deviation per interval */
+#endif
+
+void timer_irq(union uml_pt_regs *regs)
+{
+        unsigned long long ticks = 0;
+
+#ifdef CONFIG_UML_REAL_TIME_CLOCK
+        if(prev_nsecs){
+                /* We've had 1 tick */
+                unsigned long long nsecs = os_nsecs();
+
+                delta += nsecs - prev_nsecs;
+                prev_nsecs = nsecs;
+
+                /* Protect against the host clock being set backwards */
+                if(delta < 0)
+                        delta = 0;
+
+                ticks += (delta * HZ) / BILLION;
+                delta -= (ticks * BILLION) / HZ;
+        }
+        else prev_nsecs = os_nsecs();
+#else
+        ticks = 1;
+#endif
+        while(ticks > 0){
+                do_IRQ(TIMER_IRQ, regs);
+                ticks--;
+        }
+}
+
+static DEFINE_SPINLOCK(timer_spinlock);
+
+static unsigned long long local_offset = 0;
+
+static inline unsigned long long get_time(void)
+{
+        unsigned long long nsecs;
+        unsigned long flags;
+
+        spin_lock_irqsave(&timer_spinlock, flags);
+        nsecs = os_nsecs();
+        nsecs += local_offset;
+        spin_unlock_irqrestore(&timer_spinlock, flags);
+
+        return nsecs;
+}
+
+irqreturn_t um_timer(int irq, void *dev, struct pt_regs *regs)
+{
+        unsigned long long nsecs;
+        unsigned long flags;
+
+        write_seqlock_irqsave(&xtime_lock, flags);
+
+        do_timer(regs);
+
+        nsecs = get_time() + local_offset;
+        xtime.tv_sec = nsecs / NSEC_PER_SEC;
+        xtime.tv_nsec = nsecs - xtime.tv_sec * NSEC_PER_SEC;
+
+        write_sequnlock_irqrestore(&xtime_lock, flags);
+
+        return IRQ_HANDLED;
+}
+
+static void register_timer(void)
+{
+        int err;
+
+        err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL);
+        if(err != 0)
+                printk(KERN_ERR "timer_init : request_irq failed - "
+                       "errno = %d\n", -err);
+
+        timer_irq_inited = 1;
+
+        user_time_init();
+}
+
+extern void (*late_time_init)(void);
+
+void time_init(void)
+{
+        long long nsecs;
+
+        nsecs = os_nsecs();
+        set_normalized_timespec(&wall_to_monotonic, -nsecs / BILLION,
+                                -nsecs % BILLION);
+        late_time_init = register_timer;
+}
+
+void do_gettimeofday(struct timeval *tv)
+{
+        unsigned long long nsecs = get_time();
+
+        tv->tv_sec = nsecs / NSEC_PER_SEC;
+        /* Careful about calculations here - this was originally done as
+         * (nsecs - tv->tv_sec * NSEC_PER_SEC) / NSEC_PER_USEC
+         * which gave bogus (> 1000000) values.  Dunno why, suspect gcc
+         * (4.0.0) miscompiled it, or there's a subtle 64/32-bit conversion
+         * problem that I missed.
+         */
+        nsecs -= tv->tv_sec * NSEC_PER_SEC;
+        tv->tv_usec = (unsigned long) nsecs / NSEC_PER_USEC;
+}
+
+static inline void set_time(unsigned long long nsecs)
+{
+        unsigned long long now;
+        unsigned long flags;
+
+        spin_lock_irqsave(&timer_spinlock, flags);
+        now = os_nsecs();
+        local_offset = nsecs - now;
+        spin_unlock_irqrestore(&timer_spinlock, flags);
+
+        clock_was_set();
+}
+
+int do_settimeofday(struct timespec *tv)
+{
+        set_time((unsigned long long) tv->tv_sec * NSEC_PER_SEC + tv->tv_nsec);
+
+        return 0;
+}
+
+void timer_handler(int sig, union uml_pt_regs *regs)
+{
+        local_irq_disable();
+        irq_enter();
+        update_process_times(CHOOSE_MODE(
+                             (UPT_SC(regs) && user_context(UPT_SP(regs))),
+                             (regs)->skas.is_user));
+        irq_exit();
+        local_irq_enable();
+        if(current_thread->cpu == 0)
+                timer_irq(regs);
+}