arch/um/kernel/time_kern.c

   1 /*
   2  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/kernel.h"
   7 #include "linux/module.h"
   8 #include "linux/unistd.h"
   9 #include "linux/stddef.h"
  10 #include "linux/spinlock.h"
  11 #include "linux/time.h"
  12 #include "linux/sched.h"
  13 #include "linux/interrupt.h"
  14 #include "linux/init.h"
  15 #include "linux/delay.h"
  16 #include "asm/irq.h"
  17 #include "asm/param.h"
  18 #include "asm/current.h"
  19 #include "kern_util.h"
  20 #include "user_util.h"
  21 #include "time_user.h"
  22 #include "mode.h"
  23 #include "os.h"
  24
  25 u64 jiffies_64 = INITIAL_JIFFIES;
  26
  27 EXPORT_SYMBOL(jiffies_64);
  28
  29 int hz(void)
  30 {
  31         return(HZ);
  32 }
  33
  34 /*
  35  * Scheduler clock - returns current time in nanosec units.
  36  */
  37 unsigned long long sched_clock(void)
  38 {
  39         return (unsigned long long)jiffies_64 * (1000000000 / HZ);
  40 }
  41
  42 /* Changed at early boot */
  43 int timer_irq_inited = 0;
  44
  45 static int first_tick;
  46 static unsigned long long prev_usecs;
  47 #ifdef CONFIG_UML_REAL_TIME_CLOCK
  48 static long long delta;                 /* Deviation per interval */
  49 #endif
  50
  51 void timer_irq(union uml_pt_regs *regs)
  52 {
  53         unsigned long long ticks = 0;
  54
  55         if(!timer_irq_inited){
  56                 /* This is to ensure that ticks don't pile up when
  57                  * the timer handler is suspended */
  58                 first_tick = 0;
  59                 return;
  60         }
  61
  62         if(first_tick){
  63 #ifdef CONFIG_UML_REAL_TIME_CLOCK
  64                 /* We've had 1 tick */
  65                 unsigned long long usecs = os_usecs();
  66
  67                 delta += usecs - prev_usecs;
  68                 prev_usecs = usecs;
  69
  70                 /* Protect against the host clock being set backwards */
  71                 if(delta < 0)
  72                         delta = 0;
  73
  74                 ticks += (delta * HZ) / MILLION;
  75                 delta -= (ticks * MILLION) / HZ;
  76 #else
  77                 ticks = 1;
  78 #endif
  79         }
  80         else {
  81                 prev_usecs = os_usecs();
  82                 first_tick = 1;
  83         }
  84
  85         while(ticks > 0){
  86                 do_IRQ(TIMER_IRQ, regs);
  87                 ticks--;
  88         }
  89 }
  90
  91 void boot_timer_handler(int sig)
  92 {
  93         struct pt_regs regs;
  94
  95         CHOOSE_MODE((void)
  96                     (UPT_SC(&regs.regs) = (struct sigcontext *) (&sig + 1)),
  97                     (void) (regs.regs.skas.is_user = 0));
  98         do_timer(&regs);
  99 }
 100
 101 irqreturn_t um_timer(int irq, void *dev, struct pt_regs *regs)
 102 {
 103         unsigned long flags;
 104
 105         do_timer(regs);
 106         write_seqlock_irqsave(&xtime_lock, flags);
 107         timer();
 108         write_sequnlock_irqrestore(&xtime_lock, flags);
 109         return(IRQ_HANDLED);
 110 }
 111
 112 long um_time(int __user *tloc)
 113 {
 114         struct timeval now;
 115
 116         do_gettimeofday(&now);
 117         if (tloc) {
 118                 if (put_user(now.tv_sec, tloc))
 119                         now.tv_sec = -EFAULT;
 120         }
 121         return now.tv_sec;
 122 }
 123
 124 long um_stime(int __user *tptr)
 125 {
 126         int value;
 127         struct timespec new;
 128
 129         if (get_user(value, tptr))
 130                 return -EFAULT;
 131         new.tv_sec = value;
 132         new.tv_nsec = 0;
 133         do_settimeofday(&new);
 134         return 0;
 135 }
 136
 137 void timer_handler(int sig, union uml_pt_regs *regs)
 138 {
 139         local_irq_disable();
 140         irq_enter();
 141         update_process_times(CHOOSE_MODE(user_context(UPT_SP(regs)),
 142                                          (regs)->skas.is_user));
 143         irq_exit();
 144         local_irq_enable();
 145         if(current_thread->cpu == 0)
 146                 timer_irq(regs);
 147 }
 148
 149 static DEFINE_SPINLOCK(timer_spinlock);
 150
 151 unsigned long time_lock(void)
 152 {
 153         unsigned long flags;
 154
 155         spin_lock_irqsave(&timer_spinlock, flags);
 156         return(flags);
 157 }
 158
 159 void time_unlock(unsigned long flags)
 160 {
 161         spin_unlock_irqrestore(&timer_spinlock, flags);
 162 }
 163
 164 int __init timer_init(void)
 165 {
 166         int err;
 167
 168         user_time_init();
 169         err = request_irq(TIMER_IRQ, um_timer, SA_INTERRUPT, "timer", NULL);
 170         if(err != 0)
 171                 printk(KERN_ERR "timer_init : request_irq failed - "
 172                        "errno = %d\n", -err);
 173         timer_irq_inited = 1;
 174         return(0);
 175 }
 176
 177 __initcall(timer_init);
 178
 179 /*
 180  * Overrides for Emacs so that we follow Linus's tabbing style.
 181  * Emacs will notice this stuff at the end of the file and automatically
 182  * adjust the settings for this buffer only.  This must remain at the end
 183  * of the file.
 184  * ---------------------------------------------------------------------------
 185  * Local variables:
 186  * c-file-style: "linux"
 187  * End:
 188  */