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