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 "linux/hrtimer.h" 17 #include "asm/irq.h" 18 #include "asm/param.h" 19 #include "asm/current.h" 20 #include "kern_util.h" 21 #include "user_util.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 unsigned long long prev_nsecs; 42 #ifdef CONFIG_UML_REAL_TIME_CLOCK 43 static long long delta; /* Deviation per interval */ 44 #endif 45 46 void timer_irq(union uml_pt_regs *regs) 47 { 48 unsigned long long ticks = 0; 49 50 #ifdef CONFIG_UML_REAL_TIME_CLOCK 51 if(prev_nsecs){ 52 /* We've had 1 tick */ 53 unsigned long long nsecs = os_nsecs(); 54 55 delta += nsecs - prev_nsecs; 56 prev_nsecs = nsecs; 57 58 /* Protect against the host clock being set backwards */ 59 if(delta < 0) 60 delta = 0; 61 62 ticks += (delta * HZ) / BILLION; 63 delta -= (ticks * BILLION) / HZ; 64 } 65 else prev_nsecs = os_nsecs(); 66 #else 67 ticks = 1; 68 #endif 69 while(ticks > 0){ 70 do_IRQ(TIMER_IRQ, regs); 71 ticks--; 72 } 73 } 74 75 static DEFINE_SPINLOCK(timer_spinlock); 76 77 static unsigned long long local_offset = 0; 78 79 static inline unsigned long long get_time(void) 80 { 81 unsigned long long nsecs; 82 unsigned long flags; 83 84 spin_lock_irqsave(&timer_spinlock, flags); 85 nsecs = os_nsecs(); 86 nsecs += local_offset; 87 spin_unlock_irqrestore(&timer_spinlock, flags); 88 89 return nsecs; 90 } 91 92 irqreturn_t um_timer(int irq, void *dev, struct pt_regs *regs) 93 { 94 unsigned long long nsecs; 95 unsigned long flags; 96 97 write_seqlock_irqsave(&xtime_lock, flags); 98 99 do_timer(regs); 100 101 nsecs = get_time() + local_offset; 102 xtime.tv_sec = nsecs / NSEC_PER_SEC; 103 xtime.tv_nsec = nsecs - xtime.tv_sec * NSEC_PER_SEC; 104 105 write_sequnlock_irqrestore(&xtime_lock, flags); 106 107 return IRQ_HANDLED; 108 } 109 110 static void register_timer(void) 111 { 112 int err; 113 114 err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL); 115 if(err != 0) 116 printk(KERN_ERR "timer_init : request_irq failed - " 117 "errno = %d\n", -err); 118 119 timer_irq_inited = 1; 120 121 user_time_init(); 122 } 123 124 extern void (*late_time_init)(void); 125 126 void time_init(void) 127 { 128 long long nsecs; 129 130 nsecs = os_nsecs(); 131 set_normalized_timespec(&wall_to_monotonic, -nsecs / BILLION, 132 -nsecs % BILLION); 133 late_time_init = register_timer; 134 } 135 136 void do_gettimeofday(struct timeval *tv) 137 { 138 unsigned long long nsecs = get_time(); 139 140 tv->tv_sec = nsecs / NSEC_PER_SEC; 141 /* Careful about calculations here - this was originally done as 142 * (nsecs - tv->tv_sec * NSEC_PER_SEC) / NSEC_PER_USEC 143 * which gave bogus (> 1000000) values. Dunno why, suspect gcc 144 * (4.0.0) miscompiled it, or there's a subtle 64/32-bit conversion 145 * problem that I missed. 146 */ 147 nsecs -= tv->tv_sec * NSEC_PER_SEC; 148 tv->tv_usec = (unsigned long) nsecs / NSEC_PER_USEC; 149 } 150 151 static inline void set_time(unsigned long long nsecs) 152 { 153 unsigned long long now; 154 unsigned long flags; 155 156 spin_lock_irqsave(&timer_spinlock, flags); 157 now = os_nsecs(); 158 local_offset = nsecs - now; 159 spin_unlock_irqrestore(&timer_spinlock, flags); 160 161 clock_was_set(); 162 } 163 164 int do_settimeofday(struct timespec *tv) 165 { 166 set_time((unsigned long long) tv->tv_sec * NSEC_PER_SEC + tv->tv_nsec); 167 168 return 0; 169 } 170 171 void timer_handler(int sig, union uml_pt_regs *regs) 172 { 173 local_irq_disable(); 174 irq_enter(); 175 update_process_times(CHOOSE_MODE( 176 (UPT_SC(regs) && user_context(UPT_SP(regs))), 177 (regs)->skas.is_user)); 178 irq_exit(); 179 local_irq_enable(); 180 if(current_thread->cpu == 0) 181 timer_irq(regs); 182 } 183