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 "mode.h" 22 #include "os.h" 23 24 int hz(void) 25 { 26 return(HZ); 27 } 28 29 /* 30 * Scheduler clock - returns current time in nanosec units. 31 */ 32 unsigned long long sched_clock(void) 33 { 34 return (unsigned long long)jiffies_64 * (1000000000 / HZ); 35 } 36 37 #ifdef CONFIG_UML_REAL_TIME_CLOCK 38 static unsigned long long prev_nsecs[NR_CPUS]; 39 static long long delta[NR_CPUS]; /* Deviation per interval */ 40 #endif 41 42 void timer_irq(union uml_pt_regs *regs) 43 { 44 unsigned long long ticks = 0; 45 #ifdef CONFIG_UML_REAL_TIME_CLOCK 46 int c = cpu(); 47 if(prev_nsecs[c]){ 48 /* We've had 1 tick */ 49 unsigned long long nsecs = os_nsecs(); 50 51 delta[c] += nsecs - prev_nsecs[c]; 52 prev_nsecs[c] = nsecs; 53 54 /* Protect against the host clock being set backwards */ 55 if(delta[c] < 0) 56 delta[c] = 0; 57 58 ticks += (delta[c] * HZ) / BILLION; 59 delta[c] -= (ticks * BILLION) / HZ; 60 } 61 else prev_nsecs[c] = os_nsecs(); 62 #else 63 ticks = 1; 64 #endif 65 while(ticks > 0){ 66 do_IRQ(TIMER_IRQ, regs); 67 ticks--; 68 } 69 } 70 71 /* Protects local_offset */ 72 static DEFINE_SPINLOCK(timer_spinlock); 73 static unsigned long long local_offset = 0; 74 75 static inline unsigned long long get_time(void) 76 { 77 unsigned long long nsecs; 78 unsigned long flags; 79 80 spin_lock_irqsave(&timer_spinlock, flags); 81 nsecs = os_nsecs(); 82 nsecs += local_offset; 83 spin_unlock_irqrestore(&timer_spinlock, flags); 84 85 return nsecs; 86 } 87 88 irqreturn_t um_timer(int irq, void *dev) 89 { 90 unsigned long long nsecs; 91 unsigned long flags; 92 93 write_seqlock_irqsave(&xtime_lock, flags); 94 95 do_timer(1); 96 97 #ifdef CONFIG_UML_REAL_TIME_CLOCK 98 nsecs = get_time(); 99 #else 100 nsecs = (unsigned long long) xtime.tv_sec * BILLION + xtime.tv_nsec + 101 BILLION / HZ; 102 #endif 103 xtime.tv_sec = nsecs / NSEC_PER_SEC; 104 xtime.tv_nsec = nsecs - xtime.tv_sec * NSEC_PER_SEC; 105 106 write_sequnlock_irqrestore(&xtime_lock, flags); 107 108 return IRQ_HANDLED; 109 } 110 111 static void register_timer(void) 112 { 113 int err; 114 115 err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL); 116 if(err != 0) 117 printk(KERN_ERR "register_timer : request_irq failed - " 118 "errno = %d\n", -err); 119 120 err = set_interval(1); 121 if(err != 0) 122 printk(KERN_ERR "register_timer : set_interval failed - " 123 "errno = %d\n", -err); 124 } 125 126 extern void (*late_time_init)(void); 127 128 void time_init(void) 129 { 130 long long nsecs; 131 132 nsecs = os_nsecs(); 133 set_normalized_timespec(&wall_to_monotonic, -nsecs / BILLION, 134 -nsecs % BILLION); 135 set_normalized_timespec(&xtime, nsecs / BILLION, nsecs % BILLION); 136 late_time_init = register_timer; 137 } 138 139 void do_gettimeofday(struct timeval *tv) 140 { 141 #ifdef CONFIG_UML_REAL_TIME_CLOCK 142 unsigned long long nsecs = get_time(); 143 #else 144 unsigned long long nsecs = (unsigned long long) xtime.tv_sec * BILLION + 145 xtime.tv_nsec; 146 #endif 147 tv->tv_sec = nsecs / NSEC_PER_SEC; 148 /* Careful about calculations here - this was originally done as 149 * (nsecs - tv->tv_sec * NSEC_PER_SEC) / NSEC_PER_USEC 150 * which gave bogus (> 1000000) values. Dunno why, suspect gcc 151 * (4.0.0) miscompiled it, or there's a subtle 64/32-bit conversion 152 * problem that I missed. 153 */ 154 nsecs -= tv->tv_sec * NSEC_PER_SEC; 155 tv->tv_usec = (unsigned long) nsecs / NSEC_PER_USEC; 156 } 157 158 static inline void set_time(unsigned long long nsecs) 159 { 160 unsigned long long now; 161 unsigned long flags; 162 163 spin_lock_irqsave(&timer_spinlock, flags); 164 now = os_nsecs(); 165 local_offset = nsecs - now; 166 spin_unlock_irqrestore(&timer_spinlock, flags); 167 168 clock_was_set(); 169 } 170 171 int do_settimeofday(struct timespec *tv) 172 { 173 set_time((unsigned long long) tv->tv_sec * NSEC_PER_SEC + tv->tv_nsec); 174 175 return 0; 176 } 177 178 void timer_handler(int sig, union uml_pt_regs *regs) 179 { 180 if(current_thread->cpu == 0) 181 timer_irq(regs); 182 local_irq_disable(); 183 irq_enter(); 184 update_process_times(CHOOSE_MODE( 185 (UPT_SC(regs) && user_context(UPT_SP(regs))), 186 (regs)->skas.is_user)); 187 irq_exit(); 188 local_irq_enable(); 189 } 190