diff options
Diffstat (limited to 'arch/um/kernel/time.c')
| -rw-r--r-- | arch/um/kernel/time.c | 182 |
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 00000000000..552ca1cb984 --- /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); +} |