timer.c File Reference

This file contains the timer interrupt handler and functions to return the system time (time elapsed since boot), real time (since 1970-01-01), and per-CPU idle time. More...

Functions
	SEQ_LOCK (g_sTimerSeqLock,"timer_slock")
	SPIN_LOCK (g_sPitTimerSpinLock,"i8253_slock")
bigtime_t	get_system_time (void)
	Returns the time elapsed since last system boot. More...
bigtime_t	get_real_time (void)
	Returns the number of microseconds since 1970-01-01. More...
bigtime_t	get_idle_time (int nProcessor)
	Returns the total idle time for the given CPU. More...
int	sys_get_raw_system_time (bigtime_t *pRes)
	Returns the time elapsed since last system boot, in microseconds. More...
int	sys_get_raw_real_time (bigtime_t *pRes)
	Returns the number of microseconds since 1970-01-01. More...
int	sys_get_raw_idle_time (bigtime_t *pRes, int nProcessor)
	Returns the total idle time for the given CPU, in microseconds. More...
int	sys_set_real_time (uint32 nTimeLow, uint32 nTimeHigh)
	Sets the system clock to a new time. More...
void	TimerInterrupt (SysCallRegs_s *psRegs)
	This is the timer interrupt handler, called INT_FREQ times per second. More...
void	start_timer_int (void)
	Initializes the PIT timers. More...
void	get_cmos_time (void)
	Sets the system time from the battery-backed CMOS clock. More...

Variables
int	g_bNeedSchedule
	If true, the scheduler will be called when returning from syscall. More...

Detailed Description

This file contains the timer interrupt handler and functions to return the system time (time elapsed since boot), real time (since 1970-01-01), and per-CPU idle time.

All time values are returned in microseconds.

Function Documentation

void get_cmos_time

(

void

)

Sets the system time from the battery-backed CMOS clock.

See Also

kernel_init()

Author

Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

bigtime_t get_idle_time

(

int

nProcessor

)

Returns the total idle time for the given CPU.

Parameters

nProcessor

the processor for which to return the idle time.

Returns

Idle time for the given CPU, in microseconds.

Author

Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

bigtime_t get_real_time

(

void

)

Returns the number of microseconds since 1970-01-01.

Returns

The number of microseconds since 1970-01-01.

Author

Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

bigtime_t get_system_time

(

void

)

Returns the time elapsed since last system boot.

Returns

Time since last system boot, in microseconds.

Author

Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

void start_timer_int

(

void

)

Initializes the PIT timers.

See Also

kernel_init()

Author

Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

int sys_get_raw_idle_time	(	bigtime_t *	pRes,
		int	nProcessor
	)

Returns the total idle time for the given CPU, in microseconds.

Parameters

pRes	a pointer to the bigtime_t in which to store the CPU idle time.
nProcessor	the processor for which to return the idle time.

Author

Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

int sys_get_raw_real_time

(

bigtime_t *

pRes

)

Returns the number of microseconds since 1970-01-01.

Parameters

pRes	a pointer to the bigtime_t in which to store the current time.

Author

Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

int sys_get_raw_system_time

(

bigtime_t *

pRes

)

Returns the time elapsed since last system boot, in microseconds.

Parameters

pRes	a pointer to the bigtime_t in which to store the system time.

Author

Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

int sys_set_real_time	(	uint32	nTimeLow,
		uint32	nTimeHigh
	)

Sets the system clock to a new time.

Does not set the RTC.

Parameters

nTimeLow	the low 32 bits of the new system time, in microseconds since 1970-01-01.
nTimeHigh	the high 32 bits of the new system time

Returns

Always returns 0.

Attention

Missing check for sufficient privileges to set the system clock.

Author

Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

void TimerInterrupt

(

SysCallRegs_s *

psRegs

)

This is the timer interrupt handler, called INT_FREQ times per second.

It updates the system time and calls functions send_timer_signals() and wake_up_sleepers(). If there is no APIC present, Schedule() is also called here; otherwise, Schedule() is called for each CPU via do_smp_preempt(), which is triggered by the APIC timer.

Parameters

dummy

unused.

See Also

idle_loop()

Author

Kurt Skauen (kurt@.nosp@m.athe.nosp@m.os.cx)

Variable Documentation

int g_bNeedSchedule

If true, the scheduler will be called when returning from syscall.