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.
bigtime_t	get_real_time (void)
	Returns the number of microseconds since 1970-01-01.
bigtime_t	get_idle_time (int nProcessor)
	Returns the total idle time for the given CPU.
int	sys_get_raw_system_time (bigtime_t *pRes)
	Returns the time elapsed since last system boot, in microseconds.
int	sys_get_raw_real_time (bigtime_t *pRes)
	Returns the number of microseconds since 1970-01-01.
int	sys_get_raw_idle_time (bigtime_t *pRes, int nProcessor)
	Returns the total idle time for the given CPU, in microseconds.
int	sys_set_real_time (uint32 nTimeLow, uint32 nTimeHigh)
	Sets the system clock to a new time.
void	TimerInterrupt (SysCallRegs_s *psRegs)
	This is the timer interrupt handler, called INT_FREQ times per second.
void	start_timer_int (void)
	Initializes the PIT timers.
void	get_cmos_time (void)
	Sets the system time from the battery-backed CMOS clock.
Variables
int	g_bNeedSchedule
	If true, the scheduler will be called when returning from syscall.

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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.

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Function Documentation

void get_cmos_time

(

void

)

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

See also:

kernel_init()

Author:

Kurt Skauen ([email protected])

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 ([email protected])

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 ([email protected])

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 ([email protected])

void start_timer_int

(

void

)

Initializes the PIT timers.

See also:

kernel_init()

Author:

Kurt Skauen ([email protected])

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 ([email protected])

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 ([email protected])

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 ([email protected])

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 ([email protected])

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 ([email protected])

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