linux/kernel/time/itimer.c
Thomas Gleixner 2456e85535 ktime: Get rid of the union
ktime is a union because the initial implementation stored the time in
scalar nanoseconds on 64 bit machine and in a endianess optimized timespec
variant for 32bit machines. The Y2038 cleanup removed the timespec variant
and switched everything to scalar nanoseconds. The union remained, but
become completely pointless.

Get rid of the union and just keep ktime_t as simple typedef of type s64.

The conversion was done with coccinelle and some manual mopping up.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
2016-12-25 17:21:22 +01:00

315 lines
7.5 KiB
C

/*
* linux/kernel/itimer.c
*
* Copyright (C) 1992 Darren Senn
*/
/* These are all the functions necessary to implement itimers */
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/syscalls.h>
#include <linux/time.h>
#include <linux/posix-timers.h>
#include <linux/hrtimer.h>
#include <trace/events/timer.h>
#include <linux/uaccess.h>
/**
* itimer_get_remtime - get remaining time for the timer
*
* @timer: the timer to read
*
* Returns the delta between the expiry time and now, which can be
* less than zero or 1usec for an pending expired timer
*/
static struct timeval itimer_get_remtime(struct hrtimer *timer)
{
ktime_t rem = __hrtimer_get_remaining(timer, true);
/*
* Racy but safe: if the itimer expires after the above
* hrtimer_get_remtime() call but before this condition
* then we return 0 - which is correct.
*/
if (hrtimer_active(timer)) {
if (rem <= 0)
rem = NSEC_PER_USEC;
} else
rem = 0;
return ktime_to_timeval(rem);
}
static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
struct itimerval *const value)
{
cputime_t cval, cinterval;
struct cpu_itimer *it = &tsk->signal->it[clock_id];
spin_lock_irq(&tsk->sighand->siglock);
cval = it->expires;
cinterval = it->incr;
if (cval) {
struct task_cputime cputime;
cputime_t t;
thread_group_cputimer(tsk, &cputime);
if (clock_id == CPUCLOCK_PROF)
t = cputime.utime + cputime.stime;
else
/* CPUCLOCK_VIRT */
t = cputime.utime;
if (cval < t)
/* about to fire */
cval = cputime_one_jiffy;
else
cval = cval - t;
}
spin_unlock_irq(&tsk->sighand->siglock);
cputime_to_timeval(cval, &value->it_value);
cputime_to_timeval(cinterval, &value->it_interval);
}
int do_getitimer(int which, struct itimerval *value)
{
struct task_struct *tsk = current;
switch (which) {
case ITIMER_REAL:
spin_lock_irq(&tsk->sighand->siglock);
value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
value->it_interval =
ktime_to_timeval(tsk->signal->it_real_incr);
spin_unlock_irq(&tsk->sighand->siglock);
break;
case ITIMER_VIRTUAL:
get_cpu_itimer(tsk, CPUCLOCK_VIRT, value);
break;
case ITIMER_PROF:
get_cpu_itimer(tsk, CPUCLOCK_PROF, value);
break;
default:
return(-EINVAL);
}
return 0;
}
SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
{
int error = -EFAULT;
struct itimerval get_buffer;
if (value) {
error = do_getitimer(which, &get_buffer);
if (!error &&
copy_to_user(value, &get_buffer, sizeof(get_buffer)))
error = -EFAULT;
}
return error;
}
/*
* The timer is automagically restarted, when interval != 0
*/
enum hrtimer_restart it_real_fn(struct hrtimer *timer)
{
struct signal_struct *sig =
container_of(timer, struct signal_struct, real_timer);
trace_itimer_expire(ITIMER_REAL, sig->leader_pid, 0);
kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
return HRTIMER_NORESTART;
}
static inline u32 cputime_sub_ns(cputime_t ct, s64 real_ns)
{
struct timespec ts;
s64 cpu_ns;
cputime_to_timespec(ct, &ts);
cpu_ns = timespec_to_ns(&ts);
return (cpu_ns <= real_ns) ? 0 : cpu_ns - real_ns;
}
static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
const struct itimerval *const value,
struct itimerval *const ovalue)
{
cputime_t cval, nval, cinterval, ninterval;
s64 ns_ninterval, ns_nval;
u32 error, incr_error;
struct cpu_itimer *it = &tsk->signal->it[clock_id];
nval = timeval_to_cputime(&value->it_value);
ns_nval = timeval_to_ns(&value->it_value);
ninterval = timeval_to_cputime(&value->it_interval);
ns_ninterval = timeval_to_ns(&value->it_interval);
error = cputime_sub_ns(nval, ns_nval);
incr_error = cputime_sub_ns(ninterval, ns_ninterval);
spin_lock_irq(&tsk->sighand->siglock);
cval = it->expires;
cinterval = it->incr;
if (cval || nval) {
if (nval > 0)
nval += cputime_one_jiffy;
set_process_cpu_timer(tsk, clock_id, &nval, &cval);
}
it->expires = nval;
it->incr = ninterval;
it->error = error;
it->incr_error = incr_error;
trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
spin_unlock_irq(&tsk->sighand->siglock);
if (ovalue) {
cputime_to_timeval(cval, &ovalue->it_value);
cputime_to_timeval(cinterval, &ovalue->it_interval);
}
}
/*
* Returns true if the timeval is in canonical form
*/
#define timeval_valid(t) \
(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
{
struct task_struct *tsk = current;
struct hrtimer *timer;
ktime_t expires;
/*
* Validate the timevals in value.
*/
if (!timeval_valid(&value->it_value) ||
!timeval_valid(&value->it_interval))
return -EINVAL;
switch (which) {
case ITIMER_REAL:
again:
spin_lock_irq(&tsk->sighand->siglock);
timer = &tsk->signal->real_timer;
if (ovalue) {
ovalue->it_value = itimer_get_remtime(timer);
ovalue->it_interval
= ktime_to_timeval(tsk->signal->it_real_incr);
}
/* We are sharing ->siglock with it_real_fn() */
if (hrtimer_try_to_cancel(timer) < 0) {
spin_unlock_irq(&tsk->sighand->siglock);
goto again;
}
expires = timeval_to_ktime(value->it_value);
if (expires != 0) {
tsk->signal->it_real_incr =
timeval_to_ktime(value->it_interval);
hrtimer_start(timer, expires, HRTIMER_MODE_REL);
} else
tsk->signal->it_real_incr = 0;
trace_itimer_state(ITIMER_REAL, value, 0);
spin_unlock_irq(&tsk->sighand->siglock);
break;
case ITIMER_VIRTUAL:
set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue);
break;
case ITIMER_PROF:
set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue);
break;
default:
return -EINVAL;
}
return 0;
}
#ifdef __ARCH_WANT_SYS_ALARM
/**
* alarm_setitimer - set alarm in seconds
*
* @seconds: number of seconds until alarm
* 0 disables the alarm
*
* Returns the remaining time in seconds of a pending timer or 0 when
* the timer is not active.
*
* On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
* negative timeval settings which would cause immediate expiry.
*/
static unsigned int alarm_setitimer(unsigned int seconds)
{
struct itimerval it_new, it_old;
#if BITS_PER_LONG < 64
if (seconds > INT_MAX)
seconds = INT_MAX;
#endif
it_new.it_value.tv_sec = seconds;
it_new.it_value.tv_usec = 0;
it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
do_setitimer(ITIMER_REAL, &it_new, &it_old);
/*
* We can't return 0 if we have an alarm pending ... And we'd
* better return too much than too little anyway
*/
if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) ||
it_old.it_value.tv_usec >= 500000)
it_old.it_value.tv_sec++;
return it_old.it_value.tv_sec;
}
/*
* For backwards compatibility? This can be done in libc so Alpha
* and all newer ports shouldn't need it.
*/
SYSCALL_DEFINE1(alarm, unsigned int, seconds)
{
return alarm_setitimer(seconds);
}
#endif
SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
struct itimerval __user *, ovalue)
{
struct itimerval set_buffer, get_buffer;
int error;
if (value) {
if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
return -EFAULT;
} else {
memset(&set_buffer, 0, sizeof(set_buffer));
printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
" Misfeature support will be removed\n",
current->comm);
}
error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
if (error || !ovalue)
return error;
if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
return -EFAULT;
return 0;
}