/*
* Implement CPU time clocks for the POSIX clock interface.
*/
#include <linux/sched.h>
#include <linux/posix-timers.h>
#include <linux/errno.h>
#include <linux/math64.h>
#include <asm/uaccess.h>
#include <linux/kernel_stat.h>
#include <trace/events/timer.h>
#include <linux/random.h>
#include <linux/tick.h>
#include <linux/workqueue.h>
/*
* Called after updating RLIMIT_CPU to run cpu timer and update
* tsk->signal->cputime_expires expiration cache if necessary. Needs
* siglock protection since other code may update expiration cache as
* well.
*/
void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
{
cputime_t cputime = secs_to_cputime(rlim_new);
spin_lock_irq(&task->sighand->siglock);
set_process_cpu_timer(task, CPUCLOCK_PROF, &cputime, NULL);
spin_unlock_irq(&task->sighand->siglock);
}
static int check_clock(const clockid_t which_clock)
{
int error = 0;
struct task_struct *p;
const pid_t pid = CPUCLOCK_PID(which_clock);
if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
return -EINVAL;
if (pid == 0)
return 0;
rcu_read_lock();
p = find_task_by_vpid(pid);
if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
same_thread_group(p, current) : has_group_leader_pid(p))) {
error = -EINVAL;
}
rcu_read_unlock();
return error;
}
static inline union cpu_time_count
timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
{
union cpu_time_count ret;
ret.sched = 0; /* high half always zero when .cpu used */
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
} else {
ret.cpu = timespec_to_cputime(tp);
}
return ret;
}
static void sample_to_timespec(const clockid_t which_clock,
union cpu_time_count cpu,
struct timespec *tp)
{
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
*tp = ns_to_timespec(cpu.sched);
else
cputime_to_timespec(cpu.cpu, tp);
}
static inline int cpu_time_before(const clockid_t which_clock,
union cpu_time_count now,
union cpu_time_count then)
{
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
return now.sched < then.sched;
} else {
return now.cpu < then.cpu;
}
}
static inline void cpu_time_add(const clockid_t which_clock,
union cpu_time_count *acc,
union cpu_time_count val)
{
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
acc->sched += val.sched;
} else {
acc->cpu += val.cpu;
}
}
static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
union cpu_time_count a,
union cpu_time_count b)
{
if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
a.sched -= b.sched;
} else {
a.cpu -= b.c
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