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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /kernel/time/itimer.c | |
parent | Initial commit. (diff) | |
download | linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'kernel/time/itimer.c')
-rw-r--r-- | kernel/time/itimer.c | 403 |
1 files changed, 403 insertions, 0 deletions
diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c new file mode 100644 index 000000000..00629e658 --- /dev/null +++ b/kernel/time/itimer.c @@ -0,0 +1,403 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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/sched/signal.h> +#include <linux/sched/cputime.h> +#include <linux/posix-timers.h> +#include <linux/hrtimer.h> +#include <trace/events/timer.h> +#include <linux/compat.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 timespec64 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_timespec64(rem); +} + +static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, + struct itimerspec64 *const value) +{ + u64 val, interval; + struct cpu_itimer *it = &tsk->signal->it[clock_id]; + + spin_lock_irq(&tsk->sighand->siglock); + + val = it->expires; + interval = it->incr; + if (val) { + u64 t, samples[CPUCLOCK_MAX]; + + thread_group_sample_cputime(tsk, samples); + t = samples[clock_id]; + + if (val < t) + /* about to fire */ + val = TICK_NSEC; + else + val -= t; + } + + spin_unlock_irq(&tsk->sighand->siglock); + + value->it_value = ns_to_timespec64(val); + value->it_interval = ns_to_timespec64(interval); +} + +static int do_getitimer(int which, struct itimerspec64 *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_timespec64(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; +} + +static int put_itimerval(struct __kernel_old_itimerval __user *o, + const struct itimerspec64 *i) +{ + struct __kernel_old_itimerval v; + + v.it_interval.tv_sec = i->it_interval.tv_sec; + v.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC; + v.it_value.tv_sec = i->it_value.tv_sec; + v.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC; + return copy_to_user(o, &v, sizeof(struct __kernel_old_itimerval)) ? -EFAULT : 0; +} + + +SYSCALL_DEFINE2(getitimer, int, which, struct __kernel_old_itimerval __user *, value) +{ + struct itimerspec64 get_buffer; + int error = do_getitimer(which, &get_buffer); + + if (!error && put_itimerval(value, &get_buffer)) + error = -EFAULT; + return error; +} + +#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA) +struct old_itimerval32 { + struct old_timeval32 it_interval; + struct old_timeval32 it_value; +}; + +static int put_old_itimerval32(struct old_itimerval32 __user *o, + const struct itimerspec64 *i) +{ + struct old_itimerval32 v32; + + v32.it_interval.tv_sec = i->it_interval.tv_sec; + v32.it_interval.tv_usec = i->it_interval.tv_nsec / NSEC_PER_USEC; + v32.it_value.tv_sec = i->it_value.tv_sec; + v32.it_value.tv_usec = i->it_value.tv_nsec / NSEC_PER_USEC; + return copy_to_user(o, &v32, sizeof(struct old_itimerval32)) ? -EFAULT : 0; +} + +COMPAT_SYSCALL_DEFINE2(getitimer, int, which, + struct old_itimerval32 __user *, value) +{ + struct itimerspec64 get_buffer; + int error = do_getitimer(which, &get_buffer); + + if (!error && put_old_itimerval32(value, &get_buffer)) + error = -EFAULT; + return error; +} +#endif + +/* + * 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); + struct pid *leader_pid = sig->pids[PIDTYPE_TGID]; + + trace_itimer_expire(ITIMER_REAL, leader_pid, 0); + kill_pid_info(SIGALRM, SEND_SIG_PRIV, leader_pid); + + return HRTIMER_NORESTART; +} + +static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, + const struct itimerspec64 *const value, + struct itimerspec64 *const ovalue) +{ + u64 oval, nval, ointerval, ninterval; + struct cpu_itimer *it = &tsk->signal->it[clock_id]; + + nval = timespec64_to_ns(&value->it_value); + ninterval = timespec64_to_ns(&value->it_interval); + + spin_lock_irq(&tsk->sighand->siglock); + + oval = it->expires; + ointerval = it->incr; + if (oval || nval) { + if (nval > 0) + nval += TICK_NSEC; + set_process_cpu_timer(tsk, clock_id, &nval, &oval); + } + it->expires = nval; + it->incr = ninterval; + trace_itimer_state(clock_id == CPUCLOCK_VIRT ? + ITIMER_VIRTUAL : ITIMER_PROF, value, nval); + + spin_unlock_irq(&tsk->sighand->siglock); + + if (ovalue) { + ovalue->it_value = ns_to_timespec64(oval); + ovalue->it_interval = ns_to_timespec64(ointerval); + } +} + +/* + * 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)) + +static int do_setitimer(int which, struct itimerspec64 *value, + struct itimerspec64 *ovalue) +{ + struct task_struct *tsk = current; + struct hrtimer *timer; + ktime_t expires; + + 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_timespec64(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); + hrtimer_cancel_wait_running(timer); + goto again; + } + expires = timespec64_to_ktime(value->it_value); + if (expires != 0) { + tsk->signal->it_real_incr = + timespec64_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 CONFIG_SECURITY_SELINUX +void clear_itimer(void) +{ + struct itimerspec64 v = {}; + int i; + + for (i = 0; i < 3; i++) + do_setitimer(i, &v, NULL); +} +#endif + +#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 itimerspec64 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_nsec = 0; + it_new.it_interval.tv_sec = it_new.it_interval.tv_nsec = 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_nsec) || + it_old.it_value.tv_nsec >= (NSEC_PER_SEC / 2)) + 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 + +static int get_itimerval(struct itimerspec64 *o, const struct __kernel_old_itimerval __user *i) +{ + struct __kernel_old_itimerval v; + + if (copy_from_user(&v, i, sizeof(struct __kernel_old_itimerval))) + return -EFAULT; + + /* Validate the timevals in value. */ + if (!timeval_valid(&v.it_value) || + !timeval_valid(&v.it_interval)) + return -EINVAL; + + o->it_interval.tv_sec = v.it_interval.tv_sec; + o->it_interval.tv_nsec = v.it_interval.tv_usec * NSEC_PER_USEC; + o->it_value.tv_sec = v.it_value.tv_sec; + o->it_value.tv_nsec = v.it_value.tv_usec * NSEC_PER_USEC; + return 0; +} + +SYSCALL_DEFINE3(setitimer, int, which, struct __kernel_old_itimerval __user *, value, + struct __kernel_old_itimerval __user *, ovalue) +{ + struct itimerspec64 set_buffer, get_buffer; + int error; + + if (value) { + error = get_itimerval(&set_buffer, value); + if (error) + return error; + } 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 (put_itimerval(ovalue, &get_buffer)) + return -EFAULT; + return 0; +} + +#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA) +static int get_old_itimerval32(struct itimerspec64 *o, const struct old_itimerval32 __user *i) +{ + struct old_itimerval32 v32; + + if (copy_from_user(&v32, i, sizeof(struct old_itimerval32))) + return -EFAULT; + + /* Validate the timevals in value. */ + if (!timeval_valid(&v32.it_value) || + !timeval_valid(&v32.it_interval)) + return -EINVAL; + + o->it_interval.tv_sec = v32.it_interval.tv_sec; + o->it_interval.tv_nsec = v32.it_interval.tv_usec * NSEC_PER_USEC; + o->it_value.tv_sec = v32.it_value.tv_sec; + o->it_value.tv_nsec = v32.it_value.tv_usec * NSEC_PER_USEC; + return 0; +} + +COMPAT_SYSCALL_DEFINE3(setitimer, int, which, + struct old_itimerval32 __user *, value, + struct old_itimerval32 __user *, ovalue) +{ + struct itimerspec64 set_buffer, get_buffer; + int error; + + if (value) { + error = get_old_itimerval32(&set_buffer, value); + if (error) + return error; + } 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 (put_old_itimerval32(ovalue, &get_buffer)) + return -EFAULT; + return 0; +} +#endif |