From 6c5e9059692567740a4ee51530dffe51a4b9584d Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Fri, 21 Oct 2016 08:58:50 -0700 Subject: timers: Fix usleep_range() in the context of wake_up_process() Users of usleep_range() expect that it will _never_ return in less time than the minimum passed parameter. However, nothing in the code ensures this, when the sleeping task is woken by wake_up_process() or any other mechanism which can wake a task from uninterruptible state. Neither usleep_range() nor schedule_hrtimeout_range*() have any protection against wakeups. schedule_hrtimeout_range*() is designed this way despite the fact that the API documentation does not mention it. msleep() already has code to handle this case since it will loop as long as there was still time left. usleep_range() has no such loop, add it. Presumably this problem was not detected before because usleep_range() is only used in a few places and the function is mostly used in contexts which are not exposed to wakeups of any form. An effort was made to look for users relying on the old behavior by looking for usleep_range() in the same file as wake_up_process(). No problems were found by this search, though it is conceivable that someone could have put the sleep and wakeup in two different files. An effort was made to ask several upstream maintainers if they were aware of people relying on wake_up_process() to wake up usleep_range(). No maintainers were aware of that but they were aware of many people relying on usleep_range() never returning before the minimum. Reported-by: Tao Huang Signed-off-by: Douglas Anderson Cc: heiko@sntech.de Cc: broonie@kernel.org Cc: briannorris@chromium.org Cc: Andreas Mohr Cc: linux-rockchip@lists.infradead.org Cc: tony.xie@rock-chips.com Cc: John Stultz Cc: djkurtz@chromium.org Cc: linux@roeck-us.net Cc: tskd08@gmail.com Link: http://lkml.kernel.org/r/1477065531-30342-1-git-send-email-dianders@chromium.org Signed-off-by: Thomas Gleixner --- kernel/time/timer.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) (limited to 'kernel/time/timer.c') diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 2d47980a1bc4..12681c9a7683 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1896,16 +1896,6 @@ unsigned long msleep_interruptible(unsigned int msecs) EXPORT_SYMBOL(msleep_interruptible); -static void __sched do_usleep_range(unsigned long min, unsigned long max) -{ - ktime_t kmin; - u64 delta; - - kmin = ktime_set(0, min * NSEC_PER_USEC); - delta = (u64)(max - min) * NSEC_PER_USEC; - schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL); -} - /** * usleep_range - Sleep for an approximate time * @min: Minimum time in usecs to sleep @@ -1919,7 +1909,14 @@ static void __sched do_usleep_range(unsigned long min, unsigned long max) */ void __sched usleep_range(unsigned long min, unsigned long max) { - __set_current_state(TASK_UNINTERRUPTIBLE); - do_usleep_range(min, max); + ktime_t exp = ktime_add_us(ktime_get(), min); + u64 delta = (u64)(max - min) * NSEC_PER_USEC; + + for (;;) { + __set_current_state(TASK_UNINTERRUPTIBLE); + /* Do not return before the requested sleep time has elapsed */ + if (!schedule_hrtimeout_range(&exp, delta, HRTIMER_MODE_ABS)) + break; + } } EXPORT_SYMBOL(usleep_range); -- cgit v1.2.3 From 4b7e9cf9c84b09adc428e0433cd376b91f9c52a7 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Fri, 21 Oct 2016 08:58:51 -0700 Subject: timers: Fix documentation for schedule_timeout() and similar The documentation for schedule_timeout(), schedule_hrtimeout(), and schedule_hrtimeout_range() all claim that the routines couldn't possibly return early if the task state was TASK_UNINTERRUPTIBLE. This is simply not true since wake_up_process() will cause those routines to exit early. We cannot make schedule_[hr]timeout() loop until the timeout expires if the task state is uninterruptible because we have users which rely on the existing and designed behaviour. Make the documentation match the (correct) implementation. schedule_hrtimeout() returns -EINTR even when a uninterruptible task was woken up. This might look strange, but making the return code depend on the state is too much of an effort as it would affect all the call sites. There is no value in doing so, but we spell it out clearly in the documentation. Suggested-by: Daniel Kurtz Signed-off-by: Douglas Anderson Cc: huangtao@rock-chips.com Cc: heiko@sntech.de Cc: broonie@kernel.org Cc: briannorris@chromium.org Cc: Andreas Mohr Cc: linux-rockchip@lists.infradead.org Cc: tony.xie@rock-chips.com Cc: John Stultz Cc: linux@roeck-us.net Cc: tskd08@gmail.com Link: http://lkml.kernel.org/r/1477065531-30342-2-git-send-email-dianders@chromium.org Signed-off-by: Thomas Gleixner --- kernel/time/hrtimer.c | 20 ++++++++++++++------ kernel/time/timer.c | 11 +++++++---- 2 files changed, 21 insertions(+), 10 deletions(-) (limited to 'kernel/time/timer.c') diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index bb5ec425dfe0..08be5c99d26b 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1742,15 +1742,19 @@ schedule_hrtimeout_range_clock(ktime_t *expires, u64 delta, * You can set the task state as follows - * * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to - * pass before the routine returns. + * pass before the routine returns unless the current task is explicitly + * woken up, (e.g. by wake_up_process()). * * %TASK_INTERRUPTIBLE - the routine may return early if a signal is - * delivered to the current task. + * delivered to the current task or the current task is explicitly woken + * up. * * The current task state is guaranteed to be TASK_RUNNING when this * routine returns. * - * Returns 0 when the timer has expired otherwise -EINTR + * Returns 0 when the timer has expired. If the task was woken before the + * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or + * by an explicit wakeup, it returns -EINTR. */ int __sched schedule_hrtimeout_range(ktime_t *expires, u64 delta, const enum hrtimer_mode mode) @@ -1772,15 +1776,19 @@ EXPORT_SYMBOL_GPL(schedule_hrtimeout_range); * You can set the task state as follows - * * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to - * pass before the routine returns. + * pass before the routine returns unless the current task is explicitly + * woken up, (e.g. by wake_up_process()). * * %TASK_INTERRUPTIBLE - the routine may return early if a signal is - * delivered to the current task. + * delivered to the current task or the current task is explicitly woken + * up. * * The current task state is guaranteed to be TASK_RUNNING when this * routine returns. * - * Returns 0 when the timer has expired otherwise -EINTR + * Returns 0 when the timer has expired. If the task was woken before the + * timer expired by a signal (only possible in state TASK_INTERRUPTIBLE) or + * by an explicit wakeup, it returns -EINTR. */ int __sched schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode) diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 12681c9a7683..88aab86a4594 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1691,11 +1691,12 @@ static void process_timeout(unsigned long __data) * You can set the task state as follows - * * %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to - * pass before the routine returns. The routine will return 0 + * pass before the routine returns unless the current task is explicitly + * woken up, (e.g. by wake_up_process())". * * %TASK_INTERRUPTIBLE - the routine may return early if a signal is - * delivered to the current task. In this case the remaining time - * in jiffies will be returned, or 0 if the timer expired in time + * delivered to the current task or the current task is explicitly woken + * up. * * The current task state is guaranteed to be TASK_RUNNING when this * routine returns. @@ -1704,7 +1705,9 @@ static void process_timeout(unsigned long __data) * the CPU away without a bound on the timeout. In this case the return * value will be %MAX_SCHEDULE_TIMEOUT. * - * In all cases the return value is guaranteed to be non-negative. + * Returns 0 when the timer has expired otherwise the remaining time in + * jiffies will be returned. In all cases the return value is guaranteed + * to be non-negative. */ signed long __sched schedule_timeout(signed long timeout) { -- cgit v1.2.3 From 74ba181e61c6accf9066d6980f44588de2f854f6 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Fri, 11 Nov 2016 00:10:08 -0500 Subject: timer: Move sys_alarm from timer.c to itimer.c Move the only user of alarm_setitimer to itimer.c where it is defined. This allows for making alarm_setitimer static, and dropping it from the build when __ARCH_WANT_SYS_ALARM is not defined. Signed-off-by: Nicolas Pitre Acked-by: John Stultz Cc: Paul Bolle Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Richard Cochran Cc: Josh Triplett Cc: Michal Marek Cc: Edward Cree Link: http://lkml.kernel.org/r/1478841010-28605-5-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner --- include/linux/time.h | 2 -- kernel/time/itimer.c | 15 ++++++++++++++- kernel/time/timer.c | 13 ------------- 3 files changed, 14 insertions(+), 16 deletions(-) (limited to 'kernel/time/timer.c') diff --git a/include/linux/time.h b/include/linux/time.h index 4cea09d94208..23f0f5ce3090 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -172,8 +172,6 @@ extern int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue); extern int do_getitimer(int which, struct itimerval *value); -extern unsigned int alarm_setitimer(unsigned int seconds); - extern long do_utimes(int dfd, const char __user *filename, struct timespec *times, int flags); struct tms; diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c index 1d5c7204ddc9..2b9f45bc955d 100644 --- a/kernel/time/itimer.c +++ b/kernel/time/itimer.c @@ -238,6 +238,8 @@ again: return 0; } +#ifdef __ARCH_WANT_SYS_ALARM + /** * alarm_setitimer - set alarm in seconds * @@ -250,7 +252,7 @@ again: * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid * negative timeval settings which would cause immediate expiry. */ -unsigned int alarm_setitimer(unsigned int seconds) +static unsigned int alarm_setitimer(unsigned int seconds) { struct itimerval it_new, it_old; @@ -275,6 +277,17 @@ unsigned int alarm_setitimer(unsigned int seconds) 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) { diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 88aab86a4594..42d27aa242b9 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1662,19 +1662,6 @@ void run_local_timers(void) raise_softirq(TIMER_SOFTIRQ); } -#ifdef __ARCH_WANT_SYS_ALARM - -/* - * 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 void process_timeout(unsigned long __data) { wake_up_process((struct task_struct *)__data); -- cgit v1.2.3 From baa73d9e478ff32d62f3f9422822b59dd9a95a21 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Fri, 11 Nov 2016 00:10:10 -0500 Subject: posix-timers: Make them configurable Some embedded systems have no use for them. This removes about 25KB from the kernel binary size when configured out. Corresponding syscalls are routed to a stub logging the attempt to use those syscalls which should be enough of a clue if they were disabled without proper consideration. They are: timer_create, timer_gettime: timer_getoverrun, timer_settime, timer_delete, clock_adjtime, setitimer, getitimer, alarm. The clock_settime, clock_gettime, clock_getres and clock_nanosleep syscalls are replaced by simple wrappers compatible with CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only which should cover the vast majority of use cases with very little code. Signed-off-by: Nicolas Pitre Acked-by: Richard Cochran Acked-by: Thomas Gleixner Acked-by: John Stultz Reviewed-by: Josh Triplett Cc: Paul Bolle Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Michal Marek Cc: Edward Cree Link: http://lkml.kernel.org/r/1478841010-28605-7-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner --- arch/alpha/kernel/osf_sys.c | 8 +++ drivers/char/Kconfig | 1 + drivers/ptp/Kconfig | 2 +- fs/exec.c | 2 + init/Kconfig | 17 ++++++ kernel/compat.c | 8 +++ kernel/exit.c | 11 +++- kernel/fork.c | 2 + kernel/signal.c | 6 +++ kernel/sys.c | 3 +- kernel/time/Makefile | 10 +++- kernel/time/alarmtimer.c | 6 ++- kernel/time/posix-stubs.c | 123 ++++++++++++++++++++++++++++++++++++++++++++ kernel/time/timer.c | 3 +- security/selinux/hooks.c | 11 ++-- 15 files changed, 200 insertions(+), 13 deletions(-) create mode 100644 kernel/time/posix-stubs.c (limited to 'kernel/time/timer.c') diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c index ffb93f499c83..56e427c7aa3c 100644 --- a/arch/alpha/kernel/osf_sys.c +++ b/arch/alpha/kernel/osf_sys.c @@ -1029,11 +1029,16 @@ SYSCALL_DEFINE2(osf_settimeofday, struct timeval32 __user *, tv, return do_sys_settimeofday(tv ? &kts : NULL, tz ? &ktz : NULL); } +asmlinkage long sys_ni_posix_timers(void); + SYSCALL_DEFINE2(osf_getitimer, int, which, struct itimerval32 __user *, it) { struct itimerval kit; int error; + if (!IS_ENABLED(CONFIG_POSIX_TIMERS)) + return sys_ni_posix_timers(); + error = do_getitimer(which, &kit); if (!error && put_it32(it, &kit)) error = -EFAULT; @@ -1047,6 +1052,9 @@ SYSCALL_DEFINE3(osf_setitimer, int, which, struct itimerval32 __user *, in, struct itimerval kin, kout; int error; + if (!IS_ENABLED(CONFIG_POSIX_TIMERS)) + return sys_ni_posix_timers(); + if (in) { if (get_it32(&kin, in)) return -EFAULT; diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index dcc09739a54e..45ba878ae025 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -542,6 +542,7 @@ config HANGCHECK_TIMER config MMTIMER tristate "MMTIMER Memory mapped RTC for SGI Altix" depends on IA64_GENERIC || IA64_SGI_SN2 + depends on POSIX_TIMERS default y help The mmtimer device allows direct userspace access to the diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig index 0f7492f8ea23..bdce33291161 100644 --- a/drivers/ptp/Kconfig +++ b/drivers/ptp/Kconfig @@ -6,7 +6,7 @@ menu "PTP clock support" config PTP_1588_CLOCK tristate "PTP clock support" - depends on NET + depends on NET && POSIX_TIMERS select PPS select NET_PTP_CLASSIFY help diff --git a/fs/exec.c b/fs/exec.c index 4e497b9ee71e..923c57d96899 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1169,8 +1169,10 @@ no_thread_group: /* we have changed execution domain */ tsk->exit_signal = SIGCHLD; +#ifdef CONFIG_POSIX_TIMERS exit_itimers(sig); flush_itimer_signals(); +#endif if (atomic_read(&oldsighand->count) != 1) { struct sighand_struct *newsighand; diff --git a/init/Kconfig b/init/Kconfig index 34407f15e6d3..456e0b891238 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1445,6 +1445,23 @@ config SYSCTL_SYSCALL If unsure say N here. +config POSIX_TIMERS + bool "Posix Clocks & timers" if EXPERT + default y + help + This includes native support for POSIX timers to the kernel. + Some embedded systems have no use for them and therefore they + can be configured out to reduce the size of the kernel image. + + When this option is disabled, the following syscalls won't be + available: timer_create, timer_gettime: timer_getoverrun, + timer_settime, timer_delete, clock_adjtime, getitimer, + setitimer, alarm. Furthermore, the clock_settime, clock_gettime, + clock_getres and clock_nanosleep syscalls will be limited to + CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only. + + If unsure say y. + config KALLSYMS bool "Load all symbols for debugging/ksymoops" if EXPERT default y diff --git a/kernel/compat.c b/kernel/compat.c index 333d364be29d..b3a047f208a7 100644 --- a/kernel/compat.c +++ b/kernel/compat.c @@ -307,12 +307,17 @@ static inline long put_compat_itimerval(struct compat_itimerval __user *o, __put_user(i->it_value.tv_usec, &o->it_value.tv_usec))); } +asmlinkage long sys_ni_posix_timers(void); + COMPAT_SYSCALL_DEFINE2(getitimer, int, which, struct compat_itimerval __user *, it) { struct itimerval kit; int error; + if (!IS_ENABLED(CONFIG_POSIX_TIMERS)) + return sys_ni_posix_timers(); + error = do_getitimer(which, &kit); if (!error && put_compat_itimerval(it, &kit)) error = -EFAULT; @@ -326,6 +331,9 @@ COMPAT_SYSCALL_DEFINE3(setitimer, int, which, struct itimerval kin, kout; int error; + if (!IS_ENABLED(CONFIG_POSIX_TIMERS)) + return sys_ni_posix_timers(); + if (in) { if (get_compat_itimerval(&kin, in)) return -EFAULT; diff --git a/kernel/exit.c b/kernel/exit.c index d16bcdd89dbe..684de019b674 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -92,11 +92,10 @@ static void __exit_signal(struct task_struct *tsk) lockdep_tasklist_lock_is_held()); spin_lock(&sighand->siglock); +#ifdef CONFIG_POSIX_TIMERS posix_cpu_timers_exit(tsk); if (group_dead) { posix_cpu_timers_exit_group(tsk); - tty = sig->tty; - sig->tty = NULL; } else { /* * This can only happen if the caller is de_thread(). @@ -105,7 +104,13 @@ static void __exit_signal(struct task_struct *tsk) */ if (unlikely(has_group_leader_pid(tsk))) posix_cpu_timers_exit_group(tsk); + } +#endif + if (group_dead) { + tty = sig->tty; + sig->tty = NULL; + } else { /* * If there is any task waiting for the group exit * then notify it: @@ -803,8 +808,10 @@ void __noreturn do_exit(long code) acct_update_integrals(tsk); group_dead = atomic_dec_and_test(&tsk->signal->live); if (group_dead) { +#ifdef CONFIG_POSIX_TIMERS hrtimer_cancel(&tsk->signal->real_timer); exit_itimers(tsk->signal); +#endif if (tsk->mm) setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm); } diff --git a/kernel/fork.c b/kernel/fork.c index 623259fc794d..17da35fa77e7 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1342,8 +1342,10 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) seqlock_init(&sig->stats_lock); prev_cputime_init(&sig->prev_cputime); +#ifdef CONFIG_POSIX_TIMERS hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); sig->real_timer.function = it_real_fn; +#endif task_lock(current->group_leader); memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); diff --git a/kernel/signal.c b/kernel/signal.c index 75761acc77cf..29a410780aa9 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -427,6 +427,7 @@ void flush_signals(struct task_struct *t) spin_unlock_irqrestore(&t->sighand->siglock, flags); } +#ifdef CONFIG_POSIX_TIMERS static void __flush_itimer_signals(struct sigpending *pending) { sigset_t signal, retain; @@ -460,6 +461,7 @@ void flush_itimer_signals(void) __flush_itimer_signals(&tsk->signal->shared_pending); spin_unlock_irqrestore(&tsk->sighand->siglock, flags); } +#endif void ignore_signals(struct task_struct *t) { @@ -567,6 +569,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) if (!signr) { signr = __dequeue_signal(&tsk->signal->shared_pending, mask, info); +#ifdef CONFIG_POSIX_TIMERS /* * itimer signal ? * @@ -590,6 +593,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) hrtimer_restart(tmr); } } +#endif } recalc_sigpending(); @@ -611,6 +615,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) */ current->jobctl |= JOBCTL_STOP_DEQUEUED; } +#ifdef CONFIG_POSIX_TIMERS if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) { /* * Release the siglock to ensure proper locking order @@ -622,6 +627,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) do_schedule_next_timer(info); spin_lock(&tsk->sighand->siglock); } +#endif return signr; } diff --git a/kernel/sys.c b/kernel/sys.c index 89d5be418157..78c9fb7dd680 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1416,7 +1416,8 @@ int do_prlimit(struct task_struct *tsk, unsigned int resource, * applications, so we live with it */ if (!retval && new_rlim && resource == RLIMIT_CPU && - new_rlim->rlim_cur != RLIM_INFINITY) + new_rlim->rlim_cur != RLIM_INFINITY && + IS_ENABLED(CONFIG_POSIX_TIMERS)) update_rlimit_cpu(tsk, new_rlim->rlim_cur); out: read_unlock(&tasklist_lock); diff --git a/kernel/time/Makefile b/kernel/time/Makefile index 49eca0beed32..976840d29a71 100644 --- a/kernel/time/Makefile +++ b/kernel/time/Makefile @@ -1,6 +1,12 @@ -obj-y += time.o timer.o hrtimer.o itimer.o posix-timers.o posix-cpu-timers.o +obj-y += time.o timer.o hrtimer.o obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o -obj-y += timeconv.o timecounter.o posix-clock.o alarmtimer.o +obj-y += timeconv.o timecounter.o alarmtimer.o + +ifeq ($(CONFIG_POSIX_TIMERS),y) + obj-y += posix-timers.o posix-cpu-timers.o posix-clock.o itimer.o +else + obj-y += posix-stubs.o +endif obj-$(CONFIG_GENERIC_CLOCKEVENTS) += clockevents.o tick-common.o ifeq ($(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST),y) diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 12dd190634ab..a15caa3d1721 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -846,8 +846,10 @@ static int __init alarmtimer_init(void) alarmtimer_rtc_timer_init(); - posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock); - posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock); + if (IS_ENABLED(CONFIG_POSIX_TIMERS)) { + posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock); + posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock); + } /* Initialize alarm bases */ alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME; diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c new file mode 100644 index 000000000000..cd6716e115e8 --- /dev/null +++ b/kernel/time/posix-stubs.c @@ -0,0 +1,123 @@ +/* + * Dummy stubs used when CONFIG_POSIX_TIMERS=n + * + * Created by: Nicolas Pitre, July 2016 + * Copyright: (C) 2016 Linaro Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +asmlinkage long sys_ni_posix_timers(void) +{ + pr_err_once("process %d (%s) attempted a POSIX timer syscall " + "while CONFIG_POSIX_TIMERS is not set\n", + current->pid, current->comm); + return -ENOSYS; +} + +#define SYS_NI(name) SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers) + +SYS_NI(timer_create); +SYS_NI(timer_gettime); +SYS_NI(timer_getoverrun); +SYS_NI(timer_settime); +SYS_NI(timer_delete); +SYS_NI(clock_adjtime); +SYS_NI(getitimer); +SYS_NI(setitimer); +#ifdef __ARCH_WANT_SYS_ALARM +SYS_NI(alarm); +#endif + +/* + * We preserve minimal support for CLOCK_REALTIME and CLOCK_MONOTONIC + * as it is easy to remain compatible with little code. CLOCK_BOOTTIME + * is also included for convenience as at least systemd uses it. + */ + +SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock, + const struct timespec __user *, tp) +{ + struct timespec new_tp; + + if (which_clock != CLOCK_REALTIME) + return -EINVAL; + if (copy_from_user(&new_tp, tp, sizeof (*tp))) + return -EFAULT; + return do_sys_settimeofday(&new_tp, NULL); +} + +SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock, + struct timespec __user *,tp) +{ + struct timespec kernel_tp; + + switch (which_clock) { + case CLOCK_REALTIME: ktime_get_real_ts(&kernel_tp); break; + case CLOCK_MONOTONIC: ktime_get_ts(&kernel_tp); break; + case CLOCK_BOOTTIME: get_monotonic_boottime(&kernel_tp); break; + default: return -EINVAL; + } + if (copy_to_user(tp, &kernel_tp, sizeof (kernel_tp))) + return -EFAULT; + return 0; +} + +SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct timespec __user *, tp) +{ + struct timespec rtn_tp = { + .tv_sec = 0, + .tv_nsec = hrtimer_resolution, + }; + + switch (which_clock) { + case CLOCK_REALTIME: + case CLOCK_MONOTONIC: + case CLOCK_BOOTTIME: + if (copy_to_user(tp, &rtn_tp, sizeof(rtn_tp))) + return -EFAULT; + return 0; + default: + return -EINVAL; + } +} + +SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags, + const struct timespec __user *, rqtp, + struct timespec __user *, rmtp) +{ + struct timespec t; + + switch (which_clock) { + case CLOCK_REALTIME: + case CLOCK_MONOTONIC: + case CLOCK_BOOTTIME: + if (copy_from_user(&t, rqtp, sizeof (struct timespec))) + return -EFAULT; + if (!timespec_valid(&t)) + return -EINVAL; + return hrtimer_nanosleep(&t, rmtp, flags & TIMER_ABSTIME ? + HRTIMER_MODE_ABS : HRTIMER_MODE_REL, + which_clock); + default: + return -EINVAL; + } +} + +#ifdef CONFIG_COMPAT +long clock_nanosleep_restart(struct restart_block *restart_block) +{ + return hrtimer_nanosleep_restart(restart_block); +} +#endif diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 42d27aa242b9..e2892e454fe3 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1601,7 +1601,8 @@ void update_process_times(int user_tick) irq_work_tick(); #endif scheduler_tick(); - run_posix_cpu_timers(p); + if (IS_ENABLED(CONFIG_POSIX_TIMERS)) + run_posix_cpu_timers(p); } /** diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 09fd6108e421..38b79d797aaf 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2525,7 +2525,8 @@ static void selinux_bprm_committing_creds(struct linux_binprm *bprm) rlim->rlim_cur = min(rlim->rlim_max, initrlim->rlim_cur); } task_unlock(current); - update_rlimit_cpu(current, rlimit(RLIMIT_CPU)); + if (IS_ENABLED(CONFIG_POSIX_TIMERS)) + update_rlimit_cpu(current, rlimit(RLIMIT_CPU)); } } @@ -2555,9 +2556,11 @@ static void selinux_bprm_committed_creds(struct linux_binprm *bprm) */ rc = avc_has_perm(osid, sid, SECCLASS_PROCESS, PROCESS__SIGINH, NULL); if (rc) { - memset(&itimer, 0, sizeof itimer); - for (i = 0; i < 3; i++) - do_setitimer(i, &itimer, NULL); + if (IS_ENABLED(CONFIG_POSIX_TIMERS)) { + memset(&itimer, 0, sizeof itimer); + for (i = 0; i < 3; i++) + do_setitimer(i, &itimer, NULL); + } spin_lock_irq(¤t->sighand->siglock); if (!fatal_signal_pending(current)) { flush_sigqueue(¤t->pending); -- cgit v1.2.3