/* * linux/kernel/timer.c * * Kernel internal timers, kernel timekeeping, basic process system calls * * Copyright (C) 1991, 1992 Linus Torvalds * * 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better. * * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 * "A Kernel Model for Precision Timekeeping" by Dave Mills * 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to * serialize accesses to xtime/lost_ticks). * Copyright (C) 1998 Andrea Arcangeli * 1999-03-10 Improved NTP compatibility by Ulrich Windl * 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love * 2000-10-05 Implemented scalable SMP per-CPU timer handling. * Copyright (C) 2000, 2001, 2002 Ingo Molnar * Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar */ #include <linux/kernel_stat.h> #include <linux/interrupt.h> #include <linux/percpu.h> #include <linux/init.h> #include <linux/mm.h> #include <asm/uaccess.h> /* * per-CPU timer vector definitions: */ #define TVN_BITS 6 #define TVR_BITS 8 #define TVN_SIZE (1 << TVN_BITS) #define TVR_SIZE (1 << TVR_BITS) #define TVN_MASK (TVN_SIZE - 1) #define TVR_MASK (TVR_SIZE - 1) typedef struct tvec_s { int index; struct list_head vec[TVN_SIZE]; } tvec_t; typedef struct tvec_root_s { int index; struct list_head vec[TVR_SIZE]; } tvec_root_t; typedef struct timer_list timer_t; struct tvec_t_base_s { spinlock_t lock; unsigned long timer_jiffies; timer_t *running_timer; tvec_root_t tv1; tvec_t tv2; tvec_t tv3; tvec_t tv4; tvec_t tv5; } ____cacheline_aligned_in_smp; typedef struct tvec_t_base_s tvec_base_t; static tvec_base_t tvec_bases[NR_CPUS] __cacheline_aligned; /* Fake initialization needed to avoid compiler breakage */ static DEFINE_PER_CPU(struct tasklet_struct, timer_tasklet) = { NULL }; static inline void internal_add_timer(tvec_base_t *base, timer_t *timer) { unsigned long expires = timer->expires; unsigned long idx = expires - base->timer_jiffies; struct list_head *vec; if (idx < TVR_SIZE) { int i = expires & TVR_MASK; vec = base->tv1.vec + i; } else if (idx < 1 << (TVR_BITS + TVN_BITS)) { int i = (expires >> TVR_BITS) & TVN_MASK; vec = base->tv2.vec + i; } else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) { int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK; vec = base->tv3.vec + i; } else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) { int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK; vec = base->tv4.vec + i; } else if ((signed long) idx < 0) { /* * Can happen if you add a timer with expires == jiffies, * or you set a timer to go off in the past */ vec = base->tv1.vec + base->tv1.index; } else if (idx <= 0xffffffffUL) { int i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK; vec = base->tv5.vec + i; } else /* Can only get here on architectures with 64-bit jiffies */ return; /* * Timers are FIFO: */ list_add_tail(&timer->entry, vec); } /*** * add_timer - start a timer * @timer: the timer to be added * * The kernel will do a ->function(->data) callback from the * timer interrupt at the ->expired point in the future. The * current time is 'jiffies'. * * The timer's ->expired, ->function (and if the handler uses it, ->data) * fields must be set prior calling this function. * * Timers with an ->expired field in the past will be executed in the next * timer tick. It's illegal to add an already pending timer. */ void add_timer(timer_t *timer) { int cpu = get_cpu(); tvec_base_t *base = tvec_bases + cpu; unsigned long flags; BUG_ON(timer_pending(timer) || !timer->function); spin_lock_irqsave(&base->lock, flags); internal_add_timer(base, timer); timer->base = base; spin_unlock_irqrestore(&base->lock, flags); put_cpu(); } /*** * mod_timer - modify a timer's timeout * @timer: the timer to be modified * * mod_timer is a more efficient way to update the expire field of an * active timer (if the timer is inactive it will be activated) * * mod_timer(timer, expires) is equivalent to: * * del_timer(timer); timer->expires = expires; add_timer(timer); * * Note that if there are multiple unserialized concurrent users of the * same timer, then mod_timer() is the only safe way to modify the timeout, * since add_timer() cannot modify an already running timer. * * The function returns whether it has modified a pending timer or not. * (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an * active timer returns 1.) */ int mod_timer(timer_t *timer, unsigned long expires) { tvec_base_t *old_base, *new_base; unsigned long flags; int ret = 0; BUG_ON(!timer->function); /* * This is a common optimization triggered by the * networking code - if the timer is re-modified * to be the same thing then just return: */ if (timer->expires == expires && timer_pending(timer)) return 1; local_irq_save(flags); new_base = tvec_bases + smp_processor_id(); repeat: old_base = timer->base; /* * Prevent deadlocks via ordering by old_base < new_base. */ if (old_base && (new_base != old_base)) { if (old_base < new_base) { spin_lock(&new_base->lock); spin_lock(&old_base->lock); } else { spin_lock(&old_base->lock); spin_lock(&new_base->lock); } /* * The timer base might have changed while we were * trying to take the lock(s): */ if (timer->base != old_base) { spin_unlock(&new_base->lock); spin_unlock(&old_base->lock); goto repeat; } } else spin_lock(&new_base->lock); /* * Delete the previous timeout (if there was any), and install * the new one: */ if (old_base) { list_del(&timer->entry); ret = 1; } timer->expires = expires; internal_add_timer(new_base, timer); timer->base = new_base; if (old_base && (new_base != old_base)) spin_unlock(&old_base->lock); spin_unlock_irqrestore(&new_base->lock, flags); return ret; } /*** * del_timer - deactive a timer. * @timer: the timer to be deactivated * * del_timer() deactivates a timer - this works on both active and inactive * timers. * * The function returns whether it has deactivated a pending timer or not. * (ie. del_timer() of an inactive timer returns 0, del_timer() of an * active timer returns 1.) */ int del_timer(timer_t *timer) { unsigned long flags; tvec_base_t *base; repeat: base = timer->base; if (!base) return 0; spin_lock_irqsave(&base->lock, flags); if (base != timer->base) { spin_unlock_irqrestore(&base->lock, flags); goto repeat; } list_del(&timer->entry); timer->base = NULL; spin_unlock_irqrestore(&base->lock, flags); return 1; } #ifdef CONFIG_SMP /*** * del_timer_sync - deactivate a timer and wait for the handler to finish. * @timer: the timer to be deactivated * * This function only differs from del_timer() on SMP: besides deactivating * the timer it also makes sure the handler has finished executing on other * CPUs. * * Synchronization rules: callers must prevent restarting of the timer, * otherwise this function is meaningless. It must not be called from * interrupt contexts. Upon exit the timer is not queued and the handler * is not running on any CPU. * * The function returns whether it has deactivated a pending timer or not. */ int del_timer_sync(timer_t *timer) { tvec_base_t *base = tvec_bases; int i, ret; ret = del_timer(timer); for (i = 0; i < NR_CPUS; i++) { if (!cpu_online(i)) continue; if (base->running_timer == timer) { while (base->running_timer == timer) { cpu_relax(); preempt_disable(); preempt_enable(); } break; } base++; } return ret; } #endif static void cascade(tvec_base_t *base, tvec_t *tv) { /* cascade all the timers from tv up one level */ struct list_head *head, *curr, *next; head = tv->vec + tv->index; curr = head->next; /* * We are removing _all_ timers from the list, so we don't have to * detach them individually, just clear the list afterwards. */ while (curr != head) { timer_t *tmp; tmp = list_entry(curr, timer_t, entry); if (tmp->base != base) BUG(); next = curr->next; internal_add_timer(base, tmp); curr = next; } INIT_LIST_HEAD(head); tv->index = (tv->index + 1) & TVN_MASK; } /*** * __run_timers - run all expired timers (if any) on this CPU. * @base: the timer vector to be processed. * * This function cascades all vectors and executes all expired timer * vectors. */ static inline void __run_timers(tvec_base_t *base) { unsigned long flags; spin_lock_irqsave(&base->lock, flags); while ((long)(jiffies - base->timer_jiffies) >= 0) { struct list_head *head, *curr; /* * Cascade timers: */ if (!base->tv1.index) { cascade(base, &base->tv2); if (base->tv2.index == 1) { cascade(base, &base->tv3); if (base->tv3.index == 1) { cascade(base, &base->tv4); if (base->tv4.index == 1) cascade(base, &base->tv5); } } } repeat: head = base->tv1.vec + base->tv1.index; curr = head->next; if (curr != head) { void (*fn)(unsigned long); unsigned long data; timer_t *timer; timer = list_entry(curr, timer_t, entry); fn = timer->function; data = timer->data; list_del(&timer->entry); timer->base = NULL; #if CONFIG_SMP base->running_timer = timer; #endif spin_unlock_irq(&base->lock); fn(data); spin_lock_irq(&base->lock); goto repeat; } ++base->timer_jiffies; base->tv1.index = (base->tv1.index + 1) & TVR_MASK; } #if CONFIG_SMP base->running_timer = NULL; #endif spin_unlock_irqrestore(&base->lock, flags); } /******************************************************************/ /* * Timekeeping variables */ unsigned long tick_usec = TICK_USEC; /* ACTHZ period (usec) */ unsigned long tick_nsec = TICK_NSEC(TICK_USEC); /* USER_HZ period (nsec) */ /* The current time */ struct timespec xtime __attribute__ ((aligned (16))); /* Don't completely fail for HZ > 500. */ int tickadj = 500/HZ ? : 1; /* microsecs */ struct kernel_stat kstat; /* * phase-lock loop variables */ /* TIME_ERROR prevents overwriting the CMOS clock */ int time_state = TIME_OK; /* clock synchronization status */ int time_status = STA_UNSYNC; /* clock status bits */ long time_offset; /* time adjustment (us) */ long time_constant = 2; /* pll time constant */ long time_tolerance = MAXFREQ; /* frequency tolerance (ppm) */ long time_precision = 1; /* clock precision (us) */ long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */ long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */ long time_phase; /* phase offset (scaled us) */ long time_freq = ((1000000 + HZ/2) % HZ - HZ/2) << SHIFT_USEC; /* frequency offset (scaled ppm)*/ long time_adj; /* tick adjust (scaled 1 / HZ) */ long time_reftime; /* time at last adjustment (s) */ long time_adjust; unsigned int * prof_buffer; unsigned long prof_len; unsigned long prof_shift; /* * this routine handles the overflow of the microsecond field * * The tricky bits of code to handle the accurate clock support * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame. * They were originally developed for SUN and DEC kernels. * All the kudos should go to Dave for this stuff. * */ static void second_overflow(void) { long ltemp; /* Bump the maxerror field */ time_maxerror += time_tolerance >> SHIFT_USEC; if ( time_maxerror > NTP_PHASE_LIMIT ) { time_maxerror = NTP_PHASE_LIMIT; time_status |= STA_UNSYNC; } /* * Leap second processing. If in leap-insert state at * the end of the day, the system clock is set back one * second; if in leap-delete state, the system clock is * set ahead one second. The microtime() routine or * external clock driver will insure that reported time * is always monotonic. The ugly divides should be * replaced. */ switch (time_state) { case TIME_OK: if (time_status & STA_INS) time_state = TIME_INS; else if (time_status & STA_DEL) time_state = TIME_DEL; break; case TIME_INS: if (xtime.tv_sec % 86400 == 0) { xtime.tv_sec--; time_state = TIME_OOP; printk(KERN_NOTICE "Clock: inserting leap second 23:59:60 UTC\n"); } break; case TIME_DEL: if ((xtime.tv_sec + 1) % 86400 == 0) { xtime.tv_sec++; time_state = TIME_WAIT; printk(KERN_NOTICE "Clock: deleting leap second 23:59:59 UTC\n"); } break; case TIME_OOP: time_state = TIME_WAIT; break; case TIME_WAIT: if (!(time_status & (STA_INS | STA_DEL))) time_state = TIME_OK; } /* * Compute the phase adjustment for the next second. In * PLL mode, the offset is reduced by a fixed factor * times the time constant. In FLL mode the offset is * used directly. In either mode, the maximum phase * adjustment for each second is clamped so as to spread * the adjustment over not more than the number of * seconds between updates. */ if (time_offset < 0) { ltemp = -time_offset; if (!(time_status & STA_FLL)) ltemp >>= SHIFT_KG + time_constant; if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE; time_offset += ltemp; time_adj = -ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE); } else { ltemp = time_offset; if (!(time_status & STA_FLL)) ltemp >>= SHIFT_KG + time_constant; if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE) ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE; time_offset -= ltemp; time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE); } /* * Compute the frequency estimate and additional phase * adjustment due to frequency error for the next * second. When the PPS signal is engaged, gnaw on the * watchdog counter and update the frequency computed by * the pll and the PPS signal. */ pps_valid++; if (pps_valid == PPS_VALID) { /* PPS signal lost */ pps_jitter = MAXTIME; pps_stabil = MAXFREQ; time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR); } ltemp = time_freq + pps_freq; if (ltemp < 0) time_adj -= -ltemp >> (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE); else time_adj += ltemp >> (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE); #if HZ == 100 /* Compensate for (HZ==100) != (1 << SHIFT_HZ). * Add 25% and 3.125% to get 128.125; => only 0.125% error (p. 14) */ if (time_adj < 0) time_adj -= (-time_adj >> 2) + (-time_adj >> 5); else time_adj += (time_adj >> 2) + (time_adj >> 5); #endif } /* in the NTP reference this is called "hardclock()" */ static void update_wall_time_one_tick(void) { long time_adjust_step; if ( (time_adjust_step = time_adjust) != 0 ) { /* We are doing an adjtime thing. * * Prepare time_adjust_step to be within bounds. * Note that a positive time_adjust means we want the clock * to run faster. * * Limit the amount of the step to be in the range * -tickadj .. +tickadj */ if (time_adjust > tickadj) time_adjust_step = tickadj; else if (time_adjust < -tickadj) time_adjust_step = -tickadj; /* Reduce by this step the amount of time left */ time_adjust -= time_adjust_step; } xtime.tv_nsec += tick_nsec + time_adjust_step * 1000; /* * Advance the phase, once it gets to one microsecond, then * advance the tick more. */ time_phase += time_adj; if (time_phase <= -FINEUSEC) { long ltemp = -time_phase >> (SHIFT_SCALE - 10); time_phase += ltemp << (SHIFT_SCALE - 10); xtime.tv_nsec -= ltemp; } else if (time_phase >= FINEUSEC) { long ltemp = time_phase >> (SHIFT_SCALE - 10); time_phase -= ltemp << (SHIFT_SCALE - 10); xtime.tv_nsec += ltemp; } } /* * Using a loop looks inefficient, but "ticks" is * usually just one (we shouldn't be losing ticks, * we're doing this this way mainly for interrupt * latency reasons, not because we think we'll * have lots of lost timer ticks */ static void update_wall_time(unsigned long ticks) { do { ticks--; update_wall_time_one_tick(); } while (ticks); if (xtime.tv_nsec >= 1000000000) { xtime.tv_nsec -= 1000000000; xtime.tv_sec++; second_overflow(); } } static inline void do_process_times(struct task_struct *p, unsigned long user, unsigned long system) { unsigned long psecs; psecs = (p->utime += user); psecs += (p->stime += system); if (psecs / HZ > p->rlim[RLIMIT_CPU].rlim_cur) { /* Send SIGXCPU every second.. */ if (!(psecs % HZ)) send_sig(SIGXCPU, p, 1); /* and SIGKILL when we go over max.. */ if (psecs / HZ > p->rlim[RLIMIT_CPU].rlim_max) send_sig(SIGKILL, p, 1); } } static inline void do_it_virt(struct task_struct * p, unsigned long ticks) { unsigned long it_virt = p->it_virt_value; if (it_virt) { it_virt -= ticks; if (!it_virt) { it_virt = p->it_virt_incr; send_sig(SIGVTALRM, p, 1); } p->it_virt_value = it_virt; } } static inline void do_it_prof(struct task_struct *p) { unsigned long it_prof = p->it_prof_value; if (it_prof) { if (--it_prof == 0) { it_prof = p->it_prof_incr; send_sig(SIGPROF, p, 1); } p->it_prof_value = it_prof; } } void update_one_process(struct task_struct *p, unsigned long user, unsigned long system, int cpu) { p->per_cpu_utime[cpu] += user; p->per_cpu_stime[cpu] += system; do_process_times(p, user, system); do_it_virt(p, user); do_it_prof(p); } /* * Called from the timer interrupt handler to charge one tick to the current * process. user_tick is 1 if the tick is user time, 0 for system. */ void update_process_times(int user_tick) { struct task_struct *p = current; int cpu = smp_processor_id(), system = user_tick ^ 1; update_one_process(p, user_tick, system, cpu); run_local_timers(); scheduler_tick(user_tick, system); } /* * Nr of active tasks - counted in fixed-point numbers */ static unsigned long count_active_tasks(void) { return (nr_running() + nr_uninterruptible()) * FIXED_1; } /* * Hmm.. Changed this, as the GNU make sources (load.c) seems to * imply that avenrun[] is the standard name for this kind of thing. * Nothing else seems to be standardized: the fractional size etc * all seem to differ on different machines. * * Requires xtime_lock to access. */ unsigned long avenrun[3]; /* * calc_load - given tick count, update the avenrun load estimates. * This is called while holding a write_lock on xtime_lock. */ static inline void calc_load(unsigned long ticks) { unsigned long active_tasks; /* fixed-point */ static int count = LOAD_FREQ; count -= ticks; if (count < 0) { count += LOAD_FREQ; active_tasks = count_active_tasks(); CALC_LOAD(avenrun[0], EXP_1, active_tasks); CALC_LOAD(avenrun[1], EXP_5, active_tasks); CALC_LOAD(avenrun[2], EXP_15, active_tasks); } } /* jiffies at the most recent update of wall time */ unsigned long wall_jiffies; /* * This read-write spinlock protects us from races in SMP while * playing with xtime and avenrun. */ rwlock_t xtime_lock __cacheline_aligned_in_smp = RW_LOCK_UNLOCKED; unsigned long last_time_offset; /* * This function runs timers and the timer-tq in softirq context. */ static void run_timer_tasklet(unsigned long data) { tvec_base_t *base = tvec_bases + smp_processor_id(); if ((long)(jiffies - base->timer_jiffies) >= 0) __run_timers(base); } /* * Called by the local, per-CPU timer interrupt on SMP. */ void run_local_timers(void) { tasklet_hi_schedule(&per_cpu(timer_tasklet, smp_processor_id())); } /* * Called by the timer interrupt. xtime_lock must already be taken * by the timer IRQ! */ static inline void update_times(void) { unsigned long ticks; ticks = jiffies - wall_jiffies; if (ticks) { wall_jiffies += ticks; update_wall_time(ticks); } last_time_offset = 0; calc_load(ticks); } /* * The 64-bit jiffies value is not atomic - you MUST NOT read it * without holding read_lock_irq(&xtime_lock). * jiffies is defined in the linker script... */ void do_timer(struct pt_regs *regs) { jiffies_64++; #ifndef CONFIG_SMP /* SMP process accounting uses the local APIC timer */ update_process_times(user_mode(regs)); #endif update_times(); } #if !defined(__alpha__) && !defined(__ia64__) extern int do_setitimer(int, struct itimerval *, struct itimerval *); /* * For backwards compatibility? This can be done in libc so Alpha * and all newer ports shouldn't need it. */ asmlinkage unsigned long sys_alarm(unsigned int seconds) { struct itimerval it_new, it_old; unsigned int oldalarm; it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0; it_new.it_value.tv_sec = seconds; it_new.it_value.tv_usec = 0; do_setitimer(ITIMER_REAL, &it_new, &it_old); oldalarm = it_old.it_value.tv_sec; /* ehhh.. 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_usec) oldalarm++; return oldalarm; } #endif #ifndef __alpha__ /* * The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this * should be moved into arch/i386 instead? */ asmlinkage long sys_getpid(void) { /* This is SMP safe - current->pid doesn't change */ return current->tgid; } /* * This is not strictly SMP safe: p_opptr could change * from under us. However, rather than getting any lock * we can use an optimistic algorithm: get the parent * pid, and go back and check that the parent is still * the same. If it has changed (which is extremely unlikely * indeed), we just try again.. * * NOTE! This depends on the fact that even if we _do_ * get an old value of "parent", we can happily dereference * the pointer: we just can't necessarily trust the result * until we know that the parent pointer is valid. * * The "mb()" macro is a memory barrier - a synchronizing * event. It also makes sure that gcc doesn't optimize * away the necessary memory references.. The barrier doesn't * have to have all that strong semantics: on x86 we don't * really require a synchronizing instruction, for example. * The barrier is more important for code generation than * for any real memory ordering semantics (even if there is * a small window for a race, using the old pointer is * harmless for a while). */ asmlinkage long sys_getppid(void) { int pid; struct task_struct * me = current; struct task_struct * parent; parent = me->real_parent; for (;;) { pid = parent->pid; #if CONFIG_SMP { struct task_struct *old = parent; mb(); parent = me->real_parent; if (old != parent) continue; } #endif break; } return pid; } asmlinkage long sys_getuid(void) { /* Only we change this so SMP safe */ return current->uid; } asmlinkage long sys_geteuid(void) { /* Only we change this so SMP safe */ return current->euid; } asmlinkage long sys_getgid(void) { /* Only we change this so SMP safe */ return current->gid; } asmlinkage long sys_getegid(void) { /* Only we change this so SMP safe */ return current->egid; } #endif static void process_timeout(unsigned long __data) { wake_up_process((task_t *)__data); } /** * schedule_timeout - sleep until timeout * @timeout: timeout value in jiffies * * Make the current task sleep until @timeout jiffies have * elapsed. The routine will return immediately unless * the current task state has been set (see set_current_state()). * * 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 * * %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 * * The current task state is guaranteed to be TASK_RUNNING when this * routine returns. * * Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule * 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. */ signed long schedule_timeout(signed long timeout) { timer_t timer; unsigned long expire; switch (timeout) { case MAX_SCHEDULE_TIMEOUT: /* * These two special cases are useful to be comfortable * in the caller. Nothing more. We could take * MAX_SCHEDULE_TIMEOUT from one of the negative value * but I' d like to return a valid offset (>=0) to allow * the caller to do everything it want with the retval. */ schedule(); goto out; default: /* * Another bit of PARANOID. Note that the retval will be * 0 since no piece of kernel is supposed to do a check * for a negative retval of schedule_timeout() (since it * should never happens anyway). You just have the printk() * that will tell you if something is gone wrong and where. */ if (timeout < 0) { printk(KERN_ERR "schedule_timeout: wrong timeout " "value %lx from %p\n", timeout, __builtin_return_address(0)); current->state = TASK_RUNNING; goto out; } } expire = timeout + jiffies; init_timer(&timer); timer.expires = expire; timer.data = (unsigned long) current; timer.function = process_timeout; add_timer(&timer); schedule(); del_timer_sync(&timer); timeout = expire - jiffies; out: return timeout < 0 ? 0 : timeout; } /* Thread ID - the internal kernel "pid" */ asmlinkage long sys_gettid(void) { return current->pid; } asmlinkage long sys_nanosleep(struct timespec *rqtp, struct timespec *rmtp) { struct timespec t; unsigned long expire; if(copy_from_user(&t, rqtp, sizeof(struct timespec))) return -EFAULT; if (t.tv_nsec >= 1000000000L || t.tv_nsec < 0 || t.tv_sec < 0) return -EINVAL; expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec); current->state = TASK_INTERRUPTIBLE; expire = schedule_timeout(expire); if (expire) { if (rmtp) { jiffies_to_timespec(expire, &t); if (copy_to_user(rmtp, &t, sizeof(struct timespec))) return -EFAULT; } return -EINTR; } return 0; } /* * sys_sysinfo - fill in sysinfo struct */ asmlinkage long sys_sysinfo(struct sysinfo *info) { struct sysinfo val; unsigned long mem_total, sav_total; unsigned int mem_unit, bitcount; memset((char *)&val, 0, sizeof(struct sysinfo)); read_lock_irq(&xtime_lock); val.uptime = jiffies / HZ; val.loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT); val.loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT); val.loads[2] = avenrun[2] << (SI_LOAD_SHIFT - FSHIFT); val.procs = nr_threads; read_unlock_irq(&xtime_lock); si_meminfo(&val); si_swapinfo(&val); /* * If the sum of all the available memory (i.e. ram + swap) * is less than can be stored in a 32 bit unsigned long then * we can be binary compatible with 2.2.x kernels. If not, * well, in that case 2.2.x was broken anyways... * * -Erik Andersen <andersee@debian.org> */ mem_total = val.totalram + val.totalswap; if (mem_total < val.totalram || mem_total < val.totalswap) goto out; bitcount = 0; mem_unit = val.mem_unit; while (mem_unit > 1) { bitcount++; mem_unit >>= 1; sav_total = mem_total; mem_total <<= 1; if (mem_total < sav_total) goto out; } /* * If mem_total did not overflow, multiply all memory values by * val.mem_unit and set it to 1. This leaves things compatible * with 2.2.x, and also retains compatibility with earlier 2.4.x * kernels... */ val.mem_unit = 1; val.totalram <<= bitcount; val.freeram <<= bitcount; val.sharedram <<= bitcount; val.bufferram <<= bitcount; val.totalswap <<= bitcount; val.freeswap <<= bitcount; val.totalhigh <<= bitcount; val.freehigh <<= bitcount; out: if (copy_to_user(info, &val, sizeof(struct sysinfo))) return -EFAULT; return 0; } void __init init_timers(void) { int i, j; for (i = 0; i < NR_CPUS; i++) { tvec_base_t *base; base = tvec_bases + i; spin_lock_init(&base->lock); for (j = 0; j < TVN_SIZE; j++) { INIT_LIST_HEAD(base->tv5.vec + j); INIT_LIST_HEAD(base->tv4.vec + j); INIT_LIST_HEAD(base->tv3.vec + j); INIT_LIST_HEAD(base->tv2.vec + j); } for (j = 0; j < TVR_SIZE; j++) INIT_LIST_HEAD(base->tv1.vec + j); tasklet_init(&per_cpu(timer_tasklet, i), run_timer_tasklet, 0); } }