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![David Meybohm](/assets/img/avatar_default.png)
With CONFIG_PREEMPT && !CONFIG_SMP, it's possible for sys_getppid to return a bogus value if the parent's task_struct gets reallocated after current->group_leader->real_parent is read: asmlinkage long sys_getppid(void) { int pid; struct task_struct *me = current; struct task_struct *parent; parent = me->group_leader->real_parent; RACE HERE => for (;;) { pid = parent->tgid; #ifdef CONFIG_SMP { struct task_struct *old = parent; /* * Make sure we read the pid before re-reading the * parent pointer: */ smp_rmb(); parent = me->group_leader->real_parent; if (old != parent) continue; } #endif break; } return pid; } If the process gets preempted at the indicated point, the parent process can go ahead and call exit() and then get wait()'d on to reap its task_struct. When the preempted process gets resumed, it will not do any further checks of the parent pointer on !CONFIG_SMP: it will read the bad pid and return. So, the same algorithm used when SMP is enabled should be used when preempt is enabled, which will recheck ->real_parent in this case. Signed-off-by: David Meybohm <dmeybohmlkml@bellsouth.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1614 lines
42 KiB
C
1614 lines
42 KiB
C
/*
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* linux/kernel/timer.c
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*
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* Kernel internal timers, kernel timekeeping, basic process system calls
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* 1997-01-28 Modified by Finn Arne Gangstad to make timers scale better.
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*
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* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
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* "A Kernel Model for Precision Timekeeping" by Dave Mills
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* 1998-12-24 Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
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* serialize accesses to xtime/lost_ticks).
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* Copyright (C) 1998 Andrea Arcangeli
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* 1999-03-10 Improved NTP compatibility by Ulrich Windl
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* 2002-05-31 Move sys_sysinfo here and make its locking sane, Robert Love
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* 2000-10-05 Implemented scalable SMP per-CPU timer handling.
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* Copyright (C) 2000, 2001, 2002 Ingo Molnar
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* Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar
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*/
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#include <linux/kernel_stat.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/percpu.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/notifier.h>
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#include <linux/thread_info.h>
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#include <linux/time.h>
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#include <linux/jiffies.h>
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#include <linux/posix-timers.h>
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#include <linux/cpu.h>
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#include <linux/syscalls.h>
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#include <asm/uaccess.h>
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#include <asm/unistd.h>
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#include <asm/div64.h>
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#include <asm/timex.h>
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#include <asm/io.h>
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#ifdef CONFIG_TIME_INTERPOLATION
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static void time_interpolator_update(long delta_nsec);
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#else
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#define time_interpolator_update(x)
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#endif
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/*
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* per-CPU timer vector definitions:
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*/
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#define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
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#define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
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#define TVN_SIZE (1 << TVN_BITS)
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#define TVR_SIZE (1 << TVR_BITS)
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#define TVN_MASK (TVN_SIZE - 1)
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#define TVR_MASK (TVR_SIZE - 1)
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struct timer_base_s {
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spinlock_t lock;
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struct timer_list *running_timer;
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};
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typedef struct tvec_s {
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struct list_head vec[TVN_SIZE];
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} tvec_t;
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typedef struct tvec_root_s {
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struct list_head vec[TVR_SIZE];
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} tvec_root_t;
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struct tvec_t_base_s {
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struct timer_base_s t_base;
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unsigned long timer_jiffies;
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tvec_root_t tv1;
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tvec_t tv2;
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tvec_t tv3;
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tvec_t tv4;
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tvec_t tv5;
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} ____cacheline_aligned_in_smp;
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typedef struct tvec_t_base_s tvec_base_t;
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static DEFINE_PER_CPU(tvec_base_t, tvec_bases);
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static inline void set_running_timer(tvec_base_t *base,
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struct timer_list *timer)
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{
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#ifdef CONFIG_SMP
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base->t_base.running_timer = timer;
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#endif
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}
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static void check_timer_failed(struct timer_list *timer)
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{
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static int whine_count;
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if (whine_count < 16) {
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whine_count++;
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printk("Uninitialised timer!\n");
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printk("This is just a warning. Your computer is OK\n");
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printk("function=0x%p, data=0x%lx\n",
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timer->function, timer->data);
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dump_stack();
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}
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/*
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* Now fix it up
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*/
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timer->magic = TIMER_MAGIC;
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}
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static inline void check_timer(struct timer_list *timer)
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{
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if (timer->magic != TIMER_MAGIC)
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check_timer_failed(timer);
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}
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static void internal_add_timer(tvec_base_t *base, struct timer_list *timer)
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{
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unsigned long expires = timer->expires;
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unsigned long idx = expires - base->timer_jiffies;
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struct list_head *vec;
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if (idx < TVR_SIZE) {
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int i = expires & TVR_MASK;
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vec = base->tv1.vec + i;
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} else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
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int i = (expires >> TVR_BITS) & TVN_MASK;
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vec = base->tv2.vec + i;
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} else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
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int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
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vec = base->tv3.vec + i;
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} else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
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int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
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vec = base->tv4.vec + i;
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} else if ((signed long) idx < 0) {
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/*
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* Can happen if you add a timer with expires == jiffies,
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* or you set a timer to go off in the past
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*/
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vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK);
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} else {
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int i;
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/* If the timeout is larger than 0xffffffff on 64-bit
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* architectures then we use the maximum timeout:
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*/
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if (idx > 0xffffffffUL) {
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idx = 0xffffffffUL;
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expires = idx + base->timer_jiffies;
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}
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i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
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vec = base->tv5.vec + i;
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}
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/*
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* Timers are FIFO:
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*/
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list_add_tail(&timer->entry, vec);
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}
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typedef struct timer_base_s timer_base_t;
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/*
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* Used by TIMER_INITIALIZER, we can't use per_cpu(tvec_bases)
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* at compile time, and we need timer->base to lock the timer.
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*/
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timer_base_t __init_timer_base
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____cacheline_aligned_in_smp = { .lock = SPIN_LOCK_UNLOCKED };
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EXPORT_SYMBOL(__init_timer_base);
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/***
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* init_timer - initialize a timer.
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* @timer: the timer to be initialized
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*
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* init_timer() must be done to a timer prior calling *any* of the
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* other timer functions.
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*/
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void fastcall init_timer(struct timer_list *timer)
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{
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timer->entry.next = NULL;
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timer->base = &per_cpu(tvec_bases, raw_smp_processor_id()).t_base;
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timer->magic = TIMER_MAGIC;
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}
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EXPORT_SYMBOL(init_timer);
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static inline void detach_timer(struct timer_list *timer,
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int clear_pending)
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{
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struct list_head *entry = &timer->entry;
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__list_del(entry->prev, entry->next);
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if (clear_pending)
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entry->next = NULL;
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entry->prev = LIST_POISON2;
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}
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/*
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* We are using hashed locking: holding per_cpu(tvec_bases).t_base.lock
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* means that all timers which are tied to this base via timer->base are
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* locked, and the base itself is locked too.
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*
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* So __run_timers/migrate_timers can safely modify all timers which could
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* be found on ->tvX lists.
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*
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* When the timer's base is locked, and the timer removed from list, it is
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* possible to set timer->base = NULL and drop the lock: the timer remains
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* locked.
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*/
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static timer_base_t *lock_timer_base(struct timer_list *timer,
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unsigned long *flags)
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{
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timer_base_t *base;
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for (;;) {
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base = timer->base;
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if (likely(base != NULL)) {
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spin_lock_irqsave(&base->lock, *flags);
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if (likely(base == timer->base))
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return base;
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/* The timer has migrated to another CPU */
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spin_unlock_irqrestore(&base->lock, *flags);
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}
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cpu_relax();
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}
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}
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int __mod_timer(struct timer_list *timer, unsigned long expires)
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{
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timer_base_t *base;
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tvec_base_t *new_base;
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unsigned long flags;
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int ret = 0;
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BUG_ON(!timer->function);
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check_timer(timer);
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base = lock_timer_base(timer, &flags);
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if (timer_pending(timer)) {
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detach_timer(timer, 0);
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ret = 1;
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}
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new_base = &__get_cpu_var(tvec_bases);
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if (base != &new_base->t_base) {
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/*
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* We are trying to schedule the timer on the local CPU.
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* However we can't change timer's base while it is running,
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* otherwise del_timer_sync() can't detect that the timer's
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* handler yet has not finished. This also guarantees that
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* the timer is serialized wrt itself.
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*/
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if (unlikely(base->running_timer == timer)) {
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/* The timer remains on a former base */
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new_base = container_of(base, tvec_base_t, t_base);
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} else {
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/* See the comment in lock_timer_base() */
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timer->base = NULL;
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spin_unlock(&base->lock);
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spin_lock(&new_base->t_base.lock);
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timer->base = &new_base->t_base;
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}
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}
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timer->expires = expires;
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internal_add_timer(new_base, timer);
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spin_unlock_irqrestore(&new_base->t_base.lock, flags);
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return ret;
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}
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EXPORT_SYMBOL(__mod_timer);
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/***
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* add_timer_on - start a timer on a particular CPU
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* @timer: the timer to be added
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* @cpu: the CPU to start it on
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*
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* This is not very scalable on SMP. Double adds are not possible.
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*/
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void add_timer_on(struct timer_list *timer, int cpu)
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{
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tvec_base_t *base = &per_cpu(tvec_bases, cpu);
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unsigned long flags;
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BUG_ON(timer_pending(timer) || !timer->function);
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check_timer(timer);
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spin_lock_irqsave(&base->t_base.lock, flags);
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timer->base = &base->t_base;
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internal_add_timer(base, timer);
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spin_unlock_irqrestore(&base->t_base.lock, flags);
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}
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/***
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* mod_timer - modify a timer's timeout
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* @timer: the timer to be modified
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*
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* mod_timer is a more efficient way to update the expire field of an
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* active timer (if the timer is inactive it will be activated)
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*
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* mod_timer(timer, expires) is equivalent to:
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*
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* del_timer(timer); timer->expires = expires; add_timer(timer);
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*
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* Note that if there are multiple unserialized concurrent users of the
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* same timer, then mod_timer() is the only safe way to modify the timeout,
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* since add_timer() cannot modify an already running timer.
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*
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* The function returns whether it has modified a pending timer or not.
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* (ie. mod_timer() of an inactive timer returns 0, mod_timer() of an
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* active timer returns 1.)
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*/
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int mod_timer(struct timer_list *timer, unsigned long expires)
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{
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BUG_ON(!timer->function);
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check_timer(timer);
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/*
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* This is a common optimization triggered by the
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* networking code - if the timer is re-modified
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* to be the same thing then just return:
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*/
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if (timer->expires == expires && timer_pending(timer))
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return 1;
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return __mod_timer(timer, expires);
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}
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EXPORT_SYMBOL(mod_timer);
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/***
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* del_timer - deactive a timer.
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* @timer: the timer to be deactivated
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*
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* del_timer() deactivates a timer - this works on both active and inactive
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* timers.
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*
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* The function returns whether it has deactivated a pending timer or not.
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* (ie. del_timer() of an inactive timer returns 0, del_timer() of an
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* active timer returns 1.)
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*/
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int del_timer(struct timer_list *timer)
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{
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timer_base_t *base;
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unsigned long flags;
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int ret = 0;
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check_timer(timer);
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if (timer_pending(timer)) {
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base = lock_timer_base(timer, &flags);
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if (timer_pending(timer)) {
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detach_timer(timer, 1);
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ret = 1;
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}
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spin_unlock_irqrestore(&base->lock, flags);
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}
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return ret;
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}
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EXPORT_SYMBOL(del_timer);
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#ifdef CONFIG_SMP
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/*
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* This function tries to deactivate a timer. Upon successful (ret >= 0)
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* exit the timer is not queued and the handler is not running on any CPU.
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*
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* It must not be called from interrupt contexts.
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*/
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int try_to_del_timer_sync(struct timer_list *timer)
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{
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timer_base_t *base;
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unsigned long flags;
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int ret = -1;
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base = lock_timer_base(timer, &flags);
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if (base->running_timer == timer)
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goto out;
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ret = 0;
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if (timer_pending(timer)) {
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detach_timer(timer, 1);
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ret = 1;
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}
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out:
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spin_unlock_irqrestore(&base->lock, flags);
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return ret;
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}
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/***
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* del_timer_sync - deactivate a timer and wait for the handler to finish.
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* @timer: the timer to be deactivated
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*
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* This function only differs from del_timer() on SMP: besides deactivating
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* the timer it also makes sure the handler has finished executing on other
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* CPUs.
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*
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* Synchronization rules: callers must prevent restarting of the timer,
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* otherwise this function is meaningless. It must not be called from
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* interrupt contexts. The caller must not hold locks which would prevent
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* completion of the timer's handler. The timer's handler must not call
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* add_timer_on(). Upon exit the timer is not queued and the handler is
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* not running on any CPU.
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*
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* The function returns whether it has deactivated a pending timer or not.
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*/
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int del_timer_sync(struct timer_list *timer)
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{
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check_timer(timer);
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for (;;) {
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int ret = try_to_del_timer_sync(timer);
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if (ret >= 0)
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return ret;
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}
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}
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EXPORT_SYMBOL(del_timer_sync);
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#endif
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|
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static int cascade(tvec_base_t *base, tvec_t *tv, int index)
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{
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/* cascade all the timers from tv up one level */
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struct list_head *head, *curr;
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head = tv->vec + index;
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curr = head->next;
|
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/*
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* We are removing _all_ timers from the list, so we don't have to
|
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* detach them individually, just clear the list afterwards.
|
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*/
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while (curr != head) {
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struct timer_list *tmp;
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|
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tmp = list_entry(curr, struct timer_list, entry);
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BUG_ON(tmp->base != &base->t_base);
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curr = curr->next;
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internal_add_timer(base, tmp);
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}
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INIT_LIST_HEAD(head);
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return index;
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}
|
|
|
|
/***
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* __run_timers - run all expired timers (if any) on this CPU.
|
|
* @base: the timer vector to be processed.
|
|
*
|
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* This function cascades all vectors and executes all expired timer
|
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* vectors.
|
|
*/
|
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#define INDEX(N) (base->timer_jiffies >> (TVR_BITS + N * TVN_BITS)) & TVN_MASK
|
|
|
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static inline void __run_timers(tvec_base_t *base)
|
|
{
|
|
struct timer_list *timer;
|
|
|
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spin_lock_irq(&base->t_base.lock);
|
|
while (time_after_eq(jiffies, base->timer_jiffies)) {
|
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struct list_head work_list = LIST_HEAD_INIT(work_list);
|
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struct list_head *head = &work_list;
|
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int index = base->timer_jiffies & TVR_MASK;
|
|
|
|
/*
|
|
* Cascade timers:
|
|
*/
|
|
if (!index &&
|
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(!cascade(base, &base->tv2, INDEX(0))) &&
|
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(!cascade(base, &base->tv3, INDEX(1))) &&
|
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!cascade(base, &base->tv4, INDEX(2)))
|
|
cascade(base, &base->tv5, INDEX(3));
|
|
++base->timer_jiffies;
|
|
list_splice_init(base->tv1.vec + index, &work_list);
|
|
while (!list_empty(head)) {
|
|
void (*fn)(unsigned long);
|
|
unsigned long data;
|
|
|
|
timer = list_entry(head->next,struct timer_list,entry);
|
|
fn = timer->function;
|
|
data = timer->data;
|
|
|
|
set_running_timer(base, timer);
|
|
detach_timer(timer, 1);
|
|
spin_unlock_irq(&base->t_base.lock);
|
|
{
|
|
int preempt_count = preempt_count();
|
|
fn(data);
|
|
if (preempt_count != preempt_count()) {
|
|
printk(KERN_WARNING "huh, entered %p "
|
|
"with preempt_count %08x, exited"
|
|
" with %08x?\n",
|
|
fn, preempt_count,
|
|
preempt_count());
|
|
BUG();
|
|
}
|
|
}
|
|
spin_lock_irq(&base->t_base.lock);
|
|
}
|
|
}
|
|
set_running_timer(base, NULL);
|
|
spin_unlock_irq(&base->t_base.lock);
|
|
}
|
|
|
|
#ifdef CONFIG_NO_IDLE_HZ
|
|
/*
|
|
* Find out when the next timer event is due to happen. This
|
|
* is used on S/390 to stop all activity when a cpus is idle.
|
|
* This functions needs to be called disabled.
|
|
*/
|
|
unsigned long next_timer_interrupt(void)
|
|
{
|
|
tvec_base_t *base;
|
|
struct list_head *list;
|
|
struct timer_list *nte;
|
|
unsigned long expires;
|
|
tvec_t *varray[4];
|
|
int i, j;
|
|
|
|
base = &__get_cpu_var(tvec_bases);
|
|
spin_lock(&base->t_base.lock);
|
|
expires = base->timer_jiffies + (LONG_MAX >> 1);
|
|
list = 0;
|
|
|
|
/* Look for timer events in tv1. */
|
|
j = base->timer_jiffies & TVR_MASK;
|
|
do {
|
|
list_for_each_entry(nte, base->tv1.vec + j, entry) {
|
|
expires = nte->expires;
|
|
if (j < (base->timer_jiffies & TVR_MASK))
|
|
list = base->tv2.vec + (INDEX(0));
|
|
goto found;
|
|
}
|
|
j = (j + 1) & TVR_MASK;
|
|
} while (j != (base->timer_jiffies & TVR_MASK));
|
|
|
|
/* Check tv2-tv5. */
|
|
varray[0] = &base->tv2;
|
|
varray[1] = &base->tv3;
|
|
varray[2] = &base->tv4;
|
|
varray[3] = &base->tv5;
|
|
for (i = 0; i < 4; i++) {
|
|
j = INDEX(i);
|
|
do {
|
|
if (list_empty(varray[i]->vec + j)) {
|
|
j = (j + 1) & TVN_MASK;
|
|
continue;
|
|
}
|
|
list_for_each_entry(nte, varray[i]->vec + j, entry)
|
|
if (time_before(nte->expires, expires))
|
|
expires = nte->expires;
|
|
if (j < (INDEX(i)) && i < 3)
|
|
list = varray[i + 1]->vec + (INDEX(i + 1));
|
|
goto found;
|
|
} while (j != (INDEX(i)));
|
|
}
|
|
found:
|
|
if (list) {
|
|
/*
|
|
* The search wrapped. We need to look at the next list
|
|
* from next tv element that would cascade into tv element
|
|
* where we found the timer element.
|
|
*/
|
|
list_for_each_entry(nte, list, entry) {
|
|
if (time_before(nte->expires, expires))
|
|
expires = nte->expires;
|
|
}
|
|
}
|
|
spin_unlock(&base->t_base.lock);
|
|
return expires;
|
|
}
|
|
#endif
|
|
|
|
/******************************************************************/
|
|
|
|
/*
|
|
* Timekeeping variables
|
|
*/
|
|
unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
|
|
unsigned long tick_nsec = TICK_NSEC; /* ACTHZ period (nsec) */
|
|
|
|
/*
|
|
* The current time
|
|
* wall_to_monotonic is what we need to add to xtime (or xtime corrected
|
|
* for sub jiffie times) to get to monotonic time. Monotonic is pegged
|
|
* at zero at system boot time, so wall_to_monotonic will be negative,
|
|
* however, we will ALWAYS keep the tv_nsec part positive so we can use
|
|
* the usual normalization.
|
|
*/
|
|
struct timespec xtime __attribute__ ((aligned (16)));
|
|
struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
|
|
|
|
EXPORT_SYMBOL(xtime);
|
|
|
|
/* Don't completely fail for HZ > 500. */
|
|
int tickadj = 500/HZ ? : 1; /* microsecs */
|
|
|
|
|
|
/*
|
|
* 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) */
|
|
static long time_phase; /* phase offset (scaled us) */
|
|
long time_freq = (((NSEC_PER_SEC + HZ/2) % HZ - HZ/2) << SHIFT_USEC) / NSEC_PER_USEC;
|
|
/* frequency offset (scaled ppm)*/
|
|
static long time_adj; /* tick adjust (scaled 1 / HZ) */
|
|
long time_reftime; /* time at last adjustment (s) */
|
|
long time_adjust;
|
|
long time_next_adjust;
|
|
|
|
/*
|
|
* 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--;
|
|
wall_to_monotonic.tv_sec++;
|
|
/* The timer interpolator will make time change gradually instead
|
|
* of an immediate jump by one second.
|
|
*/
|
|
time_interpolator_update(-NSEC_PER_SEC);
|
|
time_state = TIME_OOP;
|
|
clock_was_set();
|
|
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++;
|
|
wall_to_monotonic.tv_sec--;
|
|
/* Use of time interpolator for a gradual change of time */
|
|
time_interpolator_update(NSEC_PER_SEC);
|
|
time_state = TIME_WAIT;
|
|
clock_was_set();
|
|
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
|
|
#if HZ == 1000
|
|
/* Compensate for (HZ==1000) != (1 << SHIFT_HZ).
|
|
* Add 1.5625% and 0.78125% to get 1023.4375; => only 0.05% error (p. 14)
|
|
*/
|
|
if (time_adj < 0)
|
|
time_adj -= (-time_adj >> 6) + (-time_adj >> 7);
|
|
else
|
|
time_adj += (time_adj >> 6) + (time_adj >> 7);
|
|
#endif
|
|
}
|
|
|
|
/* in the NTP reference this is called "hardclock()" */
|
|
static void update_wall_time_one_tick(void)
|
|
{
|
|
long time_adjust_step, delta_nsec;
|
|
|
|
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;
|
|
}
|
|
delta_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 <= -FINENSEC) {
|
|
long ltemp = -time_phase >> (SHIFT_SCALE - 10);
|
|
time_phase += ltemp << (SHIFT_SCALE - 10);
|
|
delta_nsec -= ltemp;
|
|
}
|
|
else if (time_phase >= FINENSEC) {
|
|
long ltemp = time_phase >> (SHIFT_SCALE - 10);
|
|
time_phase -= ltemp << (SHIFT_SCALE - 10);
|
|
delta_nsec += ltemp;
|
|
}
|
|
xtime.tv_nsec += delta_nsec;
|
|
time_interpolator_update(delta_nsec);
|
|
|
|
/* Changes by adjtime() do not take effect till next tick. */
|
|
if (time_next_adjust != 0) {
|
|
time_adjust = time_next_adjust;
|
|
time_next_adjust = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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();
|
|
if (xtime.tv_nsec >= 1000000000) {
|
|
xtime.tv_nsec -= 1000000000;
|
|
xtime.tv_sec++;
|
|
second_overflow();
|
|
}
|
|
} while (ticks);
|
|
}
|
|
|
|
/*
|
|
* 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();
|
|
|
|
/* Note: this timer irq context must be accounted for as well. */
|
|
if (user_tick)
|
|
account_user_time(p, jiffies_to_cputime(1));
|
|
else
|
|
account_system_time(p, HARDIRQ_OFFSET, jiffies_to_cputime(1));
|
|
run_local_timers();
|
|
if (rcu_pending(cpu))
|
|
rcu_check_callbacks(cpu, user_tick);
|
|
scheduler_tick();
|
|
run_posix_cpu_timers(p);
|
|
}
|
|
|
|
/*
|
|
* 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];
|
|
|
|
EXPORT_SYMBOL(avenrun);
|
|
|
|
/*
|
|
* 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 = INITIAL_JIFFIES;
|
|
|
|
/*
|
|
* This read-write spinlock protects us from races in SMP while
|
|
* playing with xtime and avenrun.
|
|
*/
|
|
#ifndef ARCH_HAVE_XTIME_LOCK
|
|
seqlock_t xtime_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED;
|
|
|
|
EXPORT_SYMBOL(xtime_lock);
|
|
#endif
|
|
|
|
/*
|
|
* This function runs timers and the timer-tq in bottom half context.
|
|
*/
|
|
static void run_timer_softirq(struct softirq_action *h)
|
|
{
|
|
tvec_base_t *base = &__get_cpu_var(tvec_bases);
|
|
|
|
if (time_after_eq(jiffies, base->timer_jiffies))
|
|
__run_timers(base);
|
|
}
|
|
|
|
/*
|
|
* Called by the local, per-CPU timer interrupt on SMP.
|
|
*/
|
|
void run_local_timers(void)
|
|
{
|
|
raise_softirq(TIMER_SOFTIRQ);
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
calc_load(ticks);
|
|
}
|
|
|
|
/*
|
|
* The 64-bit jiffies value is not atomic - you MUST NOT read it
|
|
* without sampling the sequence number in xtime_lock.
|
|
* jiffies is defined in the linker script...
|
|
*/
|
|
|
|
void do_timer(struct pt_regs *regs)
|
|
{
|
|
jiffies_64++;
|
|
update_times();
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_SYS_ALARM
|
|
|
|
/*
|
|
* 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 ((!oldalarm && it_old.it_value.tv_usec) || it_old.it_value.tv_usec >= 500000)
|
|
oldalarm++;
|
|
return oldalarm;
|
|
}
|
|
|
|
#endif
|
|
|
|
#ifndef __alpha__
|
|
|
|
/*
|
|
* The Alpha uses getxpid, getxuid, and getxgid instead. Maybe this
|
|
* should be moved into arch/i386 instead?
|
|
*/
|
|
|
|
/**
|
|
* sys_getpid - return the thread group id of the current process
|
|
*
|
|
* Note, despite the name, this returns the tgid not the pid. The tgid and
|
|
* the pid are identical unless CLONE_THREAD was specified on clone() in
|
|
* which case the tgid is the same in all threads of the same group.
|
|
*
|
|
* This is SMP safe as current->tgid does not change.
|
|
*/
|
|
asmlinkage long sys_getpid(void)
|
|
{
|
|
return current->tgid;
|
|
}
|
|
|
|
/*
|
|
* Accessing ->group_leader->real_parent is not SMP-safe, it 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 (it was and remains a dereferencable kernel pointer
|
|
* no matter what): we just can't necessarily trust the result
|
|
* until we know that the parent pointer is valid.
|
|
*
|
|
* NOTE2: ->group_leader never changes from under us.
|
|
*/
|
|
asmlinkage long sys_getppid(void)
|
|
{
|
|
int pid;
|
|
struct task_struct *me = current;
|
|
struct task_struct *parent;
|
|
|
|
parent = me->group_leader->real_parent;
|
|
for (;;) {
|
|
pid = parent->tgid;
|
|
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
|
|
{
|
|
struct task_struct *old = parent;
|
|
|
|
/*
|
|
* Make sure we read the pid before re-reading the
|
|
* parent pointer:
|
|
*/
|
|
smp_rmb();
|
|
parent = me->group_leader->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.
|
|
*/
|
|
fastcall signed long __sched schedule_timeout(signed long timeout)
|
|
{
|
|
struct timer_list 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_singleshot_timer_sync(&timer);
|
|
|
|
timeout = expire - jiffies;
|
|
|
|
out:
|
|
return timeout < 0 ? 0 : timeout;
|
|
}
|
|
|
|
EXPORT_SYMBOL(schedule_timeout);
|
|
|
|
/* Thread ID - the internal kernel "pid" */
|
|
asmlinkage long sys_gettid(void)
|
|
{
|
|
return current->pid;
|
|
}
|
|
|
|
static long __sched nanosleep_restart(struct restart_block *restart)
|
|
{
|
|
unsigned long expire = restart->arg0, now = jiffies;
|
|
struct timespec __user *rmtp = (struct timespec __user *) restart->arg1;
|
|
long ret;
|
|
|
|
/* Did it expire while we handled signals? */
|
|
if (!time_after(expire, now))
|
|
return 0;
|
|
|
|
current->state = TASK_INTERRUPTIBLE;
|
|
expire = schedule_timeout(expire - now);
|
|
|
|
ret = 0;
|
|
if (expire) {
|
|
struct timespec t;
|
|
jiffies_to_timespec(expire, &t);
|
|
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
if (rmtp && copy_to_user(rmtp, &t, sizeof(t)))
|
|
ret = -EFAULT;
|
|
/* The 'restart' block is already filled in */
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
asmlinkage long sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
|
|
{
|
|
struct timespec t;
|
|
unsigned long expire;
|
|
long ret;
|
|
|
|
if (copy_from_user(&t, rqtp, sizeof(t)))
|
|
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);
|
|
|
|
ret = 0;
|
|
if (expire) {
|
|
struct restart_block *restart;
|
|
jiffies_to_timespec(expire, &t);
|
|
if (rmtp && copy_to_user(rmtp, &t, sizeof(t)))
|
|
return -EFAULT;
|
|
|
|
restart = ¤t_thread_info()->restart_block;
|
|
restart->fn = nanosleep_restart;
|
|
restart->arg0 = jiffies + expire;
|
|
restart->arg1 = (unsigned long) rmtp;
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* sys_sysinfo - fill in sysinfo struct
|
|
*/
|
|
asmlinkage long sys_sysinfo(struct sysinfo __user *info)
|
|
{
|
|
struct sysinfo val;
|
|
unsigned long mem_total, sav_total;
|
|
unsigned int mem_unit, bitcount;
|
|
unsigned long seq;
|
|
|
|
memset((char *)&val, 0, sizeof(struct sysinfo));
|
|
|
|
do {
|
|
struct timespec tp;
|
|
seq = read_seqbegin(&xtime_lock);
|
|
|
|
/*
|
|
* This is annoying. The below is the same thing
|
|
* posix_get_clock_monotonic() does, but it wants to
|
|
* take the lock which we want to cover the loads stuff
|
|
* too.
|
|
*/
|
|
|
|
getnstimeofday(&tp);
|
|
tp.tv_sec += wall_to_monotonic.tv_sec;
|
|
tp.tv_nsec += wall_to_monotonic.tv_nsec;
|
|
if (tp.tv_nsec - NSEC_PER_SEC >= 0) {
|
|
tp.tv_nsec = tp.tv_nsec - NSEC_PER_SEC;
|
|
tp.tv_sec++;
|
|
}
|
|
val.uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
|
|
|
|
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;
|
|
} while (read_seqretry(&xtime_lock, seq));
|
|
|
|
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;
|
|
}
|
|
|
|
static void __devinit init_timers_cpu(int cpu)
|
|
{
|
|
int j;
|
|
tvec_base_t *base;
|
|
|
|
base = &per_cpu(tvec_bases, cpu);
|
|
spin_lock_init(&base->t_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);
|
|
|
|
base->timer_jiffies = jiffies;
|
|
}
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static void migrate_timer_list(tvec_base_t *new_base, struct list_head *head)
|
|
{
|
|
struct timer_list *timer;
|
|
|
|
while (!list_empty(head)) {
|
|
timer = list_entry(head->next, struct timer_list, entry);
|
|
detach_timer(timer, 0);
|
|
timer->base = &new_base->t_base;
|
|
internal_add_timer(new_base, timer);
|
|
}
|
|
}
|
|
|
|
static void __devinit migrate_timers(int cpu)
|
|
{
|
|
tvec_base_t *old_base;
|
|
tvec_base_t *new_base;
|
|
int i;
|
|
|
|
BUG_ON(cpu_online(cpu));
|
|
old_base = &per_cpu(tvec_bases, cpu);
|
|
new_base = &get_cpu_var(tvec_bases);
|
|
|
|
local_irq_disable();
|
|
spin_lock(&new_base->t_base.lock);
|
|
spin_lock(&old_base->t_base.lock);
|
|
|
|
if (old_base->t_base.running_timer)
|
|
BUG();
|
|
for (i = 0; i < TVR_SIZE; i++)
|
|
migrate_timer_list(new_base, old_base->tv1.vec + i);
|
|
for (i = 0; i < TVN_SIZE; i++) {
|
|
migrate_timer_list(new_base, old_base->tv2.vec + i);
|
|
migrate_timer_list(new_base, old_base->tv3.vec + i);
|
|
migrate_timer_list(new_base, old_base->tv4.vec + i);
|
|
migrate_timer_list(new_base, old_base->tv5.vec + i);
|
|
}
|
|
|
|
spin_unlock(&old_base->t_base.lock);
|
|
spin_unlock(&new_base->t_base.lock);
|
|
local_irq_enable();
|
|
put_cpu_var(tvec_bases);
|
|
}
|
|
#endif /* CONFIG_HOTPLUG_CPU */
|
|
|
|
static int __devinit timer_cpu_notify(struct notifier_block *self,
|
|
unsigned long action, void *hcpu)
|
|
{
|
|
long cpu = (long)hcpu;
|
|
switch(action) {
|
|
case CPU_UP_PREPARE:
|
|
init_timers_cpu(cpu);
|
|
break;
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
case CPU_DEAD:
|
|
migrate_timers(cpu);
|
|
break;
|
|
#endif
|
|
default:
|
|
break;
|
|
}
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block __devinitdata timers_nb = {
|
|
.notifier_call = timer_cpu_notify,
|
|
};
|
|
|
|
|
|
void __init init_timers(void)
|
|
{
|
|
timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
|
|
(void *)(long)smp_processor_id());
|
|
register_cpu_notifier(&timers_nb);
|
|
open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
|
|
}
|
|
|
|
#ifdef CONFIG_TIME_INTERPOLATION
|
|
|
|
struct time_interpolator *time_interpolator;
|
|
static struct time_interpolator *time_interpolator_list;
|
|
static DEFINE_SPINLOCK(time_interpolator_lock);
|
|
|
|
static inline u64 time_interpolator_get_cycles(unsigned int src)
|
|
{
|
|
unsigned long (*x)(void);
|
|
|
|
switch (src)
|
|
{
|
|
case TIME_SOURCE_FUNCTION:
|
|
x = time_interpolator->addr;
|
|
return x();
|
|
|
|
case TIME_SOURCE_MMIO64 :
|
|
return readq((void __iomem *) time_interpolator->addr);
|
|
|
|
case TIME_SOURCE_MMIO32 :
|
|
return readl((void __iomem *) time_interpolator->addr);
|
|
|
|
default: return get_cycles();
|
|
}
|
|
}
|
|
|
|
static inline u64 time_interpolator_get_counter(void)
|
|
{
|
|
unsigned int src = time_interpolator->source;
|
|
|
|
if (time_interpolator->jitter)
|
|
{
|
|
u64 lcycle;
|
|
u64 now;
|
|
|
|
do {
|
|
lcycle = time_interpolator->last_cycle;
|
|
now = time_interpolator_get_cycles(src);
|
|
if (lcycle && time_after(lcycle, now))
|
|
return lcycle;
|
|
/* Keep track of the last timer value returned. The use of cmpxchg here
|
|
* will cause contention in an SMP environment.
|
|
*/
|
|
} while (unlikely(cmpxchg(&time_interpolator->last_cycle, lcycle, now) != lcycle));
|
|
return now;
|
|
}
|
|
else
|
|
return time_interpolator_get_cycles(src);
|
|
}
|
|
|
|
void time_interpolator_reset(void)
|
|
{
|
|
time_interpolator->offset = 0;
|
|
time_interpolator->last_counter = time_interpolator_get_counter();
|
|
}
|
|
|
|
#define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift)
|
|
|
|
unsigned long time_interpolator_get_offset(void)
|
|
{
|
|
/* If we do not have a time interpolator set up then just return zero */
|
|
if (!time_interpolator)
|
|
return 0;
|
|
|
|
return time_interpolator->offset +
|
|
GET_TI_NSECS(time_interpolator_get_counter(), time_interpolator);
|
|
}
|
|
|
|
#define INTERPOLATOR_ADJUST 65536
|
|
#define INTERPOLATOR_MAX_SKIP 10*INTERPOLATOR_ADJUST
|
|
|
|
static void time_interpolator_update(long delta_nsec)
|
|
{
|
|
u64 counter;
|
|
unsigned long offset;
|
|
|
|
/* If there is no time interpolator set up then do nothing */
|
|
if (!time_interpolator)
|
|
return;
|
|
|
|
/* The interpolator compensates for late ticks by accumulating
|
|
* the late time in time_interpolator->offset. A tick earlier than
|
|
* expected will lead to a reset of the offset and a corresponding
|
|
* jump of the clock forward. Again this only works if the
|
|
* interpolator clock is running slightly slower than the regular clock
|
|
* and the tuning logic insures that.
|
|
*/
|
|
|
|
counter = time_interpolator_get_counter();
|
|
offset = time_interpolator->offset + GET_TI_NSECS(counter, time_interpolator);
|
|
|
|
if (delta_nsec < 0 || (unsigned long) delta_nsec < offset)
|
|
time_interpolator->offset = offset - delta_nsec;
|
|
else {
|
|
time_interpolator->skips++;
|
|
time_interpolator->ns_skipped += delta_nsec - offset;
|
|
time_interpolator->offset = 0;
|
|
}
|
|
time_interpolator->last_counter = counter;
|
|
|
|
/* Tuning logic for time interpolator invoked every minute or so.
|
|
* Decrease interpolator clock speed if no skips occurred and an offset is carried.
|
|
* Increase interpolator clock speed if we skip too much time.
|
|
*/
|
|
if (jiffies % INTERPOLATOR_ADJUST == 0)
|
|
{
|
|
if (time_interpolator->skips == 0 && time_interpolator->offset > TICK_NSEC)
|
|
time_interpolator->nsec_per_cyc--;
|
|
if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0)
|
|
time_interpolator->nsec_per_cyc++;
|
|
time_interpolator->skips = 0;
|
|
time_interpolator->ns_skipped = 0;
|
|
}
|
|
}
|
|
|
|
static inline int
|
|
is_better_time_interpolator(struct time_interpolator *new)
|
|
{
|
|
if (!time_interpolator)
|
|
return 1;
|
|
return new->frequency > 2*time_interpolator->frequency ||
|
|
(unsigned long)new->drift < (unsigned long)time_interpolator->drift;
|
|
}
|
|
|
|
void
|
|
register_time_interpolator(struct time_interpolator *ti)
|
|
{
|
|
unsigned long flags;
|
|
|
|
/* Sanity check */
|
|
if (ti->frequency == 0 || ti->mask == 0)
|
|
BUG();
|
|
|
|
ti->nsec_per_cyc = ((u64)NSEC_PER_SEC << ti->shift) / ti->frequency;
|
|
spin_lock(&time_interpolator_lock);
|
|
write_seqlock_irqsave(&xtime_lock, flags);
|
|
if (is_better_time_interpolator(ti)) {
|
|
time_interpolator = ti;
|
|
time_interpolator_reset();
|
|
}
|
|
write_sequnlock_irqrestore(&xtime_lock, flags);
|
|
|
|
ti->next = time_interpolator_list;
|
|
time_interpolator_list = ti;
|
|
spin_unlock(&time_interpolator_lock);
|
|
}
|
|
|
|
void
|
|
unregister_time_interpolator(struct time_interpolator *ti)
|
|
{
|
|
struct time_interpolator *curr, **prev;
|
|
unsigned long flags;
|
|
|
|
spin_lock(&time_interpolator_lock);
|
|
prev = &time_interpolator_list;
|
|
for (curr = *prev; curr; curr = curr->next) {
|
|
if (curr == ti) {
|
|
*prev = curr->next;
|
|
break;
|
|
}
|
|
prev = &curr->next;
|
|
}
|
|
|
|
write_seqlock_irqsave(&xtime_lock, flags);
|
|
if (ti == time_interpolator) {
|
|
/* we lost the best time-interpolator: */
|
|
time_interpolator = NULL;
|
|
/* find the next-best interpolator */
|
|
for (curr = time_interpolator_list; curr; curr = curr->next)
|
|
if (is_better_time_interpolator(curr))
|
|
time_interpolator = curr;
|
|
time_interpolator_reset();
|
|
}
|
|
write_sequnlock_irqrestore(&xtime_lock, flags);
|
|
spin_unlock(&time_interpolator_lock);
|
|
}
|
|
#endif /* CONFIG_TIME_INTERPOLATION */
|
|
|
|
/**
|
|
* msleep - sleep safely even with waitqueue interruptions
|
|
* @msecs: Time in milliseconds to sleep for
|
|
*/
|
|
void msleep(unsigned int msecs)
|
|
{
|
|
unsigned long timeout = msecs_to_jiffies(msecs) + 1;
|
|
|
|
while (timeout) {
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
timeout = schedule_timeout(timeout);
|
|
}
|
|
}
|
|
|
|
EXPORT_SYMBOL(msleep);
|
|
|
|
/**
|
|
* msleep_interruptible - sleep waiting for signals
|
|
* @msecs: Time in milliseconds to sleep for
|
|
*/
|
|
unsigned long msleep_interruptible(unsigned int msecs)
|
|
{
|
|
unsigned long timeout = msecs_to_jiffies(msecs) + 1;
|
|
|
|
while (timeout && !signal_pending(current)) {
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
timeout = schedule_timeout(timeout);
|
|
}
|
|
return jiffies_to_msecs(timeout);
|
|
}
|
|
|
|
EXPORT_SYMBOL(msleep_interruptible);
|