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80a05b9ffa
The current logic which handles clock events programming failures can increase min_delta_ns unlimited and even can cause overflows. Sanitize it by: - prevent zero increase when min_delta_ns == 1 - limiting min_delta_ns to a jiffie - bail out if the jiffie limit is hit - add retries stats for /proc/timer_list so we can gather data Reported-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
155 lines
4.5 KiB
C
155 lines
4.5 KiB
C
/* linux/include/linux/clockchips.h
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*
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* This file contains the structure definitions for clockchips.
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*
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* If you are not a clockchip, or the time of day code, you should
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* not be including this file!
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*/
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#ifndef _LINUX_CLOCKCHIPS_H
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#define _LINUX_CLOCKCHIPS_H
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#ifdef CONFIG_GENERIC_CLOCKEVENTS_BUILD
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#include <linux/clocksource.h>
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#include <linux/cpumask.h>
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#include <linux/ktime.h>
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#include <linux/notifier.h>
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struct clock_event_device;
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/* Clock event mode commands */
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enum clock_event_mode {
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CLOCK_EVT_MODE_UNUSED = 0,
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CLOCK_EVT_MODE_SHUTDOWN,
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CLOCK_EVT_MODE_PERIODIC,
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CLOCK_EVT_MODE_ONESHOT,
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CLOCK_EVT_MODE_RESUME,
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};
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/* Clock event notification values */
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enum clock_event_nofitiers {
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CLOCK_EVT_NOTIFY_ADD,
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CLOCK_EVT_NOTIFY_BROADCAST_ON,
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CLOCK_EVT_NOTIFY_BROADCAST_OFF,
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CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
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CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
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CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
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CLOCK_EVT_NOTIFY_SUSPEND,
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CLOCK_EVT_NOTIFY_RESUME,
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CLOCK_EVT_NOTIFY_CPU_DYING,
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CLOCK_EVT_NOTIFY_CPU_DEAD,
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};
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/*
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* Clock event features
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*/
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#define CLOCK_EVT_FEAT_PERIODIC 0x000001
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#define CLOCK_EVT_FEAT_ONESHOT 0x000002
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/*
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* x86(64) specific misfeatures:
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*
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* - Clockevent source stops in C3 State and needs broadcast support.
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* - Local APIC timer is used as a dummy device.
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*/
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#define CLOCK_EVT_FEAT_C3STOP 0x000004
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#define CLOCK_EVT_FEAT_DUMMY 0x000008
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/**
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* struct clock_event_device - clock event device descriptor
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* @name: ptr to clock event name
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* @features: features
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* @max_delta_ns: maximum delta value in ns
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* @min_delta_ns: minimum delta value in ns
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* @mult: nanosecond to cycles multiplier
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* @shift: nanoseconds to cycles divisor (power of two)
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* @rating: variable to rate clock event devices
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* @irq: IRQ number (only for non CPU local devices)
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* @cpumask: cpumask to indicate for which CPUs this device works
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* @set_next_event: set next event function
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* @set_mode: set mode function
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* @event_handler: Assigned by the framework to be called by the low
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* level handler of the event source
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* @broadcast: function to broadcast events
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* @list: list head for the management code
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* @mode: operating mode assigned by the management code
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* @next_event: local storage for the next event in oneshot mode
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* @retries: number of forced programming retries
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*/
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struct clock_event_device {
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const char *name;
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unsigned int features;
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u64 max_delta_ns;
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u64 min_delta_ns;
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u32 mult;
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u32 shift;
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int rating;
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int irq;
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const struct cpumask *cpumask;
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int (*set_next_event)(unsigned long evt,
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struct clock_event_device *);
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void (*set_mode)(enum clock_event_mode mode,
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struct clock_event_device *);
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void (*event_handler)(struct clock_event_device *);
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void (*broadcast)(const struct cpumask *mask);
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struct list_head list;
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enum clock_event_mode mode;
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ktime_t next_event;
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unsigned long retries;
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};
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/*
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* Calculate a multiplication factor for scaled math, which is used to convert
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* nanoseconds based values to clock ticks:
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*
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* clock_ticks = (nanoseconds * factor) >> shift.
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*
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* div_sc is the rearranged equation to calculate a factor from a given clock
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* ticks / nanoseconds ratio:
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*
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* factor = (clock_ticks << shift) / nanoseconds
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*/
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static inline unsigned long div_sc(unsigned long ticks, unsigned long nsec,
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int shift)
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{
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uint64_t tmp = ((uint64_t)ticks) << shift;
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do_div(tmp, nsec);
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return (unsigned long) tmp;
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}
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/* Clock event layer functions */
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extern u64 clockevent_delta2ns(unsigned long latch,
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struct clock_event_device *evt);
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extern void clockevents_register_device(struct clock_event_device *dev);
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extern void clockevents_exchange_device(struct clock_event_device *old,
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struct clock_event_device *new);
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extern void clockevents_set_mode(struct clock_event_device *dev,
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enum clock_event_mode mode);
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extern int clockevents_register_notifier(struct notifier_block *nb);
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extern int clockevents_program_event(struct clock_event_device *dev,
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ktime_t expires, ktime_t now);
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extern void clockevents_handle_noop(struct clock_event_device *dev);
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static inline void
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clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
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{
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return clocks_calc_mult_shift(&ce->mult, &ce->shift, NSEC_PER_SEC,
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freq, minsec);
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}
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#ifdef CONFIG_GENERIC_CLOCKEVENTS
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extern void clockevents_notify(unsigned long reason, void *arg);
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#else
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# define clockevents_notify(reason, arg) do { } while (0)
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#endif
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#else /* CONFIG_GENERIC_CLOCKEVENTS_BUILD */
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#define clockevents_notify(reason, arg) do { } while (0)
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#endif
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#endif
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