timer-r0drv-linux.c@ 39008

Last change on this file since 39008 was 39008, checked in by vboxsync, 13 years ago
in_atomic() was added in 2.5.32 (i386).
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1	/* $Id: timer-r0drv-linux.c 39008 2011-10-17 14:54:31Z vboxsync $ */
2	/** @file
3	* IPRT - Timers, Ring-0 Driver, Linux.
4	*/
5
6	/*
7	* Copyright (C) 2006-2011 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*/
26
27
28	/*******************************************************************************
29	* Header Files *
30	*******************************************************************************/
31	#include "the-linux-kernel.h"
32	#include "internal/iprt.h"
33
34	#include <iprt/timer.h>
35	#include <iprt/time.h>
36	#include <iprt/mp.h>
37	#include <iprt/cpuset.h>
38	#include <iprt/spinlock.h>
39	#include <iprt/err.h>
40	#include <iprt/asm.h>
41	#include <iprt/assert.h>
42	#include <iprt/alloc.h>
43
44	#include "internal/magics.h"
45
46	/** @def RTTIMER_LINUX_WITH_HRTIMER
47	* Whether to use high resolution timers. */
48	#if !defined(RTTIMER_LINUX_WITH_HRTIMER) \
49	&& defined(IPRT_LINUX_HAS_HRTIMER)
50	# define RTTIMER_LINUX_WITH_HRTIMER
51	#endif
52
53	#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 31)
54	# define mod_timer_pinned mod_timer
55	# define HRTIMER_MODE_ABS_PINNED HRTIMER_MODE_ABS
56	#endif
57
58
59	/*******************************************************************************
60	* Structures and Typedefs *
61	*******************************************************************************/
62	/**
63	* Timer state machine.
64	*
65	* This is used to try handle the issues with MP events and
66	* timers that runs on all CPUs. It's relatively nasty :-/
67	*/
68	typedef enum RTTIMERLNXSTATE
69	{
70	/** Stopped. */
71	RTTIMERLNXSTATE_STOPPED = 0,
72	/** Transient state; next ACTIVE. */
73	RTTIMERLNXSTATE_STARTING,
74	/** Transient state; next ACTIVE. (not really necessary) */
75	RTTIMERLNXSTATE_MP_STARTING,
76	/** Active. */
77	RTTIMERLNXSTATE_ACTIVE,
78	/** Active and in callback; next ACTIVE, STOPPED or CALLBACK_DESTROYING. */
79	RTTIMERLNXSTATE_CALLBACK,
80	/** Stopped while in the callback; next STOPPED. */
81	RTTIMERLNXSTATE_CB_STOPPING,
82	/** Restarted while in the callback; next ACTIVE, STOPPED, DESTROYING. */
83	RTTIMERLNXSTATE_CB_RESTARTING,
84	/** The callback shall destroy the timer; next STOPPED. */
85	RTTIMERLNXSTATE_CB_DESTROYING,
86	/** Transient state; next STOPPED. */
87	RTTIMERLNXSTATE_STOPPING,
88	/** Transient state; next STOPPED. */
89	RTTIMERLNXSTATE_MP_STOPPING,
90	/** The usual 32-bit hack. */
91	RTTIMERLNXSTATE_32BIT_HACK = 0x7fffffff
92	} RTTIMERLNXSTATE;
93
94
95	/**
96	* A Linux sub-timer.
97	*/
98	typedef struct RTTIMERLNXSUBTIMER
99	{
100	/** Timer specific data. */
101	union
102	{
103	#if defined(RTTIMER_LINUX_WITH_HRTIMER)
104	/** High resolution timer. */
105	struct
106	{
107	/** The linux timer structure. */
108	struct hrtimer LnxTimer;
109	} Hr;
110	#endif
111	/** Standard timer. */
112	struct
113	{
114	/** The linux timer structure. */
115	struct timer_list LnxTimer;
116	/** The start of the current run (ns).
117	* This is used to calculate when the timer ought to fire the next time. */
118	uint64_t u64NextTS;
119	/** The u64NextTS in jiffies. */
120	unsigned long ulNextJiffies;
121	/** Set when starting or changing the timer so that u64StartTs
122	* and u64NextTS gets reinitialized (eliminating some jitter). */
123	bool volatile fFirstAfterChg;
124	} Std;
125	} u;
126	/** The current tick number. */
127	uint64_t iTick;
128	/** Restart the single shot timer at this specific time.
129	* Used when a single shot timer is restarted from the callback. */
130	uint64_t volatile uNsRestartAt;
131	/** Pointer to the parent timer. */
132	PRTTIMER pParent;
133	/** The current sub-timer state. */
134	RTTIMERLNXSTATE volatile enmState;
135	} RTTIMERLNXSUBTIMER;
136	/** Pointer to a linux sub-timer. */
137	typedef RTTIMERLNXSUBTIMER *PRTTIMERLNXSUBTIMER;
138
139
140	/**
141	* The internal representation of an Linux timer handle.
142	*/
143	typedef struct RTTIMER
144	{
145	/** Magic.
146	* This is RTTIMER_MAGIC, but changes to something else before the timer
147	* is destroyed to indicate clearly that thread should exit. */
148	uint32_t volatile u32Magic;
149	/** Spinlock synchronizing the fSuspended and MP event handling.
150	* This is NIL_RTSPINLOCK if cCpus == 1. */
151	RTSPINLOCK hSpinlock;
152	/** Flag indicating that the timer is suspended. */
153	bool volatile fSuspended;
154	/** Whether the timer must run on one specific CPU or not. */
155	bool fSpecificCpu;
156	#ifdef CONFIG_SMP
157	/** Whether the timer must run on all CPUs or not. */
158	bool fAllCpus;
159	#endif /* else: All -> specific on non-SMP kernels */
160	/** Whether it is a high resolution timer or a standard one. */
161	bool fHighRes;
162	/** The id of the CPU it must run on if fSpecificCpu is set. */
163	RTCPUID idCpu;
164	/** The number of CPUs this timer should run on. */
165	RTCPUID cCpus;
166	/** Callback. */
167	PFNRTTIMER pfnTimer;
168	/** User argument. */
169	void *pvUser;
170	/** The timer interval. 0 if one-shot. */
171	uint64_t volatile u64NanoInterval;
172	/** This is set to the number of jiffies between ticks if the interval is
173	* an exact number of jiffies. (Standard timers only.) */
174	unsigned long volatile cJiffies;
175	/** The change interval spinlock for standard timers only. */
176	spinlock_t ChgIntLock;
177	/** Workqueue item for delayed destruction. */
178	RTR0LNXWORKQUEUEITEM DtorWorkqueueItem;
179	/** Sub-timers.
180	* Normally there is just one, but for RTTIMER_FLAGS_CPU_ALL this will contain
181	* an entry for all possible cpus. In that case the index will be the same as
182	* for the RTCpuSet. */
183	RTTIMERLNXSUBTIMER aSubTimers[1];
184	} RTTIMER;
185
186
187	/**
188	* A rtTimerLinuxStartOnCpu and rtTimerLinuxStartOnCpu argument package.
189	*/
190	typedef struct RTTIMERLINUXSTARTONCPUARGS
191	{
192	/** The current time (RTTimeSystemNanoTS). */
193	uint64_t u64Now;
194	/** When to start firing (delta). */
195	uint64_t u64First;
196	} RTTIMERLINUXSTARTONCPUARGS;
197	/** Pointer to a rtTimerLinuxStartOnCpu argument package. */
198	typedef RTTIMERLINUXSTARTONCPUARGS *PRTTIMERLINUXSTARTONCPUARGS;
199
200
201	/*******************************************************************************
202	* Internal Functions *
203	*******************************************************************************/
204	#ifdef CONFIG_SMP
205	static DECLCALLBACK(void) rtTimerLinuxMpEvent(RTMPEVENT enmEvent, RTCPUID idCpu, void *pvUser);
206	#endif
207
208	#if 0
209	#define DEBUG_HACKING
210	#include <iprt/string.h>
211	#include <iprt/asm-amd64-x86.h>
212	static void myLogBackdoorPrintf(const char *pszFormat, ...)
213	{
214	char szTmp[256];
215	va_list args;
216	size_t cb;
217
218	cb = RTStrPrintf(szTmp, sizeof(szTmp) - 10, "%d: ", RTMpCpuId());
219	va_start(args, pszFormat);
220	cb += RTStrPrintfV(&szTmp[cb], sizeof(szTmp) - cb, pszFormat, args);
221	va_end(args);
222
223	ASMOutStrU8(0x504, (uint8_t *)&szTmp[0], cb);
224	}
225	# define RTAssertMsg1Weak(pszExpr, uLine, pszFile, pszFunction) \
226	myLogBackdoorPrintf("\n!!Guest Assertion failed!!\n%s(%d) %s\n%s\n", uLine, pszFile, pszFunction, (pszExpr))
227	# define RTAssertMsg2Weak myLogBackdoorPrintf
228	# define RTTIMERLNX_LOG(a) myLogBackdoorPrintf a
229	#else
230	# define RTTIMERLNX_LOG(a) do { } while (0)
231	#endif
232
233	/**
234	* Sets the state.
235	*/
236	DECLINLINE(void) rtTimerLnxSetState(RTTIMERLNXSTATE volatile *penmState, RTTIMERLNXSTATE enmNewState)
237	{
238	#ifdef DEBUG_HACKING
239	RTTIMERLNX_LOG(("set %d -> %d\n", *penmState, enmNewState));
240	#endif
241	ASMAtomicWriteU32((uint32_t volatile *)penmState, enmNewState);
242	}
243
244
245	/**
246	* Sets the state if it has a certain value.
247	*
248	* @return true if xchg was done.
249	* @return false if xchg wasn't done.
250	*/
251	#ifdef DEBUG_HACKING
252	#define rtTimerLnxCmpXchgState(penmState, enmNewState, enmCurState) rtTimerLnxCmpXchgStateDebug(penmState, enmNewState, enmCurState, __LINE__)
253	static bool rtTimerLnxCmpXchgStateDebug(RTTIMERLNXSTATE volatile *penmState, RTTIMERLNXSTATE enmNewState,
254	RTTIMERLNXSTATE enmCurState, uint32_t uLine)
255	{
256	RTTIMERLNXSTATE enmOldState = enmCurState;
257	bool fRc = ASMAtomicCmpXchgExU32((uint32_t volatile )penmState, enmNewState, enmCurState, (uint32_t )&enmOldState);
258	RTTIMERLNX_LOG(("cxg %d -> %d - %d at %u\n", enmOldState, enmNewState, fRc, uLine));
259	return fRc;
260	}
261	#else
262	DECLINLINE(bool) rtTimerLnxCmpXchgState(RTTIMERLNXSTATE volatile *penmState, RTTIMERLNXSTATE enmNewState,
263	RTTIMERLNXSTATE enmCurState)
264	{
265	return ASMAtomicCmpXchgU32((uint32_t volatile *)penmState, enmNewState, enmCurState);
266	}
267	#endif
268
269
270	/**
271	* Gets the state.
272	*/
273	DECLINLINE(RTTIMERLNXSTATE) rtTimerLnxGetState(RTTIMERLNXSTATE volatile *penmState)
274	{
275	return (RTTIMERLNXSTATE)ASMAtomicUoReadU32((uint32_t volatile *)penmState);
276	}
277
278	#ifdef RTTIMER_LINUX_WITH_HRTIMER
279
280	/**
281	* Converts a nano second time stamp to ktime_t.
282	*
283	* ASSUMES RTTimeSystemNanoTS() is implemented using ktime_get_ts().
284	*
285	* @returns ktime_t.
286	* @param cNanoSecs Nanoseconds.
287	*/
288	DECLINLINE(ktime_t) rtTimerLnxNanoToKt(uint64_t cNanoSecs)
289	{
290	/* With some luck the compiler optimizes the division out of this... (Bet it doesn't.) */
291	return ktime_set(cNanoSecs / 1000000000, cNanoSecs % 1000000000);
292	}
293
294	/**
295	* Converts ktime_t to a nano second time stamp.
296	*
297	* ASSUMES RTTimeSystemNanoTS() is implemented using ktime_get_ts().
298	*
299	* @returns nano second time stamp.
300	* @param Kt ktime_t.
301	*/
302	DECLINLINE(uint64_t) rtTimerLnxKtToNano(ktime_t Kt)
303	{
304	return ktime_to_ns(Kt);
305	}
306
307	#endif /* RTTIMER_LINUX_WITH_HRTIMER */
308
309	/**
310	* Converts a nano second interval to jiffies.
311	*
312	* @returns Jiffies.
313	* @param cNanoSecs Nanoseconds.
314	*/
315	DECLINLINE(unsigned long) rtTimerLnxNanoToJiffies(uint64_t cNanoSecs)
316	{
317	/* this can be made even better... */
318	if (cNanoSecs > (uint64_t)TICK_NSEC * MAX_JIFFY_OFFSET)
319	return MAX_JIFFY_OFFSET;
320	# if ARCH_BITS == 32
321	if (RT_LIKELY(cNanoSecs <= UINT32_MAX))
322	return ((uint32_t)cNanoSecs + (TICK_NSEC-1)) / TICK_NSEC;
323	# endif
324	return (cNanoSecs + (TICK_NSEC-1)) / TICK_NSEC;
325	}
326
327
328	/**
329	* Starts a sub-timer (RTTimerStart).
330	*
331	* @param pSubTimer The sub-timer to start.
332	* @param u64Now The current timestamp (RTTimeSystemNanoTS()).
333	* @param u64First The interval from u64Now to the first time the timer should fire.
334	* @param fPinned true = timer pinned to a specific CPU,
335	* false = timer can migrate between CPUs
336	* @param fHighRes Whether the user requested a high resolution timer or not.
337	* @param enmOldState The old timer state.
338	*/
339	static void rtTimerLnxStartSubTimer(PRTTIMERLNXSUBTIMER pSubTimer, uint64_t u64Now, uint64_t u64First,
340	bool fPinned, bool fHighRes)
341	{
342	/*
343	* Calc when it should start firing.
344	*/
345	uint64_t u64NextTS = u64Now + u64First;
346	if (!fHighRes)
347	pSubTimer->u.Std.u64NextTS = u64NextTS;
348	RTTIMERLNX_LOG(("startsubtimer %p\n", pSubTimer->pParent));
349
350	pSubTimer->iTick = 0;
351
352	#ifdef RTTIMER_LINUX_WITH_HRTIMER
353	if (fHighRes)
354	hrtimer_start(&pSubTimer->u.Hr.LnxTimer, rtTimerLnxNanoToKt(u64NextTS),
355	fPinned ? HRTIMER_MODE_ABS_PINNED : HRTIMER_MODE_ABS);
356	else
357	#endif
358	{
359	unsigned long cJiffies = !u64First ? 0 : rtTimerLnxNanoToJiffies(u64First);
360	pSubTimer->u.Std.ulNextJiffies = jiffies + cJiffies;
361	pSubTimer->u.Std.fFirstAfterChg = true;
362	#ifdef CONFIG_SMP
363	if (fPinned)
364	mod_timer_pinned(&pSubTimer->u.Std.LnxTimer, pSubTimer->u.Std.ulNextJiffies);
365	else
366	#endif
367	mod_timer(&pSubTimer->u.Std.LnxTimer, pSubTimer->u.Std.ulNextJiffies);
368	}
369
370	/* Be a bit careful here since we could be racing the callback. */
371	if (!rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_ACTIVE, RTTIMERLNXSTATE_STARTING))
372	rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_ACTIVE, RTTIMERLNXSTATE_MP_STARTING);
373	}
374
375
376	/**
377	* Stops a sub-timer (RTTimerStart and rtTimerLinuxMpEvent()).
378	*
379	* The caller has already changed the state, so we will not be in a callback
380	* situation wrt to the calling thread.
381	*
382	* @param pSubTimer The sub-timer.
383	* @param fHighRes Whether the user requested a high resolution timer or not.
384	*/
385	static void rtTimerLnxStopSubTimer(PRTTIMERLNXSUBTIMER pSubTimer, bool fHighRes)
386	{
387	RTTIMERLNX_LOG(("stopsubtimer %p %d\n", pSubTimer->pParent, fHighRes));
388	#ifdef RTTIMER_LINUX_WITH_HRTIMER
389	if (fHighRes)
390	{
391	/* There is no equivalent to del_timer in the hrtimer API,
392	hrtimer_cancel() == del_timer_sync(). Just like the WARN_ON in
393	del_timer_sync() asserts, waiting for a timer callback to complete
394	is deadlock prone, so don't do it. */
395	int rc = hrtimer_try_to_cancel(&pSubTimer->u.Hr.LnxTimer);
396	if (rc < 0)
397	{
398	hrtimer_start(&pSubTimer->u.Hr.LnxTimer, ktime_set(KTIME_SEC_MAX, 0), HRTIMER_MODE_ABS);
399	hrtimer_try_to_cancel(&pSubTimer->u.Hr.LnxTimer);
400	}
401	}
402	else
403	#endif
404	del_timer(&pSubTimer->u.Std.LnxTimer);
405
406	rtTimerLnxSetState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED);
407	}
408
409
410	/**
411	* Used by RTTimerDestroy and rtTimerLnxCallbackDestroy to do the actual work.
412	*
413	* @param pTimer The timer in question.
414	*/
415	static void rtTimerLnxDestroyIt(PRTTIMER pTimer)
416	{
417	RTSPINLOCK hSpinlock = pTimer->hSpinlock;
418	RTCPUID iCpu;
419	Assert(pTimer->fSuspended);
420	RTTIMERLNX_LOG(("destroyit %p\n", pTimer));
421
422	/*
423	* Remove the MP notifications first because it'll reduce the risk of
424	* us overtaking any MP event that might theoretically be racing us here.
425	*/
426	#ifdef CONFIG_SMP
427	if ( pTimer->cCpus > 1
428	&& hSpinlock != NIL_RTSPINLOCK)
429	{
430	int rc = RTMpNotificationDeregister(rtTimerLinuxMpEvent, pTimer);
431	AssertRC(rc);
432	}
433	#endif /* CONFIG_SMP */
434
435	/*
436	* Invalidate the handle.
437	*/
438	ASMAtomicWriteU32(&pTimer->u32Magic, ~RTTIMER_MAGIC);
439
440	/*
441	* Make sure all timers have stopped executing since we're stopping them in
442	* an asynchronous manner up in rtTimerLnxStopSubTimer.
443	*/
444	iCpu = pTimer->cCpus;
445	while (iCpu-- > 0)
446	{
447	#ifdef RTTIMER_LINUX_WITH_HRTIMER
448	if (pTimer->fHighRes)
449	hrtimer_cancel(&pTimer->aSubTimers[iCpu].u.Hr.LnxTimer);
450	else
451	#endif
452	del_timer_sync(&pTimer->aSubTimers[iCpu].u.Std.LnxTimer);
453	}
454
455	/*
456	* Finally, free the resources.
457	*/
458	RTMemFreeEx(pTimer, RT_OFFSETOF(RTTIMER, aSubTimers[pTimer->cCpus]));
459	if (hSpinlock != NIL_RTSPINLOCK)
460	RTSpinlockDestroy(hSpinlock);
461	}
462
463
464	/**
465	* Workqueue callback (no DECLCALLBACK!) for deferred destruction.
466	*
467	* @param pWork Pointer to the DtorWorkqueueItem member of our timer
468	* structure.
469	*/
470	static void rtTimerLnxDestroyDeferred(RTR0LNXWORKQUEUEITEM *pWork)
471	{
472	PRTTIMER pTimer = RT_FROM_MEMBER(pWork, RTTIMER, DtorWorkqueueItem);
473	rtTimerLnxDestroyIt(pTimer);
474	}
475
476
477	/**
478	* Called when the timer was destroyed by the callback function.
479	*
480	* @param pTimer The timer.
481	* @param pSubTimer The sub-timer which we're handling, the state of this
482	* will be RTTIMERLNXSTATE_CALLBACK_DESTROYING.
483	*/
484	static void rtTimerLnxCallbackDestroy(PRTTIMER pTimer, PRTTIMERLNXSUBTIMER pSubTimer)
485	{
486	/*
487	* If it's an omni timer, the last dude does the destroying.
488	*/
489	if (pTimer->cCpus > 1)
490	{
491	uint32_t iCpu = pTimer->cCpus;
492	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
493	RTSpinlockAcquire(pTimer->hSpinlock, &Tmp);
494
495	Assert(pSubTimer->enmState == RTTIMERLNXSTATE_CB_DESTROYING);
496	rtTimerLnxSetState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED);
497
498	while (iCpu-- > 0)
499	if (rtTimerLnxGetState(&pTimer->aSubTimers[iCpu].enmState) != RTTIMERLNXSTATE_STOPPED)
500	{
501	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
502	return;
503	}
504
505	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
506	}
507
508	/*
509	* Destroying a timer from the callback is unsafe since the callout code
510	* might be touching the timer structure upon return (hrtimer does!). So,
511	* we have to defer the actual destruction to the IRPT workqueue.
512	*/
513	rtR0LnxWorkqueuePush(&pTimer->DtorWorkqueueItem, rtTimerLnxDestroyDeferred);
514	}
515
516
517	#ifdef CONFIG_SMP
518	/**
519	* Deal with a sub-timer that has migrated.
520	*
521	* @param pTimer The timer.
522	* @param pSubTimer The sub-timer.
523	*/
524	static void rtTimerLnxCallbackHandleMigration(PRTTIMER pTimer, PRTTIMERLNXSUBTIMER pSubTimer)
525	{
526	RTTIMERLNXSTATE enmState;
527	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
528	if (pTimer->cCpus > 1)
529	RTSpinlockAcquire(pTimer->hSpinlock, &Tmp);
530
531	do
532	{
533	enmState = rtTimerLnxGetState(&pSubTimer->enmState);
534	switch (enmState)
535	{
536	case RTTIMERLNXSTATE_STOPPING:
537	case RTTIMERLNXSTATE_MP_STOPPING:
538	enmState = RTTIMERLNXSTATE_STOPPED;
539	case RTTIMERLNXSTATE_STOPPED:
540	break;
541
542	default:
543	AssertMsgFailed(("%d\n", enmState));
544	case RTTIMERLNXSTATE_STARTING:
545	case RTTIMERLNXSTATE_MP_STARTING:
546	case RTTIMERLNXSTATE_ACTIVE:
547	case RTTIMERLNXSTATE_CALLBACK:
548	case RTTIMERLNXSTATE_CB_STOPPING:
549	case RTTIMERLNXSTATE_CB_RESTARTING:
550	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED, enmState))
551	enmState = RTTIMERLNXSTATE_STOPPED;
552	break;
553
554	case RTTIMERLNXSTATE_CB_DESTROYING:
555	{
556	if (pTimer->cCpus > 1)
557	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
558
559	rtTimerLnxCallbackDestroy(pTimer, pSubTimer);
560	return;
561	}
562	}
563	} while (enmState != RTTIMERLNXSTATE_STOPPED);
564
565	if (pTimer->cCpus > 1)
566	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
567	}
568	#endif /* CONFIG_SMP */
569
570
571	/**
572	* The slow path of rtTimerLnxChangeToCallbackState.
573	*
574	* @returns true if changed successfully, false if not.
575	* @param pSubTimer The sub-timer.
576	*/
577	static bool rtTimerLnxChangeToCallbackStateSlow(PRTTIMERLNXSUBTIMER pSubTimer)
578	{
579	for (;;)
580	{
581	RTTIMERLNXSTATE enmState = rtTimerLnxGetState(&pSubTimer->enmState);
582	switch (enmState)
583	{
584	case RTTIMERLNXSTATE_ACTIVE:
585	case RTTIMERLNXSTATE_STARTING:
586	case RTTIMERLNXSTATE_MP_STARTING:
587	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_CALLBACK, enmState))
588	return true;
589	break;
590
591	case RTTIMERLNXSTATE_CALLBACK:
592	case RTTIMERLNXSTATE_CB_STOPPING:
593	case RTTIMERLNXSTATE_CB_RESTARTING:
594	case RTTIMERLNXSTATE_CB_DESTROYING:
595	AssertMsgFailed(("%d\n", enmState));
596	default:
597	return false;
598	}
599	ASMNopPause();
600	}
601	}
602
603
604	/**
605	* Tries to change the sub-timer state to 'callback'.
606	*
607	* @returns true if changed successfully, false if not.
608	* @param pSubTimer The sub-timer.
609	*/
610	DECLINLINE(bool) rtTimerLnxChangeToCallbackState(PRTTIMERLNXSUBTIMER pSubTimer)
611	{
612	if (RT_LIKELY(rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_CALLBACK, RTTIMERLNXSTATE_ACTIVE)))
613	return true;
614	return rtTimerLnxChangeToCallbackStateSlow(pSubTimer);
615	}
616
617
618	#ifdef RTTIMER_LINUX_WITH_HRTIMER
619	/**
620	* Timer callback function for high resolution timers.
621	*
622	* @returns HRTIMER_NORESTART or HRTIMER_RESTART depending on whether it's a
623	* one-shot or interval timer.
624	* @param pHrTimer Pointer to the sub-timer structure.
625	*/
626	static enum hrtimer_restart rtTimerLinuxHrCallback(struct hrtimer *pHrTimer)
627	{
628	PRTTIMERLNXSUBTIMER pSubTimer = RT_FROM_MEMBER(pHrTimer, RTTIMERLNXSUBTIMER, u.Hr.LnxTimer);
629	PRTTIMER pTimer = pSubTimer->pParent;
630
631
632	RTTIMERLNX_LOG(("hrcallback %p\n", pTimer));
633	if (RT_UNLIKELY(!rtTimerLnxChangeToCallbackState(pSubTimer)))
634	return HRTIMER_NORESTART;
635
636	#ifdef CONFIG_SMP
637	/*
638	* Check for unwanted migration.
639	*/
640	if (pTimer->fAllCpus \|\| pTimer->fSpecificCpu)
641	{
642	RTCPUID idCpu = RTMpCpuId();
643	if (RT_UNLIKELY( pTimer->fAllCpus
644	? (RTCPUID)(pSubTimer - &pTimer->aSubTimers[0]) != idCpu
645	: pTimer->idCpu != idCpu))
646	{
647	rtTimerLnxCallbackHandleMigration(pTimer, pSubTimer);
648	return HRTIMER_NORESTART;
649	}
650	}
651	#endif
652
653	if (pTimer->u64NanoInterval)
654	{
655	/*
656	* Periodic timer, run it and update the native timer afterwards so
657	* we can handle RTTimerStop and RTTimerChangeInterval from the
658	* callback as well as a racing control thread.
659	*/
660	pTimer->pfnTimer(pTimer, pTimer->pvUser, ++pSubTimer->iTick);
661	hrtimer_add_expires_ns(&pSubTimer->u.Hr.LnxTimer, ASMAtomicReadU64(&pTimer->u64NanoInterval));
662	if (RT_LIKELY(rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_ACTIVE, RTTIMERLNXSTATE_CALLBACK)))
663	return HRTIMER_RESTART;
664	}
665	else
666	{
667	/*
668	* One shot timer (no omni), stop it before dispatching it.
669	* Allow RTTimerStart as well as RTTimerDestroy to be called from
670	* the callback.
671	*/
672	ASMAtomicWriteBool(&pTimer->fSuspended, true);
673	pTimer->pfnTimer(pTimer, pTimer->pvUser, ++pSubTimer->iTick);
674	if (RT_LIKELY(rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED, RTTIMERLNXSTATE_CALLBACK)))
675	return HRTIMER_NORESTART;
676	}
677
678	/*
679	* Some state change occurred while we were in the callback routine.
680	*/
681	for (;;)
682	{
683	RTTIMERLNXSTATE enmState = rtTimerLnxGetState(&pSubTimer->enmState);
684	switch (enmState)
685	{
686	case RTTIMERLNXSTATE_CB_DESTROYING:
687	rtTimerLnxCallbackDestroy(pTimer, pSubTimer);
688	return HRTIMER_NORESTART;
689
690	case RTTIMERLNXSTATE_CB_STOPPING:
691	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED, RTTIMERLNXSTATE_CB_STOPPING))
692	return HRTIMER_NORESTART;
693	break;
694
695	case RTTIMERLNXSTATE_CB_RESTARTING:
696	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_ACTIVE, RTTIMERLNXSTATE_CB_RESTARTING))
697	{
698	pSubTimer->iTick = 0;
699	hrtimer_set_expires(&pSubTimer->u.Hr.LnxTimer, rtTimerLnxNanoToKt(pSubTimer->uNsRestartAt));
700	return HRTIMER_RESTART;
701	}
702	break;
703
704	default:
705	AssertMsgFailed(("%d\n", enmState));
706	return HRTIMER_NORESTART;
707	}
708	ASMNopPause();
709	}
710	}
711	#endif /* RTTIMER_LINUX_WITH_HRTIMER */
712
713
714	/**
715	* Timer callback function for standard timers.
716	*
717	* @param ulUser Address of the sub-timer structure.
718	*/
719	static void rtTimerLinuxStdCallback(unsigned long ulUser)
720	{
721	PRTTIMERLNXSUBTIMER pSubTimer = (PRTTIMERLNXSUBTIMER)ulUser;
722	PRTTIMER pTimer = pSubTimer->pParent;
723
724	RTTIMERLNX_LOG(("stdcallback %p\n", pTimer));
725	if (RT_UNLIKELY(!rtTimerLnxChangeToCallbackState(pSubTimer)))
726	return;
727
728	#ifdef CONFIG_SMP
729	/*
730	* Check for unwanted migration.
731	*/
732	if (pTimer->fAllCpus \|\| pTimer->fSpecificCpu)
733	{
734	RTCPUID idCpu = RTMpCpuId();
735	if (RT_UNLIKELY( pTimer->fAllCpus
736	? (RTCPUID)(pSubTimer - &pTimer->aSubTimers[0]) != idCpu
737	: pTimer->idCpu != idCpu))
738	{
739	rtTimerLnxCallbackHandleMigration(pTimer, pSubTimer);
740	return;
741	}
742	}
743	#endif
744
745	if (pTimer->u64NanoInterval)
746	{
747	/*
748	* Interval timer, calculate the next timeout.
749	*
750	* The first time around, we'll re-adjust the u.Std.u64NextTS to
751	* try prevent some jittering if we were started at a bad time.
752	*/
753	const uint64_t iTick = ++pSubTimer->iTick;
754	uint64_t u64NanoInterval;
755	unsigned long cJiffies;
756	unsigned long flFlags;
757
758	spin_lock_irqsave(&pTimer->ChgIntLock, flFlags);
759	u64NanoInterval = pTimer->u64NanoInterval;
760	cJiffies = pTimer->cJiffies;
761	if (RT_UNLIKELY(pSubTimer->u.Std.fFirstAfterChg))
762	{
763	pSubTimer->u.Std.fFirstAfterChg = false;
764	pSubTimer->u.Std.u64NextTS = RTTimeSystemNanoTS();
765	pSubTimer->u.Std.ulNextJiffies = jiffies;
766	}
767	spin_unlock_irqrestore(&pTimer->ChgIntLock, flFlags);
768
769	pSubTimer->u.Std.u64NextTS += u64NanoInterval;
770	if (cJiffies)
771	{
772	pSubTimer->u.Std.ulNextJiffies += cJiffies;
773	/* Prevent overflows when the jiffies counter wraps around.
774	* Special thanks to Ken Preslan for helping debugging! */
775	while (time_before(pSubTimer->u.Std.ulNextJiffies, jiffies))
776	{
777	pSubTimer->u.Std.ulNextJiffies += cJiffies;
778	pSubTimer->u.Std.u64NextTS += u64NanoInterval;
779	}
780	}
781	else
782	{
783	const uint64_t u64NanoTS = RTTimeSystemNanoTS();
784	while (pSubTimer->u.Std.u64NextTS < u64NanoTS)
785	pSubTimer->u.Std.u64NextTS += u64NanoInterval;
786	pSubTimer->u.Std.ulNextJiffies = jiffies + rtTimerLnxNanoToJiffies(pSubTimer->u.Std.u64NextTS - u64NanoTS);
787	}
788
789	/*
790	* Run the timer and re-arm it unless the state changed .
791	* .
792	* We must re-arm it afterwards as we're not in a position to undo this .
793	* operation if for instance someone stopped or destroyed us while we .
794	* were in the callback. (Linux takes care of any races here.)
795	*/
796	pTimer->pfnTimer(pTimer, pTimer->pvUser, iTick);
797	if (RT_LIKELY(rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_ACTIVE, RTTIMERLNXSTATE_CALLBACK)))
798	{
799	#ifdef CONFIG_SMP
800	if (pTimer->fSpecificCpu \|\| pTimer->fAllCpus)
801	mod_timer_pinned(&pSubTimer->u.Std.LnxTimer, pSubTimer->u.Std.ulNextJiffies);
802	else
803	#endif
804	mod_timer(&pSubTimer->u.Std.LnxTimer, pSubTimer->u.Std.ulNextJiffies);
805	return;
806	}
807	}
808	else
809	{
810	/*
811	* One shot timer, stop it before dispatching it.
812	* Allow RTTimerStart as well as RTTimerDestroy to be called from
813	* the callback.
814	*/
815	ASMAtomicWriteBool(&pTimer->fSuspended, true);
816	pTimer->pfnTimer(pTimer, pTimer->pvUser, ++pSubTimer->iTick);
817	if (RT_LIKELY(rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED, RTTIMERLNXSTATE_CALLBACK)))
818	return;
819	}
820
821	/*
822	* Some state change occurred while we were in the callback routine.
823	*/
824	for (;;)
825	{
826	RTTIMERLNXSTATE enmState = rtTimerLnxGetState(&pSubTimer->enmState);
827	switch (enmState)
828	{
829	case RTTIMERLNXSTATE_CB_DESTROYING:
830	rtTimerLnxCallbackDestroy(pTimer, pSubTimer);
831	return;
832
833	case RTTIMERLNXSTATE_CB_STOPPING:
834	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED, RTTIMERLNXSTATE_CB_STOPPING))
835	return;
836	break;
837
838	case RTTIMERLNXSTATE_CB_RESTARTING:
839	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_ACTIVE, RTTIMERLNXSTATE_CB_RESTARTING))
840	{
841	uint64_t u64NanoTS;
842	uint64_t u64NextTS;
843	unsigned long flFlags;
844
845	spin_lock_irqsave(&pTimer->ChgIntLock, flFlags);
846	u64NextTS = pSubTimer->uNsRestartAt;
847	u64NanoTS = RTTimeSystemNanoTS();
848	pSubTimer->iTick = 0;
849	pSubTimer->u.Std.u64NextTS = u64NextTS;
850	pSubTimer->u.Std.fFirstAfterChg = true;
851	pSubTimer->u.Std.ulNextJiffies = u64NextTS > u64NanoTS
852	? jiffies + rtTimerLnxNanoToJiffies(u64NextTS - u64NanoTS)
853	: jiffies;
854	spin_unlock_irqrestore(&pTimer->ChgIntLock, flFlags);
855
856	#ifdef CONFIG_SMP
857	if (pTimer->fSpecificCpu \|\| pTimer->fAllCpus)
858	mod_timer_pinned(&pSubTimer->u.Std.LnxTimer, pSubTimer->u.Std.ulNextJiffies);
859	else
860	#endif
861	mod_timer(&pSubTimer->u.Std.LnxTimer, pSubTimer->u.Std.ulNextJiffies);
862	return;
863	}
864	break;
865
866	default:
867	AssertMsgFailed(("%d\n", enmState));
868	return;
869	}
870	ASMNopPause();
871	}
872	}
873
874
875	#ifdef CONFIG_SMP
876
877	/**
878	* Per-cpu callback function (RTMpOnAll/RTMpOnSpecific).
879	*
880	* @param idCpu The current CPU.
881	* @param pvUser1 Pointer to the timer.
882	* @param pvUser2 Pointer to the argument structure.
883	*/
884	static DECLCALLBACK(void) rtTimerLnxStartAllOnCpu(RTCPUID idCpu, void pvUser1, void pvUser2)
885	{
886	PRTTIMERLINUXSTARTONCPUARGS pArgs = (PRTTIMERLINUXSTARTONCPUARGS)pvUser2;
887	PRTTIMER pTimer = (PRTTIMER)pvUser1;
888	Assert(idCpu < pTimer->cCpus);
889	rtTimerLnxStartSubTimer(&pTimer->aSubTimers[idCpu], pArgs->u64Now, pArgs->u64First, true /fPinned/, pTimer->fHighRes);
890	}
891
892
893	/**
894	* Worker for RTTimerStart() that takes care of the ugly bits.
895	*
896	* @returns RTTimerStart() return value.
897	* @param pTimer The timer.
898	* @param pArgs The argument structure.
899	*/
900	static int rtTimerLnxOmniStart(PRTTIMER pTimer, PRTTIMERLINUXSTARTONCPUARGS pArgs)
901	{
902	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
903	RTCPUID iCpu;
904	RTCPUSET OnlineSet;
905	RTCPUSET OnlineSet2;
906	int rc2;
907
908	/*
909	* Prepare all the sub-timers for the startup and then flag the timer
910	* as a whole as non-suspended, make sure we get them all before
911	* clearing fSuspended as the MP handler will be waiting on this
912	* should something happen while we're looping.
913	*/
914	RTSpinlockAcquire(pTimer->hSpinlock, &Tmp);
915
916	/* Just make it a omni timer restriction that no stop/start races are allowed. */
917	for (iCpu = 0; iCpu < pTimer->cCpus; iCpu++)
918	if (rtTimerLnxGetState(&pTimer->aSubTimers[iCpu].enmState) != RTTIMERLNXSTATE_STOPPED)
919	{
920	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
921	return VERR_TIMER_BUSY;
922	}
923
924	do
925	{
926	RTMpGetOnlineSet(&OnlineSet);
927	for (iCpu = 0; iCpu < pTimer->cCpus; iCpu++)
928	{
929	Assert(pTimer->aSubTimers[iCpu].enmState != RTTIMERLNXSTATE_MP_STOPPING);
930	rtTimerLnxSetState(&pTimer->aSubTimers[iCpu].enmState,
931	RTCpuSetIsMember(&OnlineSet, iCpu)
932	? RTTIMERLNXSTATE_STARTING
933	: RTTIMERLNXSTATE_STOPPED);
934	}
935	} while (!RTCpuSetIsEqual(&OnlineSet, RTMpGetOnlineSet(&OnlineSet2)));
936
937	ASMAtomicWriteBool(&pTimer->fSuspended, false);
938
939	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
940
941	/*
942	* Start them (can't find any exported function that allows me to
943	* do this without the cross calls).
944	*/
945	pArgs->u64Now = RTTimeSystemNanoTS();
946	rc2 = RTMpOnAll(rtTimerLnxStartAllOnCpu, pTimer, pArgs);
947	AssertRC(rc2); /* screw this if it fails. */
948
949	/*
950	* Reset the sub-timers who didn't start up (ALL CPUs case).
951	*/
952	RTSpinlockAcquire(pTimer->hSpinlock, &Tmp);
953
954	for (iCpu = 0; iCpu < pTimer->cCpus; iCpu++)
955	if (rtTimerLnxCmpXchgState(&pTimer->aSubTimers[iCpu].enmState, RTTIMERLNXSTATE_STOPPED, RTTIMERLNXSTATE_STARTING))
956	{
957	/** @todo very odd case for a rainy day. Cpus that temporarily went offline while
958	* we were between calls needs to nudged as the MP handler will ignore events for
959	* them because of the STARTING state. This is an extremely unlikely case - not that
960	* that means anything in my experience... ;-) */
961	RTTIMERLNX_LOG(("what!? iCpu=%u -> didn't start\n", iCpu));
962	}
963
964	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
965
966	return VINF_SUCCESS;
967	}
968
969
970	/**
971	* Worker for RTTimerStop() that takes care of the ugly SMP bits.
972	*
973	* @returns true if there was any active callbacks, false if not.
974	* @param pTimer The timer (valid).
975	* @param fForDestroy Whether this is for RTTimerDestroy or not.
976	*/
977	static bool rtTimerLnxOmniStop(PRTTIMER pTimer, bool fForDestroy)
978	{
979	bool fActiveCallbacks = false;
980	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
981	RTCPUID iCpu;
982	RTTIMERLNXSTATE enmState;
983
984
985	/*
986	* Mark the timer as suspended and flag all timers as stopping, except
987	* for those being stopped by an MP event.
988	*/
989	RTSpinlockAcquire(pTimer->hSpinlock, &Tmp);
990
991	ASMAtomicWriteBool(&pTimer->fSuspended, true);
992	for (iCpu = 0; iCpu < pTimer->cCpus; iCpu++)
993	{
994	for (;;)
995	{
996	enmState = rtTimerLnxGetState(&pTimer->aSubTimers[iCpu].enmState);
997	if ( enmState == RTTIMERLNXSTATE_STOPPED
998	\|\| enmState == RTTIMERLNXSTATE_MP_STOPPING)
999	break;
1000	if ( enmState == RTTIMERLNXSTATE_CALLBACK
1001	\|\| enmState == RTTIMERLNXSTATE_CB_STOPPING
1002	\|\| enmState == RTTIMERLNXSTATE_CB_RESTARTING)
1003	{
1004	Assert(enmState != RTTIMERLNXSTATE_CB_STOPPING \|\| fForDestroy);
1005	if (rtTimerLnxCmpXchgState(&pTimer->aSubTimers[iCpu].enmState,
1006	!fForDestroy ? RTTIMERLNXSTATE_CB_STOPPING : RTTIMERLNXSTATE_CB_DESTROYING,
1007	enmState))
1008	{
1009	fActiveCallbacks = true;
1010	break;
1011	}
1012	}
1013	else
1014	{
1015	Assert(enmState == RTTIMERLNXSTATE_ACTIVE);
1016	if (rtTimerLnxCmpXchgState(&pTimer->aSubTimers[iCpu].enmState, RTTIMERLNXSTATE_STOPPING, enmState))
1017	break;
1018	}
1019	ASMNopPause();
1020	}
1021	}
1022
1023	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
1024
1025	/*
1026	* Do the actual stopping. Fortunately, this doesn't require any IPIs.
1027	* Unfortunately it cannot be done synchronously.
1028	*/
1029	for (iCpu = 0; iCpu < pTimer->cCpus; iCpu++)
1030	if (rtTimerLnxGetState(&pTimer->aSubTimers[iCpu].enmState) == RTTIMERLNXSTATE_STOPPING)
1031	rtTimerLnxStopSubTimer(&pTimer->aSubTimers[iCpu], pTimer->fHighRes);
1032
1033	return fActiveCallbacks;
1034	}
1035
1036
1037	/**
1038	* Per-cpu callback function (RTMpOnSpecific) used by rtTimerLinuxMpEvent()
1039	* to start a sub-timer on a cpu that just have come online.
1040	*
1041	* @param idCpu The current CPU.
1042	* @param pvUser1 Pointer to the timer.
1043	* @param pvUser2 Pointer to the argument structure.
1044	*/
1045	static DECLCALLBACK(void) rtTimerLinuxMpStartOnCpu(RTCPUID idCpu, void pvUser1, void pvUser2)
1046	{
1047	PRTTIMERLINUXSTARTONCPUARGS pArgs = (PRTTIMERLINUXSTARTONCPUARGS)pvUser2;
1048	PRTTIMER pTimer = (PRTTIMER)pvUser1;
1049	RTSPINLOCK hSpinlock;
1050	Assert(idCpu < pTimer->cCpus);
1051
1052	/*
1053	* We have to be kind of careful here as we might be racing RTTimerStop
1054	* (and/or RTTimerDestroy, thus the paranoia.
1055	*/
1056	hSpinlock = pTimer->hSpinlock;
1057	if ( hSpinlock != NIL_RTSPINLOCK
1058	&& pTimer->u32Magic == RTTIMER_MAGIC)
1059	{
1060	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
1061	RTSpinlockAcquire(hSpinlock, &Tmp);
1062
1063	if ( !ASMAtomicUoReadBool(&pTimer->fSuspended)
1064	&& pTimer->u32Magic == RTTIMER_MAGIC)
1065	{
1066	/* We're sane and the timer is not suspended yet. */
1067	PRTTIMERLNXSUBTIMER pSubTimer = &pTimer->aSubTimers[idCpu];
1068	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_MP_STARTING, RTTIMERLNXSTATE_STOPPED))
1069	rtTimerLnxStartSubTimer(pSubTimer, pArgs->u64Now, pArgs->u64First, true /fPinned/, pTimer->fHighRes);
1070	}
1071
1072	RTSpinlockRelease(hSpinlock, &Tmp);
1073	}
1074	}
1075
1076
1077	/**
1078	* MP event notification callback.
1079	*
1080	* @param enmEvent The event.
1081	* @param idCpu The cpu it applies to.
1082	* @param pvUser The timer.
1083	*/
1084	static DECLCALLBACK(void) rtTimerLinuxMpEvent(RTMPEVENT enmEvent, RTCPUID idCpu, void *pvUser)
1085	{
1086	PRTTIMER pTimer = (PRTTIMER)pvUser;
1087	PRTTIMERLNXSUBTIMER pSubTimer = &pTimer->aSubTimers[idCpu];
1088	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
1089	RTSPINLOCK hSpinlock;
1090
1091	Assert(idCpu < pTimer->cCpus);
1092
1093	/*
1094	* Some initial paranoia.
1095	*/
1096	if (pTimer->u32Magic != RTTIMER_MAGIC)
1097	return;
1098	hSpinlock = pTimer->hSpinlock;
1099	if (hSpinlock == NIL_RTSPINLOCK)
1100	return;
1101
1102	RTSpinlockAcquire(hSpinlock, &Tmp);
1103
1104	/* Is it active? */
1105	if ( !ASMAtomicUoReadBool(&pTimer->fSuspended)
1106	&& pTimer->u32Magic == RTTIMER_MAGIC)
1107	{
1108	switch (enmEvent)
1109	{
1110	/*
1111	* Try do it without leaving the spin lock, but if we have to, retake it
1112	* when we're on the right cpu.
1113	*/
1114	case RTMPEVENT_ONLINE:
1115	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_MP_STARTING, RTTIMERLNXSTATE_STOPPED))
1116	{
1117	RTTIMERLINUXSTARTONCPUARGS Args;
1118	Args.u64Now = RTTimeSystemNanoTS();
1119	Args.u64First = 0;
1120
1121	if (RTMpCpuId() == idCpu)
1122	rtTimerLnxStartSubTimer(pSubTimer, Args.u64Now, Args.u64First, true /fPinned/, pTimer->fHighRes);
1123	else
1124	{
1125	rtTimerLnxSetState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED); /* we'll recheck it. */
1126	RTSpinlockRelease(hSpinlock, &Tmp);
1127
1128	RTMpOnSpecific(idCpu, rtTimerLinuxMpStartOnCpu, pTimer, &Args);
1129	return; /* we've left the spinlock */
1130	}
1131	}
1132	break;
1133
1134	/*
1135	* The CPU is (going) offline, make sure the sub-timer is stopped.
1136	*
1137	* Linux will migrate it to a different CPU, but we don't want this. The
1138	* timer function is checking for this.
1139	*/
1140	case RTMPEVENT_OFFLINE:
1141	{
1142	RTTIMERLNXSTATE enmState;
1143	while ( (enmState = rtTimerLnxGetState(&pSubTimer->enmState)) == RTTIMERLNXSTATE_ACTIVE
1144	\|\| enmState == RTTIMERLNXSTATE_CALLBACK
1145	\|\| enmState == RTTIMERLNXSTATE_CB_RESTARTING)
1146	{
1147	if (enmState == RTTIMERLNXSTATE_ACTIVE)
1148	{
1149	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_MP_STOPPING, RTTIMERLNXSTATE_ACTIVE))
1150	{
1151	RTSpinlockRelease(hSpinlock, &Tmp);
1152
1153	rtTimerLnxStopSubTimer(pSubTimer, pTimer->fHighRes);
1154	return; /* we've left the spinlock */
1155	}
1156	}
1157	else if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_CB_STOPPING, enmState))
1158	break;
1159
1160	/* State not stable, try again. */
1161	ASMNopPause();
1162	}
1163	break;
1164	}
1165	}
1166	}
1167
1168	RTSpinlockRelease(hSpinlock, &Tmp);
1169	}
1170
1171	#endif /* CONFIG_SMP */
1172
1173
1174	/**
1175	* Callback function use by RTTimerStart via RTMpOnSpecific to start a timer
1176	* running on a specific CPU.
1177	*
1178	* @param idCpu The current CPU.
1179	* @param pvUser1 Pointer to the timer.
1180	* @param pvUser2 Pointer to the argument structure.
1181	*/
1182	static DECLCALLBACK(void) rtTimerLnxStartOnSpecificCpu(RTCPUID idCpu, void pvUser1, void pvUser2)
1183	{
1184	PRTTIMERLINUXSTARTONCPUARGS pArgs = (PRTTIMERLINUXSTARTONCPUARGS)pvUser2;
1185	PRTTIMER pTimer = (PRTTIMER)pvUser1;
1186	rtTimerLnxStartSubTimer(&pTimer->aSubTimers[0], pArgs->u64Now, pArgs->u64First, true /fPinned/, pTimer->fHighRes);
1187	}
1188
1189
1190	RTDECL(int) RTTimerStart(PRTTIMER pTimer, uint64_t u64First)
1191	{
1192	RTTIMERLINUXSTARTONCPUARGS Args;
1193	int rc2;
1194
1195	/*
1196	* Validate.
1197	*/
1198	AssertPtrReturn(pTimer, VERR_INVALID_HANDLE);
1199	AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_HANDLE);
1200
1201	if (!ASMAtomicUoReadBool(&pTimer->fSuspended))
1202	return VERR_TIMER_ACTIVE;
1203	RTTIMERLNX_LOG(("start %p cCpus=%d\n", pTimer, pTimer->cCpus));
1204
1205	Args.u64First = u64First;
1206	#ifdef CONFIG_SMP
1207	/*
1208	* Omni timer?
1209	*/
1210	if (pTimer->fAllCpus)
1211	return rtTimerLnxOmniStart(pTimer, &Args);
1212	#endif
1213
1214	/*
1215	* Simple timer - Pretty straight forward if it wasn't for restarting.
1216	*/
1217	Args.u64Now = RTTimeSystemNanoTS();
1218	ASMAtomicWriteU64(&pTimer->aSubTimers[0].uNsRestartAt, Args.u64Now + u64First);
1219	for (;;)
1220	{
1221	RTTIMERLNXSTATE enmState = rtTimerLnxGetState(&pTimer->aSubTimers[0].enmState);
1222	switch (enmState)
1223	{
1224	case RTTIMERLNXSTATE_STOPPED:
1225	if (rtTimerLnxCmpXchgState(&pTimer->aSubTimers[0].enmState, RTTIMERLNXSTATE_STARTING, RTTIMERLNXSTATE_STOPPED))
1226	{
1227	ASMAtomicWriteBool(&pTimer->fSuspended, false);
1228	if (!pTimer->fSpecificCpu)
1229	rtTimerLnxStartSubTimer(&pTimer->aSubTimers[0], Args.u64Now, Args.u64First,
1230	false /fPinned/, pTimer->fHighRes);
1231	else
1232	{
1233	rc2 = RTMpOnSpecific(pTimer->idCpu, rtTimerLnxStartOnSpecificCpu, pTimer, &Args);
1234	if (RT_FAILURE(rc2))
1235	{
1236	/* Suspend it, the cpu id is probably invalid or offline. */
1237	ASMAtomicWriteBool(&pTimer->fSuspended, true);
1238	rtTimerLnxSetState(&pTimer->aSubTimers[0].enmState, RTTIMERLNXSTATE_STOPPED);
1239	return rc2;
1240	}
1241	}
1242	return VINF_SUCCESS;
1243	}
1244	break;
1245
1246	case RTTIMERLNXSTATE_CALLBACK:
1247	case RTTIMERLNXSTATE_CB_STOPPING:
1248	if (rtTimerLnxCmpXchgState(&pTimer->aSubTimers[0].enmState, RTTIMERLNXSTATE_CB_RESTARTING, enmState))
1249	{
1250	ASMAtomicWriteBool(&pTimer->fSuspended, false);
1251	return VINF_SUCCESS;
1252	}
1253	break;
1254
1255	default:
1256	AssertMsgFailed(("%d\n", enmState));
1257	return VERR_INTERNAL_ERROR_4;
1258	}
1259	ASMNopPause();
1260	}
1261	}
1262	RT_EXPORT_SYMBOL(RTTimerStart);
1263
1264
1265	/**
1266	* Common worker for RTTimerStop and RTTimerDestroy.
1267	*
1268	* @returns true if there was any active callbacks, false if not.
1269	* @param pTimer The timer to stop.
1270	* @param fForDestroy Whether it's RTTimerDestroy calling or not.
1271	*/
1272	static bool rtTimerLnxStop(PRTTIMER pTimer, bool fForDestroy)
1273	{
1274	RTTIMERLNX_LOG(("lnxstop %p %d\n", pTimer, fForDestroy));
1275	#ifdef CONFIG_SMP
1276	/*
1277	* Omni timer?
1278	*/
1279	if (pTimer->fAllCpus)
1280	return rtTimerLnxOmniStop(pTimer, fForDestroy);
1281	#endif
1282
1283	/*
1284	* Simple timer.
1285	*/
1286	ASMAtomicWriteBool(&pTimer->fSuspended, true);
1287	for (;;)
1288	{
1289	RTTIMERLNXSTATE enmState = rtTimerLnxGetState(&pTimer->aSubTimers[0].enmState);
1290	switch (enmState)
1291	{
1292	case RTTIMERLNXSTATE_ACTIVE:
1293	if (rtTimerLnxCmpXchgState(&pTimer->aSubTimers[0].enmState, RTTIMERLNXSTATE_STOPPING, RTTIMERLNXSTATE_ACTIVE))
1294	{
1295	rtTimerLnxStopSubTimer(&pTimer->aSubTimers[0], pTimer->fHighRes);
1296	return false;
1297	}
1298	break;
1299
1300	case RTTIMERLNXSTATE_CALLBACK:
1301	case RTTIMERLNXSTATE_CB_RESTARTING:
1302	case RTTIMERLNXSTATE_CB_STOPPING:
1303	Assert(enmState != RTTIMERLNXSTATE_CB_STOPPING \|\| fForDestroy);
1304	if (rtTimerLnxCmpXchgState(&pTimer->aSubTimers[0].enmState,
1305	!fForDestroy ? RTTIMERLNXSTATE_CB_STOPPING : RTTIMERLNXSTATE_CB_DESTROYING,
1306	enmState))
1307	return true;
1308	break;
1309
1310	case RTTIMERLNXSTATE_STOPPED:
1311	return VINF_SUCCESS;
1312
1313	case RTTIMERLNXSTATE_CB_DESTROYING:
1314	AssertMsgFailed(("enmState=%d pTimer=%p\n", enmState, pTimer));
1315	return true;
1316
1317	default:
1318	case RTTIMERLNXSTATE_STARTING:
1319	case RTTIMERLNXSTATE_MP_STARTING:
1320	case RTTIMERLNXSTATE_STOPPING:
1321	case RTTIMERLNXSTATE_MP_STOPPING:
1322	AssertMsgFailed(("enmState=%d pTimer=%p\n", enmState, pTimer));
1323	return false;
1324	}
1325
1326	/* State not stable, try again. */
1327	ASMNopPause();
1328	}
1329	}
1330
1331
1332	RTDECL(int) RTTimerStop(PRTTIMER pTimer)
1333	{
1334	/*
1335	* Validate.
1336	*/
1337	AssertPtrReturn(pTimer, VERR_INVALID_HANDLE);
1338	AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_HANDLE);
1339	RTTIMERLNX_LOG(("stop %p\n", pTimer));
1340
1341	if (ASMAtomicUoReadBool(&pTimer->fSuspended))
1342	return VERR_TIMER_SUSPENDED;
1343
1344	rtTimerLnxStop(pTimer, false /fForDestroy/);
1345	return VINF_SUCCESS;
1346	}
1347	RT_EXPORT_SYMBOL(RTTimerStop);
1348
1349
1350	RTDECL(int) RTTimerChangeInterval(PRTTIMER pTimer, uint64_t u64NanoInterval)
1351	{
1352	unsigned long cJiffies;
1353	unsigned long flFlags;
1354
1355	/*
1356	* Validate.
1357	*/
1358	AssertPtrReturn(pTimer, VERR_INVALID_HANDLE);
1359	AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_HANDLE);
1360	AssertReturn(u64NanoInterval, VERR_INVALID_PARAMETER);
1361	RTTIMERLNX_LOG(("change %p %llu\n", pTimer, u64NanoInterval));
1362
1363	#ifdef RTTIMER_LINUX_WITH_HRTIMER
1364	/*
1365	* For the high resolution timers it is easy since we don't care so much
1366	* about when it is applied to the sub-timers.
1367	*/
1368	if (pTimer->fHighRes)
1369	{
1370	ASMAtomicWriteU64(&pTimer->u64NanoInterval, u64NanoInterval);
1371	return VINF_SUCCESS;
1372	}
1373	#endif
1374
1375	/*
1376	* Standard timers have a bit more complicated way of calculating
1377	* their interval and such. So, forget omni timers for now.
1378	*/
1379	if (pTimer->cCpus > 1)
1380	return VERR_NOT_SUPPORTED;
1381
1382	cJiffies = u64NanoInterval / RTTimerGetSystemGranularity();
1383	if (cJiffies * RTTimerGetSystemGranularity() != u64NanoInterval)
1384	cJiffies = 0;
1385
1386	spin_lock_irqsave(&pTimer->ChgIntLock, flFlags);
1387	pTimer->aSubTimers[0].u.Std.fFirstAfterChg = true;
1388	pTimer->cJiffies = cJiffies;
1389	ASMAtomicWriteU64(&pTimer->u64NanoInterval, u64NanoInterval);
1390	spin_unlock_irqrestore(&pTimer->ChgIntLock, flFlags);
1391	return VINF_SUCCESS;
1392	}
1393	RT_EXPORT_SYMBOL(RTTimerChangeInterval);
1394
1395
1396	RTDECL(int) RTTimerDestroy(PRTTIMER pTimer)
1397	{
1398	bool fCanDestroy;
1399
1400	/*
1401	* Validate. It's ok to pass NULL pointer.
1402	*/
1403	if (pTimer == /NIL_RTTIMER/ NULL)
1404	return VINF_SUCCESS;
1405	AssertPtrReturn(pTimer, VERR_INVALID_HANDLE);
1406	AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_HANDLE);
1407	RTTIMERLNX_LOG(("destroy %p\n", pTimer));
1408	/** @todo We should invalidate the magic here! */
1409
1410	/*
1411	* Stop the timer if it's still active, then destroy it if we can.
1412	*/
1413	if (!ASMAtomicUoReadBool(&pTimer->fSuspended))
1414	fCanDestroy = rtTimerLnxStop(pTimer, true /fForDestroy/);
1415	else
1416	{
1417	uint32_t iCpu = pTimer->cCpus;
1418	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
1419	if (pTimer->cCpus > 1)
1420	RTSpinlockAcquireNoInts(pTimer->hSpinlock, &Tmp);
1421
1422	fCanDestroy = true;
1423	while (iCpu-- > 0)
1424	{
1425	for (;;)
1426	{
1427	RTTIMERLNXSTATE enmState = rtTimerLnxGetState(&pTimer->aSubTimers[iCpu].enmState);
1428	switch (enmState)
1429	{
1430	case RTTIMERLNXSTATE_CALLBACK:
1431	case RTTIMERLNXSTATE_CB_RESTARTING:
1432	case RTTIMERLNXSTATE_CB_STOPPING:
1433	if (!rtTimerLnxCmpXchgState(&pTimer->aSubTimers[iCpu].enmState, RTTIMERLNXSTATE_CB_DESTROYING, enmState))
1434	continue;
1435	fCanDestroy = false;
1436	break;
1437
1438	case RTTIMERLNXSTATE_CB_DESTROYING:
1439	AssertMsgFailed(("%d\n", enmState));
1440	fCanDestroy = false;
1441	break;
1442	default:
1443	break;
1444	}
1445	break;
1446	}
1447	}
1448
1449	if (pTimer->cCpus > 1)
1450	RTSpinlockReleaseNoInts(pTimer->hSpinlock, &Tmp);
1451	}
1452
1453	if (fCanDestroy)
1454	{
1455	/* For paranoid reasons, defer actually destroying the semaphore when
1456	in atomic or interrupt context. */
1457	#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 32)
1458	if (in_atomic() \|\| in_interrupt())
1459	#else
1460	if (in_interrupt())
1461	#endif
1462	rtR0LnxWorkqueuePush(&pTimer->DtorWorkqueueItem, rtTimerLnxDestroyDeferred);
1463	else
1464	rtTimerLnxDestroyIt(pTimer);
1465	}
1466
1467	return VINF_SUCCESS;
1468	}
1469	RT_EXPORT_SYMBOL(RTTimerDestroy);
1470
1471
1472	RTDECL(int) RTTimerCreateEx(PRTTIMER ppTimer, uint64_t u64NanoInterval, uint32_t fFlags, PFNRTTIMER pfnTimer, void pvUser)
1473	{
1474	PRTTIMER pTimer;
1475	RTCPUID iCpu;
1476	unsigned cCpus;
1477	int rc;
1478
1479	rtR0LnxWorkqueueFlush(); /* for 2.4 */
1480	*ppTimer = NULL;
1481
1482	/*
1483	* Validate flags.
1484	*/
1485	if (!RTTIMER_FLAGS_ARE_VALID(fFlags))
1486	return VERR_INVALID_PARAMETER;
1487	if ( (fFlags & RTTIMER_FLAGS_CPU_SPECIFIC)
1488	&& (fFlags & RTTIMER_FLAGS_CPU_ALL) != RTTIMER_FLAGS_CPU_ALL
1489	&& !RTMpIsCpuPossible(RTMpCpuIdFromSetIndex(fFlags & RTTIMER_FLAGS_CPU_MASK)))
1490	return VERR_CPU_NOT_FOUND;
1491
1492	/*
1493	* Allocate the timer handler.
1494	*/
1495	cCpus = 1;
1496	#ifdef CONFIG_SMP
1497	if ((fFlags & RTTIMER_FLAGS_CPU_ALL) == RTTIMER_FLAGS_CPU_ALL)
1498	{
1499	cCpus = RTMpGetMaxCpuId() + 1;
1500	Assert(cCpus <= RTCPUSET_MAX_CPUS); /* On linux we have a 1:1 relationship between cpuid and set index. */
1501	AssertReturn(u64NanoInterval, VERR_NOT_IMPLEMENTED); /* We don't implement single shot on all cpus, sorry. */
1502	}
1503	#endif
1504
1505	rc = RTMemAllocEx(RT_OFFSETOF(RTTIMER, aSubTimers[cCpus]), 0,
1506	RTMEMALLOCEX_FLAGS_ZEROED \| RTMEMALLOCEX_FLAGS_ANY_CTX_FREE, (void **)&pTimer);
1507	if (RT_FAILURE(rc))
1508	return rc;
1509
1510	/*
1511	* Initialize it.
1512	*/
1513	pTimer->u32Magic = RTTIMER_MAGIC;
1514	pTimer->hSpinlock = NIL_RTSPINLOCK;
1515	pTimer->fSuspended = true;
1516	pTimer->fHighRes = !!(fFlags & RTTIMER_FLAGS_HIGH_RES);
1517	#ifdef CONFIG_SMP
1518	pTimer->fSpecificCpu = (fFlags & RTTIMER_FLAGS_CPU_SPECIFIC) && (fFlags & RTTIMER_FLAGS_CPU_ALL) != RTTIMER_FLAGS_CPU_ALL;
1519	pTimer->fAllCpus = (fFlags & RTTIMER_FLAGS_CPU_ALL) == RTTIMER_FLAGS_CPU_ALL;
1520	pTimer->idCpu = pTimer->fSpecificCpu
1521	? RTMpCpuIdFromSetIndex(fFlags & RTTIMER_FLAGS_CPU_MASK)
1522	: NIL_RTCPUID;
1523	#else
1524	pTimer->fSpecificCpu = !!(fFlags & RTTIMER_FLAGS_CPU_SPECIFIC);
1525	pTimer->idCpu = RTMpCpuId();
1526	#endif
1527	pTimer->cCpus = cCpus;
1528	pTimer->pfnTimer = pfnTimer;
1529	pTimer->pvUser = pvUser;
1530	pTimer->u64NanoInterval = u64NanoInterval;
1531	pTimer->cJiffies = u64NanoInterval / RTTimerGetSystemGranularity();
1532	if (pTimer->cJiffies * RTTimerGetSystemGranularity() != u64NanoInterval)
1533	pTimer->cJiffies = 0;
1534	spin_lock_init(&pTimer->ChgIntLock);
1535
1536	for (iCpu = 0; iCpu < cCpus; iCpu++)
1537	{
1538	#ifdef RTTIMER_LINUX_WITH_HRTIMER
1539	if (pTimer->fHighRes)
1540	{
1541	hrtimer_init(&pTimer->aSubTimers[iCpu].u.Hr.LnxTimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1542	pTimer->aSubTimers[iCpu].u.Hr.LnxTimer.function = rtTimerLinuxHrCallback;
1543	}
1544	else
1545	#endif
1546	{
1547	init_timer(&pTimer->aSubTimers[iCpu].u.Std.LnxTimer);
1548	pTimer->aSubTimers[iCpu].u.Std.LnxTimer.data = (unsigned long)&pTimer->aSubTimers[iCpu];
1549	pTimer->aSubTimers[iCpu].u.Std.LnxTimer.function = rtTimerLinuxStdCallback;
1550	pTimer->aSubTimers[iCpu].u.Std.LnxTimer.expires = jiffies;
1551	pTimer->aSubTimers[iCpu].u.Std.u64NextTS = 0;
1552	}
1553	pTimer->aSubTimers[iCpu].iTick = 0;
1554	pTimer->aSubTimers[iCpu].pParent = pTimer;
1555	pTimer->aSubTimers[iCpu].enmState = RTTIMERLNXSTATE_STOPPED;
1556	}
1557
1558	#ifdef CONFIG_SMP
1559	/*
1560	* If this is running on ALL cpus, we'll have to register a callback
1561	* for MP events (so timers can be started/stopped on cpus going
1562	* online/offline). We also create the spinlock for synchronizing
1563	* stop/start/mp-event.
1564	*/
1565	if (cCpus > 1)
1566	{
1567	int rc = RTSpinlockCreate(&pTimer->hSpinlock);
1568	if (RT_SUCCESS(rc))
1569	rc = RTMpNotificationRegister(rtTimerLinuxMpEvent, pTimer);
1570	else
1571	pTimer->hSpinlock = NIL_RTSPINLOCK;
1572	if (RT_FAILURE(rc))
1573	{
1574	RTTimerDestroy(pTimer);
1575	return rc;
1576	}
1577	}
1578	#endif /* CONFIG_SMP */
1579
1580	RTTIMERLNX_LOG(("create %p hires=%d fFlags=%#x cCpus=%u\n", pTimer, pTimer->fHighRes, fFlags, cCpus));
1581	*ppTimer = pTimer;
1582	return VINF_SUCCESS;
1583	}
1584	RT_EXPORT_SYMBOL(RTTimerCreateEx);
1585
1586
1587	RTDECL(uint32_t) RTTimerGetSystemGranularity(void)
1588	{
1589	#if 0 /** @todo Not sure if this is what we want or not... Add new API for
1590	* querying the resolution of the high res timers? */
1591	struct timespec Ts;
1592	int rc = hrtimer_get_res(CLOCK_MONOTONIC, &Ts);
1593	if (!rc)
1594	{
1595	Assert(!Ts.tv_sec);
1596	return Ts.tv_nsec;
1597	}
1598	#endif
1599	return 1000000000 / HZ; /* ns */
1600	}
1601	RT_EXPORT_SYMBOL(RTTimerGetSystemGranularity);
1602
1603
1604	RTDECL(int) RTTimerRequestSystemGranularity(uint32_t u32Request, uint32_t *pu32Granted)
1605	{
1606	return VERR_NOT_SUPPORTED;
1607	}
1608	RT_EXPORT_SYMBOL(RTTimerRequestSystemGranularity);
1609
1610
1611	RTDECL(int) RTTimerReleaseSystemGranularity(uint32_t u32Granted)
1612	{
1613	return VERR_NOT_SUPPORTED;
1614	}
1615	RT_EXPORT_SYMBOL(RTTimerReleaseSystemGranularity);
1616
1617
1618	RTDECL(bool) RTTimerCanDoHighResolution(void)
1619	{
1620	#ifdef RTTIMER_LINUX_WITH_HRTIMER
1621	return true;
1622	#else
1623	return false;
1624	#endif
1625	}
1626	RT_EXPORT_SYMBOL(RTTimerCanDoHighResolution);
1627

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source: vbox/trunk/src/VBox/Runtime/r0drv/linux/timer-r0drv-linux.c@ 39008

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