timer-r0drv-linux.c@ 27198

Last change on this file since 27198 was 27198, checked in by vboxsync, 15 years ago
r0drv/linux/timer: be consistent, this is SMP only
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 30.5 KB

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1	/* $Id: timer-r0drv-linux.c 27198 2010-03-09 09:52:40Z vboxsync $ */
2	/** @file
3	* IPRT - Timers, Ring-0 Driver, Linux.
4	*/
5
6	/*
7	* Copyright (C) 2006-2008 Sun Microsystems, Inc.
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	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
27	* Clara, CA 95054 USA or visit http://www.sun.com if you need
28	* additional information or have any questions.
29	*/
30
31
32	/*******************************************************************************
33	* Header Files *
34	*******************************************************************************/
35	#include "the-linux-kernel.h"
36	#include "internal/iprt.h"
37
38	#include <iprt/timer.h>
39	#include <iprt/time.h>
40	#include <iprt/mp.h>
41	#include <iprt/cpuset.h>
42	#include <iprt/spinlock.h>
43	#include <iprt/err.h>
44	#include <iprt/asm.h>
45	#include <iprt/assert.h>
46	#include <iprt/alloc.h>
47
48	#include "internal/magics.h"
49
50	/* We use the API of Linux 2.6.28+ (hrtimer_add_expires_ns()) */
51	#if !defined(RT_USE_LINUX_HRTIMER) \
52	&& LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28) \
53	&& 0 /* currently disabled */
54	# define RT_USE_LINUX_HRTIMER
55	#endif
56
57	/* This check must match the ktime usage in rtTimeGetSystemNanoTS() / time-r0drv-linux.c. */
58	#if defined(RT_USE_LINUX_HRTIMER) \
59	&& LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 28)
60	# error "RT_USE_LINUX_HRTIMER requires 2.6.28 or later, sorry."
61	#endif
62
63	#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 31)
64	# define mod_timer_pinned mod_timer
65	#endif
66
67
68	/*******************************************************************************
69	* Structures and Typedefs *
70	*******************************************************************************/
71	/**
72	* Timer state machine.
73	*
74	* This is used to try handle the issues with MP events and
75	* timers that runs on all CPUs. It's relatively nasty :-/
76	*/
77	typedef enum RTTIMERLNXSTATE
78	{
79	/** Stopped. */
80	RTTIMERLNXSTATE_STOPPED = 0,
81	/** Transient state; next ACTIVE. */
82	RTTIMERLNXSTATE_STARTING,
83	/** Transient state; next ACTIVE. (not really necessary) */
84	RTTIMERLNXSTATE_MP_STARTING,
85	/** Active. */
86	RTTIMERLNXSTATE_ACTIVE,
87	/** Transient state; next STOPPED. */
88	RTTIMERLNXSTATE_STOPPING,
89	/** Transient state; next STOPPED. */
90	RTTIMERLNXSTATE_MP_STOPPING,
91	/** The usual 32-bit hack. */
92	RTTIMERLNXSTATE_32BIT_HACK = 0x7fffffff
93	} RTTIMERLNXSTATE;
94
95
96	/**
97	* A Linux sub-timer.
98	*/
99	typedef struct RTTIMERLNXSUBTIMER
100	{
101	/** The linux timer structure. */
102	#ifdef RT_USE_LINUX_HRTIMER
103	struct hrtimer LnxTimer;
104	#else
105	struct timer_list LnxTimer;
106	/** The start of the current run (ns).
107	* This is used to calculate when the timer ought to fire the next time. */
108	uint64_t u64StartTS;
109	/** The start of the current run (ns).
110	* This is used to calculate when the timer ought to fire the next time. */
111	uint64_t u64NextTS;
112	#endif
113	/** The current tick number (since u64StartTS). */
114	uint64_t iTick;
115	/** Pointer to the parent timer. */
116	PRTTIMER pParent;
117	#ifndef RT_USE_LINUX_HRTIMER
118	/** The u64NextTS in jiffies. */
119	unsigned long ulNextJiffies;
120	#endif
121	/** The current sub-timer state. */
122	RTTIMERLNXSTATE volatile enmState;
123	} RTTIMERLNXSUBTIMER;
124	/** Pointer to a linux sub-timer. */
125	typedef RTTIMERLNXSUBTIMER *PRTTIMERLNXSUBTIMER;
126	AssertCompileMemberOffset(RTTIMERLNXSUBTIMER, LnxTimer, 0);
127
128
129	/**
130	* The internal representation of an Linux timer handle.
131	*/
132	typedef struct RTTIMER
133	{
134	/** Magic.
135	* This is RTTIMER_MAGIC, but changes to something else before the timer
136	* is destroyed to indicate clearly that thread should exit. */
137	uint32_t volatile u32Magic;
138	/** Spinlock synchronizing the fSuspended and MP event handling.
139	* This is NIL_RTSPINLOCK if cCpus == 1. */
140	RTSPINLOCK hSpinlock;
141	/** Flag indicating that the timer is suspended. */
142	bool volatile fSuspended;
143	/** Whether the timer must run on one specific CPU or not. */
144	bool fSpecificCpu;
145	#ifdef CONFIG_SMP
146	/** Whether the timer must run on all CPUs or not. */
147	bool fAllCpus;
148	#endif /* else: All -> specific on non-SMP kernels */
149	/** The CPU it must run on if fSpecificCpu is set. */
150	RTCPUID idCpu;
151	/** The number of CPUs this timer should run on. */
152	RTCPUID cCpus;
153	/** Callback. */
154	PFNRTTIMER pfnTimer;
155	/** User argument. */
156	void *pvUser;
157	/** The timer interval. 0 if one-shot. */
158	uint64_t u64NanoInterval;
159	#ifndef RT_USE_LINUX_HRTIMER
160	/** This is set to the number of jiffies between ticks if the interval is
161	* an exact number of jiffies. */
162	unsigned long cJiffies;
163	#endif
164	/** Sub-timers.
165	* Normally there is just one, but for RTTIMER_FLAGS_CPU_ALL this will contain
166	* an entry for all possible cpus. In that case the index will be the same as
167	* for the RTCpuSet. */
168	RTTIMERLNXSUBTIMER aSubTimers[1];
169	} RTTIMER;
170
171
172	/**
173	* A rtTimerLinuxStartOnCpu and rtTimerLinuxStartOnCpu argument package.
174	*/
175	typedef struct RTTIMERLINUXSTARTONCPUARGS
176	{
177	/** The current time (RTTimeNanoTS). */
178	uint64_t u64Now;
179	/** When to start firing (delta). */
180	uint64_t u64First;
181	} RTTIMERLINUXSTARTONCPUARGS;
182	/** Pointer to a rtTimerLinuxStartOnCpu argument package. */
183	typedef RTTIMERLINUXSTARTONCPUARGS *PRTTIMERLINUXSTARTONCPUARGS;
184
185
186	/**
187	* Sets the state.
188	*/
189	DECLINLINE(void) rtTimerLnxSetState(RTTIMERLNXSTATE volatile *penmState, RTTIMERLNXSTATE enmNewState)
190	{
191	ASMAtomicWriteU32((uint32_t volatile *)penmState, enmNewState);
192	}
193
194
195	/**
196	* Sets the state if it has a certain value.
197	*
198	* @return true if xchg was done.
199	* @return false if xchg wasn't done.
200	*/
201	DECLINLINE(bool) rtTimerLnxCmpXchgState(RTTIMERLNXSTATE volatile *penmState, RTTIMERLNXSTATE enmNewState, RTTIMERLNXSTATE enmCurState)
202	{
203	return ASMAtomicCmpXchgU32((uint32_t volatile *)penmState, enmNewState, enmCurState);
204	}
205
206
207	/**
208	* Gets the state.
209	*/
210	DECLINLINE(RTTIMERLNXSTATE) rtTimerLnxGetState(RTTIMERLNXSTATE volatile *penmState)
211	{
212	return (RTTIMERLNXSTATE)ASMAtomicUoReadU32((uint32_t volatile *)penmState);
213	}
214
215
216	#ifdef RT_USE_LINUX_HRTIMER
217	/**
218	* Converts a nano second time stamp to ktime_t.
219	*
220	* ASSUMES RTTimeNanoTS() is implemented using ktime_get_ts().
221	*
222	* @returns ktime_t.
223	* @param cNanoSecs Nanoseconds.
224	*/
225	DECLINLINE(ktime_t) rtTimerLnxNanoToKt(uint64_t cNanoSecs)
226	{
227	/* With some luck the compiler optimizes the division out of this... (Bet it doesn't.) */
228	return ktime_set(cNanoSecs / 1000000000, cNanoSecs % 1000000000);
229	}
230
231	/**
232	* Converts ktime_t to a nano second time stamp.
233	*
234	* ASSUMES RTTimeNanoTS() is implemented using ktime_get_ts().
235	*
236	* @returns nano second time stamp.
237	* @param Kt ktime_t.
238	*/
239	DECLINLINE(uint64_t) rtTimerLnxKtToNano(ktime_t Kt)
240	{
241	return ktime_to_ns(Kt);
242	}
243
244	#else /* ! RT_USE_LINUX_HRTIMER */
245
246	/**
247	* Converts a nano second interval to jiffies.
248	*
249	* @returns Jiffies.
250	* @param cNanoSecs Nanoseconds.
251	*/
252	DECLINLINE(unsigned long) rtTimerLnxNanoToJiffies(uint64_t cNanoSecs)
253	{
254	/* this can be made even better... */
255	if (cNanoSecs > (uint64_t)TICK_NSEC * MAX_JIFFY_OFFSET)
256	return MAX_JIFFY_OFFSET;
257	# if ARCH_BITS == 32
258	if (RT_LIKELY(cNanoSecs <= UINT32_MAX))
259	return ((uint32_t)cNanoSecs + (TICK_NSEC-1)) / TICK_NSEC;
260	# endif
261	return (cNanoSecs + (TICK_NSEC-1)) / TICK_NSEC;
262	}
263	#endif /* ! RT_USE_LINUX_HRTIMER */
264
265
266	/**
267	* Starts a sub-timer (RTTimerStart).
268	*
269	* @param pSubTimer The sub-timer to start.
270	* @param u64Now The current timestamp (RTTimeNanoTS()).
271	* @param u64First The interval from u64Now to the first time the timer should fire.
272	* @param fPinned true = timer pinned to a specific CPU,
273	* false = timer can migrate between CPUs
274	*/
275	static void rtTimerLnxStartSubTimer(PRTTIMERLNXSUBTIMER pSubTimer, uint64_t u64Now, uint64_t u64First, bool fPinned)
276	{
277	/*
278	* Calc when it should start firing.
279	*/
280	uint64_t u64NextTS = u64Now + u64First;
281	#ifndef RT_USE_LINUX_HRTIMER
282	pSubTimer->u64StartTS = u64NextTS;
283	pSubTimer->u64NextTS = u64NextTS;
284	#endif
285
286	pSubTimer->iTick = 0;
287
288	#ifdef RT_USE_LINUX_HRTIMER
289	hrtimer_start(&pSubTimer->LnxTimer, rtTimerLnxNanoToKt(u64NextTS), HRTIMER_MODE_ABS);
290	#else
291	{
292	unsigned long cJiffies = !u64First ? 0 : rtTimerLnxNanoToJiffies(u64First);
293	pSubTimer->ulNextJiffies = jiffies + cJiffies;
294	# ifdef CONFIG_SMP
295	if (fPinned)
296	mod_timer_pinned(&pSubTimer->LnxTimer, pSubTimer->ulNextJiffies);
297	else
298	# endif
299	mod_timer(&pSubTimer->LnxTimer, pSubTimer->ulNextJiffies);
300	}
301	#endif
302
303	rtTimerLnxSetState(&pSubTimer->enmState, RTTIMERLNXSTATE_ACTIVE);
304	}
305
306
307	/**
308	* Stops a sub-timer (RTTimerStart and rtTimerLinuxMpEvent()).
309	*
310	* @param pSubTimer The sub-timer.
311	*/
312	static void rtTimerLnxStopSubTimer(PRTTIMERLNXSUBTIMER pSubTimer)
313	{
314	#ifdef RT_USE_LINUX_HRTIMER
315	hrtimer_cancel(&pSubTimer->LnxTimer);
316	#else
317	if (timer_pending(&pSubTimer->LnxTimer))
318	del_timer_sync(&pSubTimer->LnxTimer);
319	#endif
320
321	rtTimerLnxSetState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED);
322	}
323
324
325	#ifdef RT_USE_LINUX_HRTIMER
326	/**
327	* Timer callback function.
328	* @returns HRTIMER_NORESTART or HRTIMER_RESTART depending on whether it's a one-shot or interval timer.
329	* @param pHrTimer Pointer to the sub-timer structure.
330	*/
331	static enum hrtimer_restart rtTimerLinuxCallback(struct hrtimer *pHrTimer)
332	#else
333	/**
334	* Timer callback function.
335	* @param ulUser Address of the sub-timer structure.
336	*/
337	static void rtTimerLinuxCallback(unsigned long ulUser)
338	#endif
339	{
340	#ifdef RT_USE_LINUX_HRTIMER
341	enum hrtimer_restart rc;
342	PRTTIMERLNXSUBTIMER pSubTimer = (PRTTIMERLNXSUBTIMER)pHrTimer;
343	#else
344	PRTTIMERLNXSUBTIMER pSubTimer = (PRTTIMERLNXSUBTIMER)ulUser;
345	#endif
346	PRTTIMER pTimer = pSubTimer->pParent;
347
348	/*
349	* Don't call the handler if the timer has been suspended.
350	* Also, when running on all CPUS, make sure we don't call out twice
351	* on a CPU because of timer migration.
352	*
353	* For the specific cpu case, we're just ignoring timer migration for now... (bad)
354	*/
355	if ( ASMAtomicUoReadBool(&pTimer->fSuspended)
356	#ifdef CONFIG_SMP
357	\|\| ( pTimer->fAllCpus
358	&& (RTCPUID)(pSubTimer - &pTimer->aSubTimers[0]) != RTMpCpuId())
359	#endif
360	)
361	{
362	rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED, RTTIMERLNXSTATE_ACTIVE);
363	# ifdef RT_USE_LINUX_HRTIMER
364	rc = HRTIMER_NORESTART;
365	# endif
366	}
367	else if (!pTimer->u64NanoInterval)
368	{
369	/*
370	* One shot timer, stop it before dispatching it.
371	*/
372	if (pTimer->cCpus == 1)
373	ASMAtomicWriteBool(&pTimer->fSuspended, true);
374	rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED, RTTIMERLNXSTATE_ACTIVE);
375	#ifdef RT_USE_LINUX_HRTIMER
376	rc = HRTIMER_NORESTART;
377	#else
378	/* detached before we're called, nothing to do for this case. */
379	#endif
380
381	pTimer->pfnTimer(pTimer, pTimer->pvUser, ++pSubTimer->iTick);
382	}
383	else
384	{
385	const uint64_t iTick = ++pSubTimer->iTick;
386
387	#ifdef RT_USE_LINUX_HRTIMER
388	hrtimer_add_expires_ns(&pSubTimer->LnxTimer, pTimer->u64NanoInterval);
389	rc = HRTIMER_RESTART;
390	#else
391	const uint64_t u64NanoTS = RTTimeNanoTS();
392
393	/*
394	* Interval timer, calculate the next timeout and re-arm it.
395	*
396	* The first time around, we'll re-adjust the u64StartTS to
397	* try prevent some jittering if we were started at a bad time.
398	* This may of course backfire with highres timers...
399	*/
400	if (RT_UNLIKELY(iTick == 1))
401	{
402	pSubTimer->u64StartTS = pSubTimer->u64NextTS = u64NanoTS;
403	pSubTimer->ulNextJiffies = jiffies;
404	}
405
406	pSubTimer->u64NextTS += pTimer->u64NanoInterval;
407	if (pTimer->cJiffies)
408	{
409	pSubTimer->ulNextJiffies += pTimer->cJiffies;
410	/* Prevent overflows when the jiffies counter wraps around.
411	* Special thanks to Ken Preslan for helping debugging! */
412	while (time_before(pSubTimer->ulNextJiffies, jiffies))
413	{
414	pSubTimer->ulNextJiffies += pTimer->cJiffies;
415	pSubTimer->u64NextTS += pTimer->u64NanoInterval;
416	}
417	}
418	else
419	{
420	while (pSubTimer->u64NextTS < u64NanoTS)
421	pSubTimer->u64NextTS += pTimer->u64NanoInterval;
422	pSubTimer->ulNextJiffies = jiffies + rtTimerLnxNanoToJiffies(pSubTimer->u64NextTS - u64NanoTS);
423	}
424
425	# ifdef CONFIG_SMP
426	if (pTimer->fSpecificCpu \|\| pTimer->fAllCpus)
427	mod_timer_pinned(&pSubTimer->LnxTimer, pSubTimer->ulNextJiffies);
428	else
429	# endif
430	mod_timer(&pSubTimer->LnxTimer, pSubTimer->ulNextJiffies);
431	#endif
432
433	/*
434	* Run the timer.
435	*/
436	pTimer->pfnTimer(pTimer, pTimer->pvUser, iTick);
437	}
438
439	#ifdef RT_USE_LINUX_HRTIMER
440	return rc;
441	#endif
442	}
443
444
445	#ifdef CONFIG_SMP
446
447	/**
448	* Per-cpu callback function (RTMpOnAll/RTMpOnSpecific).
449	*
450	* @param idCpu The current CPU.
451	* @param pvUser1 Pointer to the timer.
452	* @param pvUser2 Pointer to the argument structure.
453	*/
454	static DECLCALLBACK(void) rtTimerLnxStartAllOnCpu(RTCPUID idCpu, void pvUser1, void pvUser2)
455	{
456	PRTTIMERLINUXSTARTONCPUARGS pArgs = (PRTTIMERLINUXSTARTONCPUARGS)pvUser2;
457	PRTTIMER pTimer = (PRTTIMER)pvUser1;
458	Assert(idCpu < pTimer->cCpus);
459	rtTimerLnxStartSubTimer(&pTimer->aSubTimers[idCpu], pArgs->u64Now, pArgs->u64First, true /fPinned/);
460	}
461
462
463	/**
464	* Worker for RTTimerStart() that takes care of the ugly bit.s
465	*
466	* @returns RTTimerStart() return value.
467	* @param pTimer The timer.
468	* @param pArgs The argument structure.
469	*/
470	static int rtTimerLnxStartAll(PRTTIMER pTimer, PRTTIMERLINUXSTARTONCPUARGS pArgs)
471	{
472	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
473	RTCPUID iCpu;
474	RTCPUSET OnlineSet;
475	RTCPUSET OnlineSet2;
476	int rc2;
477
478	/*
479	* Prepare all the sub-timers for the startup and then flag the timer
480	* as a whole as non-suspended, make sure we get them all before
481	* clearing fSuspended as the MP handler will be waiting on this
482	* should something happen while we're looping.
483	*/
484	RTSpinlockAcquire(pTimer->hSpinlock, &Tmp);
485
486	do
487	{
488	RTMpGetOnlineSet(&OnlineSet);
489	for (iCpu = 0; iCpu < pTimer->cCpus; iCpu++)
490	{
491	Assert(pTimer->aSubTimers[iCpu].enmState != RTTIMERLNXSTATE_MP_STOPPING);
492	rtTimerLnxSetState(&pTimer->aSubTimers[iCpu].enmState,
493	RTCpuSetIsMember(&OnlineSet, iCpu)
494	? RTTIMERLNXSTATE_STARTING
495	: RTTIMERLNXSTATE_STOPPED);
496	}
497	} while (!RTCpuSetIsEqual(&OnlineSet, RTMpGetOnlineSet(&OnlineSet2)));
498
499	ASMAtomicWriteBool(&pTimer->fSuspended, false);
500
501	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
502
503	/*
504	* Start them (can't find any exported function that allows me to
505	* do this without the cross calls).
506	*/
507	pArgs->u64Now = RTTimeNanoTS();
508	rc2 = RTMpOnAll(rtTimerLnxStartAllOnCpu, pTimer, pArgs);
509	AssertRC(rc2); /* screw this if it fails. */
510
511	/*
512	* Reset the sub-timers who didn't start up (ALL CPUs case).
513	* CPUs that comes online between the
514	*/
515	RTSpinlockAcquire(pTimer->hSpinlock, &Tmp);
516
517	for (iCpu = 0; iCpu < pTimer->cCpus; iCpu++)
518	if (rtTimerLnxCmpXchgState(&pTimer->aSubTimers[iCpu].enmState, RTTIMERLNXSTATE_STOPPED, RTTIMERLNXSTATE_STARTING))
519	{
520	/** @todo very odd case for a rainy day. Cpus that temporarily went offline while
521	* we were between calls needs to nudged as the MP handler will ignore events for
522	* them because of the STARTING state. This is an extremely unlikely case - not that
523	* that means anything in my experience... ;-) */
524	}
525
526	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
527
528	return VINF_SUCCESS;
529	}
530
531
532	/**
533	* Worker for RTTimerStop() that takes care of the ugly SMP bits.
534	*
535	* @returns RTTimerStop() return value.
536	* @param pTimer The timer (valid).
537	*/
538	static int rtTimerLnxStopAll(PRTTIMER pTimer)
539	{
540	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
541	RTCPUID iCpu;
542
543
544	/*
545	* Mark the timer as suspended and flag all timers as stopping, except
546	* for those being stopped by an MP event.
547	*/
548	RTSpinlockAcquire(pTimer->hSpinlock, &Tmp);
549
550	ASMAtomicWriteBool(&pTimer->fSuspended, true);
551	for (iCpu = 0; iCpu < pTimer->cCpus; iCpu++)
552	{
553	RTTIMERLNXSTATE enmState;
554	do
555	{
556	enmState = rtTimerLnxGetState(&pTimer->aSubTimers[iCpu].enmState);
557	if ( enmState == RTTIMERLNXSTATE_STOPPED
558	\|\| enmState == RTTIMERLNXSTATE_MP_STOPPING)
559	break;
560	Assert(enmState == RTTIMERLNXSTATE_ACTIVE);
561	} while (!rtTimerLnxCmpXchgState(&pTimer->aSubTimers[iCpu].enmState, RTTIMERLNXSTATE_STOPPING, enmState));
562	}
563
564	RTSpinlockRelease(pTimer->hSpinlock, &Tmp);
565
566	/*
567	* Do the actual stopping. Fortunately, this doesn't require any IPIs.
568	* Unfortunately it cannot be done synchronously from within the spinlock,
569	* because we might end up in an active waiting for a handler to complete.
570	*/
571	for (iCpu = 0; iCpu < pTimer->cCpus; iCpu++)
572	if (rtTimerLnxGetState(&pTimer->aSubTimers[iCpu].enmState) == RTTIMERLNXSTATE_STOPPING)
573	rtTimerLnxStopSubTimer(&pTimer->aSubTimers[iCpu]);
574
575	return VINF_SUCCESS;
576	}
577
578
579	/**
580	* Per-cpu callback function (RTMpOnSpecific) used by rtTimerLinuxMpEvent()
581	* to start a sub-timer on a cpu that just have come online.
582	*
583	* @param idCpu The current CPU.
584	* @param pvUser1 Pointer to the timer.
585	* @param pvUser2 Pointer to the argument structure.
586	*/
587	static DECLCALLBACK(void) rtTimerLinuxMpStartOnCpu(RTCPUID idCpu, void pvUser1, void pvUser2)
588	{
589	PRTTIMERLINUXSTARTONCPUARGS pArgs = (PRTTIMERLINUXSTARTONCPUARGS)pvUser2;
590	PRTTIMER pTimer = (PRTTIMER)pvUser1;
591	RTSPINLOCK hSpinlock;
592	Assert(idCpu < pTimer->cCpus);
593
594	/*
595	* We have to be kind of careful here as we might be racing RTTimerStop
596	* (and/or RTTimerDestroy, thus the paranoia.
597	*/
598	hSpinlock = pTimer->hSpinlock;
599	if ( hSpinlock != NIL_RTSPINLOCK
600	&& pTimer->u32Magic == RTTIMER_MAGIC)
601	{
602	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
603	RTSpinlockAcquire(hSpinlock, &Tmp);
604
605	if ( !ASMAtomicUoReadBool(&pTimer->fSuspended)
606	&& pTimer->u32Magic == RTTIMER_MAGIC)
607	{
608	/* We're sane and the timer is not suspended yet. */
609	PRTTIMERLNXSUBTIMER pSubTimer = &pTimer->aSubTimers[idCpu];
610	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_MP_STARTING, RTTIMERLNXSTATE_STOPPED))
611	rtTimerLnxStartSubTimer(pSubTimer, pArgs->u64Now, pArgs->u64First, true /fPinned/);
612	}
613
614	RTSpinlockRelease(hSpinlock, &Tmp);
615	}
616	}
617
618
619	/**
620	* MP event notification callback.
621	*
622	* @param enmEvent The event.
623	* @param idCpu The cpu it applies to.
624	* @param pvUser The timer.
625	*/
626	static DECLCALLBACK(void) rtTimerLinuxMpEvent(RTMPEVENT enmEvent, RTCPUID idCpu, void *pvUser)
627	{
628	PRTTIMER pTimer = (PRTTIMER)pvUser;
629	PRTTIMERLNXSUBTIMER pSubTimer = &pTimer->aSubTimers[idCpu];
630	RTSPINLOCK hSpinlock;
631	RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
632
633	Assert(idCpu < pTimer->cCpus);
634
635	/*
636	* Some initial paranoia.
637	*/
638	if (pTimer->u32Magic != RTTIMER_MAGIC)
639	return;
640	hSpinlock = pTimer->hSpinlock;
641	if (hSpinlock == NIL_RTSPINLOCK)
642	return;
643
644	RTSpinlockAcquire(hSpinlock, &Tmp);
645
646	/* Is it active? */
647	if ( !ASMAtomicUoReadBool(&pTimer->fSuspended)
648	&& pTimer->u32Magic == RTTIMER_MAGIC)
649	{
650	switch (enmEvent)
651	{
652	/*
653	* Try do it without leaving the spin lock, but if we have to, retake it
654	* when we're on the right cpu.
655	*/
656	case RTMPEVENT_ONLINE:
657	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_MP_STARTING, RTTIMERLNXSTATE_STOPPED))
658	{
659	RTTIMERLINUXSTARTONCPUARGS Args;
660	Args.u64Now = RTTimeNanoTS();
661	Args.u64First = 0;
662
663	if (RTMpCpuId() == idCpu)
664	rtTimerLnxStartSubTimer(pSubTimer, Args.u64Now, Args.u64First, true /fPinned/);
665	else
666	{
667	rtTimerLnxSetState(&pSubTimer->enmState, RTTIMERLNXSTATE_STOPPED); /* we'll recheck it. */
668	RTSpinlockRelease(hSpinlock, &Tmp);
669
670	RTMpOnSpecific(idCpu, rtTimerLinuxMpStartOnCpu, pTimer, &Args);
671	return; /* we've left the spinlock */
672	}
673	}
674	break;
675
676	/*
677	* The CPU is (going) offline, make sure the sub-timer is stopped.
678	*
679	* Linux will migrate it to a different CPU, but we don't want this. The
680	* timer function is checking for this.
681	*/
682	case RTMPEVENT_OFFLINE:
683	if (rtTimerLnxCmpXchgState(&pSubTimer->enmState, RTTIMERLNXSTATE_MP_STOPPING, RTTIMERLNXSTATE_ACTIVE))
684	{
685	RTSpinlockRelease(hSpinlock, &Tmp);
686
687	rtTimerLnxStopSubTimer(pSubTimer);
688	return; /* we've left the spinlock */
689	}
690	break;
691	}
692	}
693
694	RTSpinlockRelease(hSpinlock, &Tmp);
695	}
696
697	#endif /* CONFIG_SMP */
698
699
700	/**
701	* Callback function use by RTTimerStart via RTMpOnSpecific to start
702	* a timer running on a specific CPU.
703	*
704	* @param idCpu The current CPU.
705	* @param pvUser1 Pointer to the timer.
706	* @param pvUser2 Pointer to the argument structure.
707	*/
708	static DECLCALLBACK(void) rtTimerLnxStartOnSpecificCpu(RTCPUID idCpu, void pvUser1, void pvUser2)
709	{
710	PRTTIMERLINUXSTARTONCPUARGS pArgs = (PRTTIMERLINUXSTARTONCPUARGS)pvUser2;
711	PRTTIMER pTimer = (PRTTIMER)pvUser1;
712	rtTimerLnxStartSubTimer(&pTimer->aSubTimers[0], pArgs->u64Now, pArgs->u64First, true /fPinned/);
713	}
714
715
716	RTDECL(int) RTTimerStart(PRTTIMER pTimer, uint64_t u64First)
717	{
718	RTTIMERLINUXSTARTONCPUARGS Args;
719	int rc2;
720
721	/*
722	* Validate.
723	*/
724	AssertPtrReturn(pTimer, VERR_INVALID_HANDLE);
725	AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_HANDLE);
726
727	if (!ASMAtomicUoReadBool(&pTimer->fSuspended))
728	return VERR_TIMER_ACTIVE;
729
730	Args.u64First = u64First;
731	#ifdef CONFIG_SMP
732	/*
733	* Omnit timer?
734	*/
735	if (pTimer->fAllCpus)
736	return rtTimerLnxStartAll(pTimer, &Args);
737	#endif
738
739	/*
740	* Simple timer - Pretty straight forward.
741	*/
742	Args.u64Now = RTTimeNanoTS();
743	rtTimerLnxSetState(&pTimer->aSubTimers[0].enmState, RTTIMERLNXSTATE_STARTING);
744	ASMAtomicWriteBool(&pTimer->fSuspended, false);
745	if (!pTimer->fSpecificCpu)
746	rtTimerLnxStartSubTimer(&pTimer->aSubTimers[0], Args.u64Now, Args.u64First, false /fPinned/);
747	else
748	{
749	rc2 = RTMpOnSpecific(pTimer->idCpu, rtTimerLnxStartOnSpecificCpu, pTimer, &Args);
750	if (RT_FAILURE(rc2))
751	{
752	/* Suspend it, the cpu id is probably invalid or offline. */
753	ASMAtomicWriteBool(&pTimer->fSuspended, true);
754	rtTimerLnxSetState(&pTimer->aSubTimers[0].enmState, RTTIMERLNXSTATE_STOPPED);
755	return rc2;
756	}
757	}
758
759	return VINF_SUCCESS;
760	}
761	RT_EXPORT_SYMBOL(RTTimerStart);
762
763
764	RTDECL(int) RTTimerStop(PRTTIMER pTimer)
765	{
766
767	/*
768	* Validate.
769	*/
770	AssertPtrReturn(pTimer, VERR_INVALID_HANDLE);
771	AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_HANDLE);
772
773	if (ASMAtomicUoReadBool(&pTimer->fSuspended))
774	return VERR_TIMER_SUSPENDED;
775
776	#ifdef CONFIG_SMP
777	/*
778	* Omni timer?
779	*/
780	if (pTimer->fAllCpus)
781	return rtTimerLnxStopAll(pTimer);
782	#endif
783
784	/*
785	* Simple timer.
786	*/
787	ASMAtomicWriteBool(&pTimer->fSuspended, true);
788	rtTimerLnxSetState(&pTimer->aSubTimers[0].enmState, RTTIMERLNXSTATE_STOPPING);
789	rtTimerLnxStopSubTimer(&pTimer->aSubTimers[0]);
790
791	return VINF_SUCCESS;
792	}
793	RT_EXPORT_SYMBOL(RTTimerStop);
794
795
796	RTDECL(int) RTTimerDestroy(PRTTIMER pTimer)
797	{
798	RTSPINLOCK hSpinlock;
799
800	/* It's ok to pass NULL pointer. */
801	if (pTimer == /NIL_RTTIMER/ NULL)
802	return VINF_SUCCESS;
803	AssertPtrReturn(pTimer, VERR_INVALID_HANDLE);
804	AssertReturn(pTimer->u32Magic == RTTIMER_MAGIC, VERR_INVALID_HANDLE);
805
806	/*
807	* Remove the MP notifications first because it'll reduce the risk of
808	* us overtaking any MP event that might theoretically be racing us here.
809	*/
810	hSpinlock = pTimer->hSpinlock;
811	#ifdef CONFIG_SMP
812	if ( pTimer->cCpus > 1
813	&& hSpinlock != NIL_RTSPINLOCK)
814	{
815	int rc = RTMpNotificationDeregister(rtTimerLinuxMpEvent, pTimer);
816	AssertRC(rc);
817	}
818	#endif /* CONFIG_SMP */
819
820	/*
821	* Stop the timer if it's running.
822	*/
823	if (!ASMAtomicUoReadBool(&pTimer->fSuspended))
824	RTTimerStop(pTimer);
825
826	/*
827	* Uninitialize the structure and free the associated resources.
828	* The spinlock goes last.
829	*/
830	ASMAtomicWriteU32(&pTimer->u32Magic, ~RTTIMER_MAGIC);
831	RTMemFree(pTimer);
832	if (hSpinlock != NIL_RTSPINLOCK)
833	RTSpinlockDestroy(hSpinlock);
834
835	return VINF_SUCCESS;
836	}
837	RT_EXPORT_SYMBOL(RTTimerDestroy);
838
839
840	RTDECL(int) RTTimerCreateEx(PRTTIMER ppTimer, uint64_t u64NanoInterval, unsigned fFlags, PFNRTTIMER pfnTimer, void pvUser)
841	{
842	PRTTIMER pTimer;
843	RTCPUID iCpu;
844	unsigned cCpus;
845
846	*ppTimer = NULL;
847
848	/*
849	* Validate flags.
850	*/
851	if (!RTTIMER_FLAGS_ARE_VALID(fFlags))
852	return VERR_INVALID_PARAMETER;
853	if ( (fFlags & RTTIMER_FLAGS_CPU_SPECIFIC)
854	&& (fFlags & RTTIMER_FLAGS_CPU_ALL) != RTTIMER_FLAGS_CPU_ALL
855	&& !RTMpIsCpuOnline(fFlags & RTTIMER_FLAGS_CPU_MASK))
856	return (fFlags & RTTIMER_FLAGS_CPU_MASK) > RTMpGetMaxCpuId()
857	? VERR_CPU_NOT_FOUND
858	: VERR_CPU_OFFLINE;
859
860	/*
861	* Allocate the timer handler.
862	*/
863	cCpus = 1;
864	#ifdef CONFIG_SMP
865	if ((fFlags & RTTIMER_FLAGS_CPU_ALL) == RTTIMER_FLAGS_CPU_ALL)
866	{
867	cCpus = RTMpGetMaxCpuId() + 1;
868	Assert(cCpus <= RTCPUSET_MAX_CPUS); /* On linux we have a 1:1 relationship between cpuid and set index. */
869	AssertReturn(u64NanoInterval, VERR_NOT_IMPLEMENTED); /* We don't implement single shot on all cpus, sorry. */
870	}
871	#endif
872
873	pTimer = (PRTTIMER)RTMemAllocZ(RT_OFFSETOF(RTTIMER, aSubTimers[cCpus]));
874	if (!pTimer)
875	return VERR_NO_MEMORY;
876
877	/*
878	* Initialize it.
879	*/
880	pTimer->u32Magic = RTTIMER_MAGIC;
881	pTimer->hSpinlock = NIL_RTSPINLOCK;
882	pTimer->fSuspended = true;
883	#ifdef CONFIG_SMP
884	pTimer->fSpecificCpu = (fFlags & RTTIMER_FLAGS_CPU_SPECIFIC) && (fFlags & RTTIMER_FLAGS_CPU_ALL) != RTTIMER_FLAGS_CPU_ALL;
885	pTimer->fAllCpus = (fFlags & RTTIMER_FLAGS_CPU_ALL) == RTTIMER_FLAGS_CPU_ALL;
886	pTimer->idCpu = fFlags & RTTIMER_FLAGS_CPU_MASK;
887	#else
888	pTimer->fSpecificCpu = !!(fFlags & RTTIMER_FLAGS_CPU_SPECIFIC);
889	pTimer->idCpu = RTMpCpuId();
890	#endif
891	pTimer->cCpus = cCpus;
892	pTimer->pfnTimer = pfnTimer;
893	pTimer->pvUser = pvUser;
894	pTimer->u64NanoInterval = u64NanoInterval;
895	#ifndef RT_USE_LINUX_HRTIMER
896	pTimer->cJiffies = u64NanoInterval / RTTimerGetSystemGranularity();
897	if (pTimer->cJiffies * RTTimerGetSystemGranularity() != u64NanoInterval)
898	pTimer->cJiffies = 0;
899	#endif
900
901	for (iCpu = 0; iCpu < cCpus; iCpu++)
902	{
903	#ifdef RT_USE_LINUX_HRTIMER
904	hrtimer_init(&pTimer->aSubTimers[iCpu].LnxTimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
905	pTimer->aSubTimers[iCpu].LnxTimer.function = rtTimerLinuxCallback;
906	#else
907	init_timer(&pTimer->aSubTimers[iCpu].LnxTimer);
908	pTimer->aSubTimers[iCpu].LnxTimer.data = (unsigned long)&pTimer->aSubTimers[iCpu];
909	pTimer->aSubTimers[iCpu].LnxTimer.function = rtTimerLinuxCallback;
910	pTimer->aSubTimers[iCpu].LnxTimer.expires = jiffies;
911	pTimer->aSubTimers[iCpu].u64StartTS = 0;
912	pTimer->aSubTimers[iCpu].u64NextTS = 0;
913	#endif
914	pTimer->aSubTimers[iCpu].iTick = 0;
915	pTimer->aSubTimers[iCpu].pParent = pTimer;
916	pTimer->aSubTimers[iCpu].enmState = RTTIMERLNXSTATE_STOPPED;
917	}
918
919	#ifdef CONFIG_SMP
920	/*
921	* If this is running on ALL cpus, we'll have to register a callback
922	* for MP events (so timers can be started/stopped on cpus going
923	* online/offline). We also create the spinlock for syncrhonizing
924	* stop/start/mp-event.
925	*/
926	if (cCpus > 1)
927	{
928	int rc = RTSpinlockCreate(&pTimer->hSpinlock);
929	if (RT_SUCCESS(rc))
930	rc = RTMpNotificationRegister(rtTimerLinuxMpEvent, pTimer);
931	else
932	pTimer->hSpinlock = NIL_RTSPINLOCK;
933	if (RT_FAILURE(rc))
934	{
935	RTTimerDestroy(pTimer);
936	return rc;
937	}
938	}
939	#endif /* CONFIG_SMP */
940
941	*ppTimer = pTimer;
942	return VINF_SUCCESS;
943	}
944	RT_EXPORT_SYMBOL(RTTimerCreateEx);
945
946
947	RTDECL(uint32_t) RTTimerGetSystemGranularity(void)
948	{
949	#ifdef RT_USE_LINUX_HRTIMER
950	struct timespec Ts;
951	int rc = hrtimer_get_res(CLOCK_MONOTONIC, &Ts);
952	if (!rc)
953	{
954	Assert(!Ts.tv_sec);
955	return Ts.tv_nsec;
956	}
957	#endif
958	return 1000000000 / HZ; /* ns */
959	}
960	RT_EXPORT_SYMBOL(RTTimerGetSystemGranularity);
961
962
963	RTDECL(int) RTTimerRequestSystemGranularity(uint32_t u32Request, uint32_t *pu32Granted)
964	{
965	return VERR_NOT_SUPPORTED;
966	}
967	RT_EXPORT_SYMBOL(RTTimerRequestSystemGranularity);
968
969
970	RTDECL(int) RTTimerReleaseSystemGranularity(uint32_t u32Granted)
971	{
972	return VERR_NOT_SUPPORTED;
973	}
974	RT_EXPORT_SYMBOL(RTTimerReleaseSystemGranularity);
975

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source: vbox/trunk/src/VBox/Runtime/r0drv/linux/timer-r0drv-linux.c@ 27198

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