threadctxhooks-r0drv-linux.c@ 69111

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1	/* $Id: threadctxhooks-r0drv-linux.c 69111 2017-10-17 14:26:02Z vboxsync $ */
2	/** @file
3	* IPRT - Thread Context Switching Hook, Ring-0 Driver, Linux.
4	*/
5
6	/*
7	* Copyright (C) 2013-2017 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/mem.h>
35	#include <iprt/assert.h>
36	#include <iprt/thread.h>
37	#include <iprt/err.h>
38	#include <iprt/asm.h>
39	#if defined(RT_ARCH_AMD64) \|\| defined(RT_ARCH_X86)
40	# include <iprt/asm-amd64-x86.h>
41	#endif
42	#include "internal/thread.h"
43
44
45	/*
46	* Linux kernel 2.6.23 introduced preemption notifiers but RedHat 2.6.18 kernels
47	* got it backported.
48	*/
49	#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 18) && defined(CONFIG_PREEMPT_NOTIFIERS)
50
51
52	/*********************************************************************************************************************************
53	* Structures and Typedefs *
54	*********************************************************************************************************************************/
55	/**
56	* The internal hook object for linux.
57	*/
58	typedef struct RTTHREADCTXHOOKINT
59	{
60	/** Magic value (RTTHREADCTXHOOKINT_MAGIC). */
61	uint32_t volatile u32Magic;
62	/** The thread handle (owner) for which the hook is registered. */
63	RTNATIVETHREAD hOwner;
64	/** The preemption notifier object. */
65	struct preempt_notifier LnxPreemptNotifier;
66	/** Whether the hook is enabled or not. If enabled, the LnxPreemptNotifier
67	* is linked into the owning thread's list of preemption callouts. */
68	bool fEnabled;
69	/** Pointer to the user callback. */
70	PFNRTTHREADCTXHOOK pfnCallback;
71	/** User argument passed to the callback. */
72	void *pvUser;
73	/** The linux callbacks. */
74	struct preempt_ops PreemptOps;
75	#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 1, 19) && defined(RT_ARCH_AMD64)
76	/** Starting with 3.1.19, the linux kernel doesn't restore kernel RFLAGS during
77	* task switch, so we have to do that ourselves. (x86 code is not affected.) */
78	RTCCUINTREG fSavedRFlags;
79	#endif
80	} RTTHREADCTXHOOKINT;
81	typedef RTTHREADCTXHOOKINT *PRTTHREADCTXHOOKINT;
82
83
84	/**
85	* Hook function for the thread schedule out event.
86	*
87	* @param pPreemptNotifier Pointer to the preempt_notifier struct.
88	* @param pNext Pointer to the task that is being scheduled
89	* instead of the current thread.
90	*
91	* @remarks Called with the rq (runqueue) lock held and with preemption and
92	* interrupts disabled!
93	*/
94	static void rtThreadCtxHooksLnxSchedOut(struct preempt_notifier pPreemptNotifier, struct task_struct pNext)
95	{
96	PRTTHREADCTXHOOKINT pThis = RT_FROM_MEMBER(pPreemptNotifier, RTTHREADCTXHOOKINT, LnxPreemptNotifier);
97	#if defined(RT_ARCH_AMD64) \|\| defined(RT_ARCH_X86)
98	RTCCUINTREG fSavedEFlags = ASMGetFlags();
99	stac();
100	#endif
101	RT_NOREF_PV(pNext);
102
103	AssertPtr(pThis);
104	AssertPtr(pThis->pfnCallback);
105	Assert(pThis->fEnabled);
106	Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
107
108	pThis->pfnCallback(RTTHREADCTXEVENT_OUT, pThis->pvUser);
109
110	#if defined(RT_ARCH_AMD64) \|\| defined(RT_ARCH_X86)
111	ASMSetFlags(fSavedEFlags);
112	# if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 1, 19) && defined(RT_ARCH_AMD64)
113	pThis->fSavedRFlags = fSavedEFlags;
114	# endif
115	#endif
116	}
117
118
119	/**
120	* Hook function for the thread schedule in event.
121	*
122	* @param pPreemptNotifier Pointer to the preempt_notifier struct.
123	* @param iCpu The CPU this thread is being scheduled on.
124	*
125	* @remarks Called without holding the rq (runqueue) lock and with preemption
126	* enabled!
127	* @todo r=bird: Preemption is of course disabled when it is called.
128	*/
129	static void rtThreadCtxHooksLnxSchedIn(struct preempt_notifier *pPreemptNotifier, int iCpu)
130	{
131	PRTTHREADCTXHOOKINT pThis = RT_FROM_MEMBER(pPreemptNotifier, RTTHREADCTXHOOKINT, LnxPreemptNotifier);
132	#if defined(RT_ARCH_AMD64) \|\| defined(RT_ARCH_X86)
133	RTCCUINTREG fSavedEFlags = ASMGetFlags();
134	stac();
135	#endif
136	RT_NOREF_PV(iCpu);
137
138	AssertPtr(pThis);
139	AssertPtr(pThis->pfnCallback);
140	Assert(pThis->fEnabled);
141
142	pThis->pfnCallback(RTTHREADCTXEVENT_IN, pThis->pvUser);
143
144	#if defined(RT_ARCH_AMD64) \|\| defined(RT_ARCH_X86)
145	# if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 1, 19) && defined(RT_ARCH_AMD64)
146	fSavedEFlags &= ~RT_BIT_64(18) /X86_EFL_AC/;
147	fSavedEFlags \|= pThis->fSavedRFlags & RT_BIT_64(18) /X86_EFL_AC/;
148	# endif
149	ASMSetFlags(fSavedEFlags);
150	#endif
151	}
152
153
154	/**
155	* Worker function for RTThreadCtxHooks(Deregister\|Release)().
156	*
157	* @param pThis Pointer to the internal thread-context object.
158	*/
159	DECLINLINE(void) rtThreadCtxHookDisable(PRTTHREADCTXHOOKINT pThis)
160	{
161	Assert(pThis->PreemptOps.sched_out == rtThreadCtxHooksLnxSchedOut);
162	Assert(pThis->PreemptOps.sched_in == rtThreadCtxHooksLnxSchedIn);
163	preempt_disable();
164	preempt_notifier_unregister(&pThis->LnxPreemptNotifier);
165	pThis->fEnabled = false;
166	preempt_enable();
167	}
168
169
170	RTDECL(int) RTThreadCtxHookCreate(PRTTHREADCTXHOOK phCtxHook, uint32_t fFlags, PFNRTTHREADCTXHOOK pfnCallback, void *pvUser)
171	{
172	IPRT_LINUX_SAVE_EFL_AC();
173
174	/*
175	* Validate input.
176	*/
177	PRTTHREADCTXHOOKINT pThis;
178	Assert(RTThreadPreemptIsEnabled(NIL_RTTHREAD));
179	AssertPtrReturn(pfnCallback, VERR_INVALID_POINTER);
180	AssertReturn(fFlags == 0, VERR_INVALID_FLAGS);
181
182	/*
183	* Allocate and initialize a new hook. We don't register it yet, just
184	* create it.
185	*/
186	pThis = (PRTTHREADCTXHOOKINT)RTMemAllocZ(sizeof(*pThis));
187	if (RT_UNLIKELY(!pThis))
188	{
189	IPRT_LINUX_RESTORE_EFL_AC();
190	return VERR_NO_MEMORY;
191	}
192	pThis->u32Magic = RTTHREADCTXHOOKINT_MAGIC;
193	pThis->hOwner = RTThreadNativeSelf();
194	pThis->fEnabled = false;
195	pThis->pfnCallback = pfnCallback;
196	pThis->pvUser = pvUser;
197	preempt_notifier_init(&pThis->LnxPreemptNotifier, &pThis->PreemptOps);
198	pThis->PreemptOps.sched_out = rtThreadCtxHooksLnxSchedOut;
199	pThis->PreemptOps.sched_in = rtThreadCtxHooksLnxSchedIn;
200
201	#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)
202	preempt_notifier_inc();
203	#endif
204
205	*phCtxHook = pThis;
206	IPRT_LINUX_RESTORE_EFL_AC();
207	return VINF_SUCCESS;
208	}
209	RT_EXPORT_SYMBOL(RTThreadCtxHookCreate);
210
211
212	RTDECL(int ) RTThreadCtxHookDestroy(RTTHREADCTXHOOK hCtxHook)
213	{
214	IPRT_LINUX_SAVE_EFL_AC();
215
216	/*
217	* Validate input.
218	*/
219	PRTTHREADCTXHOOKINT pThis = hCtxHook;
220	if (pThis == NIL_RTTHREADCTXHOOK)
221	return VINF_SUCCESS;
222	AssertPtr(pThis);
223	AssertMsgReturn(pThis->u32Magic == RTTHREADCTXHOOKINT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis),
224	VERR_INVALID_HANDLE);
225	Assert(RTThreadPreemptIsEnabled(NIL_RTTHREAD));
226	Assert(!pThis->fEnabled \|\| pThis->hOwner == RTThreadNativeSelf());
227
228	/*
229	* If there's still a registered thread-context hook, deregister it now before destroying the object.
230	*/
231	if (pThis->fEnabled)
232	{
233	Assert(pThis->hOwner == RTThreadNativeSelf());
234	rtThreadCtxHookDisable(pThis);
235	Assert(!pThis->fEnabled); /* paranoia */
236	}
237
238	#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)
239	preempt_notifier_dec();
240	#endif
241
242	ASMAtomicWriteU32(&pThis->u32Magic, ~RTTHREADCTXHOOKINT_MAGIC);
243	RTMemFree(pThis);
244
245	IPRT_LINUX_RESTORE_EFL_AC();
246	return VINF_SUCCESS;
247	}
248	RT_EXPORT_SYMBOL(RTThreadCtxHookDestroy);
249
250
251	RTDECL(int) RTThreadCtxHookEnable(RTTHREADCTXHOOK hCtxHook)
252	{
253	/*
254	* Validate input.
255	*/
256	PRTTHREADCTXHOOKINT pThis = hCtxHook;
257	AssertPtr(pThis);
258	AssertMsgReturn(pThis->u32Magic == RTTHREADCTXHOOKINT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis),
259	VERR_INVALID_HANDLE);
260	Assert(pThis->hOwner == RTThreadNativeSelf());
261	Assert(!pThis->fEnabled);
262	if (!pThis->fEnabled)
263	{
264	IPRT_LINUX_SAVE_EFL_AC();
265	Assert(pThis->PreemptOps.sched_out == rtThreadCtxHooksLnxSchedOut);
266	Assert(pThis->PreemptOps.sched_in == rtThreadCtxHooksLnxSchedIn);
267
268	/*
269	* Register the callback.
270	*/
271	preempt_disable();
272	pThis->fEnabled = true;
273	preempt_notifier_register(&pThis->LnxPreemptNotifier);
274	preempt_enable();
275
276	IPRT_LINUX_RESTORE_EFL_AC();
277	}
278
279	return VINF_SUCCESS;
280	}
281	RT_EXPORT_SYMBOL(RTThreadCtxHookEnable);
282
283
284	RTDECL(int) RTThreadCtxHookDisable(RTTHREADCTXHOOK hCtxHook)
285	{
286	/*
287	* Validate input.
288	*/
289	PRTTHREADCTXHOOKINT pThis = hCtxHook;
290	if (pThis != NIL_RTTHREADCTXHOOK)
291	{
292	AssertPtr(pThis);
293	AssertMsgReturn(pThis->u32Magic == RTTHREADCTXHOOKINT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis),
294	VERR_INVALID_HANDLE);
295	Assert(pThis->hOwner == RTThreadNativeSelf());
296
297	/*
298	* Deregister the callback.
299	*/
300	if (pThis->fEnabled)
301	{
302	IPRT_LINUX_SAVE_EFL_AC();
303	rtThreadCtxHookDisable(pThis);
304	IPRT_LINUX_RESTORE_EFL_AC();
305	}
306	}
307	return VINF_SUCCESS;
308	}
309	RT_EXPORT_SYMBOL(RTThreadCtxHookDisable);
310
311
312	RTDECL(bool) RTThreadCtxHookIsEnabled(RTTHREADCTXHOOK hCtxHook)
313	{
314	/*
315	* Validate input.
316	*/
317	PRTTHREADCTXHOOKINT pThis = hCtxHook;
318	if (pThis == NIL_RTTHREADCTXHOOK)
319	return false;
320	AssertPtr(pThis);
321	AssertMsgReturn(pThis->u32Magic == RTTHREADCTXHOOKINT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis),
322	false);
323
324	return pThis->fEnabled;
325	}
326
327	#else /* Not supported / Not needed */
328	# include "../generic/threadctxhooks-r0drv-generic.cpp"
329	#endif /* Not supported / Not needed */
330

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source: vbox/trunk/src/VBox/Runtime/r0drv/linux/threadctxhooks-r0drv-linux.c@ 69111

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