VirtualBox

source: vbox/trunk/src/VBox/Runtime/r0drv/darwin/threadpreempt-r0drv-darwin.cpp@ 94293

Last change on this file since 94293 was 93115, checked in by vboxsync, 3 years ago

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1/* $Id: threadpreempt-r0drv-darwin.cpp 93115 2022-01-01 11:31:46Z vboxsync $ */
2/** @file
3 * IPRT - Thread Preemption, Ring-0 Driver, Darwin.
4 */
5
6/*
7 * Copyright (C) 2009-2022 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-darwin-kernel.h"
32#include "internal/iprt.h"
33#include <iprt/thread.h>
34
35#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
36# include <iprt/asm-amd64-x86.h>
37#endif
38#include <iprt/assert.h>
39#include <iprt/cpuset.h>
40#include <iprt/errcore.h>
41#include <iprt/mp.h>
42
43
44/*********************************************************************************************************************************
45* Structures and Typedefs *
46*********************************************************************************************************************************/
47typedef struct RTDARWINPREEMPTHACK
48{
49 /** The spinlock we exploit for disabling preemption. */
50 lck_spin_t *pSpinLock;
51 /** The preemption count for this CPU, to guard against nested calls. */
52 uint32_t cRecursion;
53} RTDARWINPREEMPTHACK;
54typedef RTDARWINPREEMPTHACK *PRTDARWINPREEMPTHACK;
55
56
57/*********************************************************************************************************************************
58* Global Variables *
59*********************************************************************************************************************************/
60static RTDARWINPREEMPTHACK g_aPreemptHacks[RTCPUSET_MAX_CPUS];
61
62
63/**
64 * Allocates the per-cpu spin locks used to disable preemption.
65 *
66 * Called by rtR0InitNative.
67 */
68int rtThreadPreemptDarwinInit(void)
69{
70 Assert(g_pDarwinLockGroup);
71 IPRT_DARWIN_SAVE_EFL_AC();
72
73 for (size_t i = 0; i < RT_ELEMENTS(g_aPreemptHacks); i++)
74 {
75 g_aPreemptHacks[i].pSpinLock = lck_spin_alloc_init(g_pDarwinLockGroup, LCK_ATTR_NULL);
76 if (!g_aPreemptHacks[i].pSpinLock)
77 return VERR_NO_MEMORY; /* (The caller will invoke rtThreadPreemptDarwinTerm) */
78 }
79 IPRT_DARWIN_RESTORE_EFL_AC();
80 return VINF_SUCCESS;
81}
82
83
84/**
85 * Frees the per-cpu spin locks used to disable preemption.
86 *
87 * Called by rtR0TermNative.
88 */
89void rtThreadPreemptDarwinTerm(void)
90{
91 IPRT_DARWIN_SAVE_EFL_AC();
92
93 for (size_t i = 0; i < RT_ELEMENTS(g_aPreemptHacks); i++)
94 if (g_aPreemptHacks[i].pSpinLock)
95 {
96 lck_spin_free(g_aPreemptHacks[i].pSpinLock, g_pDarwinLockGroup);
97 g_aPreemptHacks[i].pSpinLock = NULL;
98 }
99
100 IPRT_DARWIN_RESTORE_EFL_AC();
101}
102
103
104RTDECL(bool) RTThreadPreemptIsEnabled(RTTHREAD hThread)
105{
106 RT_NOREF(hThread);
107 Assert(hThread == NIL_RTTHREAD);
108 return preemption_enabled();
109}
110
111
112RTDECL(bool) RTThreadPreemptIsPending(RTTHREAD hThread)
113{
114 RT_NOREF(hThread);
115 if (!g_pfnR0DarwinAstPending)
116 return false;
117 uint32_t volatile *pfAstPending = g_pfnR0DarwinAstPending(); AssertPtr(pfAstPending);
118 uint32_t const fAstPending = *pfAstPending;
119
120 AssertMsg(!(fAstPending & UINT32_C(0xfffe0000)), ("%#x\n", fAstPending));
121 return (fAstPending & (AST_PREEMPT | AST_QUANTUM | AST_URGENT)) != 0;
122}
123
124
125RTDECL(bool) RTThreadPreemptIsPendingTrusty(void)
126{
127 /* yes, we think that RTThreadPreemptIsPending is reliable... */
128 return g_pfnR0DarwinAstPending != NULL;
129}
130
131
132RTDECL(bool) RTThreadPreemptIsPossible(void)
133{
134 /* yes, kernel preemption is possible. */
135 return true;
136}
137
138
139RTDECL(void) RTThreadPreemptDisable(PRTTHREADPREEMPTSTATE pState)
140{
141 AssertPtr(pState);
142 Assert(pState->u32Reserved == 0);
143 pState->u32Reserved = 42;
144
145 /*
146 * Disable to prevent preemption while we grab the per-cpu spin lock.
147 * Note! Only take the lock on the first call or we end up spinning for ever.
148 */
149 RTCCUINTREG fSavedFlags = ASMIntDisableFlags();
150 RTCPUID idCpu = RTMpCpuId();
151 if (RT_UNLIKELY(idCpu < RT_ELEMENTS(g_aPreemptHacks)))
152 {
153 Assert(g_aPreemptHacks[idCpu].cRecursion < UINT32_MAX / 2);
154 if (++g_aPreemptHacks[idCpu].cRecursion == 1)
155 {
156 lck_spin_t *pSpinLock = g_aPreemptHacks[idCpu].pSpinLock;
157 if (pSpinLock)
158 lck_spin_lock(pSpinLock);
159 else
160 AssertFailed();
161 }
162 }
163 ASMSetFlags(fSavedFlags);
164 Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
165 RT_ASSERT_PREEMPT_CPUID_DISABLE(pState);
166}
167
168
169RTDECL(void) RTThreadPreemptRestore(PRTTHREADPREEMPTSTATE pState)
170{
171 AssertPtr(pState);
172 Assert(pState->u32Reserved == 42);
173 pState->u32Reserved = 0;
174 RT_ASSERT_PREEMPT_CPUID_RESTORE(pState);
175
176 RTCPUID idCpu = RTMpCpuId();
177 if (RT_UNLIKELY(idCpu < RT_ELEMENTS(g_aPreemptHacks)))
178 {
179 Assert(g_aPreemptHacks[idCpu].cRecursion > 0);
180 if (--g_aPreemptHacks[idCpu].cRecursion == 0)
181 {
182 lck_spin_t *pSpinLock = g_aPreemptHacks[idCpu].pSpinLock;
183 if (pSpinLock)
184 {
185 IPRT_DARWIN_SAVE_EFL_AC();
186 lck_spin_unlock(pSpinLock);
187 IPRT_DARWIN_RESTORE_EFL_AC();
188 }
189 else
190 AssertFailed();
191 }
192 }
193}
194
195
196RTDECL(bool) RTThreadIsInInterrupt(RTTHREAD hThread)
197{
198 Assert(hThread == NIL_RTTHREAD); NOREF(hThread);
199 /** @todo Darwin: Implement RTThreadIsInInterrupt. Required for guest
200 * additions! */
201 return !ASMIntAreEnabled();
202}
203
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