1/*
2 * Copyright (c) 2000-2017 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28
29#ifndef _PTHREAD_PRIORITY_PRIVATE_H_
30#define _PTHREAD_PRIORITY_PRIVATE_H_
31
32/*!
33 * @typedef pthread_priority_t
34 *
35 * @abstract
36 * pthread_priority_t is an on opaque integer that is guaranteed to be ordered
37 * such that combations of QoS classes and relative priorities are ordered
38 * numerically, according to their combined priority.
39 *
40 * <b>xnu, pthread & libdispatch flags</b>
41 *
42 * @const _PTHREAD_PRIORITY_OVERCOMMIT_FLAG
43 * The thread this priority is applied to is overcommit (affects the workqueue
44 * creation policy for this priority).
45 *
46 * @const _PTHREAD_PRIORITY_FALLBACK_FLAG
47 * Indicates that this priority is is used only when incoming events have no
48 * priority at all. It is merely used as a fallback (hence the name) instead of
49 * a floor.
50 *
51 * This is usually used with QOS_CLASS_DEFAULT and a 0 relative priority.
52 *
53 * @const _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG
54 * The event manager flag indicates that this thread/request is for a event
55 * manager thread. There can only ever be one event manager thread at a time
56 * and it is brought up at the highest of all event manager priorities pthread
57 * knows about.
58 *
59 * <b>pthread & dispatch only flags</b>
60 *
61 * @const _PTHREAD_PRIORITY_SCHED_PRI_FLAG
62 * @const _PTHREAD_PRIORITY_SCHED_PRI_MASK
63 * This flag indicates that the bits extracted using
64 * _PTHREAD_PRIORITY_SCHED_PRI_MASK represent a scheduler priority instead of
65 * a {qos, relative priority} pair.
66 *
67 * This flag is only used by the pthread kext to indicate libdispatch that the
68 * event manager queue priority is a scheduling priority and not a QoS. This
69 * flag is never used as an input by anything else and is why it can perform
70 * a double duty with _PTHREAD_PRIORITY_ROOTQUEUE_FLAG.
71 *
72 * @const _PTHREAD_PRIORITY_NEEDS_UNBIND_FLAG
73 * This flag is used for the priority of event delivery threads to indicate
74 * to libdispatch that this thread is bound to a kqueue.
75 *
76 * <b>dispatch only flags</b>
77 *
78 * @const _PTHREAD_PRIORITY_INHERIT_FLAG
79 * This flag is meaningful to libdispatch only and has no meanting for the
80 * kernel and/or pthread.
81 *
82 * @const _PTHREAD_PRIORITY_ROOTQUEUE_FLAG
83 * This flag is meaningful to libdispatch only and has no meanting for the
84 * kernel and/or pthread.
85 *
86 * @const _PTHREAD_PRIORITY_ENFORCE_FLAG
87 * This flag is used to indicate that this priority should be prefered for work
88 * submited asynchronously over the intrinsic priority of the queue/thread the
89 * work is submitted to.
90 *
91 * @const _PTHREAD_PRIORITY_OVERRIDE_FLAG
92 * No longer used
93 */
94typedef unsigned long pthread_priority_t;
95
96#define _PTHREAD_PRIORITY_FLAGS_MASK 0xff000000
97#define _PTHREAD_PRIORITY_FLAGS_SHIFT (24ull)
98
99#define _PTHREAD_PRIORITY_OVERCOMMIT_FLAG 0x80000000
100#define _PTHREAD_PRIORITY_INHERIT_FLAG 0x40000000 /* dispatch only */
101#define _PTHREAD_PRIORITY_ROOTQUEUE_FLAG 0x20000000 /* dispatch only */
102#define _PTHREAD_PRIORITY_SCHED_PRI_FLAG 0x20000000
103#define _PTHREAD_PRIORITY_SCHED_PRI_MASK 0x0000ffff
104#define _PTHREAD_PRIORITY_ENFORCE_FLAG 0x10000000 /* dispatch only */
105#define _PTHREAD_PRIORITY_OVERRIDE_FLAG 0x08000000 /* unused */
106#define _PTHREAD_PRIORITY_FALLBACK_FLAG 0x04000000
107#define _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG 0x02000000
108#define _PTHREAD_PRIORITY_NEEDS_UNBIND_FLAG 0x01000000
109#define _PTHREAD_PRIORITY_DEFAULTQUEUE_FLAG _PTHREAD_PRIORITY_FALLBACK_FLAG // compat
110
111#define _PTHREAD_PRIORITY_ENCODING_MASK 0x00a00000
112#define _PTHREAD_PRIORITY_ENCODING_SHIFT (22ull)
113#define _PTHREAD_PRIORITY_ENCODING_V0 0x00000000
114#define _PTHREAD_PRIORITY_ENCODING_V1 0x00400000 /* unused */
115#define _PTHREAD_PRIORITY_ENCODING_V2 0x00800000 /* unused */
116#define _PTHREAD_PRIORITY_ENCODING_V3 0x00a00000 /* unused */
117
118#define _PTHREAD_PRIORITY_QOS_CLASS_MASK 0x003fff00
119#define _PTHREAD_PRIORITY_VALID_QOS_CLASS_MASK 0x00003f00
120#define _PTHREAD_PRIORITY_QOS_CLASS_SHIFT (8ull)
121
122#define _PTHREAD_PRIORITY_PRIORITY_MASK 0x000000ff
123#define _PTHREAD_PRIORITY_PRIORITY_SHIFT (0)
124
125#if PRIVATE
126#if XNU_KERNEL_PRIVATE && !defined(__PTHREAD_EXPOSE_INTERNALS__)
127#define __PTHREAD_EXPOSE_INTERNALS__ 1
128#endif // XNU_KERNEL_PRIVATE
129#ifdef __PTHREAD_EXPOSE_INTERNALS__
130/*
131 * This exposes the encoding used for pthread_priority_t
132 * and is meant to be used by pthread and XNU only
133 */
134#include <mach/thread_policy.h> // THREAD_QOS_*
135#include <stdbool.h>
136
137__attribute__((always_inline, const))
138static inline bool
139_pthread_priority_has_qos(pthread_priority_t pp)
140{
141 return (pp & (_PTHREAD_PRIORITY_SCHED_PRI_FLAG |
142 _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG)) == 0 &&
143 (pp & (_PTHREAD_PRIORITY_QOS_CLASS_MASK &
144 ~_PTHREAD_PRIORITY_VALID_QOS_CLASS_MASK)) == 0 &&
145 (pp & _PTHREAD_PRIORITY_VALID_QOS_CLASS_MASK) != 0;
146}
147
148__attribute__((always_inline, const))
149static inline pthread_priority_t
150_pthread_priority_make_from_thread_qos(thread_qos_t qos, int relpri,
151 unsigned long flags)
152{
153 pthread_priority_t pp = (flags & _PTHREAD_PRIORITY_FLAGS_MASK);
154 if (qos && qos < THREAD_QOS_LAST) {
155 pp |= (1 << (_PTHREAD_PRIORITY_QOS_CLASS_SHIFT + qos - 1));
156 pp |= ((uint8_t)relpri - 1) & _PTHREAD_PRIORITY_PRIORITY_MASK;
157 }
158 return pp;
159}
160
161__attribute__((always_inline, const))
162static inline pthread_priority_t
163_pthread_event_manager_priority(void)
164{
165 return _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG;
166}
167
168__attribute__((always_inline, const))
169static inline pthread_priority_t
170_pthread_unspecified_priority(void)
171{
172 return _pthread_priority_make_from_thread_qos(THREAD_QOS_UNSPECIFIED, 0, 0);
173}
174
175__attribute__((always_inline, const))
176static inline pthread_priority_t
177_pthread_default_priority(unsigned long flags)
178{
179 return _pthread_priority_make_from_thread_qos(THREAD_QOS_LEGACY, 0, flags);
180}
181
182__attribute__((always_inline, const))
183static inline thread_qos_t
184_pthread_priority_thread_qos(pthread_priority_t pp)
185{
186 if (_pthread_priority_has_qos(pp)) {
187 pp &= _PTHREAD_PRIORITY_QOS_CLASS_MASK;
188 pp >>= _PTHREAD_PRIORITY_QOS_CLASS_SHIFT;
189 return (thread_qos_t)__builtin_ffs((int)pp);
190 }
191 return THREAD_QOS_UNSPECIFIED;
192}
193
194__attribute__((always_inline, const))
195static inline int
196_pthread_priority_relpri(pthread_priority_t pp)
197{
198 if (_pthread_priority_has_qos(pp)) {
199 pp &= _PTHREAD_PRIORITY_PRIORITY_MASK;
200 pp >>= _PTHREAD_PRIORITY_PRIORITY_SHIFT;
201 return (int8_t)pp + 1;
202 }
203 return 0;
204}
205
206#if KERNEL
207// Interfaces only used by the kernel and not implemented in userspace.
208
209/*
210 * Keep managerness, overcomitness and fallback, discard other flags.
211 * Normalize and validate QoS/relpri
212 */
213__attribute__((const))
214pthread_priority_t
215_pthread_priority_normalize(pthread_priority_t pp);
216
217/*
218 * Keep managerness, discard other flags.
219 * Normalize and validate QoS/relpri
220 */
221__attribute__((const))
222pthread_priority_t
223_pthread_priority_normalize_for_ipc(pthread_priority_t pp);
224
225/*
226 * Keep the flags from base_pp and return the priority with the maximum priority
227 * of base_pp and _pthread_priority_make_from_thread_qos(qos, 0, 0)
228 */
229__attribute__((const))
230pthread_priority_t
231_pthread_priority_combine(pthread_priority_t base_pp, thread_qos_t qos);
232
233#endif // KERNEL
234#endif // __PTHREAD_EXPOSE_INTERNALS__
235#endif // PRIVATE
236#endif // _PTHREAD_PRIORITY_PRIVATE_H_
237