xref: /linux/include/uapi/linux/eventpoll.h (revision 100c85421b52e41269ada88f7d71a6b8a06c7a11)
1 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
2 /*
3  *  include/linux/eventpoll.h ( Efficient event polling implementation )
4  *  Copyright (C) 2001,...,2006	 Davide Libenzi
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  Davide Libenzi <davidel@xmailserver.org>
12  *
13  */
14 
15 #ifndef _UAPI_LINUX_EVENTPOLL_H
16 #define _UAPI_LINUX_EVENTPOLL_H
17 
18 /* For O_CLOEXEC */
19 #include <linux/fcntl.h>
20 #include <linux/types.h>
21 
22 /* Flags for epoll_create1.  */
23 #define EPOLL_CLOEXEC O_CLOEXEC
24 
25 /* Valid opcodes to issue to sys_epoll_ctl() */
26 #define EPOLL_CTL_ADD 1
27 #define EPOLL_CTL_DEL 2
28 #define EPOLL_CTL_MOD 3
29 
30 /* Epoll event masks */
31 #define EPOLLIN		(__force __poll_t)0x00000001
32 #define EPOLLPRI	(__force __poll_t)0x00000002
33 #define EPOLLOUT	(__force __poll_t)0x00000004
34 #define EPOLLERR	(__force __poll_t)0x00000008
35 #define EPOLLHUP	(__force __poll_t)0x00000010
36 #define EPOLLNVAL	(__force __poll_t)0x00000020
37 #define EPOLLRDNORM	(__force __poll_t)0x00000040
38 #define EPOLLRDBAND	(__force __poll_t)0x00000080
39 #define EPOLLWRNORM	(__force __poll_t)0x00000100
40 #define EPOLLWRBAND	(__force __poll_t)0x00000200
41 #define EPOLLMSG	(__force __poll_t)0x00000400
42 #define EPOLLRDHUP	(__force __poll_t)0x00002000
43 
44 /*
45  * Internal flag - wakeup generated by io_uring, used to detect recursion back
46  * into the io_uring poll handler.
47  */
48 #define EPOLL_URING_WAKE	((__force __poll_t)(1U << 27))
49 
50 /* Set exclusive wakeup mode for the target file descriptor */
51 #define EPOLLEXCLUSIVE	((__force __poll_t)(1U << 28))
52 
53 /*
54  * Request the handling of system wakeup events so as to prevent system suspends
55  * from happening while those events are being processed.
56  *
57  * Assuming neither EPOLLET nor EPOLLONESHOT is set, system suspends will not be
58  * re-allowed until epoll_wait is called again after consuming the wakeup
59  * event(s).
60  *
61  * Requires CAP_BLOCK_SUSPEND
62  */
63 #define EPOLLWAKEUP	((__force __poll_t)(1U << 29))
64 
65 /* Set the One Shot behaviour for the target file descriptor */
66 #define EPOLLONESHOT	((__force __poll_t)(1U << 30))
67 
68 /* Set the Edge Triggered behaviour for the target file descriptor */
69 #define EPOLLET		((__force __poll_t)(1U << 31))
70 
71 /*
72  * On x86-64 make the 64bit structure have the same alignment as the
73  * 32bit structure. This makes 32bit emulation easier.
74  *
75  * UML/x86_64 needs the same packing as x86_64
76  */
77 #ifdef __x86_64__
78 #define EPOLL_PACKED __attribute__((packed))
79 #else
80 #define EPOLL_PACKED
81 #endif
82 
83 struct epoll_event {
84 	__poll_t events;
85 	__u64 data;
86 } EPOLL_PACKED;
87 
88 struct epoll_params {
89 	__u32 busy_poll_usecs;
90 	__u16 busy_poll_budget;
91 	__u8 prefer_busy_poll;
92 
93 	/* pad the struct to a multiple of 64bits */
94 	__u8 __pad;
95 };
96 
97 #define EPOLL_IOC_TYPE 0x8A
98 #define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params)
99 #define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params)
100 
101 #endif /* _UAPI_LINUX_EVENTPOLL_H */
102