1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2017 - Cambridge Greys Ltd
4 * Copyright (C) 2011 - 2014 Cisco Systems Inc
5 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
6 */
7
8 #include <stdlib.h>
9 #include <errno.h>
10 #include <sys/epoll.h>
11 #include <signal.h>
12 #include <string.h>
13 #include <irq_user.h>
14 #include <os.h>
15 #include <um_malloc.h>
16
17 /* Epoll support */
18
19 static int epollfd = -1;
20
21 #define MAX_EPOLL_EVENTS 64
22
23 static struct epoll_event epoll_events[MAX_EPOLL_EVENTS];
24
25 /* Helper to return an Epoll data pointer from an epoll event structure.
26 * We need to keep this one on the userspace side to keep includes separate
27 */
28
29 void *os_epoll_get_data_pointer(int index)
30 {
31 return epoll_events[index].data.ptr;
32 }
33
34 /* Helper to compare events versus the events in the epoll structure.
35 * Same as above - needs to be on the userspace side
36 */
37
38
39 int os_epoll_triggered(int index, int events)
40 {
41 return epoll_events[index].events & events;
42 }
43 /* Helper to set the event mask.
44 * The event mask is opaque to the kernel side, because it does not have
45 * access to the right includes/defines for EPOLL constants.
46 */
47
48 int os_event_mask(enum um_irq_type irq_type)
49 {
50 if (irq_type == IRQ_READ)
51 return EPOLLIN | EPOLLPRI | EPOLLERR | EPOLLHUP | EPOLLRDHUP;
52 if (irq_type == IRQ_WRITE)
53 return EPOLLOUT;
54 return 0;
55 }
56
57 /*
58 * Initial Epoll Setup
59 */
60 int os_setup_epoll(void)
61 {
62 epollfd = epoll_create(MAX_EPOLL_EVENTS);
63 return epollfd;
64 }
65
66 /*
67 * Helper to run the actual epoll_wait
68 */
69 int os_waiting_for_events_epoll(void)
70 {
71 int n, err;
72
73 n = epoll_wait(epollfd,
74 (struct epoll_event *) &epoll_events, MAX_EPOLL_EVENTS, 0);
75 if (n < 0) {
76 err = -errno;
77 if (errno != EINTR)
78 printk(
79 UM_KERN_ERR "os_waiting_for_events:"
80 " epoll returned %d, error = %s\n", n,
81 strerror(errno)
82 );
83 return err;
84 }
85 return n;
86 }
87
88
89 /*
90 * Helper to add a fd to epoll
91 */
92 int os_add_epoll_fd(int events, int fd, void *data)
93 {
94 struct epoll_event event;
95 int result;
96
97 event.data.ptr = data;
98 event.events = events | EPOLLET;
99 result = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &event);
100 if ((result) && (errno == EEXIST))
101 result = os_mod_epoll_fd(events, fd, data);
102 if (result)
103 printk("epollctl add err fd %d, %s\n", fd, strerror(errno));
104 return result;
105 }
106
107 /*
108 * Helper to mod the fd event mask and/or data backreference
109 */
110 int os_mod_epoll_fd(int events, int fd, void *data)
111 {
112 struct epoll_event event;
113 int result;
114
115 event.data.ptr = data;
116 event.events = events;
117 result = epoll_ctl(epollfd, EPOLL_CTL_MOD, fd, &event);
118 if (result)
119 printk(UM_KERN_ERR
120 "epollctl mod err fd %d, %s\n", fd, strerror(errno));
121 return result;
122 }
123
124 /*
125 * Helper to delete the epoll fd
126 */
127 int os_del_epoll_fd(int fd)
128 {
129 struct epoll_event event;
130 /* This is quiet as we use this as IO ON/OFF - so it is often
131 * invoked on a non-existent fd
132 */
133 return epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, &event);
134 }
135
136 void os_set_ioignore(void)
137 {
138 signal(SIGIO, SIG_IGN);
139 }
140
141 void os_close_epoll_fd(void)
142 {
143 /* Needed so we do not leak an fd when rebooting */
144 os_close_file(epollfd);
145 }
146
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