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