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/arch/um/os-Linux/irq.c

http://github.com/mirrors/linux
C | 147 lines | 89 code | 22 blank | 36 comment | 12 complexity | e2e84a02b119db25272231f12788d262 MD5 | raw file
  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
 19static int epollfd = -1;
 20
 21#define MAX_EPOLL_EVENTS 64
 22
 23static 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
 29void *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
 39int 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
 48int os_event_mask(int irq_type)
 49{
 50	if (irq_type == IRQ_READ)
 51		return EPOLLIN | EPOLLPRI;
 52	if (irq_type == IRQ_WRITE)
 53		return EPOLLOUT;
 54	return 0;
 55}
 56
 57/*
 58 * Initial Epoll Setup
 59 */
 60int 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 */
 69int 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 */
 92int 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 */
110int 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 */
127int os_del_epoll_fd(int fd)
128{
129	struct epoll_event event;
130	int result;
131	/* This is quiet as we use this as IO ON/OFF - so it is often
132	 * invoked on a non-existent fd
133	 */
134	result = epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, &event);
135	return result;
136}
137
138void os_set_ioignore(void)
139{
140	signal(SIGIO, SIG_IGN);
141}
142
143void os_close_epoll_fd(void)
144{
145	/* Needed so we do not leak an fd when rebooting */
146	os_close_file(epollfd);
147}