cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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irq.c (3112B)

      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(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 */
     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}