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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rtc_user.c (1534B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (C) 2020 Intel Corporation
      4 * Author: Johannes Berg <johannes@sipsolutions.net>
      5 */
      6#include <stdbool.h>
      7#include <os.h>
      8#include <errno.h>
      9#include <sched.h>
     10#include <unistd.h>
     11#include <kern_util.h>
     12#include <sys/select.h>
     13#include <stdio.h>
     14#include <sys/timerfd.h>
     15#include "rtc.h"
     16
     17static int uml_rtc_irq_fds[2];
     18
     19void uml_rtc_send_timetravel_alarm(void)
     20{
     21	unsigned long long c = 1;
     22
     23	CATCH_EINTR(write(uml_rtc_irq_fds[1], &c, sizeof(c)));
     24}
     25
     26int uml_rtc_start(bool timetravel)
     27{
     28	int err;
     29
     30	if (timetravel) {
     31		int err = os_pipe(uml_rtc_irq_fds, 1, 1);
     32		if (err)
     33			goto fail;
     34	} else {
     35		uml_rtc_irq_fds[0] = timerfd_create(CLOCK_REALTIME, TFD_CLOEXEC);
     36		if (uml_rtc_irq_fds[0] < 0) {
     37			err = -errno;
     38			goto fail;
     39		}
     40
     41		/* apparently timerfd won't send SIGIO, use workaround */
     42		sigio_broken(uml_rtc_irq_fds[0]);
     43		err = add_sigio_fd(uml_rtc_irq_fds[0]);
     44		if (err < 0) {
     45			close(uml_rtc_irq_fds[0]);
     46			goto fail;
     47		}
     48	}
     49
     50	return uml_rtc_irq_fds[0];
     51fail:
     52	uml_rtc_stop(timetravel);
     53	return err;
     54}
     55
     56int uml_rtc_enable_alarm(unsigned long long delta_seconds)
     57{
     58	struct itimerspec it = {
     59		.it_value = {
     60			.tv_sec = delta_seconds,
     61		},
     62	};
     63
     64	if (timerfd_settime(uml_rtc_irq_fds[0], 0, &it, NULL))
     65		return -errno;
     66	return 0;
     67}
     68
     69void uml_rtc_disable_alarm(void)
     70{
     71	uml_rtc_enable_alarm(0);
     72}
     73
     74void uml_rtc_stop(bool timetravel)
     75{
     76	if (timetravel)
     77		os_close_file(uml_rtc_irq_fds[1]);
     78	else
     79		ignore_sigio_fd(uml_rtc_irq_fds[0]);
     80	os_close_file(uml_rtc_irq_fds[0]);
     81}