cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

rtcpie.c (3210B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Real Time Clock Periodic Interrupt test program
      4 *
      5 * Since commit 6610e0893b8bc ("RTC: Rework RTC code to use timerqueue for
      6 * events"), PIE are completely handled using hrtimers, without actually using
      7 * any underlying hardware RTC.
      8 *
      9 */
     10
     11#include <stdio.h>
     12#include <linux/rtc.h>
     13#include <sys/ioctl.h>
     14#include <sys/time.h>
     15#include <sys/types.h>
     16#include <fcntl.h>
     17#include <unistd.h>
     18#include <stdlib.h>
     19#include <errno.h>
     20
     21#include "../kselftest.h"
     22
     23/*
     24 * This expects the new RTC class driver framework, working with
     25 * clocks that will often not be clones of what the PC-AT had.
     26 * Use the command line to specify another RTC if you need one.
     27 */
     28static const char default_rtc[] = "/dev/rtc0";
     29
     30int main(int argc, char **argv)
     31{
     32	int i, fd, retval, irqcount = 0;
     33	unsigned long tmp, data, old_pie_rate;
     34	const char *rtc = default_rtc;
     35	struct timeval start, end, diff;
     36
     37	switch (argc) {
     38	case 2:
     39		rtc = argv[1];
     40		break;
     41	case 1:
     42		fd = open(default_rtc, O_RDONLY);
     43		if (fd == -1) {
     44			printf("Default RTC %s does not exist. Test Skipped!\n", default_rtc);
     45			exit(KSFT_SKIP);
     46		}
     47		close(fd);
     48		break;
     49	default:
     50		fprintf(stderr, "usage:  rtctest [rtcdev] [d]\n");
     51		return 1;
     52	}
     53
     54	fd = open(rtc, O_RDONLY);
     55
     56	if (fd ==  -1) {
     57		perror(rtc);
     58		exit(errno);
     59	}
     60
     61	/* Read periodic IRQ rate */
     62	retval = ioctl(fd, RTC_IRQP_READ, &old_pie_rate);
     63	if (retval == -1) {
     64		/* not all RTCs support periodic IRQs */
     65		if (errno == EINVAL) {
     66			fprintf(stderr, "\nNo periodic IRQ support\n");
     67			goto done;
     68		}
     69		perror("RTC_IRQP_READ ioctl");
     70		exit(errno);
     71	}
     72	fprintf(stderr, "\nPeriodic IRQ rate is %ldHz.\n", old_pie_rate);
     73
     74	fprintf(stderr, "Counting 20 interrupts at:");
     75	fflush(stderr);
     76
     77	/* The frequencies 128Hz, 256Hz, ... 8192Hz are only allowed for root. */
     78	for (tmp=2; tmp<=64; tmp*=2) {
     79
     80		retval = ioctl(fd, RTC_IRQP_SET, tmp);
     81		if (retval == -1) {
     82			/* not all RTCs can change their periodic IRQ rate */
     83			if (errno == EINVAL) {
     84				fprintf(stderr,
     85					"\n...Periodic IRQ rate is fixed\n");
     86				goto done;
     87			}
     88			perror("RTC_IRQP_SET ioctl");
     89			exit(errno);
     90		}
     91
     92		fprintf(stderr, "\n%ldHz:\t", tmp);
     93		fflush(stderr);
     94
     95		/* Enable periodic interrupts */
     96		retval = ioctl(fd, RTC_PIE_ON, 0);
     97		if (retval == -1) {
     98			perror("RTC_PIE_ON ioctl");
     99			exit(errno);
    100		}
    101
    102		for (i=1; i<21; i++) {
    103			gettimeofday(&start, NULL);
    104			/* This blocks */
    105			retval = read(fd, &data, sizeof(unsigned long));
    106			if (retval == -1) {
    107				perror("read");
    108				exit(errno);
    109			}
    110			gettimeofday(&end, NULL);
    111			timersub(&end, &start, &diff);
    112			if (diff.tv_sec > 0 ||
    113			    diff.tv_usec > ((1000000L / tmp) * 1.10)) {
    114				fprintf(stderr, "\nPIE delta error: %ld.%06ld should be close to 0.%06ld\n",
    115				       diff.tv_sec, diff.tv_usec,
    116				       (1000000L / tmp));
    117				fflush(stdout);
    118				exit(-1);
    119			}
    120
    121			fprintf(stderr, " %d",i);
    122			fflush(stderr);
    123			irqcount++;
    124		}
    125
    126		/* Disable periodic interrupts */
    127		retval = ioctl(fd, RTC_PIE_OFF, 0);
    128		if (retval == -1) {
    129			perror("RTC_PIE_OFF ioctl");
    130			exit(errno);
    131		}
    132	}
    133
    134done:
    135	ioctl(fd, RTC_IRQP_SET, old_pie_rate);
    136
    137	fprintf(stderr, "\n\n\t\t\t *** Test complete ***\n");
    138
    139	close(fd);
    140
    141	return 0;
    142}