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

example.c (1778B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright (c) 2021, Microsoft Corporation.
      4 *
      5 * Authors:
      6 *   Beau Belgrave <beaub@linux.microsoft.com>
      7 */
      8
      9#include <errno.h>
     10#include <sys/ioctl.h>
     11#include <sys/mman.h>
     12#include <fcntl.h>
     13#include <stdio.h>
     14#include <unistd.h>
     15#include <linux/user_events.h>
     16
     17/* Assumes debugfs is mounted */
     18const char *data_file = "/sys/kernel/debug/tracing/user_events_data";
     19const char *status_file = "/sys/kernel/debug/tracing/user_events_status";
     20
     21static int event_status(char **status)
     22{
     23	int fd = open(status_file, O_RDONLY);
     24
     25	*status = mmap(NULL, sysconf(_SC_PAGESIZE), PROT_READ,
     26		       MAP_SHARED, fd, 0);
     27
     28	close(fd);
     29
     30	if (*status == MAP_FAILED)
     31		return -1;
     32
     33	return 0;
     34}
     35
     36static int event_reg(int fd, const char *command, int *status, int *write)
     37{
     38	struct user_reg reg = {0};
     39
     40	reg.size = sizeof(reg);
     41	reg.name_args = (__u64)command;
     42
     43	if (ioctl(fd, DIAG_IOCSREG, &reg) == -1)
     44		return -1;
     45
     46	*status = reg.status_index;
     47	*write = reg.write_index;
     48
     49	return 0;
     50}
     51
     52int main(int argc, char **argv)
     53{
     54	int data_fd, status, write;
     55	char *status_page;
     56	struct iovec io[2];
     57	__u32 count = 0;
     58
     59	if (event_status(&status_page) == -1)
     60		return errno;
     61
     62	data_fd = open(data_file, O_RDWR);
     63
     64	if (event_reg(data_fd, "test u32 count", &status, &write) == -1)
     65		return errno;
     66
     67	/* Setup iovec */
     68	io[0].iov_base = &write;
     69	io[0].iov_len = sizeof(write);
     70	io[1].iov_base = &count;
     71	io[1].iov_len = sizeof(count);
     72
     73ask:
     74	printf("Press enter to check status...\n");
     75	getchar();
     76
     77	/* Check if anyone is listening */
     78	if (status_page[status]) {
     79		/* Yep, trace out our data */
     80		writev(data_fd, (const struct iovec *)io, 2);
     81
     82		/* Increase the count */
     83		count++;
     84
     85		printf("Something was attached, wrote data\n");
     86	}
     87
     88	goto ask;
     89
     90	return 0;
     91}