srso.c

 1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/perf_event.h>
 3#include <cpuid.h>
 4#include <errno.h>
 5#include <stdio.h>
 6#include <stdlib.h>
 7#include <string.h>
 8#include <sys/ioctl.h>
 9#include <sys/syscall.h>
10#include <unistd.h>
11
12int main(void)
13{
14	struct perf_event_attr ret_attr, mret_attr;
15	long long count_rets, count_rets_mispred;
16	int rrets_fd, mrrets_fd;
17	unsigned int cpuid1_eax, b, c, d;
18
19	__cpuid(1, cpuid1_eax, b, c, d);
20
21	if (cpuid1_eax < 0x00800f00 ||
22	    cpuid1_eax > 0x00afffff) {
23		fprintf(stderr, "This needs to run on a Zen[1-4] machine (CPUID(1).EAX: 0x%x). Exiting...\n", cpuid1_eax);
24		exit(EXIT_FAILURE);
25	}
26
27	memset(&ret_attr, 0, sizeof(struct perf_event_attr));
28	memset(&mret_attr, 0, sizeof(struct perf_event_attr));
29
30	ret_attr.type = mret_attr.type = PERF_TYPE_RAW;
31	ret_attr.size = mret_attr.size = sizeof(struct perf_event_attr);
32	ret_attr.config = 0xc8;
33	mret_attr.config = 0xc9;
34	ret_attr.disabled = mret_attr.disabled = 1;
35	ret_attr.exclude_user = mret_attr.exclude_user = 1;
36	ret_attr.exclude_hv = mret_attr.exclude_hv = 1;
37
38	rrets_fd = syscall(SYS_perf_event_open, &ret_attr, 0, -1, -1, 0);
39	if (rrets_fd == -1) {
40		perror("opening retired RETs fd");
41		exit(EXIT_FAILURE);
42	}
43
44	mrrets_fd = syscall(SYS_perf_event_open, &mret_attr, 0, -1, -1, 0);
45	if (mrrets_fd == -1) {
46		perror("opening retired mispredicted RETs fd");
47		exit(EXIT_FAILURE);
48	}
49
50	ioctl(rrets_fd, PERF_EVENT_IOC_RESET, 0);
51	ioctl(mrrets_fd, PERF_EVENT_IOC_RESET, 0);
52
53	ioctl(rrets_fd, PERF_EVENT_IOC_ENABLE, 0);
54	ioctl(mrrets_fd, PERF_EVENT_IOC_ENABLE, 0);
55
56	printf("Sleeping for 10 seconds\n");
57	sleep(10);
58
59	ioctl(rrets_fd, PERF_EVENT_IOC_DISABLE, 0);
60	ioctl(mrrets_fd, PERF_EVENT_IOC_DISABLE, 0);
61
62	read(rrets_fd, &count_rets, sizeof(long long));
63	read(mrrets_fd, &count_rets_mispred, sizeof(long long));
64
65	printf("RETs: (%lld retired <-> %lld mispredicted)\n",
66		count_rets, count_rets_mispred);
67	printf("SRSO Safe-RET mitigation works correctly if both counts are almost equal.\n");
68
69	return 0;
70}