tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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}