1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...)
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Basic test to test behaviour of PR_GET_TSC and PR_SET_TSC
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun #include <stdio.h>
9*4882a593Smuzhiyun #include <stdlib.h>
10*4882a593Smuzhiyun #include <unistd.h>
11*4882a593Smuzhiyun #include <signal.h>
12*4882a593Smuzhiyun #include <inttypes.h>
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun #include <sys/prctl.h>
16*4882a593Smuzhiyun #include <linux/prctl.h>
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun /* Get/set the process' ability to use the timestamp counter instruction */
19*4882a593Smuzhiyun #ifndef PR_GET_TSC
20*4882a593Smuzhiyun #define PR_GET_TSC 25
21*4882a593Smuzhiyun #define PR_SET_TSC 26
22*4882a593Smuzhiyun # define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */
23*4882a593Smuzhiyun # define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */
24*4882a593Smuzhiyun #endif
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun const char *tsc_names[] =
27*4882a593Smuzhiyun {
28*4882a593Smuzhiyun [0] = "[not set]",
29*4882a593Smuzhiyun [PR_TSC_ENABLE] = "PR_TSC_ENABLE",
30*4882a593Smuzhiyun [PR_TSC_SIGSEGV] = "PR_TSC_SIGSEGV",
31*4882a593Smuzhiyun };
32*4882a593Smuzhiyun
rdtsc(void)33*4882a593Smuzhiyun static uint64_t rdtsc(void)
34*4882a593Smuzhiyun {
35*4882a593Smuzhiyun uint32_t lo, hi;
36*4882a593Smuzhiyun /* We cannot use "=A", since this would use %rax on x86_64 */
37*4882a593Smuzhiyun __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
38*4882a593Smuzhiyun return (uint64_t)hi << 32 | lo;
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun
sigsegv_cb(int sig)41*4882a593Smuzhiyun static void sigsegv_cb(int sig)
42*4882a593Smuzhiyun {
43*4882a593Smuzhiyun int tsc_val = 0;
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun printf("[ SIG_SEGV ]\n");
46*4882a593Smuzhiyun printf("prctl(PR_GET_TSC, &tsc_val); ");
47*4882a593Smuzhiyun fflush(stdout);
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun if ( prctl(PR_GET_TSC, &tsc_val) == -1)
50*4882a593Smuzhiyun perror("prctl");
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun printf("tsc_val == %s\n", tsc_names[tsc_val]);
53*4882a593Smuzhiyun printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n");
54*4882a593Smuzhiyun fflush(stdout);
55*4882a593Smuzhiyun if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1)
56*4882a593Smuzhiyun perror("prctl");
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun printf("rdtsc() == ");
59*4882a593Smuzhiyun }
60*4882a593Smuzhiyun
main(void)61*4882a593Smuzhiyun int main(void)
62*4882a593Smuzhiyun {
63*4882a593Smuzhiyun int tsc_val = 0;
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun signal(SIGSEGV, sigsegv_cb);
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
68*4882a593Smuzhiyun printf("prctl(PR_GET_TSC, &tsc_val); ");
69*4882a593Smuzhiyun fflush(stdout);
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun if ( prctl(PR_GET_TSC, &tsc_val) == -1)
72*4882a593Smuzhiyun perror("prctl");
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun printf("tsc_val == %s\n", tsc_names[tsc_val]);
75*4882a593Smuzhiyun printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
76*4882a593Smuzhiyun printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n");
77*4882a593Smuzhiyun fflush(stdout);
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1)
80*4882a593Smuzhiyun perror("prctl");
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
83*4882a593Smuzhiyun printf("prctl(PR_SET_TSC, PR_TSC_SIGSEGV)\n");
84*4882a593Smuzhiyun fflush(stdout);
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun if ( prctl(PR_SET_TSC, PR_TSC_SIGSEGV) == -1)
87*4882a593Smuzhiyun perror("prctl");
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun printf("rdtsc() == ");
90*4882a593Smuzhiyun fflush(stdout);
91*4882a593Smuzhiyun printf("%llu\n", (unsigned long long)rdtsc());
92*4882a593Smuzhiyun fflush(stdout);
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun exit(EXIT_SUCCESS);
95*4882a593Smuzhiyun }
96*4882a593Smuzhiyun
97