Commit | Line | Data |
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f1326973 EB |
1 | /* |
2 | * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...) | |
3 | * | |
4 | * Basic test to test behaviour of PR_GET_TSC and PR_SET_TSC | |
5 | */ | |
6 | ||
7 | #include <stdio.h> | |
8 | #include <stdlib.h> | |
9 | #include <unistd.h> | |
10 | #include <signal.h> | |
11 | #include <inttypes.h> | |
12 | ||
13 | ||
14 | #include <sys/prctl.h> | |
15 | #include <linux/prctl.h> | |
16 | ||
17 | /* Get/set the process' ability to use the timestamp counter instruction */ | |
18 | #ifndef PR_GET_TSC | |
19 | #define PR_GET_TSC 25 | |
20 | #define PR_SET_TSC 26 | |
21 | # define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */ | |
22 | # define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */ | |
23 | #endif | |
24 | ||
25 | const char *tsc_names[] = | |
26 | { | |
27 | [0] = "[not set]", | |
28 | [PR_TSC_ENABLE] = "PR_TSC_ENABLE", | |
29 | [PR_TSC_SIGSEGV] = "PR_TSC_SIGSEGV", | |
30 | }; | |
31 | ||
0421fc83 PF |
32 | static uint64_t rdtsc(void) |
33 | { | |
f1326973 EB |
34 | uint32_t lo, hi; |
35 | /* We cannot use "=A", since this would use %rax on x86_64 */ | |
36 | __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi)); | |
37 | return (uint64_t)hi << 32 | lo; | |
38 | } | |
39 | ||
0421fc83 | 40 | static void sigsegv_cb(int sig) |
f1326973 EB |
41 | { |
42 | int tsc_val = 0; | |
43 | ||
44 | printf("[ SIG_SEGV ]\n"); | |
45 | printf("prctl(PR_GET_TSC, &tsc_val); "); | |
46 | fflush(stdout); | |
47 | ||
48 | if ( prctl(PR_GET_TSC, &tsc_val) == -1) | |
49 | perror("prctl"); | |
50 | ||
51 | printf("tsc_val == %s\n", tsc_names[tsc_val]); | |
52 | printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n"); | |
53 | fflush(stdout); | |
54 | if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1) | |
55 | perror("prctl"); | |
56 | ||
57 | printf("rdtsc() == "); | |
58 | } | |
59 | ||
60 | int main(int argc, char **argv) | |
61 | { | |
62 | int tsc_val = 0; | |
63 | ||
64 | signal(SIGSEGV, sigsegv_cb); | |
65 | ||
66 | printf("rdtsc() == %llu\n", (unsigned long long)rdtsc()); | |
67 | printf("prctl(PR_GET_TSC, &tsc_val); "); | |
68 | fflush(stdout); | |
69 | ||
70 | if ( prctl(PR_GET_TSC, &tsc_val) == -1) | |
71 | perror("prctl"); | |
72 | ||
73 | printf("tsc_val == %s\n", tsc_names[tsc_val]); | |
74 | printf("rdtsc() == %llu\n", (unsigned long long)rdtsc()); | |
75 | printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n"); | |
76 | fflush(stdout); | |
77 | ||
78 | if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1) | |
79 | perror("prctl"); | |
80 | ||
81 | printf("rdtsc() == %llu\n", (unsigned long long)rdtsc()); | |
82 | printf("prctl(PR_SET_TSC, PR_TSC_SIGSEGV)\n"); | |
83 | fflush(stdout); | |
84 | ||
85 | if ( prctl(PR_SET_TSC, PR_TSC_SIGSEGV) == -1) | |
86 | perror("prctl"); | |
87 | ||
88 | printf("rdtsc() == "); | |
89 | fflush(stdout); | |
90 | printf("%llu\n", (unsigned long long)rdtsc()); | |
91 | fflush(stdout); | |
92 | ||
93 | exit(EXIT_SUCCESS); | |
94 | } | |
95 |