Erik Bosman | f132697 | 2008-04-11 18:57:22 +0200 | [diff] [blame] | 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 | |
Peter Foley | 0421fc8 | 2014-09-25 11:23:15 -0700 | [diff] [blame] | 32 | static uint64_t rdtsc(void) |
| 33 | { |
Erik Bosman | f132697 | 2008-04-11 18:57:22 +0200 | [diff] [blame] | 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 | |
Peter Foley | 0421fc8 | 2014-09-25 11:23:15 -0700 | [diff] [blame] | 40 | static void sigsegv_cb(int sig) |
Erik Bosman | f132697 | 2008-04-11 18:57:22 +0200 | [diff] [blame] | 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 | |
Mahesh Khanwalkar | f0cd147 | 2016-02-13 19:05:31 -0500 | [diff] [blame^] | 60 | int main(void) |
Erik Bosman | f132697 | 2008-04-11 18:57:22 +0200 | [diff] [blame] | 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 | |