Blame view
Documentation/prctl/disable-tsc-test.c
2.07 KB
f13269732 generic, x86: add... |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 |
/* * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...) * * Basic test to test behaviour of PR_GET_TSC and PR_SET_TSC */ #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <signal.h> #include <inttypes.h> #include <sys/prctl.h> #include <linux/prctl.h> /* Get/set the process' ability to use the timestamp counter instruction */ #ifndef PR_GET_TSC #define PR_GET_TSC 25 #define PR_SET_TSC 26 # define PR_TSC_ENABLE 1 /* allow the use of the timestamp counter */ # define PR_TSC_SIGSEGV 2 /* throw a SIGSEGV instead of reading the TSC */ #endif const char *tsc_names[] = { [0] = "[not set]", [PR_TSC_ENABLE] = "PR_TSC_ENABLE", [PR_TSC_SIGSEGV] = "PR_TSC_SIGSEGV", }; uint64_t rdtsc() { uint32_t lo, hi; /* We cannot use "=A", since this would use %rax on x86_64 */ __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi)); return (uint64_t)hi << 32 | lo; } void sigsegv_cb(int sig) { int tsc_val = 0; printf("[ SIG_SEGV ] "); printf("prctl(PR_GET_TSC, &tsc_val); "); fflush(stdout); if ( prctl(PR_GET_TSC, &tsc_val) == -1) perror("prctl"); printf("tsc_val == %s ", tsc_names[tsc_val]); printf("prctl(PR_SET_TSC, PR_TSC_ENABLE) "); fflush(stdout); if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1) perror("prctl"); printf("rdtsc() == "); } int main(int argc, char **argv) { int tsc_val = 0; signal(SIGSEGV, sigsegv_cb); printf("rdtsc() == %llu ", (unsigned long long)rdtsc()); printf("prctl(PR_GET_TSC, &tsc_val); "); fflush(stdout); if ( prctl(PR_GET_TSC, &tsc_val) == -1) perror("prctl"); printf("tsc_val == %s ", tsc_names[tsc_val]); printf("rdtsc() == %llu ", (unsigned long long)rdtsc()); printf("prctl(PR_SET_TSC, PR_TSC_ENABLE) "); fflush(stdout); if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1) perror("prctl"); printf("rdtsc() == %llu ", (unsigned long long)rdtsc()); printf("prctl(PR_SET_TSC, PR_TSC_SIGSEGV) "); fflush(stdout); if ( prctl(PR_SET_TSC, PR_TSC_SIGSEGV) == -1) perror("prctl"); printf("rdtsc() == "); fflush(stdout); printf("%llu ", (unsigned long long)rdtsc()); fflush(stdout); exit(EXIT_SUCCESS); } |