96 lines
2.1 KiB
C
96 lines
2.1 KiB
C
/*
|
|
* 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",
|
|
};
|
|
|
|
static uint64_t rdtsc(void)
|
|
{
|
|
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;
|
|
}
|
|
|
|
static void sigsegv_cb(int sig)
|
|
{
|
|
int tsc_val = 0;
|
|
|
|
printf("[ SIG_SEGV ]\n");
|
|
printf("prctl(PR_GET_TSC, &tsc_val); ");
|
|
fflush(stdout);
|
|
|
|
if ( prctl(PR_GET_TSC, &tsc_val) == -1)
|
|
perror("prctl");
|
|
|
|
printf("tsc_val == %s\n", tsc_names[tsc_val]);
|
|
printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n");
|
|
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\n", (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\n", tsc_names[tsc_val]);
|
|
printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
|
|
printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n");
|
|
fflush(stdout);
|
|
|
|
if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1)
|
|
perror("prctl");
|
|
|
|
printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
|
|
printf("prctl(PR_SET_TSC, PR_TSC_SIGSEGV)\n");
|
|
fflush(stdout);
|
|
|
|
if ( prctl(PR_SET_TSC, PR_TSC_SIGSEGV) == -1)
|
|
perror("prctl");
|
|
|
|
printf("rdtsc() == ");
|
|
fflush(stdout);
|
|
printf("%llu\n", (unsigned long long)rdtsc());
|
|
fflush(stdout);
|
|
|
|
exit(EXIT_SUCCESS);
|
|
}
|
|
|