[net-next-2.6.git] / Documentation / prctl / disable-tsc-test.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",
};

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 ]\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);
}
Commit	Line	Data
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
	32	uint64_t rdtsc() {
	33	uint32_t lo, hi;
	34	/* We cannot use "=A", since this would use %rax on x86_64 */
	35	__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
	36	return (uint64_t)hi << 32 \| lo;
	37	}
	38
	39	void sigsegv_cb(int sig)
	40	{
	41	int tsc_val = 0;
	42
	43	printf("[ SIG_SEGV ]\n");
	44	printf("prctl(PR_GET_TSC, &tsc_val); ");
	45	fflush(stdout);
	46
	47	if ( prctl(PR_GET_TSC, &tsc_val) == -1)
	48	perror("prctl");
	49
	50	printf("tsc_val == %s\n", tsc_names[tsc_val]);
	51	printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n");
	52	fflush(stdout);
	53	if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1)
	54	perror("prctl");
	55
	56	printf("rdtsc() == ");
	57	}
	58
	59	int main(int argc, char **argv)
	60	{
	61	int tsc_val = 0;
	62
	63	signal(SIGSEGV, sigsegv_cb);
	64
65	printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
66	printf("prctl(PR_GET_TSC, &tsc_val); ");
67	fflush(stdout);
68
69	if ( prctl(PR_GET_TSC, &tsc_val) == -1)
70	perror("prctl");
71
72	printf("tsc_val == %s\n", tsc_names[tsc_val]);
73	printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
74	printf("prctl(PR_SET_TSC, PR_TSC_ENABLE)\n");
75	fflush(stdout);
76
77	if ( prctl(PR_SET_TSC, PR_TSC_ENABLE) == -1)
78	perror("prctl");
79
80	printf("rdtsc() == %llu\n", (unsigned long long)rdtsc());
81	printf("prctl(PR_SET_TSC, PR_TSC_SIGSEGV)\n");
82	fflush(stdout);
83
84	if ( prctl(PR_SET_TSC, PR_TSC_SIGSEGV) == -1)
85	perror("prctl");
86
87	printf("rdtsc() == ");
88	fflush(stdout);
89	printf("%llu\n", (unsigned long long)rdtsc());
90	fflush(stdout);
91
92	exit(EXIT_SUCCESS);
93	}
94