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Commit 64ff5747 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Greg Kroah-Hartman
Browse files

selftests/x86: Add clock_gettime() tests to test_vdso 



commit 7c03e7035ac1cf2a6165754e4f3a49c2f1977838 upstream.

Now that the vDSO implementation of clock_gettime() is getting
reworked, add a selftest for it.  This tests that its output is
consistent with the syscall version.

This is marked for stable to serve as a test for commit

  715bd9d12f84 ("x86/vdso: Fix asm constraints on vDSO syscall fallbacks")

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/082399674de2619b2befd8c0dde49b260605b126.1538422295.git.luto@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 30500cc7

tools/testing/selftests/x86/test_vdso.c

+99 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <errno.h>

#include <sched.h>

#include <stdbool.h>

#include <limits.h>



#ifndef SYS_getcpu

# ifdef __x86_64__
@@ -31,6 +32,10 @@ 


int nerrs = 0;



typedef int (*vgettime_t)(clockid_t, struct timespec *);



vgettime_t vdso_clock_gettime;



typedef long (*getcpu_t)(unsigned *, unsigned *, void *);



getcpu_t vgetcpu;
@@ -95,6 +100,10 @@ static void fill_function_pointers() 
		printf("Warning: failed to find getcpu in vDSO\n");



	vgetcpu = (getcpu_t) vsyscall_getcpu();



	vdso_clock_gettime = (vgettime_t)dlsym(vdso, "__vdso_clock_gettime");

	if (!vdso_clock_gettime)

		printf("Warning: failed to find clock_gettime in vDSO\n");

}



static long sys_getcpu(unsigned * cpu, unsigned * node,
@@ -103,6 +112,11 @@ static long sys_getcpu(unsigned * cpu, unsigned * node, 
	return syscall(__NR_getcpu, cpu, node, cache);

}



static inline int sys_clock_gettime(clockid_t id, struct timespec *ts)

{

	return syscall(__NR_clock_gettime, id, ts);

}



static void test_getcpu(void)

{

	printf("[RUN]\tTesting getcpu...\n");
@@ -155,10 +169,95 @@ static void test_getcpu(void) 
	}

}



static bool ts_leq(const struct timespec *a, const struct timespec *b)

{

	if (a->tv_sec != b->tv_sec)

		return a->tv_sec < b->tv_sec;

	else

		return a->tv_nsec <= b->tv_nsec;

}



static char const * const clocknames[] = {

	[0] = "CLOCK_REALTIME",

	[1] = "CLOCK_MONOTONIC",

	[2] = "CLOCK_PROCESS_CPUTIME_ID",

	[3] = "CLOCK_THREAD_CPUTIME_ID",

	[4] = "CLOCK_MONOTONIC_RAW",

	[5] = "CLOCK_REALTIME_COARSE",

	[6] = "CLOCK_MONOTONIC_COARSE",

	[7] = "CLOCK_BOOTTIME",

	[8] = "CLOCK_REALTIME_ALARM",

	[9] = "CLOCK_BOOTTIME_ALARM",

	[10] = "CLOCK_SGI_CYCLE",

	[11] = "CLOCK_TAI",

};



static void test_one_clock_gettime(int clock, const char *name)

{

	struct timespec start, vdso, end;

	int vdso_ret, end_ret;



	printf("[RUN]\tTesting clock_gettime for clock %s (%d)...\n", name, clock);



	if (sys_clock_gettime(clock, &start) < 0) {

		if (errno == EINVAL) {

			vdso_ret = vdso_clock_gettime(clock, &vdso);

			if (vdso_ret == -EINVAL) {

				printf("[OK]\tNo such clock.\n");

			} else {

				printf("[FAIL]\tNo such clock, but __vdso_clock_gettime returned %d\n", vdso_ret);

				nerrs++;

			}

		} else {

			printf("[WARN]\t clock_gettime(%d) syscall returned error %d\n", clock, errno);

		}

		return;

	}



	vdso_ret = vdso_clock_gettime(clock, &vdso);

	end_ret = sys_clock_gettime(clock, &end);



	if (vdso_ret != 0 || end_ret != 0) {

		printf("[FAIL]\tvDSO returned %d, syscall errno=%d\n",

		       vdso_ret, errno);

		nerrs++;

		return;

	}



	printf("\t%llu.%09ld %llu.%09ld %llu.%09ld\n",

	       (unsigned long long)start.tv_sec, start.tv_nsec,

	       (unsigned long long)vdso.tv_sec, vdso.tv_nsec,

	       (unsigned long long)end.tv_sec, end.tv_nsec);



	if (!ts_leq(&start, &vdso) || !ts_leq(&vdso, &end)) {

		printf("[FAIL]\tTimes are out of sequence\n");

		nerrs++;

	}

}



static void test_clock_gettime(void)

{

	for (int clock = 0; clock < sizeof(clocknames) / sizeof(clocknames[0]);

	     clock++) {

		test_one_clock_gettime(clock, clocknames[clock]);

	}



	/* Also test some invalid clock ids */

	test_one_clock_gettime(-1, "invalid");

	test_one_clock_gettime(INT_MIN, "invalid");

	test_one_clock_gettime(INT_MAX, "invalid");

}



int main(int argc, char **argv)

{

	fill_function_pointers();



	test_clock_gettime();



	/*

	 * Test getcpu() last so that, if something goes wrong setting affinity,

	 * we still run the other tests.

	 */

	test_getcpu();



	return nerrs ? 1 : 0;